Assessment of basal heave for wide excavations using the finite element method

• Main Author: Tan, Christina Ai Wei.
• Other Authors: Goh Teck Chee, Anthony
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/53219
• Institution: Nanyang Technological University

Braced excavation is gaining popularity as a construction method. To design an excavation safely, designers must have a good knowledge of the behavior of excavations, especially bottom basal heave. Besides, they should also know the limitations of using conventional methods and finite element methods to obtain the factor of safety. In this report, a two-dimensional finite element parametric study was conducted to analyze effects of varying depth of embedment, thickness of clay layer and stiffness of wall and how these factors affect basal heave factor of safety and lateral displacements of the walls. This was done using the C-phi strength reduction technique. A total of 27 cases were considered. Results obtained from finite element method (Plaxis 2D) were compared with the conventional Terzaghi method. Results showed that finite element method produced more conservative results as it takes into account factors that are not considered in conventional method like depth of embedment and wall stiffness. However there are also cases where finite element method proves to be over-estimated. Hence, both of these methods should be applied accordingly.