Research On Stress Field And Engineering Stability Of The Second Mine Block In The Jinchuan Mine

In the recent years, with the increasing excavation depth and the truth of double-level mining, drifts were strongly deformed and severely damaged in the second mine block in the Jinchuan mine. Some drifts couldn't be used normally even being repaired for many times. The geostatic emergence is very obvious. The crevasses in the surface have been occurred and enlarged quickly. Sometimes there is caving in the stope and the filling bodies. It is necessary to study on the rock mechanics problems in the deep engineering area. The stress is one of the most important factors to affect the underground engineering. Engineering excavation will result in re-distribution of the stress in the surrounding rock. So it is very important to study the stress condition in the deep mine area and the relationship between the stress state and the underground engineering.This paper relies on the technological project of the Jinchuan Company"Study on the Stress Field and the Rock Mechanics in Jinchuan mine". The work is mainly in the second mine block. We have done a lot of work such as engineering investigation, the characteristic of rock mechanics and the tectonic stress field in the second mine block. We have also done the indoor experiment and numerical simulation. Through those works, we grasp the stress distribution in the mining Area. On the basis of this knowledge, combining the underground project reality we analyze the stability of the key project.The main works which we have done are drawn as follows:1. Systematically collect and analyze the data of the stress and the rock mechanics which were done by the predecessors.2. Investigate and analyze the engineering geologic characteristic in the mining area.3. Stress measurements were made at different structural position and depths and in different rock. Base on the results of stress measurements to study on the characteristics of the action of the stress in the mining area. And the stress characteristics of in deep level compare with in shallow level in the mining area.4. Study on the finite element simulation of the stress field of the mining area.5. Research on the tri-dimensional finite element simulation of the stability of the key project.Based on the above works some conclusions are drawn as follows:1. Based on the results of the stress measurement, to construct the stress field by the numerical simulation in the deep level in the mining area.2. The results of the stress measurement indicate that characteristics of the action of the stress in the deep level of the second mine block. And it can also be seen that the characteristics of the action of the stress difference between the in the deep and in the shallow. The results of the stress measurement well coincides with the actual deformation and damage in the project. The results offer the reliable scientific foundation for the design and the construction of the underground project.3. On the basis of the stress field which is founded in this paper, through the survey and the monitoring of the deformation of the key drifts, combining the engineering geological investigation and the software ANSYS to do the tri-dimensional simulation analysis for the chosen sectors to analyze the main reasons of deformation and damage of the drift. These works is important for the upgrading of design and the stability of the project in the deep level in the mining area .4. Base on the results of the stress measurement combining the engineering geological condition and the finite element tri-dimensional simulating to elementary study the stability problems of the horizontal and the vertical jambs. These simulation analyses establish six digging schemes. The results of simulation indicate that the stress changes during the jambs excavation procedure. Also the six schemes compare with each other to determine the preferred scheme. The elementary judgment of the stability of the jambs during the excavation procedure and suggestions for the jambs excavation are made nowadays.