1107_BuncombeCo_CDLF_PH6GeotechReport_DIN28511_20170921

BUNNELL-LAMMONS ENGINEERING, INC.
GEOTECHNICAL, ENVIRONMENTAL AND CONSTRUCTION MATERIALS CONSULTANTS

6004 PONDERS COURT PHONE [phone]
GREENVILLE, SOUTH CAROLINA 29615 FAX [phone]

September 21, 2017

Environmental Infrastructure Consulting, PLLC
3294 Lantern Coach Lane
Roswell, GA 30075

Attention: Mr. Joseph F. Wiseman, Jr., P.E.

Subject: Report of Geotechnical Analysis - Phase 6 C&D
Buncombe County Landfill
Facility Permit Number 1107-CDLF-1998
Alexander, North Carolina
BLE North Carolina Business License C-1538
BLE Project Number J16-9378-06

Dear Mr. Wiseman

Bunnell-Lammons Engineering, Inc. (BLE) has completed geotechnical analyses of the proposed
Phase 6 expansion of the Buncombe County Construction and Demolition (C&D) Landfill. These
analyses were done in conjunction with the preparation of the Design Hydrogeologic Report by BLE
for the proposed expansion. The purpose of these analyses was generally to evaluate the subgrade
settlement, interim and final waste slope stability, veneer slope stability of closure cover soils, and
provide recommendations for the underdrain drainage system below the north structural fill
embankment.

PROJECT INFORMATION

The subject 654-acre landfill site is located in Buncombe County, North Carolina, approximately
nine miles north of the city of Asheville with a physical address of 81 Panther Branch Road in
Alexander, North Carolina (Appendix A – Figure 1). Buncombe County owns and operates a Subtitle
D municipal solid waste (MSW) landfill which includes Cell 1 through Cell 6 and a C&D landfill
consisting of Phase 1 through Phase 5.

The Phase 6 C&D expansion is to consist of approximately 11.6 acres to be installed east of the
existing Phase 5 C&D waste area. Phase 6 waste will be tied-into the existing Phase 5 waste slopes.
The C&D waste fill within Phase 6 will be approximately 740,000 cy.

An earthen embankment will form the northern boundary between Phase 6 and the existing Sediment
Basin 13 (S.B. 13). The embankment will be approximately 44 feet in height along the existing
sloping topography, with a width from 60 feet at the toe of the embankment to 140 feet at the edge
of the Phase 6 waste limits.

The waste subgrade has been designed to a maximum inclination of 2.5H:1V and minimum of
5H:1V. An HDPE underdrain is planned to be installed in the location of the existing ephemeral
stream.

Report of Geotechnical Analysis September 21, 2017
Buncombe County Landfill BLE Project No. J16-9378-06
Alexander, North Carolina

2

North Carolina Department of Environmental Quality (NCDEQ) rule NCAC 15A 13B.0540(2a)
requires a minimum of 4 feet be maintained between the post settlement bottom elevation of waste
and bedrock, as established by the Design Hydrogeological Report. Based on approval by NCDEQ,
a potential variation in the seasonal high water level has been accounted for in the design of the waste
subgrades, which requires that a minimum of 5.6 feet be maintained between the post settlement
bottom elevation of waste and the variable seasonal high water level. The 5.6 feet correction factor
was calculated by BLE in a report titled Report of Analysis of Correction Factors for Seasonal High Groundwater Elevations, Buncombe County Landfill, Alexander, North Carolina, dated July 14, 2017.

The upper two feet of the waste subgrade is to consist of SC, SM, ML, CL, MH, or CH soils.

SITE GEOLOGY AND SUBSURFACE CONDITIONS

This report was produced in conjunction with the Phase 6 Design Hydrogeologic Report (DHR). Our
knowledge of the site’s geology and subsurface conditions are based on the Phase 6 DHR as well as
from our past site experience, from the records of prior ground water well installations and from auger
borings performed for the Phase 5 DHR by Camp, Dresser & McKee (CDM) (2009).

The site subsurface conditions are summarized below for the purposes of this geotechnical
evaluation. The reader is referred to the Hydrogeologic Assessment Report for a more detailed
description and to view specific boring records and laboratory test data.

SITE GEOLOGY

Topographically, the ground surface elevation in the Phase 6 area drops off into a north-northwest
trending ravine from a ridgeline located on the south side of Phase 6. The highest elevation in the
Phase 6 footprint is approximately 2080 feet above mean sea level (msl) located at the south-central
Phase 6 boundary, and the lowest elevation is approximately 1910 feet msl located at the northern
Phase 6 boundary. The relief across the Phase 6 area is approximately 170 feet.

Groundwater in the Phase 6 area generally flows from the southern ridgeline towards the north-
northwest into an unnamed tributary to Panther Branch which discharges to the French Broad River.

The Phase 6 footprint is underlain by saprolite soils, partially weathered rock, and bedrock at depth.
The saprolite soils are the result of in-place weathering of the gneiss bedrock, and consists of brown,
slightly micaceous, silty fine to coarse sand with lesser amounts of sandy silt and sandy clay. Where
encountered, the thickness of the soil component ranges from 3.0 to 35.0 feet below ground surface
with an average thickness of 9.3 feet. USCS classifications of these soils are typically SM and SC,
and less commonly CL. N-values ranged from 4 to 85 with an average value of 19.8, indicating a
firm average consistency.

The boundary between soil and rock is not sharply defined. A transitional zone of partially weathered
rock is normally found overlying the parent bedrock. Partially weathered rock is defined, for
engineering purposes, as residual material with standard penetration resistance in excess of 100
blows per foot (bpf). Fractures, joints, and the presence of less resistant rock types facilitate

Report of Geotechnical Analysis September 21, 2017
Buncombe County Landfill BLE Project No. J16-9378-06
Alexander, North Carolina

3

weathering. Consequently, the profile of the partially weathered rock and hard rock is quite irregular
and erratic, even over short horizontal distances. Also, it is not unusual to find lenses and boulders
of hard rock and zones of partially weathered rock within the soil mantle, well above the general
bedrock level. Site PWR material consisted primarily of gray and brown, micaceous silty and clayey
fine to medium sand with gravel in some locations. Where encountered, this zone was found to range
in thickness from 3.0 to 20.5 feet, with an average thickness of 9.9 feet.

The upper bedrock profile is fractured, severely to slightly weathered, feldspar-quartz-hornblende
gneiss. Alternating rock seams and partially weathered rock zones were commonly encountered in
the rock core samples. The metamorphic foliation is moderately to steeply dipping and the bedrock
fractures (joints) are moderately to steeply dipping. In general, the bedrock becomes more competent
with depth.

Groundwater in the Phase 6 area follows a north-northwest trending drainage feature towards
Sediment Pond No. 13. Beyond Sediment Basin No. 13 to, groundwater flows and discharges to the
north-northwest trending drainage feature and to westward flowing Panther Branch. The
groundwater table surface has a configuration similar to the site topography. Recharge to the
unconfined aquifer occurs at the higher elevations of Phase 6 and in the areas south of Phase 6.
Accounting for the 5.6 correction to the groundwater elevation, the groundwater is located 6 to 77
feet below the current ground surface within the limits of Phase 6, with the shallower depths located
at the north edge of Phase 6 near Sediment Basin No. 13.

SUMMARY OF EVALUATION

Analysis of the stability of components of the landfill was performed by BLE and in general consisted
of the components of the landfill overlying the liner system as well as settlement of the landfill
subgrade.

The analysis performed by BLE consisted of evaluation of the following components:
(1) stability of proposed final C&D waste slopes,
(2) veneer sliding stability of the closure cap,
(3) subgrade settlement resulting from the full future height of the landfill, and
(4) drainage requirements for the northern embankment and underdrain.

Our evaluation was based upon review of the subsurface data and the proposed initial and finished
surface grading plans provided by McGill Associates.

Stability of Final C&D Waste Slopes: The analysis included the final north C&D waste and cap
grades, as represented by Cross Section A-A, and the west temporary interim waste slopes as
represented by Cross Section B-B. The Draft Alignments and Cross Sections A-A and B-B were
provided by McGill Associates. The Plan and Cross Section view of A-A and B-B are displayed on
the Draft McGill Sheets C-101 CDLF Phase 6 Preliminary Site Layout, Draft C-107 Cross Section A-A, and Draft C-108 Cross Section B-B, dated June 2017 (Appendix A). Static stability analyses
were performed using the computer program Slope/W by Geo-Slope International. Both circular and
block failure modes were considered. Analysis of potential interface sliding (or, translational sliding)
along the waste to soil subgrade and soil subgrade to bedrock interface were considered. The shear

Report of Geotechnical Analysis September 21, 2017
Buncombe County Landfill BLE Project No. J16-9378-06
Alexander, North Carolina

4

strengths for the various layer materials used in the analyses were obtained from laboratory testing
of undisturbed and remolded representative samples of site soils, published relationships between
index testing and soil shear strengths, and published strength parameters for waste. Global stability,
waste slope stability, and sliding block interface potential failure modes were analyzed for the waste
mass. The local stability of the proposed earthen embankment forming the northern boundary of
Phase 6 and adjacent to S.B. 13 was analyzed as well. A factor of safety of 1.5 or more is considered
acceptable for long term (steady state) static conditions.

The proposed northern and southern final 3H:1V waste grades of the C&D waste slope represented
by Alignment A-A achieved the minimum recommended F.S. > 1.5 under the assumptions for
circular and translations block failure types. The analysis assumes the presence of an underdrain
system capable of capturing the groundwater below the C&D subgrade and northern structural fill
embankment.

The F.S. for Alignment A-A’s waste slope ranged from 1.90 to 2.81 when considering global
stability, waste slope stability, and sliding block interface failure modes which satisfies the minimum
recommended F.S. > 1.5.

The F.S. for Alignment B-B’s waste slope ranged from 2.43 to 3.71 when considering global
stability, waste slope stability, and sliding block interface failure modes which satisfies the minimum
recommended F.S. > 1.5.

The analysis assumes proper bonding between existing C&D wastes and future placed C&D waste
placed to achieve the planned final slope inclination. Suitable bonding of the C&D wastes assumes
the waste has been keyed into the existing waste materials through benching of the existing waste
surfaces, and that softened or weathered waste cover surface soils have been stripped prior to waste
placement. Prior to the placement of C&D wastes above the soil subgrade, the soil subgrade is to be
maintained in its final constructed condition (e.g. well compacted, without excess moisture or
softening due to moisture) until C&D waste is placed.

The analysis assumes that no excess pore pressure will be present within the C&D waste mass of
Phase 6. The full results of the global stability analyses are presented in the “Calculation
Documentation – Slope Stability Analysis” Appendix B to this report.

Veneer Sliding Stability: The sliding resistance for the planned cap system was analyzed using the
Koerner method for finite length slopes. The loading evaluated for the waste and cap interface
consisted of the 18-inch thickness of soil cover with 18-inch thickness topsoil (3 feet total) on the
designed maximum 676-foot slope length. The calculations presented in Appendix C indicate that
the cap system has a factor of safety of 1.5 or greater against sliding when provided with an interface
friction resistance, (combination of adhesion and friction angle) equivalent to a peak interface friction
angle of 27.5 degrees for the 3H:1V cap slope.

Subgrade Settlement: An evaluation of potential settlements of the planned subgrade soils when
subjected to the proposed waste loads from the combined existing and planned future expanded
landfill grades was performed. Compressibility parameters for the soil profile were estimated based
on published correlations with standard penetration resistance and soil types and our experience. The
subgrade settlement was estimated at each boring location performed within the planned Phase 6

Report of Geotechnical Analysis September 21, 2017
Buncombe County Landfill BLE Project No. J16-9378-06
Alexander, North Carolina

5

footprint (B-622, B-624D, B-625, and B-801 thru B-806) and at the point of maximum waste and
structural fill thickness (Appendix A, Figure 2, 3, and 4). The settlement calculations performed for
each cell are presented in the “Subgrade Settlement” section of Appendix D of this report. The
maximum total subgrade settlement caused by the planned additional waste loading due to the
expansion is estimated to be approximately 6.3 inches (0.53 feet). The maximum settlement was
found at the point of maximum waste and structural fill thickness, near boring B-804. The settlement
magnitude at any given location will vary with the waste height, the thickness of the subgrade soil
layer overlying rock and the thickness of new structural fill. Subgrade settlements near the perimeter
of the landfill as a result of waste placement are expected to be on the order of 0.3-foot or less.

Groundwater and Bedrock Separation with C&D Waste Subgrade: Based on the furnished planned
subgrade elevations and the estimated subgrade settlement at specific points of interest, the post-
settlement separation between the bottom of the C&D waste subgrade and the seasonal high groundwater
elevation will range from 11.04 to 37.16 feet. The seasonal high groundwater assumed a correction
factor of 5.6 feet based on the aforementioned July 2017 report by BLE.

The post-settlement separation between the bottom of C&D waste subgrade and bedrock ranges from
4.00 to 22.84 feet. Documentation of the post-settlement separation of the C&D waste subgrade with
the seasonal high groundwater level and bedrock are presented in Appendix D of this report.

Underdrain Recommendations - North Embankment: A drainage and filter flow analysis was
performed for the underdrain system to be installed below the north embankment (Appendix E). The
underdrain is understood to consist of a 2 feet by 2 feet minimum ASTM No. 57 stone channel
encapsulated in a drainage geotextile, with a 6 to 8-inch perforated HDPE pipe acting to transmit flow
and act as a cleanout within the encapsulated channel. The underdrain will be installed along the existing
ephemeral stream running through the northwest portion of Phase 6, and drain from the north
embankment above Sediment Pond No. 13. The stream varies from 2.5H:1V to greater than 4H:1V
inclination.

