合肥地区重塑黏性土细观结构演化三轴CT试验  

Triaxial CT Tests of Meso-Structure Evolution of Remodeled Cohesive Soil in Hefei

作　　者：朱宝龙[1] 巫锡勇 李晓宁[1,2] 魏久平[1] 

机构地区：[1]西南科技大学土木工程与建筑学院,四川绵阳621010 [2]西南交通大学地质工程系,四川成都610031

出　　处：《西南交通大学学报》2015年第1期144-149,共6页Journal of Southwest Jiaotong University

基　　金：国家自然科学基金资助项目(41172261);四川省科技支撑计划资助项目(2011SZ0178)

摘　　要：为研究非饱和黏性土的细观结构演化特征,采用CT-多功能土工三轴仪,对合肥地区重塑黏性土在不同吸力、不同净围压下进行了非饱和固结排水三轴试验,得到了土体内部结构演化的CT图像、CT数平均值和方差.研究结果表明：净围压对土体细观结构演化影响显著.净围压较低时,土体经短暂压密后,原有孔洞消失,产生裂纹,裂纹宽度和长度随时间扩展较快——吸力越大,裂纹扩展、贯通程度越显著;CT数平均值减小0.26%-4.16%,方差增大15.82%-37.80%,说明土体密度变得不均匀.净围压较高时,土体整体被压密,一般无裂纹产生;CT数平均值增大1.22%-14.87%,方差减小10.02%-83.37%,说明土体密度变得更均匀,土体更致密.In order to investigate the meso-structure characteristic of unsaturated cohesive soil, unsaturated consolidated-drained triaxial shear tests for remodeled cohesive soil in Heifei were carried out under different suctions and net confining pressures with CT （ computed tomography） multi-function tfiaxial apparatus, and the CT images and corresponding CT data （CT data average an its inner structure evolution were obtained. The research result shows that net confining d variance） of pressure has a great effect on the meso-structure evolution of soil. When the net confining pressure is low, original holes in soil disappear, unsaturated cohesive soil will generate cracks rapidly after transient compaction, and the width and length of cracks extend with time. The larger the suction is, the more significant the crack propagation is. The CT data average decreases by 0.26% to 4.16% compared with the original value, while the CT data variance increases by 15.82% to 37.80% compared with the original variance to indicate that soil density becomes nonuniform. When the net confining pressure is high, soil as a whole is compacted and almost does not generate cracks. Compared with the original values, the CT data average increases by 1.22% to 14.87% , and the variance decreases by 10.02% to 83.37% to indicate that soil density becomes uniform and the soil body is more compact.

关 键 词：合肥重塑黏性土 CT 细观结构 CT数 

分 类 号：TU411.91[建筑科学—岩土工程]