Study of Gravelly Soil Core Material Using a Large-Scale Triaxial Wetting Test

Abstract

Wetting deformation has a significant impact on dam safety, and is one of the leading causes of the long-term deformation of dams. For dams to operate safely, it is crucial to precisely estimate the extent of wetting deformation using a reasonable calculation model. This study describes the wetting deformation behavior of gravelly soil core material observed at a hydropower station using a large-scale triaxial wetting test, and the process, characteristics, and mechanism of the wetting deformation are analyzed. The results show that the direction of the wetting deformation exhibits different behaviors influenced by the stress levels. Compared with the significant changes in the wetting direction observed under low stress levels, the changes in the wetting direction under high stress levels appears to lag behind those in wetting deformation. The source of wetting deformation is thought to be the weakening of a material when it encounters water. Thus, a new calculation model of the wetting deformation of gravelly soil core material is proposed. In this model, the wetting strain ratio is in an exponential relationship with the stress levels, and the new model is used to simulate the triaxial wetting test on the gravelly soil core material; its validity and practicability are further evaluated, providing a new computational approach for analyzing the wetting deformation behavior of dams.