Location

St. Louis, Missouri

Session Start Date

4-2-1995

Session End Date

4-7-1995

Abstract

The weighted residual method was applied to the problem of scattering and diffraction of plane SH-waves by a shallow alluvial valley of arbitrary shape on the surface of a two-dimensional half-space. The formulation was also applied to the case of a shallow canyon. In order to demonstrate the versatility of the method, it was applied to shallow circular, shallow elliptical, and shallow rectangular canyons and alluvial valleys. Results obtained for the cases of a semi-cylindrical and a shallow semi-elliptical valleys and canyons match those obtained using closed form solutions. It was shown that significant ground motion amplifications, with respect to the amplitude of incident waves, occurred near and in the canyon or valley. Amplifications were dependent upon the shape and depth of the canyon or valley, the relative properties of the alluvium in the valley and the surrounding medium, and the frequency and angle of incidence of incoming waves. Amplification profiles for the lower frequency incident waves were simple near the canyon and valley on the surface of the half-space with peak amplifications that did not significantly vary from 2, the value expected on the surface of the half-space. Within a valley containing softer alluvium, the amplification profile is more complex with values larger than 2. Within the canyon, amplification profiles remained simple with peaks near 2. As the frequency of the incident waves are increased, the amplification profiles near the canyon and valley became more complicated with peak values exceeding 5 for rectangular shaped valleys. Within the canyon, the profiles were similar. On the surface of the valley, the amplification profiles are more complex with peak values exceeding 10 for many valley configurations.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

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

Meeting Name

Third Conference

Publisher

University of Missouri--Rolla

Publication Date

4-2-1995

Document Version

Final Version

Rights

© 1995 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Apr 2nd, 12:00 AM Apr 7th, 12:00 AM

Scattering of SH-Waves by Arbitrary Surface Topography

St. Louis, Missouri

The weighted residual method was applied to the problem of scattering and diffraction of plane SH-waves by a shallow alluvial valley of arbitrary shape on the surface of a two-dimensional half-space. The formulation was also applied to the case of a shallow canyon. In order to demonstrate the versatility of the method, it was applied to shallow circular, shallow elliptical, and shallow rectangular canyons and alluvial valleys. Results obtained for the cases of a semi-cylindrical and a shallow semi-elliptical valleys and canyons match those obtained using closed form solutions. It was shown that significant ground motion amplifications, with respect to the amplitude of incident waves, occurred near and in the canyon or valley. Amplifications were dependent upon the shape and depth of the canyon or valley, the relative properties of the alluvium in the valley and the surrounding medium, and the frequency and angle of incidence of incoming waves. Amplification profiles for the lower frequency incident waves were simple near the canyon and valley on the surface of the half-space with peak amplifications that did not significantly vary from 2, the value expected on the surface of the half-space. Within a valley containing softer alluvium, the amplification profile is more complex with values larger than 2. Within the canyon, amplification profiles remained simple with peaks near 2. As the frequency of the incident waves are increased, the amplification profiles near the canyon and valley became more complicated with peak values exceeding 5 for rectangular shaped valleys. Within the canyon, the profiles were similar. On the surface of the valley, the amplification profiles are more complex with peak values exceeding 10 for many valley configurations.