Study on Deformation Characteristics of Gate Dam and Earth–Rock Dam Systems with Deep Overburden

Gate dam and earth–rock dam systems have many advantages, such as minimal ecological impact and good terrain adaptability, making them the preferred dam type for low-head, high-flow river areas with thick overburden layers. This study, based on an ongoing construction project, pioneers a comprehensive three-dimensional stress–deformation characteristic analysis of a gate dam and earth–rock dam system. The results indicate that the spatial non-uniformity of dam deformation is significant, with the earth–rock dam section exhibiting greater deformation than the gate dam section, which is related to the uneven distribution of dam loads and soil layers. Joint displacements in the gate dam section are larger on the two banks, while deformation consistency is better in the central section. In addition, the lack of coordination between the deformation of the cutoff wall and the overlying soil layer results in significant bending stress on the cutoff wall, causing a tensile state in the top of the cutoff wall. Due to the gravitational force of the top earth–rock dam, the underground continuous wall exhibits an uneven settlement deformation pattern. Additionally, the strong constraint effect of the gravity-retaining wall above it leads to the formation of tensile stress zones at the top and bottom of the underground continuous wall within a certain range. This study effectively identifies the mutual influences among the components of the gate dam and earth–rock dam system, obtains the spatial deformation characteristics of the mixed dam structure, accurately locates the weak zones in the dam system, and provides important references for engineering design improvements.