在深部软岩体中建造压缩空气储能洞室时，岩体的应变软化特性是洞室结构设计过程中不可忽略的重要因素。为提高洞室运行过程中围岩变形的预测精度，基于Hoek-Brown准则提出高内压洞室围岩力学响应的数值计算方法，考虑到开挖阶段应变软化与高内压运行阶段应变软化机制的区别，给出考虑岩体双向应变软化特性的洞室围岩应力路径，并研究围岩质量等级和软化程度对围岩应力路径的影响。结果表明： 1）围岩塑性区应力与其强度值密切相关。 2）相比于不考虑应变软化的情况，考虑应变软化后围岩的应力分布存在显著差异，在开挖阶段塑性区内环向应力更小；而在高压储气阶段，塑性区内环向应力更大。 3）考虑应变软化后围岩位移显著增加，塑性区范围也大幅增加，在塑性扩张阶段塑性区半径的增加速度也更快。4）由于围岩变形是高内压洞室衬砌设计的关键参数，因此，在进行高内压地下洞室结构设计时，对于Ⅲ级或者更差的围岩，不应忽视其应变软化特性。
Construction of compressed air energy storage caverns in deep, medium-to-soft rocks requires consideration of the strain-softening characteristics of the rock mass, a critical factor that cannot be overlooked in cavern structural design. To improve the predictive accuracy of surrounding rock deformation during cavern operation, a numerical method for the mechanical response of surrounding rock in high-pressure caverns was proposed based on the Hoek-Brown criterion. It is crucial to distinguish between strain-softening mechanisms during the excavation phase and those during the high-pressure operational phase. A stress path for the cavern’s surrounding rock was presented, incorporating the bidirectional strain-softening characteristics of the rock mass. The influence of surrounding rock quality grade and softening degree on the stress path was investigated. Results indicate the following: (1) Stress within the plastic zone of the rock mass correlates closely with its strength values. Compared with scenarios in which strain-softening is not considered, incorporating strain-softening leads to markedly different stress distributions. During the excavation phase, circumferential stresses within the plastic zone decrease, whereas during the high-pressure gas storage phase, these stresses increase considerably. (2) Incorporating strain-softening substantially increases rock mass displacement and considerably expands the plastic zone. The rate of increase in the radius of the plastic zone accelerates during the plastic expansion phase. (3) Rock mass deformation is a critical parameter in the design of high-internal-pressure cavern linings. (4) Therefore, the strain-softening characteristics of Grade Ⅲ or poorer rock masses must be taken into account during the structural design of high-internal-pressure underground caverns.
