Field Test Research on Embankment Supported by Plastic Tube Cast-in-place Concrete Piles
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ORIGINAL PAPER
Field Test Research on Embankment Supported by Plastic Tube Cast-in-place Concrete Piles Yonghui Chen • Changguang Qi • Hongyue Xu Charles W. W. Ng
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Received: 19 December 2012 / Accepted: 25 April 2013 / Published online: 1 May 2013 Ó Springer Science+Business Media Dordrecht 2013
Abstract The plastic tube cast-in-place concrete pile (TC pile) with a small diameter consists of predriven plastic tube filled with concrete. Based on the case of TC pile-reinforced embankment on soft ground, and according to the monitoring data of the TC pile-reinforced embankment system, the treatment effect and reinforcement characteristics for this system were analyzed. The field monitoring results indicates that the critical height of embankment is about 1.1 times the pile net spacing, and the smallspacing arranged TC piles can be applied to low embankment engineering; the load share rate can reflect the degree of soil arching more better and steadily and exceeds 70 % at the end of monitoring period; the settlements of pile cap and soil between piles mainly occurs in the embankment construction period; the different settlement between pile cap and soil approaches the maximum and then reduces gradually when the embankment height is about 2.2 Y. Chen C. Qi (&) Geotechnical Research Institute, Hohai University, 1# Xikang Road, Nanjing 210098, China e-mail: [email protected] H. Xu Shanghai Urban Construction Design and Research Institute, Shanghai 200125, China C. W. W. Ng Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology, Hong Kong, China
times the pile net spacing. The variation of layered settlement and pore water pressure illustrates that the embankment settlement is mainly caused by the compression of soils within pile length, which is about 90 % of the total settlement; the influence depth of pore water pressure is about 1/3 pile length. Keywords Pile-reinforced embankment Plastic tube cast-in-place concrete pile Field test Load share rate Critical height
1 Introduction The plastic tube cast-in-place concrete pile (hereinafter referred to as TC pile), a new type of pile, is developed by modification of the AuGeo pile technology of Cofra company in Netherlands (Cortlever 2001). Its construction methodology derives from that of traditional driven cast-in-place pile. The TC pile is comprised of the prefabricated pile tip, concrete, single-walled PVC tube, tube joint, inserted steel bars and pile cap, as shown in Fig. 1. Comparing with AuGeo pile, the TC pile has two main differences: (1) The price of PVC (polyvinyl chloride) tube is half of that of HDPE (high density polyethylene) tube, which decreases the cost of TC pile; (2) The bending properties of PVC tube is better than that of HDPE, which makes the TC pile construction speed faster.
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Geotech Geol Eng (2013) 31:1359–1368 (1)
(2)
(3)
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Pile cap Pulley
Inserted steel bars
Steel casing
Rope Water inlet
Hook Pouring water
Tube joint TC casing
Casting concrete
Single-walled PVC
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