S - Kam Ng PhD Dissertation Final.pdf - Digital Repository of CCEE ...

103developed by Wathugala and Desai (1991), to characterize soil behavior at the pile-soilinterface and at the far-field. This model is capable of predicting very low effective stressesat the interface during and immediately after pile installation. The numerical simulationprocedure is summarized in the following steps.1. Estimate the strain fields induced in the soil around the pile due to pileinstallation using the principles of the strain path method presented by Baligh(1985).2. Determine the effective stress paths for the soil particles around the pileduring pile installation by integrating the constitutive equations of the (HiSS)-model along the strain paths estimated in step 1.3. Determine the equilibrated effective stresses and pore water pressures at theend of pile installation using the coupled theory of nonlinear porous media.4. Simulate the subsequent soil consolidation around the pile using the finiteelement program ABAQUS.5. Simulate the pile load tests at different times during soil consolidation aroundthe pile using ABAQUS.This numerical procedure was successfully verified based on field experimentsconducted on 43.7 mm (1.7-in) and 76.2 mm (3-in) diameter instrumented pile segmentmodels installed at Sabine Pass, Texas. Using the Sabine clay soil condition, Titi andWathugala (1999) simulated the complete process of two full-stage 10 m (32.8 ft) long pileswith diameters of 300 mm (11.8-in) and 500 mm (19.7-in), starting from pile installation,subsequent soil consolidation, and static load test. Although the proposed numericalprocedure can be used for full-scale piles, no full-scale field pile load tests were available tovalidate the simulated responses. It is a highly technical and complex procedure that requiresin depth understanding of soil mechanics and involves simulation using finite elementmethods. For this reason, it is practically infeasible for pile designers to estimate pile setupusing this procedure.Similar to the numerical procedure proposed by Titi and Wathugala (1999), Whittle