复杂水–力路径下非饱和砂质黄土增湿变形特性  

Wetting deformation characteristics of unsaturated sandy loess under complex hydro-mechanical paths

作　　者：蔡国庆[1,2] 韩博文 韦靖威 李舰[2] 赵成刚[2] CAI Guoqing;HAN Bowen;WEI Jingwei;LI Jian;ZHAO Chenggang(Key Laboratory of Urban Underground Engineering of Ministry of Education,Beijing Jiaotong University,Beijing 100044,China;School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China)

机构地区：[1]北京交通大学城市地下工程教育部重点实验室,北京100044 [2]北京交通大学土木建筑工程学院,北京100044

出　　处：《岩石力学与工程学报》2022年第S01期3073-3080,共8页Chinese Journal of Rock Mechanics and Engineering

基　　金：中央高校基本科研业务费项目(2021CZ109);国家自然科学基金资助项目(U2034204,52078031)

摘　　要：为研究复杂水–力路径下非饱和砂质黄土的增湿变形特性,采用GDS非饱和三轴仪,对非饱和砂质黄土开展偏应力作用下固结–加载–增湿–加载、固结–卸载–增湿–卸载2种复杂水–力路径的单线法三轴增湿试验,全面分析水–力路径和应力比对非饱和砂质黄土增湿变形特性的影响。试验结果表明:(1)轴向应变与增湿剪应变均随应力比的增加而减小;(2)应力比为0.25时,试样未达到饱和便发生剪胀破坏;经历加载路径试样比经历卸载路径试样的增湿剪应变、孔隙比发展更快,率先达到破坏;(3)应力比为0.5和0.75时增湿变形特性基本一致,湿化体应变、增湿剪应变均随湿化参数的增加先增加后趋于稳定,孔隙比随着湿化参数的增加先减小后趋于稳定,经历加载路径试样的最大湿化体应变、增湿剪应变与增湿前初始孔隙比均大于经历卸载路径的试样。In order to study the wetting-induced deformation characteristics of unsaturated sandy loess under complex hydro-mechanical paths,the single-line triaxial wetting tests of the two complex hydro-mechanical paths of consolidation-loading-wetting-loading and consolidation-unloading-wetting-unloading under deviator stress are carried out by GDS unsaturated triaxial apparatus for unsaturated sandy loess.The effects of hydro-mechanical path and stress ratio on the wetting-induced deformation characteristics of unsaturated sandy loess are comprehensively analyzed.The research results indicate that:(1)Both the axial strain and the wetting shear strain decrease with the increase of stress ratio.(2)When the stress ratio is 0.25,the specimen fails to reach saturation,and then the dilatancy failure occurs.The wetting shear strain and void ratio of the specimens that experienced the loading path develops faster than that experienced the unloading path,and are the first to reach failure.(3)When the stress ratio is 0.5 and 0.75,the wetting deformation characteristics are basically the same.The wetting volumetric strain and moistening shear strain both increase first and then become stable with the increase of the wetting parameters.The void ratio first decreases and then becomes stable with the increase of the wetting parameters.The maximum wetting volumetric strain,wetting shear strain and the initial void ratio before the moistening of the samples that experienced the loading path are all greater than that experienced the unloading path.

关 键 词：土力学 非饱和砂质黄土 增湿变形 单线法 复杂水–力路径 应力比 

分 类 号：TU444[建筑科学—岩土工程]