Geotechnical assessment

Geotechnical Assessment is an essential part of both design and management of sustainable landfills.

Construction and operation of landfills requires knowledge on embankment/dike construction, soil excavation, and in general on soil/structural element interaction (geosynthetics, retaining wall, excavation with sheet piles etc).

All these fields are well consolidated in the civil/geotechnical engineering theory. Two main important aspects differentiate and complicate the geotechnical assessment of the landfills:

• Only in rare cases can the waste be considered “geotechnically” similar to typical soils (like sand, clay, silt etc). This discrepancy is even stronger when the waste under investigation is municipal solid waste or in general organic waste
• Contrary to typical soil, the organic waste undergoes biochemical transformations (gasification of the organic waste fraction) leading to a morphological and structural change of the waste characteristics. Properties like waste porosity, compressibility, stiffness, shear strength change in relation to biological degradation timeline.

These factors make geotechnical assessment of landfills interesting but complex.

There are 2 main types of calculations to perform in a landfill:

1. The evaluation of the slope stability
2. The evaluation of the soil (landfill & subsoil) displacements

Other studies of important and frequent geotechnical issues that Pollux delivers are:

• Geo-synthetics stress-strain behaviour
• Pipe and subsoil deformation under a load  Show me
• Drainage pipe design
• Ditch and anchorage trench design

Pollux Consulting uses specialised 2D and 3D software packages such as Plaxis 2D, Slide and Plaxis 3D to investigate all these geotechnical cases.