Experimental and analytical study of X-section cast-in-place concrete pile installation effect

Abstract

A new type of displacement pile, the X-section cast-in-place concrete (XCC) pile, has been developed recently in China. Extensive field and laboratory experiments are being undertaken in order to evaluate the soil displacements during pile installation. The paper describes laboratory arrangements and results of transparent soil model tests aimed at capturing the non-axisymmetric soil displacement field. Results from model tests using the XCC pile are presented to reveal the complete soil displacement patterns (a) in the horizontal plane, and (b) in vertical planes of symmetry. Based on results from the transparent soil tests, a modified cavity expansion model (MCEM) is proposed to predict the radial displacements in any vertical plane induced by XCC pile installation. The radial displacements predicted by the MCEM are compared with data from the transparent soil test and the field experiment. The results show reasonable agreement for all cases, with the proposed MCEM proving more suitable than the conventional (axisymmetric) CEM for predicting the radial displacements induced by XCC pile installation. It may therefore provide a basis in the future for developing predictions of stress changes and, ultimately, shaft capacity of the XCC pile in comparison to displacement piles of circular cross-section.

Noncircular Cavity Expansion in Undrained Soil: Semi-Analytical Solution

“…Existing solutions are mainly limited to axisymmetric cavity problems. This limits application of the cavity expansion approach to 'non-standard' problems such as modeling the penetration behavior of X-section cast-in-place concrete ('XCC') piles (Liu et al, 2014;Sun et al, 2017;Zhou et al, 2017aZhou et al, , 2018bZhou et al, , 2019, rectangular piles (Basu & Salgado 2008;Seo et al, 2009) and prefabricated vertical drains (PVDs) mandrels (Ghandeharioon et al, 2010). For non-circular cavity expansion (N-CCE) in elastic media, theoretical solutions are feasible using complex variable elasticity (CVE) developed by Muskhelishvili (1954).…”

Model Test Study on Deformation of Snowflake Shaped Steel Sheet Pile Based on OFDR

“…Pile is the most common form of foundation reinforcement, the section forms of which are various, such as square, circular, triangular, and so on. In recent years, with the increasing requirements of energy conservation and emission reduction and green environmental protection in the field of infrastructure construction, some new specialshaped piles have been gradually applied [1][2][3][4][5][6][7][8]. Under the same bearing capacity, specialshaped piles can reduce the use of materials and have good economic benefits.…”

Development of a three‐dimensional soil model for the dynamic analysis of end‐bearing pile groups subjected to vertical loads

“…Modelling of pile foundations subjected to dynamic loads requires accounting for how each pile in the group transfers loads to its surrounding soil (pile‐soil interaction, see eg, ) but also for interaction between vibrating piles in the same group (pile‐pile interaction). The latter suggests that the response of piles is altered by ground waves generated from the vibration of neighbouring piles; therefore, the dynamic impedance of a pile group is not equal to the sum of impedances of each individual pile.…”