摘要
采用自主研发的新型固化剂对城市污泥进行固化处理,通过对污泥固化土进行冻融循环作用下的不固结不排水蠕变试验,探讨其在气候环境影响下的长期变形和强度发展特性.试验结果表明,污泥固化土抗剪强度随冻融循环次数的增加呈现先明显降低后趋于稳定的趋势.当施加偏应力小于污泥固化土结构屈服应力时,其蠕变历时曲线呈现衰减型蠕变形态,各级应力水平下的曲线整体态势相近;当偏应力水平达到破坏应力时,蠕变变形急剧增长.在其他条件相同的情况下,冻融温度越低,蠕变变形的速率越快,每级蠕变稳定时的变形量也越大.污泥固化土等时曲线具有显著的屈服点,t=0h时刻等时曲线与其他时刻曲线簇相比存在明显的离散现象,在此基础上,基于应力⁃应变对数曲线和等时曲线拐点法,先后建立了能够考虑冻融循环作用影响的污泥固化土蠕变模型及其长期强度预测公式,可为相关工程实践提供参考.
The municipal sludge was solidified with a new curing agent developed independently.Considering the impact of the climatic environment,we analyzed the long⁃term deformation and strength development properties of the solidified sludge by using a series of triaxial creep tests under freeze⁃thaw cycles.The experimental results show that with the number of freeze⁃thaw cycles increasing,the shear strength of the solidified sludge tends to reduce significantly first and then becomes steady.When the deviatoric stress applied to the soil samples was less than the yield stress of the solidified sludge,the duration curves of creep all presented an attenuated creep pattern.Moreover,the overall trends of the curves under different stress levels were similar.When the deviatoric stress level reached failure stress,the creep deformation increased sharply.When other conditions are the same,the lower the freeze⁃thaw temperature is,the faster the creep deformation rate will be,and the larger the amount of deformation will be when each level of creep is stable.The isochronous curves of the solidified sludge have an obvious yield point;compared with the curves at other times,the isochronous curve at t=0h shows an obvious discrete phenomenon.Based on the stress⁃strain logarithmic curves and the inflection point method of isochronous curves,a creep model of solidified sludge and its long⁃term strength prediction formula that can consider the effects of freeze⁃thaw cycles have been established,which can provide relevant engineering practice references.
作者
杨爱武
杨少坤
王峥
张先伟
王亚成
YANG Aiwu;YANG Shaokun;WANG Zheng;ZHANG Xianwei;WANG Yacheng(College of Environmental Science and Engineering,Donghua University,Shanghai 201620,China;Tianjin Key Laboratory of Soft Soil Characteristics and Engineering Environment,Tianjin Chengjian University,Tianjin 300384,China;State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China)
出处
《应用基础与工程科学学报》
EI
CSCD
北大核心
2023年第1期65-80,共16页
Journal of Basic Science and Engineering
基金
国家自然科学基金项目(42177119,51978440)
中央高校基本科研业务费专项资金(2232021A⁃07)。
关键词
污泥固化土
冻融循环
蠕变变形
历时曲线
等时曲线
长期强度
solidified sludge
freeze⁃thaw cycle
creep deformation
duration curve
isochronous curve
long⁃term strength
