ANALYSIS OF THE FROST HEAVING CHARACTERISTICS OF CARBONATE-SALINE SOIL IN WESTERN JILIN PROVINCE, CHINA

摘要

A large area of carbonate-saline soil is distributed in western Jilin Province. To effectively prevent and treat the frost heaving damage of engineering structures, this paper studied the frost heaving characteristics of carbonate-saline soil in western Jilin Province, where such phenomena as frost heaving of roadbeds as well as cracking and damaging of headrace channels have become increasingly severe. With carbonate-saline soil obtained from different sampling points and depths in the Daan and Sanzhi-gou areas of Jilin Province as the research object, the influences of temperature, moisture content, compaction degree and salt content on the frost heaving characteristics of soil samples were studied and analysed through laboratory frost heaving tests. The results showed that the frost heaving ratio of the soil samples, which had little differences in similar properties, increased with an increase in moisture content, salt content and compaction degree generally, and soil samples with a higher salt content had the best frost heaving compaction degree. Influences of temperature on the frost heaving ratio were related to the salt content, where the freezing point of a soil sample with a high salt content was lower and the unfrozen-moisture content was higher. Moreover, there was no obvious temperature interval with constantly changing frost heaving deformation. The frost action lasted longer, ice crystals and salt crystals developed sufficiently and the ultimate frost heaving ratio reached a higher value. Soil samples from the Daan area have the characteristics of high clay content, large specific area, strong water holding capacity, low freezing point and long duration of frost action, and the ultimate frost heaving ratio of these soil samples was higher than those of the San-zhigou area. Considering the synthetic effects from internal and external causes, a comprehensive study is carried out for the frost heaving properties of carbonate-saline soil in different areas combined with soil properties and external factors.