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.

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.

scholarly journals A Creep Damage Constitutive Model for a Rock Mass with Nonpersistent Joints under Uniaxial Compression

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Shuran Lv ◽  
Wanqing Wang ◽  
Hongyan Liu
Keyword(s):  
Rock Mass ◽  
Constitutive Model ◽  
Mechanical Behavior ◽  
Uniaxial Compression ◽  
Damage Model ◽  
Creep Damage ◽  
Model Parameters ◽  
Damage Constitutive Model ◽  
Set Up ◽  
Creep Damage Model

As part of the rock mass, both the mesoscopic and macroscopic flaws will affect the creep mechanical behavior of the rock mass with nonpersistent joints. This study focuses on this kind of rock mass and establishes a creep damage model to account for the effect of the joint on its creep mechanical behavior. First, on basis of analyzing the rock element creep mechanism and the typical creep deformation curve, a new creep damage constitutive model for the rock element is set up by introducing the damage theory and Kachanov damage evolution law into the classic creep constitutive model such as J body model. Second, the determination method of the proposed model parameters is studied in detail. Third, the calculation method of the macroscopic damage caused by the joint proposed by others is introduced which can consider the joint geometry, strength, and deformation parameters at the same time. Finally, the creep damage model for the rock mass with nonpersistent joints under uniaxial compression is proposed. The calculation examples indicate that it can present the effect of the joint on the rock mass creep mechanical behavior.

An elasto-plastic damage constitutive model for jointed rock mass with an application

2016 ◽  
Vol 11 (1) ◽  
pp. 77-94 ◽  
Author(s):  
Hanpeng Wang ◽  
Yong Li ◽  
Shucai Li ◽  
Qingsong Zhang ◽  
Jian Liu
Keyword(s):  
Rock Mass ◽  
Constitutive Model ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Plastic Damage ◽  
Damage Constitutive Model

Griffith’s Strength Loci for Jointed Rock Masses

1989 ◽  
Vol 111 (4) ◽  
pp. 270-278
Author(s):  
B. A. Chappell
Keyword(s):  
Rock Mass ◽  
Equilibrium Model ◽  
Failure Modes ◽  
Shear Failure ◽  
Soft Rock ◽  
Jointed Rock ◽  
Rock Masses ◽  
Loaded Rock ◽  
Deformation Models ◽  
Composite Moduli

Stress distribution in a rock material containing cracks, without thickness, and joints, with thickness, is controlled by two basic principles, namely equilibrium and compatibility. Two deformation models representing these two basic requirements are used to construct the rock mass’ local composite moduli that are then combined to obtain the rock mass’ global moduli. Deformational modes in the form of compliances give upper and lower value moduli representing the constraints of compatibility and equilibrium, respectively. In a loaded rock mass there is no stress redistribution involved in the application of the equilibrium model, while for the compatibility model there are stress redistributions. For cracks, with no thickness, only the equilibrium model defines the deformation moduli, whereas for joints both the equilibrium and compatibility models are required because of the joint’s volume effects. Using both the joint’s shear strength and the Griffith’s crack initiation criteria, the Griffith’s strength loci for firm-hard and soft rock masses are produced. The strength loci representing normal and shear failure modes for the firm-hard rock mass are significantly different, whereas for the soft rock mass they are similar.

Study on Failure of Rock Mass around Deep Tunnel

2011 ◽  
Vol 99-100 ◽  
pp. 370-374 ◽  
Author(s):  
Yue Hong Qian ◽  
Ting Ting Cheng ◽  
Xiang Ming Cao ◽  
Chun Ming Song
Keyword(s):  
Rock Mass ◽  
Stress Field ◽  
Failure Modes ◽  
Shear Failure ◽  
Simple Function ◽  
Tensile Failure ◽  
Deep Tunnel ◽  
Main Mode

During excavating the problem of unloading is a dynamic one essentially. Assuming the unloading ruled by a simple function and based on the Hamilton principal, the distribution of the stress field nearby the tunnel is obtained. The characteristics of the failure nearby the tunnel are analyzed considering the shear failure and tensile failure. The results show that the main mode of the shear failure, intact and tensile failure occurs from the tunnel. The characteristic of the shear failure, intact and tensile failure are one of the likely failure modes.

A statistical damage constitutive model considering whole joint shear deformation

2020 ◽  
Vol 29 (6) ◽  
pp. 988-1008 ◽  
Author(s):  
Shijie Xie ◽  
Hang Lin ◽  
Yixian Wang ◽  
Yifan Chen ◽  
Wei Xiong ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Damage Evolution ◽  
Shear Stiffness ◽  
Rock Joints ◽  
Residual Phase ◽  
Proposed Model ◽  
Damage Constitutive Model ◽  
Damage Theory ◽  
Joint Shear ◽  
Statistical Damage

The whole shear deformation of rock joints significantly affects the long-term behavior and safety of engineering projects. In this paper, a new damage constitutive model related to the Weibull distribution and statistical damage theory is proposed. This model considers the shear stiffness degradation, post-peak softening, and residual phase of rock joints in the whole shearing process. Main works include the three following aspects: First, the phase of initial damage is determined on the assumption that the joint shear failure is regarded as a result of damage evolution, according to the typical joint shear curve and the three-parameter Weibull distribution. Then, a statistical damage evolution model for the whole joint shearing process is introduced to make this model be capable of describing the residual phase of rock joints. Finally, a statistical constitutive model for the whole joint shearing process is proposed by statistical damage theory, and the calculated results of the models are compared to the experimental results. The results indicate that the proposed model shows a good agreement with the experimental examples, and the proposed model can distinctly reflect the effects of residual stress, peak stress, and shear stiffness. In addition, the model parameters can be mathematically confirmed and have distinct physical meanings.

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
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