关键词: 膨胀特性, 膨胀土, 膨胀力, 干湿循环, 能量原理

Abstract: In order to study the effect of expansive characteristics of dry-wet cycling on expansive soils and the effect of dry-wet cycling on expansive rate change, the expansive soils collected at Lingshou County of Shijiazhuang City were taken as an experimental object. The free expansive rate test, non-load expansive test and expansive force test were carried out after dry-wet cycling by expansive instrument and consolidation instrument. The results showed that:① The unloaded expansion rate of expansive soil was related to water content and dry-wet cycle frequency. The smaller the water content was, the larger the expansion rate was. The larger the dry-wet frequency was, the smaller the linear expansion rate was.② The expansion deformation of the sample could be divided into three stages: initial expansion, accelerated expansion and uniform expansion.③ The expansive force of expansive soil decreased gradually after dry-wet cycle. The expansion process was described qualitatively and the expansion deformation formula based on energy dissipation was derived.

Key words: expansion and contraction characteristics, expansive soil, swelling force, dry-wet cycling, energy principle;