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.

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.

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.

A Nonlinear Constitutive Model for Soil under Complex Stress State

2013 ◽  
Vol 535-536 ◽  
pp. 561-564 ◽  
Author(s):  
Hang Zhou Li ◽  
Hong Jian Liao ◽  
Bo Han ◽  
Li Song
Keyword(s):  
Constitutive Model ◽  
Principal Stress ◽  
Friction Angle ◽  
Complex Stress ◽  
Complex Stress State ◽  
Intermediate Principal Stress ◽  
Strength Theory ◽  
Unified Strength Theory ◽  
Strain Behavior ◽  
Chang Model

It is fundamental to predict the stress-strain behavior of soils to control the stability of the geotechnical engineering. A Duncan-Chang constitutive model is analyzed and found that it ignores the effect of the intermediate principal stress. A unified strength theory is investigated and revised. The lode parameter is introduced into the unified strength theory. The unified friction angle and cohesion which may reflect the influence of the intermediate principal stress and verified by the polyaxial tests are obtained. The compressive strength revised from the unified strength theory is used to replace the Mohr-Coulomb criterion and introduced into the Duncan-Chang model. A modified constitutive model is proposed, which is verified by the plane strain tests. The result shows that the modified constitutive can reflect the effect of the intermediate principal stress, and the Duncan-Chang model is a special case of the modified model when b=0.

Influence of Intermediate Principal Stress Effect on Flat Punch Problems

2013 ◽  
Vol 535-536 ◽  
pp. 300-305
Author(s):  
Zong Yuan Ma ◽  
Hong Jian Liao ◽  
Fa Ning Dang
Keyword(s):  
Principal Stress ◽  
Three Dimensional ◽  
Intermediate Principal Stress ◽  
Stress Effect ◽  
Strength Theory ◽  
Lagrangian Analysis ◽  
Flat Punch ◽  
Unified Strength Theory ◽  
Intermediate Principal Stress Effect ◽  
Punch Problem

Using the finite difference code FLAC3D (Fast Lagrangian Analysis of Continua in 3 Dimensions) and UST (Unified Strength Theory), the influence of the intermediate principal stress effect on the problems of flat punch are analyzed in this paper. The values of the ultimate bearing capacity resulting from numerical analyses and the analytical solution of Prandtl’s strip punch problem are compared. The three-dimensional problems of strip, rectangular, square and circular punches on a semi infinite metallic medium have been analyzed.

Analysis of Small Non-Sand Concrete Pile Grouting Pressure Based on Unified Strength Theory

2012 ◽  
Vol 166-169 ◽  
pp. 3095-3099
Author(s):  
Huai Feng Tong
Keyword(s):  
Stress State ◽  
Principal Stress ◽  
Limit State ◽  
Intermediate Principal Stress ◽  
Plastic State ◽  
Strength Theory ◽  
Unified Strength Theory ◽  
Grouting Pressure ◽  
Concrete Pile ◽  
The Relationship

Analysis of stress state of soil around the pile and grouting pressure of small non-sand concrete pile is given based on the expansion elastic theory of cylindrical cavity and the unified strength theory, the grouting pressure formula is obtained in the elastic limit state and elastic-plastic state of soil around the pile considered the intermediate principal stress, and the relationship is obtained between the grouting pressure and the plastic radius; When the soil around the pile is in different stress state, the correlativity of crack and densification of grouting is analyzed, and the relationship between the grouting pressure and the plastic radius is discussed with the right coefficient of the intermediate principal stress and initial press under different values. The obtained results have provided efficient analysis means for grouting optimal design of post-processing technology with small non-sand concrete pile.

The Development and Implementation of Improved Duncan-Chang Constitutive Model in ABAQUS

2011 ◽  
Vol 99-100 ◽  
pp. 965-971
Author(s):  
Zhi Ping Dai ◽  
Cheng Zhao ◽  
Chun Feng Zhao
Keyword(s):  
Constitutive Model ◽  
Principal Stress ◽  
Deformation Behavior ◽  
Fine Sand ◽  
Intermediate Principal Stress ◽  
Strength Theory ◽  
Unified Strength Theory ◽  
Dense Sand ◽  
Improved Model ◽  
Chang Model

As it ignorance the effect of intermediate principal stress, traditional Duncan - Chang model has limitation when applied into geotechnical engineering. It was improved through incorporating the effect of intermediate principal stress based on unified strength theory. Under the help of customized modification platform in ABAQUS, the applicability and stability of the improved model and the reliability of subroutine were validated through simulation of several examples. The results show the improved model can better reflect the deformation behavior of soil through taking the influence of intermediate principal stress into consideration. The improved model in paper can be applied into dense sand, fine sand and clay.

