石灰固化镉污染高岭土干湿循环特征的试验研究

基于不同干湿循环下的直剪、低温氮吸附试验及试样照片,研究了石灰固化镉污染高岭土的干湿循环特征。测试结果表明:1干湿循环对剪切强度影响显著。固化剂掺量为0%,5%,10%,15%,20%时,经过20次干湿循环其最大剪切强度分别降低44%,64.48%,86.06%,90.06%及95.42%;凝聚力分别降低62.2%,75.95%,93.95%,95.99%及98.85%;2试样孔隙分布特征曲线有明显的两个峰值,说明试样在两个孔隙宽度范围内集中;3当固化剂含量为0%,5%时,随着干湿循环次数的增加,裂隙发育明显并具有一定的"愈合"能力。当固化剂含量为10%,15%及20%时,土体呈整体性破坏,"脆性"现象明显。

Experimental Research on Characteristics of Solidified Cadmium-contaminated Kaolin using Lime under Wetting-drying Cycles

Kaolin are mixed with cadmium nitrate to produce artificial cadmium-contaminated kaolin. Cement is used to solidify the artificial cadmium-contaminated soil. The samples are made using the compaction method. The direct shear and pore distribution characteristics were tests and the change of the samples is recorded useScamera. The results of direct shear are show that the shearing strength has great changes. Though 20 times the wetting-drying cycles, the maximum strength shearing is decreased to 44%,64.48%,86.06%,90.06% ,95.42% and cohesion is decreased to 62.2%,75.95%,93.95%,95.99% , 98.85% at the amounts of lime of 0%,5%,10%,15%,20%, respectively. When the amount of curing agent is 0%,5% and 10%, the friction angle between 18°to 20°,there is no regularity. When the amount of curing agent is 15% and 20%, hasSdeclinedSmarkedly. The results of BET are shown that sample pore distribution cure has two obvious peak value, this is because the width of pore is concentration in two size. The pore width is varies from the amounts of lime to the cycles of wetting-drying. The pore width is decreasesSfirstly, andSthenSincreases at the amount of 0%, increased at the amount of 5% with increasing of cycle-index. The pore width is increasesSfirstly, andSthenSdecreases at the amount of 10%, 15% and 20% with the increasing of cycle-index. The results of the camera of wetting-drying cycles is shown that the samples had obvious fracture at the amount of 0% and 5%, the fracture is no obvious, but the integrity of samples is destroyed.