三峡库区秭归县膨胀土研究

Research on the expansive soil in Zigui County,the Three Gorges Reservoir region

秭归县膨胀土是继在三峡库区巫山县、奉节县和兴山县发现膨胀土之后发现的又一处膨胀土,从而揭示了三峡库区膨胀土的地域性。秭归县膨胀土与三峡其他地方的膨胀土一样发育于特殊的地质环境内,具有坡洪积成因和较均一土体结构。土的膨胀性主要取决于其中的蒙脱石,测试表明有效蒙脱石含量达18.67%,以中等混层比的伊利石/蒙脱石(I/S)混层矿物形式存在。土具有高塑限、高液限和低抗剪强度。判别表明,它达到了国内外膨胀土标准和界限。

The expansive soil in Zigui County is another discovery in the Three Gorges Reservoir region after the discovery of expansive soil in Wushan County, Fengjie County and Xingshan County, which discloses the locality feature of the expansive soils. The expansive soil, the same as the others in the Three Gorges Reservoir region, develops in the special geo-environment and with the Diluvial-to-Pluvial genesis and relatively uniform structure. The expansive property is mainly determined by the montmorillonite in it, whose content is about 18.67% by test and exhibiting in the form of mixed-layer mineral illite/ montmorillonite （I/S） with middle mixed-layer ratio. The soil has high plastic limit, high liquid limit and low anti-shearing intensity, and reaches the national and international standards and limits on expansive soil.