HEAVE MEASUREMENTS WITHIN A LARGE EXCAVATION.

Abstract

Field measurements of base heave in a large powerhouse excavation in glacial till and interglacial sand and gravel deposits are presented. To aid in the interpretation of field measurements, an elaborate simulation of stage excavation by finite elements was performed. The deformation modulus thus backfigured generally correlates with the design values previously determined in the field and laboratory testing of the subsoil. Predictions of foundation settlement are made on the basis of this correlation. Factors such as excavation geometry, soil properties, and the presence of shallow bedrock are examined, along with their impact on ground movement during excavation. A method of incorporating boundary stiffness terms to simulate the soil-rock interface in a finite element analysis is also described.