Simulation of cyclic strength degradation of natural clays via bounding surface model with hybrid flow rule

Abstract

Summary Strength loss of natural clays subjected to seismic loading is a critical factor contributing to earthquake‐induced ground failure and associated hazards. This work proposes a bounding surface constitutive law to simulate cyclic strength degradation of natural clays resulting from the loss of structure and attendant accumulation of excess pore pressures. The proposed model employs an enhanced plastic flow rule that can simulate accurately the development of pore pressure and explicitly incorporates soil structure effects. The validation of the model with reference to the experimental evidence available for 3 structured clays shows that with a single set of parameters the proposed model can reasonably represent the mechanical behavior of natural clays under various loading conditions (1D compression, monotonic shearing in compression and extension, cyclic loading, and postcyclic shearing). Particularly, its satisfactory performance in terms of quantification of cyclic strength degradation encourages the use of the model in simulating boundary value problems related to the stability of geotechnical facilities under earthquakes.

Long-term dynamic bearing capacity of shallow foundations on a contractive cohesive soil

“…Ren et al [49] proposed a hyperbolic model to predict the development of undrained pore-water pressure. Shi et al [54] proposed a constitutive model to simulate the degradation of the cyclical resistance of natural clays as a result of the loss of structure and accumulation of pore-water pressure. Galindo et al [18][19][20] propose by evaluating the degradative damage produced, resolve the evolution of the cycles, and generate pore-water pressure under load cyclic, using a mathematical hysteresis model.…”

Offshore Foundations in Low-Plasticity Cohesive Soils: Cyclic Degradation Experimental Evidence and Simplified Numerical Analysis

“…Extreme short-term cyclic events consist of a low to medium number of cycles, rendering time domain numerical analysis with conventional soil constitutive models applicable for assessing cyclic foundation performance. Indeed, several advanced effective stress-based models have successfully been employed to simulate the degradation of cyclically-loaded undrained clay (e.g., Elia and Rouainia, 2016;Shi et al, 2018). Despite their success, the application of such models in practice can be cumbersome due to their complexity and challenging calibration process.…”