Subsurface Drainage for Landslide and Slope Stabilization

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General Information
Study Number: TPF-5(151)
Lead Organization: Washington State Department of Transportation
Contract Start Date: Jan 01, 2006
Solicitation Number: 1078
Partners: BC Hydro, CA, MDOT SHA, MS, MT, NHDOT, OH, PADOT, TX, WA, WY
Status: Closed
Est. Completion Date: Jun 30, 2013
Contract/Other Number:
Last Updated: May 12, 2014
Contract End Date: Jun 30, 2013
Financial Summary
Contract Amount: $310,000.00
Total Commitments Received: $362,000.00
100% SP&R Approval: Approved
Contact Information
Lead Study Contact(s): Kim Willoughby
willouk@wsdot.wa.gov
Phone: 360-705-7978
FHWA Technical Liaison(s): Michael Adams
mike.adams@dot.gov
Phone: 202-493-3025
Organization Year Commitments Technical Contact Name Funding Contact Name Contact Number Email Address
BC Hydro 2010 $0.00
California Department of Transportation 2007 $10,000.00 Sang Le 916-227-0701 sang.le@dot.ca.gov
California Department of Transportation 2008 $10,000.00 Sang Le 916-227-0701 sang.le@dot.ca.gov
California Department of Transportation 2009 $10,000.00 Sang Le 916-227-0701 sang.le@dot.ca.gov
California Department of Transportation 2010 $10,000.00 Sang Le 916-227-0701 sang.le@dot.ca.gov
Maryland Department of Transportation State Highway Administration 2007 $10,000.00 Allison Hardt 410-545-2916 ahardt@mdot.maryland.gov
Maryland Department of Transportation State Highway Administration 2008 $10,000.00 Allison Hardt 410-545-2916 ahardt@mdot.maryland.gov
Maryland Department of Transportation State Highway Administration 2009 $10,000.00 Allison Hardt 410-545-2916 ahardt@mdot.maryland.gov
Maryland Department of Transportation State Highway Administration 2010 $10,000.00 Allison Hardt 410-545-2916 ahardt@mdot.maryland.gov
Maryland Department of Transportation State Highway Administration 2011 $8,000.00 Allison Hardt 410-545-2916 ahardt@mdot.maryland.gov
Mississippi Department of Transportation 2007 $10,000.00 Sean Ferguson James Watkins 601-359-7650 jwatkins@mdot.state.ms.us
Mississippi Department of Transportation 2008 $10,000.00 Sean Ferguson James Watkins 601-359-7650 jwatkins@mdot.state.ms.us
Mississippi Department of Transportation 2009 $10,000.00 Sean Ferguson James Watkins 601-359-7650 jwatkins@mdot.state.ms.us
Mississippi Department of Transportation 2010 $10,000.00 Sean Ferguson James Watkins 601-359-7650 jwatkins@mdot.state.ms.us
Montana Department of Transportation 2006 $5,000.00 Jeff Jackson Susan Sillick 406-444-7693 ssillick@mt.gov
Montana Department of Transportation 2007 $5,000.00 Jeff Jackson Susan Sillick 406-444-7693 ssillick@mt.gov
Montana Department of Transportation 2008 $5,000.00 Jeff Jackson Susan Sillick 406-444-7693 ssillick@mt.gov
Montana Department of Transportation 2009 $5,000.00 Jeff Jackson Susan Sillick 406-444-7693 ssillick@mt.gov
Montana Department of Transportation 2011 $8,000.00 Jeff Jackson Susan Sillick 406-444-7693 ssillick@mt.gov
New Hampshire Department of Transportation 2007 $15,000.00 Dick Lane Glenn Roberts 603-271-3151 Glenn.Roberts@dot.nh.gov
New Hampshire Department of Transportation 2008 $15,000.00 Dick Lane Glenn Roberts 603-271-3151 Glenn.Roberts@dot.nh.gov
New Hampshire Department of Transportation 2011 $8,000.00 Dick Lane Glenn Roberts 603-271-3151 Glenn.Roberts@dot.nh.gov
Ohio Department of Transportation 2007 $10,000.00 Gene Geiger Jill Martindale 6146448173 jacquelin.martindale@dot.ohio.gov
Ohio Department of Transportation 2008 $10,000.00 Gene Geiger Jill Martindale 6146448173 jacquelin.martindale@dot.ohio.gov
Ohio Department of Transportation 2009 $10,000.00 Gene Geiger Jill Martindale 6146448173 jacquelin.martindale@dot.ohio.gov
Ohio Department of Transportation 2010 $10,000.00 Gene Geiger Jill Martindale 6146448173 jacquelin.martindale@dot.ohio.gov
Ohio Department of Transportation 2011 $10,000.00 Gene Geiger Jill Martindale 6146448173 jacquelin.martindale@dot.ohio.gov
Pennsylvania Department of Transportation 2007 $10,000.00 Kerry Petrasic Lisa Tarson (717) 705-2202 ltarson@pa.gov
Pennsylvania Department of Transportation 2008 $10,000.00 Kerry Petrasic Lisa Tarson (717) 705-2202 ltarson@pa.gov
Texas Department of Transportation 2006 $10,000.00 Marcus Galvan Frank Bailey 512- 416-4730 rtimain@txdot.gov
Texas Department of Transportation 2007 $10,000.00 Marcus Galvan Frank Bailey 512- 416-4730 rtimain@txdot.gov
Texas Department of Transportation 2008 $10,000.00 Marcus Galvan Frank Bailey 512- 416-4730 rtimain@txdot.gov
Texas Department of Transportation 2009 $10,000.00 Marcus Galvan Frank Bailey 512- 416-4730 rtimain@txdot.gov
Texas Department of Transportation 2010 $8,000.00 Marcus Galvan Frank Bailey 512- 416-4730 rtimain@txdot.gov
Washington State Department of Transportation 2006 $10,000.00 Tim Carlile 360-705-7975 carlilt@wsdot.wa.gov
Washington State Department of Transportation 2011 $10,000.00 Tim Carlile 360-705-7975 carlilt@wsdot.wa.gov
Wyoming Department of Transportation 2007 $30,000.00 Mark Falk Michael Patritch 307-777-4182 michael.patritch@dot.state.wy.us

