排水条件下吹填软土蠕变特性  

Creep characteristics of blown soft soil under drainage condition

作　　者：杨爱武 杨少朋 张兆杰[2] YANG Ai-wu;YANG Shao-peng;ZHANG Zhao-jie(School of Environmental Science and Engineering,Donghua University,Shanghai 201620,China;Tianjin Key Laboratory of Soft Soil Characteristics and Engineering Environment,Tianjin Urban Construction University,Tianjin 300384,China)

机构地区：[1]东华大学环境科学与工程学院,上海201620 [2]天津城建大学天津市软土特性与工程环境重点实验室,天津300384

出　　处：《长安大学学报（自然科学版）》2023年第4期29-39,共11页Journal of Chang’an University(Natural Science Edition)

基　　金：国家自然科学基金项目(51978440,42177119);中央高校基本科研业务费专项资金项目(2232021A-07)。

摘　　要：为深入了解排水条件下吹填软土的蠕变变形和黏滞特性变化规律,对沿海地区软土地基的长期沉降进行合理预测。以天津滨海吹填软土为研究对象,利用三轴流变仪开展一系列的蠕变试验,分析不同排水条件、围压、固结比和初始静偏应力对其蠕变变形的影响,并在此基础上探讨排水条件下黏滞系数的变化规律,构建相应预测模型,同时,利用试验数据对计算结果进行验证。最后给出排水条件下考虑围压和时间等因素吹填软土蠕变变形的预测公式,构建不同蠕变变形阶段黏滞系数的预测模型,并验证模型的可行性。研究结果表明:排水和增大围压、固结比均可有效弱化吹填软土的蠕变效应,初始静偏应力的影响则存在临界值,小于该值时,蠕变变形减小,反之,蠕变变形明显;排水蠕变过程中黏滞系数随围压和固结比的增大而增大,且在小偏应力作用时,呈指数增长趋势,大偏应力作用时,增长幅度近乎线性且速率缓慢,而随初始静偏应力的增大而近乎线性减小;不同蠕变变形阶段,黏滞系数的表现存在差异性,其中线性黏弹与线性黏塑阶段,黏滞系数仅为时间函数,而非线性黏塑阶段,黏滞系数同时为时间和应力函数。研究成果可为吹填软土场地施工提供参考。To gain insight into the changing patterns of creep deformation and viscous properties of blown softsoils under drainage conditions,and to make effective predictions of long-term settlement of soft foundations incoastal areas.A series of creep tests were conducted using triaxial rheometer with Tianjin Binhai blown soft soil asthe research object,and the effects of different drainage conditions,surrounding pressure,consolidation ratio andinitial static deflection stress on its creep deformation were analyzed,and on this basis,the change law of viscoushysteresis coefficient under drainage conditions was explored,and the corresponding prediction model wasconstructed,meanwhile,the calculated results were verified by using the test data.Finally,a prediction formula for creep deformation of blow-filled soft soils under drainageconditions considering factors such as surrounding pressure and time was given,a prediction model for thecoefficient of viscosity at different creep deformation stages was constructed,and the feasibility of the model wasverified.The results show that drainage,increasing confining pressure,and consolidation ratio can effectively weaken the creep effect of dredgerfill soft soil.The effect of initial static deflection stress has a critical value,which reduces creep deformation whenit is less than this value,and on the contrary,creep deformation is obvious.In the process of drainage creep,theviscosity coefficient increases with the increase of confining pressure and consolidation ratio,and shows anexponential growth trend under the action of small deviatoric stress,the increase range is almost linear and therate is slow under the action of large deviatoric stress.It decreases almost linearly with the increase of the initialstatic deviatoric stress.The research results can provide reference for the construction of soft soil sites.7 tabs,17 figs,22 refs.

关 键 词：道路工程 吹填软土 排水条件 固结比 蠕变变形 黏滞系数 

分 类 号：U414[交通运输工程—道路与铁道工程]