水化学溶液与循环荷载共同作用下石灰岩疲劳变形特性

为研究水化学溶液与循环荷载共同作用对工程岩体稳定性的影响, 选取大连地区地铁隧道石灰岩并加工成标准圆柱形试件，对其进行不同时间水化学溶液作用下的腐蚀试验. 利用MTS Landmark动力试验系统进行腐蚀后的石灰岩在循环荷载作用下的疲劳试验，探讨不同腐蚀时间对石灰岩疲劳变形特性的影响规律.试验结果表明：随着腐蚀时间的增加，在循环开始前发生的轴向变形和单个循环产生的轴向变形均会提高，疲劳破坏时总循环次数显著减小，说明腐蚀效应加速了岩石的疲劳进程.对溶液pH变化以及扫描电子显微镜（SEM）图像分析表明，水化学溶液改变了岩石的微细观结构组织，这是导致岩石动态力学特性发生变化的根本原因.基于试验数据拟合石灰岩疲劳寿命-腐蚀时间曲线，利用该曲线可以进行特定循环荷载与腐蚀环境共同作用下岩石疲劳寿命的预测.
In order to study the effects of combined action of water chemical solution and cyclic loading on the stability of the rock mass, the limestone of Dalian subway tunnel was selected and processed into standard cylindrical specimens, and corrosion tests were carried out under different water chemical solutions at different time. The fatigue tests of corroded limestone under cyclic loading were conducted by using Landmark dynamic test system (MTS) to explore the influence of different corrosion time on limestone fatigue deformation characteristics. Results show that as the increase of corrosion time, the axial deformation before the starting of the cycle and the axial deformation produced by the single cycle, all of them increase and the total cycle number decreases significantly during fatigue failure, which indicates that the corrosion effect accelerates the fatigue process of rock. The variation of solution pH and images by SEM show that the chemical solution changes the microstructure of rock, which is the fundamental reason for the change of rock dynamic mechanical properties. The bridging curve of fatigue lifecorrosion time is fitted based on the test data to predict the fatigue life of rock under combined action of specific cyclic loading and corrosive environment.