关键词: 液氮取样器; 饱和软黏土; 样品尺寸; 有限元温度场数值模拟;

Abstract: Study on soil structure is one of the frontier topics in soil mechanics research.The key factors restricting the study of microstructure of saturated soft clay are experimental analysis method and sampling method.The soft clay with the engineering characteristics of high water content are not easy to be sampled, and it is necessary to obtain the original sample by means of thin-walled earth borrower and artificial freezing technology using liquid nitrogen as a cold source.This paper takes the silt of the Dapeng Bay Blowing and Silting Land Project in Shenzhen City as an example.Based on the thermos-physical parameters of frozen soil(unfrozen water content, thermal conductivity and volumetric heat capacity, etc.),the finite element method is used to simulate temperature field in sampling process.The temperature field effect generated by the sampling process is effective for obtaining microstructure samples.Accoring to the mineral composition and basic physical properties of saturated soft clay, the size of the microstructure sample is preliminarily determined, and the specifications of the liquid nitrogen artificial freezing sampler are reasonably determined, which are conducive to reconstructing the microstructure of the samples.This study effectively combines numerical simulation, experimental methods and theoretical calculations to provide a scientific basis for microscopic analysis of soil.

Key words: liquid nitrogen sampler; saturated soft clay; sample size; finite element method simulation of temperature field;