Study On Bolt-Net Support Technology Of Roadway In Soft Broken Unstable Coal Seam In Shihao Mine

In order to study the bolt-mesh-anchor support technology of roadway in soft broken unstable coal seam.Based on the engineering background of 12162 working face roadway in Shihao Mine,aiming at the problem of surrounding rock control of roadway in soft broken unstable coal seam,the geological and mechanical characteristics of surrounding rock of roadway in soft broken unstable coal seam are systematically studied by means of field investigation,theoretical analysis,laboratory test,numerical simulation and underground industrial test.The differential support scheme of bolt-mesh-anchor in 12162 working face roadway is designed.Aiming at the phenomenon that the shallow anchorage hole of roadway soft broken roof is easy to destabilize and destroy at the construction site of bolt-mesh-anchor,the quality degradation inhibition device of roof anchorage hole is developed,and the working principle of the device is expounded.The value verification of support design scheme and device was completed in the working face roadway of 12162 underground.The main conclusions of this paper are as follows :(1)The geological and mechanical characteristics of soft and broken unstable coal seam roadway in Shihao Mine are mastered.The results show that the coal body of 12162 working face belongs to soft coal type.Within the range of roadway excavation on working face,the thickness of coal seam changes greatly,the strength of roadway regeneration roof is low,and it is soft and easy to break.According to whether the direct roof of the roadway is coal seam,the12162 working face roadway is divided into general and abnormal conditions,and the differential design of bolt-mesh-anchor support parameters in different sections of the same roadway is carried out.(2)According to the geological conditions of different surrounding rocks in the 12162 working face roadway,the differentiated design of bolt-mesh-cable support parameters was carried out,and the support effects of different design schemes were compared and analyzed by using the numerical simulation method.Under the premise of meeting the requirements of reliable support of roadway surrounding rock,the most suitable design scheme of bolt-meshcable support parameters was obtained by comprehensively considering the support cost and construction workload.(3)Aiming at the problem that the shallow part of the roof anchorage hole is easy to collapse in the field construction of the anchor net cable support in the soft top coal roadway section of the 12162 working face roadway of Shihao Mine,which leads to the failure of the installation of the roof bolt(cable),a quality deterioration suppression device for the roof anchorage hole is developed,and the working mechanism of the device is expounded.The influence of roof rock strength and anchorage hole size on the stability of roof anchorage hole is preliminarily explored.(4)The processing of the roof anchorage hole quality degradation suppression device is completed,and the engineering application is carried out in the underground soft broken unstable coal seam combined with the differentiated anchor net cable support scheme.The results show that : after the application of the roof anchorage hole quality degradation suppression device,the construction quality of the roof bolt(cable)is fully guaranteed,and the control effect of the roadway roof strata is significantly improved.The design scheme is used to support the 12162 working face roadway with bolt-mesh-cable active support,and the deformation of surrounding rock of roadway is significantly reduced compared with the previous shed support.It shows that the support scheme is suitable for the engineering surrounding rock conditions of 12162 working face roadway in Shihao Mine.The active support technology of bolt-mesh-cable is helpful to improve the surrounding rock control of roadway in soft broken unstable coal seam.