Forecast Jointed Rock Mass Compressive Strength Using a Numerical Model

The generalized model is constructed for jointed rock mass under hydrodynamic pressure. Meanwhile, the influences of crack angle, under hydrodynamic pressure, on the compressive strength is researched. The results show that the flow rate has a significant influence on the compressive strength of jointed rock. When the angle of the crack is 30°, the higher the hydrodynamic pressure is, the larger the decrease of the compressive strength is. While the slopes of the crack are 45° and 60°, the larger the hydrodynamic pressure is, the bigger the increase of the compressive strength is. In the meantime, under the same flow rate, the compressive strength of jointed rock transform regularly with crack angle changed. And the compressive strength of the jointed rock with 45° crack is largest, while the jointed rock with 30° crack is lowest.

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Experimental Study and Numerical Simulation on the Compressive Strength Size Effect of Jointed Rock Mass

Proceedings of the 2010 International Conference on Mechanical, Industrial, and Manufacturing Technologies (MIMT 2010) ◽

10.1115/1.859544.paper56 ◽

2010 ◽

pp. 355-360

Author(s):

Dong-ping Li ◽

Jin-long Wei ◽

Qian-yuan Wang ◽

Jun Li

Keyword(s):

Numerical Simulation ◽

Experimental Study ◽

Compressive Strength ◽

Rock Mass ◽

Size Effect ◽

Jointed Rock ◽

Jointed Rock Mass

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Study on the Failure Mechanism for Coal Roadway Stability in Jointed Rock Mass Due to the Excavation Unloading Effect

Energies ◽

10.3390/en13102515 ◽

2020 ◽

Vol 13 (10) ◽

pp. 2515 ◽

Cited By ~ 3

Author(s):

Eryu Wang ◽

Guangbo Chen ◽

Xiaojie Yang ◽

Guofeng Zhang ◽

Wenbin Guo

Keyword(s):

Rock Mass ◽

Numerical Model ◽

Crack Propagation ◽

Failure Mechanism ◽

Jointed Rock ◽

Jointed Rock Mass ◽

Surrounding Rock ◽

Coal Roadway ◽

Roadway Stability ◽

Rock Structure

Aiming at the large deformation instability problem caused by the excavation unloading of a coal roadway in deep-buried slowly inclined jointed rock mass, the geomechanical parameters and deformation failure characteristics of an engineering geomechanical model were investigated. The in-situ stress state of the model was measured with the stress relief method. The geological and mechanical properties of roadway surrounding rock were described. The surrounding rock structure was revealed with the electron microscopy scanning method, micro-fractures and randomly distributed joints highly developed in roadway surrounding rock. Field investigation and monitoring indicated the cross-section of roadway surrounding rock shrank continuously and the deformation distribution was obviously asymmetric. Shotcrete spalling and cable broken failures frequently occurred in the middle and ride side of roof and right rib. Based on the geomechanical conditions of the coal roadway, a discrete element numerical model of coal roadway in gently inclined jointed rock mass was established. The parameters of rock mass in the numerical model were calibrated. The model ran in unsupported condition to restore the evolution process of stress, crack propagation and deformation in roadway surrounding rock due to gradual deviatoric stress release caused by excavation. On this basis, the space-time evolution characteristics and law of stress, crack propagation and deformation were obtained and then the asymmetric large fragmentation and dilatation deformation failure mechanism of roadway surrounding rock in deep-buried slowly inclined jointed rock mass was revealed. The failure reasons of the support structure were analyzed, and the relevant support principles were proposed. The research results can provide scientific references for the stability control of roadways excavated in jointed rock mass.

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Experimental and Numerical Study of the Uniaxial Compressive Stress-Strain Relationship of a Rock Mass with Two Parallel Joints

Archives of Civil Engineering ◽

10.2478/ace-2019-0019 ◽

2019 ◽

Vol 65 (2) ◽

pp. 67-80

Author(s):

L. X. Xiong ◽

H. Y. Yuan ◽

Y. Zhang ◽

K. F. Zhang ◽

J. B. Li

Keyword(s):

Compressive Strength ◽

Rock Mass ◽

Uniaxial Compressive Strength ◽

Numerical Study ◽

Jointed Rock ◽

Jointed Rock Mass ◽

Rock Bridge ◽

Vertical Loading ◽

Joint Fracture ◽

Dip Angle

AbstractA “rock bridge”, defined as the closest distance between two joints in a rock mass, is an important feature affecting the jointed rock mass strength. Artificial jointed rock specimens with two parallel joint fractures were tested under uniaxial compression and numerical simulations were carried out to study the effects of the inclination of the rock bridge, the dip angle of the joint, rock bridge length, and the length of joints on the strength of the jointed rock mass. Research results show: (1) When the length of the joint fracture, the length of the rock bridge, and the inclination of the rock bridge stay unchanged, the uniaxial compressive strength of the specimen gradually increases as the inclination of the joint fracture increases from 0°to 90°. (2) When the length of the joint fracture, the length of the rock bridge, and the inclination of the joint fracture stay unchanged, the uniaxial compressive strength of the specimen shows variations in trends with the inclination of the rock bridge increasing from 30° to 150° (3). In the case when the joint is angled from the vertical loading direction, when the dip angle of the joint fracture, the inclination of the rock bridge, and the length of the rock bridge stay unchanged, the uniaxial compressive strength of the specimen gradually decreases with an increasing length of joint fracture. When the dip angle of the joint fracture, the inclination of the rock bridge, and the length of the joint fracture stay unchanged, the uniaxial compressive strength of the specimen does not show a clear trend with an increase of the length of the rock bridge.

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