Consequences-Based Analysis of Undrained Shear Behavior of Soils and Liquefaction Hazards, Phase 1: Filling the Data Gaps

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General Information
Study Number: TPF-5(485)
Lead Organization: Utah Department of Transportation
Solicitation Number: 1529
Partners: AK, CA, MO, MS, SC, UT, WA
Status: Cleared by FHWA
Est. Completion Date:
Contract/Other Number:
Last Updated: Oct 14, 2021
Contract End Date:
Financial Summary
Contract Amount:
Total Commitments Received: $420,000.00
100% SP&R Approval: Approved
Contact Information
Lead Study Contact(s): David Stevens
davidstevens@utah.gov
Phone: 801-589-8340
FHWA Technical Liaison(s): Jennifer Nicks
jennifer.nicks@dot.gov
Phone: 202- 493-3075
Organization Year Commitments Technical Contact Name Funding Contact Name Contact Number Email Address
Alaska Department of Transportation and Public Facilities 2021 $20,000.00 Dave Hemstreet Anna Bosin (907)269-6208 anna.bosin@alaska.gov
Alaska Department of Transportation and Public Facilities 2022 $20,000.00 Dave Hemstreet Anna Bosin (907)269-6208 anna.bosin@alaska.gov
Alaska Department of Transportation and Public Facilities 2023 $20,000.00 Dave Hemstreet Anna Bosin (907)269-6208 anna.bosin@alaska.gov
California Department of Transportation 2021 $0.00 AnhDan Le Sang Le 916-227-0701 sang.le@dot.ca.gov
California Department of Transportation 2022 $30,000.00 AnhDan Le Sang Le 916-227-0701 sang.le@dot.ca.gov
California Department of Transportation 2023 $30,000.00 AnhDan Le Sang Le 916-227-0701 sang.le@dot.ca.gov
Mississippi Department of Transportation 2021 $60,000.00 Mike Stroud Robert Vance RVance@mdot.ms.gov
Missouri Department of Transportation 2021 $0.00 Lydia Brownell Jennifer Harper 573-526-3636 Jennifer.Harper@modot.mo.gov
Missouri Department of Transportation 2022 $20,000.00 Lydia Brownell Jennifer Harper 573-526-3636 Jennifer.Harper@modot.mo.gov
Missouri Department of Transportation 2023 $20,000.00 Lydia Brownell Jennifer Harper 573-526-3636 Jennifer.Harper@modot.mo.gov
Missouri Department of Transportation 2024 $20,000.00 Lydia Brownell Jennifer Harper 573-526-3636 Jennifer.Harper@modot.mo.gov
South Carolina Department of Transportation 2021 $20,000.00 Nicholas Harman Terry Swygert 803-737-6691 SwygertTL@scdot.org
South Carolina Department of Transportation 2022 $20,000.00 Nicholas Harman Terry Swygert 803-737-6691 SwygertTL@scdot.org
South Carolina Department of Transportation 2023 $20,000.00 Nicholas Harman Terry Swygert 803-737-6691 SwygertTL@scdot.org
Utah Department of Transportation 2021 $60,000.00 Grant Gummow David Stevens 801-589-8340 davidstevens@utah.gov
Washington State Department of Transportation 2021 $20,000.00 Tony Allen Mustafa Mohamedali 360-704-6307 MOHAMEM@wsdot.wa.gov
Washington State Department of Transportation 2022 $20,000.00 Tony Allen Mustafa Mohamedali 360-704-6307 MOHAMEM@wsdot.wa.gov
Washington State Department of Transportation 2023 $20,000.00 Tony Allen Mustafa Mohamedali 360-704-6307 MOHAMEM@wsdot.wa.gov

