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从化学腐蚀下岩石细观结构的变化出发,研究水化学溶液对岩石中裂纹的腐蚀作用。运用地球化学矿物-水反应的溶解动力学,考查水-岩反应化学溶液中不同时间段离子浓度的变化,从理论上探讨化学腐蚀下等效裂纹扩展的定量化分析方法。通过质量守恒定律计算出裂纹在迹长及隙宽方向的变化,将水化腐蚀等效成有效裂纹长度,建立了水-岩化学作用下等效裂纹扩展的计算公式并计算应力强度因子。通过对砂岩的研究结果表明,水-岩化学作用对岩石裂纹的扩展有显著影响,并且具有时间效应。同时,水化学溶液的离子浓度及pH值大小对裂纹的扩展存在影响,其中pH值的变化对岩石的断裂力学效应更加显著。当溶液的酸性越强或碱性越强,腐蚀越大,裂纹扩展越快;pH值为中性时,腐蚀作用得到较大缓解,裂纹发展缓慢。为定量研究裂隙岩体在水岩化学作用下的细观机理提供了一种新的思路。
Based on the change of the rock mesostructure under chemical corrosion, the corrosion effect of the hydrochemical solution on the cracks in the rock was studied. Based on the dissolution kinetics of geochemical mineral-water reaction, the change of ion concentration in water-rock reaction chemical solution at different time is investigated. The quantitative analysis method of equivalent crack propagation under chemical etching is theoretically studied. Based on the law of conservation of mass, the change of crack in the trace length and the width of the slot is calculated, and the hydration corrosion is equivalent to the effective crack length. The formula of equivalent crack propagation under water-rock chemistry is established and the stress intensity factor is calculated. The results of sandstone research show that water-rock chemistry has a significant effect on the propagation of rock cracks and has a time effect. At the same time, ion concentration and pH value of hydrochemical solution have an impact on the crack propagation, and the change of pH value has more significant effect on the fracture mechanics of rock. When the solution is more acidic or alkaline, the stronger the corrosion is, the faster the crack growth is. When pH is neutral, the corrosion is greatly alleviated and the crack develops slowly. It provides a new idea for the quantitative study of meso-mechanism of fractured rock mass under water-rock chemistry.