Dynamic analysis of thermal crack propagation in RCD dams considering rotational component of ground motion

Abstract

In design and construction of the Roller-Compacted Concrete dams (RCD) controlling of the thermal cracks is a significant matter. In the construction of RCD dams, two types of internal and external concrete are used; Thermal cracks are occurred due to hydration of various cements in this type of dams. Ignorance of this issue can lead to crack formation in the susceptible points of the dams and also propagation of the cracks during an earthquake is a threat to the stability and durability of the dam. In this research, the behavior of the thermal cracks existed in the RCD dam body, is investigated through translational and rotational components of the seismic ground motion. Three-dimensional finite element model of the concrete gravity dam is built in ABAQUS software, and the model was subjected to 7 near-field earthquake records. After validation of the model, the propagation of the thermal crack existed in the dam body is evaluated using fracture mechanics criterion (J-integral criterion). The results of the finite element analysis show that the existence of the thermal cracks in the susceptible points of the dam, leads to propagation of these cracks during an earthquake. Especially, with considering the rotational component of the ground motion which has the significant contribution in the obtained values of the crack propagation criterion; This contribution is related to the intensity and frequency content of the earthquake, which can lead to an increase of the crack propagation energy up to 50 percent in some earthquake records.