考虑岩体劣化的大型地下厂房围岩变形动态监测预警方法研究

针对大型地下厂房洞室开挖后围岩力学参数发生劣化的事实，以及大型地下厂房允许变形无相关规范参考的缺陷，在分析地下厂房围岩失稳机制基础之上，基于强度折减法思想，提出大型地下厂房围岩劣化折减计算方法，建立围岩变形的动态预警路线体系。该体系应用屈服接近度指标确定围岩的劣化区域，折减劣化区域内的变形模量、凝聚力及抗拉强度值，在折减计算过程中依据围岩的变形、劣化区体积、释放能量三者之一发生突变作为围岩失稳判据，获得围岩失稳的变形预警值，并与现场变形监测值对比分析，从而实现围岩稳定状况的快速判别。地下厂房实例分析表明，该方法可为洞室稳定性判断提供定量依据，较好地满足了地下工程建设需要。

Study of dynamic early warning method of surrounding rock deformation monitoring for large underground powerhouse considering rock degradation

For the fact that rock mass degradation is not taken into account in the appraisal method for surrounding rock stability and the insufficient norms reference to deformation characteristics of the large underground powerhouse, considering the fact that the actual rock mass properties change in the excavation of underground powerhouse, based on strength reduction method idea, a new stability analysis method of surrounding rock for large underground powerhouse is proposed. At first, yielding approach index is used to appraise the excavation degradation zone of surrounding rock in numerical simulation. Secondly the deformation modulus and cohesive strength are reduced in the degradation damage zone. Then the failure criterion could be determined through the displacement, damage zone and energy release amounts mutation. Meanwhile, the early-warning displacement is analyzed in the process of rock degradation, and it can distinguish the stability of surrounding rock rapidly. At last, by analyzing an example of underground powerhouse, it is shown that the proposed method can provide quantitative basis for underground powerhouse stability; and it meets the need of underground projects fairly.