冻融循环对固化污泥力学及微观结构特性影响

发布时间：2018-05-07 14:49

本文选题：固化污泥 + 冻融循环　；参考：《岩土力学》2016年05期

【摘要】：冻融循环作用会改变固化污泥工程特性,影响固化污泥堆体稳定及安全。在封闭系统下对固化污泥进行冻融循环试验,每经历一次冻融循环,就测定固化体的无侧限抗压强度、渗透系数等工程指标,并根据试验结果选取试样进行扫描电镜和压汞试验。研究结果表明:第1次冻融循环作用使固化污泥强度衰减30%,渗透系数增大80%,随后变化幅度逐渐降低;经过约6次冻融循环后,固化污泥强度衰减幅度高达50%,渗透系数增加约1个数量级,随后基本保持恒定,渗透系数的变化较无侧限抗压强度变化表现出微弱的滞后性。随着冻融循环次数的增加,固化污泥孔隙体积逐渐增大,固化污泥强度逐渐降低,渗透系数逐渐增大。在封闭系统下,固化体内部水分结冰引起的总膨胀体积恒定,固化污泥内部水分分布均匀。当冻融循环作用达到一定次数后,孔隙体积不再持续增大,只是在空间上重新融合分布,使各参数逐渐达到恒定状态。研究成果对寒区污泥固化填埋的安全处理处置提供技术参数和指导。
[Abstract]:Freeze-thaw circulation will change the engineering characteristics of solidified sludge and affect the stability and safety of solidified sludge. The freeze-thaw cycle test of solidified sludge was carried out in a closed system. Every freeze-thaw cycle, the unconfined compressive strength, permeability coefficient and other engineering indexes of the solidified sludge were measured. According to the test results, the samples were selected for scanning electron microscopy and mercury injection test. The results show that the first freeze-thaw cycle attenuates the strength of solidified sludge by 30%, increases the permeability coefficient by 80%, and decreases gradually after about 6 freeze-thaw cycles. The attenuation range of solidified sludge strength was as high as 50, the permeability coefficient increased by about 1 order of magnitude, then remained constant, and the change of permeability coefficient showed a weak hysteresis compared with the change of unconfined compressive strength. With the increase of freeze-thaw cycle, the pore volume of solidified sludge increases, the strength of solidified sludge decreases and the permeability coefficient increases. In the closed system, the total expansion volume of solidified sludge caused by water icing is constant, and the moisture distribution of solidified sludge is uniform. When the freeze-thaw cycle reaches a certain number of times, the pore volume will no longer continue to increase, but only in the space re-fusion distribution, so that the parameters gradually reach a constant state. The research results provide technical parameters and guidance for the safe treatment and disposal of sludge solidified landfill in cold area.
【作者单位】：辽宁工程技术大学力学与工程学院;中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室;
【基金】：中科院院地合作项目(武新管科创[2014]2号) 中国科学院学科交叉与合作创新团队项目(人字(2013)47号)~~
【分类号】：X703

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