黄河冲积粉土的吸力和强度特性关系  

Relationship Between Matric Suction and Strength Characteristic of Yellow River Alluvial Silts

作　　者：彭丽云[1] 李涛[1] 刘建坤[1] 

机构地区：[1]北京交通大学土木建筑工程学院,北京100044

出　　处：《北京交通大学学报》2009年第4期129-133,共5页JOURNAL OF BEIJING JIAOTONG UNIVERSITY

基　　金：国家自然科学基金资助项目(50579002;50678020)

摘　　要：采用GDS非饱和三轴仪对黄河冲积粉土击实土样进行同时控制净室压力和吸力的三轴剪切试验,研究了吸力和土样强度之间的关系.试验结果表明,非饱和与饱和土样均呈现出应变硬化的双曲线形应力-应变关系;非饱和状态下土样的内摩擦角近似等于饱水状态下的有效内摩擦角,同时总黏聚力随吸力增加而线性增大;随着吸力的增大,土样的强度提高,说明吸力对土体具有强化作用;土样临界状态线的斜率是一个与吸力无关的常数,临界状态线在q轴上的截距μ反映了吸力对强度的贡献,对该击实粉土,μ和s呈线性关系.The triaxial tests on compacted Yellow River alluvial silts are carried out under the controlled cell pressure and matric suction to study the relations between suction and strength behavior by using a GDS triaxial apparatus. It is found that the stress-strain curves with strain hardening behavior of both saturated and unsaturated alluvial silts can be simulated by a hyperbola, and the total cohesion increased with suction. Meanwhile, the effective friction angle under unsaturated state is close to that under saturate state. It is also observed that the strength envelopes on q-p plane with different matric suction exhibited linear relationship. The slope of the critical state line is independent of the matric suction. Linear relationship is also shown between the parameter μ and s with matric suction range from 0 to 200 kPa. The parameter μ is an intercept of the critical state line at q axis, which is the contribution of matric suction to shear strength.

关 键 词：粉土 非饱和土 三轴试验 基质吸力 抗剪强度 

分 类 号：O319.56[理学—一般力学与力学基础]