Numerical modeling of coupled thermo-mechanical response of a rock pillar

Understanding the rock mass response to excavation and thermal loading and improving the capability of the numerical models for simulating the progressive failure process of brittle rocks are important for safety assessment and optimization design of nuclear waste repositories. The international cooperative DECOVALEX-2011 project provides a platform for development, validation and comparison of numerical models, in which the Aspo pillar stability experiment (APSE) was selected as the modeling target for Task B. This paper presents the modeling results of Wuhan University (WHU) team for stages 1 and 2 of Task B by using a coupled thermo-mechanical model within the framework of continuum mechanics. The rock mass response to excavation is modeled with linear elastic, elastoplastic and brittle-plastic models, while the response to heating is modeled with a coupled thermo-elastic model. The capabilities and limitations of the model for representation of the thermo-mechanical responses of the rock pillar are discussed by comparing the modeling results with experimental observations. The results may provide a helpful reference for the stability and safety assessment of the hard granite host rock in China's Beishan preselected area for high-level radioactive waste disposal.