Study On Stress Distribution Of Mining Surrounding Rock Based On Direct Current Method

With the increase of the depth of coal mining,the stress distribution and change of the surrounding rock are more complicated due to the complicated geological conditions and mining conditions,which have great influence on the roadway support and the rock and rock dynamic disaster,and effectively detect the surrounding rock Stress distribution and change is particularly important.This paper presents the idea of using the direct current method to study the stress distribution of the surrounding rock,and analyzes the stress distribution and the change detection principle of the mining surrounding rock based on the direct current method.The experimental analysis analyzes the coal samples in different Stress and fracture conditions,and the stress response law of the stress distribution of the surrounding rock is analyzed and verified.(1)The principle of direct current method for detecting the stress distribution of surrounding rock is analyzed.The direct current method is based on the conductivity difference of coal and rock mass(the resistivity of coal rock mass).The evolution of coal body conductivity and pore fissure distribution is the main factor to determine the change of resistivity in the process of loading and unloading.The coal body is mainly composed of electron conduction and different stress levels,and its internal pore fractures are different,which shows different resistivity response laws.In the unloading area,the macroscopic pore fissures are distributed in large quantities,The apparent resistivity is the largest,the stress concentration is closed,the original pore fissures are closed in large quantities,the apparent resistivity is the lowest,and the pore fissures in the original stress zone are not affected by the mining.The apparent resistivity is between the pressure relief zone and the stress concentration area.(2)The experimental results show that the apparent resistivity of coal and rock under different stress levels and pore fissures is analyzed.It is found that the apparent resistivity decreases with the increase of stress at the beginning of loading.In the middle stage of loading,the apparent resistivity increases slightly with the increase of stress,After loading to damage,with the increase in stress as the resistivity increased multiple.(3)The method of direct current method is used to detect the dynamic pressure zone of the 11702 working face in the Nuo Dong coal mine.It is found that the pressure relief zone in the front face of the working face is in the range of 0m ~ 15 m,roadway loose circle range is about 0m ~ 4m away from the coal wall,stress concentration zone is generally 4m ~ 9m.The results show that the direct current method can be used to detect the distribution of stress in the surrounding rock of the mining area,and the results show that the direct current method can be used to detect the stress distribution of the surrounding rock.Compared with the traditional test method,the direct current method has the advantages of high efficiency and fastness,and its regional detection result is more comprehensive and intuitive.