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City of Huntington Beach
File #: 20-1475 MEETING DATE: 3/16/2020
Ascon Landfill Site Update
City of Huntington Beach Page 1 of 1 Printed on 3/12/2020
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ASCON LANDFILL SITE UPDATE SLOPE FAILURE CONCERN
I TSC &P,SCON HA '-FVAIUATED TENSIC�,N�,RACY,S ON THE� P'.HV� _�T BFF'M
• December 31'�ASCON Identified Tension Cracks on the Berm alang
CURRENT UPDATES Hamilton.
CLEAN UP EFFORTS HAVE STOPPED. February 6.2020 additional Tension Cracks identified on the Berm
• ASCON IS PURSUING TENTING/ENCLOSURE PERMITS AND DTSC has determined estimated a Medium to High Potential Risk of
WORK PLAN APPROVAL. Slope Failure.
• DTSC and ASCON have evaluated options to repair and alleviate slope
• HAMILTON BERM SIOPE CRACK EVALUATION AND PROPOSED failure.
ACTIONS.
COMMUNICATIONSUPPLEMENTAL
Date:
•"X o
Ascon Landfill Site Slope Inspection TENSION CRACKS IDENTIFIED
NW Berm Geotechnical Observations on Dec 31, 2019
04
TENSION CRACKS IDENTIFIED SLOPE EVALUATION
b EIGHT SLOPE STABILIZATION OPTIONS EVALUATED
SLOPE FLATTENING
T SLOPE FLATTEN j:.'J/Ilr ��,M-ANG ME: :ALLY STABILIZED EARTH
TOE BUTTRESS WITH SOIL
TOE BUTTRESS WITH RETA'!W,11,l'l /dAL,
IN-SITUE SOIL STABILIZATION
t,
SOIL NAILING
o. SLOPE FLATTENING UNDER. A TENT
SLOPE FLATTENING BY MANAGED EXCAVATION.
40
40 40
301
- Q --- ------- ._ 30 ai 30
10 _ 10 w 10,
_. ---- _
" = Approximate Location of Cracking �
° Approximate Location of Cracking - ° 0 c
MSE Wall Geogrid Reinforcement
-1
0`00 0+10 0+20 0+30 OHO 0+50 D+60 0+70 0+80 0+80 1+00 1+10 1+20 1— 1— 1+50 1 1+60 1+70 1+60 - -10 - .
DISTANCE(FEET) 0+00 0+10 0+20 0+30 0+40 0+50 0+60 0«70 0.60 1+ 1«20 1+30 1M0 1+50 1+80 1«70 1+6D 1+90 2+00°
DISTANCE
ANCEE(FEET)
SECTION A-A' SECTION A-A'
40
30 30
2D LL x
a10 — _ - 10� i10
w 0 0 w 0 -
Approximate Location of Cracking oo Approximate Location of Cracking
10+00 0+10 0+2D 0+30 OHO 0+6D .eo 0+70 0+80_-0+90 1+00 1+10 1+20 1+30 1H0 1+50 1+60 1+70 1+80 ,+90 2-M 9-00 0+10 0+20 0+30 0+41 0+50 0+10 0+80 0+90 ,+DD 1+1D 1+20 1. 1H0 1+50 1.80 1+70 1+80 1+90 2+1
DISTANCE(FEET) DISTANCE(FEET)
SECTION A-A' SECTION A-A'
Soil Nailing In-Situ Soil Stabilization
UTILIZES TIE-BACK SYSTEM TO HOLD BACK THE SLOPE FROM cgNslsrs OF STRENGTHENING THE SOILS WIT, •+l!S OF SOIL WITH
COLLAPSING SOLIDIFIED CEMENT.
REQUIRES STABLE AND UNIFORM SOIL TO ANCHOR THE NAILS SCON SOIL IS LINSU1TABLE FOR THIS OPTION.
OR TIEBACKS. The mixture of waste and soil on site is unsuitable to ensure stability
ASCON SOIL IS UNSUITABLE FOR THIS OPTION. This method will add weight to the slope while the concrete/soil mixture is
placed and cures increase the failure risk.
Intermixed soil is non-uniform requiring extensive soil sampling for design
• This solution would be temporary and require continued monitoring of the slope
Current soil is iow-strength and unable to support soil nails movement.
Continued monitoring of the slope would continue concern of collapse EXTENDED TIME FRAME REUUIRED FOE'DESIGN AND MJBILIZATIGN.
FYTE11DED TIMF FF.AME FOR REQUiRFD DESIGN AND MOBILIZATION
40 40 40 ,D
311 ai 30 30 - 30
a --- -- --
20 O 20 LL LL p O x 20
� rGlf
W W
�0 Approximate Location of Cracking D - Approximate Location of Cracking o
-W00 o+ 0+2D 0+30 0D 0+50 0+00 0.70 0a80 0t00 ,+00 ,No 1+2D ta30 1N0 1+50 1+80 ,No 1+60 1+90 z+ODO .,o ,o
w H
0 00 0+10 o.zo 0+30 o a o+eo o+eo 0+70 0.90 owo 1+00 1+10 1+20 1+30 1H0 1+60 1+60 1+70 , ao ,sD 2+00
DISTANCE(FEET) DISTANCE(FEET)
SECTION A-A' SECTION A-A'
Slope Stabilization
Recommendation ASCON LANDFILL SITE UPDATE
DTSC IS RECOMMENDING THE MANAGED SLOPE EXCAVATION NOW TO FIf IL
DUE TO THE FOLLOW REASONS: HTTPS://ASCONHB.COM/
EXPEDITED STARTING SCHEDULE TO MITIGATE SLOPE SIGN-UP FOR EMAIL UPDATES ON THE WEB PAGE.
INSTABILITY PUBLIC HOTLINE FOR NON-EMERGENCY INFORMATION:(714)388-1825
SHORTEST REMEDY FOR A PERMANENT SOLUTION
METHODS USED TO MITIGATE THE ODOR WOULD INCLUDE
Managing the about of excavation performed daily
Utilize Odor Controls (foam, soil,and plastic covering)