公路工程

为研究压实和干湿循环综合作用下路堤边坡的长期稳定性，基于室内三轴试验与数值仿真分析，以某高速公路路堤段粉土为研究对象，开展了不同干湿循环次数、压实度下的室内三轴剪切试验，获取了不同干湿循环次数下的抗剪强度参数，并将参数导入至数值仿真模型中开展计算分析，获取了干湿循环对潜在滑移面的影响规律，探索了粉土路堤长期稳定性演变特征。研究表明，压实粉土的强度随干湿循环次数增加而减小，以K=0.93为例，经历干湿循环2、4、6、8次后，黏聚力分别下降24.1%、38.4%、44.1%、51.0%,内摩擦角分别下降11.4%、17.5%、21.9%、25.4%;在不同干湿循环次数下，粉土路堤边坡均存在明显的潜在滑移面，同时滑体上还出现了大量剪切裂隙；路堤边坡在填筑初期的安全系数可满足规范要求，但干湿循环会使路堤的稳定性会出现明显降低，K=0.96、0.93、0.90时，经历8次干湿循环后路堤的安全系数分别下降0.878、0.736、0.587,可见在路堤设计时留足安全储备十分必要，在极端气候偏多的环境下更是应该如此；为提升粉土路堤长期稳定性，提高抵抗病害的韧性，应当重视压实质量和排水。研究成果可为粉土路堤安全储备设计提供有益参考。

To investigate the long-term stability of embankment slopes subjected to the combined effects of compaction and wet-dry cycles, a study was conducted using a combination of laboratory triaxial tests and numerical simulations. The study focused on silt from a highway embankment section, where triaxial shear tests were performed under various wet-dry cycle frequencies and compaction levels. Shear strength parameters were obtained for different numbers of wet-dry cycles, which were then incorporated into a numerical simulation model for analysis. The effects of wet-dry cycles on potential slip surfaces were identified, and the evolution characteristics of the long-term stability of the silt embankment were explored. The results indicate that the strength of compacted silt decreases with the increase in wet-dry cycles. For instance, at a compaction degree of K=0.93, cohesion decreased by 24.1%、38.4%、44.1% and 51.0%, while the internal friction angle decreased by 11.4%、17.5%、21.9% and 25.4% after 2、4、6 and 8 wet-dry cycles, respectively. Notably, under different wet-dry cycle frequencies, potential slip surfaces were evident in the silt embankment slope, accompanied by numerous shear cracks in the slip body. While the initial safety factor of the embankment slope met the standard requirements, the stability significantly decreased due to wet-dry cycles. For K values of 0.96、0.93 and 0.90, the safety factor of the embankment decreased by 0.878、 0.736 and 0.587, respectively, after 8 wet-dry cycles. This underscores the importance of providing sufficient safety reserves during embankment design, especially in regions prone to extreme climatic conditions. To enhance the long-term stability of silt embankments and increase resilience against degradation, emphasis should be placed on compaction quality and drainage. The findings of this study provide valuable insights for designing safety reserves in silt embankments.