A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Civil Engineering

Thesis (M. Eng.) - Asian Institute of Technology, 1993

Ground movements data from 12 braced excavations in soft Bangkok clay were collected and analysed. The data included flexible wall (sheet pile) and rigid wall (diaphragm wall and contiguous bored piles). The maximwn lateral wall movement of flexible walls showed relationship with factor of safety against basal heave and system stiffness similar to those suggested by MANA and CLOUGH (1981) and CLOUGH (1989), however, those of the rigid wall did not show such a relationship. The incremental maximum lateral movement of flexible wall showed similar dependence on the factor of safety against basal heave. Magnitude of maximwn lateral ·movement of flexible wall continues to increase with depth of excavation. in soft clay while that of the rigid wall the increase is not significant. Apparent earth pressures back calculated from strut loads of sheet pile walls were well within TERZAGHI and PECK's diagram. FEM parametric studies using CRISP program were conducted to evaluate various influencing parameters, namely, wall rigidity, strut spacing, surcharge, fixility of wall tip, and existence of pile in excavation area on the magnitude and extent of lateral movement and surface settlement, earth pressure and strut loads. The results were presented.