In this study, a solid–liquid–gas coupled equation was established to simulate water retention characteristics of highly compacted GMZ bentonite. Then, modelling results were compared with laboratory test results. Results indicate that GMZ bentonite has a strong moisture expansion (or a limit drying shrinkage) characteristic. The control equation can simulate the water absorption and deformation characteristics very well at high relative humidity (or low suction). Environmental scanning electron microscope (ESEM) observation reveals the course grain soil texture of the surface under low relative humidity (RH), while the surface of GMZ bentonite becomes smooth (more fine‐grained soil texture) as RH increases. Differences were found between the porosities calculated by macroexperiment results and microscopic observations with ESEM method. This is because only the interaggregate pores can be observed by ESEM photographs. Additionally, we find that the simulated effective porosities are close to the results calculated by microscopic tests, while the effective porosity is considered as the main flow channel of flow. Further, the intrinsic permeability, the effective water and gas permeability are calculated based on the proposed model. The modelling results coincide well with the laboratory experimental results and support the reliability of the proposed model.

中文翻译：

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自由膨胀条件下压实GMZ膨润土保水率和渗透率的数值模拟

在这项研究中，建立了固液气耦合方程来模拟高密度GMZ膨润土的保水特性。然后，将建模结果与实验室测试结果进行比较。结果表明，GMZ膨润土具有很强的水分膨胀（或极限干缩）特性。该控制方程可以很好地模拟高相对湿度（或低吸力）下的吸水和变形特性。环境扫描电子显微镜（ESEM）的观察表明，在相对湿度（RH）低的情况下，表层土壤的土壤质地逐渐变化，而GMZ膨润土的表面随RH的增加而变得光滑（更细的土壤质地）。通过宏观实验结果计算出的孔隙率与使用ESEM方法进行的显微镜观察发现孔隙率之间存在差异。这是因为通过ESEM照片只能观察到聚集的孔。此外，我们发现，模拟的有效孔隙度接近于通过微观测试计算得出的结果，而有效孔隙度被视为流动的主要流动通道。此外，基于所提出的模型计算本征渗透率，有效水和气体渗透率。建模结果与实验室实验结果非常吻合，并支持所提出模型的可靠性。根据提出的模型计算有效的水和气体渗透率。建模结果与实验室实验结果非常吻合，并支持所提出模型的可靠性。根据提出的模型计算有效的水和气体渗透率。建模结果与实验室实验结果非常吻合，并支持所提出模型的可靠性。