Study Description

In many cases, slope instability can be attributed to the effects of groundwater and associated pore-water pressures. Typically, drainage considerations for embankments can be readily incorporated during the design and construction process. However, subsurface drainage design and installation for marginally stable existing or new cut slopes can be challenging and typically involves the installation of horizontal drains and interceptor trenches. Horizontal drains can function unpredictably if not designed or installed adequately, or sited in inappropriate materials. Subsurface drainage is generally understood to be an important concept; nevertheless, the underlying principles, design, construction and maintenance considerations are not fully realized nor is the state-of-the-practice adequately documented. As a result, subsurface drains are often installed in a makeshift manner with varying degrees of success. Although subsurface drainage and horizontal drains have been used for many years, the amount of applied research directed at improving subsurface drainage techniques for slope stabilization applications is limited.

Research is needed to identify, collect and develop best practices and guidelines to raise the standards for subsurface drainage design, installation and maintenance. This research is especially important because subsurface drainage is typically the most cost-effective stabilization measure, often being an order of magnitude less than other commonly employed slope stabilization measures. In addition, the research should explore new applications of existing materials and technologies that can be advantageously applied to subsurface drainage systems for slope stabilization. Examples could include trenchless technologies as well as other innovative excavation equipment and techniques that could be adapted to provide more effective, efficient installation and function of subsurface drainage systems within marginally stable slopes.

Properly designed, installed and maintained subsurface drainage systems can, in many instances, be the most cost effective solution to stabilize slopes by lowering and controlling groundwater flow. Unfortunately, concerns with the effectiveness and long-term performance of drainage methods have limited the application of such techniques as a primary means to mitigate slope instability. This uncertainty has limited their use even when subsurface information and stability analyses clearly indicate that stabilization could be achieved with proper modification and control of groundwater conditions. The research and development proposed herein will potentially advance more extensive use of subsurface drainage systems for slope stabilization, significantly reduce expenditures for slope stabilization, improve performance, and provide for more rapid installation.

Objectives

The objectives of this research are as follows:

- To provide best practices and guidance for subsurface drainage applications for slope stabilization, including subsurface investigation and testing, groundwater-flow characterization, analysis, drain configurations and design, installation methods, monitoring, and maintenance.

