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.

Finite Element Analysis of Dongjusi Railway Tunnel within Hard Rock Mass Based on the Unified Rock Mass Strength Criterion

2007 ◽  
Vol 353-358 ◽  
pp. 2994-2997
Author(s):  
Yuan Hua ◽  
Tai Quan Zhou ◽  
Guo Liang Dai
Keyword(s):  
Rock Mass ◽  
Principal Stress ◽  
Hard Rock ◽  
Plastic Material ◽  
Strength Criterion ◽  
Intermediate Principal Stress ◽  
Stress Effect ◽  
Railway Tunnel ◽  
Rock Mass Strength ◽  
Intermediate Principal Stress Effect

The twin shear strength criterion has been proposed to consider the intermediate principal stress effect on the rock mass strength. The unified rock mass strength criterion could consider the intermediate principal stress effect on the rock mass strength. The unified rock mass elasto-plastic material model is implemented in ABAQUS user interface. As a case for study, the stability analysis of Dongjusi railway tunnel within hard rock mass is studied using the unified rock mass strength material. For comparison, the Hoek-Brown empirical strength criterion is also chosen for the rock mass material modeling. The computation results show that the plastic zone calculated using the unified rock mass strength criterion is smaller than that using the Hoek-Brown empirical strength criterion. The railway tunnel lining structure is designed according to the unified rock mass strength criterion and greatly makes use of the rock mass potential strength, which decreases engineering cost.

Study on the Bearing Capacity of Slime Friction Pile Based on the Double-Sheared Theory

2013 ◽  
Vol 353-356 ◽  
pp. 1005-1010
Author(s):  
Xiang Qiu Wang ◽  
Wen Tao Yang
Keyword(s):  
Bearing Capacity ◽  
Strength Criterion ◽  
Intermediate Principal Stress ◽  
Resistance Force ◽  
Strength Theory ◽  
Unified Strength Theory ◽  
Friction Resistance ◽  
Double Shear ◽  
Friction Pile ◽  
Lateral Friction

The bearing capacity of slime friction pile based on the Mohr-Coulombs strength criterion couldnt make full use of the potential strengths ability of rock-soil. But the double shear unified strength theory can depict really the bearing characteristics of rock-soil because it can consider the effect of intermediate principal stress comprehensively. On this condition, based on the Mindlins displacement solution and the double shear unified strength theory, a calculated formula of bearing capacity was proposed for the slime friction pile, and then the distribution regularities of lateral friction-resistance force for the slime friction pile were discussed.

Analysis of Influences of Weak Joints and Confining Pressure on Rock Mass Strength by Numerical Simulation

2013 ◽  
Vol 438-439 ◽  
pp. 607-611 ◽  
Author(s):  
Da Hai Wang ◽  
Hao Ran Guo ◽  
Hui Zhao ◽  
Yan Wei Guo
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Plastic Zone ◽  
Influencing Factors ◽  
Rock Strength ◽  
Strain Softening ◽  
Confining Pressure ◽  
Plasticity Model ◽  
Rock Mass Strength

Principal influencing factors of the strength of rock mass with weak joints were studied in this paper. Dip angles of weak joints in addition with the confining pressure is studied based on strain-softening/hardening plasticity model. The broken mechanism from the perspective of plastic zone was analyzed. The strength of rock mass with weak joints is mainly under control of the joints occurrence, the joints dip and the rock strength, and great influenced by the confining pressure. A higher strength is obtained with a higher confining pressure, the broken mechanisms varies with different joints dips.

