The engineering of foundations / Rodrigo Salgado

A full-scale field investigation was performed to determine the effects of soil improvement on the seismic resistance of piles in soft clay. A soil improvement method, called cement deep soil mixin...

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Full-Scale Seismic Testing of Piles in Improved and Unimproved Soft Clay

The design of piles for lateral loads is typically performed using the beam-on-elastic subgrade approach in which the soil response is modeled as a series of discrete nonlinear springs (p-y curves). The p-y curves used in design are based upon empirical rules derived from field experiments. In this study, p-y curves are derived from the bending moments in a pile from a three-dimensional finite element model. A simple elastic-plastic soil model is used as a first attempt at modelling the problem of undrained static loading in clay coils. The results provide insight into the patterns of shear deformation in the soil around the pile and demonstrate the influence of the ground surface upon p-y response. The three-dimensional finite element model is seen to provide a means for investigating effects such as pile-soil-pile interaction in laterally loaded groups, but improved constitutive models for soil and correllations with field experiments are needed.(a) for the covering abstract of this conference see IRRD 824029.

P-y curves for laterally loaded piles derived from three-dimensional finite element model. numerical models in geomechanics. numog iii. proceedings of the 3rd international symposium held in niagara falls, canada, 8-11 may 1989

The effect of a two-layer soil system on the behavior of a laterally loaded pile is investigated analytically in nondimensional terms. A modulus of subgrade reaction is used to define the soil stiffness; the stiffness of the surface layer is defined in terms of that of the underlying layer. The complete range of relative stiffness and relative thickness of the two layers is investigated. The surface layer is shown to exert an overwhelming influence on the behavior of a soil-pile system.

Closure of "Laterally Loaded Piles in a Layered Soil System"

Nonlinear Analysis of Single Model Piles Subjected to Lateral Load in Sloping Ground

In the past decades, the behavior of pile foundations in liquefiable sands has been studied extensively; however, similar investigations of soft clays or static/seismic response of piles in improved soft clay soils are scarce. Despite the widespread presence of this soil type in high seismic regions and the frequent need to locate bridges and buildings in soft clay, only a few investigations have been carried out to guide engineers in evaluating the effectiveness of ground improvement techniques on increasing the lateral resistance of pile foundation embedded in soft clay, and no numerical models have been validated to evaluate this approach. Thus, the objective of this research was to develop modified p-y curves for Winkler analysis to characterize the lateral load behavior of a single pile embedded in a volume of improved clay surrounded by unimproved soft clays. A detailed literature review was completed in the study, aiming to gain knowledge on the development and fields of applications together with limitations of different ground improvement techniques. The ability of each available analysis method for lateral loaded piles was assessed for determining lateral responses of pile foundation in a volume of improved soil surrounded by unimproved soil. A method of developing p-y curve modification factors to account for the effect of the improved soil on enhancing the lateral load behavior of a single pile embedded in soft clay was developed by integrating the effectiveness of the improved soil into the procedures of constructing p-y curves for stiff clay recommended by Welch and Reese (1972). It was achieved by estimating the effective length for a infinitely long soil layer with soil improvement so that the fraction of the load resisted by the soil improved over a

https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=3056&context=etd

Jin-wei Huang

Papers

Development of modified p-y curves for Winkler Analysis to characterize the lateral load behavior of a single pile embedded in improved soft clay