EGS and its main parameters

The engineering geological system (EGS) is the combination of the geological environment (rock, soil, structure, water, relief and processes) and the proposed engineering structure, treated as one interacting system. The structure changes the ground, and the ground controls the safety and cost of the structure.

Main parameters for evaluation

1. Lithology: rock/soil type, grain size, mineral composition, hardness.
2. Geological structure: bedding, joints, faults, folds, shear zones; their orientation, spacing, persistence, aperture and infilling.
3. Weathering and alteration: degree and depth of weathering.
4. Physical and mechanical properties: density, porosity, strength, deformability, slake durability, swelling.
5. Rock mass quality: RQD, RMR, Q and GSI classification.
6. Hydrogeology: water table, permeability, seepage, springs, pore pressure.
7. Geomorphology and slope conditions: slope angle, drainage, overburden thickness, landslide features.
8. Geodynamic processes and hazards: landslide, erosion, flood, seismicity, active faults.
9. In-situ stress and temperature (for deep tunnels).
10. Construction materials availability.