石灰固化镉污染高岭土干湿循环特征的试验研究

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

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。

The wetting-drying cycles characteristics of lime solidified/stabilized Cadmium contaminated kaolin was investigated. The direct shear and low temperature nitrogen absorption test were employed to identify character- istics of wetting-drying of the contaminated clays. The change of the sample under wetting-drying cycles is recorded using camera. Test result of the direct shear show that 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. Test result of low temperature nitrogen absorption test show that the pore width is varies from the amounts of lime to the cycles of wetting-drying. The cam- eras are shown that the samples had obvious fracture at the amounts of lime at 0% and 5%, the fracture is no obvi- ous, but the integrity of samples is destroved at the amounts of lime at 10%, 15% and 20%.