| 摘要: |
| 天然降雨和高坝泄洪雾化雨入渗对大坝下游边坡有两方面影响，一是升高含水率使土体重度增加，导致其下滑力增加；二是升高土体含水率，降低土抗剪强度和阻滑力。因此，降雨入渗引起的滑坡时有发生。对此设计了室内人工降雨物理模型试验，分析研究砂土质边坡降雨入渗情况下，边坡内部水分扩散过程和规律以及暂态饱和区扩展过程，计算各入渗时刻边坡的安全系数，分析入渗发展对边坡稳定性变化过程及其特征的影响。试验分析结果表明：降雨入渗率先在边坡表面形成暂态饱和区，随着降雨持续，暂态饱和区逐渐扩大；雨强越大，降雨期间形成的暂态饱和区越大，边坡稳定安全系数的降幅就越大；试验得到了降雨入渗深度随降雨历时和强度变化的经验式。增大降雨强度会使试验砂土的含水率更接近于饱和含水率，但无法使砂土完全饱和。降雨入渗对边坡稳定性的影响不仅仅发生在降雨过程中，降雨停止后，水分入渗过程延续，边坡稳定性持续降低，水分入渗在一定的延后时间内继续威胁边坡安全。雨强为144 mm/h条件下边坡稳定安全系数在6 h时降到了最小值1.196，最大降幅达38.2%。 |
| 关键词: 降雨入渗 暂态饱和区 非稳定渗流 物理模型试验 |
| DOI： |
| 分类号:TU457 |
| 基金项目:国家重点研发计划资助项目（2016YFC0401704）; 国家自然科学基金重点项目(51539006); 国家自然科学基金雅砻江联合基金资助项目（U1765202） |
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| Study on slope stability weakening process along with infiltration by rainfall |
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LIN Guocai1,2, XIE Xinghua2, RUAN Huaining1, ZHU Zhende1, LU Bin2, XU Chencheng1,2, LU Xiaogang3
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1.College of Civil and Transportation Engineering, Hohai University, Nanjing;2.State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing;3.Haidong Ping’an District Water Conservancy Bureau, Haidong
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| Abstract: |
| Natural rainfall and atomization rain will make infiltration into slope with a certain time process, which influences the slope stability in the downstream of high dam. The influence manifests in two aspects, on the one hand, the increase of water content increases the bulk density of the soil, resulting in an increase in the sliding force of slope; on the other hand, the soil moisture content increases, which makes the shear parameters of slope reduced. Engineering events caused by rainfall infiltration occur frequently. In the study, an indoor artificial rainfall physical model test was designed to study the process and law of water diffusion and the expansion process of transient saturation zone in the slope during rainfall infiltration of sand slope. The safety factor of slope was calculated to analyze the effect of rainfall infiltration process on slope stability. The test results showed that a transient saturated zone was formed firstly in the surface of the slope. As the rainfall continued, the transient saturation zone gradually expanded. The greater the rainfall intensity, the larger the transient saturation zone formed by the rainfall process, and the greater the reduction of the slope safety factor. The empirical formula of the water infiltration depth along with the rainfall duration and rainfall intensity was obtained. Increasing the rainfall intensity would make the water content of the test sand closer to the saturate water content, but the sand wouldn’t completely saturate. The effect of rainfall infiltration in slope not only occurred during the rainfall process. After the rainfall stopped, the water infiltration process kept existing, the stability of the slope continued to decrease, and the water did harm to the slope in a certain delay time. In the case of rainfall intensity of 144 mm/h, the stability safety factor of the slope decreased to a minimum of 1.196 at 6 h, with a maximum decrease of 38.2%. |
| Key words: rainfall infiltration transient saturated zones unstable seepage physical model test |
