Abstract
Disposal of high-level radioactive waste (HLW) deep underground is one of the most challenging research subjects in rock engineering. In China, Beishan granite is usually chosen as host rock for the construction of the HLW repository. In this study, mechanical tests are conducted on Beishan granite and the stress-strain state during the complete failure process is analyzed by numerical simulation. The results show that the tensile strength and uniaxial compressive strength of Beishan granite are 8.66 and 162.9 MPa, respectively. Dilatancy appears when the stress reaches about 81% of the peak strength. Heterogeneity is introduced by Weibull distribution in numerical simulation. With the increase of homogenization degree, the degraded elements are more easily to concentrate locally. Based on experimental and numerical simulation results, it is noticeable that the sample volume is basically in the state of compaction before reaching the peak strength. The elements are more likely to show expansion, and the splitting failure dominates the destroy mode when the confining pressure is relatively low. With increasing confining pressure, more and more degraded elements are concentrated in the shear band, which develops from the surface to the interior of the sample during loading. Therefore, the granite shows ductile mechanical response characteristics when the confining pressure is relatively high. The results are instructive for the construction of the repository.
Highlights
High-level radioactive waste (HLW) is one of the most harmful pollutants in the world
It is reported that Beishan granite is chosen as the host rock of a HLW repository in China [1,2,3]. erefore, understanding the mechanical response and deformation behavior of Beishan granite is of significant importance for the safety and longterm stability of a repository
Micropores and cracks are distributed randomly inside rocks. ese individual components behave in different mechanical responses, leading to different deformation behaviors. erefore, the stress and strain states can be dominated by the spatial distribution of these individual components during loading [35]
Summary
High-level radioactive waste (HLW) is one of the most harmful pollutants in the world. Granite, characterized by low permeability and high strength, is a potential host rock for HLW. Oda et al studied the evolution of stress-induced cracks and failure mechanism in terms of the Advances in Civil Engineering invariants of crack tensor. It demonstrates that the density of the stress-induced cracks increases linearly with increasing inelastic volumetric strain [11]. Erefore, the stress and strain states can be dominated by the spatial distribution of these individual components during loading [35]. To solve this problem, the Weibull Sample no.
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