变性土的膨胀收缩特点及影响因素

研究了中国西南地区变性土的胀缩特性、形态学证据及主要影响因素．结果表明，变性土的线性膨胀系数（ＣＯＬＥ）一般高于０．０９，胀缩度大于４０％，塑性指数高于其它土壤．强烈的胀缩作用反映在土体中存在大量裂隙，裂纹和粘粒集结体。变性土矿物组成以蒙脱石为主，一般高于３５％．其微结构体表现为“曲片状、密集、胶结”形式的面—面叠聚体，因此表现出极高的膨胀潜势．

SWELL-SHRINK PROPERTIES AND INFLUENCING FACTORS OF VERTISOLS

Vertisols in South-Westerm China were collected for the studies of swell-shrink properties,morphology evidence and main influencing factors. The studies showed a higher COLE value and swell-shrink degree than 0.09 and 40% respectively. Powerful swell-shrink potenhal led to the formation of unique micromorphology features, such as voids being mainly fissures, hairline cracks and plasma seperations including asepic, insepic, masepic, lattisepic, vosepic and shelscpic. The high swell-shrink capacity relied on the high clay content, but more on the 2: 1 type clay minerals. Further, a special microstructure of "curve-assemble, concentrated, cementation" also had very large effect on swell-shrink potential.