Model Pile Groups Under Oblique Pullout Loads – an Investigation

Abstract

Experimental investigations on model pile groups of configuration, 1 · 1(single pile), 3 · 1, 2 · 2 for embedment length to diameter ratio, L/d ¼ 38, were conducted in uniform dry medium dense Ennore sand. The spacing of piles in the groups varied from 3 to 6 pile diameter. Soil-pile friction angles were d ¼ 16°and 28°. The pile groups were subjected to oblique pulling loads at angles h ¼ 0°, 30°, 60°and 90°with the vertical central axis of the groups. The loaddisplacement response, oblique ultimate pulling resistances have been qualitatively and quantitatively studied. The inclinations of the load, at which maximum oblique resistance for the groups were observed, have been reported. Predictions of ultimate resistance of pile groups under uplift, lateral and oblique pulling loads have been carried out respectively by the methods A comparison of the measured values of the Writers and others with the predicted values showed reasonable agreement.

Numerical study of the 3D failure envelope of a single pile in sand

“…An empirical equation was proposed to consider the interaction effect of combined loads. Patra and Pise [10] carried out model tests with slender aluminum piles in medium dense sand under oblique pull loads. They found the presence of horizontal load, if applied simultaneously, will significantly increase the ultimate vertical load.…”

On the behavior of piles in non-cohesive soil under combined horizontal and vertical loading

“…Patra and Pise [13] reported model test results with aluminum piles D = 19 mm/L = 722 mm (L/D = 38) in medium dense fine sand under oblique pull and analyzed these with regard to ultimate loads. They found that for both single piles and pile groups the ultimate vertical load can be significantly increased by a horizontal load acting simultaneously.…”

Pile groups under vertical and inclined eccentric loads: Elastoplastic modelling for performance based design

“…O'Neill et al (1982); Mandolini and Viggiani (1997); Ismael (2001); McCabe and Lehane (2006); Dai et al (2012)), small-scale laboratory testing (e.g. Lee and Chung (2005); Sales et al (2017); Patra and Pise (2006)), centrifuge modelling (e.g. Zhang et al (1998); Lam et al (2009); Zhou et al (2007)), theoretical analysis (e.g.…”