Abstract Experimental water retention curve (WRC) obtained under constant volume (isochoric) conditions is crucial in the coupled hydro-mechanical formulation of unsaturated soils and for studying the role of void volume changes on the water retention behaviour of porous media. Experimental WRCs currently available in the literature are often unsuitable for this purpose since they include the effects of change in the void volume with suction that occurs during the course of a WRC test. In this paper, difficulties and limitations associated with obtaining experimental Isochoric WRC (IC-WRC) are discussed. Subsequently, an approach for obtaining IC-WRCs along wetting path is presented, and the experimental wetting path IC-WRCs for three types of soils at different void ratios are obtained. Results from this work as well as data from the literature are utilised to examine trends in the evolution of IC-WRC with void ratio and their prediction using the model recently developed by the authors [36] .

中文翻译：

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等容保水曲线随孔隙比的演变

摘要 在等容（等容）条件下获得的实验保水曲线（WRC）对于非饱和土的水力-力学耦合公式以及研究孔隙体积变化对多孔介质保水行为的作用至关重要。文献中当前可用的实验性 WRC 通常不适合此目的，因为它们包括在 WRC 测试过程中发生的空隙体积随吸力变化的影响。在本文中，讨论了与获得实验性等容 WRC (IC-WRC) 相关的困难和限制。随后，提出了一种沿润湿路径获得IC-WRCs的方法，并获得了三种不同孔隙比土壤的实验润湿路径IC-WRCs。