scholarly journals A Simple Three-Dimensional Failure Criterion for Jointed Rock Masses under True Triaxial Compression

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Yaohui Gao ◽  
Chunsheng Zhang ◽  
Zhaofeng Wang ◽  
Jun Chen
Keyword(s):  
Failure Criterion ◽  
Triaxial Compression ◽  
Three Dimensional ◽  
Friction Angle ◽  
Failure Criteria ◽  
Jointed Rock ◽  
Rock Masses ◽  
True Triaxial ◽  
Jointed Rock Masses ◽  
Triaxial Strength

The joint configuration and the intermediate principal stress have a significant influence on the strength of rock masses in underground engineering. A simple three-dimensional failure criterion is developed in this study to predict the true triaxial strength of jointed rock masses. The proposed failure criterion in the deviatoric and meridian planes adopts the elliptic and hyperbolic forms to approximate the Willam–Warnke and Mohr–Coulomb failure criterion, respectively. The four parameters in the proposed failure criterion have close relationships with the cohesion and the internal friction angle and can be linked with the joint inclination angle using a cosine function. Two suits of true triaxial strength data are collected to validate the correctness of the proposed failure criterion. Compared with other failure criteria, the proposed failure criterion is more reasonable and acceptable to describe the strength of jointed rock masses.

scholarly journals Primary Investigation on Equivalent Anchoring Method of Jointed Rock Mass Tunnel and Its Engineering Application

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Min Gao ◽  
Shanpo Jia
Keyword(s):  
Rock Mass ◽  
Three Dimensional ◽  
Engineering Application ◽  
Friction Angle ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Surrounding Rock ◽  
Rock Masses ◽  
Reinforcement Effect ◽  
Rock Bolts

Rock bolts, one of the main support structures of the tunnel, can improve the stress state and mechanical properties of the surrounding rocks. The rock bolts are simulated by bar or beam elements in present numerical calculations for most 2D tunnel models. However, the methods of simulating rock bolt in three-dimensional models are rarely studied. Moreover, there are too many rock bolts in the long-span tunnel, which are hardly applied in the 3D numerical model. Therefore, an equivalent anchoring method for bolted rock masses needs to be further investigated. First, the jointed material model is modified to simulate the anisotropic properties of surrounding rock masses. Then, based on the theoretical analysis of rock bolts in reinforcing mechanical properties of the surrounding rock masses, the equivalent anchoring method of the jointed rock mass tunnel is numerically studied. The equivalent anchoring method is applied to the stability analysis of a diversion tunnel in Western China. From the calculation results, it could be found that the reinforcement effect of rock bolts could be equivalently simulated by increasing the mechanical parameter value of surrounding rocks. For the jointed rock mass tunnel, the cohesion and internal friction angle of the surrounding rocks are improved as 1.7 times and 1.2 times of the initial value, which can simulate the reinforcement effect of rock bolts. Comparing with analytical results, the improved internal friction angle is nearly consistent with analytical result. The reinforcement effect of rock bolts is simulated obviously when the mechanical parameters of surrounding rocks are increased simultaneously. The engineering application shows that the equivalent anchoring method can reasonably simulate the effect of rock bolts, which can provide reference for stability analysis of three-dimensional tunnel simulations.

A Three-Dimensional Failure Criterion for Hard Rocks Under True Triaxial Compression

2019 ◽  
Vol 53 (1) ◽  
pp. 103-111 ◽  
Author(s):  
Xia-Ting Feng ◽  
Rui Kong ◽  
Chengxiang Yang ◽  
Xiwei Zhang ◽  
Zhaofeng Wang ◽  
...  
Keyword(s):  
Failure Criterion ◽  
Triaxial Compression ◽  
Three Dimensional ◽  
True Triaxial ◽  
Hard Rocks ◽  
True Triaxial Compression

scholarly journals Analysis of Changes in the Micromorphology of Sandstone Joint Surface under Dry-Wet Cycling

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Jingcheng Fang ◽  
Huafeng Deng ◽  
Yu Qi ◽  
Yao Xiao ◽  
Hengbin Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Friction Angle ◽  
Jointed Rock ◽  
Joint Surface ◽  
Roughness Coefficient ◽  
Rock Masses ◽  
Jointed Rock Masses ◽  
Bank Slope ◽  
Steep Decrease ◽  
The Face

Changes in the micromorphology of joint surface under dry-wet cycling have a direct effect on the mechanical properties of the jointed rock masses, which in turn affects the deformation stability of the bank slope of a reservoir. In this study, we design and carry out a test that aims to quantity the effects of repeated rise and fall of a reservoir on the properties of a jointed rock masses. The results are as follows: first, the roughness, local gradient, and undulation of the joint surface gradually decreased under repeated dry-wet cycling. In addition, the height parameters and texture parameters showed a steep decrease followed by a slow decline. The deterioration was particularly obvious over the first 5 dry-wet cycles. Second, the roughness coefficient of the joint surface, the compressive strength of the face wall, and the basic friction angle were gradually reduced under dry-wet cycling. The shear strength of the jointed rock masses (obtained both quantitatively and experimentally) showed a deteriorating trend controlled by the deterioration of the micromorphology, the strength of the face wall, and the frictional properties of the joint surface. Finally, the dry-wet cycling process determined trends of changes in the microstructure parameters and mechanical properties of the joint surface. Our research results provide a good basis for the analysis of the deterioration and failure of rock masses within the hydrofluctuation belt of a bank slope.

Triaxial Compression Experimental Study on Post-Peak Deformation Characteristics of Rock Masses with Persistent Joints

2014 ◽  
Vol 1030-1032 ◽  
pp. 1074-1077
Author(s):  
Yang Ping ◽  
Shu Chen Li
Keyword(s):  
Triaxial Compression ◽  
Jointed Rock ◽  
Peak Strain ◽  
Deformation Characteristics ◽  
Test Results ◽  
Rock Masses ◽  
Underground Excavations ◽  
Jointed Rock Masses ◽  
Confining Pressures ◽  
The Stability

Controlling the stability of surrounding rocks in underground excavations during in-depth resource development must be confronted with post-peak deformation and failure problems of jointed rock masses. This paper describes routine triaxial compression testing on standard cylinder specimen with persistent joints in different inclinations and under different confining pressures, and analyzes deformation characteristics of rock masses with persistent joints in different inclinations and under different confining pressures. Test results show that the peak strength, residual strength, and peak strain of the jointed specimen basically increase with increasing confining pressures but decrease with increasing joint inclinations. Test results well reflect that it is incorrect to evaluate deformation characteristics of jointed rock masses with continuum mechanics and research results provide a reference for the research on the stability of surrounding rocks in underground excavations.

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