DOI: 10.15986j.1006-7930.2018.06.005
对新疆昌吉地区粗颗粒盐渍土水泥改良后进行室内溶陷试验,研究水泥掺量和养护龄期对改良粗颗粒盐渍土溶陷特性的影响规律.结果表明:掺加水泥掺合料并养护一段时间后,粗颗粒盐渍土试样的压缩溶陷变形显著减小.不养护条件下,溶陷系数随水泥配合比增加无显著变化规律; 养护条件下,溶陷系数随水泥配合比增加呈指数衰减特征; 2%～4%水泥配合比溶陷性改良效果相对最优.不含水泥试样溶陷系数随养护时间增加呈波动形变化特征; 含水泥试样养护7 d后,溶陷系数有一定程度降低,而后趋于稳定数值; 养护时间7 d溶陷性改良效果相对最优; 相比养护时间,提高水泥配合比对溶陷性改良效果相对更优.不含水泥条件下,室内压实重塑粗颗粒盐渍土的溶陷系数亦小于0.01,为非溶陷性盐渍土,与现场浸水溶陷试验结果差异较大; 一定条件下可把粗颗粒盐渍土作为回填料进行碾压,进而通过提高粗颗粒盐渍土压实系数可显著改良地基土的溶陷性.
The influence of cement mixture ratio and curing age on the collapsibility of improved coarse-grained saline soil was studied by indoor collapsibility test on cement-improved coarse-grained saline soil taken from Changji area of Xinjiang. The results show that the added cement can make the collapsible deformation of soil specimen significantly decreased over a period of curing time. Under no curing condition, the coefficient of collapsibility has no obvious change law with cement mixture ratio increasing. However, the coefficient of collapsibility exponentially decreases with cement mixture ratio increasing after a period of curing time. The effect of the 2%-4% mixture ratio on the collapsibility treatment is best. The coefficient of collapsibility of soil samples with no cement shows a fluctuating variation with the curing time increasing. The coefficient of collapsibility of soil samples containing cement decreases after curing time of 7 days and then reaches a stable value. The effect of the curing age of 7 days on the collapsibility treatment is best. The improved effect on collapsibility by cement mixture ratio is better than that by curing age. The coefficient of collapsibility of compacted remolding coarse-grained saline soil with no cement is still lower than 0.01 and the soil samples are of no collapsibility, which has a big difference with the field immersion test results. Therefore, the collapsibility can be eliminated by using the coarse-grained saline soil as backfill and increasing the compaction factor.
