Study On Firm Technique Of Preliminary Mining Engineering In Gongchangling Underground Mine

It means to underground mine that the stability to the excavation and support of the roadway is the precondition for the safe production in mine. Because of the descending of the roadway depth and the influence of the complex condition of the geology, it's more difficult to maintain the roadways'stability that influences the safe production in the mine seriously. Gongchangling underground mine is metamorphosed sedimentary magnet deposit, there is a great deal of chlorite schist with developed joints and faults. When tunneling work pass through these regions, the tunnel destructed seriously, and the project of support was damaged over and over again, which seriously affected the progress of follow-up works, a lot of high value tunnel which can be restored were destructed in a very short time. So, study on firm techniques of instable terrane has great meaning of Gongchangling underground mine's safety and production.This article start with analyzing geology of that mine, then clarify the definition, classification and the basic characteristics of the soft rock, and made comprehensive analysis to factors which affect stability of soft rock tunnel, mechanics and deformation mechanism of soft rock tunnel, also introduce basic theories of support and some effective support ways for Gongchangling underground mine, and builds up the finite element model of-280m level soft rock tunnel by the software of FLAC3D, optimize the section shape of tunnel, it simulate the condition of the stress and the strain after the exaction, it also analyzes the deformation mechanism of the surrounding rock. After that, the paper simulates the bolt support, shotcrete support and bolt and shotcret support, analyzes the effect of support for each method, and use the results to bring forward the supporting scheme:the section shape of tunnel is vertical wall semicircle arched; using simple smooth blasting technology when tunneling; support must be keep pace with working face; there are 13 anchor arms every row, and the space length is 0.8m; shot the flexible concrete with steel fiber, the depth is 50mm., some extremely broken rock region should lay metal mesh.