剑麻纤维改良MgO-GGBS碳化粉质黏土物理力学性质与微观机制  

Physical and mechanical properties and microscopic mechanisms of MgO-GGBS carbonated silty clay improved by sisal fiber

作　　者：蔡光华 李纪 王俊阁 邱金伟 张志华 夏威夷 陆海军 CAI Guanghua;LI Ji;WANG Junge;QIU Jinwei;ZHANG Zhihua;XIA Weiyi;LU Haijun(College of Civil and Engineering,Nanjing Forestry University,Nanjing 210037,China;Department of Civil and Environmental Engineering,Changjiang River Scientific Research Institute,Wuhan 430010,China;Jiangsu Environmental Engineering Technology Co.Ltd.,Nanjing 210019,China;School of Civil Engineering and Architecture,Wuhan Polytechnic University,Wuhan 430023,China)

机构地区：[1]南京林业大学土木工程学院,南京210037 [2]长江科学院水利部岩土力学与工程重点实验室,武汉430010 [3]江苏省环境工程技术有限公司,南京210019 [4]武汉轻工大学土木工程与建筑学院,武汉430023

出　　处：《林业工程学报》2024年第5期161-168,共8页Journal of Forestry Engineering

基　　金：长江科学院开放研究基金资助项目(CKWV20221015/KY);国家自然科学基金(41902286,52008363);岩土力学与工程国家重点实验室开放基金(SKLGME021029)。

摘　　要：为解决传统固化剂——水泥的能耗高和环境污染大等问题,本研究采用MgO-粒化高炉矿渣(GGBS)碳化加固粉质黏土,采用剑麻纤维改善固化土的抗裂性,探讨了纤维掺量和纤维长度对碳化改良土物理和力学性质的影响。结果表明:在相同纤维长度下,随纤维掺量增加,MgO-GGBS碳化固化土样的体积增长率、含水率和内摩擦角增加,而黏聚力先增加后减小,无侧限抗压强度先增大后减小最终趋于稳定,黏聚力和强度的峰值出现在0.4%纤维掺量处。在相同纤维掺量下,随纤维长度增大,MgO-GGBS碳化固化土样的体积增长率先减小后增大,在长度10 mm时达到最小;含水率几乎不变;强度先增加后趋于稳定,在长度5~10 mm时提升显著;破坏应变增加,但几乎不受纤维掺量影响;碳化含纤维土样的黏聚力与内摩擦角先增加后减小,并在长度10 mm时达到最大。基于试验结果,提出了剑麻纤维改良MgO-GGBS碳化土加固的机理概念图,揭示了碳化土体基于纤维交织作用、固定作用和填充作用的改良机制。用MgO-GGBS-剑麻纤维等低碳材料代替水泥能显著提高碳化固化粉质黏土体的处理效果和抗裂性能。研究成果将对促进工业固废GGBS和农业废弃纤维在加固软弱地基土中的应用提供理论指导,对岩土工程“双碳”目标实现具有重要意义。In order to solve the problems of high energy consumption and severe environmental pollution of traditional curing agents such as Portland cement,reactive magnesia(MgO)-granulated blast furnace slag(GGBS)was used to carbonize and improve silty clay,and sisal fibers were added to improve the cracking resistance of carbonated/solidified soil.The effects of fiber content and fiber length on the physical and mechanical properties of carbonated/solidified soil were studied.The results showed that,under the same fiber length,with the increase of fiber content,the volume growth rate,water content,and internal friction angle of MgO-GGBS carbonated/solidified soil samples increased.However,the cohesion first increased and then decreased.The unconfined compressive strength first increased and then decreased and finally tended to be stable,and the peak values of cohesion and unconfined compressive strength appeared when the fiber content was 0.4%.Under the same fiber content,with the increase of fiber length,the volume growth rate of MgO-GGBS carbonated/solidified soil samples first decreased and then increased,finally reaching the minimum as the fiber length was 10 mm.The moisture content remained almost constant.The unconfined compressive strength first increased and then tended to be stable,finally achieving the maximum when the fiber length was 5-10 mm.The failure strain increased with the increase of fiber length,but it was almost not affected by the fiber content.The cohesion and internal friction angle of carbonated fiber-containing soil samples first increased and then decreased finally reaching the maximum when the fiber length was 10 mm.Based on the results,a conceptual diagram of the reinforcement mechanism of MgO-GGBS carbonated soil improved by sisal fiber was proposed,and the improvement mechanism of carbonated soil based on the interweaving,fixing,and filling effects of fiber was revealed.The use of low-carbon materials such as MgO-GGBS-sisal fiber instead of Portland cement can significantly improve the trea

关 键 词：活性MgO GGBS 剑麻纤维 无侧限抗压强度 直剪强度 

分 类 号：TU43[建筑科学—岩土工程]