Parameter Sensitivity Analysis of Polyurethane Cutoff Walls for Earth Dams under Multifield Coupling

Abstract

Polyurethane (PU) cutoff walls have increasingly been used in earth dam reinforcement projects due to their excellent antiseepage properties, strong deformation capabilities, ease of construction, and environmental friendliness. However, the parameter sensitivity of earth dams with PU cutoff walls under stress–seepage field coupling has not been revealed. In this study, a three-dimensional finite-element (3D FE) model was developed based on the Jiulong Reservoir Dam prototype, and the accuracy of the model was verified through a scaled model test. Using the 3D FE model as a foundation, a series of two-dimensional finite-element (2D FE) models were then constructed to conduct a parametric study of earth dams with PU cutoff walls. The thickness, density, and position of the PU cutoff wall were selected as the sensitive factors, while the safety factor, impermeability, deformation characteristics, and von Mises stress of the earth dam and cutoff wall were selected as the evaluation indicators. The mechanical and seepage characteristics of the dam were analyzed under the condition of different sensitive factors. Furthermore, the sensitivity of the sensitive factors was ranked based on the orthogonal test program. The research results of this study can provide a theoretical basis for the optimization design method of PU cutoff walls in earth dam reinforcement projects to a certain extent. Polyurethane is a kind of building material synthesized by the chemical reaction of isocyanate and polyether. Its lightweight nature, toughness, and impressive mechanical strength make it an ideal choice for various engineering projects including but not limited to dam seepage prevention, airport pavement repair, and underground pipeline filling. This study utilizes an orthogonal experimental method to establish finite-element models of an earth dam featuring a polyurethane cutoff wall under the coupling effect of stress and seepage. By analyzing the mechanical and seepage characteristics of the dam under different sensitive factor conditions, the research results demonstrate the impact of these factors on the performance of the earth dam, providing a theoretical basis for the design method of polyurethane cutoff walls to a certain extent.