Case History Los Angeles, California

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Case History Los Angeles, California
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Los Angeles from East LAMetro Gold Line Eastside
Extension(MGLEE, LRT)
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Metro Rail System

• Local and general plan of the Los Angeles LRT
  system including the Gold Line Extension into
  East Los Angeles

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LA Metro Gold Line Extension

• Project Plan

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LA Metro Gold Line Extension

• Underground Segment
• 9,400 feet twin tunnels
• Two portals
• Two cut-and-cover segments
• Two stations
• Twin bored tunnels
• Six cross-passages
• Two sump structures (now combined)
• At-Grade 5 miles

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LA Metro Gold Line Extension

• Overall Planning, Design and Construction
  Schedule 20 years!

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Methane Zone Created in 1985

• Ban lifted in 2006 due to EPB/Slurry Technology

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MGLEE Planning Overview

• Originally Planned as A Redline subway
• The Final EIS/EIR Approved in 1994
• Preliminary Final Design 1996-1998
• 1998 MTA suspended work on all rail projects
• Funding Shortfalls
• Prop A and C no local funds for subway

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MGLEE Planning Overview, cont.

• 1999-2001 Major Investment Study authorized for
  current project - includes
• BRT, Light Rail, Heavy Rail, 8 Alignments
• Preferred Alternative
• LRT, Union Station Alameda First Street,
  Indiana, 3rd to Pomona/Woods
• Tunnel through Boyle Heights
• State certification February 28, 2002
• Federal ROD March 2002
• IFB July 2004
• Scheduled ROD 2009

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Suspended vs. Current Project
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Project Setting
Los Angeles Union Station
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Platform at Union Station

• Retaining wall at 101 Freeway

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Historic 1st Street Bridge
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4th Street Bridge Los Angeles River
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1st Street Bridge Retrofitting - 1996
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101 Freeway Overcrossing
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1st/Boyle (Mariachi) Station
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1st/Soto Station Area
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Soto Street
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Neighborhood Residential, Light Commercial
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MGLEE Design

• Suspended and Current Project
• Geotechnical Investigations
• TBM Specifications
• Tunnel Lining requirements
• Seismic Conditions and Fault crossing
• Gassy Ground
• Building protection

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Geology/Subsurface Conditions

• Tunnel entirely within alluvium (Pleistocene and
  Holocene) Interlayered sands and clays
• Fine-grained soils predominantly stiff to hard
  low plasticity clay and silt
• Coarse-grained soils predominantly dense to very
  dense silty sand and clayey sand
• Occasional Cobbles and potential for boulders
• Underlain by Tertiary age highly weathered
  siltstone and claystone bedrock
• Former oil field

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Geologic Profile
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Former Oil Producing Area
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Environmental Conditions (GBR)

• Anticipated Tunnelling Conditions
• Soil Approx. 32,000 CY contaminated
• Groundwater 500 gpm at 1st/Soto site
• USTs at 1st/Soto site
• Methane max. 100,000 ppm (LEL is 50,000 ppm)
• H2S none detected (0.2 ppm is the limit of
  field detection equipment), but 0.002 ppm can be
  detected by smell

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TBM Specifications

• Geologic Profile
• Wide range of conditions including Boulders and
  Cobbles
• Groundwater levels
• Probing drilling for Gas (OSHA req.) and grouting
• Screw Conveyor only no open mode
• New or Used TBMs
• Compressed Air to access face

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Allowable Surface Settlement
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Differential Settlement, above tunnel
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Tunnel Cross Section

• Precast Concrete Tunnel linings,
• 20 ft Diam.

2.6m (I.D)
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Full Scale Testing at U of I

• Previous Metro Tunnels had initial and final
  support with HDPE Gas and Water Barrier
• Seismic Conditions
• Gassy Ground

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Gas Leakage Testing of Gaskets
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Developed Double Gasket Design with Convex to
Convex joints
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Convex to Convex Radial Joints
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After Compression Testing
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Cyclic Loading Test and
Subsequent Leakage Test
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Test configuration Cyclic Tests
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Buried Thrust fault Topographic Expression
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Seismic Design Criteria

• Probabilistic
• ODE 200 years
• MDE 2,000 years
• Tectonic 2,800 3,900 years
• Add tectonic movement to shaking distortion
  (conservative)
• 0.6 inch over 45 feet scaled linearly for length
  height of station (MDE)

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Summary of Seismologist and Geotechnical
Investigation

• Oskin et al. 2000
• Blind fault producing Coyote Pass Escarpment is
  shallow ( 500 m)
• Fault slip rate incremental vertical growth of 2
  2.8 feet per seismic event

• ECI investigation
• Alluvial sediments gently folded into a
  asymmetric syncline
• Sharpness of hinge

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Coyote Pass Feature
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Interpretive Conditions
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Section along Soto Street
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Cross section at Soto Street
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Open Book Model Free-field vs. Soil-Structure
Interaction
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Thrust Model Free Field vs. SSI
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Building Protection
Typical building protection plan along the tunnel
route for the East Side LRT Extension survey of
over 200 bldgs
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Compensation Grouting

• Designed for about 40 Structures

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Compensation Grouting Plan
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Permeation Grouting

• Used at Breakouts and Cross passages

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Construction
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101 New Bridge March 06
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Bridge June 9, 2006
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101 New Bridge February 07
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LA Metro Gold Line Extension
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West Portal Excavation- Cut and Cover
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Mariachi (Boyle) Station Plan
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Initial Excavation at Soto Station
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Deck Beam Placement - Soto
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Precast Concrete Decking
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Mariachi Plaza Excavation and Mining Shaft
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60 ft Excavation at Mariachi Complete Aug 2005
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TBMs at Herrenknect Plant
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Views of TBM (new)
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Screw Conveyor Fabrication
Fabrication of the screw auger for conveying
tunnel muck from the cutterhead
Fabrication the screw auger barrel in sections
for site assembly
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Screw Conveyor on Machine
Worlds longest
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TBM 60 m screw conveyor
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TBM Assembly
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TBM Assembly in Shaft
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TBM Trailing Gear
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TBM Operators Cabin
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Segment Casting
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Double Gasket Segments at TBM heading
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Muck Handling
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Conditioned Soil
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Tail Seal Grout Ports
Two Ports at four locations around shield
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Wire Brushes after 1st Drive
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TBM Hole Through Nov 06, 2007
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West Bound Machine Dec 2007
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TBM Disassembly
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TBM Disassembly
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Lifting Shield from Shaft
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Cutterhead Transport
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Cross Passage Excavation
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Pipe Arch Drilling
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Cross Passage Excavation
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Compensation Grouting Used HDD
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Compensation Grouting - HDD
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Chemical (consolidation) Grouting
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Instrumentation and Monitoring

• Ground surface
• Ground Above Tunnel
• TBM Parameters

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Ground Surface Survey
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Typical Settlement TroughCummings Street
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Instrumentation-ground monitoring with MPBX
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MPBX Monitoring
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Typical Extensometer
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MPBX performance vs Typical
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Earth Pressure

• pH (68.64 Hw) (1.5 .25 ? B), in
  which
• pH theoretical required pressure
• Hw hydrostatic head
• ? unit weight of the soil
• B diameter of the bore

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Instrumentation, ADS

• Pressure
• Advance

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Instrumentation, Grout Volumes
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TBM Progress Rates

• Avg EB 37 ft/day, max 91
• Avg WB 44 ft/day, max 96

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The End
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Dewatering
Simulated ground water drawdown at the Soto
Street Station excavation
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Backfill Grout System
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Section thru Crosspassage