利用扫描电子显微镜（SEM）和X射线衍射（XRD）试验研究了陇南地区十天高速公路沿线膨胀土的微观结构和矿物成分，并对该地区膨胀土膨胀性进行了判断。试验结果表明，该地区膨胀土颗粒基本呈无弯曲或有弯曲薄片状，即应为蒙脱石或蒙脱石伊利石混层矿物颗粒；薄片状矿物颗粒以层状面-面接触，各矿物颗粒间存在狭小缝隙；定性与定量分析了膨胀土的矿物组成，其中蒙脱石含量较少，伊利石、高岭石和石英含量较高。经判断得出陇南地区十天高速公路甘肃段沿线膨胀土为弱膨胀土。

The microstructure and mineral composition of the expansive soil along Shiyan to Tianshui expressway in Longnan District were analyzed though scanning electron microscope (SEM) experiments and X-ray diffraction (XRD) experiments, and the expansion properties of expansive soil in this district were analyzed. According to the experiment results, the expansive soil particles basically presented as laminas with or without bending, which showed the properties of montmorillonite mineral particles or mixed-layer mineral particles of montmorillonite and illite; Lamelliform mineral particles were contacted surface to surface, and there were small gaps among the mineral particles; The mineral composition of this expansive soil was analyzed qualitatively and quantitatively, which showed small property of montmorillonite and large property of illite, kaolinite and quartz. Based on the experiment results above, the expansive soil along Shiyan to Tianshui expressway in Longnan legion of Gansu province was judged as weak expansive soil.

甘肃省交通运输厅科研项目（2013-07）