深部软岩地下工程围岩稳定性差且具有长期流变效应,由于支护不利导致围岩产生大变形破坏问题趋于突出。针对以上问题,以某深部软岩巷道工程建设为例,采用现场监测、数值模拟等方法,分析围岩长期变形趋势及破坏机理;针对围岩破坏特征,提出"刚柔"结合的软弱大变形巷道围岩新型支护方法:考虑围岩不同深度破坏情况不同,采用不同注浆方法分区域加固,形成"刚性"承载圈,并在巷道最外部设置缓冲层及可缩性U型钢支架,形成柔性加固圈。利用有限元模型对其支护效果进行数值模拟,结合现场监测变形数据分析,验证了新型支护方案的合理性。
Underground engineering in deep soft rock has poor stability and long- term rheological property. Large deformation and damage of surrounding rock induced by unreasonable support has been more outstanding,and the iterative maintenance will not only seriously influence the safety and stability of engineering,but also greatly increase the maintenance cost. Aiming at the above problems,taking the construction of a deep soft rock roadway as example,the long- term trend of deformation and failure mechanism of surrounding rock were analyzed by using field monitoring and numerical simulation methods. According to the failure characteristics of surrounding rock,a new rigid- flexible combined support method for soft rock roadway with large deformation was put forward. Considering the different damage situation in different depth of surrounding rock,different grouting methods were used for reinforcement in different regions so as to form rigid load- bearing ring,what's more,the buffer layer and deformable U- shape steel support were set up in the external area of roadway to form flexible reinforcing ring. The finite element model was used to simulate the support effect,and combined with the analysis on field monitoring data of deformation,the rationality of new support scheme was verified.