自由膨胀率是反映黏性土的膨胀性的指标之一，对判别膨胀土有较大参考价值。

Free swell is one of indexes in representing the expansibility of clayey soil and makes great valuable reference in the judgment of expansive soil.

双层堤基的渗透破坏首先是从黏性土盖层开始的.

Failure of double layer dyke foundation by seepage first begins from tenacious clay covering.

利用扫描电镜照片研究黏性土的微观结构是目前应用较为广泛的方法，但多数研究仍以定性为主，定量研究方法十分有限。

SEM has been widely used to study the microstructure of clayey soil. Other than quantitative methods, most of them were qualitative methods.