Stresses Developed around Displacement Piles Penetration in Sand

Abstract

5Establishing the stress conditions developed around displacement piles in sands is crucial to improving 6 the understanding and modeling of their behavior. High quality experiments and theoretical analyses 7 are giving new insights into the effects of penetration on stress conditions. This paper synthesizes 8 findings from three independent experimental studies on normally consolidated silica sands and a trio 9 of numerical analyses that tackle the problem from different perspectives. The significant degrees of 10 uncertainty in the measurements and predictions are recognized and significant differences between 11 data sets are discussed and largely resolved. Applying a consistent normalized interpretive framework 12 leads to clear common trends regarding how installation affects the stress regime. While the main 13 emphasis is placed on the radial effective stresses developed around pile shafts, the circumferential 14 and vertical stress states are also considered. 15

Advanced laboratory testing in research and practice: the 2nd Bishop Lecture

“…Interesting comparisons are presented from Yang et al (2014) in Figures 39 and 40, plotting the σr′ and σθ′ predictions transmitted by Professor Einav against r/R (Zhang et al, 2013). The stresses are normalised by predicted qc, as are the experimental equivalents shown in Figures 26 and 27.…”

Distributed fibre-optic monitoring of an Osterberg-cell pile test in London

“…Appropriate instrumentation is crucial so that useful and reliable values for such aforementioned parameters are obtained for the designers (Coop & Wroth, 1989;Randolph, 2003;McCabe & Lehane, 2006). Although a wealth of pile top load-displacement curves is nowadays available (Jardine et al, 2013a(Jardine et al, , 2013bYang et al, 2014), the ability to acquire information along the pile depth opens more opportunities for studying the real pile-soil interaction behaviour.…”

Theoretical breakage mechanics and experimental assessment of stresses surrounding piles penetrating into dense silica sand

“…However, Zhang et al's analysis leads to higher-thanmeasured stresses at low r/R and peaks at slightly lower h/R values. Yang et al (2014) highlighted a further important discrepancy. While the predicted stress regime stabilises to a steady state above h/R 5 10, the radial stress ratios (s' r =q c ) measured on the pile (at r/R 5 1) continued to decline with h/R at much higher levels.…”

“…Further aspects of the latter experiments have been reported by Jardine et al (2013aJardine et al ( , 2013b, who conducted careful comprehensive measurements of the stress distributions developed on and around an instrumented pile. Yang et al (2014) offer a broad review of how these data compare with related predictions made with a range of theoretical approaches and also of data gathered in other experimental studies. This letter sets out detailed predictions made using the approach of Zhang et al (2013) for the calibration chamber stress measurements of Jardine et al (2013aJardine et al ( , 2013b.…”