金川二矿区地应力特征及其对巷道变形破坏的影响研究

随着地下工程建设不断向地球更深处发展,高地应力已成为影响深部巷道围岩稳定性的关键因素.针对金川二矿区高地应力问题,总结研究区地应力分布特征,采用离散元数值方法计算了3种不同地应力条件下巷道围岩的变形破坏过程.所得主要结论包括:(1)研究区地应力分布离散性较强,已测最大主应力多数为水平方向,但随着埋深的增加,竖直主应力逐...

Study on Ground Stress Characteristics and Its Influence on Roadway De-formation Failure in Jinchuan No.2 Mining Area

With the development of underground engineering construction to the deeper earth，high ground stress has become a key factor affecting the stability of deep roadway surrounding rock.Under the action of high in-situ stress，the mechanical behavior characteristics and microstructure of deep rock mass change significantly compared with shallow rock mass，which is the cause of frequent mining accidents in deep underground engineering，and also the research focus in the field of rock mechanics.Taking Jinchuan No.2 mining area，a typical high in-situ stress mining area，as the background，this paper summarizes the in-situ stress distribution characteristics of the study area according to the previous measured data.On this basis，the discrete element numerical simulation method was used to calibrate the rock mechanical parameters based on the laboratory test of rock samples in the study area，and the tunnel models under three different in-situ stress conditions were established.According to the simulation results，the development process of roadway surrounding rock deformation under different conditions was described，the deformation failure characteristics of roadway in each model were compared，the influence of ground stress on roadway deformation failure was analyzed，and the corresponding control methods were proposed.The main conclusions of the study include：（1）Due to the influence of complex geological background，the distribution of ground stress in Jinchuan No.2 mining area is highly discrete.In the measured data，there are more than 80% of the measure points show that maximum horizontal principal stress is greater than the vertical principal stress，and the stress of primary rock is mostly horizontal.In shallow mining areas，the growth rate of horizontal stress is greater than that of vertical stress.With the increase of buried depth，the increment speed of horizontal stress gradually decreases，and the vertical principal stress gradually approaches the maximum horizontal principal stress.（2）Without the influence of structural planes，the deformation mode of homogeneous surrounding rock roadway is mainly roof subsidence and floor heave，and the deformation is mainly dependent on plastic flow.With the continuous increasing of in-situ stress，the total deformation and deformation velocity of roadway are increasing.Ground stress does not change the deformation mode of roadway surrounding rock，but intensifies its failure degree.（3）When roadway excavation is carried out under geological conditions dominated by horizontal ground stress，support of roof and floor should be adopted to maintain the overall stability of roadway.In addition，because of the significant time effect of plastic deformation，the cracking caused by the compression of roadway lining also has a certain lag.Thus，the deformation of roadway should be regularly monitored in the construction in case of the dangerous deformation.The research results can provide theoretical reference for safe and efficient deep mining in Jinchuan No.2 mining area.