摘要
为研究车辆荷载作用下水泥混凝土路面板底脱空区内动水压力、水流速度的分布规律及其影响因素,推导了三维状态下脱空区中截面动水压力、水流速度解析式。应用有限元软件ANSYS和CFX建立了双向流固耦合模型,分析了车辆轴重、车速与脱空尺寸等对动水压力及水流速度的影响。结果表明:固定点的水压力及水流速度随时间成正弦函数变化,且水压力随时间的变化趋势与最大水流速度随时间变化趋势有一定的相位差。沿着脱空区出口的方向,动水压力呈减小趋势,其最大值发生在脱空区尖端;水流速度沿着脱空区出口的方向呈增大趋势,其最大值发生在板边缘;动水压力与水流速度峰值随轴重增大而增大,与轴重近似呈二次方关系;动水压力峰值随车速增大而增大,水压力随车速变化的增幅大约为每10 km/h增加1 kPa,与车速成线性关系,而水流速度峰值受车速影响较小;动水压力与水流速度峰值随脱空区开口量增大而减小,与脱空区开口量成反比关系;当脱空区开口高度扩展到一定程度时(论文模型中为>4 mm),动水压力变化幅值较小,此时脱空区继续发展可能归因于水流的冲刷作用。数值模拟结果与理论推导结果基本一致。
In order to study the distribution rules and influencing factors of dynamic water pressure and flow velocity in the void area bveneath cement concrete slab under vehicle load, the analytical expressions of the dynamic water pressure and flow velocity in the middle section of the void area under 3 D state are derived. The bidirectional fluid-solid interaction model is established by using finite element softwares ANSYS and CFX, and the influences of vehicle axle load, vehicle speed and void size on hydrodynamic pressure and flow velocity are analyzed. The result shows that(1) the water pressure and flow velocity at the fixed point change in a sinusoidal function with time, and there is a certain phase difference between the variation trend of water pressure with time and the variation trend of maximum flow velocity with time;(2) along the direction of the exit of the void area, the hydrodynamic pressure decreases, and the maximum value occurs at the tip of the void area;(3)the flow velocity increases along the exit of the void area, and its maximum value occurs at the edge of the slab;(4) the peak values of hydrodynamic pressure and flow velocity increase with the increase of axle load and has a quadratic relationship with axle load;(5) the peak value of hydrodynamic pressure increases with the increase of vehicle speed, and the increment of water pressure with the change of vehicle speed is about 1 kPa per 10 km/h, which is linear with the speed, but the peak value of flow velocity is less affected by the speed;(6) the peak values of hydrodynamic pressure and flow velocity decrease with the increase of the opening amount in the void area, and they are inversely proportional to the opening amount in the void area;(7) when the opening height of the void area extends to a certain extent(> 4 mm in the proposed model), the variation amplitude of hydrodynamic pressure is smaller, and the continued development of the void area may be attributed to the water flow scouring at this time. The numerical simulation result is
作者
曾晓辉
刘海川
兰旭丽
朱华胜
李颖洁
ZENG Xiao-hui;LIU Hai-chuan;LAN Xu-li;ZHU Hua-sheng;LI Ying-jie(School of Civil Engineering,Central South University,Changsha Hunan 410075,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu Sichuan 610031,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2020年第3期1-8,共8页
Journal of Highway and Transportation Research and Development
基金
“十三五”重点研发计划项目(2016YFB0303603)
高铁联合基金项目(U1534207)。
关键词
道路工程
动水压力
流固耦合
板底脱空
裂纹尖端
road engineering
hydrodynamic pressure
fluid-solid coupling
void beneath slab
crack tip
