Large Deformation Mechanism And Control Technology Of Coal Roadway With High In-situ Stress

With the continuous development of China's industry,there is still a great demand for coal resources.The exploitation of shallow coal resources in eastern China is coming to an end,deep coal mining is the focus of current and future development.However,deep mining is also faced with many difficult problems.For example,the high level stress in the deep causes the strong ore pressure,which is one of the difficult problems in the deep mining of coal.Under the jurisdiction of Shandong Yulong group co.,LTD.,Yineng coal mine 13 belt haulage roadway due to the influence of high level stress,the roadway surrounding rock appeared large deformation,many times of repair,seriously affecting the normal production of Yineng coal mine.In this paper,13 belt haulage roadway in Yineng coal mine is taken as the engineering background.Through the comprehensive research methods of theoretical analysis,numerical simulation,laboratory experiment and field monitoring,this paper analyzes the stability of the surrounding rock of the roadway with 13 belt haulage roadway,puts forward the surrounding rock control technology and scheme applicable to the roadway with 13 belt haulage roadway,and carries out the field application and data monitoring of the proposed support scheme,and obtains the following main research results:(1)Through on-site in-situ stress test on the 13 belt haulage roadway,the test results are as follows:the maximum horizontal principal stress is 25.01 MPa,the minimum horizontal principal stress is 12.56MPa,and the direction of the horizontal stress is nearly perpendicular to the roadway direction of the13 belt haulage roadway.Drilling into 13 belt through the alleys finally concluded that:0.6 m or so surrounding rock of roadway roof breakage phenomenon obviously,within the scope of 0.6 m to 1.5 m much delamination and fracture,1.5 m above the surrounding rock is complete,no broken and fracture;Two for 1.6 m or so of roadway surrounding rock breakage phenomenon is obvious,many within the scope of 1.6 m to 5.0 m abscission layer and fracture.(2)The influence of the lateral pressure coefficient on the plastic zone of the two sides of the 13 belt haulage roadway is studied by theoretical analysis.The results show that the plastic zone of the two sides of the 13 belt haulage roadway is proportional to its lateral pressure coefficient.The influence of lateral pressure coefficient on the stability of surrounding rock of 13 belt haulage roadway is studied by numerical simulation.In particular,the displacement of the two sides seriously affects the normal use of the roadway.Therefore,the key point of surrounding rock control of 13 belt haulage roadway is to control the deformation of two sides of roadway.(3)Based on the analysis of the stability of surrounding rock of 13 belt roadway,the joint support method of bolt and anchor cable is proposed to solve the problem of large deformation of the main part of 13 belt haulage roadway.The analysis of the supporting mechanism of bolt and anchor cable respectively,according to the internal rupture partition of drilling into rock and numerical simulation of two range of plastic zone,find help from the length of the anchor rod anchor to the stability of rock,which can effectively control the deformation of roadway help department question,proposed for department adopts bolt+anchor rope combined support method,and analyses the different length of anchor rod and anchor rope comparison,the reasonable bolt+cable combination parameters are confirmed as 8.0m bolt and 2.4m bolt.(4)The roadway in the test section of the 13 belt haulage roadway is supported by the optimized design scheme and the surface displacement,internal displacement and stress of the 13 belt roadway are monitored on site.The monitoring results show that:The optimization scheme can effectively control the surrounding rock of the 13 belt haulage roadway,greatly reduce the condition of the caving roof.After 30 days of monitoring,the deformation of the roadway is basically stable,with the two sides moving 412mm and the roof and floor moving 173mm.By analyzing the stress curve of bolt cable in 13 belt roadway,it can be clearly found that all of them can provide large anchorage force.