- To evaluate new applications of existing materials and technologies, such as trenchless technologies (horizontal directional drilling, micro tunneling, guided boring, etc.) and other innovative technologies and materials, for stabilizing slopes using subsurface drainage.

Scope of Work

The anticipated scope of the study would consist of the following tasks:

- Perform a literature review of applications, design methodology, construction, and maintenance of subsurface drainage systems used for slope stabilization;

- Survey an appropriate range of designers/owners regarding applications, types of systems, design methodologies, and function/performance;

- Evaluate short- and long-term performance of a limited number of existing installations utilizing available or new instrumentation;

- With currently available groundwater characterization and modeling techniques, develop methodology for determining appropriate applications and design of subsurface drainage for slope stabilization;

- Produce a summary report that includes detailed recommendations/guidelines on site suitability; groundwater characterization; design methodology; detailing and generalized specifications; construction; and maintenance of subsurface drainage systems.

A technical advisory group consisting of representatives from contributing agencies and invited participants will refine this scope of work and provide periodic technical input/guidance throughout the duration of the research.

Documents Attached
Title File/Link Type Privacy Download
Final Report http://www.wsdot.wa.gov/research/reports/fullreports/787.1.pdf Final Report Public
Final Report http://www.wsdot.wa.gov/research/reports/fullreports/787.1.pdf Final Report Public
Acceptance memo TPF-5_151_Memo.pdf Memorandum Public
Official Closeout Memo TPF-5(151) -- Close out Memo - Electronic Signature.pdf Memorandum Public
Financial Spreadsheet TPF 5-(151) Expenses Allocation spreadsheet.pdf Other Public
Quarterly Report: January 1, 2007 - March 31, 2007 Qtr_Rep2007-03-31.pdf Quarterly Progress Report Public
Quarterly Report: April 1, 2007 - June 30, 2007 Qtr_Rep2007-06-30.pdf Quarterly Progress Report Public
Quarterly Report: July 1, 2007 - September 30, 2007 Qtr_Rep2007-09-30.pdf Quarterly Progress Report Public
Quarterly Report: January 1, 2008 - March 31, 2008 Qtr_Rep2008-03-31.pdf Quarterly Progress Report Public
Quarterly Report: April 1, 2008 - June 30, 2008 Qtr_Rep2008-06-30.pdf Quarterly Progress Report Public
Quarterly Report: October 1, 2008 - December 31, 2008 Qtr_Rep2008-12-31.pdf Quarterly Progress Report Public
Quarterly Report: January 1, 2009 - March 31, 2009 Qtr_Rep2009-03-31.pdf Quarterly Progress Report Public
Quarterly Report: July 1, 2009 - September 30, 2009 Qtr_Rep2009-09-30.pdf Quarterly Progress Report Public
Quarterly Report: October 1, 2009 - December 31, 2009 Qtr_Rep2009-12-31.pdf Quarterly Progress Report Public
Quarterly Report: January 1, 2010 - March 31, 2010 TPF-5(151)_1st_Quarter_2010.pdf Quarterly Progress Report Public
Quarterly Report: April 1, 2010 - June 30, 2010 TPF-5(151)_2nd_Quarter_2010.pdf Quarterly Progress Report Public
Quarterly Report: January 1, 2011 - March 31, 2011 TPF-5(151)_1st_Quarter_2011.pdf Quarterly Progress Report Public
Quarterly Report: April 1, 2011 - June 30, 2011 TPF-5(151)_2nd_Quarter_2011.pdf Quarterly Progress Report Public
Quarterly Report: July 1 - September 30, 2011 TPF-5(151) 3rd Quarter 2011.doc Quarterly Progress Report Public
10/1/11-12/31/11 TPF-5(151) 4th Quarter 2011.docx Quarterly Progress Report Public
1/1/12-3/31/12 TPF-5(151) 1st Quarter 2012.docx Quarterly Progress Report Public
4/1/12-6/30/12 TPF-5(151) 2nd Quarter 2012.docx Quarterly Progress Report Public
7/1/12-9/30/12 TPF-5(151) 3rd Quarter 2012.docx Quarterly Progress Report Public
10/1/12-12/31/12 TPF-5(151) 4th Quarter 2012.docx Quarterly Progress Report Public
4/1/13-6/30/13 TPF-5(151) 2nd Quarter 2013.docx Quarterly Progress Report Public

