Investigation of the Temperature and Horizontal Freezing Force of Loess in Three-Dimensional Freezing

Abstract

Seasonal frozen soil has significant impacts on changes in soil mechanical properties, settlement, and damage to foundations. In order to study variations in the temperature and horizontal freezing force of loess during three-dimensional freezing, a three-dimensional freezing model test of loess was carried out. This experiment analyzed and studied the soil temperature change distribution characteristics, horizontal freezing force distribution rules, and water migration phenomena caused by temperature. The research results show that the temperature change in soil samples exhibits a “ring-like” decrease from the outside to the inside. When the soil temperature reaches the supercooling point, the cooling curve jumps and rises, and this is accompanied by a stable section with constant temperature. In the late freezing period, the temperature rate drops slowly. Under the action of freezing, the horizontal freezing forces at different positions have similar change characteristics and can be divided into four change stages: stable stage, rapid freezing stage, “secondary” freezing stage, and freezing–shrinkage–rebound stable stage. At lower moisture contents, loess samples undergo freeze–thaw shrinkage during the freezing process. During the rapid freezing stage of soil samples, the water in the soil sample migrates and causes secondary freezing. After the rapid freezing stage, the soil temperature continues to decrease, and the horizontal freezing force no longer decreases.