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巷道开挖卸荷即巷道附近围岩应力重分布,卸荷速率影响应力场,开挖卸荷本质上是动力问题。根据弹性力学知识并假定卸荷过程符合时间参数t 0的函数,基于Hamilton原理,获得考虑卸荷时间的巷道附近应力场演变规律。系统概括不同埋深条件下巷道附近应力场特征,并针对深埋巷道地应力较围岩强度大的特点,详细地分析考虑剪切及拉伸破坏时巷道附近破坏特征。结果表明,自巷道壁由近及远出现以剪切破坏、未破坏、拉伸破坏为主要特征的现象,也即以“剪切破坏+未破坏+拉伸破坏”为主要特征的状态是巷道附近可能破坏模式之一,并且该现象与围岩性质及卸荷时间相关。
Roadway excavation unloading is the surrounding rock roadway stress redistribution, unloading rate affect the stress field, excavation unloading is essentially a dynamic problem. Based on the knowledge of elastic mechanics and assuming that the unloading process accords with the function of time parameter t 0, the evolution law of stress field near the roadway considering the unloading time is obtained based on the Hamilton principle. The characteristics of the stress field near the roadway under different burial depths are systematically summarized. According to the characteristics that the ground stress of the buried tunnel is stronger than the surrounding rock strength, the damage characteristics near the roadway under the shear and tensile failure are analyzed in detail. The results show that the phenomenon characterized by shear failure, undrained failure and tensile failure as the main features from the near and far of the roadway wall, that is, the state characterized by “shear failure + failure + tensile failure” Is one of the possible damage modes near the roadway, and the phenomenon is related to the nature of the surrounding rock and the unloading time.