高速铁路地基膨胀泥岩吸力特性及计算模型研究  

Study on Suction Characteristics and Calculation Model of Expansive Mudstone of High Speed Railway Foundation

作　　者：马丽娜[1,2] 梁东方 王起才 姚裕春[3] MA Lina;LIANG Dongfang;WANG Qicai;YAO Yuchun(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;Department of Engineering,University of Cambridge,Cambridgeshire CB21PZ,UK;China Railway Eryuan Enginering Group Co.,Ltd.,Chengdu 610031,China)

机构地区：[1]兰州交通大学土木工程学院,甘肃兰州730070 [2]剑桥大学工程系,英国剑桥郡CB21PZ [3]中国中铁二院工程集团有限责任公司,四川成都610031

出　　处：《铁道学报》2022年第11期88-94,共7页Journal of the China Railway Society

基　　金：甘肃省教育科技创新项目(2021CYZC-28);长江学者和创新团队发展计划(IRT_15R29)。

摘　　要：处于近地表一定深度范围内泥岩为非饱和状态,加之泥岩自身特殊的膨胀性与易崩解性,引入吸力研究分析泥岩的工程特性是一种可行的探索。以某高速铁路地基中弱膨胀泥岩为研究对象,采用滤纸法分析含水率、干密度对泥岩吸力的影响。研究结果表明:泥岩的总吸力和基质吸力随着含水率的增加呈非线性减小。在低含水率状态下,水分以气态形式进行迁移,且泥岩的总吸力和基质吸力均随着干密度的增加而增加;高含水率状态下泥岩的总吸力受干密度影响较小。在半对数坐标中,土水特征曲线近似呈“S”型;随着干密度的增加,泥岩的进气值逐渐增大,残余基质吸力和残余饱和度保持相对稳定。对泥岩土水特征曲线计算模型探讨发现LangumuirEXT2数学模型与试验数据拟合良好。并采用Gardner模型、Van Genuchten模型和Fredlund&Xing模型对泥岩的土水特征曲线进行了拟合,发现Fredlund&Xing模型最适用于本泥岩的土水特征曲线;另建立了修正的三模型,其中Gardner修正模型和Van Genuchten修正模型与试验数据拟合较好,适用于该类土体的土水特征曲线建模。Mudstone that locates in a certain depth near the surface is unsaturated.Considering the special expansibility and disintegration properties of mudstone itself,the introduction of suction which is used for analyzing the engineering characteristics of mudstone is a feasible exploration.Based on the weak expansive mudstone of a high-speed railway foundation,in this paper,the filter paper method was used to analyze the effect of water content and dry density on mudstone suction.The results show that the total suction and matrix suction of the mudstone decrease nonlinearly with the increase of water content.The water migrates in the gaseous form under the condition of low water content.The total suction and matrix suction increase with the increase of dry density.The total suction of mudstone under high water content is less affected by dry density.The soil-water characteristic curve is approximately"S"-shaped in semi-logarithmic coordinates.With the increase of dry density,the intake value of mudstone gradually increases while the residual matrix suction and residual saturation remain relatively stable.The LangumuirEXT2 mathematical model fits well with the test data.The Gardner model,Van Genuchten model and Fredlund&Xing model were used to fit the soil-water characteristic curve of mudstone.It is found that the Fredlund&Xing model is most suitable for the soil-water characteristic curve of the mudstone.Finally,the modified three models were established,of which,the modified Gardner model and the modified Van Genuchten model,which fit well with the experimental data,are suitable for modeling the soil-water characteristic curve of this type of soil.

关 键 词：高速铁路 泥岩 基质吸力 土水特征曲线 模型 

分 类 号：TU443[建筑科学—岩土工程]