Study On Surrounding Rock Deformation Law And Control Technique Of Extra Thick Coal Seam And Dynamic Pressure Roadway In Cuimu Coal Mine

The underground roadway is the lifeline for underground mining,and bears the heavy responsibility of underground transportation,ventilation and pedestrians.The effect of roadway support will directly affect the underground safety production.This article comprehensively applies field surveys,theoretical analysis,numerical simulations,laboratory experiments and field tests,the law of deformation and deformation characteristics of the surrounding rock of the return wing of the north wing of Cuimu coal mine was systematically studied and reasonable control technique was proposed,the main research contents and research results are as follows:（1）Thorough scene investigations and collect the deformation characteristics and supporting conditions of the roadway.From the results,the left side of the roadway（close to the side of the 21306 working face）was moved and the deformation in the road was significantly larger than the roof and the bottom of the roadway.Floor deformation are also quite serious.In order to better formulate support plans,stress tests using the hollow-core inclusion stress relief method were conducted on the site.The maximum principal stress was determined to 24.3MPa,the azimuth angle was 268.5°.The included angle is 74.5°.The physical and mechanical parameters of the coal seam and roof rock are also tested.（2）Since the north wing return roadway and the 21306 working face are almost parallel to the mining direction,in order to maintain the stability of the roadway surrounding rock,it is necessary to determine a reasonable protection pillar width,using the FLAC^3D numerical simulation software to simulate the protective pillar width is20m,30m,40m,50m,60m,and 80m,the deformation law and stress distribution law of surrounding rock,the results show that when the protective pillar width is 80m,the roadway surrounding rock is less affected and if the width of working face is originally designed,the minimum width of protective pillar is only 45m.In order to maintain the long-term stability of the roadway,the width of the working face is shortened so that the protection pillar is increased to 95m;the three large roadway in the north wing will affect each other and the protection pillar needs to be determined.When the distance between the roadway is more than 40m,the mutual influence is small,and the distance between the roadways in the field is greater than 40m,so the pillar of protection between the roadways does not need to increase.（3）In the full seam roadway,the semi-circular arched section is more conducive to the long-term stability of the maintenance roadway,so the cross-sectional shape of the new excavation roadway is changed to a semi-circular arched section;according to the simulation results,the two concepts are selected using the idea of classification support.In different roadway conditions,according to the characteristics of the floor drum that easily lead to the occurrence of the kick drum,the bottom control technology of the cutting board grooving and the anchor cable was adopted.（4）According to the results of the study,industrial trials at the site,reinforce the roadway where the existing roadway can meet the requirements of use.For the failure to meet the requirements of the use,full-face expansion and new excavation roadway rational use of two support schemes in light of the actual situation.In the field to install the station to detect the control effect of roadway surrounding rock.From the test data obtained from the three stations installed on the spot,the maximum displacement of the roof and floor is 236mm and the maximum displacement of the two sides is 163mm,which can meet the requirements.