Subsurface Drainage for Landslide and Slope Stabilization

General Information
Study Number: TPF-5(151)
Lead Organization: Washington State Department of Transportation
Contract Start Date: Jan 01, 2006
Solicitation Number: 1078
Partners: BC Hydro, CA, MDOT SHA, MS, MT, NHDOT, OH, PADOT, TX, WA, WY
Status: Closed
Est. Completion Date: Jun 30, 2013
Contract/Other Number:
Last Updated: May 12, 2014
Contract End Date: Jun 30, 2013
Financial Summary
Contract Amount: $310,000.00
Total Commitments Received: $362,000.00
100% SP&R Approval:
Contact Information
Lead Study Contact(s): Kim Willoughby
willouk@wsdot.wa.gov
Phone: 360-705-7978
FHWA Technical Liaison(s): Michael Adams
mike.adams@dot.gov
Phone: 202-493-3025
Commitments by Organizations
Organization Year Commitments Technical Contact Name Funding Contact Name Contact Number Email Address
BC Hydro 2010 $0.00
California Department of Transportation 2007 $10,000.00 Sang Le 916-227-0701 sang.le@dot.ca.gov
California Department of Transportation 2008 $10,000.00 Sang Le 916-227-0701 sang.le@dot.ca.gov
California Department of Transportation 2009 $10,000.00 Sang Le 916-227-0701 sang.le@dot.ca.gov
California Department of Transportation 2010 $10,000.00 Sang Le 916-227-0701 sang.le@dot.ca.gov
Maryland Department of Transportation State Highway Administration 2007 $10,000.00 Allison Hardt 410-545-2916 ahardt@mdot.maryland.gov
Maryland Department of Transportation State Highway Administration 2008 $10,000.00 Allison Hardt 410-545-2916 ahardt@mdot.maryland.gov
Maryland Department of Transportation State Highway Administration 2009 $10,000.00 Allison Hardt 410-545-2916 ahardt@mdot.maryland.gov
Maryland Department of Transportation State Highway Administration 2010 $10,000.00 Allison Hardt 410-545-2916 ahardt@mdot.maryland.gov
Maryland Department of Transportation State Highway Administration 2011 $8,000.00 Allison Hardt 410-545-2916 ahardt@mdot.maryland.gov
Mississippi Department of Transportation 2007 $10,000.00 Sean Ferguson James Watkins 601-359-7650 jwatkins@mdot.state.ms.us
Mississippi Department of Transportation 2008 $10,000.00 Sean Ferguson James Watkins 601-359-7650 jwatkins@mdot.state.ms.us
Mississippi Department of Transportation 2009 $10,000.00 Sean Ferguson James Watkins 601-359-7650 jwatkins@mdot.state.ms.us
Mississippi Department of Transportation 2010 $10,000.00 Sean Ferguson James Watkins 601-359-7650 jwatkins@mdot.state.ms.us
Montana Department of Transportation 2006 $5,000.00 Jeff Jackson Susan Sillick 406-444-7693 ssillick@mt.gov
Montana Department of Transportation 2007 $5,000.00 Jeff Jackson Susan Sillick 406-444-7693 ssillick@mt.gov
Montana Department of Transportation 2008 $5,000.00 Jeff Jackson Susan Sillick 406-444-7693 ssillick@mt.gov
Montana Department of Transportation 2009 $5,000.00 Jeff Jackson Susan Sillick 406-444-7693 ssillick@mt.gov
Montana Department of Transportation 2011 $8,000.00 Jeff Jackson Susan Sillick 406-444-7693 ssillick@mt.gov
New Hampshire Department of Transportation 2007 $15,000.00 Dick Lane Glenn Roberts 603-271-3151 Glenn.Roberts@dot.nh.gov
New Hampshire Department of Transportation 2008 $15,000.00 Dick Lane Glenn Roberts 603-271-3151 Glenn.Roberts@dot.nh.gov
New Hampshire Department of Transportation 2011 $8,000.00 Dick Lane Glenn Roberts 603-271-3151 Glenn.Roberts@dot.nh.gov
Ohio Department of Transportation 2007 $10,000.00 Gene Geiger Jill Martindale 6146448173 jacquelin.martindale@dot.ohio.gov
Ohio Department of Transportation 2008 $10,000.00 Gene Geiger Jill Martindale 6146448173 jacquelin.martindale@dot.ohio.gov
Ohio Department of Transportation 2009 $10,000.00 Gene Geiger Jill Martindale 6146448173 jacquelin.martindale@dot.ohio.gov
Ohio Department of Transportation 2010 $10,000.00 Gene Geiger Jill Martindale 6146448173 jacquelin.martindale@dot.ohio.gov
Ohio Department of Transportation 2011 $10,000.00 Gene Geiger Jill Martindale 6146448173 jacquelin.martindale@dot.ohio.gov
Pennsylvania Department of Transportation 2007 $10,000.00 Kerry Petrasic Lisa Tarson (717) 705-2202 ltarson@pa.gov
Pennsylvania Department of Transportation 2008 $10,000.00 Kerry Petrasic Lisa Tarson (717) 705-2202 ltarson@pa.gov
Texas Department of Transportation 2006 $10,000.00 Marcus Galvan Frank Bailey 512- 416-4730 rtimain@txdot.gov
Texas Department of Transportation 2007 $10,000.00 Marcus Galvan Frank Bailey 512- 416-4730 rtimain@txdot.gov
Texas Department of Transportation 2008 $10,000.00 Marcus Galvan Frank Bailey 512- 416-4730 rtimain@txdot.gov
Texas Department of Transportation 2009 $10,000.00 Marcus Galvan Frank Bailey 512- 416-4730 rtimain@txdot.gov
Texas Department of Transportation 2010 $8,000.00 Marcus Galvan Frank Bailey 512- 416-4730 rtimain@txdot.gov
Washington State Department of Transportation 2006 $10,000.00 Tim Carlile 360-705-7975 carlilt@wsdot.wa.gov
Washington State Department of Transportation 2011 $10,000.00 Tim Carlile 360-705-7975 carlilt@wsdot.wa.gov
Wyoming Department of Transportation 2007 $30,000.00 Mark Falk Michael Patritch 307-777-4182 michael.patritch@dot.state.wy.us

