Study On Surrounding Rock Deformation Mechanism And Control Technology For Large Cross Section Cavern

It is a difficult subject that the researching of large section cavern surrounding rock deformation mechanism and control technique, under complicated geological conditions in the underground engineering. With the influence of the complex factors, such as, the large cavern section size,the poor surrounding rock conditions, significant tectonic stress and complex mining stress field, make the large section cave have more special and complex surrounding rock deformation and failure rules compared with the traditional ones. A series of serious surrounding rock deformation instability problems are caused during the cavern excavation, and the conventional supporting methods can’t satisfy the requirement.Taking shanxi LuAn wangzhuang coal mine+540m level underground large section support installing cavern as the research background, researching the large section cavern surrounding rock deformation mechanism and control technique, from the deformation and failure characteristic, stability control principle, support technology scheme and other aspects, by the methods of material collection, theoretical analysis, numerical simulation and field monitoring. The main results are as follows:(1) Putting forward the surrounding rock plastic deformation calculation formula of large section cavern, and the size effect of the surrounding rock plastic deformation of large section cavern is analyzed. FLAC3D numerical model is established, analyzing the surrounding rock deformation regularity, stress and the plastic zone distribution characteristics of large section cavern, influenced by the factors of cavern sectional area, surrounding rock properties, tectonic stress, adjacent cavern arrangement distance. To reveal the large section cavern surrounding rock deformation mechanism.(2) Surrounding rock deformation control of large section cavern excavation were studied according to the deformation characteristics of large section cavern surrounding rock, firstly, numerical simulation analysis three method in common use of (double side drift method、Center Diaphragm、positive step method), Comparison of three different excavation methods of large section cavern surrounding rock stress、 deformation and failure characteristics, it shows that the positive step method can better control the stability of surrounding rock of cavern.Then, Through a variety of surrounding rock control scheme comparison and analysis, put forward the combined supporting technology, including "Lengthen bolt anchor cable+Grouted cable bolts+Floor long anchor cable".This scheme can make the cavern surrounding rock form of multi-level bearing ring, in improving the mechanical properties of the surrounding rock while exploiting the self-bearing capacity of rock, well to ensure the stability of surrounding rock cavern.(3) The proposed control scheme of surrounding rock was applied to wangzhuang coal mine large section support installing cavern.Analyzing the result of the surrounding rock deformation monitoring, it shows that after using this scheme, the stability of surrounding rock is greatly improved.