季节性冻土区黏土冻结深度预测

Predicted Frost Depth of Clay in Seasonally Frozen Ground Region

合理确定冻结深度是季节性冻土区防冻设计的关键,为研究季节性冻土区黏土的冻结深度,统计了中国部分季节性冻土地区气温,获得了这些地区的气温特征,以此确定了室内试验的温度边界条件,开展了10%、20%、30%3种不同质量含水量的单向冻融循环试验。研究结果表明,10%、20%、30%3个试样的最大冻结深度分别为28、15、12 cm;鲁基扬诺夫公式预测值较Stephan公式、《建筑地基基础设计规范》公式、《冻土地区建筑地基基础设计规范》与《冻土工程地质勘察规范》公式的预测值更准确;利用未冻水体积含水率修正了《冻土地区建筑地基基础设计规范》的冻结深度计算值,其误差在6%之内,因而建议在季节性冻土区的黏土地区用该修正公式计算设计冻结深度。

To confirm reasonable frost depth is the key factor of anti-freezing design in seasonally frozen ground region and obtain the frost depth of clay in seasonally frozen ground region,lots of air temperature data were collected from seasonally frozen ground regions in China.Based on the temperature characteristics of these areas,the temperature boundary condition of the laboratory experiment was determined.The one-way freeze-thaw cycling experiment of three different water contents which were 10%,20%,30%respectively was carried out.The results showed that the maximum frost depths of them were 28,15 and 12 cm respectively.The predicted frost depth of Rukiyanov formula was more accurate than Stephan formula,formula of Code for design of building foundation,formula of Code for design of soil and foundation of building in frozen soil region and formula of Code for engineering geological investigation of frozen ground.The predicted frost depth of the Code for design of soil and foundation of building in frozen soil region was corrected by the volume moisture content of unfrozen water.The error of corrected value was smaller than 6%.Thus,it is suggested that this corrected formula was used to determine the design frost depth of clay in seasonally frost ground regions.