Research On High Strength Support And Control Technology Of Soft Rock Roadway

The shallow rock mass has brittle characteristics,which may be transformed into plasticity or impact damage as it enters the deep,accompanied by strong time effect,showing obvious rheology,coal rock mass joints,crack opening and new cracks.,causing a large area to collapse.During the mining and excavation process of coal roadway,the rock layer encounters soft and broken surrounding rock,and the stability of the roadway has become an urgent problem facing underground mining.At present,most coal mines use traditional anchors and anchor cables for special geological rock formations.The limitations of the traditional anchor and anchor cable anchoring characteristics are not taken into account,and the deformation of the surrounding rock is not effectively controlled.This paper makes a qualitative analysis of the lithology and rock formation occurrence of the surrounding rock in the 2111 roadway of zengzifang mine by sampling the surrounding rock through field investigation.In order to control the deformation of surrounding rock,a new supporting scheme is designed for this soft rock roadway,and the relationship between the strength of high-strength bolt and ordinary bolt and their elongation is analyzed.A high pretension device is put forward to make the bolt obtain more prestress during installation.Simulates the design of embedded pallet,and analyzes the stress condition by comparing the pallet.The roadway is supported by high-strength anchoring and grouting,that is,the combination of hollow grouting anchor cable anchoring+high-strength anchor rod+pretension anchor cable+net.Then the support simulation of 2111 roadway was carried out by FLAC^3D software.Finally,through 120d field monitoring,the two sides'displacement,roof subsidence and anchor bolt and cable stress were obtained.This paper has obtained the following main results:?1?Through the analysis of the previous rock structure data provided by the roadway and the determination results of laboratory rock physics and mechanics,it is found that there are many pore cracks inside and on the surface of sandstone,which is consistent with the results obtained by indoor acoustic emission test.In other words,the number of acoustic emission rings increases rapidly in the elastic stage,reflecting that the roadway belongs to soft and broken surrounding rock.?2?By comparing the strength of high-strength bolt with that of ordinary bolt,the comprehensive performance of high-strength BHR600 bolt is excellent,and it has a high safety coefficient when used to control the deformation of roadway surrounding rock.The hollow anchor cable is used to support grouting so that the anchor cable can be fully anchored and the deformation of roadway surrounding rock can be effectively controlled.?3?A high pretension device is put forward to make the bolt obtain more prestress during installation.?4?Simulation design of embedded tray,through the comparison found that the embedded structure of the tray stress effect is better.?5?FLAC³DD model was used to analyze the roadway displacement change,the distribution characteristics of surrounding rock plastic zone and the mechanical characteristics of supporting structure.?6?Through field monitoring,roof separation,convergent deformation and force of bolt?cable?of roadway surrounding rock are collected and recorded,which proves that this design scheme can effectively control the deformation of soft and broken surrounding rock.The paper has 79 figures,12 tables,and 52 references.