Soft Ground Tunneling through Contaminated Groundwater

Transcription

1 5 th Annual Technical Forum GEOHAZARDS IN TRANSPORTATION IN THE APPALACHIAN REGION Soft Ground Tunneling through Contaminated Groundwater Nasri Munfah P.E. and Subal Sarkar P.E. Parsons Brinckerhoff, New York NY August 3 4, 2005

2 East Side Access Project Connection of the Long Island Rail Road to Grand Central Terminal in New York $6.3 Billion Project

3 ESA Will Bring LIRR Riders Where They Want to Go Penn Station on West Side is only LIRR terminal in Manhattan Over 53% of LIRR s s current 240,000 riders into Penn Station are bound for destinations on the East Side of Manhattan Requires transfer to crowded subways, taxi or minute walk ESA will save 30 min/day for LIRR East Side customers

4 Project Components 8,600ft 5,500ft 4,400ft 1,600ft

5 In Manhattan: Tunnels and a New Rail Terminal Metro-North Railroad Park Ave Tunnel NYCT 60th Street Tunnel (N and R) New LIRR Tunnels

6 Manhattan Segment 38th St Vent Plant 53 rd Street Cross-Over Caverns 57 th Street Station Caverns 55th St Vent Plant TBM Single Track 145 ft. at 2nd Ave 125 ft. at GCT Wye Caverns 60th Street TBM Single Track

7 Grand Central Terminal

8 ESA GCT Caverns and Shafts GCT Station

9 Grand Central Terminal Caverns Vanderbilt Avenue Park Avenue MNR Upper Level MNR Lower Level Off Street Entrances LIRR Concourse Freight Elevators Passenger Elevators Escalator Shafts LIRR Mezzanine Upper Platform Cross Section Looking North Elevators Cross Section Looking North Terminal Caverns Lower Platform

10 Grand Central Terminal Caverns West Cavern East Cavern Typical Section Thru Caverns

11 Mid-Level Mezzanine Grand Central Terminal - Renderings Lower Train Room

12 Grand Central Terminal - Renderings Ticketing and Waiting Concourse and Circulation

13 Challenges in Manhattan Progressing tunneling with minimal community impact Coordinating work in GCT with Metro-North operations Minimize impact on NYCTA Operations No Adverse Impact on Existing Facilities

14 Maintain Business as Usual

15 Geological Zones The Manhattan Segment Was Subdivided Into Seven Geotechnical Zones

16 Tunneling in Manhattan Hard Rock Tunnel Boring Machine (TBM) Drill and Blast Roadheader Cavern Construction

17 Initial Support Rock Bolts and Dowels Straps, and Mesh Lattice Girders and Shotcrete Ribs and Lagging

18 Final Liner Waterproofing System Drained with PVC Membrane Cast-in in-place Concrete

19 In Queens: Tunnels, Tracks and Yards In Queens: Tunnels, Tracks and Yards TBM Launch Wall Track A Track B/C 39 th St th St Cut & Cover TBM Honeywell Honeywell St Sunnyside Yard Amtrak Bldg 4 Track D LIRR Lead Mid-Day Storage Yard Westbound Bypass Amtrak Bldg 3

20 Queens Project Site Queens Project Site Queens Blvd Queens Blvd Sunnyside Yard 39th Street LIRR/Amtrak LIRR/Amtrak Main Main Line Line

21 The Challenges in Queens Tunneling Under The Busiest Rail Yard In The Country Maintaining LIRR And Amtrak Service For Over 740 Trains Through Harold Tunneling Adjacent To Contaminated Ground Tunneling In Mixed Face Conditions Tunneling In A Difficult Ground Under High Water Table Protecting Existing Structures

22 Queens Tunnels

23 Queens Tunnels

24 Queens Tunnels

25 Queens Tunnel

26 Queens Tunnels

27 Queens Tunnels

28 Queens Tunnels

29 Queens Tunnels Geological and Hydrological Conditions Heterogeneous Fill Glacial Outwash Deposits - Boulders Glacial Till Compressible Organic Soils Mixed Face Rock - Gneiss High Water Table Soils and Groundwater Contamination Typical Boulders

30 Environmental Conditions Soil Contamination Petroleum, Coal Ash, Cinder Lead, Asbestos Ground Water Contamination VOC, SVOC PCB BETEX

31 Existing Environmental Conditions VOC Plumes BTEX plumes PCB Plume VOC/SVOC Plumes VOC Plumes

32 Hydrological Numerical Modeling Design Phase Planning Tool 3-D D Steady State Flow Model Analysis Sensitivity Analysis Correlation with Field Observation Estimate potential effects of construction on contaminant plumes Permit application preparation Results Drawdown is Limited to 2ft Hydraulic Gradient No Anticipated Movements of the Plumes

33 Results of Fate & Transport Modeling

34 Structural Measures Cut and Cover Slurry Walls Cutoff Walls Jet Grouting Bored Tunnels Pressurized Face TBM Precast Segmental and gasketed Liner Annular grouting Instrumentation and Monitoring

35 Cut and Cover

36 Bored Tunnels A B/C D Yard Lead Section Through Launch Shaft : Rock/Soil Interface

37 Length of Tunneling Track A Track B/C Track D Yard Lead Glacial Till Glacial Till Rock & Mixed Face Glacial Till Rock & Mixed Face Glacial Till Section Length Tunnel Length 2,180 ft 2,180 ft 1,739 ft 60 ft 2,158 ft 2,218 ft 415 ft 3,969 ft 1,739 ft 4,384 ft 10,523 ft 10,523 ft

38 Pressurized Face TBM Earth Pressure TBM Slurry TBM

39 Slurry TBM

40 Earth Pressure TBM

41 Tunnel Liner Precast Segmental Gasketed Liner Annular Grouting Caulking and Sealing

42 Segmented Liner Tunnel

43 Environmental Measures Structural Design to Minimize Drawdown Ground Water Treatment Plants Sedimentation Tanks Oil/Water Separators Filtration FlocculatioCarbon Absorption Sampling/Testing Instrumentation & Monitoring Disposal

44 Instrumentation and Monitoring Pizometers Ground Water Monitoring Wells Elevation Quality Potential Movement of the Plumes Ground Water Sampling and Testing Mitigation Measures

45 Conclusions State-of of-the Art Design Concepts Latest Construction Techniques and Technologies Careful Attention to Environmental Issues Measures to Prevent Movement of Plumes Extensive Monitoring and Instrumentation Program Safe Guard of the Public Health and the Environment