Research progress on coupled restoration technology of active adaptive mining and reclamation in coal-grain overlapping areas with high groundwater level

Coal-grain overlapping areas with high groundwater level are crucial to safeguarding national food and energy security. Scientific and effective theories and technologies for land reclamation and ecological restoration contribute to ecological protection and high-quality development in such areas. Based on the processes and mechanisms of mining subsidence, this paper systematically analyzes the damage characteristics of cultivated land quality across different mining-disturbed zones in coal-grain overlapping areas with a high groundwater level, from the perspectives of deformation slope positions within subsidence basins and groundwater level fluctuations. From the viewpoint of active adaptive restoration, this paper clarifies the evolutionary context and background of policies, regulations and technical standards governing land reclamation and ecological restoration in China. It further explores the practical dilemmas, potential technical approaches and development prospects of the active adaptive restoration concept, and puts forward its preliminary scientific conception and core connotation. Moreover, this paper systematically reviews research on land reclamation and ecological restoration for coal-grain overlapping areas with high groundwater level in China in terms of basic theories and concepts, technical systems and engineering practices. It also analyzes the influencing factors of active adaptive restoration in these areas, including stratigraphic structure, groundwater level depth, mining techniques and schedules, topographic and hydrological features, as well as climatic characteristics. Based on existing research, this paper identifies several urgent key scientific issues that need to be addressed: the synergistic deformation mechanism of mining-induced rock and soil masses in high groundwater level coal mining subsidence areas; the time-lag effect and regulation mechanism of waterlogging caused by mining subsidence; the coupling mechanism between subsidence control and micro-landform reconstruction; and the restoration timing model considering the coupled effects of multiple factors. This paper aims to further expand and innovate the theoretical framework of ecological restoration technologies for coal-grain overlapping areas with high groundwater level, and provide scientific references and technical support for ecological restoration and efficient utilization of soil and water resources in such regions.