Numerical Investigation into Underwater Explosion–Resistant Performance of an Arch Dam Considering Its Transverse Contraction and Control Joints

Arch dams appear vulnerable to underwater-explosion (UNDEX) shock loadings due to their relatively thin bodies. Many seismic analyses have highlighted the significant nonlinear joint contact behavior in dynamic responses of arch dams. This paper examines the effects of the transverse contraction and control joints, particularly the combination of the two joint types, on the UNDEX-resistant performance of arch dams. The investigation takes the form of a numerical case study of a 141-m-high arch dam subjected to an UNDEX using ABAQUS/Explicit. A surface-interaction-based approach that can consider damage initiation, evolution, and ultimate failure of the shear keys was employed for the joint modeling. The results show that the shear keys undergo considerable shearing damage under a 50-kg trinitrotoluene-equivalent UNDEX, which is mainly distributed at the upper halves of the joint interfaces. The radial displacement of and tensile damage to the dam in the basic case are not strictly enveloped by those in the two extreme cases. The damage-preventing effect of the control-joint implementation seems somewhat less pronounced than expected. This study has identified the significant role of transverse joints in UNDEX-induced responses of arch dams. Extreme approaches to the joint modeling in arch dams do not necessarily produce extreme results for the UNDEX-resistant performance evaluation. The control-joint implementation should be reviewed on a case-by-case basis in design practices. The surface-interaction-based approach could probably be usefully and easily employed in engineering practices.