多年冻土区公路路堤碎石层厚度的计算  

Fractured-rock layer thickness of highway embankment in permafrost regions

作　　者：孙斌祥[1] 徐学祖[1] 赖远明[2] 汪双杰[3] 章金钊[3] 

机构地区：[1]绍兴文理学院土木工程系,浙江绍兴312000 [2]中国科学院寒区旱区环境与工程研究所冻土工程国家重点实验室,甘肃兰州730000 [3]中交第一公路勘察设计研究院,陕西西安710068

出　　处：《岩土工程学报》2006年第4期451-459,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家杰出青年科学基金资助项目(40225001);交通部国家西部交通建设科技项目(200231800004);绍兴文理学院重点学科建设基金资助项目

摘　　要：通过变渗透率多孔介质流函数控制方程,分析了青藏公路碎石路堤冬季自然对流降温效应的发生和演化过程。结果表明:公路碎石路堤冬季自然对流降温效应从边坡区域最先开始形成,并随着冬季路面温度下降而逐渐向路堤中间区域发展。通过引入自然对流指数,分析了自然对流降温效应随路堤碎石层填筑厚度的变化规律,其可分为恒零区、急增区和缓变区3个阶段,急增区的起点和终点对应于路堤碎石层填筑的最小厚度和最大厚度。最后,利用自然对流指数具体计算了不同粒径碎石层填筑的临界厚度。Occurrence and development of winter-time natural convection cooling effect in the fractured-rock embankment of Qinghai-Tibet highway were investigated using the governing equations based on air-flow function for natural convection in porous media with variable permeability. It was shown that winter-time natural convection in the fractured-rock embankment began to occur in the Side slope portions and developed from two side slope portions to the middle portion of embankment with lowering of surface temperature. A natural convection index for representing the cooling effectiveness of winter-time natural convection in the fractured-rock highway embankments was introduced. There were three regions of the variation of the natural convection index with thickness of layer in the highway, i.e., zero region, rapid increase region and no appreciable increase region. Thicknesses of fractured-rock layer in highway embankment corresponding to the initial point and end point of the rapid increase region were defined as the minimum and maximum thicknesses of fractured-rock layer constructed, which triggered winter-time natural convection, respectively. Evaluating fractured-rock layer thicknesses of highway embankment with various grain sizes was performed.

关 键 词：多年冻土 气冷路堤 自然对流 碎石层厚度 青藏公路 

分 类 号：TU445[建筑科学—岩土工程] U213.1[建筑科学—土工工程]