Laboratory Study on Response of Single Pile Adjacent to Supported Cut

TLDR: In this article, Chen et al. presented the response of single pile against excavation induced soil movement by conducting model tests at unit gravity and found that the pile head deflection and bending moment of pile decrease exponentially with increasing distance between the pile and the sheet pile wall supporting the excavation.

Abstract: This paper presents the response of single pile against excavation induced soil movement by conducting model tests at unit gravity. The study involves a series of tests conducted on piles of three L/d ratios 10, 20 and 30 embedded in medium dense sand. From the test results it was found that the pile head deflection and bending moment of pile decrease exponentially with increasing distance between the pile and the sheet pile wall supporting the excavation. Analyses of the test results show that the shorter passive pile (L/d = 10) deflects more when compared to a long pile (L/d = 30) and a point of contraflexure for a long pile occurs in the pile section approximately at a depth close to the depth of excavation. The influence of soil movement on the lateral response of pile is also analysed through 3-dimensional finite element analysis. The numerical results thus obtained are validated with the results of experiments. The Mohr–Coulomb material model adopted to represent the soil characteristics predicts the response of pile reasonably and compares well with the response observed in the 1g model test. Design charts are included to predict pile head deflection and maximum moment in pile for the excavation depth ratio (De/Lr) = 0.5. These charts can be adopted to predict prototype pile behaviour by applying scaling law of Wood (Geotechnical modelling, Spon Press, London, 2001). The results of numerical and 1g model tests are validated with the design methods of Chen and Poulos (J Geotech Geoenviron Eng 123(9):802–811, 1997) and Xu and Poulos (Comput Geotech 28:349–375, 2001) and the design charts proposed in this study for deflection of passive pile and sheet pile wall support system are validated with centrifuge test results of Leung et al. (J Geotech Geoenviron Eng ASCE 126(11):947–954, 2000).