Study Description

Soils experience reductions in shear strength when pore pressures increase, which can happen under different types of loadings such as static loadings or earthquake-induced cyclic loadings. At present, widely used correlations for soil strength loss have inconsistencies, especially as it relates to some soil types and their amounts of soil strength loss and associated strains. For example, since the early 1970s, geotechnical engineers worldwide have largely relied upon empirical correlations to predict soil liquefaction susceptibility, triggering, and consequences/damage due to earthquakes. Such analyses are necessary to ensure the stability and adequate performance of structures like buildings, bridges, retaining walls, and engineered soil slopes in the event of an earthquake. While the geotechnical community largely has accepted these empirical correlations as the state of practice, numerous inconsistencies exist in their application. Existing correlations have primarily been developed for clean quartz and silica sands. The application of these correlations and approaches to other soils, including silty soils, gravel-rich soils, sands with variable mineralogy, and even low-plasticity silts and clays is largely unknown. These knowledge gaps contribute to our inability to accurately predict the dynamic behavior of these soils, resulting in empirical correlations to assess liquefaction susceptibility, triggering, and consequences that are inconsistent and result in significantly different remediation designs. Recent cyclic (and even monotonic/static) laboratory testing of various transitional soils validate these concerns. Importantly, these inconsistencies can result in both overly-conservative (expensive) and under-conservative (dangerous) outcomes, neither of which is optimal. To improve the accuracy of static and dynamic soil behavior predictions, there is a need for a universal, consequences-based approach for all soils that focuses on the compressibility and undrained shear behavior of the soil. This may include use of the “delta Q” approach, which is less affected by the overconsolidation ratio and stress history of soil, for improved soil identification and characterization using cone penetration test (CPT) data (Saye et al. 2017, ASCE JGGE), as well as other recent advances in geophysics.

Objectives

The overall objective of this multi-year, multi-phase effort is to create a true performance-based model to evaluate the consequences of undrained response in all soils, including consequences resulting from earthquake-induced liquefaction and cyclic softening. Through this overall project, a more robust method for estimating field performance of soils during undrained events (including earthquakes) will be developed and tested. Due to the ability of the CPT to collect nearly continuous profiles of data in most soil types, for these studies we will focus initially on using CPT data for analyzing undrained shear behavior and liquefaction hazards. The framework is intended to be adaptable to other methods such as Standard Penetration Test (SPT), laboratory testing and analysis, and shear wave velocity (Vs) data.

The objective of this Phase 1 study is to fill critical data gaps to document the undrained shear behavior of sands, silts, and clays for both static and dynamic loadings, and to provide a preliminary set of predictive models for the undrained shear response of soils. We anticipate that several state DOTs would be interested in participating in this initial pooled fund study.

Later, in separate pooled fund studies, Phase 2 would focus on additional development of the models for consequences-based analysis of the undrained shear behavior of soils, and Phase 3 would focus on testing and validation of the models.

Scope of Work

Planned tasks for this Phase 1 study are as follows:

(1) Perform a literature review of related studies.

(2) Conduct a field sampling program for transitional soils at sites in several states.

(3) Perform conventional laboratory tests.

(4) Perform advanced laboratory tests.

(5) Compile a database of soil in-situ resistance and corresponding undrained shear strength and strains from across the United States.

(6) As part of the Next Generation Liquefaction (NGL) Project modeling effort, develop and deliver a preliminary set of predictive models based on available field-case-history data for the monotonic and cyclic undrained shear response of soils. In addition to liquefaction triggering, these models may include excess pore pressure ratio, maximum shear strain, volumetric strain, lateral deformations, and degraded undrained shear strength.

(7) Prepare the Phase 1 Final Report.

(8) Meet with the multi-state study panel to discuss results, including whether further research is recommended, and what it might entail.

(9) Conduct education, outreach, and training.

Comments

Additional agencies are welcome to join this TPF study while it is going. Please contact David Stevens (davidstevens@utah.gov) if you are interested in having your agency join the study.  The Utah Department of Transportation (UDOT) will be the lead agency for this Phase 1 study, with Grant Gummow (ggummow@utah.gov) as the UDOT Champion. We intend to hire a firm or university as the prime consultant through qualifications-based selection in the UDOT General Engineering Services Pool, Research Work Discipline, after sufficient funds are committed by study partner agencies.

The Phase 1 study is planned to begin in summer of 2021 or 2022, with study completion in approximately three years’ time.

The minimum partner commitment expected for the Phase 1 study is $60,000 in FFY 2021 or 2022, or the $60,000 total can be split between FFY 2021, 2022, and 2023 (or 2024) at a portion per year.

