Design method of polymer cut-off wall density for earth dams based on multi-objective optimization

Abstract

Polymer grouting cut-off reinforcement technology is a highly efficient, minimally invasive, and cost-effective solution that is widely used in earth dam reinforcement projects. However, the density of polymer materials used in these projects is typically determined based on engineering experience rather than an optimal design method that considers factors such as deformation coordination, strength reserve, and economy. To address this issue, a multi-objective optimization-based design method for the density of polymer cut-off walls has been developed. The method takes into account several factors, including the maximum variable displacement difference and the maximum horizontal gap length between the cut-off wall and the dam soil (deformation coordination index), the maximum Mises stress of the cut-off wall and the dam slope stability factor (strength index), and construction cost (economic index). Each index is normalized, and an index weight is introduced to linearly combine the normalized values. The resulting function is then used to optimize the density of the polymer cut-off wall. For an actual engineering project, the optimized polymer densities were found to be 0.232 g/cm3, 0.223 g/cm3, and 0.29 g/cm3, with different index weights. This method provides valuable guidance for the design of polymer cut-off wall density in earth and dam reinforcement projects.