A challenging dam structural analysis: large-scale implicit thermo-mechanical coupled contact simulation on Tianhe-II

Due to huge bulk volume and extremely complex geometrical and geological features, it is forbiddingly difficult to perform a dam structural analysis with even moderate geometry fidelity in engineering practices. We present a high resolution of engineering structural analysis of the first ultra-high concrete-faced rockfill dam in China. Mesh resolution is taken to be 20 cm along slab thickness for the bulk volume of 20M m^3 of the whole dam. The engineering problem is solved by considering nonlinear behaviors such as joints’ contact nonlinearity, creep deformation, and strong thermo-mechanical coupling, as well as blended continuous-discontinuous approximation, on a mesh model of 1.1 billion dofs using 16K CPU cores of Tianhe-II. The problem to be solved is a challenging non-positive definite, non-symmetric and ill-conditioned matrix problem. The simulation confirms in the first time that the sunlight temperature effect can contribute up to a contact stress increment of maximum 10.9 MPa and explains frequent extrusion damage observed for the dam. As model tests are difficult to perform for high dams, with this first success, we envision that extreme-scale simulation would pose broad impact on the safety evaluation of high dams in future.