Location

San Diego, California

Session Start Date

5-24-2010

Session End Date

5-29-2010

Abstract

Wood (1973) provided analytical solutions for the response of a rigid wall retaining elastic uniform soil backfill of finite length subjected to harmonic base excitation. Wu and Finn (1999) proposed a modified shear beam solution and derived closed-form formulations for computing dynamic soil pressures under harmonic loading. However, for rigid walls retaining sloped backfills, analytical solutions are not available for computing seismic soil pressures against the walls. In the current study, seismic soil pressures on rigid walls retaining 2H:1V (27°) sloped backfills have been computed using a total of eight acceleration time histories recorded in past large earthquakes. These records were selected and linearly scaled to three levels of ground motions with a nominal PGA of 0.26g, 0.48g and 0.71g. Nonlinear time-history analyses were conducted using the computer program VERSAT-2D which uses a hyperbolic stress – strain model to simulate the hysteresis response of soil under cyclic loads. Soil pressure diagrams are shown in the paper for horizontal backfills (φ=32°), and for sloped backfills with loose sand (φ=32°) and dense sand (φ=40°) under the three levels of ground motions. A soil pressure coefficient, K0E, has been introduced to represent the total static and seismic pressures on a rigid (or non-yielding) wall. It is found that K0E varies from 1.1, 1.7 to 2.2 for horizontal backfills under ground motions of 0.26g, 0.48g and 0.71g, respectively. K0E increases to 2.7, 3.8 and 4.9 for the 27° sloped backfills under the same three levels of ground motions, respectively. The point of thrust is at about 0.47H above the base of wall for horizontal backfills, but for sloped backfills it increases to 0.53H for loose sand and 0.55H for dense sand.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Meeting Name

Fifth Conference

Publisher

Missouri University of Science and Technology

Publication Date

5-24-2010

Document Version

Final Version

Rights

© 2010 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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May 24th, 12:00 AM May 29th, 12:00 AM

Seismic Soil Pressures on Rigid Walls with Sloped Backfills

San Diego, California

Wood (1973) provided analytical solutions for the response of a rigid wall retaining elastic uniform soil backfill of finite length subjected to harmonic base excitation. Wu and Finn (1999) proposed a modified shear beam solution and derived closed-form formulations for computing dynamic soil pressures under harmonic loading. However, for rigid walls retaining sloped backfills, analytical solutions are not available for computing seismic soil pressures against the walls. In the current study, seismic soil pressures on rigid walls retaining 2H:1V (27°) sloped backfills have been computed using a total of eight acceleration time histories recorded in past large earthquakes. These records were selected and linearly scaled to three levels of ground motions with a nominal PGA of 0.26g, 0.48g and 0.71g. Nonlinear time-history analyses were conducted using the computer program VERSAT-2D which uses a hyperbolic stress – strain model to simulate the hysteresis response of soil under cyclic loads. Soil pressure diagrams are shown in the paper for horizontal backfills (φ=32°), and for sloped backfills with loose sand (φ=32°) and dense sand (φ=40°) under the three levels of ground motions. A soil pressure coefficient, K0E, has been introduced to represent the total static and seismic pressures on a rigid (or non-yielding) wall. It is found that K0E varies from 1.1, 1.7 to 2.2 for horizontal backfills under ground motions of 0.26g, 0.48g and 0.71g, respectively. K0E increases to 2.7, 3.8 and 4.9 for the 27° sloped backfills under the same three levels of ground motions, respectively. The point of thrust is at about 0.47H above the base of wall for horizontal backfills, but for sloped backfills it increases to 0.53H for loose sand and 0.55H for dense sand.