Study On Surrounding Rock Control Technology Of Mining Roadway Under Coal Pillar Near Coal Seam In Dafosi Mine

This article takes the transportation along the 40111 working face of Dafosi Mine as the research object.Through on-site investigation,data analysis,peeping of the development of surrounding rock fissures and physical and mechanical determination of on-site rock samples,feature and reason of surrounding rock's deformation and breaking in testing roadway are analyzed.Through theoretical analysis and numerical simulation,the influence of different spacing between the lower layers of coal pillars on the stability of the surrounding rock of the roadway is analyzed.Based on the influence of layer spacing changes on the stability of surrounding rock and the highstrength and stable support core under the coal pillars,three reinforcement and support schemes suitable for roadways with different layer spacings are proposed,which are verified by on-site industrial tests.The main researches are:(1)The transportation along the 40111 working face of Dafosi Mine belongs to the short-distance the failure features of testing roading's surrounding rock are mainly due to the large amount of roof subsidence,the inward movement of the two sides and a large amount of bulge,the low anchoring force of the anchor cable,and the failure of the anchor cable often occurs.The analysis reason is that the influence of the upper coal pillar,the low strength of the surrounding rock,the movement of the overburden caused by the roadway excavation and the unreasonable support are the main reasons for the failure and instability of the surrounding rock of the roadway.(2)The theoretical calculation and FLAC3 D numerical simulation software are used to analyze the influence of the change of the distance between the lower coal pillars on the stability of the roadway surrounding rock.The vertical stress decreases,and the asymmetry of the stress concentration in the high-stress areas of the two sides increases;as the distance between the roadway and the upper coal pillar layer decreases,the displacement of the surrounding rock of the roadway increases,and the displacement gap between the two sides increases;The damage range of the plastic zone increases,and the gap between the two sides of the plastic zone damage increases.(3)Based on the characteristics and cause analysis of the instability of the surrounding rock during transportation of the 40111 working face,the anchor cable anchoring force reliability improvement device is proposed.The anchor cable is installed with a tubular buckle to make the anchor cable squeeze the anchoring agent and fully stir it;propose anchoring Agent delivery device to improve the anchoring performance of the anchor rod cable.Based on the principle of anchor-cable coordinated support,a high-strength and stable anchor-net-cable coordinated support technology is proposed,and the optimal matching value of the pre-tightening force of the anchor cable in the transportation of 40111 working face is obtained through calculation.(4)Based on the influence of the change of the distance between the lower layers of coal pillars on the stability of the surrounding rock of the roadway and the highstrength and stable anchor-net-cable support technology,the reinforcement support schemes suitable for the roadways with different layers are proposed.Numerical simulation is used to analyze the stability of the surrounding rock of the roadway after the reinforcement of the three reinforcement schemes.After the reinforcement and support,the stress reduction area of the surrounding rock of the roadway is significantly reduced.The high-stress area shifts to the deep part of the surrounding rock.The deep separation layer has dropped significantly,and the damage range of the plastic zone of the surrounding rock of the roadway has been greatly reduced.It shows that the support of the surrounding rock in the shallow part of the roadway is significantly improved after the reinforcement and support,and the deformation and failure of the surrounding rock of the roadway is effectively controlled.(5)Reinforcement support scheme tests were carried out in the transport tunnel test section of 40111 working face.The amount of separation of the surrounding rock in the deep part of the roadway was reduced,the anchor cable bearing capacity performance was better,and the deformation of the roadway surrounding rock was effectively controlled.Improving the effect of roadway support and ensuring the smooth mining of the 40111 working face is the further improvement of the support technology of the Dafosi Mine,which has realized safe and efficient mining of the mine.The dissertation has 61 figures,9 tables and 84 references.