摘要
为预测基质吸力对巴东组碎屑土夹层蠕变行为的影响,开展其非饱和蠕变经验模型的研究。基于碎屑土夹层的非饱和蠕变试验,尝试改进Singh-Mitchell蠕变模型、Mesri蠕变模型:首先选取幂函数分段描述应变-时间关系曲线的各阶段,拟合模型参数与基质吸力关系,建立包含基质吸力的改进Singh-Mitchell蠕变模型、Mesri蠕变模型;其次根据蠕变曲线特点,对应力-应变曲线、应变-时间曲线进行非线性拟合,构建包含基质吸力-应力-应变-时间的非饱和蠕变经验模型;最后对比了3种蠕变模型的预测精度。结果表明:改进的Mesri模型基本能预测碎屑土夹层的蠕变全过程,虽然当偏应力水平增高时,预测值与试验值存在偏差,但其精度基本能够满足工程应用要求;提出的非饱和蠕变模型预测效果一般,改进的Singh-Mitchell模型预测效果最差。
In order to predict the influence of matric suction on unsaturated creep behaviors of weak intercalated soils of Badong Formation,the empirical research on its unsaturated creep models was carried out.Based on the unsaturated creep experiments,power function was used to express the relationship between strain and time in stages in order to improve the Singh-Mitchell creep model and the Mesri creep model.Then the relations between model parameters and matrix suction were fitted to establish the improved Singh-Mitchell creep model and Mesri creep model involving matrix suction.Based on the characteristics of the creep curves and the nonlinear fittings of the relationships between stress and strain,strain and time,a unsaturated creep model including suction-stress-strain-time was established.The prediction accuracies of 3 empirical unsaturated creep models were compared.The results show that the whole creep process of weak intercalated soils can be predicted by the improved Mesri creep model by and large.Although the prediction values deviate from the experimental values when the deviator stress is higher,its prediction accuracy is basically acceptable in engineering practice.The accuracy of the proposed unsaturated creep model in predicting the creep behaviors of weak intercalated soils is lesssatisfactory.The predicting effect of the improved Singh-Mitchell creep model is the worst.
出处
《中国公路学报》
EI
CAS
CSCD
北大核心
2016年第4期22-29,共8页
China Journal of Highway and Transport
基金
国家自然科学基金项目(41502278)
中国博士后科学基金项目(2015M582588)
湖北省交通运输厅科技项目
中央高校基本科研业务费专项资金项目(310826151054)
关键词
道路工程
非饱和蠕变
蠕变模型
碎屑土夹层
基质吸力
road engineering
unsaturated creep
creep model
weak intercalated soil
matrix suction
