Multiscale modeling and analysis of shear response at dam-rock interfaces

点击翻译按钮获取中文摘要

The Dam Safety Act in Québec and its attendant regulation, which came into effect on April 11, 2002, require owners of high-capacity dams to regularly assess and monitor their structural behaviour under the effect of various loads. In this context, an appropriate understanding of dam-rock interaction is crucial for the assessment of the structural stability of concrete dams. The main objectives of this CRD research proposal are: (i) to develop an experimentally validated multiscale numerical model capable of predicting the values of apparent cohesion strength along dam-rock interfaces; (ii) to use the developed numerical model to carry out parametric analyses investigating the effects of apparent cohesion strength and dilation at irregular dam-rock interfaces on the sliding stability of actual concrete dams; (iii) to exploit the results obtained to develop new constitutive relations which can be implemented in software currently used at Hydro-Québec to conduct dam stability analyses as required by dam safety regulations; and (iv) to propose appropriate apparent cohesion strength values to be used for dam safety analyses if the obtained results clearly demonstrate that apparent cohesion strength is to be considered at dam-rock interfaces. The developed numerical models will be validated and calibrated using available results from shearing tests of drilled cores and larger scale square samples. Constitutive relationships will also be proposed and validated based on these results. In order to investigate dam-rock interfaces as close as possible to real dam site conditions, 3D profiles of actual rock foundation surfaces will be scanned in-situ using Light detection and ranging (LiDAR) technology. Four gravity dam monoliths with footprints corresponding to the scanned foundation surfaces will be modeled using finite elements. A series of parametric analyses of concrete-rock interfaces as well as 2D and 3D dam-rock systems will be conducted. Guidelines will be provided to characterize scale effects and the influence of joint roughness and apparent cohesion on the structural stability of the studied concrete dams.