Numerical simulation and experimental study on coordinated deformation of core-plinth structure under extreme canyon conditions

The steep valley core-plinth is prone to shear failure, and the performance of the connection between the asphalt concrete core (ACC) and the plinth is related to the overall seepage control safety of the dam. In this study, steep slope control groups with slopes of 71°, 76°and 81°were designed. On the basis of considering the extreme conditions in the specification, the research scheme also makes further exploration on the valley situation steeper than the specification value. Arc joints and flat joints are provided for two types of contact. Combined with the joint model test, the connection behavior between the ACC and the plinth under large shear displacement and high water pressure was discussed. Furthermore, numerical methods are employed to assess the adaptability of various core joint structures in extreme valley conditions. The results show that: (1) Both joint forms can ensure the safety of the anti-seepage system; (2) The overall stress level of arc joint is higher than that of flat joints and is more susceptible to variations in bank slope. The stress level in the core ranges from 0.3 to 0.4 (3) Appropriately reducing the embedded depth and the joint amplification angle is beneficial to alleviate the local shear effect. Corresponding to θ = 60°, D = 0.1 m, the core has the best performance. (4) For flat joint, expanding the joint's contact surface can reduce the ACC's shear effect. The research results lay a technical foundation and reference for the joint optimization of engineering under extreme river valley conditions.