摘要
富有机质土是地基处理领域中的常见软弱类土,传统波特兰水泥不仅环境污染大,而且受有机质的负面影响大。本研究采用石灰激发粒化高炉矿渣(CaO+GGBS)固化改良富有机质土,开展了不同有机质质量分数、固化剂掺量(质量分数)及养护龄期等条件下,石灰激发GGBS固化有机质土的物理化学及力学试验研究。结果表明:有机质质量分数的增加显著增大了试样破坏时的裂缝数量和宽度;但固化剂掺量的增加将减少试样破坏时的裂缝数量、增大裂纹宽度;试样无侧限抗压强度q_(u)与变形模量E_(50)均随有机质质量分数增加而降低,随固化剂掺量和养护龄期增加而增加,且固化有机质土的E_(50)与q_(u)呈较好的线性关系;固化土的含水率随有机质质量分数的增加而增加,但随养护龄期及固化剂掺量的增加而降低;试样的pH随有机质质量分数及固化剂掺量的增加而增加,随养护龄期的延长而降低,与养护龄期7~28 d的pH相比,养护28~56 d时的试样pH显著降低。与水泥固化富有机质土对比,CaO+GGBS固化有机质土的强度随有机质质量分数的增加而明显衰减,适用于地基加固强度要求不高的工程项目,且碱激发固化剂具有潜在的环境优势。最后,本研究提出了CaO+GGBS固化有机质土的改进方案,不仅有益于拓宽固化富有机质土的处理思路,而且有利于促进岩土加固技术降碳目标实现。
Organic-rich soil is a common soft soil in the field of foundation treatment. Previous studies have shown that ordinary Portland cement not only has great environmental pollution, but also is greatly affected by the negative influence of organic matter. The quicklime-activated granulated blast furnace slag(CaO + GGBS) was used to solidify and improve the organic-rich soil. The physicochemical and mechanical tests of the quicklime-activated GGBS solidified organic soil were carried out under the different conditions of organic matter content, binder content, and curing age. The results show that the increase in organic matter content and curing age leads to the increase in crack number and width. While with the increase in binder content, the number of cracks is reduced, but the width of cracks is increased. The unconfined compressive strength(q_(u)) and deformation modulus(E_(50)) of samples is decreased with the increase in organic matter content, but is increased with the increase in binder dosage and curing age. There is a good linear relationship between E_(50)and q_(u)of the solidified organic soil. The moisture content of solidified organic soil is increased with the rise in organic matter content, but it is decreased with the extent in curing age and the increase in binder content. The pH values of the samples is increased with the rise in organic matter content and binder dosage but decrease with the duration in curing age. Compared with the solidified samples cured for 7-28 d, the pH values of the solidified samples cured for 28-56 d are decreased significantly. Compared with the cement-treated organic-rich soil, it is found that the strength development of organic-rich soil improved by the CaO + GGBS mixing binder has an obvious attenuation with the increase in organic matter content. Meanwhile, this alkali-activated binder is suitable for engineering projects with low strength requirements of foundation reinforcement, and it has a potential environmental advantage. Finally, this study puts forward the
作者
钟煜清
蔡光华
刘松玉
李江山
王俊阁
ZHONG Yuqing;CAI Guanghua;LIU Songyu;LI Jiangshan;WANG Junge(College of Civil Engineering,Nanjing Forestry University,Nanjing 210037,China;School of Transportation,Southeast University,Nanjing 211189,China;State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China)
出处
《林业工程学报》
CSCD
北大核心
2022年第4期151-157,共7页
Journal of Forestry Engineering
基金
国家自然科学基金(41902286)
岩土力学与工程国家重点实验室开放基金课题(Z019026)
国家自然科学基金委与香港研究资助局联合科研资助基金(N_PolyU511/18)。
关键词
碱激发
粒化高炉矿渣(GGBS)
富有机质土
无侧限抗压强度
变形模量
alkali activation
ground granulated blastfurnace slag(GGBS)
organic-rich soil
unconfined compressive strength
deformation modulus
