摘要
黄土既有非饱和性,又有结构性。首先在控制基质吸力的条件下进行了原状黄土与重塑黄土的非饱和直接剪切试验,分析了两种结构性状非饱和土的基质吸力对净应力强度指标、Fredlund抗剪强度公式中参数b、以及Bishop抗剪强度公式中参数的影响。表明两种土的黏聚力随基质吸力的增大而增大,b和均随基质吸力的增大而减小;在相同基质吸力条件下,原状黄土的黏聚力、b和均大于重塑黄土。其次,通过无侧限抗压试验,测试了不同含水率原状黄土、重塑黄土和饱和黄土的单轴抗压强度,得到了不同含水率下原状黄土和重塑黄土的构度值。最后,探讨了非饱和黄土的构度与基质吸力、净应力强度指标、参数b和之间的关系。得到非饱和黄土的b和值随构度分别有单调的变化规律;相同构度值条件下,原状黄土的b和值均大于重塑黄土的值,反映了两种非饱和土结构性状的差异。
The loess is structural and unsaturated.Direct shear tests on intact loess and remold loess are firstly carried out by controlling the matric suction of unsaturated soil.Then the effect of the matric suction on the net stress strength index,parameter bin the Fredlund shear strength formula and parameter in the Bishop effective stress formula of unsaturated soil is analyzed respectively.The experimental results show that net stress strength index increases with the increasing matric suction,band decreases with the increasing matric suction,and under the same matric suction,the net stress strength index,band of the intact loess are all larger than those of the remold loess.Besides,the unconfined compressive strengths of the intact loess,remold loess and saturated loess are measured by means of the single axial compression instrument.According to the definition of structural indices,the structural index of intact loess and remold loess with different water contents are obtained based on the unconfined compressive strength.Finally,the relationship among the net stress strength index and parameters b,and structural index is also explored.The values of band unsaturated loess have the monotonic variation with the structural index.Under the same configuration conditions,the values of band of the intact loess are greater than those of the remolded loess,which reflects the differences in structural traits of the two types of unsaturated soil.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2013年第S1期68-75,共8页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(10872161
41272320)
教育部高等学校博士学科点专项科研基金项目(20106118110011)
关键词
黄土
强度
基质吸力
非饱和特征参数
loess
strength
matric suction
characteristic parameter of unsaturated soil
