吉林大学学报(工学版) ›› 2020, Vol. 50 ›› Issue (2): 621-630.doi: 10.13229/j.cnki.jdxbgxb20181130

• 交通运输工程·土木工程 • 上一篇    

高铁站场宽路基复合地基二维模型适用性分析

李阳1,2(),王连俊1,2()   

  1. 1.北京交通大学 土木建筑工程学院,北京 100044
    2.北京交通大学 轨道工程北京市重点实验室,北京 100044
  • 收稿日期:2018-11-13 出版日期:2020-03-01 发布日期:2020-03-08
  • 通讯作者: 王连俊 E-mail:liyang6@bjtu.edu.cn;ljwang@bjtu.edu.cn
  • 作者简介:李阳(1989-),男,博士研究生.研究方向:软土地基变形机理及地基处理技术.E-mail:liyang6@bjtu.edu.cn
  • 基金资助:
    教育部中央高校基本科研业务费专项项目(2015YJS120)

Applicability analysis of two dimensional modelingmethods for wide embankment composite foundation in high speed railway stations

Yang LI1,2(),Lian-jun WANG1,2()   

  1. 1.School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China
    2.Beijing Key Laboratory of Track Engineering, Beijing Jiaotong University, Beijing 100044, China
  • Received:2018-11-13 Online:2020-03-01 Published:2020-03-08
  • Contact: Lian-jun WANG E-mail:liyang6@bjtu.edu.cn;ljwang@bjtu.edu.cn

摘要:

为评价二维建模方法在高速铁路站场宽路基复合地基中的适用性,以京沪高铁济南西站站场路基为例,根据5种方法建立相应二维模型分析复合地基受力及变形特征,并与三维模型计算结果及实测结果进行对比。研究表明:在分析地基沉降、桩土应力和路基坡脚水平位移时,等弹性模量法计算结果精度最高;但在分析地基超静孔隙水压力和边桩弯矩时,所有二维模型结果均不可靠,此时须采用三维模型进行分析。

关键词: 道路与铁道工程, 复合地基, 二维模型, 沉降

Abstract:

Three dimensional (3D) modeling of some complex pile composite foundations in high speed railway can be very complicated and time-consuming. So it is a common way to simplify 3D models into two dimensional (2D) models in current research, however, the applicability of different 2D modeling methods remains unclear. In this research, taking Ji'nanxi station in Beijng-Shanghai high speed railway as an example, five different 2D models are established to study their applicability by comparing the results of 2D models with that of 3D models and site measurement data. The study shows that 2D models can provide acceptable results for the development of settlements, stress of pile and soil, as well as lateral displacements. The method which remains the same elastic module and area replacement ratio yields the best results out of all 2D models. But a 3D model is necessary for the generation and dissipation of excess pore water pressures in foundation and bending moments of pile close to the toe of embankment, because 2D models give incorrect results.

Key words: highway and railway engineering, composite foundation, two dimensional model, settlement

中图分类号: 

  • U213.1

图1

地基处理方案及监测方案示意图"

图2

地基处理方案及监测方案示意图"

图3

复合地基二维建模方法"

图4

复合地基单元模型俯视图"

表1

连续墙计算参数"

方法原桩型为CFG桩原桩型为PHC桩
dw/mEw/GPadw/mEw/GPa
恒定参数法0.5025.500.0839.20
等弹性模量法0.1325.500.0239.20
等桩径法0.506.690.083.17
等抗压刚度法0.503.770.085.15
等抗弯刚度法0.502.110.080.81

表2

实体单元模型参数"

材料名称重度γ/(kN·m-3弹性模量E/MPa泊松比υ粘聚力c/kPa内摩擦角φ/(°)渗透系数k/(cm·s-1
粉质粘土19.5150.314518.58×10-5
细砂19.0300.281532.03×10-3
粘土19.5210.354021.02×10-6
卵石21.8800.301045.05×10-3
碎石垫层22.01000.22045.04×10-1
筏板25.030 0000.15---
桩(连续墙)25.0见表10.15---

表3

土工格栅参数"

参数
弹性模量E/GPA67
泊松比υ0.33
厚度t/mm5
耦合弹簧单位面积上刚度K/(N·m-32.3×106
耦合弹簧内聚力c/kPa0

图5

高速铁路站场宽路堤三维模型结构示意图"

图6

桩顶沉降的计算和实测结果"

表4

监测期结束时沉降的计算值和实测值"

方法桩A/mm桩B/mm
桩顶桩间土桩顶桩间土
恒定参数法49.642.257.544.8
等弹性模量法60.548.468.755.4
等桩径法53.343.260.146.7
等抗压刚度法52.045.262.947.3
等抗弯刚度法57.244.263.648.2
三维模型63.849.271.155.7
实测结果60.452.274.661.2

图7

桩间土沉降的计算和实测结果"

图8

桩A桩土应力比的计算和实测结果"

图9

桩B桩土应力比的计算和实测结果"

表5

监测期结束时计算和实测的桩土应力值"

方法桩A桩B
桩顶应力/kPa桩间土平均压力/kPa桩土应力比桩顶应力/kPa桩间土平均压力/kPa桩土应力比
实测3 126.044.170.9872.288.59.9
三维模型3 282.335.193.5921.193.89.8
恒定参数法2 269.025.788.4656.972.49.1
等弹性模量法3 446.433.3103.4884.290.09.8
等桩径法2 067.824.484.8684.273.99.3
等抗压刚度法2 378.028.284.2732.178.99.3
等抗弯刚度法2 171.229.573.7704.881.18.7

图10

桩A底部下方9 m处超静孔隙水压力计算和实测结果"

图11

桩B底部下方21 m处超静孔隙水压力计算和实测结果"

图12

边桩水平位移计算结果"

图13

边桩桩身弯矩计算结果"

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