考虑雨水感热作用的降雨对多年冻土路基水热影响模型试验  

Model Test Research on Influence of Rainfall Considering Rainwater Sensible Heat on Hydrothermal State of Permafrost Subgrade

作　　者：张明礼[1,2,3] 雷兵兵 周志雄 周凤玺 侯彦东[1] ZHANG Ming-li;LEI Bing-bing;ZHOU Zhi-xiong;ZHOU Feng-xi;HOU Yan-dong(College of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,Gansu,China;Western Engineering Research Center of Disaster Mitigation in Civil Engineering of Ministry of Education,Lanzhou University of Technology,Lanzhou 730050,Gansu,China;School of Earth Science and Engineering,Nanjing University,Nanjing 210023,Jiangsu,China)

机构地区：[1]兰州理工大学土木工程学院,甘肃兰州730050 [2]兰州理工大学西部土木工程防灾减灾教育部工程研究中心,甘肃兰州730050 [3]南京大学地球科学与工程学院,江苏南京210023

出　　处：《中国公路学报》2024年第7期112-124,共13页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(41961010,42261028,41801033);中科院西部之光“西部青年学者”项目(23JR6KA027);陇原青年创新创业人才(个人)项目(2023LQGR18)。

摘　　要：为探究雨水感热作用下的降雨对多年冻土路基稳定性的影响,参照青藏高原北麓河地区的环境特点和多年冻土路基结构,通过底板-大气双控温室内模型箱开展了多年冻土区沥青路面路基模型试验,考虑了环境潜在雨水温度导致的雨水感热能量脉冲作用,分析了多周期不同降雨工况下的路面温度与辐射、路基含水量、热通量和温度响应。结果表明:多年冻土环境中雨水温度与气温在夏季差异显著,最大温差近3℃,在春秋季差异小于1℃;受雨水感热的影响,夏季降雨引起路面温度、地表向上辐射通量和浅层土壤热通量显著降低,导致的路基降温效果从强到弱为路面、路肩、边坡、天然场地,降幅与降雨量正相关;秋季降雨对路基土体降温效果较弱,春季降雨促进路面与路肩下土体热通量和温度的降低,而易引起边坡和天然场地土体的升温;同样,多年冻土路基活动层水分变化表现出相似的季节特征,但含水量增量从大到小为路肩、边坡、天然场地、沥青路面,降雨对路面下土体含水量的影响深度(大于0.25 m)小于路肩(小于0.35 m)。因此,在降雨入渗深度范围内,多年冻土路基不同深度土体周期性平均降温从大到小为路肩、边坡、天然场地,沥青路面下土体仅在浅层0.05~0.15 m降温显著;忽略雨水感热作用时低估了降雨对路面长波辐射和路面温度的降低作用,高估了水分累积量,路面下降温效果减弱,从而导致路肩、边坡和天然场地出现升温。This study considered the environmental characteristics and permafrost subgrade structure of the Beiluhe area in the Qinghai-Tibet Plateau.The goal was to explore the impacts of rainfall on the stability of the permafrost subgrade under the effect of the rainwater sensible heat.Based on an indoor simulation chamber with dual-temperature control for the bottom plate and atmosphere,asphalt pavement subgrade model tests were conducted for the permafrost areas.The energy pulse effect of the rainwater sensible heat owing to the environmental potential rainwater temperature was considered.The pavement temperature and radiation,subgrade moisture content,heat flux,and temperature response were analyzed under different rainfall conditions and multiple cycles.The results show that a significant temperature difference exists between the rainwater and air in the permafrost environment in summer.The maximum temperature difference is nearly 3℃and the difference is less than 1℃in spring and autumn.Influenced by the rainwater sensible heat,the summer rainfall significantly reduces the pavement temperature,surface upward radiation flux,and shallow soil heat flux.The subgrade cooling effects caused by the rainfall rank in the order of pavement>shoulder>slope>natural ground and the reduction is positively related to the rainfall.The cooling effect of the autumn rainfall on the permafrost subgrade soil is weakened.The spring rainfall promotes reductions of the soil heat flux and temperature under the pavement and shoulders but causes the temperature to increase in the slope and natural ground.The moisture change of the permafrost subgrade active layer shows similar seasonal characteristics;however,the water content increments rank in the order of shoulder>slope>natural ground>asphalt pavement.The depth of the influence of the rainfall on the soil moisture content under the pavement(<0.25 m)is smaller than that on the shoulder(>0.35 m).Therefore,the periodic average temperature drops of the permafrost subgrade soil in the range o

关 键 词：路基工程 水热响应 模型试验 降雨过程 多年冻土 雨水感热 

分 类 号：U419.92[交通运输工程—道路与铁道工程]