Numerical Modeling of the Interaction of Normal Fault and Shallow Embedded Foundation

The consequences to structures caused by permanent fault displacement has been investigated for dip-slip faulting, but not for the effect of the embedment depth on the interaction between a normal fault rupture and shallow embedded foundation. This study investigated the effect of the embedment depth on the interaction of normal fault rupture and shallow foundation using a numerical model validated with centrifuge experiments. It was found that a gapping interaction mechanism and foundation distress occurred at different foundation positions relative to the fault rupture outcrop for an embedded foundation in comparison with a surface foundation. The extent of this area depended on the combined influences of the foundation position, foundation surcharge, embedment depth, and fault dip angle. The sidewalls of the shallow embedded foundation were observed to act as kinematic constraints and had considerable influence on the rotation and displacement of the foundations. With regard to the level of rotation and displacement of the embedded foundation, the lateral earth pressure distribution on the footwall sidewall was similar to that of Rankine active earth pressure in a triangular distribution and on the hangingwall sidewall as a parabolic distribution of passive earth pressure. Foundations laid on loose soil exhibited less rotation than those on dense soil because the fault ruptures were absorbed or bifurcated around both sides of the foundation.

Importance of Distribution Type on Bearing Capacity of an Embedded Foundation in Spatially Varying Soils

The objective of this paper is to investigate the effect of soil variability on bearing capacity of an embedded foundation in the presence of nonstationary undrained shear strength. The nonstationary undrained shear strength is simulated by a nonstationary random field generator based on the spectral representation method. An embedded foundation buried into the soil to two times of width is presented to investigate the influence of spatially variable undrained shear strength on bearing capacity. Firstly, Monte Carlo simulations are carried out to discuss the effect of distribution type, nonstationary gradient parameter, and horizontal autocorrelation length on the bearing capacity from the standpoint of mean value and standard deviation. Then, the influence of the distribution type on the failure probability of nonstationary random soil is also investigated, with the failure probability for the Beta distribution being demonstrated to be always larger than that for the Lognormal and Gamma distribution.

Dynamic Behavior of an Embedded Foundation under Horizontal Vibration in a Poroelastic Half-Space

More and more huge embedded foundations are used in large-span bridges, such as caisson foundations and anchorage open caisson foundations. Most of the embedded foundations are undergoing horizontal vibration forces, that is, wind and wave forces or other types of dynamic forces. The embedded foundations are regarded as rigid due to its high stiffness and small deformation during the forcing process. The performance of a rigid, massive, cylindrical foundation embedded in a poroelastic half-space is investigated by an analytical method developed in this paper. The mixed boundary problem is solved by reducing the dual integral equations to a pair of Fredholm integral equations of the second kind. The numerical results are compared with existing solutions in order to assess the accuracy of the presented method. To further demonstrate the applicability of this method, parametric studies are performed to evaluate the dynamic response of the embedded foundation under horizontal vibration. The horizontal dynamic impedance and response factor of the embedded foundation are examined based on different embedment ratio, foundation mass ratio, relative stiffness, and poroelastic material properties versus nondimensional frequency. The results of this study can be adapted to investigate the horizontal vibration responses of a foundation embedded in poroelastic half-space.