【摘要】 在深季节冻土区,涵洞的存在使其基础的冻结深度大于天然场地冻结深度,前者约为后者的2倍,工程中一般将铺设隔热层作为解决方法。本文通过等效厚度换算法比较现阶段3种常用隔热材料的优缺点;以哈大高速铁路上的试验涵洞为原型,运用有限元分析方法,对深季节冻土区涵底有隔热层涵洞的温度场进行数值模拟;为检验隔热层效果,改变隔热层铺设的位置、方式和厚度,分别进行数值计算,了解各因素对涵底冻深的影响,得到适合涵洞基础的最佳隔热层铺设方案。结果表明:泡沫混凝土是涵底隔热层的理想材料,针对试验涵洞,应在基础最上端铺设厚度38cm、比基础宽10cm的泡沫混凝土作为隔热层,这样可以减少涵底最大冻结深度,满足寒区工程需要。更多还原

【Abstract】 In deep seasonally frozen region,the culvert changed the freezing process.The maximum depth of seasonal freezing in culvert foundation was about 2times deeper than that in natural ground.In order to ease the situation,the measure of laying thermal-protective coating under the culvert is usually taken as a solution.In this paper,the advantages and disadvantages of three kinds of commonly used insulation materials were compared through the equivalent thickness conversion method.Based on the existing monitoring data of the culverts in Harbin to Dalian passenger dedicated line,a finite element model was established to simulate the temperature fields of the culverts with thermal-protective coating.To verify the effect of the thermal-protective coating,a numerical calculation was conducted respectively on different locations,modes and thickness of the thermal-protective coating to understand the influence of different conditions on the maximum frozen depth and to obtain the optimal laying scheme for culvert foundation.The results indicated that foam concrete is the ideal material for the thermal-protective coating,and the 38-cm-thick foam concrete should be laid on the top of the experimental culvert foundation as thermal-protective coating,which should be 10 cm broader than the foundation.In this way,the maximum freezing depth under the culvert could be reduced,to meet the needs of construction in the cold region.更多还原