Seismic Earth Pressure Variations in Retaining Walls with Cohesive Backfill Material

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ASCE G-I Case History Night, April 28, 2016

Seismic Earth Pressure Variations in Retaining Walls with Cohesive Backfill Material

Siavash Zamiran, Abdolreza OsouliCivil Engineering Department

April 28, 2016

OutlineConducting numerical models to evaluate seismic earth pressureUsing finite difference method, FLAC softwareAssuming soil cohesion for backfill Assuming soil-wall adhesionConsidering different earthquake loadingConsidering hysteretic behavior of soil Calibrating of the model with centrifuge tests conducted by Agusti and Sitar, 20132

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Caused by Kobe Earthquake in 1995Failures of Retaining Walls Due to Earthquake

Failures of Retaining Walls Due to Earthquake Loading4

Caused by Mid-Niigata Prefecture Earthquake in 2004

Seismic hazard map of the USA5

Reference: United States Geological Survey

New Madrid seismic zone6

Reference: United States Geological Survey

Analytical methods7

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Some of the analytical methods which consider backfill cohesion

Centrifuge Model9Based on study by Agusti and Sitar, 2013Seismic earth pressure on retaining structures in cohesive soilsUC Berkeley Sponsored by California Department of Transportation

Numerical Modeling Geometry10

Soil Properties11

Constitutive model: UBCHYSTSoil type: low plasticity lean clay (CL), called Yolo Loam from a borrow pit at the centrifuge facilityDensity= 2038.7 kg/m3

Interaction of Wall and Soil12

Computer simulation of retaining wall13

ACCELERATION AND DISPLACEMENT HISTORY14

KobeKocaeli

Seismic earth pressure coefficient versus free field acceleration15

Study phases in progress16Effect of strength properties: cohesion and friction angleEffect of different earthquakesEffect of earthquake intensitiesEffect of wall rigidityEffect of soil-wall interactionEffect of backfill saturation

Analyzing the responses 17Seismic earth pressure approachAnalytical: Mononobe-Okabe, Shukla, etc, DOTs

Displacement approachAnalytical: Newmark method, AASHTO

Fragility analysis18Based on methodology developed by Argyroudis et. al, NIT, (2013)Development of fragility functions for geotechnical constructions: Application to cantilever retaining walls

Workshops held in SIUE:Introduction to Computational Geotechnics, Jan 2016Numerical Modeling of Foundations Using FLAC3D, Jan 2015Underground Coal Mine Stability Analysis, Jan 2015Numerical Modeling in Geotechnical Engineering 2, Oct 2014Numerical Modeling in Geotechnical Engineering 1, Aug 201419

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Introduction to Computational Geotechnics, Jan 2016

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Numerical Modeling in Geotechnical Engineering, Oct 2014

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Thank you. Questions?

References23Agusti, G. C., & Sitar, N. (2013). Seismic Earth Pressures on Retaining Structures in Cohesive Soils (No. UCB GT 13-02). California Department of Transportation.

Argyroudis, S., Kaynia, A. M., & Pitilakis, K. (2013). Development of fragility functions for geotechnical constructions: Application to cantilever retaining walls. Soil Dynamics and Earthquake Engineering, 50, 106116.

Shukla, S. K., Gupta, S. K., & Sivakugan, N. (2009). Active Earth Pressure on Retaining Wall for c- Soil Backfill under Seismic Loading Condition. Journal of Geotechnical and Geoenvironmental Engineering, 135(5), 690696.

Mononobe, N., & Matsuo, H. (1929). On the Determination of Earth Pressures During Earthquakes. In World Engineering Congress 9 (pp. 177185).

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