A continuum-discrete hierarchical multi-scale computational framework for modelling mechanical behaviour of MICP-treated soil

Soil improvement involves mechanical, chemical, and bio-chemical methods aimed at enhancing the strength and stiffness of soils for engineering applications. Among emerging approaches, Microbially Induced Calcite Precipitation (MICP) has gained attention as an environmentally sustainable and cost-effective alternative to conventional methods. However, MICP-treated soils exhibit complex mechanical behavior characterized by bonding types, grain irregularity, and anisotropic tensile and shear responses. Bond degradation and particle breakage further govern the post-failure response, making reliable prediction of elastoplastic behavior challenging.

This project proposes a hierarchical multi-scale numerical framework to capture the coupled micro- and macro-mechanisms governing MICP-treated soils. First, an MP-DEM (Material Point – Discrete Element Method) continuum damage model will be developed to simulate calcite precipitation and progressive bond degradation. Second, a grain cementation and breakage model will be implemented within an MP-LSDEM (Material Point – Level Set Discrete Element Method) framework to represent irregular particle geometry and contact evolution. These components will be integrated into a representative volume element (RVE) using a suitable particle packing strategy. Finally, a hierarchical multi-scale model will be established and validated through benchmark simulations and parametric studies.

The proposed research aims to improve predictive capability for MICP-treated soils and establish a robust computational framework for their multi-scale modeling.