The Numerical Analysis Of Roadway Stability By Fault Cutting Surrounding Rock In A Mine

With the development of underground space engineering in depth,large,long and wide,the geological structures in strata become relatively complex.Discontinuous structural planes such as faults and structures determine the mechanical properties of engineering rock mass.Therefore,it is particularly important to study the influence of faults on roadway stability.In this paper,based on field investigation and summary of research,the method of parameter weakening and interface are proposed to characterize faults separately,and the appropriate method of fault characterization is selected by FLAC^3D,and the law of ground pressure manifestation of roadways is studied.The main conclusions are as follows:（1）To simulate the fault cutting surrounding rock,the selection of the method of parameter weakening or interface should be based on the engineering geological conditions of field faults.The methods of parameter weakening and interface deal faults with different ways,which causes the continuity of the faults and the surrounding rock is inconsistent,thus resulting in a huge difference between the two initial ground pressures.This mine prefer to select the method of parameter weakening.（2）The influence of ore body mining on the stability of roadway tends to be consistent according to the two calculation methods of results.The main reason for the increase of tensile stress of the surrounding rock of roadway is the north ore body mining of 1330 m,and the secondary cause is the faults.There are no fault in the south side of the ore body and the roadway is connected,and the south ore body mining has little influence on the stability of the roadway.（3）The integrity of the top pillar near the fault controls the slip of the fault,thus it also controls the increase of tension stress in surrounding rock of roadway.In order to reduce the increase of tension stress of surrounding rock due to fault slip,it is necessary to ensure the integrity of the top pillar near the fault.the thickness of the top pillar in the middle section of 1230 m near the fault should be increased appropriately in deep mining,and the goaf in the middle section of 1230 m should be filled in time to ensure that the top pillar in the middle section of 1230 m is not destroyed.Similar measures should be taken to protect the top pillar in the middle section of 1180 m when in deep mining,so as not to cause the development of the roadway in the middle section of 1230m serious wall caving and roof collapse.（4）In deep mining,the roadway should be located at a distance of more than 12 m from the boundary line of the lower wall of the ore body.（5）Prestressed anchor support can control the tensile fatigue failure of roadway,and the non-prestressed anchor support with bending hook has little effect on the tensile fatigue failure of roadway.The research shows that the application of 8 kN prestressing force can play a good supporting role for the pulled roadway,and the tensile stress decreases by 19.0-29.8%.If 32 kN prestressing force is applied,the tensile stress decreases by 28.6-38.0%.