Impact of non-linear elastic behavior on bentonite density evolution at the FEBEX. (December 2020)

• Record Type: Journal Article
• Authors: Takayama, Yusuke
• Is Part Of: International journal of rock mechanics and mining sciences. Volume 136(2020)
• Publication Date: 2020-12
• Subjects: Bentonite -- FEBEX -- Unsaturated elasto-plastic constitutive model; Rock mechanics -- Periodicals; Soil mechanics -- Periodicals; Mining engineering -- Periodicals; Roches, Mécanique des -- Périodiques; Sols, Mécanique des -- Périodiques; Technique minière -- Périodiques; 624.151305
• DOI: 10.1016/j.ijrmms.2020.104538
• Languages: English
• ISSNs: 1365-1609

Abstract

Abstract: It is necessary to apply reliable numerical simulation techniques to assess the mechanical behavior of repositories for the long-term geological disposal of radioactive waste. Having a constitutive model that can describe the mechanical behavior of bentonite is key to such numerical simulations. In this study, the applicability of a linear-elastic constitutive model with a swelling term is examined, focusing on density heterogeneity of the in-situ full-scale engineered barrier experiment (FEBEX) in Grimsel. It was found that the constitutive model underestimates the density change. Therefore, the mechanical behavior was re-simulated with an unsaturated elasto-plastic constitutive model using the changes in degree of saturation as input data. Two-dimensional stress and dry density was reproduced. Highlights: Simulation method using unsaturated elasto-plastic constitutive model is developed. Simulation technique is validated using in-situ experimental data. Evolution of stress and heterogeneous dry density distribution is reproduced.