高铁复合结构路基荷载传递及沉降数值模拟  

Numerical Research on the Load Transfer and Settlement of Composite Structural Subgrade of High-speed Railway

作　　者：吕玺琳[1] 马泉 LV Xi-lin;MA Quan(Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai 200092,China;Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学岩土及地下工程教育部重点实验室,上海200092 [2]同济大学,上海200092

出　　处：《铁道工程学报》2018年第7期1-6,共6页Journal of Railway Engineering Society

基　　金：国家重点基础研究发展计划(973)青年科学家专题项目(2014CB049100)

摘　　要：研究目的:高速列车运营荷载作用将导致复合结构路基产生沉降。由于高铁对路基沉降要求高,复合结构路基的荷载传递和沉降变形规律值得工程界关注。为研究高铁复合结构路基荷载传递以及沉降变形规律的影响因素,本文建立高速铁路复合结构软土路基三维有限元分析模型,将高速铁路列车运行荷载简化为均布荷载作用于轨道板以下的路堤顶面,分析桩长、桩间土模量和下卧层模量对桩身轴力分布、桩土应力比以及路基沉降的影响规律。研究结论:(1)桩身轴力随桩长增加而增大,路基沉降则明显减小;在不同桩长下,桩土应力比沿桩身距离路基中心水平方向位置的变化均表现为先增大再减小的趋势,10 m、12.5 m、15 m和20 m桩长下桩土应力比稳定值分别为6.8、10、13和17;(2)桩身轴力随桩间土模量增大而减小;在不同桩间土模量下,桩土应力比随桩身距路基中心水平位置的偏移先稳定后增大再减小,10 MPa、30 MPa和50 MPa桩间土模量下桩土应力比分别为30、12和7;(3)下卧层模量增大使桩端摩阻力增大,桩身中性点位置向下偏移;桩土应力比随水平位置偏移的变化规律同样是先增大后减小,下卧层模量增大能使桩的沉降明显减小,但对路基总沉降影响不大;(4)该研究结论可为高铁复合结构路基及类似工程设计和施工提供理论参考。Research purposes： The composite structure subgrade for high-speed railway will produce settlement under train loading. Since the high-speed railway has a strict requirement for settlement,the load transfer rule and settlement of composite structure subgrade are widely concerned in engineering field. To investigate the influence factors of settlement and the load transfer rule of high-speed railway composite structure subgrade,the 3D finite element model of the rigid pile reinforced subgrade of high-speed railway was established,and the dynamic loading caused by high-speed railway trains was simplified as an uniformly distributed load applied on the subgrade below the rail track. The influence of pile length,modulus of the soil between piles and substratum on the axial force distribution,stress ratio of pile-soil and subgrade settlement was investigated.Research conclusions：（ 1） With the increase of pile length,the axial force of pile increases,and the subgrade settlement decreases obviously; under different pile length condition, the stress ratio shows an increasing and a subsequent decreasing trend with the pile location being away from the subgrade center,when the pile length is 10 m,12. 5 m,15 m and 20 m,the stable value of stress ratio is 6. 8,10,13 and 17,respectively.（ 2） With the increase ofthe modulus of the soil between piles,the axial force of piles decreases; the stress ratio also shows an increasing and subsequent decreasing trend with the pile location being away from the subgrade center,when the modulus is 10 MPa,30 MPa and 50 MPa,the stable value of stress ratio is 30,12 and 7,respectively.（ 3） Due to the increase in the modulus of substratum,the friction resistance of piles tip increases,and the position of neutral point of piles descends;the stress ratio also shows an increasing and subsequent decreasing trend with the pile location being away from the subgrade center,the increase in the modulus of the substratum is useful for controlling pile top settlement but useless for reduc

关 键 词：高铁 复合结构路基 沉降 数值模拟 桩土应力比 

分 类 号：TU472[建筑科学—结构工程]