中文摘要：

通过半动态淋滤试验,研究淋滤液初始pH=2,4,7时水泥固化铅污染土的强度、微观和钙溶出特性。无侧限抗压强度试验及钙溶出率（CFRCa）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39 d试样降低了1%～42%；淋滤液初始pH=2时,CFRCa为pH=4或7时的2～7倍,而pH=4与7时qu及CFRCa差别均不明显；水泥掺量由12%提高到18%时,qu增大了35%～98%,CFRCa降低了40%～58%；固化铅污染土较固化未污染土,其qu小50%～68%,而CFRCa大29%～175%。试样无侧限抗压强度比qr（淋滤后试样qu/标准养护39 d试样qu）与CFRCa在双对数坐标下呈现良好线性关系：随CFRCa增大,qr减小,说明钙的溶出是控制固化污染土/未污染土强度的主要因素之一。X射线衍射、扫描电镜及压汞试验结果表明,高浓度铅抑制水泥水化/火山灰反应,固化铅污染土与固化未污染土孔隙分布分别呈单峰和双峰特征,固化铅污染土中铅形成Si-O-Pb结合体、PbAl2O4、CaPbO3等沉淀是铅固化稳定化的主要机理之一。

英文摘要：

The strength and microstructural characteristics of cement stabilized/solidified lead-contaminated kaolin clay are investigated. The leaching of calcium （Ca） is studied under the targeted leachant pH of 2, 4, and 7 via a series of semi-dynamic leaching tests. The results reveal that the unconfined compressive strength （qu） of the stabilized/solidified soils experiencing the semi-dynamic leaching tests is 1% to 42% lower than that of the soils cured for 39 days under standard conditions （SC）. The cumulative leaching fraction of Ca （CFRCa） at the leachant pH of 2 is 2 to 7 times greater than that at the leachant pH of 4 or 7. The difference in qu or CFRCa of the soils experiencing the semi-dynamic leaching tests at the lechant pH of 4 and 7 is marginal. When the cement content increases from 12% to 18%, qu increases by 35% to 98%; whereas CFRCa decreases by 40% to 58%. Furthermore, qu of the stabilized/solidified lead-contaminated soils is 50% to 68% lower, and CFRCa is 29% to 175% higher than that of the stabilized/solidified clean soils. An empirical equation is proposed for predicting the loss of unconfined compressive strength （i.e., ratio of qu obtained after leaching tests to that obtained at curing time of 39 days under standard conditions） using CFRCa. It is shown that the proposed method has high accuracy. The results of X-ray diffraction, scanning electron microscope, and mercury intrusion porosimetry analysis show that the relatively high concentration of Pb has remarkably retarded hydration/pozzolanic reactions in the stabilized/solidified lead-contaminated soils. Therefore, the strength development, leaching of Ca, and microstructural characteristics of the stabilized/solidified lead-contaminated soils differ from those of the stabilized/solidified clean soils in a notable manner.