Study Description

Study Description

In many cases, slope instability can be attributed to the effects of groundwater and associated pore-water pressures. Typically, drainage considerations for embankments can be readily incorporated during the design and construction process. However, subsurface drainage design and installation for marginally stable existing or new cut slopes can be challenging and typically involves the installation of horizontal drains and interceptor trenches. Horizontal drains can function unpredictably if not designed or installed adequately, or sited in inappropriate materials. Subsurface drainage is generally understood to be an important concept; nevertheless, the underlying principles, design, construction and maintenance considerations are not fully realized nor is the state-of-the-practice adequately documented. As a result, subsurface drains are often installed in a makeshift manner with varying degrees of success. Although subsurface drainage and horizontal drains have been used for many years, the amount of applied research directed at improving subsurface drainage techniques for slope stabilization applications is limited.

Research is needed to identify, collect and develop best practices and guidelines to raise the standards for subsurface drainage design, installation and maintenance. This research is especially important because subsurface drainage is typically the most cost-effective stabilization measure, often being an order of magnitude less than other commonly employed slope stabilization measures. In addition, the research should explore new applications of existing materials and technologies that can be advantageously applied to subsurface drainage systems for slope stabilization. Examples could include trenchless technologies as well as other innovative excavation equipment and techniques that could be adapted to provide more effective, efficient installation and function of subsurface drainage systems within marginally stable slopes.

Properly designed, installed and maintained subsurface drainage systems can, in many instances, be the most cost effective solution to stabilize slopes by lowering and controlling groundwater flow. Unfortunately, concerns with the effectiveness and long-term performance of drainage methods have limited the application of such techniques as a primary means to mitigate slope instability. This uncertainty has limited their use even when subsurface information and stability analyses clearly indicate that stabilization could be achieved with proper modification and control of groundwater conditions. The research and development proposed herein will potentially advance more extensive use of subsurface drainage systems for slope stabilization, significantly reduce expenditures for slope stabilization, improve performance, and provide for more rapid installation.

Objectives

The objectives of this research are as follows:

- To provide best practices and guidance for subsurface drainage applications for slope stabilization, including subsurface investigation and testing, groundwater-flow characterization, analysis, drain configurations and design, installation methods, monitoring, and maintenance.

