针对新疆沙吉海矿区中生代复合型软岩产生的顶板离层冒落、侧墙鼓出、底板鼓起等非线性大变形破坏现象,综合应用现场工程地质调查、理论分析、数值计算、物化分析、软岩水理作用测试、现场测试等手段和方法,深入分析本区中生代复合型软岩巷道围岩的分子膨胀+岩体结构面错动+开挖扰动的复合破坏机制,提出以恒阻大变形锚网索耦合支护为核心的主动支护技术体系。通过恒阻装置充分释放围岩膨胀能和塑性能,减小支护荷载及高应力集中,同时借助高阻性能抑制过大有害变形,合理控制围岩塑性圈;然后通过锚网索二次耦合支护消除围岩塑性大变形、层间软弱结构面的错动引起的围岩–支护之间的变形不协调,并采用注浆锚管控制底鼓大变形,最终形成围岩–支护结构协同承载体系。基于非线性大变形力学设计方法及数值分析,进行施工过程设计及参数设计。工程实践表明,该技术得到成功应用,保证了巷道的稳定。
In view of failure phenomena with nonlinear large deformation including roof subsidence,sidewall bulge and floor heave occurred in mesozoic compound soft rock of Shajihai coal mine in Xinjiang,according to the methods of geological survey,theoretical analysis,numerical calculation,physicochemical test,hydrological properties test of soft rock,in-situ test,the composite failure mechanism of molecular expansion,movement of structural plane and excavation disturbance for mesozoic compound soft rock roadway in this area is analyzed deeply.Then,an initiative supporting technology system which is based on constant resistance with large deformation coupling support is proposed.Firstly,through constant resistance device,the swelling and plastic energy of surrounding rock is released fully;and the support load,stress concentration are reduced.With the aid of high-resistance performance,the excessive harmful deformation is restrained;and the plastic zone of surrounding rock is controlled reasonably.Secondly,uncoordinated deformation between the surrounding rock and support,which is caused by large plastic deformation and the dislocation of weak structural plane,is eliminated through the secondary bolt-net-cable coupling support.Grouting bolt is used to control large deformation of floor heave. Ultimately,a collaborative bearing system of the surrounding rock-supporting structure is formed. The optimizations of construction process and parameter design are studied based on the design method of nonlinear large deformation mechanics and numerical analysis. Engineering practice shows that this technology has been successfully applied to ensure the stability of roadway.