Short-Term Creep Prediction Model for Composite Geomembranes with Varying Film Thicknesses

Composite geomembranes (GMs) are widely used in seepage projects, where their long-term deformation properties are critical for structural safety and stability. This study conducted a 90-day creep test to compare the deformation behavior of composite GMs with varying thicknesses. Based on the long-term creep data of the composite GMs, the average values of the model parameters and the variation rules of the coefficients of variation were analyzed. When the coefficients of variation for the creep exponent a and initial strain value b were both below 10%, a short-term empirical creep model across different thickness levels was established. The accuracy and applicability of the model were analyzed by comparing its results with the measured values. The results show that the long-term deformation behavior of the composite GMs across various thicknesses aligns with a logarithmic function containing thickness-dependent coefficients. Additionally, increasing film thickness leads to reduction in the final stabilized strain. The proposed short-term model based on experimental data demonstrated reasonable agreement between the model's 72 h fitted data and the experimental measurements. Consequently, this model may serve as a useful empirical method for predicting the long-term creep deformation of composite GMs.