Numerical Simulation of the Crack Propagation Processes in Rocks with Double Joints

2011 ◽  
Vol 90-93 ◽  
pp. 559-564 ◽  
Author(s):  
Jin Wei Fu ◽  
Wei Shen Zhu ◽  
Li Ge Wang ◽  
Xiang Gang Wang
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Crack Initiation ◽  
Rock Specimen ◽  
Failure Process ◽  
Jointed Rock ◽  
Two Dimensional ◽  
Analysis Software ◽  
Strength And Stiffness ◽  
The Stability

Engineering rock mass is commonly a brittle medium containing lots of joints or fissures. Under the stress redistribution in construction，the crack initiation，propagation，and coalescence may cause the strength and stiffness degradation of such medium. And these have an important impact on the stability of rock mass. By employing the analysis software of FLAC3D and improving the constitutive relation, the failure process of the double-cracked rock specimen under uniaxial and two-dimensional compression are simulated and studied. The numerical results match well with the testing results obtained by former scholars. The strength envelope of the jointed rock is obtained as well, and it is applied to analyzing the stability of a slope project.

scholarly journals Crack Initiation, Propagation, and Failure Characteristics of Jointed Rock or Rock-Like Specimens: A Review

2019 ◽  
Vol 2019 ◽  
pp. 1-31 ◽  
Author(s):  
Ri-hong Cao ◽  
Ping Cao ◽  
Hang Lin ◽  
Xiang Fan ◽  
Chunyang Zhang ◽  
...  
Keyword(s):  
Rock Mass ◽  
Crack Initiation ◽  
Failure Modes ◽  
Failure Process ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Failure Behavior ◽  
Failure Characteristics ◽  
Deformation And Failure ◽  
Natural Rock

Rock masses are heterogeneous materials containing a large number of discontinuities, and the failure of the natural rock mass is induced by the crack propagation and coalescence of discontinuities, especially for the rock mass around tunnel or underground space. Because the deformation or failure process of jointed rock mass exhibits strongly nonlinear characteristics, it is also very difficult to predict the strength and failure modes of the rock mass. Therefore, it is very necessary to study the failure mechanisms of jointed rock mass under different stress conditions. Apart from the stress condition, the discontinuities geometry also has a significant influence on the mechanical behavior of jointed rock mass. Then, substantial, experimental, and numerical efforts have been devoted to the study of crack initiation, propagation, and coalescence of rock or rock-like specimens containing different kinds of joints or fissures. The purpose of this review is to discuss the development and the contribution of the experiment test and numerical simulation in failure behavior of jointed rock or rock-like specimens. Overall, this review can be classified into three parts. It begins by briefly explaining the significance of studying these topics. Afterwards, the experimental and numerical studies on the strength, deformation, and failure characteristics of jointed rock or rock-like materials are carried out and discussed.

A Constitutive Model of Anchored Jointed Rock Mass and its Application

2008 ◽  
Vol 33-37 ◽  
pp. 657-662
Author(s):  
Xiao Jing Li ◽  
Wei Min Yang ◽  
Wei Shen Zhu ◽  
Shu Cai Li ◽  
Ai Hua Sun
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Constitutive Model ◽  
Damage Mechanics ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
The Stability ◽  
Effective Reinforcement ◽  
Macroscopic Failure ◽  
Damage Equation

The jointed rock mass distributed in the nature widely and its mechanical characteristic influenced the stability of the rock engineering badly. The cracks propagated and coalesced each other and macroscopic failure happened. Bolts were a kind of effective reinforcement instrument and they could prevent the cracks from propagating. However, the anchoring mechanism of bolts was not realized clearly and their reinforcement could not be reflected effectively in the numerical simulation yet. Based on the damage mechanics, a constitutive relation and damage equation of anchored jointed rock mass were presented in this paper. With a project application, the model was proved to be feasible one.

