| 摘要: |
| 天然降雨和泄洪雾化雨入渗对大坝下游边坡有两方面的影响，一方面含水率升高使土体容重增加，导致下滑力增加；另一方面土体含水率升高，土的抗剪强度参数降低，阻滑力降低。两方面问题同时存在，降雨入渗引起的滑坡问题时有发生。本文设计了室内人工降雨物理模型试验，研究在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，研究暂态饱和区的扩展过程，计算各个时刻边坡的安全系数，分析随着入渗发展对边坡稳定性的变化过程及其特征。试验结果表明：降雨入渗率先在边坡表面形成暂态饱和区，随着降雨进行，暂态饱和区逐渐扩大；降雨强度越大，降雨阶段形成的暂态饱和区越大，边坡稳定安全系数的降低幅度就越大；得到了降雨阶段水分入渗深度随降雨历时和降雨强度的经验公式。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，边坡的稳定性持续降低，水分入渗在一定的延后时间内继续对边坡造成危害。降雨强度为144 mm/h条件下稳定安全系数在6 h时降到了最小值1.196，最大降幅为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（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（U1765202） |
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| Study on Slope Stability Weakening Process along with Infiltration as Rainfall |
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LIN Guocai1, XIE Xinghua2, RUAN Huaining1, ZHU Zhende1, Lu Bin2, XU Chencheng1, Lu Xiaogang3
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1.College of Civil and Transportation Engineering,Hohai University;2.NanjingSHydraulicSResearchSInstitute,State Key Laboratory of Hydrological Water Resources and Hydraulic Engineering Science;3.Haidong Ping'an District Water Conservancy Bureau
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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 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 this paper, 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 continuous, 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 the rainfall duration and rainfall intensity was obtained. Increasing the rainfall intensity would make the water content of the test sand closer to the saturated water content, but the sand wouldn’t completely saturated. The effect of rainfall infiltration in slope not only occurred during the rainfall process. After the rainfall stops, 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 |
