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为模拟试验中观察到的石灰岩裂隙摩擦强度愈合现象,提出用压力溶解和应力腐蚀相结合的综合模型来模拟裂隙摩擦强度的愈合。综合模型可同时考虑压力溶解和应力腐蚀对裂隙接触面的改造作用,通过裂隙接触面积的变化表征摩擦强度的愈合。模拟结果表明:压力溶解模型低估了短控制时间内摩擦强度的愈合量,通过进一步的参数敏感性分析发现,随着控制时间的增长,温度的升高显著地提高了压力溶解模型的模拟值,而有效应力的增加对模拟值的影响相对较小;应力腐蚀模型则主要反映应力压缩引起的裂隙接触面积增长;压力溶解模型和应力腐蚀模型结合则能较好地模拟裂隙摩擦强度的愈合。因此,用压力溶解模型模拟裂隙摩擦强度愈合时,特别是在模拟短控制时间内和低温条件下力学占主导作用的愈合时,应考虑应力腐蚀引起的裂隙接触面积变化。
In order to simulate the healing phenomenon of limestone fracture friction observed in the simulation experiment, a comprehensive model combining pressure dissolution and stress corrosion was proposed to simulate the healing of fracture friction. The integrated model can consider the effect of pressure dissolution and stress corrosion on the interface of the fracture, and characterize the healing of the friction through the change of the contact area of the fracture. The simulation results show that the pressure dissolution model underestimates the healing rate of the frictional force within the short control time. Through further parameter sensitivity analysis, it is found that with the increase of the control time, the temperature increases the simulation value of the pressure dissolution model remarkably, While the increase of effective stress has a relatively small influence on the simulation value. Stress corrosion model mainly reflects the increase of fracture contact area caused by stress compression. The combination of pressure dissolution model and stress corrosion model can better simulate the healing of fracture friction strength. Therefore, stress dissolution models should be used to simulate changes in fracture contact area caused by stress corrosion, especially when healing is dominated by mechanics in short simulation times and at low temperatures.