Some lateral load tests on model pile groups : Selby, A G; Poulos, H G Univ of Sydney. School of Civil and Mining Engineering research reportNR457, Oct 1983, 61P

Abstract

A series of lateral load tests on model pile groups was made, in which some piles carried strain gauges near their heads for measurement of moment and shears. The piles were positioned in a sand tank, and sand was rained around them, after which a segmented pile cap was clamped around the pile heads, at an overhang above ground level of 100 mm. Strain gauge readings were taken at several points during a lateral loading pattern of load cycling followed by load to failure. Results showed that leading piles in a group carried much higher cap level moments and shears than trailing piles. It is suggested that this shielding effect may be caused by a reduction in passive pressure on trailing piles by sand particle movements away from the passive pressure zone of a trailing pile. It was also shown that considerable residual moments and shears were induced in piles in the model groups by one or more cycles of load, and that load cycling increased moments but not shears. Analyses of the model tests by three methods failed to predict the non-uniformity of load effects. The most comprehensive of these analytical methods, however, made good predictions of pile behaviour in other respects. (Author/TRRL)