DOI: 10.1016/j.tecto.2019.228277
论文题名: Impact of fluid pressure on failure mode in shear zones: Numerical simulation of en-echelon tensile fracturing and transition to shear
作者: Okamoto A. ; Fuse K. ; Shimizu H. ; Ito T.
刊名: Tectonophysics
ISSN: 00401951
出版年: 2020
卷: 774 语种: 英语
中文关键词: Distinct element method
; Effective normal stress
; En-echelon vein
; Failure mode
; Fluid pressure
; Shear deformation
英文关键词: Failure modes
; Numerical methods
; Numerical models
; Shear deformation
; Strain energy
; Transport properties
; Distinct element methods
; Effective normal stress
; En-echelon vein
; Fluid pressures
; Fracture pattern
; Tensile fractures
; Transient behavior
; Two-dimensional distinct element method
; Fracture
; computer simulation
; deformation mechanism
; effective stress
; failure analysis
; fluid pressure
; fracture mechanics
; numerical model
; shear zone
; stress field
; tensile strength
; two-dimensional modeling
英文摘要: En-echelon veins are a set of tensile fractures that develop during the initiation of shear zones under certain conditions, but factors that control fracture patterns remain unclear. In this study, we performed numerical simulations using the two-dimensional distinct element method to understand the influence of effective normal stress on the development of fractures during shear deformation. At low effective normal stress (10 MPa), dilation takes place at an angle of ≈40°–45° to the shear boundary, and en-echelon arrays of tensile fractures develop. In contrast, at high effective normal stress (150 MPa), en-echelon veins are not developed, but a distinct shear plane forms. A transient behavior characterizes intermediate effective normal stress (≈50 MPa): early tensile cracks are generated and then propagate to form larger brittle faults. In this case, the larger strain energy released in the later stage is due to the greater shear strength. Under crustal conditions, effective normal stress varies, due to the change in fluid pressure. Our results suggest that en-echelon veins are indicators of high fluid pressure, close to lithostatic conditions, i.e. effective normal stress close to zero, and that a transition of the failure mode from tensile to shear could occur in response to a dynamic change of fluid pressure during fracturing. © 2019 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170670
Appears in Collections: 气候变化与战略
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作者单位: Graduate School of Environmental Studies, Tohoku University, Japan, 6-6-20 Aramaki-aza-Aoba, Aoba-ku, Sendai, 980-8579, Japan; Institute of Fluid Science, Tohoku University, Japan, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan; Geotechnical Analysis Group, Advanced Analysis Department, Civil Engineering Design Division, Kajima Corporation, Japan, 6-5-30 Akasaka, Minato-ku, Tokyo, 107-8502, Japan
Recommended Citation:
Okamoto A.,Fuse K.,Shimizu H.,et al. Impact of fluid pressure on failure mode in shear zones: Numerical simulation of en-echelon tensile fracturing and transition to shear[J]. Tectonophysics,2020-01-01,774