Construction and application of frozen soil layers in the restoration of ecological geological layers in high-altitude and plateau cold mining area

The permafrost layer plays an important role in the ecological balance of high-altitude and cold regions, but the restoration and protection of permafrost layers are often overlooked in the ecological environment management of high-altitude and cold mining areas on the plateau, and corresponding research still has many gaps. Taking the comprehensive ecological environment improvement practice in Juhugeng Area of Muli Mining Area as an example, through the analysis of the planar distribution, vertical distribution, stratigraphic structure, and ground temperature changes of the original frozen soil layer, and targeting the ecological geological layer profiles of different research objects such as damaged soil layer, surface layer, frozen soil layer, and coal seam roof rock layer, following the idea of simulating the differences in seasonal frozen soil and permafrost changes and their ecological geological functions, Based on the construction of a binary structure frozen soil ecological geological layer profile model using artificial frozen soil layer and backfill layer, a repair technology for artificial frozen soil layer is proposed, which involves investigating the frozen soil overview, establishing the profile model, overlapping fusion, determining backfill time, designing surface water retention, laying interception and drainage ditches, and reshaping the terrain. This technology aims to achieve the material structure, underground aquifer structure, and hydraulic connection of the artificial frozen soil layer The functions of water source conservation and other aspects have basically reached the level of the original frozen soil layer, while providing more favorable conditions for frozen soil preservation. By using different methods such as pit exploration, drilling core sampling, and long-term monitoring of ground temperature inside the borehole, comparative experiments were conducted in the former slag mountainous area of the mining area and in the newly backfilled and repaired mining pit. It was confirmed that the permafrost top boundary in the original slag mountainous area is steadily rising, and new permafrost layers have begun to form in the newly backfilled area of the mining pit; By comparing the time and thickness of natural restoration of frozen soil layers in Zhashan District and artificial restoration of frozen soil layers in mining pits, it is shown that the construction of artificial frozen soil layers is more conducive to the rapid recovery of frozen soil in this area.