www.seipub.org/ce Construction Engineering Volume 4, 2016 doi: 10.14355/ce.2016.04.005
The Influence Analysis of Pile‐driver to Embankment Piles Zhou Ziyan1, Zhou Qi2, Yuan Yulu3, Li Qian3, Zhou Xingde3† 1. Wentian College, Hohai University, Maanshan 243031, PR China; 2. Zhaoqing University, Zhaoqing, 526061, PR China; 3. College of Civil and Transportation Engineering, Hohai University, Nanjing 210098, PR China Email: Xingdezhou@hhu.edu.cn
†
Abstract Aimed at the piles deformation produced by the weight of pile‐driver, both bearing capacity and line‐type of joint‐method‐pile are studied by combining finite element with experiment data. We can acquire by simulated analysis: the line‐type of pile is closely related to corresponding soils properties, and the bigger deformation of pile is located at soft soil layers; the more closer of the distance between pile and pile‐driver, the smaller of pile bearing capacity; related to vertical pile, the maximally reducing ratio of bearing capacity of deformed pile is 32.4 percent. In the paper, a 4.2m lower limit of horizontal distance between pile and pile driver is suggested in order to increase the pile bearing capacity. Key words Joint‐method‐pile; Pile‐driver; Bearing Capacity; Line‐type
Introduction With the rapid development of expressway in our country, the research on composite foundation has become popular, and many studies have been developed, such as analytical solution for consolidation of composite ground with impervious pile[1], correction about settlement calculation method of CFG pile composite foundation[2], bearing behavior of column‐soil‐cushion mutual action in composite foundation with rammed cement‐soil column[3], etc. Most of the studies are based on the assumption of vertical piles, few of them are based on the inclined pile. The inclined pile may be set [4‐5] for some special purposes. The inclination of the pile should be reduced under normal circumstances to avoid influencing the bearing capacity of composite foundation. There are still less studies on the related filed, and relatively, bearing properties analysis is studied only according to the ideal inclination [6‐7], and does not take into account the actual deformation of pile body. Embankment pile is a kind of flexible pile. The age of concrete is short, the deformation module is small, and the soft soil is elastic‐plastic material. Because of this, the shape of the pile is a curve, and its line‐type and soil properties are closely related to the weight of the pile‐driver. For a particular soil, pile‐driver has a great influence on the line‐type of the pile, because that these devices are usually of more than 20t, and are close to the pile. Age is very important for the concrete properties. The existing studies emphasize particularly on the research on the later period [8‐9]. For the early age, Yang put forward the change model of the compressive strength and modulus of elasticity [10]. Based on the practical engineering, this paper takes the new embankment pile ‐ joint method that proposed by the author as an object, and studies the influence on the line‐type and the bearing capacity from the pile‐driver by combining with the experiment on the bearing capacity of the pile [11]. Change Model of the Concrete Early-age Elastic Modulus The change model of the concrete early‐age elastic modulus can be fitted according to the experimental date [10], and the model is as following:
0.034t 0.028 [1 (C 40)( 0.01)]Ec (1) 0.07 0.0315t t Where t is the age and C is the concrete strength grade. Assuming that 0 t 28 and 30 C 60 . Assuming Ec E
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