Deep Tunnel System

ovariesracialUrban and Civil

Nov 25, 2013 (3 years and 9 months ago)

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City of Indianapolis
Deep Tunnel System

September 12, 2013


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Presentation Overview


CSO Deep Tunnel System



Efforts to Date



Tunnel Project Evaluation Overview


Geotechnical Investigations


Groundwater Management Plan (GWMP)


Schedule and Project Requirements


DRTC Construction

Indianapolis’ CSO LTCP Overview


Each year, an average of 6 billion
gallons of combined sewage overflow
into Indianapolis streams


45
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80 times a year, overflows send
bacteria, pathogens and untreated
waste into:


White River


Fall Creek


Pogues Run


Pleasant Run & Bean Creek


Eagle Creek


Lick Creek & State Ditch


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CSOs are a Big and Expensive Problem to Tackle…


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01/15/07

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…BUTT, things could be Worse!


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Indianapolis’ CSO LTCP Overview


City’s CSO Long Term Control
Plan is Multi
-
Faceted and
includes:


Using Existing System
Capacity



Inflatable Dams and Pinch Valves


Constructing New Storage
and Conveyance



Deep Rock Tunnel System



Storage Tanks


Expanding and Upgrading
Treatment Facilities



Belmont AWTP



Southport AWTP


Belmont AWTP


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Deep Tunnel System
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How it Works

CSO to
Tunnel

River

CSO Outfall

Storage Tunnel

Drop Shafts

Consolidation

Sewer

Regulators

Wet

Weather

Deep Tunnel Pump Station
to WWTP

Working Shaft

Combined Sewer

To WWTP

WWTP

CSO to
Tunnel

Combined
Flow to
WWTP and
Tunnel

BEDROCK

SHALE

SOILS


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Master Plan for Indianapolis’ Deep Tunnel System


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Deep

Tunnel

System

Components


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Deep Tunnel System Details


~25 miles long


18
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foot finished diameter


Total System Storage of 250 MG min.


225
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275 feet deep in bedrock


19 drop shafts along FCWRTS


3 drops shafts DRTC


Flows from Lower Pogues Run and Pleasant Run Tunnels


~30,000 feet of connection tunnels


90 MGD deep pump station at Southport AWT



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Construction Timeline for Deep Tunnel System


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Overview
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Geotechnical Investigations


Drilled over 100 Borings Up to 300 Feet Below
Ground Surface


Sampling and Testing of Physical Rock and Soil
Characteristics


Soil and Groundwater
Environmental Screening
and Sampling


Hydraulic Packer Testing
of Bedrock Permeability

Track mounted CME
-
55 drill rig

Logging Bedrock Cores



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Core Storage Facility


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Illustrative Representation of Indianapolis’ Geology


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Limestone Geologic Contact

Contact

Courtesy of Martin Marietta, Kentucky Avenue Mine.

Jeffersonville

Limestone

North

Vernon

Limestone


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Solution Features Can Be Risky!

Courtesy of Martin Marietta, Kentucky Avenue Mine.

Solution

(Karstic)

Feature


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Summary of Geotechnical Findings


Alluvial (Surficial) Soils Ranged from approximately
75


100 Feet Thick


Alluvial Soils = Primarily Sand with some Clay and
Silt Units


Groundwater Table within 25 feet of Ground Surface


High Hydraulic Conductivities in Surficial Soils
based on Pump and Slug Testing


Vertical and Inclined Borings and Rock Cores


Piezometers Set in Vertical Borings


Bi
-
weekly Monitoring of Groundwater Levels


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Summary of Geotechnical Findings


Bedrock Consisted Primarily of Competent Limestone
and Dolomite


Shale Underlying the Alluvial Soil on Southern End of
Tunnel System (DRTC)


Shale Ranges from 6


30+ Feet Thick


Bedrock was Weathered Near Soil/Rock Interface


Bedrock Permeability Fairly Consistent Throughout
Deep Bedrock Layers (150+ Feet BGS)


