深厚火山灰堆积区高铁桥梁超长桩承载特性试验  

Site Test on Bearing Deformation Characteristics of Super⁃long Piles of High Speed Railway Bridges in Deep Volcanic Ash Area

作　　者：张志国 ZHANG Zhiguo(China Railway Design Group Co.Ltd.,Tianjin 300308,China)

机构地区：[1]中国铁路设计集团有限公司,天津300308

出　　处：《铁道建筑》2025年第2期71-76,共6页Railway Engineering

基　　金：中国铁路设计集团有限公司开发课题(2021A240601)。

摘　　要：火山灰堆积地层的物理力学、水理性质复杂,桩土相互作用规律不清,导致途经该地区的高速铁路桩基承载特性不明。本文依托沈白(沈阳—白河)高速铁路工程,开展深厚火山灰堆积区高铁桥梁超长桩静载试验,分析深厚火山灰堆积区高铁桥梁超长桩的荷载传递规律与承载变形特性。结果表明:试验桩的荷载-沉降曲线整体呈缓变型,属于渐进式破坏,试验容许承载力为6000 kN,远大于设计容许承载力,安全可靠。桩身轴力沿深度逐渐减小,呈倒三角形分布。最大加载条件下,荷载主要由桩身上部、中部的桩侧摩阻力承担,表现为摩擦桩工作特性。摩阻力与桩土相对位移的关系呈硬化型。提出了不同土层桩侧摩阻力设计取值的建议。The physical,mechanical,and hydraulic properties of volcanic ash accumulation strata are complex,and the interaction law between piles and soil is unclear,resulting in uncertain bearing characteristics of high speed railway pile foundations in this area,with limited relevant studies domestically and internationally.This paper conducts static load tests on super-long piles of high speed railway bridges in deep ash accumulation areas based on the Shenyang-Baihe high speed railway project,analyzing the load transfer rules and bearing characteristics of super-long piles in deep ash accumulation areas for high speed railway bridges.The research findings indicate that.The load-settlement curve of the test pile generally exhibits a gradual failure mode,with a permissible bearing capacity of 6000 kN,significantly higher than the design permissible bearing capacity,ensuring safety and reliability.The pile axial force gradually decreases with depth,following an"inverted triangle"distribution.At maximum loading,the load primarily sustained by the friction resistance of the middle and upper section pile body,indicating the working characteristics of friction piles.Pile side resistance increases with the relative displacement between the pile and soil,displaying a hardening characteristic.Proposed design values for the pile side resistance of each soil layer in the volcanic ash accumulation area are provided.These research findings deepen understanding of the bearing deformation characteristics of pile foundations in volcanic ash accumulation areas,offering a basis for the optimal design of pile foundations for high speed railway bridges traversing volcanic ash accumulation layers of silty clay,thereby presenting significant engineering application value.

关 键 词：高速铁路桥梁 承载特性 现场试验 超长桩 火山灰 

分 类 号：U448.13[建筑科学—桥梁与隧道工程]