SLIDE 1 CUTOFF WALL CONSTRUCTION TECHNIQUES
By Louay M. Owaidat
Great Lakes Environmental & Infrastructure, LLC Levee State-of-the-Practice Symposium
April 22, 2016
SLIDE 2 Over 6,000 miles of levees in Sacramento During Floods – If serious seepage develops, then boils may develop
and failure may occur
Since 1990, the Corps, DWR SAFCA and other local agencies have
launched a levee strengthening program
BACKGROUND
SLIDE 3 1990 Test Section / 4 Methods Sacramento Urban Area Program Marysville / Yuba City Projects (Including Three Rivers Levee
Improvement Authority and Sutter Butte Flood Control Agency)
American River Common Features Natomas Levee Improvement Program Marysville Ring Levee West Sacramento Pocket Delta
SACRAMENTO AREA SLURRY WALL HISTORY – 1990 To Present
SLIDE 4
REASON FOR THE LEVEE REPAIRS
SLIDE 5
TO PREVENT THIS: LEVEE FAILURE
SLIDE 6
TO PREVENT THIS: LEVEE FAILURE
SLIDE 7
TO PREVENT THIS: LEVEE FAILURE
SLIDE 8
TO PREVENT THIS: LEVEE FAILURE
SLIDE 9
Cutoff Wall Construction Technologies
Trench Re-mixing and Cutting Deep Wall Method (TRD) Cutter Soil Mix Method (CSM) Deep Soil Mix Method (DSM/DMM) Conventional Excavation Method (CEM) Long Stick Excavator Clamshell Excavation Method
OVERVIEW
SLIDE 10
Cutoff Wall Types and Quality Control
Soil-Bentonite (SB) Soil-Cement-Bentonite (SCB) Cement-Bentonite (CB) Self Hardening Alternative Methods Slag Cement-Bentonite Soil-Attapulgite Cement-Attapulgite Other
OVERVIEW (CONTINUED)
SLIDE 11 Slurry trench excavation involving excavation utilizing conventional and
specialized long stick excavators
Capable of excavation up to 95 feet Deeper excavations performed utilizing clamshell buckets (over 95 feet) Excavation performed under an engineered fluid (bentonite slurry) for
trench support
Requires separate ex-situ backfilling mixing operation performed using
track dozers and small excavators
Backfill is placed at lead-in trench or tremie placed and progressively
displaces trench slurry
CONVENTIONAL EXCAVATION OVERVIEW
SLIDE 12
CONVENTIONAL EXCAVATION EQUIPMENT
SLIDE 13 TYPES OF CUTOFF WALLS
Cement-Bentonite Others
Soil-Bentonite Soil-Cement-Bentonite
SLIDE 14
Constructed utilizing all cutoff wall construction technologies Permeability of 1 x 10-6 cm/sec or less Soil can be remixed (if clean and suitable) and used in
backfill material
Approximately 20% spoil disposal required No structural strength Requires capping to support loading above the trench
SOIL-BENTONITE (SB)
SLIDE 15
Constructed utilizing all cutoff wall construction technologies Permeability of 1 x 10-6 cm/sec or less Soil can be remixed (if clean and suitable) and used in
backfill material
Approximately 20% spoil disposal required Provides minimal strength (30 – 300 psi) Capping required for curing and protection of cutoff wall
SOIL-CEMENT-BENTONITE (SCB)
SLIDE 16 Constructed utilizing conventional excavation technology Permeability of 1 x 10-6 cm/sec or less Self hardening slurry; requires no separate backfilling
- perations; suitable in areas with limited equipment access;
depth limitations
100% trench spoil disposal required Provides minimal strength (30 – 300 psi) Capping required for curing and protection of cutoff wall
CEMENT-BENTONITE (CB)
SLIDE 17 SLURRY CUTOFF WALLS
DEFINITION: SUBSURFACE WALLS THAT ACT AS BARRIERS TO LATERAL FLOW OF GROUNDWATER AND WATERBORNE CONTAMINANTS
SLIDE 18
SLURRY TRENCHING TECHNIQUE
SLIDE 19
SLURRY TRENCHING TECHNIQUE
SLIDE 20
SLURRY TRENCHING TECHNIQUE
SLIDE 21
SLURRY TRENCHING TECHNIQUE
SLIDE 22
SLURRY TRENCHING TECHNIQUE
SLIDE 23
SLURRY TRENCHING TECHNIQUE
SLIDE 24
SLURRY TRENCHING TECHNIQUE
SLIDE 25
HYDRAULIC BARRIERS SLURRY CUTOFF WALLS
SLIDE 26
- Soil-Bentonite
- Soil-Cement-
Bentonite
- Cement Bentonite
- Composite walls
- Plastic Concrete
HYDRAULIC BARRIERS SLURRY CUTOFF WALLS
SLIDE 27
CASE STUDY
Cement/Slag Cement Bentonite Cutoff Wall
SLIDE 28
American River Common Features Project Sites L8 and R8
SLIDE 29
BATCH PLANT / STAGING AREA
SLIDE 30
BATCH PLANT / STAGING AREA
SLIDE 31
28 DAY HYDRAULIC CONDUCTIVITY OF 1X10-6 cm/s 28 DAY UNCONFINED COMPRESSIVE STRENGTH OF
50 – 300 PSI
LEVEE RESTORATION - AFTER15 PSI WAS ACHIEVED 10 DIFFERENT MIX DESIGNS WERE EVALUATED
CB SLURRY MIX DESIGN
SLIDE 32
SLURRY BATCHING OPERATION
BENTONITE SLURRY SLAG CEMENT PORTLAND CEMENT POLYMAX CB MIXING TANK
SLIDE 33
SITE L8 – BATCHING OPERATION
SLIDE 34
CEMENT BENTONITE CUTOFF WALL PANEL CONSTRUCTION
SLIDE 35
SLIDE 36
SLIDE 37
SLIDE 38
SLIDE 39
OVER 5,500 MAN HOURS WITH ZERO LOSS TIME
ACCIDENTS
CB WALL EXCEEDED SPECIFICATION REQUIREMENTS PROJECT COMPLETED ON TIME PROJECT COMPLETED UNDER BUDGET
CONCLUSION
SLIDE 40
US ARMY CORPS OF ENGINEERS – SACRAMENTO
DISTRICT
HDR SACRAMENTO AREA FLOOD CONTROL AGENCY
(SAFCA)
DEPARTMENT OF WATER RESOURCES (DWR) ASCE – SACRAMENTO SECTION
ACKNOWLEDGEMENTS
SLIDE 41
The trench remixing and deep wall (TRD) method is a
process for excavation and in situ mixing.
