scholarly journals Rock strength criterion considering the effect of hydrostatic stress on lode angle effect

2019 ◽  
Vol 7 (4) ◽  
pp. 1166-1177
Author(s):  
Zhenlong Song ◽  
Minghui Li ◽  
Guangzhi Yin ◽  
Pathegama Gamage Ranjith ◽  
Chao Liu
Keyword(s):  
Rock Strength ◽  
Hydrostatic Stress ◽  
Strength Criterion ◽  
Angle Effect ◽  
Lode Angle ◽  
Rock Strength Criterion

scholarly journals Constitutive Model of Rock Uniaxial Damage Based on Rock Strength Statistics

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Ming Ji ◽  
Kai Chen ◽  
Hong Jun Guo
Keyword(s):  
Constitutive Model ◽  
Rock Strength ◽  
Strength Criterion ◽  
Uniaxial Stress ◽  
Evolution Process ◽  
Growth Stages ◽  
Numerical Fitting ◽  
Damage Constitutive Model ◽  
Log Normal

Based on the assumption that rock strength follows the log normal distribution statistically, this paper establishes a damage constitutive model of rock under uniaxial stress conditions in combination with the Mohr–Coulomb strength criterion and damage mechanical theory. Experiments were carried out to investigate the damage evolution process of rock material, which can be categorized into nondamaging, accelerated growth, constant-speed, similar growth, and speed-reducing growth stages. The evolution process had a good corresponding relationship with the rock stress-strain curves. Based on the statistical damage constitutive model proposed in this paper, a numerical fitting analysis was conducted on the uniaxial compression testing data of laboratory sand rock and on experimental data from other literature, in order to validate the rationality of the constitutive equation and the determination of its parameters and to analyze the effect of internal friction variables on damage variables and compression strength. The research outcomes presented in this paper can provide useful reference for the theory of rock mechanics and for rock engineering.

scholarly journals Three-Dimensional Numerical Analysis of the Tunnel for Polyaxial State of Stress

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Wenge Qiu ◽  
Chao Kong ◽  
Kai Liu
Keyword(s):  
Numerical Simulation ◽  
Mechanical Behavior ◽  
Principal Stress ◽  
Failure Criterion ◽  
Rock Strength ◽  
Strength Criterion ◽  
Intermediate Principal Stress ◽  
State Of Stress ◽  
Coulomb Failure ◽  
Coulomb Failure Criterion

The aim of this study is to have a comprehensive understanding of the mechanical behavior of rock masses around excavation under different value of intermediate principal stress. Numerical simulation was performed to investigate the influence of intermediate principal stress using a new polyaxial strength criterion which takes polyaxial state of stress into account. In order to equivalently substitute polyaxial failure criterion with Mohr-Coulomb failure criterion, a mathematical relationship was established between these two failure criteria. The influence of intermediate principal stress had been analyzed when Mohr-Coulomb strength criterion and polyaxial strength criterion were applied in the numerical simulation, respectively. Results indicate that intermediate principal stress has great influence on the mechanical behavior of rock masses; rock strength enhanced by intermediate principal stress is significant based on polyaxial strength criterion; the results of numerical simulation under Mohr-Coulomb failure criterion show that it does not exert a significant influence on rock strength. Results also indicate that when intermediate principal stress is relatively small, polyaxial strength criterion is not applicable.

Unification of Hoek-Brown Criterion on the Basis of United Strength Theory

2014 ◽  
Vol 501-504 ◽  
pp. 415-418
Author(s):  
Yuan Li ◽  
Qi Liang Liu ◽  
Qing Chi Cai
Keyword(s):  
Rock Mass ◽  
Rock Strength ◽  
Hard Rock ◽  
Strength Criterion ◽  
Strength Reduction ◽  
Strength Theory ◽  
Unified Strength Theory ◽  
Rock Mass Strength ◽  
Decomposition Formula ◽  
Theory Formula

Based on twin failure mechanism of fracture and shear , the bilinear transitional strength decomposition formula reflecting the nonlinear strength of rock material is proposed,.The decomposed brittle shear formula is integrated and finally the unified strength theory formula characterized by nonlinearity of Hoek-Brown criterion is established. It makes the unified strength theory characterized by nonlinearity of empirical strength criterion, rock mass strength reduction, etc. Besides, it contributes to promote the accuracy and applicability of unified strength theory in rock strength and rock mass strength,especially for the hard rock failure analysis.

A strength criterion for frozen clay considering the influence of stress Lode angle

2019 ◽  
Vol 56 (11) ◽  
pp. 1557-1572 ◽  
Author(s):  
Dun Chen ◽  
Dayan Wang ◽  
Wei Ma ◽  
Lele Lei ◽  
Guoyu Li
Keyword(s):  
Principal Stress ◽  
Three Dimensional ◽  
Strength Criterion ◽  
Frozen Soil ◽  
Principal Stress Space ◽  
The Mean ◽  
Frozen Clay ◽  
Lode Angle ◽  
Strength Functions ◽  
Elliptical Function

To investigate the influence of stress Lode angle on frozen soil, a series of directional shear tests was conducted on artificial frozen clay at three temperatures (–6, –10, and –15 °C) and five stress Lode angles (θσ = –30°, –16.1°, 0°, 16.1°, and 30°) using a hollow cylindrical apparatus. An elliptical function was proposed according to the strength envelope evaluation with the mean principal stress (p) in the p–q plane. In addition, generalized nonlinear strength theory (GNST) was introduced in the π plane to describe the evolution of the strength envelope with increasing mean principal stress. Then a strength criterion for frozen clay in three-dimensional principal stress space was proposed by combining strength functions in the p–q and π planes. The temperature effect was also introduced into the strength criterion. The proposed strength criterion can predict the multi-axial strength characteristics of frozen clay and reveal the influence of the stress Lode angle.

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