scholarly journals Tunnel Misalignment with Geostatic Principal Stress Directions in Anisotropic Rock Masses

2020 ◽  
Vol 43 (1) ◽  
pp. 123-138 ◽  
Author(s):  
Osvaldo Paiva Magalhães Vitali ◽  
Tarcisio Barreto Celestino ◽  
Antonio Bobet
Keyword(s):  
Principal Stress ◽  
Rock Masses ◽  
Anisotropic Rock ◽  
Stress Directions

Rotation of the principal stress directions due to earthquake faulting and its seismological implications

1995 ◽  
Vol 85 (5) ◽  
pp. 1513-1517
Author(s):  
Z.-M. Yin ◽  
G. C. Rogers
Keyword(s):  
Shear Stress ◽  
Normal Stress ◽  
Principal Stress ◽  
Stress Drop ◽  
Rotation Angle ◽  
Overburden Pressure ◽  
Rupture Area ◽  
Earthquake Faulting ◽  
Stress Directions ◽  
Before And After

Abstract Earthquake faulting results in stress drop over the rupture area. Because the stress drop is only in the shear stress and there is no or little stress drop in the normal stress on the fault, the principal stress directions must rotate to adapt such a change of the state of stress. Using two constraints, i.e., the normal stress on the fault and the vertical stress (the overburden pressure), which do not change before and after the earthquake, we derive simple expressions for the rotation angle in the σ1 axis. For a dip-slip earthquake, the rotation angle is only a function of the stress-drop ratio (defined as the ratio of the stress drop to the initial shear stress) and the angle between the σ1 axis and the fault plane, but for a strike-slip earthquake the rotation angle is also a function of the stress ratio. Depending on the faulting regimes, the σ1 axis can either rotate toward the direction of fault normal or rotate away from the direction of fault normal. The rotation of the stress field has several important seismological implications. It may play a significant role in the generation of heterogeneous stresses and in the occurrence and distribution of aftershocks. The rotation angle can be used to estimate the stress-drop ratio, which has been a long-lasting topic of debate in seismology.

FDEM numerical modeling of failure mechanisms of anisotropic rock masses around deep tunnels

2021 ◽  
pp. 104535
Author(s):  
Penghai Deng ◽  
Quansheng Liu ◽  
Xing Huang ◽  
Yucong Pan ◽  
Jian Wu
Keyword(s):  
Numerical Modeling ◽  
Failure Mechanisms ◽  
Rock Masses ◽  
Anisotropic Rock

Stress Path Tests with Controlled Rotation of Principal Stress Directions

2009 ◽  
pp. 516-516-25 ◽  
Author(s):  
JRF Arthur ◽  
S Bekenstein ◽  
JT Germaine ◽  
CC Ladd
Keyword(s):  
Principal Stress ◽  
Stress Path ◽  
Stress Directions

Design of a defence hole system for a shear-loaded plate

2003 ◽  
Vol 38 (6) ◽  
pp. 507-517 ◽  
Author(s):  
S. N Akour ◽  
J. F Nayfeh ◽  
D. W Nicholson
Keyword(s):  
Finite Element Analysis ◽  
Principal Stress ◽  
Pure Shear ◽  
Optimization Method ◽  
Optimum Size ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Search Optimization ◽  
Stress Directions ◽  
Circular Holes

Stress concentrations associated with circular holes in pure shear-loaded plates can be reduced by up to 13.5 per cent by introducing elliptical auxiliary holes along the principal stress directions. These holes are introduced in the areas of low stresses near the main circular hole in order to smooth the principal stress trajectories. A systematic study based on univariate search optimization method is undertaken by using finite element analysis (FEA) to determine the optimum size and location for an auxiliary defence hole system. The results are validated using RGB (red-green-blue) photoelasticity.

Analytical solution for tunnels not aligned with geostatic principal stress directions

2018 ◽  
Vol 82 ◽  
pp. 394-405 ◽  
Author(s):  
Osvaldo P.M. Vitali ◽  
Tarcisio B. Celestino ◽  
Antonio Bobet
Keyword(s):  
Analytical Solution ◽  
Principal Stress ◽  
Stress Directions

scholarly journals The ARMR Classification System and the Modified Hoek-Brown Failure Criterion Compared to Directional Shear Strength Models for Anisotropic Rock Masses

2019 ◽  
Author(s):  
Neil Bar ◽  
Charalampos Saroglou
Keyword(s):  
Shear Strength ◽  
Rock Mass ◽  
Failure Criterion ◽  
Classification System ◽  
Failure Criteria ◽  
Rock Masses ◽  
Anisotropic Rock ◽  
Anisotropic Rock Mass ◽  
Degree Of Anisotropy ◽  
Strength Models

The anisotropic rock mass rating classification system, ARMR, has been developed in conjunction with the Modified Hoek-Brown failure to deal with varying shear strength with respect to the orientation and degree of anisotropy within an anisotropic rock mass. Conventionally, ubiquitous-joint or directional shear strength models have assumed a general rock mass strength, typically estimated using the Hoek-Brown failure criterion, and applied a directional weakness in a given orientation depending on the anisotropic nature of the rock mass. Shear strength of the directional weakness is typically estimated using the Barton-Bandis failure criterion, or on occasion, the Mohr-Coulomb failure criteria. Directional shear strength models such as these often formed the basis of continuum models for slopes and underground excavations in anisotropic rock masses. This paper compares ARMR and the Modified Hoek-Brown failure criterion to the conventional directional shear strength models using a case study from Western Australia.

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