scholarly journals A Compressive Damage Constitutive Model for Rock Mass with a Set of Nonpersistently Closed Joints under Biaxial Conditions

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Hongyan Liu ◽  
Xiaoping Yuan
Keyword(s):  
Mechanical Property ◽  
Rock Mass ◽  
Mechanical Behavior ◽  
Confining Pressure ◽  
Jointed Rock ◽  
Theoretical Evaluation ◽  
Rock Mass Strength ◽  
Proposed Model ◽  
Damage Constitutive Model ◽  
Satisfactory Answer

One of the most problems faced by the practical rock engineering is to evaluate the rock mass strength. Now the existing theoretical evaluation of the mechanical property of jointed rock mass has no satisfactory answer yet because of the great number of variables involved. One of them is the nonpersistent joints which inherently affect the rock mass mechanical behavior. The previous models for rock mass can only reflect the effect of joint geometrical property on its mechanical behavior. Accordingly, this paper presents a new theoretical model to evaluate the mechanical behavior of the rock mass with a set of nonpersistently closed joints under biaxial conditions, which can reflect the effect of both the joint geometrical and mechanical property on the mechanical behavior of the rock mass under biaxial conditions at the same time. A series of calculation examples validate that the proposed model is capable of presenting the effect of joint geometrical and mechanical properties and the confining pressure on rock mass strength at the same time.

A damage constitutive model for rock mass with persistent joints considering joint shear strength

2015 ◽  
Vol 52 (8) ◽  
pp. 1136-1143 ◽  
Author(s):  
Hongyan Liu ◽  
Xiaoping Yuan
Keyword(s):  
Rock Mass ◽  
Constitutive Model ◽  
Failure Modes ◽  
Shear Failure ◽  
Jointed Rock ◽  
Joint Shear Strength ◽  
Rock Mass Strength ◽  
Damage Constitutive Model ◽  
Joint Shear ◽  
Set Up

Microcracks and joints, two types of flaws that appear in a rock mass, affect both the rock mass strength and deformability. A model that can simultaneously reflect the effect of these two types of flaws on the mechanical behavior of a rock mass with persistent joints is not yet available. This study focusses on a microcracked rock mass with persistent joints and establishes a mechanical model, accounting for the anisotropy in the rock mass strength and deformability induced by the existence of the joints. Firstly, the compound damage variable from the coupling macroscopic and mesoscopic flaws is deduced based on the Lemaitre strain equivalence hypothesis. Secondly, the corresponding damage constitutive model for a jointed rock mass is set up. Thirdly, the joint shear failure criterion is incorporated into the constitutive model to extend the model. Finally, the results of the calculation examples show that the existence of the joint will reduce the strength, enlarge the deformability, and lead to anisotropy of the rock mass. A series of calculation examples and comparisons validate that the proposed model is capable of presenting the joint-induced anisotropy in rock mass strength and deformability, determining its possible failure modes, and reasonably simulating its complete stress–strain relationship.

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.

A numerical method for modelling large displacements of jointed rocks. I. Fundamentals

1993 ◽  
Vol 30 (1) ◽  
pp. 96-108 ◽  
Author(s):  
Baolin Wang ◽  
Vinod K. Garga
Keyword(s):  
Rock Mass ◽  
Numerical Method ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Contact Forces ◽  
Deformation Analysis ◽  
Large Displacements ◽  
Equilibrium Equations ◽  
Proposed Model ◽  
Jointed Rocks

A numerical method called the block-spring model for analyzing heavily jointed rocks is presented in this paper. This model permits the assessment of stability of both underground and surface excavation in jointed rock mass and is capable of simulating large displacements. The model simulates the jointed rock mass by an assemblage of rigid blocks interacting through contacts. By relating the contact forces to the relative displacements between the blocks and directly applying the equilibrium equations, the displacements of the blocks and subsequently the contact forces can be determined. An iteration procedure is applied to describe the progressive failure along the joints. The proposed model can identify unstable blocks by considering the rearrangement of the blocks. A computer program has been written in FORTRAN based on the procedures of the proposed model. Some simple examples are presented in the present paper to demonstrate the capability of the proposed model. Advanced features of the model including simulation of rock bolts and groundwater are presented in a companion paper, in which two case histories have been analyzed in detail with the proposed model. Key words : jointed rocks, stress, deformation, analysis, numerical model, excavation, anchors, groundwater.

Anisotropic Nature of Jointed Rock Mass Strength

1989 ◽  
Vol 115 (3) ◽  
pp. 525-542 ◽  
Author(s):  
Bernard Amadei ◽  
William Z. Savage
Keyword(s):  
Rock Mass ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Rock Mass Strength

Mechanical behavior of structurally reconstructed irregular columnar jointed rock mass using 3D printing

2020 ◽  
Vol 268 ◽  
pp. 105509 ◽  
Author(s):  
Yingjie Xia ◽  
Chuanqing Zhang ◽  
Hui Zhou ◽  
Jing Hou ◽  
Guoshao Su ◽  
...  
Keyword(s):  
Rock Mass ◽  
3D Printing ◽  
Mechanical Behavior ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Columnar Jointed Rock Mass

scholarly journals Study of Shear Capacity of Jointed Rock Mass with Prestressed Anchor Bolt

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Yufei Zhao ◽  
Hongtao Zhang ◽  
Yong Nie
Keyword(s):  
Mechanical Property ◽  
Rock Mass ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Shear Capacity ◽  
Anchor Bolt ◽  
Engineering Research ◽  
Shearing Strength ◽  
Stress And Deformation ◽  
Prestressed Anchor

Rock mass failure caused by jointed plane is the common disaster in geotechnical engineering. Research on shearing property of jointed rock mass with prestressed anchor bolt and its mechanical property is an aspect for the stability analysis of rock slope and tunnel. This paper studies the stress and deformation of bolt and jointed plane, as well as anchored body and rock mass during shearing by indoor model testing and theoretical analysis. The shearing strength and mechanical property of anchored jointed plane have been systematically studied, and the additional force caused by deformation of prestressed anchor bolt and jointed rock mass during the shearing has been proposed and verified. The anchorage interaction between rock mass and bolt is revealed.

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