Lifetime Prediction of Pvc-P Geomembranes Immersion in Water at Elevated Temperatures

Abstract

Plasticized polyvinyl chloride (PVC-P) geomembranes (GMBs) are applied as anti-seepage materials in membrane-faced rockfill dams and pumped storage power stations. Assessing their service life to ensure durability during operation is crucial. This study conducted accelerated aging tests on three PVC-P GMBs immersion in water, along with axial tensile tests to investigate the degradation of mechanical properties. The degradation model was constructed using the Arrhenius equation, and the service life was predicted based on this model and failure criterion. The prediction model’ accuracy was verified using test data collected over 180 days at 20 °C. The results demonstrate that the service life of PVC-P GMBs is influenced by reservoir water temperature, plasticizer content, and thickness of GMBs. Elevated temperatures accelerate the loss rate of plasticizers. Specifically, at 20 °C in a water environment, the service lives of Materials A and B with identical thicknesses were 49.05 and 153.76 years, respectively. This suggests that increasing the initial plasticizer content and enhancing its structural stability can significantly extend the service life. Furthermore, Material C, which has a composition similar to Material B but with increased thickness, exhibited a predicted service life of 181.30 years, indicating that greater thickness can effectively reduce the migration rate of plasticizers. The findings provide a theoretical basis for evaluating the service life of PVC-P GMBs in reservoir bottom and below dead water level applications during operation.

Keywords: PVC-P geomembrane, Break stress, Break strain, Arrhenius model, Service life