摘要
为研究PFWD冲击荷载对道路结构层的影响深度,提出合理的PFWD检测试验参数配置,首先分析PFWD最大荷载的影响参数,提出应力余量θ作为应力衰减量的指标,根据刚性承载板下弹性半空间体应力解,建立单层结构应力衰减与深度和板半径的关系;然后,建立刚性承载板下双层结构的有限元模型,研究层厚、板半径、结构层模量和泊松比对应力深度衰减的影响,建立了应力余量θ与模量比(E1/E0)和层厚(H1/δ)的关系;最后,按应力衰减至绝对水平定义了影响深度.研究结果表明:锤重、落高和承载板半径等参数影响PFWD最大荷载;单层结构中应力衰减量只取决于深度与板半径比值;随着上层模量增大,应力加速衰减;随着下层模量增大,应力衰减延缓;上下层模量比E1/E0对双层结构应力衰减有影响;泊松比几乎不影响应力衰减;不同PFWD配置下(锤重、承载板)有不同的影响深度,结合理论分析结果和工程实际,按照被检测层与下承层的模量比(E1/E0)提出了合理的参数配置.
This research focused on the action depth of portable falling weight deflectometer(PFWD) impact load on road structure and proposed reasonable testing parameters for PFWD. Influence parameters of PFWD maximum load were analyzed and stress allowance θ was proposed as an index of stress attenuation. According to the stress solution of elastic half-space under rigid bearing plate, the relationship between θ and depth and radius of single-layer structure was established. Then the finite element model of double-layer structure under rigid bearing plate was built to analyze the effects of thickness, radius, modulus, and Poisson’s ratio on the vertical stress, and the relationship between θ and modulus ratio and thickness was established. The action depth was defined as the depth at which the stress decreases to a certain value. Results show that parameters such as the weight, height of the hammer, and the radius of the plate have effects on the maximum load. The degree of stress attenuation in a single layer structure depends only on the ratio of depth to plate radius. Stress attenuation becomes faster with the increase of the upper layer modulus, while it slows down with the increase of underlying layer modulus. Poisson’s ratio almost has no effect on the stress attenuation. The action depth of PFWD is different with different configurations(hammer weight, plate radius), which is recommended in accordance with analysis result and engineering practice, and reasonable parameters configuration was then proposed based on the stiffness ratio of the tested layer and the underlying layer.
作者
王龙
夏浩然
WANG Long;XIA Haoran(School of Transportation Science and Engineering,Harbin Institute of Technology,Harbin 150090,China)
出处
《哈尔滨工业大学学报》
EI
CAS
CSCD
北大核心
2019年第9期62-67,共6页
Journal of Harbin Institute of Technology
关键词
道路工程
半刚性基层
PFWD
应力余量
影响深度
配置参数
highway engineering
semi rigid base
PFWD
stress attenuation
action depth
configuration parameters
