昆明地区分布着广泛且厚度稳定的泥炭土，具有有机质含量高、孔隙率大、含水量丰富等特点，在人工冻结作用下其冻胀特性非常显著。为此，本项目通过自制冻胀试验装置研究泥炭土在不同温度梯度、不同初始含水量及外荷载作用下，土体中温度场演化、水分迁移、土体冻胀特性的变化规律，构建人工冻结泥炭土水分场、温度场、应力场三场耦合作用的数学模型。同时对冻胀试验过程的土样进行CT扫描试验，采用数字图像处理技术从CT切片图像中提取出固体土颗粒、未冻水及分凝冰的细观结构动态变化特征，建立描述冰透镜体形成及生长过程的土体冻胀模型。考虑土颗粒骨架与孔隙空间结构信息的影响，开发格子Boltzmann-有限元耦合算法，模拟水热力耦合作用下泥炭土冻结过程中液态水结晶、水分迁移、冰透镜体形成及生长过程。本研究将基于冰透镜体的生长机制揭示泥炭土的冻胀特性，并为泥炭土层人工冻结法的设计及施工提供关键科学依据。

There is a wide range of peaty soil with stable thickness in Kunming，whose organic matter content is high, porosity is large and the water content is extremely rich. In the artificial freezing process, the peaty soil has significant frost heaving behaviors. Therefore, this project is to study heat transfer, moisture migration and frost heaving characteristics in the condition of different temperature gradients, initial water content and loads with the self-made frost heave test device and the mathematical model will be established coupling moisture, heat and stress field. Moreover, the CT scanning test will be done for the soil sample in the process of frost heave test. Based on the digital image processing technology, the dynamic micro structure characteristics of soil particles, water, and ice will be extracted from the CT slice images. The soil frost heave model will be set up according to the ice lens’ formation and growth process. Considering the influence of soil particles skeleton and pore space structure information, the algorithm coupling lattice Boltzmann method and finite element method is developed to simulate water crystallization, moisture migration, ice lens formation and growth. This project will reveal the frost heaving characteristics of peaty soil based on ice lens growth, and provide scientific basis for the design and construction of artificial freezing method in peaty soil.