承压水降压引起的高速铁路桥梁摩擦型群桩沉降特性分析  

Analysis of Settlement Characteristics of Friction Pile Groups of High Speed Railway Bridge Caused by Pressure Drop of Confined Water

作　　者：张超 ZHANG Chao(China Railway First Survey&Design Institute Group Co.Ltd.,Xi’an 710043,China)

机构地区：[1]中铁第一勘察设计院集团有限公司,西安710043

出　　处：《铁道建筑》2021年第6期36-40,共5页Railway Engineering

摘　　要：以沪宁城际铁路一座特大桥摩擦型群桩基础工程为背景,采用室内三轴试验、有限元数值模拟等手段,对承压水降压引起的土层压缩性变化规律、群桩基础沉降及受力特征进行了分析。研究结果表明:饱和粉土弹性模量增长倍数与土体孔隙水压力下降百分比呈指数递增关系;承压水降压对角桩影响最大,边桩次之,中心桩所受影响最小;承压水降压使群桩基础出现了明显的附加沉降及负摩阻力,且承压水水头降深越大,负向摩阻力的作用范围越大,桩身附加轴力越大。Based on the friction pile group foundation engineering of a super-large bridge on Shanghai-Nanjing intercity railway,the change rule of soil compressibility,settlement and stress characteristics of pile group foundation caused by pressure drop of confined water were analyzed by means of indoor triaxial test and finite element numerical simulation.The results show that the increasing multiple of elastic modulus of saturated silt increases exponentially with the decreasing percentage of pore water pressure.The pressure drop of confined water has the greatest impact on the diagonal pile,followed by the side pile and the center pile.The pressure drop of confined water can cause the obvious additional settlement and negative friction of pile group foundation.The greater the water head drop of confined water,the larger the acting range of negative friction and the greater the additional axial force of pile body.

关 键 词：高速铁路桥梁 摩擦型群桩 承压水 三轴试验 数值模拟 附加沉降 负摩阻力 

分 类 号：TU753.66[建筑科学—建筑技术科学]