冻融循环作用下城市污泥固化土三维力学特性及其破坏准则  

Three-dimensional mechanical properties and failure criterion of municipal solidified sludge under freeze-thaw cycles

作　　者：杨爱武 徐彩丽[2] 郎瑞卿 王韬 YANG Ai-wu;XU Cai-li;LANG Rui-qing;WANG Tao(School of Environmental Science and Engineering,Donghua University,Shanghai 201620,China;Key Laboratory of Soft Soil Engineering Characteristics and Engineering Environment of Tianjin,Tianjin Chengjian 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：《岩土力学》2021年第4期963-975,共13页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.51978440,No.52008286);天津市科技计划项目(No.19JCZDJC39700,No.19JCQNJC06900);中央高校基本科研业务费专项资金资助(No.2232021A-07)。

摘　　要：为了研究城市污泥固化土在经过不同冻融循环次数后的强度和变形特性,通过真三轴试验,对CJYT-1型固化剂固化的污泥土进行了试验研究。得到了在经过冻融循环次数N=0、1、3、5、8、10后的应力-应变关系曲线及强度和变形特性,并分析研究污泥固化土的中主应力比b及冻融循环次数N对土体强度参数的影响。试验结果表明:冻融循环试验中,污泥固化土的无侧限抗压强度及密度都随冻融循环次数的增加而逐渐减小,在8次循环后变化减缓趋于稳定;黏聚力c’b代及内摩擦角φ’b都表现为随b增大而增大,与b=0相比,b=1时c’1、φ’1/增长率最大分别可达16.77%和12.3%;随着冻融循环次数N的增加,土体的破坏强度逐渐减小,破坏应力比Mb总体呈减小的趋势,试样剪胀现象变化不明显,黏聚力c’b代和内摩擦角φ’b随着冻融循环次数N的增大而减小。基于Lade-Duncan及Matsuoka-Nakai两个常用破坏准则,结合污泥固化土真三轴试验数据,提出并验证了适用于污泥固化土的破坏准则,并根据该准则的φ’b-b关系曲线分析了b值对其的影响。对比提出的破坏准则、Lade-Duncan和Matsuoka-Nakai破坏准则,试验结果更趋近于新提出的破坏准则。To study the strength and deformation of municipal solidified sludge after different freeze-thaw cycles,the sludge solidified by CJYT-1 solidifying agent was tested through true triaxial tests.The stress-strain relationship and the strength and deformation characteristics after freeze-thaw cycles number of 0,1,3,5,8,10 are obtained,and the influence of intermediate principal stress ratio b and the number of cycles N on the soil strength parameters(including cohesion c’and internal friction angleφ’)are studied.The results of the freeze-thaw cycle test show that the unconfined compressive strength and density of the solidified sludge gradually decrease with the increase of the number of freeze-thaw cycles,and the change slows down and stabilizes after 8 cycles.The cohesion c’b and the internal friction angleφ’b both increase with the increase of b.Compared with b=0,when b=1,the growth rate of c’1 andφ’1 can reach 16.77%and 12.3%,respectively.As the number of cycles N increases,the failure strength of the soil gradually decreases,and the failure stress ratio Mb generally decreases.The dilatancy of the specimen does not change significantly.The cohesion c’b and internal friction angleφ’b decrease with the increase of freeze-thaw cycles N.Based on the two commonly used,Lade-Duncan and Matsuoka-Nakai failure criteria,combined with the true triaxial test data of solidified sludge,a failure criterion suitable for solidified sludge is proposed,and theφ’b-b relationship curve of the criterion is analyzed.Comparing the failure criteria proposed in the article,Lade-Duncan and Matsuoka-Nakai failure criteria,the test results are closer to the failure criteria in the article.

关 键 词：冻融循环 污泥固化 三维力学特性 应力-应变关系 破坏准则 

分 类 号：TU431[建筑科学—岩土工程]