The phenomena of dynamic change in the material interfaces and mechanical properties are often involved in the caisson construction. Using conventional methods to simulate these phenomena is quite difficult due to the extremely large deformation. In this study, we proposed an improved soil-water-caisson interaction algorithm with the method of smoothed-particle hydrodynamics (SPH). This algorithm dealt with the support domain truncation of the particles near the blade and applied to avoid the pressure fluctuation. Meanwhile, the application of dynamic particles birth and death method could simulate the whole sinking process of an open caisson with underwater soil excavation. According to the comparison between SPH simulation and centrifuge test, the distribution of sidewall effective soil pressure was consistent, which indicated promising applicability of the algorithm. It should be noted that the considerable excess pore water pressure appeared in the surrounding soil under the blade. With the dissipation of the pressure over time, the effective soil stress increased correspondingly, and it would lead to the increasing difficulty of the sinking process. Therefore, the caisson should be avoided to stop for a long time during the sinking process or it would cause the stagnation of sinking. This algorithm could simulate engineering problems involving underwater construction effectively and provide theoretical and technical support for underwater excavation, shield tunneling, and other engineering problems.

中文翻译：

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改进SPH法对沉井整个沉没过程的数值模拟。

沉箱结构经常涉及材料界面和机械性能的动态变化现象。由于变形很大，使用常规方法来模拟这些现象非常困难。在这项研究中，我们提出了一种改进的土壤-水-沉箱相互作用算法，采用了光滑粒子流体动力学方法。该算法处理了叶片附近颗粒的支撑域截断并应用避免压力波动。同时，采用动态粒子生死法可以模拟开挖沉箱与水下土壤开挖的整个下沉过程。通过SPH模拟和离心试验的比较，侧壁有效土压力的分布是一致的，表明该算法的应用前景良好。应该注意的是，在叶片下面的周围土壤中出现了相当大的过剩孔隙水压力。随着时间的推移压力的消散，有效土壤应力相应增加，这将导致下沉过程的难度增加。因此，在沉没过程中应避免沉箱长时间停下来，否则会导致沉没停滞。