A SIMPLIFIED NONLINEAR EFFECTIVE STRESS FINITE ELEMENT ANALYSIS PROCEDURE FOR EMBANKMENT DAMS SUBJECTED TO DYNAMIC LOADING (EARTHQUAKE, SAN FERNANDO, LIQUEFACTION).

摘要

The demand for safe facilities, especially those of great sensitivity and importance such as large embankment dams, nuclear powerplants, and offshore structures, has affirmed the need for improved analysis tools for evaluating their load-deformation responses and strength behavior, especially in earthquake prone regions.; The dynamic stress-strain, strength, and pore water pressure behavior of water saturated soils in embankment dams and their foundations is highly nonlinear and quite difficult to model in a realistic manner. Therefore simplified analytic procedures are used that often produce unrealistic results. Rigorous step-by-step integration of Biot-type field equations in the analysis of practical engineering projects such as embankment dams is still not feasible because of field exploration and laboratory testing required, cost, and computational hardware limitations.; This dissertation presents a simplified nonlinear finite element analysis technique that incorporates many of the important features of the rigorous procedure, and yet it can be applied to predict the complex load-deformation and pore water pressure behavior of large dams. Analyses of established field cases show that the technique is feasible as a working tool, even when relatively simple constitutive equations are incorporated in the model. The analysis algorithm is based on a fully uncoupled relationship between soil skeleton deformations and pore water pressure as opposed to the coupled equations used in Biot-analysis. Comparisons between analytical predictions and laboratory and field experience show that the procedure is quite satisfactory.