Volumetric Shear Strain Threshold and Maximum Shear Modulus: Data Analysis and Resonant Column Experiments

The volumetric shear strain threshold, defined as the strain level at which volumetric changes in the soil begin, is a key parameter for assessing the potential for strain accumulation in soils subjected to cyclic loading. This paper aims to develop a new empirical equation for estimating the volumetric shear strain threshold ( γtv) in cohesive soils. Data analysis and correlation assessments indicate significant impact of small-strain shear stiffness ( Gmax), water content, and plasticity index on γtv. In addition, Gmax is a crucial parameter in advanced constitutive models and is widely employed by engineers in finite-element analyses. Numerous experimental and numerical studies have explored the influence of various factors on the stiffness of geomaterials, including granular, cohesive, and organic soils. The plasticity index, water content, and void ratio negatively influence Gmax, while mean stress and the consistency index exert a positive effect. A further objective of this paper is to evaluate the developed models to estimate Gmax. A database comprising 381 samples from diverse sites is utilized to identify the most straightforward model for predicting γtv and Gmax of cohesive soils based on statistical analyses. The presented models for predicting γtv and Gmax are validated against additional literature data and results of resonant column test results of in situ samples.