Surrounding Rock Control Technology Of Large Vertical High Roadway With Pre-dug Composite Roof

The effect of bolt-strip-mesh-anchor support in the roadway with composite roofin Zhaizhen coal mine is not fine, what’s more, there are serious problems in this kindof support. From one hand, the speed of excavating is slow, and the rate of roadwayroof renovation is high, which leads to a high support cost in the end; On the otherhand, the security of roof support is poor, the overall deformation of roof is large, partof the roof caves heavily, the abnormal underground pressure behaves significantly.Through analyzing of the failure of the support of roadway with composite roof, thesurrounding rock control technology of large vertical high roadway with pre-dugcomposite roof is put forward in this paper. This paper adopts the methods oftheoretical analysis and numerical simulation to fix the supporting parameters ofbolting and anchor rope in large vertical high roadway with pre-dug composite roof,combined the characteristics of the section of roadway and the surrounding rock stress,the advance hydraulic supporter of large vertical high roadway with pre-dugcomposite roof is designed, as well as the project application is carried out, the mainachievements are as follows:(1) The ultimate strength and strata cohesive force of composite roof of Zhaizhencoal mine are low. In the dual role by ground pressure and mining pressure, the coalrock soft roof broken, caved and rock plastic area expanded unceasingly, caused therock of anchoring section gradually deformation, delamination, and the anchor draggradually reduce. The weak composite roof loose swelling form vertical load to thelower strata, eventually led to the failure of bolt and cable anchor support androadway roof appear larger sink.(2) The middle roadway of3405E in Zhaizhen coal mine adopted thebolt-strip-mesh-anchor support in large vertical high roadway with pre-dug compositeroof, by theoretical analysis and numerical simulation, designs the supportingparameters of bolting and anchor rope.(3) Reasonable advancing support distance within the3405E working face inZhaizhen coal mine is made by analyzing. Combining with the cross section ofroadway, design the type of eight columns section with the top beam supportinghydraulic supporter in advance, and calculate the of the minimum support strength,setting load and working resistance.(4) Project application of the surrounding rock control technology with large vertical high roadway with pre-dug composite roof is adopted in the3405E middleroadway in Zhaizhen coal mine. Monitoring result shows a small deformation inroadway and the section of the roadway meets the requirements.