Study On The Size Of Strip Coal Pillar Under The Dense Buildings And Above The High Confined Water

Though the coal resource is widely distributed in our country, it is becoming exhausted. Nonetheless, when the coal reserves of mines is reducing gradually, the amount of coal under buildings, water and railways is still great. With the increase of the mining depth, the exploration of the coal resources faces negative effects from that such as water, etc. Therefore, for a better development and utilization of existing resources, it is the time to liberate the coal resources under buildings and threatened by water.Based on the main problems about that the coal is under the buildings and the mining is threatened by water, the basic situation and the hydrological geology characteristics of working area 1160 of DaiZhuang coal mine of ZiBo mining group, this article analyzes the feasibility and the importance of mining exploitation. With the theoretical formula and predicting the surface subsidence, it analyzes the size of strip mining under buildings. Second, with the mechanism of water inrush through bottom, it researches the stress of the floor. With the "down three zones" theory the thesis analyzes the water-borne resistance characters of bottom and the depth of floor destroyed, combining with the actual hydrogeology conditions of the working area, and obtains the thickness and characters of the water-resisting layer who lays the foundation for analyzing the reasonable mining size above confined water. In the end, according to the research method of rock mass hydraulics, it regards bottom plate as mechanics rock beam to analyze the relationship between confined water of floor and the mining width, then uses floor beams theory to calculate the safe retaining width of strip mining above confined water. In order to choose a better scheme about strip mining to meet the two conditions, through numerical simulation software, according to different mining schemes, this article makes dynamic simulation from various aspects, such as pillar stability, surface subsidence, floor plastic damage and so on, to analyze the plastic damage situation of different strip mining coal pillars, the surface vertical displacement situation, and the difference between the damage, the stress, and the displacement, then ultimately it confirms a reasonable strip size.In the end, according to the results of theoretical analysis in the text about reasonable mining size of strip mining both under buildings and above confined water, combining with the numerical simulation conclusion, taking the safety of buildings and mining above confined water as the prerequisite, fully considering the mining rate, then it formulates a rational strip mining scheme to liberate the influenced coal resources maximumly. The comprehensive analytical method to confirm the parameters has high reliability and good application value, so the dissertation has very important reference value to the other mining areas which are in similar geological and mining conditions.