无砟轨道X形桩–筏复合地基动土压力分布规律试验研究  

Model tests on distribution law of dynamical soil pressure of ballastless track XCC pile-raft composite foundation

作　　者：刘汉龙[1,2,3] 孙广超[2,3] 孔纲强[2,3] 李辉[2,3] LIU Han-long SUN Guang-chao KONG Gang-qiang LI Hui(College of Civil Engineering, Chongqing University, Chongqing, 400450, China Key Laboratory of Geomechanies and Embankment Engineering （Hohai University）, Ministry of Education, Nanjing 210098, China College of Civil and Transportation Engineering, Hohai University, Nanjing 210098, China)

机构地区：[1]重庆大学土木工程学院,重庆400450 [2]河海大学岩土力学与堤坝工程教育部重点实验室,江苏南京210098 [3]河海大学土木与交通学院,江苏南京210098

出　　处：《岩土工程学报》2016年第11期1933-1940,共8页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(U1134207;51278170;51479060);国家自然科学基金重点国际(地区)合作研究项目(51420105013)

摘　　要：基于1∶5的轨道–路基–桩筏复合地基模型,采用能够近似模拟列车单个轮轴荷载的正弦波荷载,在砂土地基中通过开展不同激振频率下无砟轨道X形桩–筏复合地基的动力特性模型试验,研究不同激振频率引起的轨道–路基–桩筏复合地基中的速度和动土压力,测得了速度响应、动土压力随深度和激振频率的变化规律。研究结果表明:在路堤横截面方向上,振动响应主要集中在轨道–路基结构中,基床表层中的动土压力在路堤横截面方向呈"W"形分布,地基表面的动土压力呈"U"形分布。基床表层中的动土压力荷载放大系数随激振频率的增加而逐渐增加。相关研究成果可为无砟轨道X形桩–筏复合地基的理论分析与计算以及动力荷载放大系数的确定提供参考依据。Based on 1：5 scale track-subgrade-pile-raft composite foundation model, the dynamic response of ballastless track X-section cast-in-situ concrete（XCC） pile-raft composite foundation embedded in sand under sine wave loads（which can approximately simulate a train axle load） with different frequencies is investigated. This involves the measurement and analysis of response in velocity and dynamic soil pressure under different load frequencies. It is shown that, in the direction of cross-section of embankment, the velocity response mainly focuses on track-subgrade. The dynamic soil pressure of roadbed is ＂W＂-shaped distribution and the dynamic soil pressure of subsoil surface is ＂U＂-shaped distribution in the direction of cross-section of embankment. The dynamic load magnification factor of roadbed increases with the increasing load frequency. The research results may provide an insight into the theoretical analysis and calculation of ballastless track XCC pile-raft composite foundation, and validating its dynamic load magnification factor.

关 键 词：无砟轨道 桩–筏复合地基 X形桩 动土压力 模型试验 

分 类 号：TU43[建筑科学—岩土工程]