摘要
为探索高速公路交通荷载与降雨环境耦合作用下低路堤复杂的动力特性及长期性能保障技术措施,依托浙江省某低路堤高速公路为工程背景,结合现场埋深元件测试获取动应力、加速度、动位移等数据,分析了不同轴重和车速等条件下路基的动力特性差异,具体包括动力指标量值和竖向影响深度;考虑降雨环境对高速公路服役期路基动力特性影响,借助ABAQUS有限元分析软件建立"降雨环境-交通荷载-路基"三维数值模型,分析了降雨强度对路基服役期动力特性影响,具体包括中雨(1.25 mm/h)、大雨(2.5 mm/h)和大暴雨(10 mm/h)3类工况;考虑平原水网区低路堤高速公路受交通荷载和降雨环境长期耦合作用,结合路基填料设计、排水系统优化等角度,探讨了保障低路堤路基长期动力稳定性能的技术措施。结果表明:不同荷载条件下路基动应力、加速度和动位移存在差异,但沿路基深度均呈衰减趋势;动应力幅值与轴重成正相关,轴重20 t车辆的动应力幅值约为50 k Pa,约为轴重<5 t车辆的动应力幅值的7~10倍;相对轴重>10 t车辆荷载条件下,速度对动位移影响更大,轴重20 t车辆荷载条件对应动位移约0.60~1.02 mm;相比干燥路基状态,中雨、大雨和大暴雨降雨强度下路基动应力值提高约为3%~15%;合理路基填料设计可以提高低路堤刚度和强度,而完善的排水系统可降低交通荷载与降雨叠加引起的动力响应程度,均可在一定程度达到保障低路堤长期动力稳定的目的。
In order to explore the coupling effect of expressway traffic load and rainfall environment on low embankment complex dynamic characteristics and long-term performance technical protection measures, relying on a low embankment expressway in Zhejiang Province as the engineering background, the stress, acceleration and dynamic displacement are obtained by field depth component test, and the difference of the dynamic characteristics of subgrade under different axle loads and speeds, etc. are analyzed, including dynamic index value and vertical effect depth. Considering the influence of rainfall environment on the dynamic characteristics of expressway subgrade service period, the 3D numerical model of " rainfall environment and traffic load and subgrade" is established using ABAQUS finite element analysis software, and the influence of rainfall intensity on the dynamic characteristics of expressway, including moderate rain (1.25 mm/h), heavy rain (2. 5 mm/h) and heavy downpour ( 10 mm/h), is analyzed. Considering the long-term coupling action of traffic load and rainfall environment on the low embankment expressway in riverine plain area, combining with the design of subgrade filling and drainage system optimization, thetechnical measures for ensuring long-term dynamic stability of low embankment subgrade are discussed. The result shows that ( 1 ) under different loading conditions, dynamic stress, acceleration and displacement of the subgrade are different, but the depth along subgrade has the attenuation trend; (2) the dynamic stress amplitude is positively correlated with axle load, the dynamic stress amplitude of 20 t axle load vehicle is about 50 kPa, about 7 - 10 times of that of 〈5 t axle load vehicle; (3) under relative axle load 〉 10 t vehicle load condition, the speed has larger influence on dynamic displacement, 20 t axle load condition corresponding to the dynamic displacement of about 0.60 - 1.02 mm; (4) comparing with the dry subgrade state, the dynamic displacement of subgrade under moderate rain, heavy rain and heavy intensities increased by about 3% - 15% ; (5) the design of reasonable subgrade filler can improve the stiffness and strength of low embankment, perfect drainage system can reduce the dynamic response caused by traffic load and rainfall to guarantee the long-term dynamic stability of low embankment to some degree.
出处
《公路交通科技》
CAS
CSCD
北大核心
2018年第2期33-40,47,共9页
Journal of Highway and Transportation Research and Development
基金
国家自然科学基金项目(51078358)
高铁联合基金重点项目(U1134207)
铁道部科技研究开发计划项目(2012G009C)
关键词
道路工程
动力特性
现场测试
低路堤
高速公路
road engineering
dynamic characteristics
field test
low embankment
expressway