Effect of pile driving on adjacent piles in clay

Abstract

When a pile is driven into clay, horizontal and vertical movements are developed in the soil surrounding the pile. These movements will tend to develop axial forces and bending moments in adjacent piles that have already been installed. Possible consequences for these piles are (i) structural damage or cracking (of concrete piles) arising from the induced bending moments, (ii) tensile failure of the piles due to the induced axial forces, and (iii) lifting-off of the pile tip from the bearing stratum due to the axial induced movements. This paper describes the results of a theoretical analysis of the bending moments and axial forces developed in a pile due to driving of an adjacent pile in clay. The analysis uses approximate distributions of horizontal and vertical soil movements caused by pile driving, developed from a "strain-path" analysis, together with inferences from model pile test data. An examination is made of various factors that may influence the induced bending moments and forces, including pile spacing, depth of penetration of the adjacent pile, and number of piles driven. For a number of published case histories comparisons are made between theoretical and measured axial and lateral pile movements. In general, satisfactory agreement is found. Key words : foundations, lateral movements, pile driving, settlement, soil displacement.