水-岩化学作用等效裂纹扩展细观力学模型  

Micromechanical model for equivalent crack propagation under chemical corrosion of water-rock interaction

作　　者：杨慧[1] 曹平[1] 江学良[1,2] 

机构地区：[1]中南大学资源与安全工程学院,长沙410083 [2]湖南城市学院土木工程学院,湖南益阳413000

出　　处：《岩土力学》2010年第7期2104-2110,共7页Rock and Soil Mechanics

基　　金：国家自然科学基金资助项目(No.10972238);湖南省自然科学基金资助项目(No.07JJ6084);中南大学博士生创新项目(No.2009bsxt060)

摘　　要：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 rock microstructure under chemical corrosion, corrosive effect of water and chemical solutions on crack is studied. Using geochemical kinetics of mineral-water interactions and checking ion concentration in chemical solution under different periods, the ways of quantitative methods for equivalent crack propagation under chemical corrosion of water-rock interaction are approached. According to conservation of mass, the evolution equation of crack is obtained and chemical corrosion of water-rock interaction is equivalent to effective crack length. The computational formulation of equivalent crack propagation is set up; and the stress intensity factor is also calculated. An example of sandstone is given; the results show that the influence of water-rock chemical interaction on crack propagation is notable and time-dependent. At the same time, the influence of the solutions with different ion concentrations and different pH values are investigated. The pH is an evident factor which affects the fracture mechanics effect. The greater the acidity or alkaline of solution, the greater the erosion to sandstone and the faster the crack extending. The crack will be propagated slowly when solution is distilled water （pH=7）. A new thought way to quantitatively studying the micromechanism of fractured rock mass in the interaction of water-rock is suggested.

关 键 词：水-岩化学作用 溶解动力学 定量分析 等效裂纹扩展 应力强度因子 

分 类 号：TU451[建筑科学—岩土工程]