Technology Of Soft And Fractured Roadway Support In Xishimen Iron Mine

Xishimen iron mine is well-known for its mining difficulty in metallurgical enterprises, and its magnetite deposit is of contact metasomatic skarn type. North Block of Xishimen iron mine has been in deep mining. With the deepening of mining, the ground pressure is growing. Deep rock is soft and fractured. It is different form shallow rock. Roadway supporting stability is one premise of safe and efficient production of underground mines, especially deep mines. Research of supporting technology of surrounding rock contribute to safety in production. For the research subject, the main contents which contains four parts are as following:(1) According to field geological lithology survey, the support form and destruction of roadway, point load experiment and classification of rock stability, it was found that only metal arch support of contractible type could not adopt to the change of rock stability. The main reason of destruction of soft and fractured roadway is that roadway was not timely and strength was not enough. Based on the rock stability and the characteristic of change, the combined support of anchors-gunite-web shoring and metal arch support of contractible type is suitable for the soft and fractured roadway.(2) It is conducted the orthogonal test in three factors and four levers of roadway combination support parameters by FLAC3D software and orthogonal test. Range analysis and analysis of variance verify the displacement of roadway, the displacement of boundary, the plastic zone volume. It is draw the conclusion that the best tunnel support parameter is the thickness of shotcrete is 150mm, the length of anchor is 2.5m, the distance of adjacent shape yieldable metal arch is 0.8m.(3) Aim at the roadway of skarn-type in Xishimen iron mine, the supporting design scheme recommends as follows:the thickness of shotcrete is 150mm, the type of shotcrete is C20. There are 9 anchor which is screw-thread steel with resin anchor erery row and the anchor is arranged at square. The length of anchor is 2.5m. The space grid is 900mm multiplied by 900mm. The material of shape yieldable metal arch is 20Mn-25 and the distance of adjacent metal arch is 0.8m. The legs weld steel plate square washer, whose size is 200mm×150mm×100mm.