How to solve the problem of ground collapse in goaf of coal mine

Measures to prevent the collapse of coal mining face 1 It is a costly project to establish special funds to prevent the collapse of coal mining face. While actively striving for funds for the sustainable development of coal, local financial resources, urban construction funds and policy income are still the main channels for investment, so we should broaden channels, raise funds in various ways, and concentrate on the treatment of coal mining subsidence. First, actively strive for financial support from the state, provincial and municipal governments, actively strive for, make overall arrangements, centralize allocation and rational use in accordance with the principle of "three inputs" of the National Coal Sustainable Development Fund, and give investment support through investment subsidies and loan interest subsidies. , and focus on the governance of local coal mining subsidence areas; Second, we should collect land reclamation fees. According to the principle of "whoever destroys, who governs", the governance of mined-out areas will be included in the cost of coal production, and a certain proportion of land reclamation fees will be charged to coal enterprises that cause collapse hazards, and cultivated land reclamation fees, cultivated land occupation fees and paid use fees for new construction land will be bundled. Third, we must activate private funds. In accordance with the principle of "whoever governs benefits", give full play to social forces, extensively absorb idle funds from society, adopt the contract responsibility system, auction, lease and other forms, implement paid land use and paid governance, and invest in the construction of coal mining subsidence areas. Improving prevention and control technology to ensure the management of coal mining face is a complex ecological engineering and social engineering, which involves not only underground geological changes, but also factors such as above-ground fields, forests, roads, water and gas. Therefore, we must improve the content of science and technology and rely on advanced science and technology for scientific governance. First, carry out scientific planning, which should not only handle the relationship between short-term planning and long-term planning, but also consider the natural resources and the actual needs of social development in the subsidence area. Second, we should adjust measures to local conditions. According to the different types of subsidence land, different treatment methods are adopted, that is, appropriate agriculture means agriculture, appropriate forest means forest, appropriate fishing means fishing, and appropriate construction means construction. Where the subsidence is not deep or there is not much water, the land can be leveled and the farming conditions can be improved. Restore the landform; In the subsidence area with large area and deep water, aquaculture, tourism and leisure industries can be developed Through management, wasteland has been turned into treasure, and the effect of comprehensive management has been achieved. Third, we must adhere to the policy of giving priority to prevention and treating both the symptoms and the root causes. It is necessary to adopt advanced detection methods, strengthen the monitoring of mined-out areas, take effective measures to fill mined-out areas, minimize the subsidence area of mined-out areas, and achieve the goal of treating both the symptoms and the root causes. 3. Eliminate the influence of mining boundary. The place where underground mining has the most serious impact on the ground is the edge of the land subsidence basin, which is located on both sides of the mining boundary. Therefore, when the coal mining face is arranged under the building, the vertical working face should be long enough to make the surface fully exploited and the building located at the flat bottom of the active basin. In addition, when the mining face passes through the lower part of the building, the mining speed should be accelerated as much as possible, and the mining cannot be stopped, especially the residual pillars cannot be left. The law of surface movement shows that the permanent uneven subsidence and deformation of the surface are concentrated in the edge area of the surface subsidence basin. Every time there is a permanent mining boundary underground, there is an area with large deformation value on the surface. In order to minimize the harmful effects of mining on the protected buildings, it is required to realize full coal pillar mining, that is, to carry out large-scale comprehensive mining in the whole coal seam of the mine field to avoid the formation of permanent mining boundaries and the accumulation of deformation values of each coal seam in the coal seam range, so as to minimize the harmful effects on the protected buildings. Therefore, it is necessary to realize long face mining and slicing mining. Strengthening ecological restoration mainly refers to the technical treatment of pollution control in polluted areas, and it is also an important prerequisite for ecological restoration in coal mining subsidence areas. Mine development mainly pollutes the atmosphere, water body and land in the mining area, so the restoration and governance of the atmosphere, water body and land is the main task of ecological environment restoration (governance) in the mining area. About the traditional technical measures in this respect, the related research at home and abroad has been very rich. This paper focuses on the emerging "phytoremediation technology", which is the most economical, ecological and efficient ecological remediation technology so far. The so-called phytoremediation technology is a new pollution control technology that uses the absorption, volatilization, transformation and degradation mechanism of green plants and rhizosphere microorganisms to remove pollutants in the environment. According to the restoration function and characteristics of the restored plants, the types of phytoremediation technologies can be summarized as phytoabsorption remediation; Plant volatilization remediation method; Plant stable recovery method; Plant degradation and rhizosphere biodegradation. 5. Actively adopt the filling grouting construction technology. The filling grouting technology in goaf is based on grouting pump as the power source, injecting grout with filling cementation performance into goaf through grouting pipeline and grout stopping system, filling goaf, and controlling the movement of overlying strata and surface deformation. Filling grouting in goaf can be divided into full filling grouting and semi-filling grouting according to applicable conditions. Full-filling grouting is to use suitable and low-cost grouting materials to completely fill the cracks in goaf and overlying strata when the stability of overlying strata is high or the strength of strata itself is low. Semi-filling grouting is to fill the mined-out area effectively and control the movement of overlying strata and surface deformation at the same time.