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基于卸荷岩体力学基本理论,运用三维有限差分软件,提出以塑性体积应变增量变化区间与不同卸荷区域岩体力学参数相对应的卸荷模拟方法,模拟了不同侧压系数条件下开挖洞周附近围岩最大体积应变增量以及围岩损伤范围的变化情况。数值模拟结果表明:当侧压系数较低时,洞周附近围岩的塑性体积应变增量区域的外边界近似为竖向椭圆形,随着侧压系数的增大,其外边界逐渐向圆形变化,最后变为横向椭圆形。侧压系数越大,围岩的卸载效应越显著,洞周附近围岩的塑性体积应变增量就越大,其所产生的围岩损伤范围也相应越大。利用所获得的结果,可以为深埋隧洞的稳定性分析以及支护设计提供依据。
Based on the basic mechanics theory of unloading rock mass and using three-dimensional finite difference software, the unloading simulation method corresponding to the change range of plastic volumetric strain increment and the mechanical parameters of rock mass in different unloading areas is proposed. The simulation results under different lateral pressure coefficient The maximum volumetric strain increment of surrounding rock near the burrowing hole and the change of the damage range of the surrounding rock. Numerical simulation results show that when the lateral pressure coefficient is low, the outer boundary of the plastic volumetric strain increment in the surrounding rock near the hole is approximately vertical oval. As the lateral pressure coefficient increases, the outer boundary of the rock mass gradually turns round Shape change, and finally into a horizontal oval. The larger the lateral pressure coefficient is, the more obvious the unloading effect of surrounding rock is. The greater the plastic volumetric strain increment of surrounding rock around the hole is, the larger the surrounding rock damage range is. The results obtained can provide the basis for the stability analysis and support design of deep tunnels.