Physical Model Experiments on Water Infiltration and Failure Modes in Multi-Layered Slopes under Heavy Rainfall
Physical Model Experiments on Water Infiltration and Failure Modes in Multi-Layered Slopes under Heavy Rainfall
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DOI：
10.3390/app10103458
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发表时间：
2020-05
期刊：
影响因子：
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通讯作者：
Junfeng Tang;Uchimura Taro;Dong Huang;Jiren Xie;Shangning Tao
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文献类型：
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作者：
Junfeng Tang;Uchimura Taro;Dong Huang;Jiren Xie;Shangning Tao
为了评估中间粗层在强降雨期间对边坡稳定性的影响，了解水的运动和边坡破坏的发生是很重要的。为了阐明多层边坡中水的入渗特征，评估其对边坡破坏模式的影响，研究了8组物理边坡模型。结果表明，粗层（5.54 × 10−6 cm/s）的非饱和导电性远低于细层（1.08 × 10−4 cm/s），导致毛管屏障在较低含水量下工作。嵌入在较细层之间的中间粗层可能最初将入渗限制在上覆较细层内，从而延缓入渗，并最终在倾斜斜坡内引起侧向分流。在模型试验中出现了两种不同的破坏模式：单层边坡群趾部发生地表滑动，多层边坡群趾部发生管状破坏，雨水积聚后沿界面被分流，再沿中间粗层下坡方向突破。毛细管屏障引起的侧向导流和倾斜角度可能是影响破坏模式差异的主要因素。结果还表明，较粗的土层可能对边坡的稳定性产生不利影响。
To assess the influence of an intermediate coarse layer on the slope stability during heavy rainfall, knowledge about water movement and how slope failure occurs is important. To clarify the characteristics of water infiltration in a multi-layered slope and assess its influence on the slope failure modes, eight groups of physical slope models were investigated. It was found that the unsaturated hydraulic conductivity in the coarse layer (5.54 × 10−6 cm/s) was much lower than that of the fine layer (1.08 × 10−4 cm/s), which resulted in the capillary barrier working at a lower water content. Intermediate coarse layers embedded between finer ones may initially confine the infiltration within the overlying finer layers, delaying the infiltration and eventually inducing a lateral flow diversion in the inclined slope. Two different failure modes occurred in the model experiments: surface sliding occurred at the toe in the single-layer slope group and piping occurred at the toe in the multi-layered slope as the rainfall water accumulated, was diverted along the interface, and then broke through in the downslope direction of the intermediate coarse layer. The lateral flow diversion caused by the capillary barrier and the tilt angle may be the major factors influencing the difference of the failure modes. The result also revealed that the coarser layers may have negative effects on the slope stability.