Excavation And Supporting Technology Of Roadway At High Stress Areas In Wafangzi Manganese Mine

The surrounding rock of roadway in Wafangzi manganese mine is batt, which belongs to a very thin layer of rock mass. Also ore rock joint development is broken. The seam and rock strata are rich in joint and very broken. In the process of mining, the development roads have serious ground pressure. With roadway floor heaved, the two roadway walls crowded inside and roof fallen, it is a huge work to support the entry. Although the bolt and metallic frame, and other supporting measures have been taken, flat haulage roadway was crushed and the roof of connection roadway fell before mining chamber stopping was finished. In the tenth flat, the ground pressure became bigger. With the big caving of flat haulage roadway after rerouted severe times, the development work is hard to finish. The ground pressure problem has become major technical problem that restrict production in Wafangzi manganese mining. The paper based on the method of combining field research and numerical simulation, the method of controlling thin roadways’ ground pressure in thin layered clay shale.Firstly, the occurrence, the feature of pressure appearance and the destruction of roadway of the Wafangzi manganese mining have been investigated systematically. Investigation of the structural surface and determination of point load strength for the roadway surrounding was taken, so that the degree of stability has been finished. It concluded that the stability of the surrounding rock of roadway in Wafangzi manganese mine are from medium to very unstable and most of them are unstable. Secondly, according to the process and result of destruction, the reason of destruction has been analyzed, what’s more, the roadway damage form has been concluding:Rib spalling-floor heaving-roof sagging and roof caving. The mechanical model of roof strata destruction and picking and the process of destruction have been simulated by FLAC3D. According to the result, stress state of surrounding rock as the roadway destructed was analyzed. With the combination of theoretical calculation and field investigation measure, the feature of the discordance of surrounding rock deformation has been proposed.Finally, the self-stability span of the roadway is 2.3 meters and the height of the tunnel roof caving arch is 2.7 meters have been determined by means of the field measurement. So designed the cross-section shape of the roadway whose roof is basket-handle arch and the floor is oval arch. Finally we use the scheme of full section of spray anchor net supporting scheme. FLAC3D software is adopted to analyze the distribution characteristics of the variation of the stress and displacement after the roadway excavation. And the reasonable parameters of spray the anchor net supporting is determined...