Crack Propagation of Jointed Rock and Application

2011 ◽  
Vol 117-119 ◽  
pp. 476-479
Author(s):  
Jing Wang ◽  
Wei Shen Zhu ◽  
Hai Ping Ma
Keyword(s):  
Mechanical Properties ◽  
Rock Mass ◽  
Crack Initiation ◽  
Crack Propagation ◽  
Failure Process ◽  
Jointed Rock ◽  
Rock Masses ◽  
Stress Strain ◽  
Jointed Rock Masses

Brittle media, such as rock mass, usually contain a great number of joints or cracks, which lead to varying mechanical properties and failure behaviors of different rock masses. In this paper, the DDARF method is adopted to simulate the crack initiation, propagation, coalescence and failure process in rock masses prefabricated with the different crack number and spacing under loading. The corresponding stress-strain curves and strength envelope are obtained. The parameters are applied in a case study. The differences in the failure behaviors of the intact and jointed rock masses after cavern excavation are analyzed and compared.

Application of ABAQUS in Surrounding Rock Stability Analysis of Shallow Large Cross-Section Tunnel

2015 ◽  
Vol 777 ◽  
pp. 8-12 ◽  
Author(s):  
Lin Zhen Cai ◽  
Cheng Liang Zhang
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Strong Support ◽  
Surrounding Rock ◽  
Tunnel Engineering ◽  
Tunnel Excavation ◽  
Rock Stability ◽  
Rock Bolting ◽  
Excavation Support ◽  
The Stability

HuJiaDi tunnel construction of Dai Gong highway is troublesome, the surrounding-rock mass give priority to full to strong weathering basalt, surrounding rock integrity is poor, weak self-stability of surrounding rock, and tunnel is prone to collapse. In order to reduce disturbance, taking advantage of the ability of rock mass, excavation adopt the method of "more steps, short footage and strong support". The excavation method using three steps excavation, The excavation footage is about 1.2 ~ 1.5 m; The surrounding rock bolting system still produce a large deformation after completion of the first support construction, it shows that the adopted support intensity cannot guarantee the stability of the tunnel engineering. Using ABAQUS to simulate tunnel excavation support, optimizing the support parameters of the tunnel, conducting comparative analysis with Monitoring and Measuring and numerical simulation results, it shows that the displacement - time curves have a certain consistency in numerical simulation of ABAQUS and Monitoring and Measuring.

Model Testing and Analysis Study on Shear Strength of Rock Mass Containing Multiple Cracks under Compression-Shearing Loading

2008 ◽  
Vol 33-37 ◽  
pp. 617-622
Author(s):  
Wei Shen Zhu ◽  
Bin Sui ◽  
Wen Tao Wang ◽  
Shu Cai Li
Keyword(s):  
Shear Strength ◽  
Rock Mass ◽  
Rock Sample ◽  
Failure Process ◽  
Jointed Rock ◽  
Multiple Cracks ◽  
Test Results ◽  
Failure Model ◽  
Two Phase ◽  
Bridge Failure

Two-phase modelling testing was performed to study the shear strength of rock bridges of jointed rock mass in this paper. The failure process of rock sample containing multiple collinear cracks was observed. Based on theory of fracture mechanics and analytical method, a rock-bridge failure model was proposed and the expression of shear strength was derived. Comparison of calculated shear strength and the model test results was made and they agree well.

scholarly journals Coupling Effect of Creep Deformation and Prestress Loss of Anchored Jointed Rock

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Bairu Zhu ◽  
Yang Song ◽  
Heping Wang ◽  
Yongqi Li
Keyword(s):  
Rock Mass ◽  
Stress Level ◽  
Coupling Effect ◽  
Jointed Rock ◽  
In Situ Stress ◽  
Calculation Model ◽  
Prestress Loss ◽  
Stress States ◽  
The Stability ◽  
Anchor Design

To explore the variation behaviour of anchor jointed rock subject to high in situ stress states, a coupling effect calculation model based on stress equality was established based on the original rheological model of rock by combining element combination theory and experiment, and the model was verified. The coupling effect between rock mass creep and bolt prestress loss is established by setting the deterioration function of bolt prestress loss. The uniaxial creep test is performed on specimens with different joint angles, and the results show that the prestress loss time in anchor rods decreases linearly with increasing stress level. With increasing stress level, the time of prestress loss decreases linearly with the increase in stress level. With increasing axial load, the deformation caused by the transverse expansion stress of the specimen can offset the compression deformation of the prestressed anchor rod. The relationship between prestress loss in anchors and creep of rock is solved theoretically, and the stability criterion for anchor jointed rock is proposed. The results of this study provide a scientific reference for anchor design of deep jointed rock mass.

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