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金佳旭, 秦志发, 刘磊, 万勇, 王静, 左胜浩. 工业固废-水泥固化腐殖土的力学响应和微观机制[J]. 岩土工程学报. DOI: 10.11779/CJGE20230780
引用本文: 金佳旭, 秦志发, 刘磊, 万勇, 王静, 左胜浩. 工业固废-水泥固化腐殖土的力学响应和微观机制[J]. 岩土工程学报. DOI: 10.11779/CJGE20230780
Mechanical response and micro-mechanism of humus soil solidified by industrial solid waste-cement[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20230780
Citation: Mechanical response and micro-mechanism of humus soil solidified by industrial solid waste-cement[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20230780

工业固废-水泥固化腐殖土的力学响应和微观机制

Mechanical response and micro-mechanism of humus soil solidified by industrial solid waste-cement

  • 摘要: 为了推动腐殖土在岩土工程领域的资源化利用,采用工业固废(包括生物质飞灰、电石渣和磷石膏)协同水泥对腐殖土进行固化处理。本文以中国广东省某陈旧型简易垃圾填埋场开采的腐殖土为研究对象,通过常规三轴试验、干湿和冻融循环试验、扫描电镜(SEM)、X射线衍射(XRD)、傅立叶红外光谱(FTIR)和压汞(MIP)测试探究了工业固废-水泥固化腐殖土的三维力学特性、耐久性能及微观机制。试验结果表明:随着Po-b(即工业固废替代水泥的比率)的增加,试样偏应力与轴向应变的关系逐渐由应变软化向应变硬化过渡。三元工业固废的适当掺入(Po-b为25 %~50 %)有利于减缓干湿循环作用下工业固废-水泥固化腐殖土试样的劣化速率,而纯水泥固化腐殖土试样表现出相对优异的极限偏应力和抗冻性。微观结构分析表明大量钙矾石晶体和C-(A)-S-H凝胶等产物的生成增强了腐殖土颗粒之间的粘结的同时填充了微观孔隙。研究结果可为垃圾填埋场开采的腐殖土修复及再利用提供理论依据。

     

    Abstract: To advance the resource utilization of humus soil within the realm of geotechnical engineering, industrial solid waste materials (encompassing biomass fly ash, carbide slag, and phosphogypsum) cooperated with cement was used in this paper to solidify the humus soil. In this paper, humus soil mined from an obsolete simple landfill in Guangdong Province, China was solidified by industrial solid waste-cement. Then mechanical properties, durability and the underlying microscopic mechanisms were investigated by conventional triaxial tests, wet-dry and freeze-thaw cycling tests, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and mercury intrusion porosimetry (MIP) tests. The results showed that with the increasing of Po-b (i.e., the replacement ratio of cement by industrial solid waste), the relationship between deviatoric stress and axial strain of the samples gradually transitioned from strain softening to strain hardening. The appropriate incorporation of ternary industrial solid waste materials (ranging from 25 % to 50 % for Po-b) was beneficial in slowing down the deterioration rate of industrial solid waste-cement solidified humus soil samples under the action of dry-wet cycles. Furthermore, the cement-solidified humus soil samples exhibited excellent ultimate deviatoric stress and frost resistance. Microstructural analyses showed that a large number of reaction products such as ettringite crystal and C-(A)-S-H gel enhanced the bonding between humus soil particles and filled in the microscopic pores. The research results provide a theoretical foundation for the restoration and reuse of humus soil mined from landfill sites.

     

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