| In China, coal energy’s distribution is largely imbalance, west and north area’s reserves are more than east and south areas. Due to the long time mining in eastern part, the mining environment is becoming worse: mining deeper, mining towards margin and hydrogeological conditions getting more complicated. For the reasons, the western development strategy in the long-term national energy development plan is implemented in order to meet the growing energy demand. For the different geological background between eastern and western China, geological and hydrogeological conditions exhibit different characteristics. Coupled with the impacts of environment and climate, Flood control problems of mining process have different requirements and technical difficulties. During western coal resources development, the new mine water damage and prevention issues need to be further studied and resolved.Hami Dananhu 5# coalmine is located in Gobi desert region, where the precipitation is scarce and the groundwater circulation is weak, the area is a relatively closed hydrogeological unit. The colliery mines Jurassic coal resources mainly, and the upper strata are Jurassic Xishanyao Formation aquifer system. In the exploration phase, the data shows they are weakly recharge aquifers, and will not cause too much difficulty to the building and mining project. But when they are exposed, the water flow is large and the quantity is stable, they recover quickly when stopping pumping, the water burst influences the project constantly. This thesis mainly deals with water damages in Hami Dananhu 5# coalmine, researching on the structure characterizes, hydrogeological characterizes and Jurassic weakly cemented aquifers’ characterizes, designing the project to prevent the water burst and control the groundwater’s threat in the first mining area, and simulating the water flow field evolution when dewatering. The main conclusions are as fellows:(1) On the basis of data collection and exploration tests, the thesis sums up that the study area is in a relatively closed hydrogeological unit and the aquifer medium are high-porosity and weak-cemented by analyzing the recharge-runoff-discharge conditions, aquifer medium conditions and high salinity groundwater chemical characteristics(17676.00mg/L);(2) By classifying and analyzing the different drainage projects underground, the thesis analyzes the factors affecting the flow of underground drainage holes, then designs indoor tests and producs that the water flow of a hole underground is gradually decay with the level’s reduce. Combined with examples and parameter optimization, the thesis produces the referred "Level-Flow" variation process of underground drainage holes which dewatering overlying aquifer in the study area;(3) According to the geological and hydrogeological conditions, the thesis establishes a groundwater numerical simulation model with FEFLOW software, and applies measured data for the model identification and parameter optimization(K=0.51m/d, μ*=0.0004), eventually gets a groundwater model meeting with the actual characteristics of the study area;(4) In order to ensure the safety mining in the first mining area, and according to the principle of combining ground dewatering project with underground, the thesis designes the dewatering prject for the roof aquifer in the first mining area(64 underground holes and 3 ground holes), then arranges the project according with the tunnel planning in the area;(5) For the characteristics of "variable level, variable flow, non-synchronous" during the dewatering process, the thesis generalizes the special superimposed dewatering progress reasonably, and simulates the flow field evolution when dewatering in the first mining area, the results appear that the roof aquifer can basically dewatering in period of stoping mining(200d), and the dewatering project achieves the desired objectives. |
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