摘要
介绍了一种全比尺的高速铁路加速试验装置,以重现轮轴移动荷载下轨道路基的动力响应和长期性能。根据列车移动过程中扣件承受荷载的模拟要求,提出高速铁路路基加速试验的设计准则。在此基础上自行建造完成时序式动力加载系统,由8个动态液压激振器、1套控制系统和1套反力框架构成,在室内实现最高速度360km/h列车移动荷载的有效模拟。同时在室内建设完成1∶1比尺的I型板式轨道-路基模型,通过控制填料级配、目标密度和目标含水量来保证路基的压实系数、地基系数和变形模量等指标满足规范的设计要求。前期试验表明,随着列车荷载的逐层传递,其叠加效应愈加显著。轨道结构荷载峰值对应列车轮轴,路基动土压力峰值对应列车转向架。路基横断面方向,基床顶面的动土压力呈马鞍形分布,两侧应力最大,轨道中心应力最小;地基顶面的动应力分布较为均匀。路基土体应力-变形呈现出明显的滞回特征,从长期加载过程看,土体残余变形逐渐累积,表现出明显的塑性特征;但对于每一次加卸载过程,土体的应力-应变可近似为非线性弹性行为。
The design criteria for the testing facility was proposed based on the simulation demand of fastener loads. A sequential dynamic loading system, composed of eight hydraulic actuators, one set of control system and one set of reaction frame, was developed to simulate moving train loads with speeds up to 360km/h. Meanwhile, a 1：1 scale slab track-subgrade system was established in a physical model box. The compaction indices, such as compaction coefficient, foundation coefficient and deformation modulus, were satisfied by controlling the grain composition, desired density and moisture content. Preliminary experimental results showed that superposition effect of stresses became more obvious as the train load transferred from the track structure to the subgrad to the positions of train axles, while those at the subgrade e. The peak stress at the was corresponded to the track structure was corresponded positions of train bogies. The distribution of dynamic soil stresses at the roadbed surface resembled the saddle shape, where the stresses at the corner were the largest and the center lowest, while stresses distributed uniformly at the subsoil surface. The stress-deformation relationship of loading cycles, law. subgrade soil shaped typical hysteretic loops. Although residual deformation accumulated with long-term the short-term reversible behavior of subgrade soils could be described as a non-linear elastic constitutive law.
出处
《土木工程学报》
EI
CSCD
北大核心
2015年第9期85-95,共11页
China Civil Engineering Journal
基金
国家自然科学基金(51178418
51222803)
关键词
高速铁路
全比尺加速试验
时序式动力加载系统
动土压力
应力-变形滞回曲线
high-speed railway
full-scale accelerated testing
sequential loading system
dynamic soil stress
stressdeformation hysteretic curve
