Forecasting Ground Deformation

Asst/Prof James Doherty

Geotechnical engineers are responsible for building models to forecast the behaviour of structures in contact with the ground. In this talk, it will be argued that we have a fairly robust and consistent frame work for modelling the strength of soils. However, our treatment of soil deformation is confusing and often inconsistent with basic soil mechanics principles, as well as more general modelling principles.

As a result, our ability to forecast deformations for even the simplest geotechnical structures is very poor. Evidence for this will be presented in the form of results from a foundation prediction competition and a review of foundation settlement approaches with respect to a basic modelling philosophy.

A solution will be proposed using a soil model that is simple enough to be applied in routine engineering practice, but sophisticated enough to capture the mechanical behaviour of sands relevant to the footing settlement problem. Emphasis will be placed on an application of the model by presenting an auditable back analysing of several footing load tests. A desktop “app” for deriving soil parameters from laboratory data will be demonstrated.

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