河西盐渍土的低温冻土三轴试验与模型研究  

Low-temperature Frozen Soil Triaxial Test and Model Study on Saline Soil in Hexi Area

作　　者：罗崇亮 余云燕[1] 岳建平[1,2] 朱明哲 刘武通 LUO Chong-liang;YU Yun-yan;YUE Jian-ping;ZHU Ming-zhe;LIU Wu-tong(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou Gansu 730070,China;School of Civil Engineering,Hexi University,Zhangye Gansu 734000,China)

机构地区：[1]兰州交通大学土木工程学院,甘肃兰州730070 [2]河西学院土木工程学院,甘肃张掖734000

出　　处：《公路交通科技》2021年第6期61-69,共9页Journal of Highway and Transportation Research and Development

基　　金：国家自然科学基金项目(51268031,11662007);甘肃省基础研究创新群体项目(145RJIA332)。

摘　　要：盐渍土在冻结过程中,结构孔隙中的盐溶液逐渐转变为盐溶冰,盐渍土结构由之前的"土骨架结构"变为"土-盐溶冰骨架结构"导致力学行为发生了较大变化。以张掖地区某道路工程盐渍土路基填料为研究对象,通过低温冻土三轴剪切试验,分析了不同冻结时长、不同冻结温度下盐渍土的变形特性及本构模型。研究了冻结盐渍土的Duncan-Chang模型参数,基于Duncan-Chang模型利用SPSS回归分析建立了冻结盐渍土主应力差(σ1-σ3)及切线模量Et与温度T和围压σ3的多因素耦合模型。研究发现:(σ1-σ3)-ε1曲线呈3阶段发展,随着冻结时间的增加,冻结温度降低,主应力变差,黏聚力及内摩擦均增大;耦合模型参数a1和b1与温度T呈正相关,与围压σ3呈负相关,其主导变量均为围压σ3。最后将耦合模型计算结果与试验结果对比,发现耦合模型能够较好地预测计算冻结盐渍土的本构关系。During the freezing process of saline soil,the salt solution in the structural pores is gradually transformed into salt-dissolved ice,and the structure of saline soil changed from the previous"soil skeleton"to"soil-salt dissolved ice skeleton",which caused a great change in the mechanical behavior.Taking the saline soil subgrade filling of a road project in Zhangye area as the research object,the deformation characteristics and the constitutive model of saline soil under different freezing time and different freezing temperatures are analyzed by triaxial shear test on low-temperature frozen soil.The Duncan-Chang model parameters of frozen saline soil are studied,the multi-factor coupling model of frozen saline soil principal stress difference(σ1-σ3)and the multi-factor coupling model of Et,T andσ3 are established based on Duncan-Chang model using SPSS regression analysis.It is found that(1)The(σ1-σ3)-ε1 curve develops in 3 stages.As the freezing time increases,the freezing temperature decreases,the principal stress becomes worse,and the cohesion and internal friction increase.(2)The coupled model parameters a1 and b1 are positively correlated with the temperature T and negatively correlated with the confining pressureσ3,and their leading variables are confining pressureσ3.Finally,comparing the calculation result of the coupling model with the test result,it is found that the coupling model can better predict and calculate the constitutive relationship of frozen saline soil.

关 键 词：道路工程 Duncan-Chang模型参数 冻土三轴试验 盐渍土 SPSS回归分析 耦合模型 

分 类 号：TU411[建筑科学—岩土工程]