Based on the drainage analysis, the underdrain cross section of a 2 feet by 2 feet, ASTM No. 57 stone
channel will provide sufficient drainage based on the expected ground water flow. Based on the filter
flow analysis, a 6-osy nonwoven geotextile such as a SKAPS GE-160 (or equivalent) will provide
sufficient permeability to allow for groundwater flow into the underdrain without clogging the fabric
with subgrade soils.

Sediment Basin 13 is expected to have a temporary maximum water height at elevation 1890 feet above
MSL. The base of the northern embankment fill is located near 1886 feet above MSL. In order to prevent
the base of the embankment fill from being damaged by water flow, we recommend the following:

1. The toe of the embankment fill to elevation 1890 consist of ASTM No. 57 stone fill. The stone
fill is to be separated from the existing subgrade soils and overlying fill soils using a 6-osy non-
woven geotextile such as a SKAPS GE-160 (or equivalent). The outside portion of the stone fill
should is to be overlain with a layer of rip rap stone.

2. The underdrain is to drain from the fill embankment at or above elevation 1890, rather than at
the toe of the embankment slope. This will allow for the underdrain to continue to drain
groundwater flow in the temporary event that Sediment Basin No. 13 is in a full condition.

APPENDICES
Appendix A: Figures
Appendix B: Slope Stability Analysis
Appendix C: Veneer Sliding Stability
Appendix D: Subgrade Settlement / Groundwater & Bedrock
Separation with C&D Waste Subgrade
Appendix E: Drainage Layer Analysis / Selection of Nonwoven
Geotextile for Drain

APPENDIX A

FIGURES
2
3
4
SOIL
ROA
D
SOIL ROADSOILROADGRAVEL
GRAVEL
MW
EXIST.
SOIL
ROAD
GRAVEL
ROAD
A
B
OUTLET
GRATE 1886.5'
INV OUT 1877.5'
B-801
B-802
B-803
B-804
B-805
B-806
B-807
B-808
DEEP
B-808
SHALOW
PROPOSED 24-FOOT GRAVEL ACCESS ROAD
POTENTIAL FUTURE GRAVEL ACCESS ROAD
EXISTING ACCESS ROAD TO BE IMPROVED
TO ACCOMMODATE FUTURE LANDFILL ACCESS AND
TO PROVIDE ACCESS TO S.B. 13 AND LOWER LEVEL
OF PROPOSED CDLF PHASE 6
POTENTIAL FUTURE TOP OF CAP ELEVATIONS
PROPOSED 20-FOOT GRAVEL ACCESS ROAD
GRAVEL TO BE REMOVED PRIOR TO WASTE FILL IN ROAD AREA
PROPOSED CDLF PHASE 6 TOP OF CAP ELEVATION, TYP.
10-FOOT DRAINAGE TERRACE CONSTRUCTED INTO CAP AT NO GREATER THAN 70 VERTICAL FEET
TACK-ON DRAINAGE BERMS ADDED AT 35-FOOT INTERVALS (NOT SHOWN HERE)
PROPOSED TACK-ON DRAINAGE BERM AT BASE GRADES OF LANDFILL, TYP.
INSTALL AT MAX. 4% SLOPE, EXTEND TO DITCH AT PERIPHERY OF CELL
DRAINAGE BERM TO BE REMOVED PRIOR TO WASTE FILL
MAINTAIN ACCESS TO EXISTING GRAVEL ROAD FOR AS LONG AS
POSSIBLE DURING THE FILLING OPERATION OF CDLF PHASE 6POTENTIAL STORM DRAINAGE PIPE, TYP.
PROPOSED EARTHEN EMBANKMENT - TOP IS MIN. 20-FOOT WIDTH
SLOPE EMBANKMENT EAST AND WEST AT 3%
TO REMOVE RUNOFF TO PERIPHERAL DITCHES
PROPOSED ARMORED PERIPHERAL DRAINAGE DITCH
PROPOSED WASTE LIMITS
NEW LANDFILL AREA: 10.0 ACRES
CDLF PH 6 (INCLUDING AREA OVER EXISTING CDLF): 11.6 ACRES
PROPOSED CDLF PHASE 6 BASE ELEVATION, TYP. - MAX. SLOPE 2.5:1
INSTALL PERFORATED 18" HDPE UNDERDRAIN BENEATH BASE GRADES IN AREA OF EPHEMERAL STREAM (UNDERDRAIN NOT SHOWN)
VERIFY THAT SOILS IN TOP 2-FEET OF LANDFILL BASE MEET THE REQUIREMENTS OF THE SOLID WASTE RULES
PROPOSED DRAINAGE PIPE TO BE GROUTED PRIOR TO WASTE FILL
OPERATIONS NEAR PIPE
ORIGINAL CDM WASTE LIMITS
APPROXIMATE EXISTING WASTE LIMITS
FIELD VERIFICATION REQUIRED
EXISTING CDLF
EXISTING SOIL BORROW AREA
EXIST.
SOIL
ROAD
EXIST.
SOIL
ROAD
EXIST.
SOIL
ROAD
EXIST.
SOIL
ROAD
EXIST.
GRAVEL
ROAD BUNCOMBE COUNTY LANDFILLBUNCOMBE COUNTY, NORTH CAROLINABUNCOMBE COUNTYCDLF PHASE 6DP17.00701JUNE 2017DPCDLF PHASE 6PRELIMINARY SITE LAYOUTSHEETDESIGN REVIEW: _____DESIGNED BY:JOB NO.:DATE:CADD BY:CONST. REVIEW: _____/E) NKNNO. DATE BY REVISION DESCRIPTION FILE NAME: BuncCo CDLF Ph 6Preliminary Site Plan6-26-17.dwgPLAN
+0%*(''6)4#2*+%5%#.'
  

PERMIT TO CONSTRUCTDRAFT
ElevationElevation1910.00
1920.00
1930.00
1940.00
1950.00
1960.00
1970.00
1980.00
1990.00
2000.00
2010.00
2020.00
2030.00
2040.00
2050.00
2060.00
2070.00
2080.00
2090.00
2100.00
2110.00
2120.00
2130.00
1910.00
1920.00
1930.00
1940.00
1950.00
1960.00
1970.00
1980.00
1990.00
2000.00
2010.00
2020.00
2030.00
2040.00
2050.00
2060.00
2070.00
2080.00
2090.00
2100.00
2110.00
2120.00
2130.00
10+00.00 11+00.00
12+00.00
13+00.00 14+00.00 15+00.00 16+00.00 17+00.00 18+00.00 19+00.00 20+00.00
GROUNDWATER ELEVATIONS FROM DRAFT DHR JUNE 2017PRELI
MI
N
A
R
Y
B
A
S
E
G
R
A
D
E

E
L
E
V
A
TI
O
N
S
PRELIMINARY TOP OF CAP ELEVATIONSEXISTING GROUND ELEVATIONSFROM ED HOLMES SURVEYINCLUDES 5.6' CORRECTION FACTORCONSTRUCTED DRAINAGE TERRACE, TYP.
MAX. 70 VERTICAL FEET SPACING
INSTALL TACK-ON DRAINAGE TERRACE, TYP.
BETWEEN CONSTRUCTED TERRACES
MAX. 70 VERTICAL FEET SPACING
,167$//81'(5'5$,1$/21*(;,67,1*(3+(0(5$/675($0“/)
PIPE NOT SHOWN HERE
PROPOSED DRAINAGE PIPE TO REMAIN IN SERVICE FOR AS LONG AS POSSIBLE DURING INITIAL PHASES OF LANDFILL DEVELOPMENT
GROUT IN PLACE PRIOR TO WASTE PLACEMENT IN THE VICINITY OF THE UPSTREAM INVERT
SECTION A-A
SCALE
HOR.: 1" = 50'
VER.: 1" = 10'WASTE LIMITSWASTE LIMITSACCESS ROADWASTE FILL
TOP 2-FEET OF SUBGRADE MUST MEET SOIL CLASSIFICATIONS NOTE IN SOLID WASTE RULES
OVEREXCAVATE SOILS AS NECESSARY AND PLACE 2-FEET OF CORRECT SOILS, TYP.BERMBEDR
O
C
K
E
L
E
V
A
TI
O
N
S
FROM
D
R
A
F
T
D
H
R
J
U
N
E
2
0
1
7
NOTE:
MAINTAIN 4' MIN. SEPARATION FROM THE POST-SETTLEMENT
BASEGRADE ELEVATIONS TO BEDROCK OR GROUNDWATER
3 (MAX.)
1
ACCESS ROAD2.5(MAX.)
1
BUNCOMBE COUNTY LANDFILLBUNCOMBE COUNTY, NORTH CAROLINABUNCOMBE COUNTYCDLF PHASE 6DP17.00701JUNE 2017DPCROSS-SECTION A-ASHEETDESIGN REVIEW: _____DESIGNED BY:JOB NO.:DATE:CADD BY:CONST. REVIEW: _____/E) NKNNO. DATE BY REVISION DESCRIPTION FILE NAME: 17.00701 CDLF Ph6-PTC-Cross Sections7-28-17.dwgPERMIT TO CONSTRUCTDRAFT
ElevationElevationStation
Station
2010.00
2020.00
2030.00
2040.00
2050.00
2060.00
2070.00
2080.00
2090.00
2100.00
2110.00
2120.00
2130.00
2140.00
2150.00
2010.00
2020.00
2030.00
2040.00
2050.00
2060.00
2070.00
2080.00
2090.00
2100.00
2110.00
2120.00
2130.00
2140.00
2150.00
-2+00.00 -1+00.00 0+00.000+00.00 1+00.00 2+00.00 3+00.003+03.04 4+00.00 5+00.00 6+00.00 7+00.00 8+00.00 9+00.00 10+00.00 11+00.00 12+00.00
-2+00.00 -1+00.00 0+00.00
0+00.00
1+00.00 2+00.00 3+00.00
3+03.04
4+00.00
4+62.04
5+00.00 6+00.00 7+00.00 8+00.00 9+00.00
9+05.02
10+00.00 11+00.00 12+00.00
SECTION B-B
SCALE
HOR.: 1" = 50'
VER.: 1" = 10'WASTE LIMITSACCESS ROADEXISTING CDLF PH 5 WASTE LIMITSWASTE FILL
EXISTING
CDLF PHASE 5
WASTE FILL
EXISTING ACCESS ROADGROU
N
D
W
A
T
E
R

E
L
E
V
A
TI
O
N
S
F
R
O
M

D
R
A
F
T
D
H
R
J
U
N
E
2
0
1
7
INCL
U
D
E
S
5.
6'
C
O
R
R
E
C
TI
O
N
F
A
C
T
O
R
BEDR
O
C
K
E
L
E
V
A
TI
O
N
S
FRO
M
D
R
A
F
T
D
H
R
J
U
N
E
2
0
1
7
PERMITTED FUTURE CDLF PHASE 5 CAP
INSTALL TACK-ON DRAINAGE TERRACE, TYP.
BETWEEN CONSTRUCTED TERRACES
MAX. 70 VERTICAL FEET SPACING
3 (MAX.)
1
CONSTRUCTED DRAINAGE TERRACE, TYP.
MAX. 70 VERTICAL FEET SPACING
2.5(MAX.)
1
NOTE:
MAINTAIN 4' MIN. SEPARATION FROM THE POST-SETTLEMENT
BASEGRADE ELEVATIONS TO BEDROCK OR GROUNDWATER
EXISTING GROUND ELEVATIONS
FROM ED HOLMES SURVEY
PRELIMINARY BASEGRADE ELEVATIONS
,167$//81'(5'5$,1$/21*(;,67,1*(3+(0(5$/675($0“/)
PIPE NOT SHOWN HERE BUNCOMBE COUNTY LANDFILLBUNCOMBE COUNTY, NORTH CAROLINABUNCOMBE COUNTYCDLF PHASE 6DP17.00701JUNE 2017DPCROSS-SECTION B-BSHEETDESIGN REVIEW: _____DESIGNED BY:JOB NO.:DATE:CADD BY:CONST. REVIEW: _____/E) NKNNO. DATE BY REVISION DESCRIPTION FILE NAME: 17.00701 CDLF Ph6-PTC-Cross Sections7-28-17.dwgPERMIT TO CONSTRUCTDRAFT

APPENDIX B
SLOPE STABILITY ANALYSIS
Calculation Documentation –Slope Stability Analysis August 30, 2017
Buncombe County Landfill BLE Project No. J16-9378-06
Alexander, North Carolina

2

PURPOSE

1. Analyze the global slope stability of the C&D waste mound, structural fill, and subgrade
slopes for the proposed Phase 6 grades using Cross Sections A-A & B-B, provided by
McGill Associates..
2. A minimum static factor of safety (F.S.) > 1.5 is recommended for all conditions and
required for the final and intermediate slope configuration.

