Suffusion is a grave threat leading to accidents in embankment dams across the world. The process has been widely studied experimentally and numerically with gap‐grading cohesionless soil. One of the direct observations in the studies is the finer particle loss of the soil. However, the movement of the finer particles in the numerical models is commonly predicted with an empirical law. This paper proposes a theoretical particle movement model based on the force balance of soil particles and a probability distribution of the soil pores under one‐dimensional upward seepage flow. In the proposed model, the velocity and the critical movement state of soil particles were deduced, and a method to predict the critical hydraulic gradient was established. The finer particle movement rate was estimated theoretically using the particle movement velocity and probability. The model was verified with several experiments and showed a good consistency in the critical hydraulic gradient, seepage velocity, finer particle loss and hydraulic conductivity. Finally, the changes in the soil parameter during the suffusion process, the effects of the hydraulic gradient and initial porosity and the model applicability are discussed quantitatively. The results indicate that the modelled soil parameter changes match well with the movement characteristics of the finer particles observed in the experiment. The particle movement process is very sensitive to changes in the hydraulic gradient and soil initial porosity. The theoretical model provides a new method to assess the suffusion process for internal unstable cohesionless sand soil.

中文翻译：

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渗流作用下无粘性土中水诱导颗粒运动的理论模型

渗水是严重的威胁，导致世界各地堤坝事故的发生。该过程已在间隙分级无粘性土上进行了广泛的实验和数值研究。研究中的直接观察之一是土壤的细颗粒损失。但是，通常用经验定律预测数值模型中较细颗粒的运动。本文基于一维向上渗流下土壤颗粒的力平衡和土壤孔隙的概率分布，提出了一种理论的颗粒运动模型。该模型推导了土壤颗粒的速度和临界运动状态，建立了预测临界水力梯度的方法。理论上，使用粒子移动速度和概率来估计更细的粒子移动速率。该模型已通过多次实验验证，并在临界水力梯度，渗流速度，更细的颗粒损失和水力传导率方面表现出良好的一致性。最后，定量讨论了注水过程中土壤参数的变化，水力梯度和初始孔隙率的影响以及模型的适用性。结果表明，模拟的土壤参数变化与实验中观察到的较细颗粒的运动特性非常吻合。颗粒运动过程对水力梯度和土壤初始孔隙度的变化非常敏感。