非饱和土真三轴双剪新强度准则及验证  

A New Twin-shear True Triaxial Strength Criterion of Unsaturated Soils and Its Validations

作　　者：张常光[1] 范文[2] 赵均海[1] 杜文超[1] 

机构地区：[1]长安大学建筑工程学院,陕西西安710061 [2]长安大学地质工程与测绘学院,陕西西安710054

出　　处：《同济大学学报（自然科学版）》2015年第9期1326-1331,共6页Journal of Tongji University:Natural Science

基　　金：国家自然科学基金(41202191);中国博士后科学基金(2014M562358);陕西省自然科学基础研究计划(2014JQ7290;2015JM4146);长安大学中央高校基本科研业务费专项基金(2014G1281072)

摘　　要：依据非饱和土的双应力状态变量理论,在俞茂宏双剪新强度准则的基础上,建立了适用于非饱和土的真三轴双剪新强度准则,并用文献非饱和粉砂刚性与柔性真三轴试验结果进行了验证.研究结果表明:该分段线性的真三轴双剪新强度准则能反映非饱和土强度的中间主应力效应及其区间性与单轴拉压不等特性,且可线性逼近拓展的非线性Spatially Mobilized Plane准则;Mohr-Coulomb强度准则的预测值偏小、外接圆Drucker-Prager准则的预测值明显偏大,这两个准则对非饱和土的真三向应力状态及试验数据均不具有很好的适用性.On the basis of the new twin-shear strength criterion of Mao-Hong Yu and the two stress state variables theory, a new twin-shear true triaxial strength criterion is derived and validated by the rigid and flexible true triaxial tests of unsaturated silty sand available in the literature. It is shown that the new piecewise linear twin-shear true triaxial strength criterion proposed in this study can reflect strength characteristics of unsaturated soils, such as the effect and its range of intermediate principal stress and strength differences among uniaxial tension and uniaxial compression; the new twin-shear strength criterion can be a linear approximation of the extended nonlinear Spatially Mobilized Plane criterion;neither the Mohr-Coulomb strength criterion nor the circumscribed Drucker-Prager criterion has good applicability to true three dimensional stress states and test data of unsaturated soils, in that the predictions of Mohr-Coulomb strength criterion are small, whereas the predictions of circumscribed Drucker-Prager criterion are obviously large.

关 键 词：非饱和土 强度准则 真三轴试验 中间主应力 基质吸力 

分 类 号：TU432[建筑科学—岩土工程]