[This article belongs to Volume - 53, Issue - 04]
Gongcheng Kexue Yu Jishu/Advanced Engineering Science
Journal ID : AES-16-10-2021-67

Title : Effect and Modeling of Wetting-Loading-Heating on Water Retention Capacity of Silty Clay
CHEN Yong, YAN Kexiang, SU Jian, WANG Shimei, TAN Jianmin,

Abstract :

The water holding capacity of unsaturated soils is usually reflected by the changing laws of soil-water characteristic curves. The important influence of factors such as load and temperature on the soil-water characteristic curve has been gradually recognized, but studies on the combined effect of moisture-load-heat on the soil-water characteristic curve are rarely reported, and the analysis of its dominant influence factors is even rarer. In order to explore the water holding capacity of silty clay under the combined action of moisture-load-heat, this paper carried out dry-wet cycle experiments of silty clay under different vertical stress and temperature conditions, and analyzed the influence mechanism, characteristics and characteristics of each factor. Importance, and established a predictive model reflecting the interaction of multiple factors. The research results show that With the increase of the vertical stress, the air intake value of unsaturated soil increases, the dehumidification rate decreases, and the hysteresis effect of the dry-wet cycle process becomes stronger, and it shows the same characteristics at all temperatures. Comparing the experimental curves under the same vertical stress and different temperatures, it is found that the air intake value of the soil is relatively slightly lower when the temperature is higher. The vertical stress has the greatest influence on the water holding capacity of the soil, but it is mainly limited to the low suction stage the dry-wet cycle has the second effect, and it will rapidly decay as the number of cycles increases the temperature has a small influence and is When the suction value or density is high, it can be ignored. The improved L model based on the Logistic curve is more suitable for the soil-water characteristic curve fitting of Badong silty clay than the commonly used V-G model. The comprehensive research results show that the root cause of the change of the characteristic value caused by the vertical stress is the change of the internal pore structure, which leads to the difference in water holding performance; temperature mainly affects the water holding performance of the soil in a low-stress and low-suction state 3 types The degree of influence of occurrence conditions on water holding capacity of silty clay is vertical stress>dry-wet cycle>temperature distribution the improved L model can effectively reflect the evolution of water holding capacity of silty clay under the combined action of moisture-load-heat feature.