红层坝基重力坝深层滑动模式及抗力角论证

Argument of Deep Sliding Mode and Resistance Angle of Gravity Dam Foundation in Red Bed Region

亭子口大坝是修建在典型红层地区的混凝土重力高坝,岩层地质特点是地层倾角平缓,软弱夹层较多,这对大坝的深层抗滑稳定十分不利。在现阶段,等K法仍是重力坝深层抗滑稳定的主要分析方法,但在实际操作中,抗力角的不同取值对安全系数结果影响很大。重点分析了亭子口重力坝坝基深层抗滑稳定安全性,采用有限差分强度折减方法和刚体极限平衡等安全系数法对比研究了坝基深层滑面的差异和变化规律,探讨了刚体极限平衡方法中抗力角的合理取值,可为重力坝坝基抗滑稳定设计提供参考依据。

Tingzikou dam is a concrete gravity dam built in typical red rockbed region.The rock geological characteristics are of gentle dipped strata containing several weak interlayers,unfavourable to the deep anti-slide stability of the dam.At present,equal K value method is still the main method of analysing the deep stability against sliding of gravity dam.In practice,the variation of resistance angle greatly influences the result of the safety factor.The focus of this paper is to analyze Tingzikou gravity dam＇s stability safety against deep sliding,the difference of the deep sliding surfaces and their variation law using finite difference based strength reduction method and rigid body limit equilibrium based equal safety coefficient method.The reasonable value of resistance angle in the rigid body limit equilibrium method is discussed.This research provides sound basis for the design of gravity dam＇ s foundation stability against sliding.