土质隧道围岩未支护段破坏模式分析

Analysis of Un-supported Section Failure Mode of Soil Surrounding Rock in Excavation

基于土质隧道围岩破坏模式的模型试验结果,通过临界尺度分析了未支护段围岩发生破坏的机理。根据围岩破坏形态和破坏机理建立了分析模型,推导了未支护段围岩发生自稳破坏、进尺破坏和不破坏的理论条件,并结合工程实例进行了分析。研究表明:围岩开挖的临界尺度控制了围岩的破坏模式,当开挖跨度或进尺分别大于相应的临界尺度时,未支护段就分别发生自稳破坏模式或进尺破坏模式;分别得到了发生自稳破坏、进尺破坏和不破坏的理论条件及破坏高度计算式;工程实例验证表明理论分析结果与实际相符。

Based on the model test result of failure modes of soil surrounding rock, the failure mechanism of un-supported section was analyzed through the definition of critical scale. The theory conditions of self- stability failure, footage failure and no failure in un-supported section were researched by using the analyzing model which founded on failure mechanism and configuration of soil surrounding rock, and the analysis was conducted by engineering example. The results show that the critical scale in excavation controls the failure modes of soil surrounding rock. If the span and footage values are larger than the corresponding critical scale, self-stability failure and footage failure will take place in un-supported section. The theory conditions and failure height expressions of self-stability failure, footage failure and no failure were achieved. The validation result of engineering example shows that the theory analysis is consistent with the practice.