Study on optimized support parameters of mine roadway in broken surrounding rock of deep thick and unconsolidated strata

In order to solve a support problem of a mine roadway in broken surrounding rock of a deep thick and unconsolidated strata in Chensilou Mine,on basis of s tndying the geological condition and support method of- 720 m auxiliary level air returning roadway,a numerical simulation,theoretical analysis,site observation and other m ethod were applied to a study on the optimization of bolt anchorage length,pretension, bolt length,space and raw distance between the bolts and parameters of the mine roa dway support. An industrial trial was conducted in the mine. The results showed that in the- 720 m auxiliary level air returning roadway,the anchorage length of the bolt in t he rational support parameters should be 1 13 of the bolt length at least,the pretension should be 50% ~ 70% of the bolt loading limit,the bolt length should be 2. 5 m,the sp ace and raw distance between the bolts should be0.7 m x 0. 7m. With the implementation,the optimized plan could effectively control the deformation of the surrounding「 ock in the air returning roadway and reached the expected target.