高海拔冻土地区公路路基风流场特征研究  

Characteristics of wind flow field over roadway embankment in high altitude permafrost regions

作　　者：宋正民 马巍 穆彦虎 俞祁浩 谢胜波 刘永智 SONG Zhengmin;MA Wei;MU Yanhu;YU Qihao;XIE Shengbo;LIU Yongzhi(School of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,China;State Key Laboratory of Frozen Soil Engineering,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China;Key Laboratory of Desert and Desertification,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China)

机构地区：[1]兰州理工大学土木工程学院,甘肃兰州730050 [2]中国科学院西北生态环境资源研究院冻土工程国家重点实验室,甘肃兰州730000 [3]中国科学院西北生态环境资源研究院沙漠与沙漠化重点实验室,甘肃兰州730000

出　　处：《冰川冻土》2021年第2期463-473,共11页Journal of Glaciology and Geocryology

基　　金：国家自然科学基金项目(41630636,41772325)资助。

摘　　要：风流场对于局地条件下地-气能量交换过程与强度影响显著,同时也是多年冻土区对流调控类冷却路基的关键环境边界。结合现场监测与数值模拟,对高海拔冻土路基周边风流场进行特征区划研究并考察路基高度的影响。结果表明:坡前扰动区为低风速区,3m路基高度条件下迎风坡坡脚0.5~2.0m高度范围内风速约为环境风速的30%。路基上部为高风速区,迎风坡路肩风速明显大于环境、路面中部及背风坡风速。背风坡坡后扰动区为低风速区,靠近坡脚区域受气流辐散效应作用形成涡旋区,整体风速仅为环境风速的30%。涡旋区水平范围随路基高度增加呈线性增加,3m路基高度条件下涡旋区水平范围约为12m。分离式路基即两幅路基并行条件下,受前幅路基影响后幅路基坡前风速下降明显,以两幅路基坡前风速差值不超过环境风速的10%(0.35m·s^(-1))为标准,3m路基高度条件下两幅路基最小间距为60m。因此,在路基工程的修建过程中为减少路基间的遮挡所造成的两幅路基间的对流换热强度差异,分离式对流换热类冷却路基的现场修建间距应不低于60m。Wind flow has a significant influence on the process and intensity of the ground-air energy exchange,and it is a key environmental boundary for cooled roadway embankment through heat convection adjustment in permafrost zones. Using field monitoring and numerical simulations,characteristics of wind flow field over roadway embankment in high altitude regions were studied and the effect of embankment height was investigated. The results show that the disturbed zone at the front of the windward slope is a zone with low wind speed.The wind speeds within the height from 0.5 to 2.0 m above the natural ground surface at the windward slope foot are only about 30% of the environment wind speed when the embankment thickness is 3 m. Wind speed above the embankment is greater than that of the environment wind speed at the same height. And wind speed at the windward shoulder is obviously greater than that at the center and the leeward shoulder of the embankment.The disturbed zone behind the leeward slope is a zone with low wind speed. And a vortex will develop in the zone near the leeward slope foot. Wind speed of the vortex is generally 30% of the environmental wind speed.The horizontal range of vortex is about 12 m when the embankment thickness is 3 m,and it increases linearly with increase in embankment thickness. For two separated embankments,wind speed around the leeward embankment is obviously smaller than that around the windward embankment. Taking the discrepancy of wind speed at the windward sloop feet of the two embankments not exceeding 10% of the environmental wind speed(0.35 m·s^(-1))as the standard,the minimum spacing between the two embankments is about 60 m with their thickness being 3 m. Therefore,in order to avoid the difference of cooling effect caused by the interaction between the embankments during the construction of embankment works,the site construction spacing of the separated convection heat exchange type cooling subgrade should not be less than 60 m.

关 键 词：公路路基 多年冻土区 风流场 风速 路基高度 

分 类 号：P642.14[天文地球—工程地质学] U411[天文地球—地质矿产勘探]