Numerical study of braced excavation performance in soft clay
Koh, Eugene Wei Ping
Date of Issue2017-05-12
School of Civil and Environmental Engineering
Numerical study of braced excavation is one area of interest that engineers are interested in. Excavation that requires construction near adjacent building or weak foundation need to be properly examined. Peck (1969) presented the method of envelope for apparent-lateral-pressure diagrams (APD). Such diagrams are design for cuts in sand, cuts in soft to medium clay and stiff clay. Successively, further studies were made to enhance Peck APD, either by comparison of actual pressure envelope, or with the calculated wall deflection chart. Terzaghi (1943) analysed the factor of safety of braced excavation in deep foundation against the basal heave at the bottom of excavation. As braced cuts in soft clay may result in stability issue when heaving occurs at the bottom, hence factor of safety of the braced excavation is a key area of concern. It is important to note Terzaghi (1943) theoretical formulation can be used for shallow or wide excavation (Goh, 1994). On the other hand, Bjerrum and Eide (1956) formulation applies when the H/B is more than 1. A series of cross-comparison will be made to complete the experiment. The results show the prediction of theoretical formulation is align with the exact experimental result. Experiments are run via a finite element method, it is a numerical approach to calculate the continuous problem in soil.
Final Year Project (FYP)
Nanyang Technological University