Stability control of gob-side entry in deep extremely soft surrounding rock
Aiming at the large deformation,high fragmentation degree and support difficulty of extremely soft surrounding rock under the deep high stress,we took the 1232(3)gob-side entry of Dingji Coal Mine as engineering background,and studied the failure characteristics of surrounding rock and the principle and technology of stage control of surrounding rock in deep high stress soft rock gob-side entry using numerical simulation,field monitoring and underground test.The results show that as it gets further away from the heading face of the roadway,the stress asymmetry of the two sides of the roadway increases gradually.The peak stress at the solid coal side is 37.18 MPa,greater than 35.21 MPa at the coal pillar side.Stress concentration appears in the 50 m range of 1242(3)terminal line,which peaked at 33 MPa.Development degree of the surrounding rock plastic zone of the roadway ranks from large to small as:coal pillar side,solid coal side,roof and floor.From the complex surrounding rock change in the process of roadway excavation,the whole roadway can be divided into five typical stages of surrounding rock change to analyze the deformation and failure characteristics and failure mechanism of surrounding rock.It is revealed that under the action of high stress,the deformation of surrounding rock in deep soft rock roadway along goaf is large,showing obvious regional and asymmetry in space.Based on the preliminary design scheme of the roadway and the deformation and failure characteristics of the surrounding rock,the support scheme is adjusted in a timely and effective manner,and the roadway is comprehensively treated in a segmented,asymmetric and regional manner,forming a long-term mechanism for the control of the surrounding rock of the deep soft rock roadway,which provides theoretical and technical support for the mine pressure control in the same type of deep soft rock roadways.
deep high stressextremely soft surrounding rockgob-side roadwaysurrounding rock controlperiodic support
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