Calculation Method of Negative Skin Friction of Railway Bridge Cast-in-Situ Pile in Large Thickness Collapsible Loess Area

被引：0
|
作者：
Zhang Y. [1 ]
Yang C. [1 ]
Wang X. [1 ,2 ]
Yang S. [3 ]
Jiang D. [1 ]
机构：
[1] School of Civil Engineering, Lanzhou Jiaotong University, Gansu, Lanzhou
[2] National and Provincial Joint Engineering Laboratory of Road & Bridge Disaster Prevention and Control, Gansu, Lanzhou
[3] China Railway First Survey and Design Institute Group Ltd, Shaanxi, Xi'an
来源：
Zhongguo Tiedao Kexue/China Railway Science | 2023年 / 44卷 / 05期
关键词：
Cast-in-situ pile; Collapsible loess; Negative skin friction; Pile foundation; Railway bridge;
D O I：
10.3969/j.issn.1001-4632.2023.05.10
中图分类号：
学科分类号：
摘要：
When the pile foundation of a railway bridge crosses large thickness collapsible loess site, the reasonable value and calculation of negative skin friction and neutral point depth of pile foundation are key engineering challenges that need to be resolved at present. In view of the shortcomings of the current specifications, based on the analysis and summary of the immersion test results of the pile foundation on the collapsible loess site, parabola is used to fit the distribution of negative skin friction when it reaches a stable state, and the parameters such as the depth ratio of the neutral point, the depth of the maximum negative friction, the maximum and the average values of negative skin friction are analyzed and discussed. According to the mechanical mechanism and distribution mode of negative skin friction, considering the influence of collapsible soil thickness on dynamic friction coefficients, the calculation method of negative skin friction is proposed. The results show that when the pile top bears a certain vertical load before immersion, the neutral point depth ratio determined with the lower limit depth of collapsible loess layer calculated by laboratory test is consistent with the recommended value of the current specification. The depth of the maximum negative friction is about 0. 5 times the depth of the neutral point, and the maximum value of negative skin friction is 1. 5 times of its average value. The average value of negative skin friction calculated by the proposed method is consistent with the recommended value in“Technical Specification for Building Cast-in-Situ Pile Foundations in Collapsible Loess Regions”, which can be used as the characteristic value for calculating the vertical bearing capacity of single pile in large thickness collapsible loess sites. The research results can provide reference for the engineering design of pile foundation in collapsible loess areas. © 2023 Chinese Academy of Railway Sciences. All rights reserved.
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页码：94 / 106
页数：12
相关论文
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