Research On Support Technique Of Deep Soft Rock Mining Roadway In Qingyun Coal Mine

With the increase of coal mining depth in China,a series of support problems have also followed.The shallow mine support method has completely failed to maintain the surrounding rock deformation of soft rock roadway under deep well conditions.At present,the support methods and theories for deep wells have become the research direction of many scholars..Since the Qingyun Coal Mine of Shanxi Jiexiu Yiqi Qingyun Coal Industry Co.,Ltd.has been put into production,due to the geological conditions such as deep roadway depth and weak surrounding rock,it has been facing the problem of serious deformation of the surrounding rock of the roadway,how to carry out its deformation in the form of support.Effective control has become an urgent problem for Qingyun Coal Mine.Based on the support problem of mining roadway in 020202 working face of Qingyun Coal Mine,this paper uses theoretical analysis,numerical simulation and engineering practice as the means to study the support problem of deep soft rock mining roadway.The specific work is as follows:(1)According to the field observation and theoretical analysis,the deformation characteristics and influencing factors of surrounding rock of020202 track roadway are analyzed.It is considered that the surrounding rock deformation of 020202 track roadway has wide damage range,large deformation,and failure of anchor and its components.The characteristics of the roadway deformation are mainly affected by factors such as stress environment,surrounding rock strength,surrounding rock structure,working face mining and support methods.Combined with the problem of roadway support,the concept of improving the support strength,increasing the support depth and adjusting the support density is proposed.(2)Based on the theory of surrounding rock loose circle,the deformation mechanism of roadway surrounding rock is analyzed,and the radius expression of the surrounding rock relaxation zone,rupture zone and plastic zone of the roadway is derived based on elastoplastic mechanics.The actual geological conditions of the 020202 track roadway are calculated.The radius of the surrounding rock relaxation zone is 4.8m,the radius of the rupture zone is 3.83m,and the radius of the plastic zone is 8.12m.(3)Theoretically analyzed the joint support mechanism of anchor bolt,anchor cable and anchor cable,and obtained the force analytical formula of bolt and its components through mechanical analysis;(4)Through the FLAC~3DD numerical simulation,the bolt support length,anchor diameter,bolt spacing,bolt preload,bolt type and pallet type are analyzed in detail,and preliminary support is determined according to the analysis results.Design Parameters.The initial design parameters were optimized by orthogonal test.The influence degree of each factor was obtained by comparing the extremes.The final support parameters were determined according to the orthogonal test results:anchor length 3m;anchor diameter 20mm;anchor The distance between poles is 800×800 mm;the pre-tightening force of anchor is 100 kN;the length of anchor cable is 6.2 m;the diameter of anchor cable is 21.8 mm;the pre-tightening force of anchor cable is 220 kN.(5)Comparing the characteristics of surrounding rock under unsupported,original support and design support conditions by numerical simulation,verifying the feasibility of support design,and further analyzing the variation characteristics of roadway surrounding rock under simulation design support scheme The deformation law during the excavation and mining process.(6)Verify and monitor the support according to the engineering practice,monitor the deformation law and supplement the support plan.The results of numerical simulation and on-site monitoring show that the design support scheme effectively controls the deformation of the surrounding rock,greatly reducing the cost of repair,and the economic effect is good.