- To evaluate new applications of existing materials and technologies, such as trenchless technologies (horizontal directional drilling, micro tunneling, guided boring, etc.) and other innovative technologies and materials, for stabilizing slopes using subsurface drainage.

Scope of Work

The anticipated scope of the study would consist of the following tasks:

- Perform a literature review of applications, design methodology, construction, and maintenance of subsurface drainage systems used for slope stabilization;

- Survey an appropriate range of designers/owners regarding applications, types of systems, design methodologies, and function/performance;

- Evaluate short- and long-term performance of a limited number of existing installations utilizing available or new instrumentation;

- With currently available groundwater characterization and modeling techniques, develop methodology for determining appropriate applications and design of subsurface drainage for slope stabilization;

- Produce a summary report that includes detailed recommendations/guidelines on site suitability; groundwater characterization; design methodology; detailing and generalized specifications; construction; and maintenance of subsurface drainage systems.

A technical advisory group consisting of representatives from contributing agencies and invited participants will refine this scope of work and provide periodic technical input/guidance throughout the duration of the research.

Title File/Link Type Private
Final Report Final Report Public
Final Report Final Report Public
Acceptance memo TPF-5_151_Memo.pdf Memorandum Public
Official Closeout Memo TPF-5(151) -- Close out Memo - Electronic Signature.pdf Memorandum Public
Financial Spreadsheet TPF 5-(151) Expenses Allocation spreadsheet.pdf Other Public
Quarterly Report: January 1, 2007 - March 31, 2007 Qtr_Rep2007-03-31.pdf Quarterly Progress Report Public
Quarterly Report: April 1, 2007 - June 30, 2007 Qtr_Rep2007-06-30.pdf Quarterly Progress Report Public
Quarterly Report: July 1, 2007 - September 30, 2007 Qtr_Rep2007-09-30.pdf Quarterly Progress Report Public
Quarterly Report: January 1, 2008 - March 31, 2008 Qtr_Rep2008-03-31.pdf Quarterly Progress Report Public
Quarterly Report: April 1, 2008 - June 30, 2008 Qtr_Rep2008-06-30.pdf Quarterly Progress Report Public
Quarterly Report: October 1, 2008 - December 31, 2008 Qtr_Rep2008-12-31.pdf Quarterly Progress Report Public
Quarterly Report: January 1, 2009 - March 31, 2009 Qtr_Rep2009-03-31.pdf Quarterly Progress Report Public
Quarterly Report: July 1, 2009 - September 30, 2009 Qtr_Rep2009-09-30.pdf Quarterly Progress Report Public
Quarterly Report: October 1, 2009 - December 31, 2009 Qtr_Rep2009-12-31.pdf Quarterly Progress Report Public
Quarterly Report: January 1, 2010 - March 31, 2010 TPF-5(151)_1st_Quarter_2010.pdf Quarterly Progress Report Public
Quarterly Report: April 1, 2010 - June 30, 2010 TPF-5(151)_2nd_Quarter_2010.pdf Quarterly Progress Report Public
Quarterly Report: January 1, 2011 - March 31, 2011 TPF-5(151)_1st_Quarter_2011.pdf Quarterly Progress Report Public
Quarterly Report: April 1, 2011 - June 30, 2011 TPF-5(151)_2nd_Quarter_2011.pdf Quarterly Progress Report Public
Quarterly Report: July 1 - September 30, 2011 TPF-5(151) 3rd Quarter 2011.doc Quarterly Progress Report Public
10/1/11-12/31/11 TPF-5(151) 4th Quarter 2011.docx Quarterly Progress Report Public
1/1/12-3/31/12 TPF-5(151) 1st Quarter 2012.docx Quarterly Progress Report Public
4/1/12-6/30/12 TPF-5(151) 2nd Quarter 2012.docx Quarterly Progress Report Public
7/1/12-9/30/12 TPF-5(151) 3rd Quarter 2012.docx Quarterly Progress Report Public
10/1/12-12/31/12 TPF-5(151) 4th Quarter 2012.docx Quarterly Progress Report Public
4/1/13-6/30/13 TPF-5(151) 2nd Quarter 2013.docx Quarterly Progress Report Public

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