Dynamic Loading of Shallow Foundations: Theory Versus Experiment

摘要

In soil-structure interaction problems in soil dynamics, an important subject is the dynamic behavior of embedded foundations. Presented in this thesis is a basic study of the vertical and lateral vibration characteristics of shallow foundations. To obtain a physical understanding of the problem for granular soils, a series of forced vibration tests of square foundations embedded to various depths in sand is performed in a geotechnical centrifuge. A parallel boundary element analysis which can handle nonuniform soil profiles is also used to develop an analytical framework for the problem. By comparing the experimental results with the analytical solution, it is shown that the modeling of the experimental results from vertical vibrations with the homogeneous half- space or square-root half-space theory is directly feasible, while the lateral vibration case requires the use of appropriate Impedance Modification Factors (IMF's) to capture the observed dynamic foundation stiffnesses. Support is also shown for a power law dependence of the embedded foundation equivalent homogeneous shear modulus on the prototype footing half-width and average contact pressure.