How do numerical models help predict ground behavior in soft-rock mining?

Soft rocks, characterized by poor mechanical properties and sensitivity to environmental factors like water, bridge the gap between soils and hard rocks.

Accurate prediction of ground behavior in these materials is crucial for the safety and stability of geotechnical structures like tunnels and slopes, which are prone to large deformations and instability (Douglas Partners, n.d.).

Numerical modeling, employing techniques such as the Finite Element Method (FEM), Finite Difference Method (FDM), and Discrete Element Method (DEM), is indispensable for simulating complex soft rock responses.

FEM offers flexibility for complex geometries, while FDM is efficient for simpler problems and dynamic analyses. DEM is particularly suited for discontinuous materials where fracturing is dominant (TU Freiberg, n.d.).

Accurate modeling relies on precise geotechnical parameters (e.g., cohesion, friction angle, Young’s modulus) and appropriate constitutive models that capture non-linear behaviors like strain hardening/softening, creep, and swelling.

They also assess slope stability, especially when weak interlayers and water infiltration are present (Geotechdata.info, n.d.).

Commercial software like PLAXIS (FEM-based), FLAC3D (FDM-based), and GeoStudio (LEM/FEM-based) provide tools for these analyses, offering various constitutive models and features for complex scenarios. Despite their power, models are simplifications, requiring engineering judgment and continuous validation (Douglas Partners, n.d.).

Which numerical method FEM, FDM, or DEM do you think would be most useful for modeling fractured or heavily jointed soft rocks?