地震荷载作用下地下岩体洞室位移特征的影响因素分析

用FLAC3D初步分析了地震荷载作用下埋深、洞室形状、地应力特征对地下岩体洞室位移特征的影响。分析结果表明:地震荷载作用下,地下洞室位移响应随埋深的增加而减小,当地应力侧压系数λ≥1(特别是λ>2时),洞室位移响应存在临界埋深(200～300m),并随地应力侧压系数的增加而减小。洞室断面形状对洞室位移响应有一定影响,圆形断面洞室拱顶和拱底位移较矩形和马蹄形小。分析结果还表明,随地应力侧压系数的增加洞室位移明显减小,幅度随埋深的增加有减小趋势,地应力侧压系数λ<1时的洞室位移量值及随侧压系数的变化幅度明显大于地应力侧压系数λ>1时的情况。本文的工作可为工程设计提供一些概念性指导。

Study on influence factors of rock cavern displacement under earthquake

The influence of overburden and cavern shape as well as in-situ stress condition on the displacement characteristics of rock cavern under earthquake were analyzed.It was reported that the cavern displacement decreased with the increasing overburden.When λ≥1(especially λ>2),there was a critical depth(200～300 m)which decreased with the increasing λ(side pressure coefficient).It was also suggested that the displacement of circular cavern was less than that of triangular and hoof-like cavern under the same loading condition.As well,the cavern displacement decreased with the increasing λ(side pressure coefficient),and the decreasing rates tended to decrease with the increasing overburden.It was further revealed that the cavern displacement and its decreasing rate with increasing λ at the condition of λ<1 were significantly larger than those of λ>1.The present work could be used as a primary guidance to the anti-earthquake design for underground cavern.