Zonal disintegration mechanism of cross-anisotropic rock mass around a deep circular tunnel under dynamic unloading

2012 ◽  
Vol 60 (1) ◽  
pp. 15-22 ◽  
Author(s):  
X.P. Zhou ◽  
J. Bi
Keyword(s):  
Rock Mass ◽  
Zonal Disintegration ◽  
Circular Tunnel ◽  
Anisotropic Rock ◽  
Dynamic Unloading ◽  
Anisotropic Rock Mass ◽  
Deep Circular Tunnel

Numerical Simulation of Zonal Disintegration of the Surrounding Rock Masses Around a Deep Circular Tunnel Under Dynamic Unloading

2015 ◽  
Vol 12 (03) ◽  
pp. 1550020 ◽  
Author(s):  
Jing Bi ◽  
Xiao Ping Zhou
Keyword(s):  
Strength Criterion ◽  
In Situ Stress ◽  
Zonal Disintegration ◽  
Rock Masses ◽  
Circular Tunnel ◽  
Dynamic Unloading ◽  
Deep Rock ◽  
Zonal Disintegration Phenomenon ◽  
Nonlinear Unified Strength Criterion ◽  
Deep Circular Tunnel

A new numerical method, which is called the General Particle Dynamics (GPD) method, is proposed to investigate the zonal disintegration mechanism of isotropic rock masses around a deep circular tunnel subjected to dynamic unloading as well as the stress distributions. A constitutive model based on the GPD method is developed to simulate the zonal disintegration phenomenon in deep rock masses. The number and size of fractured and nonfractured zones are determined using the nonlinear unified strength criterion. It is shown from the numerical results that the dynamic loads and high in situ stress are two dominant factors for the occurrence of zonal disintegration.

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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