【摘要】 采动破坏岩体易与采空区水、气发生一系列物理化学作用,促使裂隙发生导水能力降低的自修复现象;研究揭示导水裂隙的自修复机理对于科学评价地下水生态恢复能力、合理制定裂隙限流的保水采煤对策等具有重要的指导意义。基于砂质泥岩裂隙岩样在酸性和碱性水溶液条件下的水-CO₂-岩相互作用实验,揭示了裂隙在黏土矿物遇水膨胀以及次生矿物或沉淀物充填作用下的自修复机理和规律。结果表明:无论酸性或碱性水溶液条件,裂隙均具备自修复能力,但酸性水溶液条件下的自修复效果更好。裂隙自修复过程中存在渗透率"先快后慢"的分区特征;首先出现以裂隙面黏土矿物遇水膨胀作用为主引起的渗透率快速下降现象,其下降速度在碱性水条件下更快;其次随着时间的累积,裂隙面岩石矿物溶解、溶蚀形成的离子与水溶液中的阴阳离子、游离CO₂发生离子交换化学反应,引起高岭石等衍生矿物或Fe（OH）₃等沉淀物的生成,这些新的物质在裂隙面逐渐吸附堆积,不断降低裂隙的导水能力。由于实验砂质泥岩中铝硅酸盐矿物含量偏低,无法充分消耗加大通入量的CO₂,导致多余的CO₂会以碳酸的形式对裂隙面矿物形成溶蚀作用,从而引起裂隙开度及其水渗流能力的提高,表现出对裂隙岩石自修复进程的阻滞作用。更多还原

【Abstract】 A series of physical or chemical reactions will happen between the damaged rock mass and underground water and gas after the underground coal mining.In the process,the water permeability of mining induced fracture will gradually be reduced which leads to the self-healing phenomenon of the water-conducted fracture.It is of great importance to study the self-healing mechanism on the scientific evaluation of ecological restoration of underground water and drawing up the water preserving mining method of fracture current-limiting.By conducting the water-CO₂-rock interaction experiments with acidic/alkaline water solution and fractured sandy mudstone samples,the self-healing mechanisms and its development law are revealed under the effect of water swelling in clay mineral and filling and plugging of the secondary minerals or precipitate.The study results refer that the fractures in the rock sample have self-healing ability no matter when the rock in the acidic or alkaline water solution,and generally,the self-healing effect will be more significant while in the acidic water solution.In the self-healing process,the decline of permeability presents a partition characteristic of rapidly first and then slowly with time.The first rapid decline process is caused by the water swelling of clay mineral,and in the alkaline water solution condition the decline speed will be faster.Then,as time goes on,ions due to the dissolution or corrosion or rock minerals will react with the anion and cation and the free CO₂ in the water solution.Furthermore,derived minerals such as Kaolinite and precipitate such as Fe（OH）₃ will be generated.These new materials adsorb and accumulate on the fracture face little by little,which lead to the decent of fracture permeability.Due to the low content of aluminosilicate minerals in the sandy mudstone samples,the increase input of CO₂ in the acidic water solution may slow down the self-healing process of the fracture.Partial CO₂ could not be depleted in the chemical process of WRI,the residual CO₂ will dissolve and erode the rock minerals on the fracture surface in the form of carbonic acid.Then the fracture aperture will be enlarged,and the permeability may be increased.更多还原