Study On The Mechanism And The Prediction Model Of The Subsidence Caused By Rock Salt Solution Mining

The solution mining subsidence is great harmful which has a good many of specialties compared with alley mining subsidence, and the theories and methods of alley mining subsidence can't be used for it. So based on the specialties of it, the main research works are as follow: 1) The moving, distorting and breaking rules of overburden induced by mining are summarized, concluded and studied. The specialties and difficulties of solution mining subsidence are analyzed, which is the basis for further studies. 2) The moving, distorting and breaking rules of overburden, the evolution process of damage in overburden, the bedding influence and the size characteristics of broken rock are studied with model experiment for solution mining. 3) The numerical simulation software in existence has many shortages for mining subsidence. So the new FEM software for solution mining subsidence is exploited, which makes use full of the most new fruit of FEM theory. 4) The solution mining subsidence is studied with FEM numerical simulation. 6 mining models are built. The bedding influence, the angle influence, the faultage influence, the subsidence rules of single cavern, the subsidence rules of multi-cavern and the stacking principle are studied. 5) Based on the upper studies, using for reference the experience and method of alley mining subsidence, the 3D forecast model for solution mining subsidence is built, and the software is exploited for it. The results are as follow: 1) The solution mining is different from alley mining in mining direction, the shape of mined-out area, the mechanics character of mineral, the possibility of obligating jamb, water effecting the overburden, mining deep and mining height. It has more influence factors, it's more difficult to predict it, and it's more complex to control it. So the predict method of alley mining subsidence can't be used for it. 2) The rules of the solution mining subsidence are got. The evolution rules and equation of damage in overburden are got. 3) The bedding, faultage and angle effect severely on the subsidence. Because of the samdwich of terranes, it is different when every overburden distorts. 4) The size of broken terrane is connect to the rock strength. The major radius of influence can be got via mechanics parameters of terrane. 5) The Non-line contact unit is built, which is used to simulate the bedding, faultage and cranny. The damage variable and failure criterion of unit are used in the FEM software, which can analysis the process of rock damaging and breaking. It can simulate the broken rock via deleting the broken unit and adding elasticity load. 6) The stacking formula of surface distortion is got. The stacking principle is validated. The surface distortion of multi-cavern mining can be got via stacking the surface distortion of single cavern. 7) The mechanics parameters are imported in phenomenological theory, x and y direction major radius of influence and horizontal movement coefficient are imported. The new probability integral 3D model is built for subsidence, which is the same with the irregularly mined-out area and mining by all direction. The model improves effectively the traditional probability integral method. 8) The transfer 3D model one terrane by one terrane is brought forward, which improves effectively the precision when the traditional probability integral method is used for the sub critical extraction. 9) The dispersed formula is got, and the computing software is exploited with the new probability integral 3D model, which can predict expediently and effectively the subsidence of solution mining.