Numerical analysis of thermal stress induced by solar radiation in concrete-faced rockfill dams

Based on the dual mortar method within the framework of computational contact mechanics, the transient heat conduction theory with nonconforming meshes is derived. A new thermo-mechanical coupled method is proposed to account for the temperature-induced stress and nonlinear contact behavior in concrete-faced rockfill dams (CFRDs). It is implemented numerically in the authors' in-house finite element code and then used to simulate an ideal CFRD under the solar radiation effect. The numerical results indicate that the solar radiation in summer can cause a significant temperature increase to the concrete face above the reservoir water. The maximum temperature reaches up to 51.6 ℃ and hence contributes a considerable additional value to the axial extrusion stress of the concrete face. The maximum stress is 22.3 MPa and occurs at the central valley near the dam top. The high values of extrusion stress are located at a thin layer near the outer surface. The numerical phenomenon coincides with the common features of extrusion damage from the practical CFRDs, confirming that the thermal stress induced by the summer solar radiation is one of the major factors causing extrusion damage.