Document Type : Research Paper
Authors
1 Assistant Professor, Abouraihan Scientific Complex, Tehran University, Iran
2 Scientific Board, Shooshtar Unit, Azad Islamic University, Iran
Abstract
When upstream water surface of an earth dam falls down rapidly and the upstream slope of the dam cannot be drained, the rapid drawdown analysis is necessary. There are several methods for rapid drawdown analysis including; Bishop, Ordinary, Janbu, Morgenstern-Price, Spencer, Lowe-Karafiath, United State Army Corps of engineers (USACE) and modified USACE. Modified USACE is presented by Lowe and Karafiath and is modified by Duncan, Wright and Wong. For simulation two models of SEEPE/W and SLOPE/W, are used. Drawdown velocity of 1, 2, 4 and 6 m/day are used in simulation. Simulations show that increasing drawdown velocity causes decreasing safety factor. Rapid drawdown analysis by Bishop, Morgenstern-Price, Spencer, Lowe-Karafiath, USACE and modified USACE give the same results for safety factor. Safety factor of rapid drawdown analysis will decrease 26% compared to steady state analysis on the average.
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