Research On Damage Mechanism And Control Technology Of Deep Soft Rock Roadway In Chengjiao Mine

Chengjiao coal mine two-level east wing track roadway is mainly mudstone and sandy mudstone and other weak rock.The rock formation is low in strength,broken and muddy,and it is extremely difficult to maintain soft rock roadway.The deformation of the surrounding rock is very obvious,and the deformation of the surrounding rock has obvious time effect.The floor heave is very sensitive to the external disturbance.When the roadway is disturbed by external stress,the deformation speed of the bottom plate will increase sharply,which seriously restricts the safe production of coal mine.This paper studies the damage and damage mechanism of the east wing track roadway of Chengjiao mine by using the methods of field investigation,theoretical analysis,numerical simulation and industrial test,and puts forward the corresponding control technology for the specific situation of the east wing track roadway of Chengjiao mine.And the research results applied to Chengjiao mine.The main research results are as follows:1)There are obvious deep soft rock characteristics in the east wing track roadway of Chengjiao mine.The lithology of the test rock is mainly mudstone and sandy mudstone.The strength of the surrounding rock is low,and the compressive strength,cohesion and internal friction angle are small.The results show that the core rocks of the two level east wing track roadway are mainly kaolinite,and the rock specimen strength is relatively small and the plastic rheology is easy.The test results of the surrounding rock loosening circle show that the surrounding rock of the two level east wing track roadway loose range is large,belonging to IV,V large loose circle unstable rock.2)The damage mechanics analysis method of roadway surrounding rock is established.Through the mechanical analysis,the stress and displacement expressions of the fully elastic zone,elastoplastic damage zone and complete damage zone are obtained.At the same time,the influence factors of the radius of plastic damage area are analyzed.The mechanical properties of the surrounding rock in the early stage of the roadway support should be applied with sufficient support resistance and grouting reinforcement to improve the mechanical properties of the surrounding rock.3)The analysis model of damage and failure mechanism of surrounding rock in deep soft rock roadway was established by using FLAC3 D numerical simulation software.The stress and deformation of the surrounding rock and the distribution of plastic zone were analyzed.It was found that the deformation and damage of roadway surrounding rock were serious.The two corners and the two corner positions are mainly shear damage,the middle position of the two surfaces of the roadway and the middle position of the surface of the roof and floor are mainly in the form of tensile failure,so the two level east wing track roadway main mechanical of rock damage is tensile and shear failure.4)Through the comparison and simulation analysis of three kinds of supporting methods,the stability of roadway surrounding rock is analyzed from the characteristics of displacement distribution of surrounding rock,the stress distribution of surrounding rock and the plastic failure characteristics of surrounding rock.Bolting and grouting supports the peak of the surrounding rock to the inner edge of the surrounding rock,increasing the support strength,making the loose rock cement into one body,increasing the internal friction and cohesive force of the surrounding rock,improve the overall stability of the surrounding rock,effectively control the deformation of the surrounding rock.5)The continuous dynamic observation of the support in the east wing track roadway of the Chengjiao mine,the results show that the amount of roof sinking is 40.1mm and the bottom drum is 47.6mm and the two sides moved close is 55.4mm after 90 d of anchor support,the deformation velocity of the surrounding rock tends to be zero,and the surrounding rock is in steady state.The amount of the roof slab is 17.6mm,26.6mm,and the amount of the separation is basically stable after 30 d.The anchor form is applied to the scene.Rock deformation is effectively controlled.