Abstract
The soil-water characteristic curve of silty soil in seasonal frozen area during freezing-thawing process was studied in this study. By means of a laboratory test, specimens with different compaction degrees and different initial moisture content were prepared and put into the temperature change testing machine for freeze-thaw action. The influence of different degrees of compaction and different times of freeze-thaw action on SWCC of low liquid limit silt was analyzed, a V-G model was used to fit the test data, and a set of fitting parameters with a reference value was obtained. At the same time, the change of microstructure between soil particles during the freezing-thawing cycle is illustrated. The results showed that with the same water content and the same compactness, the matric suction of the test soil decreased with the increase of freeze-thaw cycles. For the same number of freeze-thaw cycles, the greater the compactness, the greater the matric suction of the soil. The V-G model can well represent the SWCC of low liquid limit silt during the freeze-thaw cycle.
Highlights
China’s seasonal frozen soil area takes up 53.5% of its land area and is widely distributed throughout North China, Northwest China, and Northeast China [1]. e building foundation, road subgrade, and hydraulic structure’s properties of seasonal frozen soil areas are affected by the freezing-thawing process [2]
Materials. e soil samples used in the tests were taken from Daxing airport in Beijing. e average minimum temperature in this region is −16°C for many years, and the average maximum temperature with a hottest temperature of 7 days is 34°C, which is typical of regions with seasonal frozen soil. e performance-related soil property tests, including the sieve analysis, Atterberg limits, and the Proctor test were performed on the selected materials. e sieve analysis and the Atterberg limit tests were carried, out and the result displayed that the soil is defined as the low liquid silt according to Universal Soil Classification System (USCS)
With the same water content, the matric suction of the test soil decreases with the increase of the number of freezingthawing cycles, and the variation range of matric suction decreases with the increase of the number of freezingthawing cycles and tends to be stable
Summary
China’s seasonal frozen soil area takes up 53.5% of its land area and is widely distributed throughout North China, Northwest China, and Northeast China [1]. e building foundation, road subgrade, and hydraulic structure’s properties of seasonal frozen soil areas are affected by the freezing-thawing process [2]. Is kind of repeated freezing-thawing action in the superstructure of the damage is inevitable and lasts a long time. Ishikawa and Kawabata studied the effect of freezing-thawing action and water content on the mechanical properties of subgrade through the CBR test and model test of subgrade soil, and the results showed that the bearing capacity of subgrade increased in the freezing season and decreased in the melting season [4]. Lin et al [7] used a dynamic triaxial test to explore the law of accumulated plastic strain of soil samples under freezing and thawing. Compared with the complex stress state experienced by engineering soils, the freeze-thaw action often lasts for a long time and causes great damage to the superstructure. The freeze-thaw action in engineering often occurs underground and has concealment. erefore, it is necessary to discuss and analyze the effect and law of the effect of freezing and thawing on soil water-holding capacity
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