动荷载作用下地下岩体洞室应力特征的影响因素分析

用FLAC3D初步分析了动荷载作用下埋深、洞室形状、地应力特征对地下岩体洞室应力特征的影响。分析结果表明:动荷载下,随着埋深的增加,各种洞型应力量值有明显的减小趋势;地应力状态对地形洞室的应力响应有较明显的影响,在自重地应力为主的情况下,洞室拱顶、拱底地最小主应力处于拉应力状态,而构造地应力为主的情况下,洞室拱顶、拱底最小主应力处于压应力状态,且随着侧压系数的增加,洞室的应力由较明显的减小趋势;动荷载作用下,不同断面形状的洞型应力响应有一定区别,圆形洞室应力响应最小,矩形洞室应力响应最大,随埋深、地应力的增加,洞形对洞室应力响应影响减小,当埋深超过300 m后,洞型对应力的影响变化程度不大。

Study on the Factors Influencing Stress Characteristics of Rock Cavern under Earthquake

The influence of buried depth, sectional shape of cavern and in-situ stress condition on the stress characteristics of rock cavern under earthquake are analyzed in the present paper by FLAC^3D. It is reported that the stress of various caverns clearly decreases with the increasing overburdens. It is also reported that the minimum stress of caverns is tensile when the horizontal stress is dominant; while vertical stress is dominate, the minimum stress of caverns is compressive ; as well, the cavern stress clearly decreases with the increasing side pressure coefficient. It is further suggested that the stress of circular shape cavern is less than that of hoof shape and triangular cavern under the same loading condition. In addition, the influencing of cavern sectional shape on the stress condition decreases with the increasing buried depth and insitu stress, when the buried depth is larger than 300 m, the influencing of cavern sectional shape is very slight.