DESCRIPTION OF ANALYSIS

General Conditions
1. Historic laboratory testing and geotechnical soil test boring with rock coring logs
performed for the Camp, Dresser & Mckee (CDM) produced reports were available to us
for our analysis. The data provided to us came from the following CDM reports: Proposed
Phase 1 Construction and Demolition Landfill Expansion (2002), Phase 4 Buncombe
County Construction and Demolition Landfill Expansion (2005), and Phase 5 Site
Hydrogeologic Investigation (2009).
2. BLE has performed the Design Hydrogeologic Report (DHR) for Phase 6 concurrently
with this analysis. The groundwater information and subsurface profiles were therefore
available for our use.
3. As a part of the Design Hydrogeologic Report scope by BLE, nine groundwater monitoring
wells were installed. Geotechnical soil test borings with rock coring were performed at the
time of the well installations. Laboratory testing was performed on split spoon, bulk, and
undisturbed Shelby tube samples, and included grain size and Atterberg limits, hydraulic
conductivity, standard proctor density, hydraulic conductivity, and consolidated undrained
triaxial testing.
4. McGill Associates provided Cross Sections A-A and B-B, which were used for the
analysis. Draft Figures were provided by McGill Associates for our analysis, and included
Sheet C-101 CDLF Phase 6 Preliminary Site Layout, Sheet C-107 Cross Section A-A, and
Sheet C-108 Cross Section B-B, dated June 2017. BLE reviewed the 2 cross sections and
confirmed that the McGill Associates-produced cross sections are the apparent critical
cross sections for the purpose of slope stability analysis.
a. Current grades within the currently permitted C&D waste limits were from a
topographic survey conducted by Ed Holmes Surveying, March 2017.
b. Existing grades outside of permitted C&D waste limits is a compilation of past
topographic surveys (dates not provided).
c. The proposed 3:1 H:V final cap grades, Phase 6 C&D waste grades, and base
grades of Phase 6 were provided by McGill Associates
Calculation Documentation –Slope Stability Analysis August 30, 2017
Buncombe County Landfill BLE Project No. J16-9378-06
Alexander, North Carolina

3

5. Groundwater levels for effective stress slope stability modeling are based on the
Potentiometric Contour Map presented in the Draft Design Hydrogeologic Report by
Bunnell-Lammons Engineering dated June 2017. The groundwater levels shown
conservatively include a 5.6 feet correction factor based on recommendations in BLE’s
DHR.
6. Bedrock elevations are based on the borings performed for the scope of this and the Draft
Design Hydrogeologic Report by Bunnell-Lammons Engineering dated June 2017.
7. The subsurface of the landfill is to consist of the following layers, from the top of subgrade
down:
a. Where necessary, the existing topography will raised to design grades using onsite
structural fill. Structural fill soils on the site will consist of excavated residual
clayey and silty sands. The thickest structural fill areas will require approximately
9 feet of fill to achieve the proposed design subgrade.
b. A layer of residual, fine to coarse silty sand and sandy silt and clay. The layer
ranges from 3 to 8 feet thick within the subgrade of Phase 6 prior to grading.
c. A layer of partially weathered rock (PWR) generally ranging from 6.5 to 20.5 feet
thick below Phase 6. Near the north toe of Phase 6, PWR thins out to negligible
thickness.
d. A bedrock layer. The bedrock on site has been previously classified from rock
cores as slightly to very fractured, foliated undifferentiated Gneiss with quartz
biotite, feldspar, horneblende, and mica. A minimum of 4-feet of soil buffer is to
be in place between the waste subgrade and the bedrock layer.
8. Shear strengths of the underlying residual material and PWR were conservatively assumed
based on typical values for sand and silty sand, SPT N-values from the historic and current
soil test borings, and historic lab testing performed in the reports by CDM.
9. Shear strength of the C&D waste was estimated from published literature and our previous
experience with similar materials.
10. Shear strength of the proposed structural fill sandy and silty sands is based on laboratory
triaxial shear strength testing performed as part of the Phase 6 DHR.

Assumptions
1. The analysis assumes proper bonding between C&D waste and soil subgrades, and between
all C&D waste fills.
a. Bonding between existing C&D wastes and future placed C&D fills placed to
achieve the planned final slope inclination is assumed. Suitable bonding of the
C&D wastes assumes the waste has been keyed into the existing waste materials
through benching of the existing waste surfaces, and that softened or weathered
waste cover surface soils have been stripped prior to waste placement.
Calculation Documentation –Slope Stability Analysis August 30, 2017
Buncombe County Landfill BLE Project No. J16-9378-06
Alexander, North Carolina

4

b. Prior to the placement of C&D wastes above the soil subgrade, the soil subgrade
is to be maintained in its final constructed condition (e.g. well compacted, without
excess moisture or softening due to moisture) until C&D waste is placed.
2. The analysis assumes the C&D waste is fully draining, and does not have a piezometric
head within the waste.
3. The analysis calculated the factors of safety for the design Phase 6 C&D waste grades and
for the revised final cap grades provided by McGill Associates. The final grades are at a
3:1 (H:V) inclination, with three, approximately 10-feet wide drainage terraces. A
maximum inclination of 2.5:1 (H:V) is maintained within the base grades.
4. A structural fill embankment is to be constructed at the northern, lower end of Phase 6
above Sediment Basin 13. An underdrain is to be installed below the subgrade of the
embankment to allow for drainage of groundwater to Sediment Basin 13. As such, the
groundwater is modeled accounting for the drainage effect to keep the groundwater below
the embankment.
5. Based on the maximum elevation of the Basin’s outer fill and discussions with McGill
Associates, the maximum water elevation modeled within Sediment Basin 13 is 1890 feet.

The analysis was performed using SLOPE/W of the GeoStudio 2016 software package (August
2016 Release, Version 8.16.4.14710) developed by GEO-SLOPE International. The analysis used
the Morgenstern-Price method of slices for limit equilibrium, using an Entry/Exit (circular failure)
block specified (block failure), or fully specified (block composite) slip surface search criteria. In
general, the program calculates the factor of safety along trial slip surface locations by calculating
the available shear resistance and the shear resistance required to satisfy force and moment
equilibrium.

The following table outlines the estimated Mohr-Coulomb shear strength envelopes utilized for the
various materials and conditions:

Table 1: Shear Strength Parameters
Material
Unit Weight
(pcf)
Friction Angle,
ϕ (º)
Cohesion,
c (psf)
Bedrock Impenetrable
Partially Weathered Rock (PWR) 125 35 500
Residual Soils 125 31 0
Structural Fill 120 29.5 150
C&D Waste 75 30 200
Calculation Documentation –Slope Stability Analysis August 30, 2017
Buncombe County Landfill BLE Project No. J16-9378-06
Alexander, North Carolina

5

SUMMARY OF RESULTS

The following tables summarizes the minimum slope stability factors of safety results for Cross
Sections A-A and B-B:

Table 2A: Minimum Slope Stability Factors of Safety for Alignment A-A, Phase 6 Northwest
& South Slope
MODEL
NO.
MODEL
NAME
FAILURE
LOCATION NOTES FAILURE
SHAPE
LOWEST
MINIMUM
F.S.
1A4
Structural
Fill Outer
Embankment
Structural Fill
Embankment
Slope
Assumes Full S.B.
13 (Elev. 1890 feet),
with Toe Drain
Circular
(Optimized) 1.56
1A5
Structural
Fill Outer
Embankment
Structural Fill
Embankment
Slope
Assumes drained
S.B. 13 with Toe
Drain
Circular
(Optimized) 1.51
2A2
Global
Failure -
Bottom
Global Failure Circular
(Optimized) 1.90
2A3
Global
Failure -
Total Slope
Global Failure Circular
(Optimized) 1.98
3A C&D Waste Within C&D
Waste Circular
(Optimized) 2.18
4A3
Sliding
Block
Failure -
Waste
Sliding C&D
Above
Subgrade
Translational 2.21
4A4
Sliding
Block
Failure -
Subgrade
Sliding C&D
and Subgrade
Above
Bedrock
Translational 2.64
5A1
Global
Failure -
South Slope
South Slope
of Phase 6
Within C&D
Waste
Circular
(Optimized) 2.81

Calculation Documentation –Slope Stability Analysis August 30, 2017
Buncombe County Landfill BLE Project No. J16-9378-06
Alexander, North Carolina

6

Table 2B: Minimum Slope Stability Factors of Safety for Alignment B-B, Phase 6 West Slope
MODEL
NO.
MODEL
NAME
FAILURE
LOCATION
FAILURE
SHAPE
LOWEST
MINIMUM
F.S.
1A Lower
Slope
Toe of Slope Waste
& Gravel Road
Circular
(Optimized) 2.58
2A2
Global
Failure -
Bottom
Global Failure - Toe
of Slope to Crest
Circular
(Optimized) 2.43
3A C&D
Waste Within C&D Waste Circular
(Optimized) 2.48
4A3
Sliding
Block
Failure -
Waste
Sliding C&D Above
Subgrade Translational 2.64
4A4
Sliding
Block
Failure -
Subgrade
Sliding C&D and
Subgrade Above
Bedrock
Translational 3.71

The proposed northern and southern final 3H:1V waste grades of the C&D waste slope represented
by Alignment A-A achieved the minimum recommended F.S. > 1.5 under the assumptions for
circular and translations block failure types.

The proposed west 3H:1V waste grades of the C&D waste slope represented by Alignment B-B
achieved the minimum recommended F.S. > 1.5 for circular and translations block failure types.

CONCLUSION

A global slope stability analysis was performed for the proposed C&D waste slopes of Phase 6 at
the Buncombe County Landfill. The analysis used the McGill Associates provided Alignments A-
A and B-B cross sections, and examined the final planned (3:1) H:V northern, southern, and
western waste slopes.

The recommended static factor of safety of F.S. > 1.5 was achieved for the final waste slope
conditions with the inclusion of a subsurface underdrainage below the northern structural fill
embankment to allow for drainage of potential groundwater to the toe of the embankment.

Calculation Documentation –Slope Stability Analysis August 30, 2017
Buncombe County Landfill BLE Project No. J16-9378-06
Alexander, North Carolina

7

These factors of safety are contingent upon the conditions included in this analysis and presented
in the attached report.

