北方季节性冻土区地基土冻胀分析

Analysis of Frost Heave of Foundation Soil in Northern Seasonal Frozen Soil Area

季节性冻土地区地基土的冻胀破坏是引起建筑物基础产生变形的重要原因。为了深入研究季节性冻土地区影响地基土的冻胀因素,结合长春市具体工程实例,通过有限元模拟软件,实现了热-力-水3个物理场的耦合。基于已有的冻胀理论,考察了负温、初始含水量、土体性质对地基土的影响机理,同时分析了法向冻胀力与各个参数之间的变化关系。研究表明:法向冻胀力与负温、初始含水量近似呈线性增长关系,冻土初始含水量对地基土冻胀作用影响最大;黏土的法向冻胀力最大,粉质黏土次之,粗砂土最小;最大法向冻胀力主要集中在土体深度为0 m~0.6 m范围内,超出此范围,随着土体深度增大,法向冻胀力急剧减小。

The frost heave damage of foundation soil in seasonal permafrost region is an important reason for the deformation of building foundation.In order to deeply study the frost heave factors affecting foundation soil in seasonal permafrost regions,combining with a concrete project in Changchun City,the coupling of thermal and water physical fields was realized through finite element simulation software.Based on the existing frost heave theory,the influence mechanism of soil properties with negative temperature and initial water content on foundation soil is investigated,and the relationship between normal frost heave force and various parameters is analyzed.The results show that the relationship between normal frost heave force and the initial water content at negative temperature increases linearly,and the initial water content of frozen soil has the greatest influence on the frost heave of foundation soil.The normal frost heave force of clay is the largest,followed by silty clay and coarse sand.The maximum normal frost heave force mainly concentrates in the soil depth range of 0~0.6m,and beyond this range,the normal frost heave force decreases sharply with the increase of soil depth.