重塑膨胀土结构性损伤CT-三轴试验研究  

Study on the Mechanical Characteristics of Structural Damages of a Remolded Expansive Soil by CT-Triaxial Apparatus

作　　者：李贤[1] 彭贞[1] 汪时机[1,2] 陈正汉[3] 

机构地区：[1]西南大学工程技术学院,重庆400716 [2]Department of Civil and Environmental Engineering,Imperial College London [3]中国人民解放军后勤工程学院建筑工程系,重庆400041

出　　处：《西南大学学报（自然科学版）》2013年第6期131-135,共5页Journal of Southwest University(Natural Science Edition)

基　　金：国家自然科学基金项目资助(10902091);中央高校基本科研业务费专项资金资助(XDJK2010C014;XDJK2013C042);西南大学科研基金资助项目(SWU208010)

摘　　要：膨胀土是一种在世界范围内分布广泛的非饱和特殊土,具有吸水膨胀、失水收缩和反复胀缩的特性,被工程界称为灾害土.以南水北调中线工程南阳陶岔引水渠坡重塑膨胀土为研究对象,针对膨胀土裂隙性的结构特征,通过CT-三轴排水剪切试验,研究具有不同初始损伤程度和不同损伤位置的膨胀土试样结构演化情况及其力学特性.研究发现:轴向应变与偏应变之间成线性正比例关系,相同吸力不同围压时,围压越大,体应变最大值越大;相同围压不同吸力时,吸力越大,体应变达到最大值所用时间越短.研究结论可以为分析膨胀土变形、强度和稳定性问题提供科学依据,对保障膨胀土地区工程建设的顺利进行有重要的意义.Expansive soils are widely distributed throughout the world. Expansive soils will swell when they are wetting and will shrink when they are drying. They are characterized by repeated deformation. The expansive soil is called as disaster soil in civil engineering. The remolded expansive soil samples used in this experiment were collected from the slope of the Taocha Water Diversion Canal in Nanyang in the middle route of South-to-North Water Diversion Project. CT-triaxial apparatus was employed to study the structural characteristics of expansive soil fissures and investigate the evolution of expansive soil samples with different initial damage degrees and different damage locations and their mechanical characteristics. The following conclusions were drawn from our research. Deformation increased with increasing net confi- ning pressure when the suction remained unchanged. However, deformation decreased when the damage location was close to the outside of the sample. When the net confining pressure was fixed and the suction pressure varied, the time taken in the test for the deformation to reach the maximum was reduced with in- creasing suction pressure. The area of the damage in the soil sample was gradually reduced when the confi- ning pressure was more than 400 kPa. The value of ME increased, while the SD value decreased along the procedure of test. Under the same suction and net confining pressure, the more severe damages the sam- ples had, the more obvious changes in the values of ME and SD were observed. It is believed that the results obtained in this study can serve as a theoretical basis for the analysis of the deformation, strength and stability of expansive soils. It is of significance to the constructions in regions of expansive soils.

关 键 词：膨胀土 CT-三轴试验 损伤 结构演化 

分 类 号：TU411[建筑科学—岩土工程]