REFERENCES

Bunnell-Lammons Engineering. (2017). Report of Slope Stability Analysis - Phase 5 Expansion
B. Greenville, SC: Bunnell-Lammons Engineering.
Camp Dresser & McKee (CDM). (2002). Proposed Phase 1 Construction and Demolition
Landfill Expansion. Raleigh, NC: CDM .
Camp Dresser & McKee (CDM). (2005). Phase 4 Buncombe County Construction and
Demolition Landfill Expansion. Raleigh, NC: CDM.
Camp Dresser & McKee (CDM). (2009). Phase 5 Site Hydrogeologic Investigation. Raleigh, NC:
CDM.
Duncan, J. M., Wright, S. G., & Brandon, T. L. (2014). Soil Strength and Slope Stability, 2nd
Edition. New Jersey: John Wiley & Sons, Inc.
GEO-SLOPE International. (2016, August). GeoStudio 2016, August 2016 Release, Version
8.16.2.14053. Calgary, Alberta, Canada.
US Army Corps of Engineers. (2003). Engineering and Design: Slope Stability EM 1110-2-1902.
1A4 Structural Fill Outer
Berm
Structural Fill Berm Slope Above
S.B. 13
Assumes Full S.B. 13 (Elev. 1890 feet),
with Toe Drain in Structural Fill Berm
Circular
(Optimized)1.56
1A5 Structural Fill Outer
Berm
Structural Fill Berm Slope Above
S.B. 13
Assumes drained S.B. 13 with Toe Drain in
Structural Fill Berm
Circular
(Optimized)1.51
2A2 Global Failure -
Bottom
Global Failure - Toe of Structural
Fill Berm into C&D Wastes
Circular
(Optimized)1.90
2A3 Global Failure - Total
Slope
Global Failure - Toe of Structural
Fill Berm to Top of Slope
Circular
(Optimized)1.98
3A C&D Waste Within C&D Waste Circular
(Optimized)2.18
4A3 Sliding Block Failure -
Waste Sliding C&D Above Subgrade Translational 2.21
4A4 Sliding Block Failure -
Subgrade
Sliding C&D and Subgrade Above
Bedrock Translational 2.64
5A1 Global Failure - South
Slope
South Slope of Phase 6
Within C&D Waste
Circular
(Optimized)2.81
1A Lower Slope Toe of Slope Waste & Gravel Road Circular
(Optimized)2.58
2A2 Global Failure -
Bottom
Global Failure - Toe of Slope to
Crest
Circular
(Optimized)2.43
3A C&D Waste Within C&D Waste Circular
(Optimized)2.48
4A3 Sliding Block Failure -
Waste Sliding C&D Above Subgrade Translational 2.64
4A4 Sliding Block Failure -
Subgrade
Sliding C&D and Subgrade Above
Bedrock Translational 3.71
MODEL
NO.MODEL NAME
ALIGNMENT A-A (NORTHWEST TO SOUTH, PHASE 6)
SLOPE STABILITY ANALYSIS SUMMARY
BUNCOMBE COUNTY LANDFILL
BUNCOMBE COUNTY, NORTH CAROLINA
BLE Project No. J16-9378-06
PHASE 6 - C&D DHR
FAILURE LOCATION LOWEST MINIMUM F.S.
[PASSING > 1.5 STATIC]
FAILURE
SHAPENOTES
Notes:
(1): Stability was analyzed for circular and translational (block) failure modes and optimized.
(2): Alignments A-A and B-B cross sections used for stability analysis provided by McGill Associates, dated July 28, 2017.
ALIGNMENT B-B (WEST SLOPE PHASE 6 TO EAST EXISTING PHASE 5 C&D WASTE)
MODEL
NO.MODEL NAME FAILURE LOCATION FAILURE
SHAPE
LOWEST MINIMUM F.S.
[PASSING > 1.5 STATIC]NOTES
1
1.56
900 1,000 1,100 1,200 1,300 1,400 1,500 1,600 1,700 1,800 1,900 2,000ELEVATION (FT ABOVE MSL)1,860
1,880
1,900
1,920
1,940
1,960
1,980
2,000
2,020
2,040
2,060
2,080
2,100
2,120
2,140
S.B. 13
BLE
Comments: Cross Section A-A - Buncombe County Landfill C&D Waste Phase 6
As provided by McGill Associates, Figure C-107, June 2017
Created By: Larry Simonson
Date: 8/30/2017
Tool Version: 8.16.4.14710
File Name: Sect A-A.gsz
Name: 1A4-Structural Fill Outer Berm
Description: Failure Limited to Lower Structural Fill Outer Berm
Assumed S.B. 13 full
(1890 ft elevation)
Assumes Toe Drain in Structural Fill Berm
Effective Drained Strengths
Method: Morgenstern-Price
Slip Surface Option: Entry and Exit
Color Name Piezometric
Line
Unit
Weight
(pcf)
Cohesion'
(psf)
Phi'
(°)
Bedrock 1
C&D Waste 1 75 200 30
Partially Weathered
Rock (PWR) (Effective)
1 125 500 35
Residual Soils - Sand
and Silts (Effective)
1 125 0 31
Structurall Fill
(Effective)
1 120 150 29.5
1.51
900 1,000 1,100 1,200 1,300 1,400 1,500 1,600 1,700 1,800 1,900 2,000ELEVATION (FT ABOVE MSL)1,860
1,880
1,900
1,920
1,940
1,960
1,980
2,000
2,020
2,040
2,060
2,080
2,100
2,120
2,140
S.B. 13
BLEComments: Cross Section A-A - Buncombe County Landfill C&D Waste Phase 6
As provided by McGill Associates, Figure C-107, June 2017
Created By: Larry Simonson
Date: 8/30/2017
Tool Version: 8.16.4.14710
File Name: Sect A-A.gsz
Name: 1A5-Structural Fill Outer Berm
Description: Failure Limited to Lower Structural Fill Outer Berm
Drained SB 13
Assumes Toe Drain in Structural Fill Berm
Effective Drained Strengths
Method: Morgenstern-Price
Slip Surface Option: Entry and Exit
Color Name Piezometric
Line
Unit
Weight
(pcf)
Cohesion'
(psf)
Phi'
(°)
Bedrock 1
C&D Waste 1 75 200 30
Partially Weathered
Rock (PWR) (Effective)
1 125 500 35
Residual Soils - Sand
and Silts (Effective)
1 125 0 31
Structurall Fill
(Effective)
1 120 150 29.5
1.90
900 1,000 1,100 1,200 1,300 1,400 1,500 1,600 1,700 1,800 1,900 2,000ELEVATION (FT ABOVE MSL)1,860
1,880
1,900
1,920
1,940
1,960
1,980
2,000
2,020
2,040
2,060
2,080
2,100
2,120
2,140
S.B. 13
BLEComments: Cross Section A-A - Buncombe County Landfill C&D Waste Phase 6
As provided by McGill Associates, Figure C-107, June 2017
Created By: Larry Simonson
Date: 8/30/2017
Tool Version: 8.16.4.14710
File Name: Sect A-A.gsz
Name: 2A2-Global Failure - Bottom
Description: Global Failure from Waste thru Subgrade
Effective Drained Strengths
Method: Morgenstern-Price
Slip Surface Option: Entry and Exit
Color Name Piezometric
Line
Unit
Weight
(pcf)
Cohesion'
(psf)
Phi'
(°)
Bedrock 1
C&D Waste 1 75 200 30
Partially Weathered
Rock (PWR) (Effective)
1 125 500 35
Residual Soils - Sand
and Silts (Effective)
1 125 0 31
Structurall Fill
(Effective)
1 120 150 29.5
1.98
900 1,000 1,100 1,200 1,300 1,400 1,500 1,600 1,700 1,800 1,900 2,000ELEVATION (FT ABOVE MSL)1,860
1,880
1,900
1,920
1,940
1,960
1,980
2,000
2,020
2,040
2,060
2,080
2,100
2,120
2,140
S.B. 13
BLEComments: Cross Section A-A - Buncombe County Landfill C&D Waste Phase 6
As provided by McGill Associates, Figure C-107, June 2017
Created By: Larry Simonson
Date: 8/30/2017
Tool Version: 8.16.4.14710
File Name: Sect A-A.gsz
Name: 2A3-Global Failure - Total Slope
Description: Global Failure from Waste thru Subgrade
Effective Drained Strengths
Method: Morgenstern-Price
Slip Surface Option: Entry and Exit
Color Name Piezometric
Line
Unit
Weight
(pcf)
Cohesion'
(psf)
Phi'
(°)
Bedrock 1
C&D Waste 1 75 200 30
Partially Weathered
Rock (PWR) (Effective)
1 125 500 35
Residual Soils - Sand
and Silts (Effective)
1 125 0 31
Structurall Fill
(Effective)
1 120 150 29.5
2.18
900 1,000 1,100 1,200 1,300 1,400 1,500 1,600 1,700 1,800 1,900 2,000ELEVATION (FT ABOVE MSL)1,860
1,880
1,900
1,920
1,940
1,960
1,980
2,000
2,020
2,040
2,060
2,080
2,100
2,120
2,140
S.B. 13
BLEComments: Cross Section A-A - Buncombe County Landfill C&D Waste Phase 6
As provided by McGill Associates, Figure C-107, June 2017
Created By: Larry Simonson
Date: 8/30/2017
Tool Version: 8.16.4.14710
File Name: Sect A-A.gsz
Name: 3A-C&D Waste
Description: Failure Limited to C&D Waste
Effective Drained Strengths
Method: Morgenstern-Price
Slip Surface Option: Entry and Exit
Color Name Unit
Weight
(pcf)
Cohesion'
(psf)
Phi' (°) Piezometric
Line
C&D Waste 75 200 30 1
Structurall Fill
(Effective)
120 150 29.5 1
2.21
900 1,000 1,100 1,200 1,300 1,400 1,500 1,600 1,700 1,800 1,900 2,000ELEVATION (FT ABOVE MSL)1,860
1,880
1,900
1,920
1,940
1,960
1,980
2,000
2,020
2,040
2,060
2,080
2,100
2,120
2,140
S.B. 13
BLEComments: Cross Section A-A - Buncombe County Landfill C&D Waste Phase 6
As provided by McGill Associates, Figure C-107, June 2017
Created By: Larry Simonson
Date: 8/30/2017
Tool Version: 8.16.4.14710
File Name: Sect A-A.gsz
Name: 4A3 - Sliding Block Failure - Waste
Description: Sliding Failure of C&D Waste above Subgrade
Effective Drained Strengths
Non-Optimized to force sliding
Method: Morgenstern-Price
Slip Surface Option: Fully-Specified
Color Name Piezometric
Line
Unit
Weight
(pcf)
Cohesion'
(psf)
Phi'
(°)
Bedrock 1
C&D Waste 1 75 200 30
Partially Weathered
Rock (PWR) (Effective)
1 125 500 35
Residual Soils - Sand
and Silts (Effective)
1 125 0 31
Structurall Fill
(Effective)
1 120 150 29.5
2.64
900 1,000 1,100 1,200 1,300 1,400 1,500 1,600 1,700 1,800 1,900 2,000ELEVATION (FT ABOVE MSL)1,860
1,880
1,900
1,920
1,940
1,960
1,980
2,000
2,020
2,040
2,060
2,080
2,100
2,120
2,140
S.B. 13
BLEComments: Cross Section A-A - Buncombe County Landfill C&D Waste Phase 6
As provided by McGill Associates, Figure C-107, June 2017
Created By: Larry Simonson
Date: 8/30/2017
Tool Version: 8.16.4.14710
File Name: Sect A-A.gsz
Name: 4A4 - Sliding Block Failure - Subgrade
Description: Sliding Failure of Subgrade above Bedrock
Non-Optimized to force sliding
Effective Drained Strengths
Method: Morgenstern-Price
Slip Surface Option: Fully-Specified
Color Name Piezometric
Line
Unit
Weight
(pcf)
Cohesion'
(psf)
Phi'
(°)
Bedrock 1
C&D Waste 1 75 200 30
Partially Weathered
Rock (PWR) (Effective)
1 125 500 35
Residual Soils - Sand
and Silts (Effective)
1 125 0 31
Structurall Fill
(Effective)
1 120 150 29.5
2.81
900 1,000 1,100 1,200 1,300 1,400 1,500 1,600 1,700 1,800 1,900 2,000ELEVATION (FT ABOVE MSL)1,860
1,880
1,900
1,920
1,940
1,960
1,980
2,000
2,020
2,040
2,060
2,080
2,100
2,120
2,140
S.B. 13
BLEComments: Cross Section A-A - Buncombe County Landfill C&D Waste Phase 6
As provided by McGill Associates, Figure C-107, June 2017
Created By: Larry Simonson
Date: 8/30/2017
Tool Version: 8.16.4.14710
File Name: Sect A-A.gsz
Name: 5A1-Global Failure - SOUTH SLOPE
Description: Global Failure from Waste thru Subgrade
Effective Drained Strengths
Method: Morgenstern-Price
Slip Surface Option: Entry and Exit
Color Name Piezometric
Line
Unit
Weight
(pcf)
Cohesion'
(psf)
Phi'
(°)
Bedrock 1
C&D Waste 1 75 200 30
Partially Weathered
Rock (PWR) (Effective)
1 125 500 35
Residual Soils - Sand
and Silts (Effective)
1 125 0 31
Structurall Fill
(Effective)
1 120 150 29.5
2.58
STATION
0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900ELEVATION (FT ABOVE MSL)1,970
1,990
2,010
2,030
2,050
2,070
2,090
2,110
2,130
2,150
EXISTING
CDLF PHASE 5PROPOSED CDLF
PHASE 6
BLEComments: Cross Section B-B' - Buncombe County Landfill C&D Waste Phase 6
As Provided by McGill Associates, Figure C-108, June 2017
Created By: Larry Simonson
Date: 8/29/2017
Tool Version: 8.16.4.14053
File Name: Sect B-B.gsz
Name: 1A-Lower Slope
Description: Failure Limited to Lower Slope
Effective Drained Strengths
Method: Morgenstern-Price
Slip Surface Option: Entry and Exit
Color Name Piezometric
Line
Unit
Weight
(pcf)
Cohesion'
(psf)
Phi'
(°)
Bedrock 1
C&D Waste 1 75 200 30
Partially Weathered
Rock (PWR) (Effective)
1 125 500 35
Residual Soils - Sand
and Silts (Effective)
1 125 0 31
Structurall Fill
(Effective)
1 120 150 29.5
2.43
STATION
0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900ELEVATION (FT ABOVE MSL)1,970
1,990
2,010
2,030
2,050
2,070
2,090
2,110
2,130
2,150
EXISTING
CDLF PHASE 5PROPOSED CDLF
PHASE 6
BLE
Comments: Cross Section B-B' - Buncombe County Landfill C&D Waste Phase 6
As Provided by McGill Associates, Figure C-108, June 2017
Created By: Larry Simonson
Date: 8/29/2017
Tool Version: 8.16.4.14053
File Name: Sect B-B.gsz
Name: 2A2-Global Failure - Bottom
Description: Global Failure from Waste thru Subgrade
Method: Morgenstern-Price
Slip Surface Option: Entry and Exit
Color Name Piezometric
Line
Unit
Weight
(pcf)
Cohesion'
(psf)
Phi'
(°)
Bedrock 1
C&D Waste 1 75 200 30
Partially Weathered
Rock (PWR) (Effective)
1 125 500 35
Residual Soils - Sand
and Silts (Effective)
1 125 0 31
Structurall Fill
(Effective)
1 120 150 29.5
2.48
STATION
0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900ELEVATION (FT ABOVE MSL)1,970
1,990
2,010
2,030
2,050
2,070
2,090
2,110
2,130
2,150
EXISTING
CDLF PHASE 5PROPOSED CDLF
PHASE 6
BLEComments: Cross Section B-B' - Buncombe County Landfill C&D Waste Phase 6
As Provided by McGill Associates, Figure C-108, June 2017
Created By: Larry Simonson
Date: 8/29/2017
Tool Version: 8.16.4.14053
File Name: Sect B-B.gsz
Name: 3A - C&D Waste
Description: Failure Limited to C&D Waste
Effective Drained Strengths
Method: Morgenstern-Price
Slip Surface Option: Entry and Exit
Color Name Unit
Weight
(pcf)
Cohesion'
(psf)
Phi'
(°)
Piezometric
Line
C&D Waste 75 200 30 1
Residual Soils - Sand
and Silts (Effective)
125 0 31 1
Structurall Fill
(Effective)
120 150 29.5 1
2.64
STATION
0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900ELEVATION (FT ABOVE MSL)1,970
1,990
2,010
2,030
2,050
2,070
2,090
2,110
2,130
2,150
EXISTING
CDLF PHASE 5PROPOSED CDLF
PHASE 6
BLE
Comments: Cross Section B-B' - Buncombe County Landfill C&D Waste Phase 6
As Provided by McGill Associates, Figure C-108, June 2017
Created By: Larry Simonson
Date: 8/29/2017
Tool Version: 8.16.4.14053
File Name: Sect B-B.gsz
Name: 4A3 - Sliding Block Failure - Waste
Description: Sliding Failure of C&D Waste above Subgrade
Method: Morgenstern-Price
Slip Surface Option: Fully-Specified
Color Name Piezometric
Line
Unit
Weight
(pcf)
Cohesion'
(psf)
Phi'
(°)
Bedrock 1
C&D Waste 1 75 200 30
Partially Weathered
Rock (PWR) (Effective)
1 125 500 35
Residual Soils - Sand
and Silts (Effective)
1 125 0 31
Structurall Fill
(Effective)
1 120 150 29.5
3.71
STATION
0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900ELEVATION (FT ABOVE MSL)1,970
1,990
2,010
2,030
2,050
2,070
2,090
2,110
2,130
2,150
EXISTING
CDLF PHASE 5PROPOSED CDLF
PHASE 6
BLEComments: Cross Section B-B' - Buncombe County Landfill C&D Waste Phase 6
As Provided by McGill Associates, Figure C-108, June 2017
Created By: Larry Simonson
Date: 8/29/2017
Tool Version: 8.16.4.14053
File Name: Sect B-B.gsz
Name: 4A4 - Sliding Block Failure - Subgrade
Description: Sliding Failure of Subgrade above Bedrock
Non-Optimized to force sliding
Method: Morgenstern-Price
Slip Surface Option: Fully-Specified
Color Name Piezometric
Line
Unit
Weight
(pcf)
Cohesion'
(psf)
Phi'
(°)
Bedrock 1
C&D Waste 1 75 200 30
Partially Weathered
Rock (PWR) (Effective)
1 125 500 35
Residual Soils - Sand
and Silts (Effective)
1 125 0 31
Structurall Fill
(Effective)
1 120 150 29.5