Slope Stability Analysis Using Unified Strength Theory

2011 ◽  
Vol 137 ◽  
pp. 59-64
Author(s):  
Zong Yuan Ma ◽  
Hong Jian Liao ◽  
Mao Hong Yu
Keyword(s):  
Slope Stability ◽  
Plane Strain ◽  
Principal Stress ◽  
Stability Problem ◽  
Factor Of Safety ◽  
Intermediate Principal Stress ◽  
Flow Rule ◽  
Problem Analysis ◽  
Strength Theory ◽  
Unified Strength Theory

Numerical computations using finite difference method and unified strength theory are reported to analyze the slope stability problem. The Factor of safety of plane strain and axisymmetric slopes was calculated by strength reducing method, and the influences of intermediate principal stress on slope stability problem was analyzed. The associative and non-associative flow rule was taking into account in plane strain slope problem analysis. The intermediate principal stress has equivalent influences on slope stability problem under associative and non-associative flow rule. The Factor of safety of plane strain slope is lower than the axisymmetric situation. The influence of intermediate principal stress on slope stability under plane strain condition is heavier than axisymmetry.

scholarly journals Mechanical Analysis of the Circular Tunnel considering the Interaction between the Ground Response Curve and Support Response Curve

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Tianming Su ◽  
Hanyu Peng ◽  
Hongyan Liu
Keyword(s):  
Plastic Zone ◽  
Radial Displacement ◽  
Response Curve ◽  
Mechanical Analysis ◽  
Surrounding Rock ◽  
Elastic Displacement ◽  
Circular Tunnel ◽  
Ground Response ◽  
Support Structure ◽  
Zone Radius

The viewpoint that the ground initial elastic displacement and the interaction between the ground response curve (GRC) and support response curve (SRC) in the surrounding rock should be considered at the same time in the mechanical analysis of the circular tunnel is proposed, and its solution method is also established. Meanwhile, in order to consider the effect of the intermediate principle stress, Drucker-Prager criterion is introduced to describe the yield property of the surrounding rock. The calculation example indicates that the final radial displacement of the tunnel circumference will increase when the ground initial elastic displacement in the surrounding rock is considered before the support structure is applied, which indicates that it is necessary to consider the ground initial elastic displacement in the surrounding rock before the support structure is applied. With increasing the support resistance force and the initial field stress, the plastic zone radius in the surrounding rock and the radial displacement of the tunnel circumference will decrease and increase, respectively, while with increasing the rock internal friction angle and cohesion, the plastic zone radius in the surrounding rock and the radial displacement of the tunnel circumference both decrease. Meanwhile, with the stress Lode parameter increasing from −1 to 1, the plastic zone radius in the surrounding rock and the radial displacement of the tunnel circumference both greatly decrease and then slightly increase. It indicates that the intermediate principle stress has some effect on the calculation results.

Elastic–Brittle–Plastic Analysis of Double-Layered Combined Thick-Walled Cylinder Under Internal Pressure

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Qian Zhu ◽  
Junhai Zhao ◽  
Changguang Zhang ◽  
Yan Li ◽  
Su Wang
Keyword(s):  
Internal Pressure ◽  
Principal Stress ◽  
Yield Criterion ◽  
Engineering Application ◽  
Strength Criterion ◽  
Intermediate Principal Stress ◽  
Material Behavior ◽  
Strength Theory ◽  
Special Cases ◽  
Walled Cylinder

The elastic–brittle–plastic unified solutions of limit internal pressure are presented for double-layered combined thick-walled cylinder by the triple-shear unified strength criterion. The unified solutions obtained in this paper are especially versatile that can take into account of material brittle softening and intermediate principal stress quantitatively. The conventional existing elastic-perfectly plastic solutions, based on the Tresca yield criterion, Mises yield criterion, or twin-shear strength theory, can be categorized as special cases of the present unified solutions which can overcome their shortages. Parametric studies were carried out to evaluate the influences of various factors such as brittle softening parameter, strength theory parameter, cohesion, internal friction angle, and intermediate principal stress coefficient on the unified solutions. It is shown that proper choices of failure criterion, material behavior model, and brittle softening are significant in combined cylinder design. The new solutions can be naturally degraded to the existing formula and agree well with the results of the prevailing failure criteria. It is concluded that the unified solutions have an important practical value for the optimum design and engineering application of combined thick-walled cylinder.

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