水泥-粉煤灰-脱硫石膏固化铅污染土强度特性及预测方法

为了研究复合水泥材料固化铅污染土的强度特性,采用水泥、粉煤灰与脱硫石膏混合形成的固化剂(CFG)对铅污染土进行固化处理,基于正交试验的方法进行无侧限抗压强度测试,研究铅离子浓度与CFG掺量对土体强度特性的影响规律。结果表明:固化土的抗压强度随CFG掺量增加而增大,随铅离子浓度增加而降低;养护7 d前铅离子浓度和固化剂掺量对土体抗压强度的影响,前者大于后者,而7 d后后者大于前者;在3,7 d时2种因素对于土体的强度的影响均较小,在14 d时该影响大幅提升,到28 d时影响特别显著。结合试验成果,提出了基于养护龄期和CFG掺量的强度预测公式,研究成果可供从事铅污染土修复工作的科研人员参考。

Lead-contaminated Soil Solidified by Cement-Flyash-Gypsum- desulphurized:Mechanical Strength Characteristics and Prediction Method

Orthogonal unconfined compression test was conducted on lead-contaminated soil solidified by curing agent CFG (cement mixed with flyash and desulphurized gypsum) to investigate the strength characteristics of treated lead-contaminated soils varying with lead ion concentration and CFG dosage. Results reveal that the unconfined compressive strength of stabilized soils increases with the growth of CFG dosage, while reduces with the climbing of lead ion concentration. In the first seven days of curing, the effect of lead ion concentration is greater than that of curing agent dosage; after seven days, the influence of the dosage of curing agent is greater than that of lead ion concentration. At 3 d and 7 d of curing, the influences of both factors on soil strength are small, while at 14 d the influence greatly increases, and at 28 d, the effect is especially significant. Furthermore, the formula of strength prediction based on curing age and CFG dosage is proposed as a reference for the treatment of lead-contaminated soil.