摘要
基于摩尔-库伦破坏准则,以室内动三轴试验为手段,研究了西宁、兰州、西吉、西安等地原状黄土的动强度特性,分析了振动次数及天然条件下各地区原状黄土初始孔隙比、天然含水率、塑性指数与动抗剪强度的区域性特征。研究表明:含水率相同条件下,随着固结应力的增大,黄土的动抗剪强度也逐渐增大,这种增加趋势成非正比关系;随着振动次数的累积作用,研究区自西北向东南部,黄土的粘聚力呈降低趋势,内摩擦角变化趋势较离散;天然状态下:黄土的初始孔隙比自西北向东南大致呈增大趋势,其动粘聚力也呈逐渐增强的趋势,内摩擦角呈减小的趋势;含水率自西北向东南大致呈增大趋势,随着含水率的增长黄土的动粘聚力逐渐增强,内摩擦角大致呈减小的趋势;随着原状黄土粘粒含量基本呈自西北向东南增大趋势,动粘聚力也逐渐增大,内摩擦角呈减小的趋势,但幅值减小不具有相似性。
Based on Mohr-Coulomb failure criterion,the dynamic strength characteristics of undisturbed loess in Xining,Lanzhou,Xiji and Xi'an are studied through dynamic triaxial test. The regional characteristics ofstandard of consistency state of other soil types. This can explain the special traits ofclassification of consistency state.Key words: Guizhou red clay; water content ratio; liquid index; equivalent range of liquid void ratio,natural moisture content,plasticity index and dynamic shear strength with different vibration frequencies and natural conditions are analyzed. The research results show that the dynamic shear strength of loess increases when consolidation stress rises under the same water content condition. However,the increase trend is not direct proportional. From northwest to southeast the cohesive force of loess decreases and the change in internal friction angle trends to disperse with the cumulative effect of vibration frequency. Initial void ratio and water content of loess under natural state rise from northwest to southeast,and the dynamic cohesive force enhances. On the contrary,internal friction angle decreases with the change of characteristics.With the increasing trend of clay content of the disturbed loess from northwest to southeast,the dynamic cohesive force increases and the internal friction angle decreases in the different amplitudes. These conclusions enriche the evaluation theory of loess regional dynamic characteristics and it is a universal method to reduce the cost of different loess regional classifications.
出处
《水文地质工程地质》
CAS
CSCD
北大核心
2013年第5期69-73,86,共6页
Hydrogeology & Engineering Geology
基金
黄土地震工程重点实验室开放基金项目(KLEE-12-003)
中国地震局基本科研业务经费资助(2012IESLZ01,2012IESLZ07)
关键词
黄土
动抗剪强度
区域特征
percentile loess
dynamic strength
regional characteristics
