Experimental And Simulation Study On The Characteristics Of Frost Heave In Saturated Soil

Seasonal frozen soil freezes and thaws under cyclic freezing and thawing conditions,and the harm caused cannot be ignored.In order to solve the practical problems in the economic development in frozen soil areas better,and meet the needs and development of human survival.We should study the impact of different factors on the process of soil frost heaving and master its influence law.It is of great significance to prevent and remediate the damage of frost heave and thaw caused by frozen soil.In this paper,the experiments and simulations are used to study the relevant characteristics of the soil frost heave process,and the influence of different factors on soil frost heave was analyzed.Experimented different particle sizes and different temperature conditions by building an indoor soil frost heaving experiment platform,.During the experiment,the amount of frost heave increased firstly and then decreased with the cold temperature decreases.And it increased with the increase of soil particles.The change law of the rate of frost heave is consistent with the amount of frost heave.The time required for the stable temperature distribution inside the sample increased with the decreases of the cold temperature and decreased with the increase of soil particles.The melting amount and thawing rate in the thawing process are consistent with the freezing process.The duration of the ice thawing process in the thawing process increased as the freezing temperature decreases and the particle size increases.Generated different types of soil structure models based on the self-built stacking method of the research group.The Boltzmann-MRT equation and the enthalpy-based phase transition model were used to simulate the permeability characteristics of the soil structure.The relative errors between the simulated and theoretical values of permeability and tortuosity were 20% and 5%,respectively.It verified the reliability of the soil structure generation method and the simulation method used for permeability characteristics.The average maximum geometric supercooling degree in the freezing process of the sample increased firstly and then decreased with the increase of the distribution range of the soil particle radius.However,it increased with the increase of the soil particle radius.Due to the existence of geometric supercooling,the pore water in the large pore size structure was frozen into ice completely during the freezing process,and the pore water in the small is in a state of supercooled water or ice water equilibrium.On the basis of the experiments,using COMSOL Multiphysics software to establish a calculation model for the simulation study of the frost heaving characteristics in saturated soil.Combined with the generated soil structure models and their permeability characteristics,explored the influence law of frost heave characteristics.This article explores the influence of the hot temperature,cold temperature,temperature gradient,particle distribution range and particle size on the frost heave volume,temperature distribution,ice relative volume and frost heave characteristics.It was verified that even under the same temperature gradient,the temperature of the cold or hot temperature will affect the frost heave characteristics of the soil.The amount of frost heave and the rate of frost heave decreased with the increases of the hot temperature.They increased with the decreases of the cold temperature and increased with the increase of the soil particles radius.During the freezing process,there are three areas in the sample: completely frozen area,incompletely frozen area and unfrozen area.The completely frozen area increased with the decrease of the hot temperature and increased with the decreases of the cold.The change in the unfrozen area was opposite to the completely frozen area.