APPENDIX C
VENEER SLIDING STABILITY ANALYSIS
FINAL COVER
August 31, 2017
Slope Seismic Conditions Factor
Length
Thickness Unit Wt.Cohesion Coefficient
Total
Weight
Normal
Force Adhesive
Total
Weight Cohesive a b c of
L h γ c WA NA Adhesion Force, Ca WP Force, C Safety
degrees radians Feet Feet pcf degrees radians psf lb/ft lb/ft degrees radians psf lb/ft lb/ft lb/ft
Total Slope 18.44 0.322 676 3 120 29.5 0.515 150 0 239,770.3 227,459.4 27.5 0.480 0 99,977.4 1,799.6 1,422.6 22,758.0 -70,596.2 6,702.7 Static 3.00
Between Benches 18.44 0.322 210 3 120 29.5 0.515 150 0 72,010.3 68,313.0 27.5 0.480 0 30,077.4 1,799.6 1,422.6 6,834.9 -21,757.7 2,013.0 Static 3.09
Between Benches &
Tack-On Berms 18.44 0.322 98 3 120 29.5 0.515 150 0 31,690.3 30,063.2 27.5 0.480 0 13,277.4 1,799.6 1,422.6 3,007.9 -10,019.7 885.9 Static 3.24
Reference: Koerner & Soong. Analysis and Design of Veneer Cover Soils; Geosynthetics International, 2005, 12, No. 1, pp 28-49.
Calculated by:Larry Simonson, P.E.8/31/2017
Checked by: Gary Weekley, P.E. 9/1/2017Reviewed by: Jeff Helvey, P.E. 9/6/2017
VENEER SLIDING STABILITY - FINITE SLOPE LENGTH
BLE PROJECT NO. J16-9378-06
PHASE 6 - C&D DHR
BUNCOMBE COUNTY LANDFILLBUNCOMBE COUNTY, NORTH CAROLINA
ϕ
Cover Soil
Interface FrictionScenario:
Calculated Parameters
Passive Wedge Quadratic Equation ParametersSlope Angle
β
Active Wedge
δ
Friction Angle

