10s-allam muro colado

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June 27, 2013

BLUE PLAINS TUNNEL PROJECT

DC Clean Rivers Project

District of ColumbiaWater and Sewer Authority

DCWater Blue Plains CSO TunnelWashington, DC

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• Traylor/Skanska/Jay Dee Joint Venture• Halcrow Inc., A CH2M Hill Company• Bencor Corporation a wholly owned subsidiary of Layne

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DCWater Blue Plains CSO TunnelWashington, DC• The Blue Plains Tunnel is 23’dia. and 23,600’ (4.5 miles) long including 5

shafts along the alignment on the east side of the Potomac/Anacostia River:

• Blue Plains Tunnel Discharge Pumping Station (2 shafts combined)• DS-Dewatering Shaft finished 132’ Dia 194.5’ deep.• SS-Screening Shaft finished 76’ Dia 176’ deep.• Bolling Air Force Base Drop Shaft finished 50’ Dia 146’ deep .• Poplar Point Drop Station finished 55’ Dia 139’ deep.• Main Pumping Station Drop Shaft finished 55’ Dia 123’ deep.

Aerial View of the BPT-DS-SS Site


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Diaphragm Walls•Access for deep tunnel•Soft ground

Other Option Considered•Ground freezing

Reason for Choosing D-Walls•Cheaper•Faster•Less Risky•More Available Contingencies

Typical Construction Procedure:• Develop Detailed Engineering Design• Site Preparation• Guide Wall Construction• Excavation• Desanding• QA/QC, Verticality Control & Verification• Reinforcing Element Fabrication & Placement• Concrete Placement • QA/QC Post Installation


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Ground Conditions

• Fill• 25-36 ft. deep, coarse silty sand w/gravel

• Alluvium• 17-25 ft. thick, clay to gravel• Consolidated under it’s own weight

• Potomac Group – Patapsco/Arundel Formation (P/A)• Below 51’ Dense hard soils• Stiff to hard silt/clay• Interlayers of sand/gravel

• Potomac Group – Patuxent Formation – (PTX)• Dense hard soils• Mostly sand/gravel w/interlayers of hard

silt/clay

Groundwater• Upper Aquifer – 20-30’ below ground surface• Lower Aquifer – 35’ below grade at El. -20’ MSL

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• REQUIREMENTS• 100 year design life• Permanent ground loads

& 500 year flood level

• RESULTS• 7,000psi @ 56d• Steel fy = 60ksi• Minimum Cementitious

575 lb/yd3• w/cm ratio 0.4• High slag/fly ash

replacement• Min. cover requirement

6”

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Develop Detailed Engineering Design

Designing and working out all of the details in advance will pay off with a smoother installation and minimize delays.



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BPT - Shaft

• DS Shaft 139’ Dia.• SS Shaft 81’ Dia.

• Wall Thickness – 5’• Joining Wall – 8’-

18’

• D-Wall Panel Depth 194.5’

• Max Excavation 190’

Excavating inside the shafts

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117/2/2013

BPT - Shaft

• D-Wall 5’ thick• DS CIP – 3’

thick• SS CIP – 2’

thick

• Base Slabs• DS – 25’ thick• SS – 16’ thick

Design Profile of DS and SS Shafts

DCWater Blue Plains CSO TunnelWashington, DCComparison Prediction vs. Field Measurement

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Plaxis 3DFE Mesh Shaft Wall

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DCWater Blue Plains CSO TunnelWashington, DCComparison Prediction vs. Field Measurement

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Lateral Wall Deflection max.Plaxis 3D =0.5”Inclinometer= 0.3”

Max. deflection occurs above the excavation level.


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Instrumentation for D-Walls Construction

• Inclinometers• IPI – In-Place Inc• Manual Incl

• SMPs• GMPs• UMPs• Piezometers• Extensometers

Instrumentation Around DS and SS Shafts

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Total Stress Cells


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Concrete Strain Gauges Rebar Strain Gauges

Coring Sample from Panel C-2

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DCWater Blue Plains CSO TunnelWashington, DCCHALLENGES• Heavily over-consolidated soils• Design req’d 60” wide panels• Design req’d 54” continuous wall

min and 96”for middle wall.• Tolerance of .12% for panel

deviation

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DCWater Blue Plains CSO TunnelWashington, DCCHALLENGES

• Y-Panel• Clay Soils

• Req’d centrifuges• Rebar

• 1,250 tons of rebar in DS & SS shafts

• Picks of 50 tons• GFRP at tunnel eyes• Slab Dowels

• DS - 2,620 slab dowels installed in 8’ shear key at the bottom for the base slab

• Concrete• 30,000 CY of tremie• 1,000 CY single tremie

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Diaphragm Walls for Tunnel Shafts

Why use diaphragm walls in tunnel shaft construction?

