The Research Of Strip Mining With The Thick Loess Under The Village

In the western region with the thick loess, the damage of the ground surface induced by mining has itself characters. For a long time, we applied widely the strip mining to reduce the ground surface movement and deformation and to protect the buildings and the facilities. In according with this problem, the thesis predicts the ground surface movement and deformation with the numerical simulation, and determines the reasonable mining scheme Whether the result of predicting the ground surface movement and deformation with the numerical simulation is precise depends on selecting the appropriate theory model, the method of calculation and determining the rock mechanics parameter. Based on the result of the observation of the ground surface movement and deformation in BaiShui river in PuBai mine area, this thesis apply anti numerical simulation with FLAC3D to fit the rock mechanics parameter and determine the numerical simulation of theory model and rock mechanics parameter to predict the ground surface movement and deformation in the area of the same kind geology Analyzing the stability of coal pillar is one of the key problems. For a long time the stability analysis of the coal pillar concentrates on the viewpoint of static. Suffering the influence of the mining, the strength of the coal pillar has to lower. This mechanics characteristic can be used the rule of Hoek-Brown to express accurately. But FLAC3d has not definite the Hoek-Brown theory model. This thesis deduce out the relationship of rock mechanics parameter between Hoek-Brown rule and Mohr-Coulomb rule. Applying the Hoek-Brown rule to determine the friction angle and the cohesion, it need the value of σ3, but during the calculating the value of σ3 is a variable, this use the internal function in FLAC3D to transform the property of the material with the value of σ3. On the other hand, the stability of the coal pillar also has something to do with the opposite moving direction of the coal bed roof and the coal bed floor. During the period of the mining the coal bed roof has the tendency moving to the center of the goaf, thus come into being the shear force in the top coal pillar, so the different stress state come into existence in the top zone. Between the coal pillar and the coal bed floor, the comparatively moving direction is reverse of the moving direction, which between the coal pillar and the coal bed roof, so in the bottom and top of the coal pillar the zone of the different stress state are not symmetry. This thesis simulates the dynamical stability of the coal pillar according to the scheme of XiGu dip strip mining. From the result we can arrive at a conclusion that coal pillar has the dynamical and long-time stability.The mining system, the combination system of covered rock and the system of protecting building are a whole related system to reduce the mining damage. Especially the mining damage caused by the key stratum control in the western region with the thick loess exerts the momentous function. This thesis simply simulates analyzes the function of the key stratum with FLAC3D under the condition of XiGu geology Anti simulating the result of the observation in BAISHUI river to determine the proper theory model and the rock mechanics parameter, simulate and analyze the stability of the coal pillar and the ground surface movement and deformation in the whole basin with FLAC3D. The result is validated by the result of the equivalent material model test and the influencing function. The last scheme, namely dip various and harmonious strip mining, is determined.