Numerical study of the influence of hydrostatic and confining pressure on percussive drilling of hard rock

2016 ◽  
Vol 76 ◽  
pp. 120-128 ◽  
Author(s):  
Timo Saksala
Keyword(s):  
Hard Rock ◽  
Numerical Study ◽  
Confining Pressure ◽  
Percussive Drilling

Experimental and Numerical Study of a New Percussive Drilling Model With a Drift

2003 ◽  
Author(s):  
Luiz Fernando P. Franca ◽  
Hans Ingo Weber
Keyword(s):  
Numerical Analysis ◽  
Chaotic Motion ◽  
Hard Rock ◽  
Penetration Rate ◽  
Numerical Study ◽  
Experimental Investigations ◽  
Harmonic Load ◽  
Percussive Drilling ◽  
Forward Motion ◽  
Stick Slip

New drilling techniques have been studied to increase the penetration in hard rock. These techniques use harmonic load and, in some cases, also impacts to generate a greater penetration rate. Analyzing only a percussive penetration phenomenon, the new model presented in this paper allows the forward motion (with a drift) in stick-slip condition without impact. Numerical and experimental investigations are presented and are qualitatively compared. Expanding the numerical analysis it is shown that the behavior may vary from periodic to chaotic motion.

scholarly journals A numerical study of the influence from pre-existing cracks on granite rock fragmentation at percussive drilling

2014 ◽  
Vol 39 (5) ◽  
pp. 558-570 ◽  
Author(s):  
Mahdi Saadati ◽  
Pascal Forquin ◽  
Kenneth Weddfelt ◽  
Per-Lennart Larsson ◽  
Francois Hild
Keyword(s):  
Numerical Study ◽  
Rock Fragmentation ◽  
Percussive Drilling ◽  
Granite Rock

Surrounding Rock Stress and Deformation Evolution Character Analysis of Circular Openings in Deep Underground Engineering

2011 ◽  
Vol 418-420 ◽  
pp. 2001-2005
Author(s):  
Ai Ping Yuan ◽  
Mao Wei Ji ◽  
Dai Qiang Deng
Keyword(s):  
Hard Rock ◽  
Confining Pressure ◽  
Surrounding Rock ◽  
Rock Stress ◽  
Underground Engineering ◽  
High Confining Pressure ◽  
Deep Underground ◽  
Stress And Deformation ◽  
Peak Value ◽  
Surrounding Rock Stress

Hard rock generally performs ideal plastic character after the stress reaches its peak value with high confining pressure. Once the plastic strain satisfies certain condition, the brittle failure occurs, and the rock mass located in the residual region. Based on the mechanical model of hard rock under high confining pressure, we studied the surrounding rock stress and deformation evolution law of circular openings. The results shows that there is a significant end constraint effect at the opening face, and the deformation induced by disturbance is about one sixth of its total value. The results can provide theoritical foundation for deep underground engineer lining design.

Numerical Study on Zonal Disintegration of Deep Rock Mass Using Three-Dimensional Bonded Block Model

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Qingteng Tang ◽  
Wenbing Xie ◽  
Xingkai Wang ◽  
Zhili Su ◽  
Jinhai Xu
Keyword(s):  
Rock Mass ◽  
Fracture Zone ◽  
Numerical Study ◽  
Confining Pressure ◽  
Surrounding Rock ◽  
Zonal Disintegration ◽  
Block Model ◽  
Deep Rock Mass ◽  
Damaged Zone ◽  
Deep Rock

Zonal disintegration, a phenomenon of fractured zones and intact zones distributed alternately in deep rock mass, is different from the excavation-damaged zone of shallow rock mass. In this study, bonded block model of 3DEC was employed to study the fracture mode and origination condition of zonal disintegration. Initiation, propagation, and coalescence progress of fracture around the roadway boundary under different triaxial stress conditions are elaborated. Numerical simulation demonstrated that zonal disintegration may occur when the direction of maximum principal stress is parallel to the roadway axis. It is interesting to find that the fracture around the roadway boundary traced the line of a spiral line, while slip-line fractures distributed apart from the roadway boundary. The extent of the alternate fracture zone decreased as the confining pressure increased, and alternate fracture zone was no longer in existence when the confining pressure reaches a certain value. Effects of roadway shape on zonal disintegration were also studied, and the results indicated that the curvature of the fracture track line tends to be equal to the roadway boundary in shallow surrounding rock of the roadway, while the fractures in deep surrounding rock seems unaffected by the roadway shape. Those findings are of great significance to support design of deep underground openings.

scholarly journals Failure Mechanism of Rock Specimens with a Notched Hole under Compression—A Numerical Study

2021 ◽  
Vol 11 (17) ◽  
pp. 7797
Author(s):  
Amin Manouchehrian ◽  
Pinnaduwa H. S. W. Kulatilake ◽  
Rui Wu
Keyword(s):  
Numerical Study ◽  
Confining Pressure ◽  
Compressive Test ◽  
Separate Model ◽  
Failure Evolution ◽  
Uniaxial Compressive Test ◽  
Notch Length ◽  
The Stability ◽  
Fracturing Mechanism ◽  
Rock Specimens

Discontinuities are natural structures that exist in rocks and can affect the stability of rock structures. In this article, the influence of notch presence on the strength and failure evolution around a hole in compressed rock specimens is investigated numerically. Firstly, the uniaxial compressive test on a rock specimen with a circular hole is modeled, and the failure evolution in the specimen is simulated. In a separate model, notches are created at the surface of the hole. Results show that, when the notches are created in the model, a failure zone around the hole is transferred to a distance away from the surface of the hole. In addition, a parametric study is carried out to investigate the influence of the notch length and the confining pressure on the fracturing behavior of the specimen. Numerical results presented in this article indicate that the presence of notches at the surface of the hole and their dimensions can affect the fracturing mechanism of the specimen. In some cases, the failure at the boundary of the hole is prevented when the notches of certain dimensions are added to the hole. The insights gained from this numerical study may be helpful to control the failure around underground excavations.

A Self-Optimizing Control System for Hard Rock Percussive Drilling

2008 ◽  
Vol 13 (2) ◽  
pp. 153-157 ◽  
Author(s):  
Gary L. Cavanough ◽  
Mark Kochanek ◽  
Jock B. Cunningham ◽  
Ian D. Gipps
Keyword(s):  
Control System ◽  
Hard Rock ◽  
Percussive Drilling ◽  
Optimizing Control
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