APPENDIX D
SUBGRADE SETTLEMENT ANALYSIS
• GROUNDWATER SEPARATION
• BEDROCK SEPARATION

SOIL BORINGS
TOPSOIL
Dense, yellowish-brown and
black, dry, silty, fine to coarse
SAND with pebble sized gravel -
(residuum)
PARTIALLY WEATHERED ROCK
which sampled as very dense,
gray and white, dry, silty, clayey,
fine to medium SAND
PARTIALLY WEATHERED ROCK
which sampled as very dense,
gray and white, moist, silty,
clayey, fine to medium SAND
Auger refusal at 21.0 feet
Drill cuttings which sampled as
feldspar, quartz, hornblende,
GNEISS
11
14
20
36
50/4"
50/2"
50/3"
50/5"
50/1"
SURFACE COMPLETION
3.47-foot stick-up
Top of PVC casing elev. = 2,069.69
feet
Ground surface elev. = 2066.22 feet
Northing = 737,785.684'
Easting = 919,292.441'
Bentonite seal, 0 to 50.4 feet
DESCRIPTION
LOCATION:
DRILLER:
DRILLING METHOD:
2065
2060
2055
2050
2045
2040
2035
2030
CAVING>
GROUNDWATER MONITORING WELL NO. B-801
Sheet 1 of 2
2-24-17
Buncombe County, North Carolina
Landprobe, R. Banks
5
10
15
20
25
30
35
PROJECT:
CME 750; 8-1/4 inch OD hollow stem auger and 5-inch OD air drill
J17-9378-06
AFTER 24 HOURS:36.8
GROUNDWATER MONITORING WELL NO. B-801
START: 2-23-17
2066.22ELEVATION:
I. IrizarryLOGGED BY:
Buncombe County Landfill
Environmental Infrastructure Consulting, PLLC
DEPTH TO - WATER> INITIAL:
CLIENT:
44.0
PROJECT NO.:
END:
ELEVATION/
DEPTH (FT)GEOT_WELL 9378-06.GPJ 9/6/17SOIL
TYPE
SAMPLES102 5 20 30 40 50 70 90
STANDARD PENETRATION RESULTS
BLOWS/FOOT
MONITOR WELL INSTALLATION
DETAILS
50/4"
50/2"
50/3"
50/5"
50/1"
Drill cuttings which sampled as
feldspar, quartz, hornblende,
GNEISS
Drill cuttings which sampled as
feldspar, quartz, hornblende,
GNEISS
Fracture at 50.5 feet
Fracture at 55 feet
Fracture at 56 feet
Drill cuttings which sampled as
feldspar, quartz, hornblende,
GNEISS
Water bearing fracture at 65 feet
Boring terminated at 69.0 feet.
Groundwater encountered at
44.0 feet at time of drilling and at
36.8 feet after 24 hours
Bentonite seal, 0 to 50.4 feet
Filter pack, sand 50.4 to 69.0 feet
2-inch diameter, 0.010-inch slotted
Schedule 40 PVC well screen, 53.8
to 68.8 feet
Pipe cap
Total well depth, 69.0 feet
DESCRIPTION
LOCATION:
DRILLER:
DRILLING METHOD:
2025
2020
2015
2010
2005
2000
1995
1990
CAVING>
GROUNDWATER MONITORING WELL NO. B-801
Sheet 2 of 2
2-24-17
Buncombe County, North Carolina
Landprobe, R. Banks
45
50
55
60
65
70
75
PROJECT:
CME 750; 8-1/4 inch OD hollow stem auger and 5-inch OD air drill
J17-9378-06
AFTER 24 HOURS:36.8
GROUNDWATER MONITORING WELL NO. B-801
START: 2-23-17
2066.22ELEVATION:
I. IrizarryLOGGED BY:
Buncombe County Landfill
Environmental Infrastructure Consulting, PLLC
DEPTH TO - WATER> INITIAL:
CLIENT:
44.0
PROJECT NO.:
END:
ELEVATION/
DEPTH (FT)GEOT_WELL 9378-06.GPJ 9/6/17SOIL
TYPE
SAMPLES102 5 20 30 40 50 70 90
STANDARD PENETRATION RESULTS
BLOWS/FOOT
MONITOR WELL INSTALLATION
DETAILS
Very stiff, grayish-brown, dry,
silty, fine to medium SAND -
(residuum)
PARTIALLY WEATHERED ROCK
which sampled as very dense,
gray and brown, dry, micaceous,
silty, fine to coarse SAND with
gravel
Very dense, white and gray, dry,
silty, fine to medium SAND
PARTIALLY WEATHERED ROCK
which sampled as very dense,
white and gray, dry, silty, fine to
medium SAND
Auger refusal at 20.0 feet
BEDROCK which sampled as
feldspar, quartz, hornblende,
GNEISS with well developed
foliation
R-1 recovery = 62%, RQD = 50%
R-2 recovery = 90%, RQD = 52%
R-3 recovery = 72%, RQD = 54%
R-4 recovery = 89%, RQD = 81%
R-5 recovery = 100%, RQD = 64%
8
13
14
36
50/2"
50/4"
50/3"
11
33
47
50/3"
R-1
R-2
R-3
R-4
R-5
SURFACE COMPLETION
2.51-foot stick-up
Top of PVC casing elev. = 2,078.31
feet
Ground surface elev. = 2075.8 feet
Northing = 737,700.282'
Easting = 918,923.017'
Bentonite seal, 0 to 32.03 feet
Filter pack, sand 32.03 to 52.0 feet
DESCRIPTION
LOCATION:
DRILLER:
DRILLING METHOD:
2075
2070
2065
2060
2055
2050
2045
2040
CAVING>
GROUNDWATER MONITORING WELL NO. B-802
Sheet 1 of 2
2-24-17
Buncombe County, North Carolina
Landprobe, R. Banks
5
10
15
20
25
30
35
PROJECT:
CME 750; 8-1/4 inch OD hollow stem auger and HQ rock coring
J17-9378-06
AFTER 24 HOURS:43.82
GROUNDWATER MONITORING WELL NO. B-802
START: 2-23-17
2075.8ELEVATION:
I. IrizarryLOGGED BY:
Buncombe County Landfill
Environmental Infrastructure Consulting, PLLC
DEPTH TO - WATER> INITIAL:
CLIENT:
42.75
PROJECT NO.:
END:
ELEVATION/
DEPTH (FT)GEOT_WELL 9378-06.GPJ 9/6/17SOIL
TYPE
SAMPLES102 5 20 30 40 50 70 90
STANDARD PENETRATION RESULTS
BLOWS/FOOT
MONITOR WELL INSTALLATION
DETAILS
50/2"
50/4"
50/3"
50/3"
BEDROCK which sampled as
feldspar, quartz, hornblende,
GNEISS with well developed
foliation
R-6 recovery = 92%, RQD = 90%
R-7 recovery = 100%, RQD = 91%
Boring terminated at 52.0 feet.
Groundwater encountered at
42.75 feet at time of drilling and
at 43.82 feet after 24 hours.
R-6
R-7
2-inch diameter, 0.010-inch slotted
Schedule 40 PVC well screen, 34.3
to 49.3 feet
Pipe cap
Total well depth, 49.50 feet
DESCRIPTION
LOCATION:
DRILLER:
DRILLING METHOD:
2035
2030
2025
2020
2015
2010
2005
2000
CAVING>
GROUNDWATER MONITORING WELL NO. B-802
Sheet 2 of 2
2-24-17
Buncombe County, North Carolina
Landprobe, R. Banks
45
50
55
60
65
70
75
PROJECT:
CME 750; 8-1/4 inch OD hollow stem auger and HQ rock coring
J17-9378-06
AFTER 24 HOURS:43.82
GROUNDWATER MONITORING WELL NO. B-802
START: 2-23-17
2075.8ELEVATION:
I. IrizarryLOGGED BY:
Buncombe County Landfill
Environmental Infrastructure Consulting, PLLC
DEPTH TO - WATER> INITIAL:
CLIENT:
42.75
PROJECT NO.:
END:
ELEVATION/
DEPTH (FT)GEOT_WELL 9378-06.GPJ 9/6/17SOIL
TYPE
SAMPLES102 5 20 30 40 50 70 90
STANDARD PENETRATION RESULTS
BLOWS/FOOT
MONITOR WELL INSTALLATION
DETAILS
Hard, grayish-brown, dry to
slightly moist, fine to medium
sandy CLAY - (residuum)
Very hard, grayish-brown, dry to
slightly moist, fine to medium
sandy CLAY
PARTIALLY WEATHERED ROCK
which sampled as very hard,
gray, dry, micaceous, fine to
medium sandy SILT
Auger refusal at 26 feet
Drill cuttings which sampled as
feldspar, quartz, hornblende,
GNEISS
8
13
24
16
41
44
18
50/2"
50/1"
50/2"
50/1"
50/2"
SURFACE COMPLETION
3.59-foot stick-up
Top of PVC casing elev. = 2,044.71
feet
Ground surface elev. = 2,041.12
feet
Northing = 737,960.774'
Easting = 918,724.766'
Bentonite seal, 0 to 66.0 feet
DESCRIPTION
LOCATION:
DRILLER:
DRILLING METHOD:
2040
2035
2030
2025
2020
2015
2010
2005
CAVING>
GROUNDWATER MONITORING WELL NO. B-803
Sheet 1 of 3
2-10-17
Buncombe County, North Carolina
Landprobe, R. Banks
5
10
15
20
25
30
35
PROJECT:
CME 750; 8-1/4 inch OD hollow stem auger and 5-inch OD air drill
J17-9378-06
AFTER 24 HOURS:59.44
GROUNDWATER MONITORING WELL NO. B-803
START: 2-7-17
2041.12ELEVATION:
I. IrizarryLOGGED BY:
Buncombe County Landfill
Environmental Infrastructure Consulting, PLLC
DEPTH TO - WATER> INITIAL:
CLIENT:
59.94
PROJECT NO.:
END:
ELEVATION/
DEPTH (FT)GEOT_WELL 9378-06.GPJ 9/6/17SOIL
TYPE
SAMPLES102 5 20 30 40 50 70 90
STANDARD PENETRATION RESULTS
BLOWS/FOOT
MONITOR WELL INSTALLATION
DETAILS
50/2"
50/1"
50/2"
50/1"
50/2"
Drill cuttings which sampled as
feldspar, quartz, hornblende,
GNEISS
Drill cuttings which sampled as
feldspar, quartz, hornblende,
GNEISS
Fracture from 63 to 65 feet
Bentonite seal, 0 to 66.0 feet
Filter pack, sand 66.0 to 83.0 feet
2-inch diameter, 0.010-inch slotted
Schedule 40 PVC well screen, 67.8
to 82.8 feet
DESCRIPTION
LOCATION:
DRILLER:
DRILLING METHOD:
2000
1995
1990
1985
1980
1975
1970
1965
CAVING>
GROUNDWATER MONITORING WELL NO. B-803
Sheet 2 of 3
2-10-17
Buncombe County, North Carolina
Landprobe, R. Banks
45
50
55
60
65
70
75
PROJECT:
CME 750; 8-1/4 inch OD hollow stem auger and 5-inch OD air drill
J17-9378-06
AFTER 24 HOURS:59.44
GROUNDWATER MONITORING WELL NO. B-803
START: 2-7-17
2041.12ELEVATION:
I. IrizarryLOGGED BY:
Buncombe County Landfill
Environmental Infrastructure Consulting, PLLC
DEPTH TO - WATER> INITIAL:
CLIENT:
59.94
PROJECT NO.:
END:
ELEVATION/
DEPTH (FT)GEOT_WELL 9378-06.GPJ 9/6/17SOIL
TYPE
SAMPLES102 5 20 30 40 50 70 90
STANDARD PENETRATION RESULTS
BLOWS/FOOT
MONITOR WELL INSTALLATION
DETAILS
Drill cuttings which sampled as
feldspar, quartz, hornblende,
GNEISS
Boring terminated at 83.0 feet.
Groundwater encountered at
59.94 feet at time of drilling and
at 59.44 feet after 24 hours.
Pipe cap
Total well depth, 83.0 feet
DESCRIPTION
LOCATION:
DRILLER:
DRILLING METHOD:
1960
1955
1950
1945
1940
1935
1930
1925
CAVING>
GROUNDWATER MONITORING WELL NO. B-803
Sheet 3 of 3
2-10-17
Buncombe County, North Carolina
Landprobe, R. Banks
85
90
95
100
105
110
115
PROJECT:
CME 750; 8-1/4 inch OD hollow stem auger and 5-inch OD air drill
J17-9378-06
AFTER 24 HOURS:59.44
GROUNDWATER MONITORING WELL NO. B-803
START: 2-7-17
2041.12ELEVATION:
I. IrizarryLOGGED BY:
Buncombe County Landfill
Environmental Infrastructure Consulting, PLLC
DEPTH TO - WATER> INITIAL:
CLIENT:
59.94
PROJECT NO.:
END:
ELEVATION/
DEPTH (FT)GEOT_WELL 9378-06.GPJ 9/6/17SOIL
TYPE
SAMPLES102 5 20 30 40 50 70 90
STANDARD PENETRATION RESULTS
BLOWS/FOOT
MONITOR WELL INSTALLATION
DETAILS
Soft, grayish-brown, moist,
slightly micaceous, silty, fine to
medium SAND - (residuum)
Stiff, brown, moist, slightly
micaceous, fine to medium
sandy SILT
Loose, brown to gray, moist,
silty, medium to coarse SAND
with gravel
PARTIALLY WEATHERED ROCK
which sampled as very dense,
gray and brownish-gray,
micaceous, fine to medium
SAND
Auger refusal at 17.0 feet
Drill cuttings which sampled as
feldspar, quartz, hornblende,
GNEISS
Boring terminated at 31.0 feet.
Groundwater encountered at 7.0
feet at time of drilling and at 8.0
feet after 24 hours
2
2
2
3
6
7
5
5
5
5
15
48
50/4"
SURFACE COMPLETION
3.5-foot stick-up
Top of PVC casing elev. = 1,990.95
feet
Ground surface elev. = 1,987.45
feet
Northing = 737,997.784'
Easting = 918,926.868'
Bentonite seal, 0 to 18.7 feet
Filter pack, sand 18.7 to 30.45 feet
2-inch diameter, 0.010-inch slotted
Schedule 40 PVC well screen, 20.8
to 30.8 feet
Pipe cap
Total well depth, 31.0 feet
DESCRIPTION
LOCATION:
DRILLER:
DRILLING METHOD:
1985
1980
1975
1970
1965
1960
1955
1950
CAVING>
GROUNDWATER MONITORING WELL NO. B-804
Sheet 1 of 1
2-28-17
Buncombe County, North Carolina
Landprobe, R. Banks
5
10
15
20
25
30
35
PROJECT:
CME 750; 8-1/4 inch OD hollow stem auger and 5-inch OD air drill
J17-9378-06
AFTER 24 HOURS:8.0
GROUNDWATER MONITORING WELL NO. B-804
START: 2-27-17
1987.45ELEVATION:
I. IrizarryLOGGED BY:
Buncombe County Landfill
Environmental Infrastructure Consulting, PLLC
DEPTH TO - WATER> INITIAL:
CLIENT:
7.0
PROJECT NO.:
END:
ELEVATION/
DEPTH (FT)GEOT_WELL 9378-06.GPJ 9/6/17SOIL
TYPE
SAMPLES102 5 20 30 40 50 70 90
STANDARD PENETRATION RESULTS
BLOWS/FOOT
MONITOR WELL INSTALLATION
DETAILS
50/4"
Loose, brown, dry, slightly
micaceous, silty, fine to medium
SAND - (residuum)
PARTIALLY WEATHERED ROCK
which sampled as very dense,
dry to slightly moist, micaceous,
silty, fine to medium SAND
Auger refusal at 18 feet
Drill cuttings which sampled as
feldspar, quartz, hornblende,
GNEISS
3
4
4
18
50/4"
13
50/4"
50/2"
50/3"
SURFACE COMPLETION
3.45-foot stick-up
Top of PVC casing elev. = 1,994.45
feet
Ground surface elev. = 1,991.00
feet
Northing = 738,196.779'
Easting = 918,671.910'
Bentonite seal, 0 to 66.3 feet
DESCRIPTION
LOCATION:
DRILLER:
DRILLING METHOD:
1990
1985
1980
1975
1970
1965
1960
1955
CAVING>
GROUNDWATER MONITORING WELL NO. B-805
Sheet 1 of 3
2-16-17
Buncombe County, North Carolina
Landprobe, R. Banks
5
10
15
20
25
30
35
PROJECT:
CME 750; 8-1/4 inch OD hollow stem auger and 5-inch OD air drill
J17-9378-06
AFTER 24 HOURS:75.5
GROUNDWATER MONITORING WELL NO. B-805
START: 2-15-17
1991.00ELEVATION:
I. IrizarryLOGGED BY:
Buncombe County Landfill
Environmental Infrastructure Consulting, PLLC
DEPTH TO - WATER> INITIAL:
CLIENT:
77.0
PROJECT NO.:
END:
ELEVATION/
DEPTH (FT)GEOT_WELL 9378-06.GPJ 9/6/17SOIL
TYPE
SAMPLES102 5 20 30 40 50 70 90
STANDARD PENETRATION RESULTS
BLOWS/FOOT
MONITOR WELL INSTALLATION
DETAILS
50/4"
50/4"
50/2"
50/3"
Drill cuttings which sampled as
feldspar, quartz, hornblende,
GNEISS
Drill cuttings which sampled as
feldspar, quartz, hornblende,
GNEISS
Bentonite seal, 0 to 66.3 feet
Filter pack, sand 66.3 to 85.0 feet
2-inch diameter, 0.010-inch slotted
Schedule 40 PVC well screen,
69.25 to 84.25 feet
DESCRIPTION
LOCATION:
DRILLER:
DRILLING METHOD:
1950
1945
1940
1935
1930
1925
1920
1915
CAVING>
GROUNDWATER MONITORING WELL NO. B-805
Sheet 2 of 3
2-16-17
Buncombe County, North Carolina
Landprobe, R. Banks
45
50
55
60
65
70
75
PROJECT:
CME 750; 8-1/4 inch OD hollow stem auger and 5-inch OD air drill
J17-9378-06
AFTER 24 HOURS:75.5
GROUNDWATER MONITORING WELL NO. B-805
START: 2-15-17
1991.00ELEVATION:
I. IrizarryLOGGED BY:
Buncombe County Landfill
Environmental Infrastructure Consulting, PLLC
DEPTH TO - WATER> INITIAL:
CLIENT:
77.0
PROJECT NO.:
END:
ELEVATION/
DEPTH (FT)GEOT_WELL 9378-06.GPJ 9/6/17SOIL
TYPE
SAMPLES102 5 20 30 40 50 70 90
STANDARD PENETRATION RESULTS
BLOWS/FOOT
MONITOR WELL INSTALLATION
DETAILS
Drill cuttings which sampled as
feldspar, quartz, hornblende,
GNEISS
Boring terminated at 85.0 feet.
Groundwater encountered at
77.0 feet at time of drilling and at
75.5 feet after 24 hours.
Pipe cap
Total well depth, 84.5 feet
DESCRIPTION
LOCATION:
DRILLER:
DRILLING METHOD:
1910
1905
1900
1895
1890
1885
1880
1875
CAVING>
GROUNDWATER MONITORING WELL NO. B-805
Sheet 3 of 3
2-16-17
Buncombe County, North Carolina
Landprobe, R. Banks
85
90
95
100
105
110
115
PROJECT:
CME 750; 8-1/4 inch OD hollow stem auger and 5-inch OD air drill
J17-9378-06
AFTER 24 HOURS:75.5
GROUNDWATER MONITORING WELL NO. B-805
START: 2-15-17
1991.00ELEVATION:
I. IrizarryLOGGED BY:
Buncombe County Landfill
Environmental Infrastructure Consulting, PLLC
DEPTH TO - WATER> INITIAL:
CLIENT:
77.0
PROJECT NO.:
END:
ELEVATION/
DEPTH (FT)GEOT_WELL 9378-06.GPJ 9/6/17SOIL
TYPE
SAMPLES102 5 20 30 40 50 70 90
STANDARD PENETRATION RESULTS
BLOWS/FOOT
MONITOR WELL INSTALLATION
DETAILS
Firm, brown, dry, slightly
micaceous, silty, fine to medium
SAND - (residuum)
Dense, brown, dry, micaceous,
silty, fine to medium SAND
PARTIALLY WEATHERED ROCK
which sampled as very dense,
brownish-gray and brown, dry,
very micaceous, silty, fine to
medium SAND
Auger refusal at 12.0 feet
Drill cuttings which sampled as
feldspar, quartz, hornblende,
GNEISS
Fracture/soil seam from 37 to 38
feet
6
7
9
7
17
19
21
50/4"
50/1"
SURFACE COMPLETION
3.38-foot stick-up
Top of PVC casing elev. = 2,026.22
feet
Ground surface elev. = 2,022.84
feet
Northing = 738,294.333'
Easting = 919,007.308'
Bentonite seal, 0 to 25.6 feet
Filter pack, sand 25.6 to 53.5 feet
DESCRIPTION
LOCATION:
DRILLER:
DRILLING METHOD:
2020
2015
2010
2005
2000
1995
1990
1985
CAVING>
GROUNDWATER MONITORING WELL NO. B-806
Sheet 1 of 2
3-2-17
Buncombe County, North Carolina
Landprobe, R. Banks
5
10
15
20
25
30
35
PROJECT:
CME 750; 8-1/4 inch OD hollow stem auger and 5-inch OD air drill
J17-9378-06
AFTER 24 HOURS:44.07
GROUNDWATER MONITORING WELL NO. B-806
START: 3-1-17
2022.84ELEVATION:
I. IrizarryLOGGED BY:
Buncombe County Landfill
Environmental Infrastructure Consulting, PLLC
DEPTH TO - WATER> INITIAL:
CLIENT:
44.0
PROJECT NO.:
END:
ELEVATION/
DEPTH (FT)GEOT_WELL 9378-06.GPJ 9/6/17SOIL
TYPE
SAMPLES102 5 20 30 40 50 70 90
STANDARD PENETRATION RESULTS
BLOWS/FOOT
MONITOR WELL INSTALLATION
DETAILS
50/4"
50/1"
Drill cuttings which sampled as
feldspar, quartz, hornblende,
GNEISS
Drill cuttings which sampled as
feldspar, quartz, hornblende,
GNEISS
Soil seam from 46 to 47 feet
Boring terminated at 53.5 feet.
Groundwater encountered at
44.0 feet at time of drilling and at
44.02 feet after 24 hours.
2-inch diameter, 0.010-inch slotted
Schedule 40 PVC well screen, 38.3
to 53.3 feet
Pipe cap
Total well depth, 53.50 feet
DESCRIPTION
LOCATION:
DRILLER:
DRILLING METHOD:
1980
1975
1970
1965
1960
1955
1950
1945
CAVING>
GROUNDWATER MONITORING WELL NO. B-806
Sheet 2 of 2
3-2-17
Buncombe County, North Carolina
Landprobe, R. Banks
45
50
55
60
65
70
75
PROJECT:
CME 750; 8-1/4 inch OD hollow stem auger and 5-inch OD air drill
J17-9378-06
AFTER 24 HOURS:44.07
GROUNDWATER MONITORING WELL NO. B-806
START: 3-1-17
2022.84ELEVATION:
I. IrizarryLOGGED BY:
Buncombe County Landfill
Environmental Infrastructure Consulting, PLLC
DEPTH TO - WATER> INITIAL:
CLIENT:
44.0
PROJECT NO.:
END:
ELEVATION/
DEPTH (FT)GEOT_WELL 9378-06.GPJ 9/6/17SOIL
TYPE
SAMPLES102 5 20 30 40 50 70 90
STANDARD PENETRATION RESULTS
BLOWS/FOOT
MONITOR WELL INSTALLATION
DETAILS
PARTIALLY WEATHERED ROCK
which sampled as light brown to
brown, slightly micaceous, dry,
silty, fine to medium SAND -
(residuum)
Auger refusal at 15.0 feet
BEDROCK which sampled as
feldspar, quartz, hornblende,
GNEISS with well developed
folations and close mechanical
breaks
R-1 recovery = 100%, RQD = 54%
R-2 recovery = 43.5%, RQD =
42%
Fracture at 17 feet
Fracture at 18 feet
Fracture at 19.5 feet
R-3 recovery = 12%, RQD = 0%
R-4 recovery = 80%, RQD = 62%
Fracture at 21.5 feet
Fracture at 23.3 feet
R-5 recovery = 56%, RQD = 28%
Fracture at 27.5 feet
Fracture at 28.5 feet
R-6 recovery = 90%, RQD = 87%
Fracture at 31.5 feet
Fracture at 33.5 feet
R-7 recovery = 87%, RQD = 84%
Fracture at 36.5 feet
3
50
50/3"
37
39
50/4"
24
50/5"
50/5"
R-1
R-2
R-3
R-4
R-5
R-6
R-7
SURFACE COMPLETION
3.85-foot stick-up
Top of PVC casing elev. = 1,987.80
feet
Ground surface elev. = 1,983.95
feet
Northing = 738,393.993'
Easting = 918,877.507'
Bentonite seal, 0 to 32.7 feet
Filter pack, sand 32.7 to 50.0 feet
DESCRIPTION
LOCATION:
DRILLER:
DRILLING METHOD:
1980
1975
1970
1965
1960
1955
1950
1945
CAVING>
GROUNDWATER MONITORING WELL NO. B-807
Sheet 1 of 2
3-6-17
Buncombe County, North Carolina
Landprobe, R. Banks
5
10
15
20
25
30
35
PROJECT:
CME 750; 8-1/4 inch OD hollow stem auger and HQ rock coring
J17-9378-06
AFTER 24 HOURS:36.18
GROUNDWATER MONITORING WELL NO. B-807
START: 3-5-17
1983.95ELEVATION:
I. IrizarryLOGGED BY:
Buncombe County Landfill
Environmental Infrastructure Consulting, PLLC
DEPTH TO - WATER> INITIAL:
CLIENT:
36.20
PROJECT NO.:
END:
ELEVATION/
DEPTH (FT)GEOT_WELL 9378-06.GPJ 9/6/17SOIL
TYPE
SAMPLES102 5 20 30 40 50 70 90
STANDARD PENETRATION RESULTS
BLOWS/FOOT
MONITOR WELL INSTALLATION
DETAILS
50/3"
50/4"
50/5"
50/5"
R-8 recovery = 100%, RQD = 85%
BEDROCK which sampled as
feldspar, quartz, hornblende,
GNEISS with well developed
folations and close mechanical
breaks
Fracture at 41.5 feet
Fracture at 43.5 feet
R-9 recovery = 97%, RQD = 88%
Fracture at 46.5 feet
Boring terminated at 50.0 feet.
Groundwater encountered at
36.20 feet at time of drilling and
at 36.18 feet after 24 hours.
R-8
R-9
2-inch diameter, 0.010-inch slotted
Schedule 40 PVC well screen,
33.82 to 48.82 feet
Pipe cap
Total well depth, 49.20 feet
DESCRIPTION
LOCATION:
DRILLER:
DRILLING METHOD:
1940
1935
1930
1925
1920
1915
1910
1905
CAVING>
GROUNDWATER MONITORING WELL NO. B-807
Sheet 2 of 2
3-6-17
Buncombe County, North Carolina
Landprobe, R. Banks
45
50
55
60
65
70
75
PROJECT:
CME 750; 8-1/4 inch OD hollow stem auger and HQ rock coring
J17-9378-06
AFTER 24 HOURS:36.18
GROUNDWATER MONITORING WELL NO. B-807
START: 3-5-17
1983.95ELEVATION:
I. IrizarryLOGGED BY:
Buncombe County Landfill
Environmental Infrastructure Consulting, PLLC
DEPTH TO - WATER> INITIAL:
CLIENT:
36.20
PROJECT NO.:
END:
ELEVATION/
DEPTH (FT)GEOT_WELL 9378-06.GPJ 9/6/17SOIL
TYPE
SAMPLES102 5 20 30 40 50 70 90
STANDARD PENETRATION RESULTS
BLOWS/FOOT
MONITOR WELL INSTALLATION
DETAILS
Loose, brown, dry, micaceous,
silty, fine to medium SAND -
(residuum)
Firm, brown, dry, slightly
micaceous, silty, fine to medium
SAND
Very firm, grayish-brown and
brown, dry to moist, slightly
micaceous, silty, fine to medium
SAND
Auger refusal at 13.0 feet
Drill cuttings which sampled as
feldspar, quartz, hornblende,
GNEISS
Boring terminated at 15.47 feet.
Groundwater encountered at
5.99 feet at time of drilling and at
6.00 feet after 24 hours.
2
2
4
3
4
10
3
8
14
4
7
20
Bentonite seal, 0 to 3.0 feet
Filter pack, sand 3.0 to 15.47 feet
2-inch diameter, 0.010-inch slotted
Schedule 40 PVC well screen, 5.2
to 15.2 feet
Pipe cap
Total well depth, 15.47 feet
SURFACE COMPLETION
3.83-foot stick-up
Top of PVC casing elev. = 1,885.79
feet
Ground surface elev. = 1,881.96
feet
Northing = 738,523.785'
Easting = 918,658.117'
DESCRIPTION
LOCATION:
DRILLER:
DRILLING METHOD:
1880
1875
1870
1865
1860
1855
1850
1845
CAVING>
GROUNDWATER MONITORING WELL NO. B-808S
Sheet 1 of 1
3-10-17
Buncombe County, North Carolina
Landprobe, R. Banks
5
10
15
20
25
30
35
PROJECT:
CME 750; 8-1/4 inch OD hollow stem auger and 5-inch OD air drill
J17-9378-06
AFTER 24 HOURS:6.00
GROUNDWATER MONITORING WELL NO. B-808S
START: 3-9-17
1881.96ELEVATION:
I. IrizarryLOGGED BY:
Buncombe County Landfill
Environmental Infrastructure Consulting, PLLC
DEPTH TO - WATER> INITIAL:
CLIENT:
5.99
PROJECT NO.:
END:
ELEVATION/
DEPTH (FT)GEOT_WELL 9378-06.GPJ 9/6/17SOIL
TYPE
SAMPLES102 5 20 30 40 50 70 90
STANDARD PENETRATION RESULTS
BLOWS/FOOT
MONITOR WELL INSTALLATION
DETAILS
Loose, brown, dry, micaceous,
silty, fine to medium SAND -
(residuum)
Firm, brown, dry, slightly
micaceous, silty, fine to medium
SAND
Very firm, grayish-brown and
brown, dry to moist, slightly
micaceous, silty, fine to medium
SAND
Auger refusal at 13.0 feet
Drill cuttings which sampled as
feldspar, quartz, hornblende,
GNEISS
Fracture at 18 feet
Boring terminated at 33.0 feet.
Groundwater encountered at
7.95 feet at time of drilling and at
7.95 feet after 24 hours.
SURFACE COMPLETION
3.43-foot stick-up
Top of PVC casing elev. = 1,885.62
feet
Ground surface elev. = 1,882.19
feet
Northing = 738,519.801'
Easting = 918,657.775'
Bentonite seal, 0 to 25.5 feet
Filter pack, sand 25.5 to 33.0 feet
2-inch diameter, 0.010-inch slotted
Schedule 40 PVC well screen, 26.6
to 31.6 feet
Pipe cap
Total well depth, 31.80 feet
DESCRIPTION
LOCATION:
DRILLER:
DRILLING METHOD:
1880
1875
1870
1865
1860
1855
1850
1845
CAVING>
GROUNDWATER MONITORING WELL NO. B-808D
Sheet 1 of 1
3-9-17
Buncombe County, North Carolina
Landprobe, R. Banks
5
10
15
20
25
30
35
PROJECT:
CME 750; 8-1/4 inch OD hollow stem auger and 5-inch OD air drill
J17-9378-06
AFTER 24 HOURS:7.95
GROUNDWATER MONITORING WELL NO. B-808D
START: 3-9-17
1882.19ELEVATION:
I. IrizarryLOGGED BY:
Buncombe County Landfill
Environmental Infrastructure Consulting, PLLC
DEPTH TO - WATER> INITIAL:
CLIENT:
7.95
PROJECT NO.:
END:
ELEVATION/
DEPTH (FT)GEOT_WELL 9378-06.GPJ 9/6/17SOIL
TYPE
SAMPLES102 5 20 30 40 50 70 90
STANDARD PENETRATION RESULTS
BLOWS/FOOT
MONITOR WELL INSTALLATION
DETAILS

