On the Mechanisms of Impoundment-Induced Foundation Deformations of Super-High Arch Dams

Abstract

AbstractDuring the impoundment process of two super-high arch dams, Jingping and Xiluodu arch dams in China, significant width reduction up to 10–90 mm of the valleys and dams have been observed. It is indicated in this report that the width reductions essentially belong to plastic deformation and the mechanism behind the width reduction is related to the change of effective stress in the dam foundation induced by the impoundment. By comparing the numerical results with the measurements, the width reduction of the Jinping arch dam can be well described by poroplasticity theory as a continuum approach. It is shown that the difference between Biot’s effective stress and the plastic effective stress for yield condition plays a key role in the width reduction. The large width reduction of the Xiluodu arch dam, about 90 mm, cannot be described by the poroplasticity theory and may be related to Hubbert’s effective stress principle as a discontinuous approach.KeywordsHigh arch damValley width reductionEffective stressPoroplasticity