吸力历史对非饱和弱膨胀土力学性质的影响

发布时间：2018-12-06 09:37

【摘要】：对经历较广吸力范围内不同吸力历史的非饱和弱膨胀土进行了一系列吸力控制的三轴剪切试验。关于最大吸力的施加,高吸力采用蒸汽平衡法;较低吸力采用轴平移技术。试验结果表明:在净应力和吸力相同条件下,经过湿化试样的应力-应变关系曲线升高、剪缩体变小;经过高吸力试样的应力-应变关系曲线也升高、剪缩体变小,随着经历过最大吸力的增加其应力比-应变关系、体变表现出的超固结土特性明显。其主要原因是前期试样受过较大的吸力,相当于受过较大前期固结压力,同时弱膨胀土失水收缩性明显,经过较大吸力后试样孔隙比明显减小,使试样剪切过程中表现出超固结黏土的特性。因此,讨论非饱和弱膨胀性土的应力-应变关系和强度时需考虑吸力历史引起的体积收缩影响。
[Abstract]:A series of triaxial shear tests of unsaturated weakly expansive soils with different suction histories have been carried out under the control of suction. For the maximum suction, the high suction is steam equilibrium, and the lower suction is the axial translation technique. The experimental results show that under the same net stress and suction, the stress-strain curve of the wetted specimen increases and the shearing shrinkage becomes smaller. The stress-strain curve of the high suction specimen also increases and the shear shrinkage becomes smaller. With the increase of the maximum suction, the stress-to-strain relationship of the superconsolidated soil is obvious. The main reason is that the sample has been subjected to a large suction, which is equivalent to the consolidation pressure, and the shrinkage of the weak expansive soil is obvious, and the porosity ratio of the sample decreases obviously after the larger suction. The properties of overconsolidated clay are shown in the shear process of the specimen. Therefore, the stress-strain relationship and strength of unsaturated weakly expansive soils should be discussed by considering the volume shrinkage caused by suction history.
【作者单位】：华北水利水电大学河南省岩土力学与结构工程重点实验室;上海大学土木工程系;
【基金】：国家自然科学基金项目(No.11272194) 河南省基础与前沿研究计划项目(No.132300410021) 华北水利水电大学高层次人才基金项目(No.40437)~~
【分类号】：TU443

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