Study on the effects of hydrodynamic pressure on the dynamic stresses in slabs of high CFRD based on the scaled boundary finite-element method

As the anti-seepage bodies in concrete-faced rockfill dams (CFRDs), face slabs play a vital role in ensuring dam reliability; thus, the stresses acting on face slabs should be analysed in detail. Considering the importance of the hydrodynamic pressure on high CFRD, the hydrodynamic pressure should be calculated with accurate methods when assessing the safety of high (approximately 300 m) CFRDs in strong ground motion zones. The principal objective of this paper is to investigate the effects of hydrodynamic pressure on the face slab response of a 300 m high CFRD under seismic loads in different directions. A dynamic coupling method for the modelling of CFRD-reservoir systems based on an approach combining the finite-element method (FEM) and the scaled boundary finite-element method (SBFEM) is developed. The hydrodynamic pressure of an incompressible fluid, based on a semi-analytical SBFEM approach, is expressed in the form of a full added-mass matrix. Moreover, the distribution of the hydrodynamic pressure and the mechanism by which it influences the dynamic stresses in the slabs are investigated. It is revealed that hydrodynamic pressure influences the dynamic stress in face slabs through the frictional force between the cushion and the slabs and cannot be neglected in the dynamic analysis of a high CFRD.