Study On Construction Of Goaf Underground Reservoir Of Gob Side Entry Retaining Roadway

The purpose of this paper is to replace the 30m pillar with the retaining wall, so as to build an underground reservoir in the goaf. At the end of the mining, the caving space of the mined area is regarded as the storage space,so as to analyze the feasibility of building the underground reservoir, then the construction theory and the technical system of the underground reservoir will be developed. Though the summary of the concept?classification and characteristics of the goaf underground reservoir, construction process and operation system will be founded, which determine the goaf underground reservoir as an effective way which can protect water resources.Through the effective separation of the retaining wall, a confined space is formed. When the face is extracted, the produced water can be stored in the goaf, so as to achieve the effect way of water saving and coal mining. Based on the roadway,through the twice development of the retaining wall, which increase the role of the retaining wall. Compared the way which using of the coal pillar as the wall to construct the underground reservoir,improving the coal recovery rate,which has a ecological and economic benefits.In the process of next level mining, through water diversion system which can prevent the crack coalescence and water inrush accident. There is a "empty - real -empty" structure in the goaf space. Through the convection of the mine water,and the mine water could be purified.Using UDEC and FLAC 3D to simulate the overlying strata subsidence movement, which conclude the law water storage space distribution of underground reservoir is that falling water storage space which is a loose distribution in the middlezone and around the outside of the ring type O compaction. The water storage in the fracture zone is distributed in the gap between the separation layer and the vertical rock mass. The spatial distribution of water storage in the caving zone is in the gap of the collapsed rock. Through establishing of the mathematical model of underground reservoir, the storage capacity can be calculated. Based on multi factor, the model of underground reservoir can be established, and the mechanical parameters of retaining wall along gob side entry could be set.The above research provide a systematic theory for the construction of underground reservoir in coal mining area, especially for the protection of water resources in arid and semi-arid areas of Western China.