非饱和压实黄土应力应变特性试验  

Experiment on stress-strain characteristics of unsaturated compacted loess

作　　者：张沛然[1] 黄雪峰[1,2] 扈胜霞[3] 杨校辉[1] ZHANG Pei-ran;HUANG Xue-feng;HU Sheng-xia;YANG Xiao-hui(College of Civil Engineering,Lanzhou Univ.of Tech.,Lanzhou 730050,China;Department of Architectural Engineering,Logistical Engineering University,Chongqing 401311,China;Architectural and Civil Engineering Institute,Yan’an University,Yan’an 716000,China)

机构地区：[1]兰州理工大学土木工程学院,甘肃兰州730050 [2]解放军后勤工程学院土木工程系,重庆401311 [3]延安大学建筑工程学院,陕西延安716000

出　　处：《兰州理工大学学报》2018年第5期126-131,共6页Journal of Lanzhou University of Technology

基　　金：国家自然科学基金(51309199);陕西省科技统筹创新工程计划课题(2012KTDZD03-04)

摘　　要：为探究压实度和吸力对填方黄土应变应力关系及模型(参数)的影响特征,开展了控制压实度(干密度)和吸力的三轴固结剪切试验.结果表明:非饱和黄土的应力应变关系因压实度和吸力的变化经历了应变硬化型、理想弹塑型及应变软化型3种基本形态,其中低压实度(75%)时土样表现出鲜明的应变硬化特征;土样的应力比水平、体变形式(剪胀、剪缩)及体变量均与压实度和吸力条件相关联,在低压实度及低吸力状态下土样以剪缩为主,反之不同;在双曲线线性化拟合相关参数求取中,结合体变-应力比曲线所反映的土样力学特性,其中土样的初始切线模量在低压实度(75%)时受土样吸力大小的影响较弱.黄土填料受压后的结构排列程度与其吸力大小共同决定着压实黄土的力学特性,提高填方黄土物料的压实水平对填方地基的强度及变形控制具有重要意义.In order to explore the characteristics of the effect of the compactness and suction on the dependence of stress on strain and model(parameters)of filling loess,three-axis consolidation and shear tests were carried out to control the compactness(dry density)and suction.The result shows that the stress vs strain relation of unsaturated loess will experience three basic forms of strain hardening,ideal elastoplasticity,and strain softening due to the change of compactness and suction.Among them the strain hardening feature will be distinctly shown by soil sample with low compactness(75%).The stress ratio level,form of bulk deformation(shear expansion,shear shrinkage),and its amount of the soil sample will be correlated to the compactness and suction,the soil sample will be mainly of shear shrinkage under condition of low compactness and low suction.On the contrary,the thing will be different when the relevant parameters are to be found for linearized fitting of hyperbola,the mechanical properties of the soil sample reflected by bulk deformation vs stress ratio curve are taken into account.Among them the influence of soil sample suction on initial tangent modulus of soil sample will be weaker at low compactness(75%).The structural arrangement degree and suction magnitude of compacted loess will in common determine the mechanical characteristics of the loess fillings.Improvement of the compaction level of filled loess material will be of great importance to control the strength and deformation of the filled foundation.

关 键 词：压实土 压实度 吸力 强度 应变 

分 类 号：TU411[建筑科学—岩土工程]