Study On Surrounding Rock Stability From Soft Rock Tunnel Advance Support Under The Excavation Disturbance

Soft rock roadway support has been a problem in the process of mining, soft rock roadway for different geological conditions require different means of support.Supporting the use of advanced technology for soft rock roadway support effective reinforcement of surrounding rock, country rock mining process to ensure stability, to reduce the probability of accidents, advanced technical support during the mining of soft rock tunnel can achieve good support effect.Taking Guizhou Jinfeng Gold Mine underground mine soft rock roadway issues as background, using theoretical analysis, numerical simulation and field test, disturbance from mining on soft rock tunnel of surrounding rock stability forepoling impact on in-depth research, Presented soft rock roadway overall support program for the specific circumstances of the Jinfeng Gold Mine underground mines and their further optimization.The main research contents are as follows:(1) analyze and summarize instability from mining disturbance factors in soft rock roadway, using Griffith strength theory and Mohr Coulomb guidelines for stability of surrounding rock of soft rock roadway under mining disturbance, analysis the instability on the form of destruction in soft rock roadway of Jinfeng gold mine.(2) To the establishment of Jinfeng gold mine for the underground mine soft rock excavation process numerical model, using simulation of grouting anchor FLAC3 D advance support on surrounding rock stability of soft rock excavation process, and comparative study of different inclinations grouting anchor advance support programs.The simulation results show that: 60 °grout bolting advance support program can improve the stability of soft rock tunnel excavation process, to ensure the safety of the tunnel excavation process,provide technical support for the Jinfeng Gold Mine underground mine production safety.(3) For the Jinfeng Gold Mine underground mine soft rock excavation process proposed advance support and bolting and shotcreting combined support program, and joint support program to optimize support to determine the final program. Joint support program: continuous tunnel before excavation after excavation 5m 60 ° grout bolting advance support, followed by C30 concrete were reinforced shotcrete, establish last 3 rows of 7 bolts, 21 in toatl resin anchor anchoring lever.Through theoretical analysis and field tests show that the final joint support scheme can meet the reduction requirements under the premise of the stability of surrounding rock excavation work cycle, improve mining efficiency, reduce support costs, reduce waste of resources.