Three-dimensional upper bound limit analysis of underground cavities using nonlinear Baker failure criterion

基于非线性Baker破坏准则的地下硐室三维上限极限分析

A generalized nonlinear Baker failure criterion is employed with the upper bound limit analysis to study the surrounding rock stability of underground cavities. A three-dimensional(3D) failure mode is established by extending the two-dimensional(2D) failure mode, which offers an upper bound expression of the surrounding rock pressure. This method is validated with a series of examples before the influence of four parameters of scale parameter, curvature parameter, shift parameter and lateral pressure coefficient, on the surrounding rock pressure is analyzed. According to these results, failure ranges of the underground cavities are determined. The following conclusions are reached:(1) the proposed approach is more accurate to predict surrounding rock pressure than the Mohr-Coulomb failure criterion;(2) the surrounding rock with large scale parameter, curvature parameter, shift parameter, and lateral pressure coefficient can lead to a more stable underground cavity;(3) the failure range in 3D mode can be predicted according to the upper bound solutions.

将广义非线性Baker破坏准则与上限极限分析法相结合,研究地下硐室围岩稳定性。通过扩展地下硐室二维破坏模式,建立一种三维破坏模式;基于建立的三维破坏模式,给出围岩压力上限表达式。在分析尺度参数、曲率参数、位置参数和侧压系数对围岩压力的影响前,通过一系列实例验证该方法的有效性。根据研究结果,确定地下硐室的破坏范围。得到以下结论:(1)采用本文提出的方法预测的围岩压力比基于Mohr-Coulomb破坏准则预测的围岩压力更精确;(2)尺度参数、曲率参数、位置参数和侧压系数越大,围岩越稳定;(3)根据上限解可以预测三维模型的破坏范围。