(1. Faculty of Architectural，Civil Engineering and Environment，Ningbo University，Ningbo，Zhejiang 315211，China；
2. Geotechnical Engineering Research Centre，Tianjin Research Institute for Water Transport Engineering，
Ministry of Transport，Tianjin 300456，China)
Abstract：The squeezing effect of plastic tube cast-in-place concrete piles(TC pile) was investigated by combining with three technologies of transparent soil，particle image velocimetry(PIV) and close-range photogrammetry. The soil deformations caused by TC pile installation were explored and compared with those induced by conventionally jacked pile. The test results show that the maximum displacement caused by casing jacking for expanded-conical-base pile is decreased by 40% compared with that for expanded-flat-base pile. The affected zone extends as far as 11 times the radius of pile shaft at the surface in the case of the flat shoe，whereas in the case of the conical shoe，the affected zone up to 6 times the radius of pile shaft from the pile centerline. The soil movement caused by casing extraction occurs mainly in the early stage of extraction. The maximum displacement and affected zone caused by casing extraction for the conical base are about 57% and 33% of those for the flat base respectively. However，during the jacking of TC pile，the casing driving is the dominant factor causing the soil deformation，while the recovery of soil deformation caused by casing extraction is small. The displacements generated by jacking a conventional pile with the same diameter is consistent with those induced by TC pile installation，but its affected zone is slightly smaller.
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2017, Vol. 36 
