Precompression stress (sigma(p)) is commonly used as an indicator for the load carrying capacity of a soil and its stress history. Several calculation methods have been proposed to determine sigma(p), but they have proven to be not interchangeable. The aim of this study was to perform a functional evaluation of seven existing methods to test which method would be most recommended to assess soil strength in cultivated fields. This was achieved by investigating the relation of the obtained sigma(p) of undisturbed soil samples to other soil properties and stress history. Additionally, the robustness of the methods was evaluated by checking their sensitivity to perturbation of the measured strains. The two most commonly used methods, the Casagrande method and Gompertz model fit method, were found to be the least suitable to calculate sigma(p). These methods lack robustness and do not yield a significant relation with the relevant soil properties or stress history. Better results were obtained with Intersecting linear regressions or at the inflection point of a fourth-degree polynomial.

中文翻译：

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预压应力各种计算方法的功能评估

预压应力 (sigma(p)) 通常用作土壤承载能力及其应力历史的指标。已经提出了几种计算方法来确定 sigma(p)，但它们已被证明是不可互换的。本研究的目的是对七种现有方法进行功能评估，以测试哪种方法最适合评估耕地土壤强度。这是通过研究获得的未受干扰土壤样品的 sigma(p) 与其他土壤特性和应力历史的关系来实现的。此外，通过检查它们对测量应变的扰动的敏感性来评估这些方法的稳健性。两种最常用的方法，即 Casagrande 方法和 Gompertz 模型拟合方法，被发现最不适合计算 sigma(p)。这些方法缺乏稳健性，并且与相关土壤特性或应力历史没有显着关系。使用相交线性回归或在四次多项式的拐点处获得更好的结果。