Subjects: Bridges, Other Structures, and Hydraulics and Hydrology Soils, Geology, and Foundations

Documents Attached
Title File/Link Type Privacy Download
Acceptance Memo TPF-5(485) Acceptance memo TPF5485 signed.pdf Memorandum Public

Consequences-Based Analysis of Undrained Shear Behavior of Soils and Liquefaction Hazards, Phase 1: Filling the Data Gaps

General Information
Study Number: TPF-5(485)
Lead Organization: Utah Department of Transportation
Solicitation Number: 1529
Partners: AK, CA, MO, MS, SC, UT, WA
Status: Cleared by FHWA
Est. Completion Date:
Contract/Other Number:
Last Updated: Oct 14, 2021
Contract End Date:
Financial Summary
Contract Amount:
Total Commitments Received: $420,000.00
100% SP&R Approval:
Contact Information
Lead Study Contact(s): David Stevens
davidstevens@utah.gov
Phone: 801-589-8340
FHWA Technical Liaison(s): Jennifer Nicks
jennifer.nicks@dot.gov
Phone: 202- 493-3075
Commitments by Organizations
Organization Year Commitments Technical Contact Name Funding Contact Name Contact Number Email Address
Alaska Department of Transportation and Public Facilities 2021 $20,000.00 Dave Hemstreet Anna Bosin (907)269-6208 anna.bosin@alaska.gov
Alaska Department of Transportation and Public Facilities 2022 $20,000.00 Dave Hemstreet Anna Bosin (907)269-6208 anna.bosin@alaska.gov
Alaska Department of Transportation and Public Facilities 2023 $20,000.00 Dave Hemstreet Anna Bosin (907)269-6208 anna.bosin@alaska.gov
California Department of Transportation 2021 $0.00 AnhDan Le Sang Le 916-227-0701 sang.le@dot.ca.gov
California Department of Transportation 2022 $30,000.00 AnhDan Le Sang Le 916-227-0701 sang.le@dot.ca.gov
California Department of Transportation 2023 $30,000.00 AnhDan Le Sang Le 916-227-0701 sang.le@dot.ca.gov
Mississippi Department of Transportation 2021 $60,000.00 Mike Stroud Robert Vance RVance@mdot.ms.gov
Missouri Department of Transportation 2021 $0.00 Lydia Brownell Jennifer Harper 573-526-3636 Jennifer.Harper@modot.mo.gov
Missouri Department of Transportation 2022 $20,000.00 Lydia Brownell Jennifer Harper 573-526-3636 Jennifer.Harper@modot.mo.gov
Missouri Department of Transportation 2023 $20,000.00 Lydia Brownell Jennifer Harper 573-526-3636 Jennifer.Harper@modot.mo.gov
Missouri Department of Transportation 2024 $20,000.00 Lydia Brownell Jennifer Harper 573-526-3636 Jennifer.Harper@modot.mo.gov
South Carolina Department of Transportation 2021 $20,000.00 Nicholas Harman Terry Swygert 803-737-6691 SwygertTL@scdot.org
South Carolina Department of Transportation 2022 $20,000.00 Nicholas Harman Terry Swygert 803-737-6691 SwygertTL@scdot.org
South Carolina Department of Transportation 2023 $20,000.00 Nicholas Harman Terry Swygert 803-737-6691 SwygertTL@scdot.org
Utah Department of Transportation 2021 $60,000.00 Grant Gummow David Stevens 801-589-8340 davidstevens@utah.gov
Washington State Department of Transportation 2021 $20,000.00 Tony Allen Mustafa Mohamedali 360-704-6307 MOHAMEM@wsdot.wa.gov
Washington State Department of Transportation 2022 $20,000.00 Tony Allen Mustafa Mohamedali 360-704-6307 MOHAMEM@wsdot.wa.gov
Washington State Department of Transportation 2023 $20,000.00 Tony Allen Mustafa Mohamedali 360-704-6307 MOHAMEM@wsdot.wa.gov

