Abstract

The degradation of rock mechanical behavior after cyclic wetting and drying could affect the stability of rock slope, embankment, and tunnel significantly. A series of tests were first conducted on sandstone collected from a reservoir bank slope. The results showed that the mechanical parameters (including tensile strength, uniaxial compressive strength, elastic modulus, and internal friction angle) decrease as the cyclic number of wetting and drying increases. Then, a damage variable, which can consider the combined influence of cyclic wetting-drying and loading, was first proposed based on test results. Further, an improved damage model, which considers the effect of cyclic wetting-drying on internal friction angle and the nonlinear deformation characteristics in the fissure closure stage, was established with statistical damage mechanics. The determination method for the parameters in the proposed damage model was also introduced. Finally, the effectiveness of proposed model was verified by comparing with experimental data. The verification indicates that the results from the improved model agree well with test results, and the improved model can enhance the prediction accuracy over the original model.

摘要

循环干湿后岩石力学行为的退化会显着影响岩石边坡、路堤和隧道的稳定性。首先对从水库岸坡收集的砂岩进行了一系列测试。结果表明，随着润湿循环次数的增加，力学参数（包括拉伸强度、单轴压缩强度、弹性模量和内摩擦角）降低。然后，首先根据试验结果提出了一个可以考虑循环干湿循环和加载共同影响的损伤变量。进一步利用统计损伤力学建立了改进的损伤模型，该模型考虑了循环干湿循环对内摩擦角的影响以及裂隙闭合阶段的非线性变形特性。还介绍了所提出的损伤模型中参数的确定方法。最后，通过与实验数据的对比验证了所提模型的有效性。验证表明，改进模型的结果与测试结果吻合较好，改进后的模型较原始模型具有更高的预测精度。