非饱和湿陷性土与湿胀性土分别具有亚稳态孔隙比结构和超稳态孔隙比结构,广义吸力是维持这种结构稳定的主要因素。随着广义吸力的丧失,两种结构均处于一个不稳定的孔隙状态,土体会向一个更加稳定的孔隙比结构发展。超孔隙比结构孔隙比增大,土体产生膨胀,亚稳孔隙比减小,土体产生收缩。基于这一稳态孔隙比理论,建立了广义吸力丧失引起的孔隙比的增量方程,来统一考虑非饱和土的湿陷性和湿胀性变形特性,并通过经典试验数据验证了增量方程的合理性。
The unsaturated soils upon wetting may swell or collapse depending the soil types or soil's void ratio.The particle structure of the unsaturated soil is considered to be in sub-stable and super stable states depending on its void ratio.Both the meta-stable and super stable states are maintained by the suction.The sub-stable and super stable structure becomes unstable upon wetting because of the suction reduction.There may exist a stable state that neither swelling nor collapsing will happen upon wetting.Employing the concept of stable state void ratio,a general formula is obtained which can describe both the swelling and collapsing behavior of the unsaturated soil.