SETTLEMENT ANALYSIS
BLE
Location Boring Pre-Subgrade Cut (-)Elevation
Number ConstructionElevation or C&D Cap Finished
Ground Fill (+)Waste Cap
Elevation Depth
at Point
Feet Feet Feet Feet Feet Feet
B-801 2066.3 2058.8 -7.50 66.31 3.00 2128.1
B-802 2075.2 2059.8 -15.37 38.49 3.00 2101.3
B-803 2041.3 2020.0 -21.27 3.49 3.00 2026.5
B-804 1986.9 1992.9 6.01 64.22 3.00 2060.1
Max Waste
& Fill B-804 2014.8 2023.4 8.59 112.85 3.00 2139.2
B-805 1987.6 1976.0 -11.58 -1.96 3.00 1977.0
B-806 2020.6 2010.9 -9.72 0.63 3.00 2014.5
B-622 2003.0 2014.4 11.44 96.82 3.00 2114.2
B-624D 1976.7 1974.6 -2.03 29.59 3.00 2007.2
B-625 2051.6 2049.0 -2.63 41.71 3.00 2093.7
prepared by:Gary L. Weekley, P.E.C&D Waste 75 pcf
checked by:Larry A. Simonson, P.E.Structural Fill 120 pcf
Cap Soil 120 pcf
8,824
(1) References to Cell Floor Elevation, Locations shown on McGill Associates Figure C-101,
"CDLF Phase 6 Preliminary Site Layout."
(2) Net Surcharge = cap weight + weight of waste down to protective cover - net stress relief between
original ground and subgrade elevations.
7,621
2,336
-1,177
-759
Material Unit Weight
3,173
Subgrade and finished grade (cap) elevations from electronic drawing titled "Preliminary Phase 6 Base & Cap
Grades 6-26-17" by McGill Associates provided June 26, 2017.
Existing ground surface information obtained from electronic drawing titled "BCLF Phase 6 CD Basemap with March
2017 Topo provided by McGill Associates
psf
4,433
1,402
-1,931
5,177
BUNCOMBE COUNTY, NORTH CAROLINA
SURCHARGE DETERMINATION
SETTLEMENT CALCULATIONS
PHASE 6 C&D
BUNCOMBE COUNTY LANDFILL
Elevation
Subgrade
BLE Project No. J16-9378-06
September 2017
Net
Pressure(2)
at Waste
Layer Thickness
BLE
revised 9-5-17
Standard Layer Total Effective Surcharge Soil Layer
Penetration Thickness Soil Unit Soil Unit Pressure1 Modulus Settlement
Resistance Weight Weight
(N-Value)
bpf feet pcf pcf psf ksf inches
Settlement Point No.:B-801
2059 -2049 PWR silty clayey SAND 200 10 120 120 4,433 1,350 0.2
2049 -2045 V Hd PWR silty clyey SAND 600 4 120 120 4,433 2,790 0.0
Total Thickness of Compressible Material 14 Feet
TOTAL ESTIMATED SETTLEMENT (inches)0.2
TOTAL ESTIMATED SETTLEMENT (feet)0.02
Settlement Point No.:B-802
2060 -2059 Very Dense silty SAND 80 1 120 120 1,402 740 0.0
2059 -2056 PWR silty SAND 200 3 120 120 1,402 1,350 0.0
Total Thickness of Compressible Material 4 Feet
TOTAL ESTIMATED SETTLEMENT (inches)0.0
TOTAL ESTIMATED SETTLEMENT (feet)0.00
1 Surcharge pressure assumes weight of C&D Waste of 75 pcf
Reference McGill Associates Figure C-101 for settlement Point Locations
SETTLEMENT CALCULATIONS - PHASE 6 C&D
BUNCOMBE COUNTY LANDFILL
BUNCOMBE COUNTY, NORTH CAROLINA
Bunnell-Lammons Engineering, Inc. Project No. J16-9378-06
Soil Type
Subsurface Layer
Elevation
feet
BLE
revised 9-5-17
Standard Layer Total Effective Surcharge Soil Layer
Penetration Thickness Soil Unit Soil Unit Pressure1 Modulus Settlement
Resistance Weight Weight
(N-Value)
bpf feet pcf pcf psf ksf inches
Settlement Point No.:B-804 At Maximum Waste & Fill
2023 -2015 Fill NA 8 110 110 8,824 240 2.1
2015 -2012 Very loose silty SAND 4 3 120 120 8,824 100 1.9
2012 -2007 Stiff sandy SILT 11 5 120 120 8,824 200 1.6
2007 -2003 Very Dense SAND 63 4 120 58 8,824 630 0.4
2003 -1998 PWR SAND 150 5 140 78 8,824 1,120 0.3
Total Thickness of Compressible Material 25 Feet
TOTAL ESTIMATED SETTLEMENT (inches)6.3
TOTAL ESTIMATED SETTLEMENT (feet)0.53
Settlement Point No.:B-804
1993 -1987 Fill NA 6 110 110 5,177 240 0.9
1987 -1984 Very loose silty SAND 4 3 120 120 5,177 100 1.1
1984 -1979 Stiff sandy SILT 11 5 120 120 5,177 200 0.9
1979 -1975 Very Dense SAND 63 4 120 58 5,177 630 0.2
1975 1970 PWR SAND 150 5 140 78 5,177 1,120 0.2
Total Thickness of Compressible Material 23 Feet
TOTAL ESTIMATED SETTLEMENT (inches)3.3
TOTAL ESTIMATED SETTLEMENT (feet)0.28
1 Surcharge pressure assumes weight of C&D Waste of 75 pcf
Reference McGill Associates Figure C-101 for settlement Point Locations
SETTLEMENT CALCULATIONS - PHASE 6 C&D
Subsurface Layer
Soil Type
Elevation
feet
BUNCOMBE COUNTY, NORTH CAROLINA
BUNCOMBE COUNTY LANDFILL
Bunnell-Lammons Engineering, Inc. Project No. J16-9378-06
BLE
revised 9-5-17
Standard Layer Total Effective Surcharge Soil Layer
Penetration Thickness Soil Unit Soil Unit Pressure1 Modulus Settlement
Resistance Weight Weight
(N-Value)
bpf feet pcf pcf psf ksf inches
Settlement Point No.:B-622
2014.4 -2003 Fill NA 11.4 110 110 7,621 240 2.6
2003.0 -1999 Loose silty SAND 6 4.0 110 110 7,621 130 1.7
1999.0 -1994 Firm silty SAND 18 5.0 120 58 7,621 280 1.0
1994.0 -1991 PWR silty SAND 120 3.0 140 78 7,621 970 0.2
Total Thickness of Compressible Material 23.4 Feet
TOTAL ESTIMATED SETTLEMENT (inches)5.5
TOTAL ESTIMATED SETTLEMENT (feet)0.46
Settlement Point No.:B-624D
1975 -1972 Loose silty SAND 6 3 110 110 2,336 130 0.4
1972 -1967 PWR silty SAND 150 5 140 140 2,336 1,120 0.1
Total Thickness of Compressible Material 8 Feet
TOTAL ESTIMATED SETTLEMENT (inches)0.5
TOTAL ESTIMATED SETTLEMENT (feet)0.04
1 Surcharge pressure assumes weight of C&D Waste of 75 pcf
Reference McGill Associates Figure C-101 for settlement Point Locations
BUNCOMBE COUNTY LANDFILL
BUNCOMBE COUNTY, NORTH CAROLINA
Bunnell-Lammons Engineering, Inc. Project No. J16-9378-06
SETTLEMENT CALCULATIONS - PHASE 6 C&D
Subsurface Layer
Soil Type
Elevation
feet
BLE
revised 9-5-17
Standard Layer Total Effective Surcharge Soil Layer
Penetration Thickness Soil Unit Soil Unit Pressure1 Modulus Settlement
Resistance Weight Weight
(N-Value)
bpf feet pcf pcf psf ksf inches
Settlement Point No.:B-625
2049 -2048 Very Firm SAND 20 1 3,173 300 0.1
2048 -2044 PWR SAND 150 4 3,173 1,120 0.1
Total Thickness of Compressible Material 5 Feet
TOTAL ESTIMATED SETTLEMENT (inches)0.2
TOTAL ESTIMATED SETTLEMENT (feet)0.02
Settlement Point No.:
Total Thickness of Compressible Material Feet
TOTAL ESTIMATED SETTLEMENT (inches)0.0
TOTAL ESTIMATED SETTLEMENT (feet)0.00
1 Surcharge pressure assumes weight of C&D Waste of 75 pcf
Reference McGill Associates Figure C-101 for settlement Point Locations
Subsurface Layer
Soil Type
Elevation
feet
SETTLEMENT CALCULATIONS - PHASE 6 C&D
BUNCOMBE COUNTY LANDFILL
BUNCOMBE COUNTY, NORTH CAROLINA
Bunnell-Lammons Engineering, Inc. Project No. J16-9378-06
BLE
Phase Settlement Estimated Subgrade Groundwater Groundwater
Number Point Settlement Elevation Elevation(2)Elevation
Reference(1)Separation
Feet Feet Feet Feet
6 B-801 0.02 2058.79 2031.52 27.25
6 B-802 0.00 2059.80 2031.90 27.90
6 B-804 0.28 1992.91 1981.60 11.04
6 B-804 (max. waste)0.53 2023.37 2008.44 14.40
6 B-622 0.46 2014.40 1998.9 15.05
6 B-624D 0.04 1974.62 1961.7 12.92
6 B-625 0.02 2049.00 2011.8 37.16
September 5, 2017
Note (2): Reference BLE Figure "Seasonal High Groundwater Elevation Contour Map: 2017 for
Groundwater Contours."
GROUNDWATER SEPARATION WITH SUBGRADE
POST-SETTLEMENT
PHASE 6 C&D
BUNCOMBE COUNTY, NORTH CAROLINA
BLE Project No. J16-9378-06
Note (1): Reference McGill Associates Figure C-101 for settlement Point Locations and Initial Cell Grades
BUNCOMBE COUNTY LANDFILL
BLE
Phase Settlement Estimated Subgrade Bedrock Bedrock
Number Point Settlement Elevation Elevation(2)Elevation
Reference(1)Separation
Feet Feet Feet Feet
6 B-801 0.02 2058.79 2045.20 13.57
6 B-802 0.00 2059.80 2055.80 4.00
6 B-804 0.28 1992.91 1970.50 22.14
6 B-804 (max. waste)0.53 2023.37 2014.40 8.44
6 B-622 0.46 2014.40 1991.10 22.84
6 B-624D 0.04 1974.62 1967.60 6.98
6 B-625 0.02 2049.00 2044.40 4.58
BUNCOMBE COUNTY LANDFILL
September 5, 2017
BLE Project No. J16-9378-06
Note (2): Reference BLE Figure "Top of Bedrock Elevation Contour Map."
BEDROCK SEPARATION WITH SUBGRADE
PHASE 6 C&D
BUNCOMBE COUNTY, NORTH CAROLINA
POST-SETTLEMENT
Note (1): Reference McGill Associates Figure C-101 for settlement Point Locations and Initial Cell Grades