Study Description

Study Description

Soils experience reductions in shear strength when pore pressures increase, which can happen under different types of loadings such as static loadings or earthquake-induced cyclic loadings. At present, widely used correlations for soil strength loss have inconsistencies, especially as it relates to some soil types and their amounts of soil strength loss and associated strains. For example, since the early 1970s, geotechnical engineers worldwide have largely relied upon empirical correlations to predict soil liquefaction susceptibility, triggering, and consequences/damage due to earthquakes. Such analyses are necessary to ensure the stability and adequate performance of structures like buildings, bridges, retaining walls, and engineered soil slopes in the event of an earthquake. While the geotechnical community largely has accepted these empirical correlations as the state of practice, numerous inconsistencies exist in their application. Existing correlations have primarily been developed for clean quartz and silica sands. The application of these correlations and approaches to other soils, including silty soils, gravel-rich soils, sands with variable mineralogy, and even low-plasticity silts and clays is largely unknown. These knowledge gaps contribute to our inability to accurately predict the dynamic behavior of these soils, resulting in empirical correlations to assess liquefaction susceptibility, triggering, and consequences that are inconsistent and result in significantly different remediation designs. Recent cyclic (and even monotonic/static) laboratory testing of various transitional soils validate these concerns. Importantly, these inconsistencies can result in both overly-conservative (expensive) and under-conservative (dangerous) outcomes, neither of which is optimal. To improve the accuracy of static and dynamic soil behavior predictions, there is a need for a universal, consequences-based approach for all soils that focuses on the compressibility and undrained shear behavior of the soil. This may include use of the “delta Q” approach, which is less affected by the overconsolidation ratio and stress history of soil, for improved soil identification and characterization using cone penetration test (CPT) data (Saye et al. 2017, ASCE JGGE), as well as other recent advances in geophysics.

Objectives

The overall objective of this multi-year, multi-phase effort is to create a true performance-based model to evaluate the consequences of undrained response in all soils, including consequences resulting from earthquake-induced liquefaction and cyclic softening. Through this overall project, a more robust method for estimating field performance of soils during undrained events (including earthquakes) will be developed and tested. Due to the ability of the CPT to collect nearly continuous profiles of data in most soil types, for these studies we will focus initially on using CPT data for analyzing undrained shear behavior and liquefaction hazards. The framework is intended to be adaptable to other methods such as Standard Penetration Test (SPT), laboratory testing and analysis, and shear wave velocity (Vs) data.

The objective of this Phase 1 study is to fill critical data gaps to document the undrained shear behavior of sands, silts, and clays for both static and dynamic loadings, and to provide a preliminary set of predictive models for the undrained shear response of soils. We anticipate that several state DOTs would be interested in participating in this initial pooled fund study.

Later, in separate pooled fund studies, Phase 2 would focus on additional development of the models for consequences-based analysis of the undrained shear behavior of soils, and Phase 3 would focus on testing and validation of the models.

Scope of Work

Planned tasks for this Phase 1 study are as follows:

(1) Perform a literature review of related studies.

(2) Conduct a field sampling program for transitional soils at sites in several states.

(3) Perform conventional laboratory tests.

(4) Perform advanced laboratory tests.

(5) Compile a database of soil in-situ resistance and corresponding undrained shear strength and strains from across the United States.

(6) As part of the Next Generation Liquefaction (NGL) Project modeling effort, develop and deliver a preliminary set of predictive models based on available field-case-history data for the monotonic and cyclic undrained shear response of soils. In addition to liquefaction triggering, these models may include excess pore pressure ratio, maximum shear strain, volumetric strain, lateral deformations, and degraded undrained shear strength.

(7) Prepare the Phase 1 Final Report.

(8) Meet with the multi-state study panel to discuss results, including whether further research is recommended, and what it might entail.

(9) Conduct education, outreach, and training.

Comments

Additional agencies are welcome to join this TPF study while it is going. Please contact David Stevens (davidstevens@utah.gov) if you are interested in having your agency join the study.  The Utah Department of Transportation (UDOT) will be the lead agency for this Phase 1 study, with Grant Gummow (ggummow@utah.gov) as the UDOT Champion. We intend to hire a firm or university as the prime consultant through qualifications-based selection in the UDOT General Engineering Services Pool, Research Work Discipline, after sufficient funds are committed by study partner agencies.

The Phase 1 study is planned to begin in summer of 2021 or 2022, with study completion in approximately three years’ time.

The minimum partner commitment expected for the Phase 1 study is $60,000 in FFY 2021 or 2022, or the $60,000 total can be split between FFY 2021, 2022, and 2023 (or 2024) at a portion per year.

Subjects: Bridges, Other Structures, and Hydraulics and Hydrology Soils, Geology, and Foundations

Title File/Link Type Private
Acceptance Memo TPF-5(485) Acceptance memo TPF5485 signed.pdf Memorandum Public

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