Fracture mechanics characterization of an anisotropic geomaterial

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• 作者：F. Barpi^a ; ^{fabrizio.barpi@polito.it} ; S. Valente^a ; M. Cravero^b ; G. Iabichino^b ; C. Fidelibus^b
• 关键词：Semi-Circular specimen under three-point Bending (SCB) ; Transversal isotropy ; Cohesive crack ; Non-linear fracture mechanics ; Fictitious crack model ; Argillites ; Size effect ; Fracture energy ; Apparent fracture toughness
• 刊名：Engineering Fracture Mechanics
• 出版年：2012
• 期刊代码：33_00137944
• 类别：ms
• 出版时间：April, 2012
• 卷：84
• 期：Complete
• 页码：111-122
• 文件大小：1266 K

摘要

Argillites are considered worldwide as potential host rock for high level radioactive waste given the low permeability and strong adsorption potential. However, the excavation of the galleries of a repository would produce a disturbed zone around the boundaries rich of new fractures which may enhance the conductivity of the rock along the gallery axis.

Several mine-by experiments have been performed in underground rock labs to investigate the features of the disturbed zone. In Mont Terri URL (Kanton Jura, Switzerland) the EZ-B experiment was specifically conceived for the measurement of excavation induced fractures around a small chamber. The host rock of the URL is a particularly compact and resistant argillite, known as the Opalinus Clay (OPA) excavated and OPA samples were subjected to fracture mechanics tests at the rock mechanics lab of IGAG-CNR in Torino, Italy. The tests aimed at the understanding aspects of the fracturing process occurring in OPA of Mont Terri, which may be considered a transversely isotropic geomaterial, whose planes of isotropy coincide with the bedding.