Laboratory Testing and Numerical Modeling of Creep Behavior of HDPE Geomembranes under Multistage Loading

Abstract

Abstract Geomembranes are essential impermeable materials commonly employed in the fields of hydraulic engineering and geoenvironmental engineering. However, their long-term operation may result in significant creep deformation, particularly under high loads. This paper mainly presents the effect of loading mode on the creep characteristics of high-density polyethylene (HDPE) geomembranes. A series of creep tests of geomembranes under multistage loading were conducted and compared with single loading creep tests. Under multistage loading, creep strain increased in a step-like manner. When the cumulative load level is lower than 50 %, the creep of geomembranes can attain a stable state. When the cumulative load level attains 60 %, the creep may enter a constant-rate creep stage. Compared with single loading creep, the creep under multistage loading attained a stable state earlier for a relatively low load level, and the deformations were smaller. The creep strain rate was significantly reduced at a constant-rate creep stage for a relatively high load level. The multistage loading was beneficial to the creep deformation control of geomembranes. Furthermore, an enhanced creep model was proposed to describe the creep behavior under multistage loading, including the stable state and constant-rate creep stage. The predictions were in good agreement with the experimental data.