The TRD method has been widely employed in Japan Utilizes a large revolving chain and cutter bar, which is
lowered down to design depth of the cutoff wall and then moved in horizontal direction
TRD equipment simultaneously excavates and mixes in situ
soils and added slurry resulting in a continuous soil mixed wall.
TRD OVERVIEW
SLIDE 42 TRD wall installation can consist of two steps
Pre-trenching using bentonite slurry to stabilize the trench Wall production by adding cement grout to the soil-bentonite mixture
in the pre-trenched zone.
TRD equipment, in general, requires a very high
maintenance cost due to the need for frequent repair of cutter
TRD OVERVIEW (CONTINUED)
SLIDE 43
TRD METHOD
SLIDE 44
TRD EQUIPMENT
SLIDE 45
Cutter soil mixing (CSM) provides for the construction of
retaining and cut-off walls by mixing soil in-situ with a cement/bentonite grout
The CSM wall consists of adjacent primary and secondary
panels
The CSM wall is constructed using equipment derived from
diaphragm wall cutter technology
Consists of cutting and mixing drums mounted on compact
hydraulic motors
The positioning and verticality of the wall is achieved using
a kelly bar
CSM OVERVIEW
SLIDE 46
CSM METHOD
SLIDE 47
CSM EQUIPMENT
SLIDE 48
Deep Soil Mix Method (DSM/DMM) has been utilized in
United States since 1986
Process involves in-situ mixing utilizing multiple augers
(3 to 6)
Depth capabilities in excess of 200 feet Applications include excavation support, under seepage
cutoff, liquefaction mitigation and other ground improvement
DSM/DMM OVERVIEW
SLIDE 49
DSM/DMM METHOD
SLIDE 50
DSM/DMM METHOD
SLIDE 51
DSM/DMM METHOD
SLIDE 52
DSM/DMM METHOD
SLIDE 53
DSM/DMM EQUIPMENT
SLIDE 54 CASE HISTORY
CALPERS Headquarters Expansion 3rd and Q Streets Sacramento, CA
SLIDE 55
12 miles of slurry walls (3.6 million sf) Maximum depth to 80 feet Permeability Requirements: 5 x 10-7 cm/sec Strength Requirement: 30 psi Residential and commercial areas
SACRAMENTO, CA
SLIDE 56 CALPERS HEADQUARTERS SITE PLAN
NUMBER AND DIMENSIONS DEPENDENT ON SPOILS MANAGEMENT
Q STREET R STREET 3RD STREET
5TH STREET
N
Min 50' - 0" (Typ)
EXISTING ALLEY 4TH STREET
A A
50' MIN. C L
CUTOFF WALL
2% MAX 1/20
SECTION A - A WORKING PLATFORM (TYP)
1 1
9'
40' 50' 20'
SOIL-CEMENT WALL SOIL-CEMENT WALL
BATCH PLANT #2
N
BATCH PLANT #1
WORKING PLATFORM
SPOILS COLLECTION AREA (TYP.)
40' Min 9' - 0"(Typ)
CUTOFF WALL INSTALLATION STARTING POINT PRE-DRILLING STARTING POINT
MATERIAL DELIVERIES ACCESS ROUTE
SLIDE 57
CASE HISTORY
SLIDE 58
CASE HISTORY
SLIDE 59
CASE HISTORY
SLIDE 60
CASE HISTORY
SLIDE 61
CDSM BATCH PLANT
SLIDE 62
SLURRY PREPARATION
SLIDE 63
SLURRY PREPARATION
SLIDE 64
DSM CORE SAMPLES
SLIDE 65
TEST SPECIMENS PREPARED FROM CORE SAMPLES
SLIDE 66
CDSM PANEL
SLIDE 67
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SINGLE PASS TRENCHING METHOD
SLIDE 69
SINGLE PASS TRENCHING METHOD
SLIDE 70
SHEET PILE WALLS
SLIDE 71
Focused Applications: Temporary Excavation Support/Seepage Control
For Environmental Applications
Permanent Seepage Barrier For Environmental
Applications
Used In Conjunction With Other Systems:
Jet Grouted Bottom Seal Rock Grout Curtains Funnel And Gate Treatment Systems
SHEET PILE WALLS
SLIDE 72
Conventional Hot and Cold rolled sections with interlock
sealants
WaterlooTM Barrier HDPE and Vinyl Sheets
SHEET PILE WALLS SYSTEMS
SLIDE 73
BELLE WV
SLIDE 74
DISCUSSION POINTS
SLIDE 75 Design Intent Applicable Construction Method/Site Condition Risk Analysis/Cost Uniform Specifications Lessons Learned Experience/Qualifications Permits Water Community Involvement
DISCUSSION POINTS
