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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。
In view of the fact that the mechanical parameters of the surrounding rock deteriorate after excavation of large-scale underground powerhouse and the defects that the deformation of large-scale underground powerhouse does not have relevant normative reference, based on the analysis of the instability mechanism of surrounding rock of underground powerhouse and based on the idea of strength reduction method, The calculation method of the reduction of surrounding rock mass degradation in large-scale underground powerhouse is put forward and the dynamic early-warning system of surrounding rock deformation is established. The system uses yield proximity index to determine the deteriorated area of surrounding rock and reduce the deformation modulus, cohesion force and tensile strength value in the degraded area. Based on the deformation of surrounding rock and the volume of deteriorated area during the reduction calculation, energy is released One of the sudden change as a criterion for the surrounding rock instability to obtain deformation warning of the surrounding rock instability and comparative analysis with the site deformation monitoring values in order to achieve rapid determination of the stability of the surrounding rock. The analysis of the underground powerhouse shows that the method can provide a quantitative basis for judging the stability of caverns and meets the needs of underground engineering construction well.