No High Permeability Zones Encountered Below
Soil/Rock Interface


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Summary of Geotechnical Findings


Rock Quality Designation (RQD) indicates
Bedrock is Sound and Relatively Consistent, and
Not Heavily Fractured (Phase 1A)


Unconfined Compressive Strength (UCS)
averaged 9,000 to 10,000 pounds per square inch
(Phase 1A)


In Summary, Rock is Very Favorable for
Tunneling


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Summary of the Fall Creek/White River
Groundwater Management Plan (GWMP)


Overall Goal of the GWMP was to Evaluate Various Scenarios During
Tunnel Construction and Future Operation to Determine Any Potential
Short
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term of Long
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term Impacts to Groundwater resources


Regional Cooperation to Evaluate and Monitor Groundwater Levels
(Piezometer Readings)


Development and Calibration of an Existing Conditions Groundwater
Model


Alternative Scenarios Evaluation


Groundwater Risk Registry


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Groundwater Model Boundaries


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Profile of Conceptual Groundwater Model


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Alternative Scenarios




Primary Considerations


Concerns During Construction (e.g., encountering
fractures and potential solution features)


Long Term Operational Impacts of Groundwater


12 Scenarios Modeled


Scenarios 1
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3


Expected Conditions During Construction


Scenarios 4
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6


High Infiltration During Construction


Scenarios 7
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9


Expected Conditions During Long Term Operation


Scenarios 10
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High Infiltration During Long Term Operation


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Scenario 1


White River Tunnel Alignment,
Expected Conditions During Construction


Deep
Carbonate
(Layer 4)


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Groundwater Impact Potential (Localized)

White River

Impact to GW Table

Tunnel

Local and Sustainable Project Requirements


Balancing Opportunities and Risk


Not just a Linear Sewer Project
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Large Diameter and Complex
Tunnel Alternative


Incorporate Sustainable Design Features and Operational
Strategies


Green Infrastructure When and Where Appropriate


Begin with the End in Mind (O&M)
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100+ Year System Life
Solution


MBE/WBE/Veteran Involvement and Mentoring


Local Execution of Work Preferred


Meet the Revised Consent Decree Schedule


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Introducing the Clean Stream Machine!
DRTC Project Groundbreaking Event


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DRTC
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Tunnel Boring Machine (TBM)


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Bid


August 11, 2011


S
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K, JV (J.F. Shea


Kiewit, Joint Venture)


NTP by CEG


December 16, 2011


Tunnel to be fully lined (full circumference liner)


Participation goals met 15% (M), 8% (W) & 3% (V)


Planned 90 MGD deep rock pump station at launch site


Awarded price
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$179,323,115 (

savings of $106,744,660) (8 Miles)


Achievement of Full Operations


December 31, 2017 consent decree schedule

Deep Rock Tunnel Connector (DRTC) Project


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TBM Train


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TBM Complexity

Launch Shaft


Reinforced Concrete Ring Beam


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Launch Shaft


“Drill & Shoot” Holes


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Launch Shaft


Microphone and Seismograph Monitoring


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Launch Shaft


Securing the Blasting Cap


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Launch Shaft


“Shot Rock” at Bottom of Shaft


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Launch Shaft


Excavated “Shot Rock” (Shale)


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Looking Down Launch Shaft


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Looking Up Launch Shaft


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Starter Tunnel


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Near Surface Work


Highest Impact, Highest Risk

Near Surface Complexity


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Deep Tunnel Pump Station Rendering


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How Deep is the Deep Tunnel Pump Station?


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Next Steps and Coordination




Project Success


Everybody!


Continuous Coordination


We’re All In this Together


City is Party to the LTCP Consent Decree


Most Near Surface Project are in Street and Parks


Making the Environment Better than when We Started


Improving the City’s Socio
-
Economic Climate


Value Added


Meaningful and Fair Restoration and Improvements


Other Key Projects Ongoing


FC 01


Indiana Avenue and 10
th

Street (April 2013)


WR 06


Bush Stadium Site (April 2013)


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Discussion / Q&A