Numerical analysis of wetting-induced deformation of rockfill dams

Wetting-induced deformation can lead to serious engineering hazards in rockfill dams. A new computational method for the determination of wetting-induced deformation is proposed here, which performs stress-deformation analysis of rockfill dams. Based on the results of triaxial wetting tests of rockfill materials, the effect of confining pressure on the wetting-induced volumetric strain was considered by revising the existing double-yielding surface model for rockfill materials. The nonlinear finite clement code was programed to perform stress-deformation analysis on a concrete-faced rockfill dam under the conditions of steady seepage and rise in tail water table using an elastoplastic constitutive model. The computational results demonstrate that (i) the wetting-induced deformation of rockfill materials under the phreatic line has significant effects on the distribution of deformation and stress in the dam body; (ii) along with the wetting-induced deformation, there is an increase in the settlement of the dam body and the horizontal displacement moves downstream. A relatively higher increment of compressive stress appears in the face slab and the peak values of both compressive and extensive stresses in the horizontal direction increase.