Diaphragm walls are rectangular shaped cast in place deep foundations. There are two critical phenomena occurring, according to which the final quality can be affected: bentonite suspension exfiltration and concrete placement. Some imperfections seem to appear recurrently on the surface of the final wall. The defects are known as shadowing pathologies. The main reasons can be attributed to the dual effect of exfiltration mechanisms and kinematics of concrete flow. The objective of this study is developing a numerical tool to prevent the appearance of shadowing pathologies by visualizing the concrete flow in the presence of a bentonite suspension. This paper presents the results obtained from 2D and 3D models of diaphragm wall construction using COMSOL Multiphysics. The CFD model helped in solving a multifluid and particularly a two‐phase flow. The 2D modeling has considered a fresh slurry and an exfiltrated (or polluted) suspension neighboring soil and followed concrete flow with two rheological behaviors in two reinforcement configurations. Then, 3D simulations were compared to actual experimentation results, which were undertaken to construct diaphragm walls in the laboratory. By comparing the results of the simulations to the experimental outcomes, it has been possible to validate the model. The resulting simulations could clearly explain the occurrence of the pathology where the flow pattern and volume fraction of the fluid flow were determined. From the results obtained, it can be conducted that a compliant concrete mix but at the lower limit for the consistency recommendations, leads to pathologies, just like a polluted slurry.

中文翻译：

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连续墙施工的数值模拟

连续墙是矩形的现浇深基础。存在两种可能影响最终质量的关键现象：膨润土悬浮液渗出和混凝土浇筑。一些缺陷似乎反复出现在最终墙壁的表面上。这些缺陷被称为阴影病理学。主要原因可归因于渗漏机制和混凝土流动运动学的双重影响。本研究的目的是开发一种数值工具，通过可视化膨润土悬浮液存在下的混凝土流动来防止阴影病理的出现。本文介绍了使用 COMSOL Multiphysics 从地下连续墙施工 2D 和 3D 模型中获得的结果。 CFD 模型有助于求解多流体，特别是两相流。二维建模考虑了新鲜泥浆和邻近土壤的渗出（或污染）悬浮液，并遵循两种加固配置中具有两种流变行为的混凝土流动。然后，将 3D 模拟与在实验室建造地下连续墙时进行的实际实验结果进行比较。通过将模拟结果与实验结果进行比较，可以验证模型。由此产生的模拟可以清楚地解释病理学的发生，其中确定了流体流动的流动模式和体积分数。从获得的结果可以看出，合规的混凝土混合物但在稠度建议的下限下会导致病变，就像受污染的浆料一样。