Study On The Crushing Theory And Support Technology Of Soft Strata In Jinchuan No.2Mining District

Deformation failure and supporting of deep soft roadway excavation is knotty problem in the field of rock mechanics all the time, especially under complex geological conditions. Since rock mechanics research started, deep roadway of rock mechanics problem has been focused by the researchers, but environment of deep roadway is very complex, what’ s more, various kinds of questions coupled together, the most typical characteristic is "three highs and one disturbance". Despite research of deep soft rock roadway has been no breakthrough progress, but also made some achievements.Jinchuan is typical deep ore bodies in our country, with the shallow resources reduce and even dry up, corresponding, its mining depth increase gradually, the problems of surrounding rock stress is more and more outstanding. In recent years, the safety in mine production and economic benefits has been influenced by deformation, destruction and supporting of roadway; the traditional support means, such as ordinary bolt support, U shaped steel arch support and bolting nets et, has not been able to keep the deep roadway stability. When mining depth below1000m, the mine development construction are hard to continue, rapid, long duration and large deformation make the excavation difficult to continue, which had ever seen in history of Jinchuan No.2mining; some roadway haven’t put into use, but repair work have started already, which is urgent to solve. According to "Jinchuan No.2mining deep roadway rock mechanics problem", following aspects of research has been carried on:(1) According to the geological reports, we made a thorough investigation for blurred district. Thinking that geology of Jinchuan mine is complicated and uniaxial strength of rock is high strength, but strength of rock mass is low, which show obvious rheological property, according with the characteristics of the soft rock.(2) Rock mechanics parameters had been determined accurately by in-house petrophysical experimental for a lot of samples. Mechanism of deep soft rock fracture about Jinchuan No.2mine had been brought forward based on the soften path of soft rock and the plastic fractured region theory, which conduce to research rock mechanics and support of deep soft roadway.(3) Following the research in this paper, the main reason of deformation failure in the deep roadway is well-developed faults and joints of surrounding rock. Because of great ground stress, horizontal tectonic stress and mining movement, the rock mass present crack-expansion creep characteristic, the main deformation manifested as slip,dislocation and crack expansion,etc.(4) Using finite difference software FLAC3D to simulate deformation and support of the surrounding rock, based on its result, different support scheme had been put forward, then discussing the advantages and disadvantages of different support and optimized them.(5) With results of research, the shotcreting, bolting and cable combination supporting can effectively restrain roadway deformation development, maintain its stability. As well as some understanding and suggestion has been propounded for the deep soft roadway support.