Simulation of pile cap contribution to the lateral pile performance due to adjacent excavation

Abstract

Laboratory and field test data on the lateral pile response with caps due to adjacent excavation are rather limited. The current practice for design of capped piles is to consider the cap resistance and the pile capacity independent of each other. This paper presents some results from three-dimensional finite-difference analyses that couple the constrain effect of pile cap on the lateral pile performance adjacent to an excavation. The analyses were performed in saturated homogeneous clays, and 38 cases of various pile head conditions restrained by caps including embedded depths of the pile into the cap, relative pile cap–pile modulus and pile cap–pile interface stiffness were carried out. The results have shown that the pile–pile cap connections can significantly affect the distribution of lateral pile deflections and bending moments and change the lateral pile performance, especially with a deep-buried and completely fixed cap. To combine the effects of the pile head embedded depths and the cap material properties, a convenient design method based on statistical analysis for estimating the pile–pile cap connections was presented. The proposed constraint coefficient method can be used to assess the lateral performance of the capped pile and simplify the design procedure of the pile cap due to excavations.