Study On Elastic Modulus Of Ice-containing Unsaturated Soil Based On REV Model

The economic value and strategic potential of China’s economy and engineering technology.In order to make better use of the resources of the frozen soil area,a large number of frozen soil projects such as transportation,water conservancy and electric power,civil industrial buildings have been carried out successively.At the same time,the promotion of the western development has made many large-scale projects implemented in the cold area.In the development of construction projects in cold area,it will inevitably touch a series of problems about frozen soil,so in order to further develop the economic construction in cold area,the study of frozen soil area is particularly important.Among them,the elastic modulus of frozen soil,as one of the criteria to judge the stability of engineering soil,plays an important role in engineering application.Therefore,it is urgent to study the elastic modulus of frozen soil.In cold areas,media such as water in the soil pore space are frozen,thus that their elastic modulus significantly significantly.Based on this method,a new method for selecting REV(Representative Elementary Volume)uses porosity as a representative parameter of the model.Under the condition of considering freezing,this paper adopts the "point-line-surface" model based on REV,which is the rough "point" structure volume weighted REV model for frozen soil-related information,the combined "line" structure volume weighted REV model for frozen soil-related data,and the concrete "surface" structure volume weighted REV model for all the basic parameters of frozen soil,and the calculation formula of the elastic modulus under each model is derived.The actual frozen clay is used as an example to verify the model,the elastic modulus calculated by establishing the model is consistent with the actual situation.The maximum and minimum error of the volume-weighted REV model of the concrete "surface" structure and the measured data are-17.871% and-0.096% respectively.Then and analyze the elastic modulus of each model and the influence mechanism of various factors,it is found that the influence of elastic modulus and various parameter factors deduced from the established model,the results show that the elastic modulus increases with the initial water content,porosity,pore channel distribution coefficient and curvature increase.In this paper,we established a macroscopic cross-scale soil column model,calculated the water-heat-force coupling with COMSOL,studied the changes of the temperature field,the saturation of unfrozen water,the saturation of ice and the stress and strain,and obtained the change trend and distribution of the parameters.It is found that the temperature of the soil column model gradually decreased during the freezing process,and the change of the temperature field directly affected the content and distribution of pore ice and unfrozen water,and further affected the change trend of unfrozen water saturation and ice saturation.The decrease of unfrozen water saturation and the increase of ice saturation make the soil column swell,which results in the corresponding change of stress and strain.The simulation results are analyzed and compared with the volume weighted REV model of the concrete "face" structure.The elastic modulus obtained from the simulation is close to the calculated value of the volume weighted REV model of the concrete "face" structure,which further verifies the correctness of the model.