| In recent years,while the massive mining of coal resources ensures the rapid development of my country’s social economy,coal mining has also caused a series of problems such as surface subsidence,loss of arable land,and environmental damage in mining areas,and the subsidence area caused by underground coal mining has increased year by year.Some coal resource-based coal mining subsidence area is more than 10% of the total urban area,especially for coal resource-based cities in high-water-level mining areas in eastern my country.The coal mining subsidence area is easily formed into a large-scale permanent water accumulation area due to the high underground water level,changing the original ecosystem,has brought huge harm to the urban ecological environment and human settlements,causing a series of problems such as man-land conflict.In order to comprehensively control the coal mining subsidence area in the city,repair its original ecosystem,and then solve the social problems faced by residents near the subsidence area.This paper takes the Huaibei mining area as the research area,relying on the Huaibei City Lvjin Lake comprehensive treatment project,gives the evaluation method of water resources in the coal mining subsidence area in the city,studied the construction technology of the ecological restoration project in the coal mining subsidence area in the city,explored the comprehensive management and sustainable operation mode of the coal mining subsidence area in the city,the specific research contents and results are as follows:(1)Taking the coal mining subsidence area of Lvjin Lake in Huaibei as the research base,combined with socio-economic conditions,geological mining conditions and ecological environmental status,the surface subsidence and environmental damage characteristics of the high-diving coal mining subsidence area were analyzed.The main manifestations are long subsidence period,large subsidence coefficient,wide surface water area,serious damage to the ecosystem,etc.It puts forward new challenges for ecological restoration under the conditions of spatial intersection of new city construction and subsidence area.(2)Through field sampling tests,carried out the evaluation of water resources in the subsidence area,through the analysis of water quality and hydrogeochemical characteristics,it is concluded that the quality of surface water and shallow groundwater has reached the quality of class III or above,the whole belongs to the water with higher mineralization degree;Sampling and testing the sediment,analyzing the pollution degree of the sediment,it is concluded that the organic matter content and total nitrogen content are high,the TN pollution is mild pollution,the TP pollution degree is moderate pollution,and the potential ecological risk index of eight heavy metals in the sediment(Er)in descending order is Hg>Cd>As>Cu>Ni>Pb>Cr>Zn.(3)The stability evaluation of the foundation in the subsidence area was carried out,the residual settlement deformation values of the treatment area are all less than the building grade I damage standard,the governance area is divided into five areas: unaffected building area,residual settlement-affected building area,restricted building area,green square and water area,the overall spatial layout scheme of the governance area is formed.(4)Relying on the major project of comprehensive management of Lvjin Lake,according to the principles of unified coordination,maximization of resources,adaptation to local conditions,and taking into account ecological,economic and social benefits,put forward a comprehensive management planning scheme based on the concept of integrated planning of human settlement environment and ecology;The basic principles,construction methods and technical processes of construction surveying,onshore excavation and filling construction,and dredging and dredging construction in the city are introduced,formed a complete set of ecological restoration construction technology system in the city mining subsidence area.(5)Combining the economic concept of PPP and the financing model,combining the treatment of the subsidence area of Lvjin Lake with the major livelihood project of huaihe River Diversion to the north,put forward the market-oriented operation financing mode of “government-led-enterprise participation-risk sharing”,the introduction of social capital participation,alleviates the financial pressure of the subsidence area governance government,improve the quality of engineering construction and management efficiency,improve the quality of engineering construction and management efficiency,optimized project risk allocation,to achieve the green gold lake coal mining subsidence area into waste into treasure,further enhance the ecological carrying capacity of the national land space,bringing considerable “socio-economic-ecological” benefits. |