The extensive use of Tunnel Boring Machines (TBM) for modern tunnel construction has produced the need for deep access shafts to allow for the lowering and removal of these machines. These shafts must be as deep as the new tunnels. Diaphragm walls installed in a circular shape have been proven as an efficient and cost effective solution for deep shafts in soils over conventional methods. These diaphragm walls can be installed using clamshells & hydromills. For deeper shafts the hydromill has proven itself as an effective tool for quickly installing diaphragm walls into any type of soil and rock so it has also been accepted as the cost effective solution for these types of deep shafts:Significant depth walls are feasible with diaphragm walls using hydromills.

Hydromills can install diaphragm walls with large wall thickness (1.5m+) to support large compressions loads as required for very deep shafts.

Can readily excavate through any rock formation and boulders.

High rate of production can permit projects to be completed much faster than conventional methods.

Brightwater Conveyance System Seattle, WA

West/East Side CSO Portland, OR

Edison Force Main, Middlesex Co, NJ

Riverbank Filtration Louisville, KY

Bay Division Pipeline Bay Tunnel, San Francisco, CA

Port Mann Main Water Supply Tunnel, Vancouver, BC

Deep Rock CSO Tunnels, Indianapolis, IN

Lower Harbor Brook CSO , Syracuse, NY

DCWASA Blue Plains CSO Tunnel, Washington, DC

Recent Projects Performed by Bencor a subsidiary of Layne

RECENT TUNNEL SHAFT PROJECTSUSING HYDROMILLS

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DCWater Blue Plains CSO TunnelWashington, DCMobilization of 2 Hydromills and 2 Buckets sized for this job 60” thick


Equipment excavating at BPT-DS-SS Site

2 Hydromills & 2 Buckets

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Verticality Checking to meet tolerances of 0.125% (3 inches maximum deviation over 195 feet depth

Koden reader and output


Analysis of collected verticality data

Closing panel verticality compared to adjacent primary panels installed

-40-30

-20-10

010

2030

40

-5-6-7-8-9-10

-11

-12

-13

-14

-15

-16

-17

-18

-19

-20

-21

-22

-23

-24

-25

-26

-27

-28

-29

-30

-31

-32

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-34

-35

-36

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-38

-39

-40

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-54

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-60

OF

F C

EN

TE

R, in

DE

PT

H, m

P-17 Towards DS Shaft P-17 Away from DS Shaft C-18 Towards DS Shaft C-18 Away from DS Shaft

Tow

ards A

way

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BPT- Cutoff Wall for TBM Breakout


Shaft ID = 139’ (42.4m)Depth = 194.5’ (59.3m)Thickness = 60” (1.5m)

Shaft excavations now completed

BPT- Discharge Pumping StationShaft Plan


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Shaft Section


Reinforcement Details


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Guide wall excavation and construction

BPT-DS-SS


5ft thick panel excavation using hydraulic clamshells & hydromills

BPT-DS-SS


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Desanding plant must be sized to produce the required slurry for a safe and efficient project

Slurry Desanding Plants


Vertical Tanks – used when limited space is available

Slurry Storage


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Slurry storage ponds are used if site conditions permit and if very large quantities of slurry are required

Slurry Storage


Slurry desander in operation at the Blue Plains Tunnel


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Full length reinforcing cages for typical primary panels are fabricated on site.


Y Panel Rebar Cage fabricated on site.

Rebar Cages for Middle Wall and Y Panel


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Middle Wall Rebar Cage built with 3 layers of reinforcement

Rebar Cages for Middle Wall


Full length reinforcing cages are lifted into place


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Concrete placed using multiple tremie pipes to complete 1032 cy “Y” panels in 10 hours


BPT- Dewatering Shaft being excavated


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BPT- Dewatering Shaft & Screening Shaft 1/3 excavated


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Lowering TBM into position inside completed shaft


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Lowering TBM into position inside completed shaft


Bolling Air Force Base Shaft Under Construction

BAFB Shaft Plan

Shaft ID = 55’ (16.8m)Depth = 148’ (45.1m) Thickness = 42” (1.1m)


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Poplar Point Shaft

Aerial View of the PPJS Site


Poplar Point Shaft

Aerial View of the PPJS Site


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Poplar Point Shaft

PPJS Site Preparation Guide Walls Construction


Poplar Point Shaft Under Construction

PPJS Shaft Plan



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Poplar Point Shaft Under Construction


Main Pumping Station Dewatering Shaft

Aerial View of the MPS Site


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MPS Shaft Plan

Main Pumping Station Dewatering Shaft



DCWater Blue Plains CSO TunnelWashington, DCLESSONS LEARNED

• Utilizing D-Wall in Permanent Structure• Req 100-yr design• Concrete cover• More Rebar• Cementitious content• Concrete comp. strength• Tolerances

• Excavating in stiff Clays• Desanding & centrifuges• Disposal challenges• Bentonite vs. Poly blends

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LESSONS LEARNED

• Excavation• Dry

• High production• Easily repair

voids/bulges• Wet

• Slower production• More complicated• Unknown wall

condition• Repairs postponed

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10s-allam muro colado

Documents

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dc11722013bpt shaft

dsdewatering shaft

ssscreening shaft

thick ds cip

thick ss cip

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d steel