Prevention of ground deformation disaster

To prevent the occurrence of ground deformation disasters, we can start from the following aspects:

1) mining is prohibited. Prohibition of mining is the most thorough and reliable method to deal with ground deformation. Because this method is contrary to mining behavior, it does not produce direct economic benefits and resources are not fully utilized. Therefore, it can only be used in individual sections where the predicted loss is large or the economic benefit of mining is lower than the cost of environmental restoration, such as railways, highways, large bridges, tunnels, reservoirs and underground coal seams where dense buildings are concentrated.

For Dayugou Coal Mine, Liangshuiquan Reservoir should be a forbidden mining area, and the mining boundary should keep a safe distance from the reservoir. In order to ensure the safety of the reservoir, the safety distance should be more than 2 times the width of the outer edge area. 2 times the outer edge around the reservoir boundary is a forbidden mining area. The forbidden mining area is outside the reservoir boundary197 ~ 225m. See Table 3.8 for the specific calculation of the safe distance and mining prohibition range of Liangshuiquan Reservoir, and see Figure 3.35 for the mining prohibition range.

Table 3.8 Calculation Table of Safe Distance of Liangshuiquan Reservoir

Figure 3.35 Prohibited mining scope of coal seam under Liangshuiquan Reservoir

2) Adopt special roof management methods. In order to reduce the roof deformation of goaf, pillar retaining method, filling method or roadway retaining support measures can be adopted. These methods are expensive, so they are not suitable for universal promotion. They are only used in the sections of Dayugou Coal Mine where the predicted loss is huge or the deformation severity is Grade I and II.

3) In the section where ground deformation has been formed, in order to prevent the loss of personnel and property from expanding, natural caving method is adopted to manage the Ⅰ and Ⅱ deformation sections of the roof, and the approval of new projects and their land use should be suspended, and the construction can be resumed only after two years of full mining.

4) Arrange residents' relocation in a timely and orderly manner. In order to reduce disaster losses and relocation costs, relocation work should focus on areas I and II with different deformation degrees, and make careful arrangements in advance. The relocation time can be determined according to the annual advancing speed of the outer edge zone of the goaf. The width of the outer edge zone of Dayugou Coal Mine is about 100 ~ 300m, and the annual migration progress can be controlled at about 100 ~ 300m. For residential buildings in middle and moderate areas of Grade III and IV, they can be reinforced according to specific conditions, and generally no immigration measures can be taken.

In short, no matter what preventive measures are taken, we must make a good demonstration in advance. The basis of demonstration should come from two aspects: first, risk assessment; The second is the evaluation of engineering importance and loss cost. On this basis, according to the specific situation of each mining area, make the choice of planning and measures.