Micro-mechanical Failure Analysis of Wet Granular Matter

TL;DR

This paper introduces a novel fluid-particle model to analyze the shearing behavior of wet granular soils across different saturation levels, capturing complex liquid morphologies and their impact on macroscopic mechanical response.

Contribution

The study presents a new integrated model combining fluid dynamics and discrete particle mechanics to simulate liquid cluster evolution and soil shear behavior.

Findings

Liquid clusters grow, shrink, merge, and split depending on local conditions.

Macroscopic response varies with liquid content and deformation.

Liquid cluster distribution changes significantly near critical loads.

Abstract

We employ a novel fluid-particle model to study the shearing behavior of granular soils under different saturation levels, ranging from the dry material via the capillary bridge regime to higher saturation levels with percolating clusters. The full complexity of possible liquid morphologies is taken into account, implying the formation of isolated arbitrary-sized liquid clusters with individual Laplace pressures that evolve by liquid exchange via films on the grain surface. Liquid clusters can grow in size, shrink, merge and split, depending on local conditions, changes of accessible liquid and the pore space morphology determined by the granular phase. This phase is represented by a discrete particle model based on Contact Dynamics, where capillary forces exerted from a liquid phase add to the motion of spherical particles. We study the macroscopic response of the system due to an external compression force at various liquid contents with the help of triaxial shear tests. Additionally, the change in liquid cluster distributions during the compression due to the deformation of the pore space is evaluated close to the critical load.