Location

St. Louis, Missouri

Session Start Date

3-11-1991

Session End Date

3-15-1991

Abstract

A mathematical solution is presented for steady-state lateral response of earth and rock fill dams in canyons subjected to asynchronous excitation consisting of obliquely incident SH waves. The dam is idealized with a 2-dimensional shear wedge and the canyon is considered rectangular and consisting of flexible rock. A parametric study is undertaken to investigate the influence of (a) the angle of incidence, (b) the impedance ratio and (c) the canyon narrowness on the steady-state response, by considering in a simplifying way the effects of the dam-canyon interaction. The results demonstrate that the above factors may have a significant effect on the lateral response of the dam. For relatively flexible canyon rock, the effect of radiation damping is very important and, consequently, the assumption of rigid base may be very unrealistic. Due to interference phenomena, the response is not maximum for vertically propagating waves, but for waves incident at a certain angle. For obliquely incident waves travelling from left to the right, a gradual shift of the location of the peak response is observed from the mid-crest to the right side of the dam as the angle of incidence increases. Also, for very long dams subjected to high frequency obliquely incident waves, there is no amplification of the motion by the dam and, at a certain frequency of excitation; the presence of standing waves is indicated.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

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

Meeting Name

Second Conference

Publisher

University of Missouri--Rolla

Publication Date

3-11-1991

Document Version

Final Version

Rights

© 1991 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Mar 11th, 12:00 AM Mar 15th, 12:00 AM

Response of Earth Dams in Canyons Subjected to Asynchronous Base Excitation

St. Louis, Missouri

A mathematical solution is presented for steady-state lateral response of earth and rock fill dams in canyons subjected to asynchronous excitation consisting of obliquely incident SH waves. The dam is idealized with a 2-dimensional shear wedge and the canyon is considered rectangular and consisting of flexible rock. A parametric study is undertaken to investigate the influence of (a) the angle of incidence, (b) the impedance ratio and (c) the canyon narrowness on the steady-state response, by considering in a simplifying way the effects of the dam-canyon interaction. The results demonstrate that the above factors may have a significant effect on the lateral response of the dam. For relatively flexible canyon rock, the effect of radiation damping is very important and, consequently, the assumption of rigid base may be very unrealistic. Due to interference phenomena, the response is not maximum for vertically propagating waves, but for waves incident at a certain angle. For obliquely incident waves travelling from left to the right, a gradual shift of the location of the peak response is observed from the mid-crest to the right side of the dam as the angle of incidence increases. Also, for very long dams subjected to high frequency obliquely incident waves, there is no amplification of the motion by the dam and, at a certain frequency of excitation; the presence of standing waves is indicated.