A 5-Parameter Isothermal Creep Model for Polymeric Liners
Polymeric materials are commonly used as load-carrying components in different structural applications due to the ease of manufacture, installation and long lifetime properties. In civil and mining engineering applications, fast-setting thin polymeric liners are in demand as areal support elements in underground openings. The stability of the openings is maintained by polymeric liners that might sustain the constant loads due to the presence of wedge blocks. Therefore, their time-dependent mechanical response requires a better understanding. There is limited research conducted on the creep modelling of polymeric liners. In this basis, this research aims to construct a new isothermal general creep behaviour model for polymeric support liners. 1-day cured creep tests results of polymeric liner were used to derive a new creep model with a combination of both Norton-Bailey and Kelvin creep models. The proposed model was also compared to the widely used creep models in literature. Since the acting stress on the liner depends on the block weight in field applications and the block weights are variable, a general creep model is developed to simulate the field behaviour of the liner under a wide range of constant stress levels. The proposed general model provides representative equations with comparably lower standard errors and this model might be used as an input for future numerical model studies in this field.
Keywords - Time-dependent model, Creep, Tunnel, Rock support, Norton-Bailey, Kelvin.