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以粒化高炉矿渣粉-氧化镁(GGBS-MgO)固化铅污染黏土为研究对象,通过半动态淋滤试验,对GGBS-MgO在酸雨作用下的强度特性及溶出特性进行研究。通过对GGBS-MgO固化铅污染黏土半动态淋滤后pH值、针刺深度、无侧限抗压强度及浸出液中[Pb]、[Ca]、[Mg]元素浓度的测试,分析淋滤液初始pH值、掺量以及含铅不含铅对GGBS-MgO固化土强度特性的影响,讨论了初始淋滤液pH值、固化剂掺量对GGBS-MgO固化铅污染土累积铅、钙、镁溶出质量以及铅有效扩散系数的影响规律。结果表明,半动态淋滤试验使试样无侧限抗压强度qu较标准养护39d试样降低了2%~53%,且淋滤液初始pH=2对试样qu影响最大;在相同掺量、相同淋滤液初始pH值时,GGBS-MgO固化未污染土半动态淋滤后qu较水泥固化未污染土qu提高了12%~43%;且当固化剂掺量为18%时,固化铅污染土强度特性较水泥有明显优势,约为水泥固化铅污染土强度的1.3~1.8倍;且相同配比时,淋滤液初始pH=2表层的pH值约为pH=3、4、5、7的1/2;随着淋滤液初始pH值、半动态淋滤后qu及内部pH值的增加,针刺深度减小;针贯入阻力与qu存在幂指数关系。此外,累积铅、钙、镁溶出质量随着初始淋滤液pH值、固化剂掺量的增加而减少,在初始淋滤液pH=2时,Ai,Pb、Ai,Ca、Ai,Mg分别约为pH=3、4、5和7的29~222倍、1.7~4.4倍和12.0~80.3倍;固化剂掺量为12%时的累积溶出质量约是18%掺量时的1.1~2.0倍;铅有效扩散系数De随着初始淋滤液pH值的增加而降低,初始淋滤液pH=2时的De比pH=3~7的De高约3~5个数量级;且低于水泥固化铅污染土De,当初始淋滤液pH=7时,GGBS-MgO固化土De相比于水泥固化土低1~2个数量级。
Taking GGBS-MgO solidified lead-contaminated clay as the research object, the strength and dissolution characteristics of GGBS-MgO under acid rain were studied by semi-dynamic leaching test. Through the semi-dynamic leaching of GGBS-MgO solidified lead-contaminated clay, the initial leachate initial pH, the depth of needle penetration, the unconfined compressive strength and [Pb], [Ca] and [Mg] pH value, dosage and lead-free lead on the strength characteristics of GGBS-MgO solidified soil. The effects of initial leachate pH and amount of curing agent on lead, calcium and magnesium dissolved lead concentration in GGBS-MgO solidified lead And the influence law of effective diffusion coefficient of lead. The results show that the semi-dynamic leaching test can reduce the unconfined compressive strength qu of the sample by 2% -53% compared with the sample 39d, and the initial leachate pH = 2 has the greatest effect on the sample qu. , The same quaternary leaching rate of quaternized GGBS-MgO leached quaternary ammonium was 12% -43% higher than that of cement-bound uncontaminated soil when the same leaching solution initial pH value. When the amount of curing agent was 18% The strength of the contaminated soil has obvious advantages compared with the cement, which is about 1.3-1.8 times the strength of the cement-cured lead contaminated soil. When the same ratio, the pH of the leachate initial pH = 2 is about pH = 3, 4, 5, 7 1/2; With the initial pH value of the leachate, semi-dynamic leaching after qu and internal pH value increases, the depth of acupuncture decreases; pin penetration resistance and qu exist exponential relationship. In addition, the leaching quality of accumulated lead, calcium and magnesium decreased with the increase of the initial leachate pH and the amount of curing agent. At the initial leachate pH = 2, the contents of Ai, Pb, Ai, Ca, Ai and Mg were about 29 to 222 times, 1.7 to 4.4 times and 12.0 to 80.3 times that of pH = 3, 4, 5 and 7. The cumulative dissolution mass at 12% of curing agent was about 1.1 to 2.0 times that at 18% The effective diffusion coefficient De of lead decreased with the increase of initial pH value of leachate. De at the initial leachate pH = 2 was about 3 to 5 orders of magnitude lower than that of De = 3 ~ 7; and it was lower than that of cement-cured lead contaminated soil De, when the initial leachate pH = 7, GGBS-MgO soil De solidified soil compared to De cement 1 to 2 orders of magnitude lower.