滞洪区路堤改良路基填土CBR试验研究

滞洪区亚粘土作路基基层、底基层填料土必须进行固化改良,本文采用石灰—粉煤灰、水泥—粉煤灰组合和水泥—石灰组合对其进行改良研究,以承载比CBR值作为指标,针对不同的压实度、固化剂不同配合比掺量开展了系列试验,并进行了分析和讨论.试验结果表明,三种改良填料土的抗压强度,随着压实度增加,分别先呈现不同比例的增长,但增加到一定值后,开始趋于平稳或弱有减少,可控制压实度在93%～96%之间,能兼顾施工质量与经济.水泥—粉煤灰组合改良土和石灰—粉煤灰土在水泥或石灰掺量一定时,其承载比随着粉煤灰掺量的增大呈先增大后减少;水泥—石灰组合和石灰—粉煤灰组合改良土在水泥或粉煤灰掺量一定时,其承载比也随石灰掺量的增大呈先增大后减少.三种改良土粉煤灰、石灰掺量都存在最佳配合掺量,基于试验结果,笔者就三种改良路基土给出了建议的配比.

The Study of CBR Test of Improved Soils of Embankment in FloodStorage and Detention Areas

The sub-clay of embankment in flood storage and detention areas should be im- proved when being used as the subbase course or the sub-subbase course. In this paper, three soil improvement methods, such as adding lime-fly, cement-fly ash or cement-lime, are proposed at one time. Based on CBR index,experiments on improving these soils arecarried out, aiming at analyzing and discussing the compaction and the mix ratios of hard- ening agent on the CBR index. Test showed that, along with the compactedness, CBR index of three improved soils gained and then fell slightly or levelled off, and the optimum com- pactedness was in 93% ~ 96%. When cement or line content maintained constant,the CBR index of the line-fly ash-soils and the cement-fly-soils respectively gained firstly and de- creased subsequently with fly ash content, and as cement or line content kept constant, the CBR index of the line-fly ash-soils and the cement-lime-soils respectively gained then de- creased subsequently with line content. There are the optimum addition of fly ash or line to three improved soils and based on that the author recommends the mix ratios.