ISSN 1000-3665 CN 11-2202/P

    侵蚀环境中碱渣-矿渣固化淤泥的力学性质

    Mechanical properties of the soft soil stabilized with soda residue and ground granulated blast furnace slag under the erosion environment

    • 摘要: 为扩展碱渣和矿渣等工业固体废弃物的资源化利用途径,以碱渣和矿渣为固化剂对淤泥进行固化处理,开展侵蚀环境条件下固化淤泥试样的表观和无侧限抗压强度等性质试验研究,探讨侵蚀溶液对固化淤泥的作用机理。研究表明,自来水和30 g/L的NaCl溶液浸泡时,标准养护28 d的固化土表面完整性较好,试样密度随浸泡时间的增加而增大;15 g/L的MgSO4溶液和NaCl-MgSO4混合溶液浸泡时,固化土表面受到明显侵蚀,随着浸泡时间的增加,侵蚀程度逐渐加深,试样体积、质量和密度呈减小趋势。当浸泡时间从28 d增至42 d时,自来水浸泡试样的无侧限抗压强度增大,溶液浸泡试样的无侧限抗压强度基本保持不变;浸泡导致试样的延性增强,抵抗变形的能力减弱。在浸泡时间相同的条件下,MgSO4和NaCl-MgSO4混合溶液浸泡时固化土强度约为自来水和NaCl溶液浸泡时强度的一半,抵抗变形的能力也较弱。钙矾石、水化氯铝酸钙等水化产物的形成使碱渣-矿渣固化淤泥抗NaCl侵蚀能力强,但由于侵蚀作用形成微观裂隙及疏松结构导致其抗MgSO4侵蚀能力较弱。

       

      Abstract: Soda residue (SR) and ground granulated blast furnace slag (GGBS) can be used as effective stabilizer for soft soil. However, the behavior of the SR-GGBS stabilized soil in the presence of soaking is seldom examined. In order to reveal the performance of SR-GGBS stabilized soft soil under the erosion environment, visual observations and unconfined compressive strength tests are conducted, and the scanning electron microscopy is used to discuss the mechanism. The results indicate that the samples in tap water or 30 g/L NaCl solution are intact, and the density increases with the soaking time. In 15 g/L MgSO4 solution or mixed solution, the samples are eroded obviously, and the volume, mass and density decrease with the soaking time. When the soaking time increases from 28 d to 42 d, the unconfined compressive strength of the samples in tap water increases, and the strength of the samples in solution remains unchanged. The soaking results in the increase of ductility and decrease of deformation resistance. At the same soaking time, the strength of the samples in MgSO4 solution or mixed solution is about half that in tap water or NaCl solution. The ability to resist deformation is also weak for the samples in MgSO4 solution or mixed solution. The formation of hydration products such as ettringite and calcium chloraluminate hydrate in SR-GGBS stabilized soil is helpfull to resist to NaCl erosion, while its resistance to MgSO4 erosion is weak due to the micro-cracks and loose structure. The results will contribute to the use of SR and GGBS as stabilizers for soft soil in the complex environment.

       

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