Rock Mass Strength Estimation Using Structural Factor Based on Statistical Strength Theory

2018 ◽  
Vol 277 ◽  
pp. 111-122 ◽  
Author(s):  
Dmytro Babets
Keyword(s):  
Rock Mass ◽  
Scale Effect ◽  
Structural Factor ◽  
Statistical Approach ◽  
Quantitative Estimation ◽  
Discontinuity Surface ◽  
Strength Theory ◽  
Support Design ◽  
Statistical Strength ◽  
Rock Mass Strength

Quantitative estimation of scale effect is a complex problem which contained many uncertainties and should be solved using probability calculus and statistical approach. This paper aims to derive the structural factor according statistical strength theory involving discontinuity surface conditions account to estimate the design rock mass strength. A short review of scale effect estimation techniques based on statistical strength theory is given. A new method of structural factor evaluation is proposed. This technique allows accounting discontinuity conditions by changing the variation of tested specimen random sample. A function that describes the decreasing of strength due to poor discontinuity surface quality is introduced to correct the initial and central statistical moments of strength random distribution. The evaluation of the joints condition function based on analysis of the results of uniaxial compressive strength tests and petrographic structure of specimens is shown. Improving the statistical approach of structural factor evaluating increase the accuracy of the rock mass strength assessment and allow avoiding costly modifications of the mining excavation support design. A case of rock mass strength estimation under conditions of coal mine “Komsomolets Donbassa” according to proposed statistical method is studied.

New strength formulae for rock surrounding a circular opening

2013 ◽  
Vol 50 (7) ◽  
pp. 735-743 ◽  
Author(s):  
Wen Fan ◽  
Mao-hong Yu ◽  
Long-sheng Deng ◽  
Xianglin Peng ◽  
Li-wei Chen
Keyword(s):  
Plastic Material ◽  
Strength Criterion ◽  
Surrounding Rock ◽  
Strength Theory ◽  
Unified Strength Theory ◽  
Special Cases ◽  
Elastic Plastic Material ◽  
Strength Models ◽  
Strength Formula ◽  
Strain Model

In this paper, the unified strength theory proposed by Yu Mao-hong in 1991 is used to develop new strength formulae for rock surrounding a tunnel. The new formulae can be applied to an elastic–plastic material. The formulae have a series of expressions with the unified parameter, especially variations such as the well-known Kastner and Airy formulae, which are widely used in rock mechanics and engineering. These formulae are derived on the basis of the Mohr–Coulomb strength criterion. For the strength-weakening (plastic-softening) of geomaterials, the analytical solutions for the radius of the plastic residual zones, radius of the plastic-softening zones, and displacement around the opening are presented according to the elastoplastic-softening – residual plastic, tri-linear stress–strain model. In addition, the derivation for the stress state in the surrounding rock is given. The Kastner formula, Airy formula, and available solutions can be considered as special cases in the new strength formula. The influence of softening, shear dilatancy, and different strength models on the results is analyzed. The results presented in this paper are useful for analyzing surrounding rock with various stress conditions and reinforcement of caves.

scholarly journals The Plastic Zone of Tunnel Surrounding Rock under Unequal Stress in Two Directions Based on the Unified Strength Theory

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zongshan Zou ◽  
Jun Yang ◽  
Zhongming Wang ◽  
Hongyan Liu
Keyword(s):  
Plastic Zone ◽  
Principal Stress ◽  
Interaction Mechanism ◽  
Strength Criterion ◽  
Intermediate Principal Stress ◽  
Surrounding Rock ◽  
Elastic Displacement ◽  
Strength Theory ◽  
Support Structure ◽  
Unified Strength Theory

For the deficiencies that the existing calculation theory for the Plastic Zone of Tunnel Surrounding Rock (PZTSR) does not consider the effect of the intermediate principal stress σ2 and interaction between the surrounding rock and support structure on the PZTSR under unequal stress, the Unified Strength Theory (UST) for the rock is adopted to replace the often used Mohr-Coulomb (M-C) strength criterion to consider the effect of σ2 on the PZTSR. Meanwhile, the interaction mechanism between the surrounding rock and support structure is also considered in the proposed model. Finally, the effect of the initial elastic displacement of the surrounding rock, stiffness of the support structure, and the coefficient b of the intermediate principal stress on the plastic zone is discussed. The results show that the PZTSR will increase nonlinearly with increasing the initial elastic displacement of the surrounding rock, and when it increases to a certain value, its increase extent will be much obvious. With increasing the stiffness of the support structure, the PZTSR will gradually decrease nonlinearly, but the decrease extent is not very much. With increasing b, the PZTSR will decrease; namely, σ2 can improve the stress condition of the surrounding rock and reduce the PZTSR.

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