Extension of the effective stress concept to unsaturated soils has been a major concern for decades. Recent studies significantly contributed to the understanding of the fundamentals behind Bishop's parameter χ which is generally used to define the effective stress for unsaturated soils. Examination of the recently proposed methods showed that the contribution of suction to effective stress was often overestimated, especially in high suction range. In this study, considering that soil pores with different sizes contribute differently to the overall hydro-mechanical behaviour, a new method to determine Bishop's parameter χ is proposed. The key variable used in this method is the ratio of the change in water volume to the change in macro-pore void volume due to loading at constant suction. Shear strength data for a weakly expansive clay were used for validation. A good agreement was obtained between prediction and measurement, indicating the validity of the proposed method.

中文翻译：

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根据孔径分布确定Bishop参数χ

将有效应力概念扩展到非饱和土壤是数十年来的主要关注点。最近的研究极大地促进了Bishop参数χ背后的基本原理的理解，该参数通常用于定义非饱和土壤的有效应力。对最近提出的方法的检查表明，吸力对有效应力的贡献常常被高估，尤其是在高吸力范围内。在这项研究中，考虑到不同大小的土壤孔隙对整体水力力学行为的贡献不同，这是一种确定Bishop参数χ的新方法被提议。此方法中使用的关键变量是由于恒定吸力下的载荷引起的水量变化与大孔空隙量变化的比率。弱膨胀粘土的抗剪强度数据用于验证。在预测和测量之间获得了良好的一致性，表明了该方法的有效性。