Study On Failure Mechanism And Deformation Control Of Surrounding Rock In Large-section Soft Rock Roadway Of Fault Group

Due to the combined effects of factors such as fault structure,section size,and rock mass properties,the failure mechanism and stability control difficulty of largesection soft rock roadways in fault zones are complex,which seriously restricts safe and efficient mining production.This article takes the 109 track roadway of Yangliu Coal Mine,Huainan Mining Group,as the background,and comprehensively uses methods such as field investigation,theoretical analysis,and numerical simulation to analyze the stress change law of surrounding rock under the influence of faults,study the deformation and failure characteristics of the surrounding rock in the large roadway,point out the problems of the original support scheme,propose a segmented support scheme for the large roadway,and conduct industrial experiments on site to evaluate the application effect of the support scheme.The main research results are as follows:(1)By establishing numerical models with different fault dip angles and fault damage zone thicknesses,the stress change law of the surrounding rock of the roadway under the influence of faults is analyzed.The simulation results show that the vertical and horizontal stresses of the hanging wall rock near the fault structure and the vertical stress of the footwall rock are all greater than the original rock stress,while the horizontal stress of the footwall rock is lower than the original rock stress.The stress distribution of the fault structure has a greater impact on the footwall rock than on the footwall rock,and the impact range and degree increase with the increase of the fault dip angle and fault damage zone thickness.(2)Using drilling observation and theoretical calculation,combined with the numerical simulation of the track roadway affected by the fault group,the characteristics of roadway surrounding rock failure under the influence of the fault group are analyzed.The research shows that the theoretical calculation result of the range of roadway surrounding rock failure is 2.37-5.18 m,the simulation result of the range of plastic zone development is 1.20-5.72 m,and the measured result of the deep fracture range is 2.7-4.2 m.(3)Based on the deformation and damage characteristics of the surrounding rock in the 109 mining area track roadway,the track roadway is divided into fault influence segment,fault-penetrating segment,and non-fault influence segment.It has been determined that the “Anchor net,shed,shotcrete and grouting” support method should be used in the fault influence segment and fault-penetrating segment,while the “Anchor net,shed,cable and shotcrete” support method should be used in the non-fault influence segment.Based on this,three support schemes have been proposed for each support segment,and the optimal support scheme for each segment of the 109 mining area track roadway has been determined by simulating the support effects of each scheme.(4)Industrial tests were carried out for segmented support of the track roadway in the 109 mining area,and field measurements were conducted for anchor rod stress state,tunnel surface displacement,and deep rock fracture range.The maximum deformation of the roof and floor and the two sides was only 62 mm and 51 mm,and the maximum deep rock fracture range was only 60% of the original support scheme.The results showed that the segmented support scheme developed was reasonable and effective,and could provide safety for the long-term use of the track roadway.There are 107 figures,22 tables and 71 references in this thesis.