Study And Application Of Water Flowing Fractured Zone About Paste Filling Mining

Paste filling mining is one of the most important mining methods in the "three-under" mining, and is an important measure to realize the pressure of coal resources under the safe water. At present, there are still many problems in studying on the development rule of water flowing fractured zone in paste filling mining under water body, which is worthy of further study. In this paper, theoretical analysis, numerical simulation,field test and other methods are used to study the movement and failure of overlying strata in paste filling mining. Also it analyzed the development rule of the water flowing fractured zone and obtained the calculation method of the water flowing fractured zone. The achievements are as follows:(1) The movement law of overlying strata in paste filling mining is studied by comparing the caving method. In the paste filling mining, the filling body plays a supporting role to the overlying rock, plays a limiting role to the subsidence and failure of overlying rock, and would change the original form of the movement of overlying strata. The damage of overlying strata usually only produces a small range of fracture zone, without caving zone. The roof has had no direct roof and basic roof.(2) On the basis of the study on the movement and failure law of overlying strata, based on the model of equivalent height, the geometric model is established through using the principle of two section arc to simplify the edge line of overburden subsidence basin, also the formula for calculating the development height of the water flowing fractured zone is derived based on the geometric relationship of the model.(3) Based on the equivalent mining height, the distribution of plastic zone is studied through numerical simulation in paste filling mining. And then it analyzes the failure law of overlying strata and the development height of water fractured zone caused by different equivalent mining height. What’s more,the formula of the relation between the equivalent mining height and the water flowing fractured zone is obtained by fitting the data.(4) Based on the general situation of the working face filling, the development height of the water flowing fractured zone is predicted by the mathematical model and numerical simulation formula, which is 4.37m, 4.51m.(5) The observation of the water flowing fractured zone of the working face is carried out by using the down-hole water injection, and through the analysis of the leakage rate of each hole, it is concluded that when the mining height is 2.2M, the maximum height of water flowing fractured zone is 4.16m.(6) Through the comparison analysis of the mathematical model formula, the numerical simulation fitting results and the measured results,there are some results: the prediction results of mathematical model formula and numerical simulation are slightly larger than the measured results, but the error is small, which three are closer. The results show that the mathematical model is accurate and reliable.