滨海软土区地铁轨道过渡段PHDC桩网结构路基参数优化分析  

Parameter Optimization Analysis of PHDC Pile Net Structure Subgrade in Metro Track Transition Section in Coastal Soft Soil Area

作　　者：安志强 王小军 金展潇[3] AN Zhiqiang;WANG Xiaojun;JIN Zhanxiao(School of Civil Engineering,Chongqing Jiaotong University,Chongqing 400074,China;Ningbotech University,Ningbo Zhejiang 315100,China;Zhejiang Zhongjiao Tongli Engineering Design Co.Ltd.,Hangzhou 310011,China)

机构地区：[1]重庆交通大学土木工程学院,重庆400074 [2]浙大宁波理工学院,浙江宁波315100 [3]浙江中交通力工程设计有限公司,杭州310011

出　　处：《铁道建筑》2022年第5期148-151,159,共5页Railway Engineering

基　　金：浙大宁波理工学院横向科研项目(20201229HK0352)。

摘　　要：滨海软土区地铁无砟轨道与有砟轨道过渡段采用PHDC(预应力高强混凝土竹节)桩网结构路基。本文通过理论计算和数值模拟分析了桩长、桩径、桩体刚度、桩帽尺寸及桩间距对过渡段路基沉降的影响。结果表明:原设计中的桩长25 m可优化为20 m;桩径在300~500 mm、桩体刚度在32.5~38.0 GPa、桩帽边长在1.4~1.8 m时,其对过渡段路基沉降的影响较小;由于路基底部碎石垫层夹土工格栅的调节作用,不同影响因素下路基顶面沉降均呈线性变化;纵向减少一排桩后,路基底面沉降、桩土差异沉降、桩间土沉降均略有增大,路基顶面平均沉降仅增加约2.5 mm,远小于10 cm的规范限值,因此建议该工程把桩间距由2.0、2.5、3.0 m增大为3.0、4.5 m。PHDC(prestressed high-strength concrete nodular)pile net structure subgrade is adopted for the transition section between ballastless track and ballasted track of metro in coastal soft soil area.Through theoretical calculation and numerical simulation,the effects of pile length,pile diameter,pile stiffness,pile cap size and pile spacing on the subgrade settlement in the transition section were analyzed in this paper.The results show that the pile length in the original design is 25 m,which can be optimized to 20 m.When the pile diameter is 300~500 mm,the pile stiffness is 32.5~38.0 GPa,and the side length of the pile cap is 1.4~1.8 m,it has little effect on the subgrade settlement of the transition section.Due to the adjustment of gravel cushion with geogrid at the subgrade base,the settlement of subgrade top surface changes linearly under different influencing factors.After reducing a row of piles longitudinally,the settlement of subgrade bottom,differential settlement of pile-soil and settlement of soil between piles increase slightly,and the average settlement of subgrade top only increases by about 2.5 mm,which is far less than the specification limit of 10 cm.Therefore,it is suggested to increase the pile spacing from 2.0,2.5 and 3.0 m to 3.0 and 4.5 m.

关 键 词：铁路路基 桩网结构 数值模拟 沉降 滨海软土区 过渡段 参数优化 PHDC 

分 类 号：U416.1[交通运输工程—道路与铁道工程]