APPENDIX E
• DRAINAGE LAYER ANALYSIS
• SELECTION OF NONWOVEN
GEOTEXTILE FOR DRAIN

BLEINC.

DRAINAGE LAYER ANALYSIS FOR EMBANKMENT UNDERDRAIN

PHASE 6 C&D EXPANSION AREA
BUNCOMBE COUNTY C&D LANDFILL
ALEXANDER, NORTH CAROLINA
BLE Project No. J16-9378-06

References: Giroud, JP, Zonrberg, JG., and Zhao, A. (2000), Hydraulic Design of Geosynthetic and
Granular Liquid Collection Layers

The planned underdrain below Phase 6 C&D subgrade and the proposed embankment will have a maximum
slope of 2.5 horizontal to 1 vertical (2.5H:1V). This analysis is based on the slope geometry depicted in the
design drawings prepared by McGill Associates dated June 2017.

The purpose of this analysis is to determine whether the proposed 2-feet x 2-feet stone underdrain will provide
a suitable hydraulic conductivity (kallow) to drain the expected groundwater below the proposed Phase 6 C&D
waste phase and north embankment. The suitability of the underdrain is expressed as a function of factor of
safety:

𝐹.𝑅.=𝑘𝑎𝑙𝑙𝑜𝑤
𝑘𝑜𝑑𝑜

Where: kallow = Hydraulic conductivity of the underdrain stone
kreq = Minimum required hydraulic conductivity to drain the expected groundwater flow

The allowable hydraulic conductivity of the stone can be calculated as:

𝑘𝑎𝑙𝑙𝑜𝑤=𝑘𝑙𝑑𝑎𝑜𝑢𝑜𝑑𝑑
𝑅𝐹𝑃𝐵∗𝑅𝐹𝐵𝐵∗𝑅𝐹𝐵𝐵

Where: kmeasured = Measured hydraulic conductivity of stone.
Assuming No. 57 stone, typically = 10 cm/s
RFPC = Reduction for particulate clogging = 1.2
RFCC = Reduction for chemical clogging = 1.2
RFBC = Reduction for biological clogging = 1.5

𝑘𝑎𝑙𝑙𝑜𝑤=10 𝑐𝑚𝑞⁄
1.2 ∗1.2 ∗1.5 ∗(1�ℎ𝑚
2.54𝑐𝑚)∗(1𝑓𝑞
12�ℎ𝑚)∗60𝑞
1𝑚�ℎ𝑚∗60𝑚�ℎ𝑚
1�𝑞∗24�𝑞
1𝑐𝑎𝑦

𝑘𝑎𝑙𝑙𝑜𝑤=13,123.4 𝑓𝑞/𝑐𝑎𝑦
BLEINC.

Underdrain Drainage Analysis BLE Project No. J16-9378-06
Buncombe County C&D Landfill
Alexander, North Carolina

Project Name: Buncombe County Landfill – Phase 6 C&D Expansion
Project No.: J16-9378-06
Prepared By: Larry A. Simonson, P.E.
Reviewed By: Gary L. Weekley, P.E.
Reviewed By: Jeff C. Helvey, P.E.
2
The minimum required hydraulic conductivity can be determined by rearranging Darcy’s Law and determining
the fluid supply rate by calculating seepage from a flow net of the area of interest:

Darcy’s Law:
𝑞=𝑘�ℎ𝑎
Rearranged:
𝑘𝑜𝑑𝑜=𝑞
�ℎ𝑎

Where: q = fluid supply rate to the underdrain
i = Hydraulic gradient (change in elevation / length) = 0.16 below embankment
a = Cross section area of the underdrain: 2-ft x 2-ft = 4 ft2

The attached flow net calculates the expected fluid supply rate at the base of the Phase 6 north embankment
conservatively assuming Sediment Basin 13 is drained to the toe of the embankment at elevation 1886 feet
above MSL. For each the flow net, the fluid supply rate is calculated as the seepage at a particular point in the
net:

𝑞=𝑘∗𝐻∗𝑁𝑑
𝑁𝑜

Where: k = Hydraulic conductivity of the soil
H = Total hydraulic head
Nf = Number of flow channels between streamlines
Np = Number of equipotential drops

The hydraulic conductivity of the soil was assumed from in-situ slug test results within groundwater
monitoring wells within the site saprolite and bedrock soils. The maximum measured hydraulic conductivity
of 1.2 x 10-3 cm/sec (3.40 ft/day) was conservatively assumed.

Sediment Basin Drained to Toe of Slope @ Elevation 1886 feet Above MSL

The flow net for the full sediment basin shows a fluid supply rate q = 4.65 ft3/day/ft. Based on this fluid supply
rate, we calculate the required conductivity as:

𝑘𝑜𝑑𝑜=
4.65𝑓𝑞3
𝑐𝑎𝑦
𝑓𝑞
⁄
(0.16)∗(4 𝑓𝑞2)

𝑘𝑜𝑑𝑜=7.27 𝑓𝑞/𝑐𝑎𝑦
BLEINC.

Underdrain Drainage Analysis BLE Project No. J16-9378-06
Buncombe County C&D Landfill
Alexander, North Carolina

Project Name: Buncombe County Landfill – Phase 6 C&D Expansion
Project No.: J16-9378-06
Prepared By: Larry A. Simonson, P.E.
Reviewed By: Gary L. Weekley, P.E.
Reviewed By: Jeff C. Helvey, P.E.
3

Calculation of Factor of Safety:
𝐹.𝑅.=13,123.4𝑓𝑞𝑐𝑎𝑦⁄
7.27 𝑓𝑞/𝑐𝑎𝑦

𝐹.𝑅.=1805

Therefore, the use of No. 57 stone for the proposed cross section of the underdrain system will be sufficient to
drain this condition.

For the selected nonwoven geotextile, the maximum AOS should be 0.25 mm and the minimum permittivity,
0.2 sec-1 based on the percent soil particles passing the No. 200 sieve (silt and clay). Reference AASHTO M288.
From Holtz, et al. (1997); O95 / D85 < B
The lowest D85 for the subgrade soils is 0.6 mm (B-801, 5-15 feet)
Using retention criteria proposed by Holtz (1997), for soils with Cu > 8; B=1
Therefore, O95 < 0.6 mm
Recommend using a 6 osy nonwoven geotextile such as SKAPS GE-160 (or equivalent)
Permittivity: 1.6 sec-1
Permeability: 0.48 cm/s SKAPS GE-160 meets M288 requirements
AOS: 0.21 mm
Thickness: 2.2 mm
Check geotextile permeability
kGT = 0.48 cm/s
ksoil = 1.2 E-03 cm/s (fastest site slug test result)
Factor of Safety (FS) = kGT / ksoil = 0.48 / 1.2 E-03
FS = 400
FS is greater than 100 OK
Check Soil Retention by Geotextile
O95 < (2 to 3) D85 (Reference: Carroll 1983)
0.21 < 3 x 0.6
0.21 < 1.8 OK
For fine grained soils (greater than 50% particles pass No. 200 Sieve):(Reference: Christopher & Holtz, 1985)
Use B-803 1-2.5 feet; D85 = 1.80
O95 < 0.3 x D850.21 < 0.3 x 1.8
0.21 < 0.54 OK
Check Geotextile Clogging
O95 > 3 x D15 Recommend uniform intimate contact between geotextile and subgrade soils.
0.21 > 3 x 0.036 (Reference: Holtz, 1997)
0.21 > 0.108 OK
Prepared by: Gary L. Weekely, P.E.
Checked by: Larry A. Simonson, P.E.
Reviewed by: Jeffrey C. Helvey, P.E.
SELECTION OF NONWOVEN GEOTEXTILE FOR DRAIN
BUNCOMBE COUNTY, NORTH CAROLINA
PHASE 6 C&D
BUNCOMBE COUNTY LANDFILL
BLE Project No. J16-9378-06
Boring Depth % Passing Cu = D60 / D10 Cc = ( D30)2 / (D10 x D60)
No.Feet D85 D60 D30 D15 D10 No. 200 Sieve
B-801 5-15 0.600 0.190 0.030 0.007 0.003 46.7 63.3 1.6
B-802 1-2.5 1.200 0.150 0.023 0.003 0.001 48.8 150.0 3.5
B-802 0-10 6.000 1.300 0.120 0.035 0.018 23.5 72.2 0.6
B-803 1-2.5 1.800 0.062 0.012 0.001 0.001 63.4 62.0 2.3
B-804 2-4 1.200 0.500 0.080 0.020 0.009 28.8 55.6 1.4
B-804 6-7.5 1.100 0.220 0.037 0.036 0.001 40.5 220.0 6.2
B-807 3.5-5 1.200 0.350 0.089 0.024 0.017 26.8 20.6 1.3
B-808S 6-7.5 1.000 0.250 0.070 0.002 0.014 31.4 17.9 1.4
Lowest D85 =0.600
Fine Grained D85 =1.800
Largest D15 =0.036
For a soil to be classified as well-graded and stable with sufficent internal filtration
that limits migration of soil fines, Cu should be greater than 4 and Cc should be between 1 and 3.
Five of the 8 subgrade soils would be described as well-graded and stable.
Prepared by: Gary L. Weekely, P.E.
Checked by: Larry A. Simonson, P.E.
Reviewed by: Jeffrey C. Helvey, P.E.
Gradation Fraction
SUMMARY OF SUBGRADE SOIL GRADATION & PROPERTIES
Phase 6 C&D
Buncombe County Landfill
Buncombe County, North Carolina
BLE Project No. J16-9378-06