Research On Deformation Characteristics And Control Technology Of Surrounding Rock In Deep Large Cross Section Coal Road

The development of roadway support technology has a history of more than 150 years.It has mainly experienced the process of transition from passive support to active support.The support technology and technology are becoming more mature and stable.Among them,the complete set of roadway support with bolts and cables as the core Technology has now become the support trend of relatively complete coal mine roadways under some shallow geological conditions.Bolt and cable support has solved the problem due to its active reinforcement and mobilization of the bearing capacity of the surrounding rock and its good economy and support effectiveness.Supporting problems of various roadways under shallow geological conditions.However,with the increase of mining depth,many roadways supported by bolts and cables are affected by factors such as high stress,large cross-sections,soft and broken coal seams,complex structures,etc.,and strong mining pressures such as slabs,floor heaves,and roof collapses appear.It is a phenomenon that the safe use of the roadway cannot be guaranteed even after multiple roadway repairs,and higher requirements are put forward for the roadway support.This paper takes the 33192 deep large-section coal roadway in Zhaozhuang Coal Mine of Jincheng Coal Industry Group as the research background,and comprehensively adopts methods such as field investigation,theoretical analysis,numerical simulation and engineering test.Fragmentation,internal squeezing phenomenon,resulting in serious bending damage to the surface protection components,etc.,systematically studied the deformation characteristics and laws of deep large-section coal roadways and the grouting modification mechanism of the surrounding rock of deep large-section roadways,and proposed corresponding support schemes.The specific work is as follows:(1)Analyze the deformation characteristics of the surrounding rock of the 33192large-section coal roadway based on on-site observations.The roof of the local roadway is sinking and the coal bank is severely broken.The ordinary bolt and cable support method can no longer meet the demand.The deep,surrounding rock structure,mining face and roadway excavation and support methods are related,so the concept of high-strength support and multi-area coverage is proposed.(2)Based on the peep method and the surrounding rock loose circle test method,it is determined that the range of the coal siding fracture zone is within 0.5?2m,and the failure load and tensile strength of the rock mass sample are obtained through the physical and mechanical characteristics experiment of the surrounding rock,Poisson's ratio and other mechanical parameters of elastic modulus.(3)Through FLAC^3D numerical simulation,detailed analysis of anchor rod length,diameter,row spacing,and pre-tightening force are carried out,and the anchor rod support parameters are obtained according to the simulation results.The orthogonal test was used to optimize the design of each initial parameter,and the ranking of the influence degree of each factor was obtained by comparing the range.According to the orthogonal test result,the preliminary support parameters of the anchor rod were determined as follows:anchor rod length 2.4m;anchor rod diameter 24 mm;the row spacing between anchor rods is 900×900mm;the anchor rod pre-tightening force is 120 k N.(4)Analyze the grouting modification mechanism of the surrounding rock of the roadway theoretically,and conclude that grouting can improve the strength of the surrounding rock,reduce the loose circle of the surrounding rock of the roadway,and improve the effect of active support.The grouting mechanics model shows that the stability of the surrounding rock of the roadway can be achieved by increasing the thickness of the grouting bearing layer.(5)Through the FLAC^3D numerical simulation,compare the features of the roof full-bolt support,the side bolt+grouting and the surrounding rock under the original support,and obtain the feasibility of the support design.Through the simulation design,the surrounding rock of the roadway under the support Plastic zone,stress field distribution,roof and floor and two-side deformation of the surrounding rock change characteristics of the roadway,so as to analyze the deformation law of the 33192 large section coal roadway during the mining process.