高原高寒矿区生态地质层修复中冻土层构建与应用

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

冻土层在高寒地区的生态平衡中起着重要作用,但冻土层的修复与保护在高原高寒矿区生态环境治理中经常被忽略,鲜有研究。以木里矿区聚乎更区生态环境综合整治实践为例,通过对原始冻土层的平面分布、垂向分布、地层结构、地温变化等特征的分析,针对破坏的土壤层、地表层、冻土层、煤层顶板岩层等不同研究对象的生态地质层剖面,按照模拟季节性冻土、多年冻土差异变化特征及其生态地质功能的思路,在利用构建人造冻土层和回填层二元结构冻土生态地质层剖面模型的基础上,提出了以冻土概况调查、剖面模型建立、搭接融合、确定回填时间、设计表层保水、布设截排水沟、地貌重塑为流程的人工构建冻土层的修复技术,以实现人造冻土层在物质结构、地下含隔水层结构及水力联系、水源涵养等方面的功能基本达到原始冻土层的水平,同时提供更多对冻土保存有利的条件。采用探坑、钻孔岩心取样和孔内长期地温监测等不同方法手段在以往矿区渣山区和新回填修复采坑内对比实验,证实了原渣山压覆区域多年冻土顶界在稳定抬升,采坑内新回填区已经开始形成新的冻土层;通过对比渣山区自然恢复冻土层和采坑内人工修复冻层形成的时间和厚度,表明人造冻土层构建更有助于该区冻土快速恢复。

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 struc-ture,and ground temperature changes of the original frozen soil layer,and targeting the ecological geological layer profiles of different re-search 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 bin-ary 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,overlap-ping fusion,determining backfill time,designing surface water retention,laying interception and drainage ditches,and reshaping the ter-rain.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 res-toration 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.