Hard-Rock Breaking

2021 ◽  
pp. 121-125
Author(s):  
Cedric E. Gregory
Keyword(s):  
Hard Rock ◽  
Rock Breaking

The Technical Development for Increasing ROP with Particle Impact Drilling in China

2014 ◽  
Vol 904 ◽  
pp. 292-295 ◽  
Author(s):  
Jian Zhao ◽  
Yi Ji Xu
Keyword(s):  
Field Test ◽  
Hard Rock ◽  
Rock Breaking ◽  
Particle Impact ◽  
Sound Effect ◽  
Deep Well ◽  
Working Principle ◽  
Hard Formation ◽  
Field Test Result ◽  
Test Result

Field test of particle impact drilling (PID) technology was firstly carried out in deep well and hard formation in Sichuan province china on Oct. 2013. The test formation was named Xu Jiahe, which was very difficult to penetration. Field test result shows that the ROP (rate of penetration) was nearly doubled by this technology. It indicates that there is a profound application prospect of particle impact drilling, especially for hard rock formation. In this paper, the equipment and working principle was analyzed. The experiment and simulation results showed that the rock breaking efficiency was highly increased by this technology. The details of this field test were presented too in this paper that proved the sound effect of PID.

scholarly journals Rock Breaking Performance of TBM Disc Cutter Assisted by High-Pressure Water Jet

2020 ◽  
Vol 10 (18) ◽  
pp. 6294
Author(s):  
Fengchao Wang ◽  
Dapeng Zhou ◽  
Xin Zhou ◽  
Nanzhe Xiao ◽  
Chuwen Guo
Keyword(s):  
High Pressure ◽  
Hard Rock ◽  
Rock Breaking ◽  
Water Jet ◽  
Disc Cutter ◽  
Pressure Water ◽  
High Pressure Water Jet ◽  
Full Face ◽  
Rock Tunnel ◽  
Digging Efficiency

A high-pressure water jet can break rock efficiently, which is of great potential to overcome the problems of a tunnel boring machine (TBM) in full-face hard rock tunnel digging, such as low digging efficiency and high disc cutter wear rate. Therefore, this paper presented a new tunneling method that is a TBM coupled with a high-pressure water jet. The rock failure mechanism under the coupled forces of a disc cutter and water jet was analyzed at first. Then, the finite element method (FEM) and smoothed particle hydrodynamics (SPH) method were used to establish a numerical model of rock broken by the disc cutter and water jet. Effects of parameters on rock breaking performance were studied based on the numerical model. Moreover, an experiment of the water jet cutting marble was carried out to verify the reliability of the numerical simulation. Results showed that the high-pressure water jet can increase the TBM digging efficiency and decrease the forces and wear rate of the disc cutter. The optimum nozzle diameter is 1.5 mm, while the optimum jet velocity is 224.5 m/s in this simulation. The results can provide theoretical guidance and data support for designing the most efficient system of a TBM with a water jet for digging a full-face hard rock tunnel.

Experimental Investigation of Hard Rock Breaking Using a Conical Pick Assisted by Abrasive Water Jet

2020 ◽  
Vol 53 (9) ◽  
pp. 4221-4230 ◽  
Author(s):  
Songyong Liu ◽  
Fangyue Zhou ◽  
Hongsheng Li ◽  
Yueqiang Chen ◽  
Fengchao Wang ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Hard Rock ◽  
Rock Breaking ◽  
Water Jet ◽  
Abrasive Water Jet ◽  
Conical Pick

scholarly journals Rock Breaking by Conical Pick Assisted with High Pressure Water Jet

2014 ◽  
Vol 6 ◽  
pp. 868041 ◽  
Author(s):  
Liu Songyong ◽  
Chen Junfeng ◽  
Liu Xiaohui
Keyword(s):  
Numerical Simulation ◽  
High Pressure ◽  
Hard Rock ◽  
Rock Breaking ◽  
Water Jet ◽  
Cutting Efficiency ◽  
Conical Pick ◽  
Pressure Water ◽  
High Pressure Water Jet ◽  
Better Than

In the process of hard rock breaking, the conical pick bears great cutting force and wear, and the cutting efficiency is lower. Thus different combination ways of water jet and conical pick were proposed to solve this issue; for instance, water jet placed in the front of pick (JFP) and water jet through the center of pick (JCP) was researched by numerical simulation and experiments in this paper. First, the models of rock breaking were built based on SPH combined with finite element method. Then, the stress distribution of rock and the cut force of pick were analyzed when the rock broken by the conical pick assisted with the high pressure water jet. It indicates that the effect of the JCP on rock breaking is better than the JFP. At last, experiments about rock breaking with a conical pick and the JCP were conducted to verify the reliability of the simulation. It indicates that the rock breaking with the assistance of high pressure water jet cannot only reduce the pick force, but also increase the rock crushing volume.

scholarly journals Research on the Hard-Rock Breaking Mechanism of Hydraulic Drilling Impact Tunneling

2015 ◽  
Vol 2015 ◽  
pp. 1-34 ◽  
Author(s):  
Risheng Long ◽  
Shaoni Sun ◽  
Zisheng Lian
Keyword(s):  
Hard Rock ◽  
Equivalent Stress ◽  
Rock Breaking ◽  
Free Surfaces ◽  
Hydraulic Impact ◽  
Breaking Mechanism ◽  
Von Mises Equivalent Stress ◽  
Von Mises ◽  
The Impact ◽  
Impact Distance

In order to realize the rapid hard-rock tunneling in a safe, highly effective, and economic manner, the hydraulic drilling impact hard-rock tunneling (HDIHT) technology and method were introduced based on the theories of rock mechanics and hydraulic impact. The key parameters, including drilling radius and impact distance, were researched to reveal the stress behavior during HDIHT process. The Von Mises equivalent stress and its principal stress components were analyzed, and the breaking mechanism of HDIHT was also discussed. The simulation results show that, to ensure the effectiveness of “secondary breaking” caused by drilling hole free surfaces, the impact distance should not exceed 200 mm, and the optimal drilling radius was about 35 mm.

Research and Development of Pneumatic Anchor Rock Driller & Drilling Tools

2011 ◽  
Vol 90-93 ◽  
pp. 56-60
Author(s):  
Hong Li Wang ◽  
Jin Qiao Zhao ◽  
Wei Bao ◽  
Li Xin Song
Keyword(s):  
Hard Rock ◽  
Soft Rock ◽  
Rock Breaking ◽  
Production Costs ◽  
Impact Function ◽  
Drilling Parameters ◽  
Drilling Tools ◽  
Breaking Mechanism ◽  
Drilling Rigs ◽  
Rock Tunnel

Now, pneumatic rotary anchor roofbolter is widely used in the underground. Pneumatic rock driller is mainly operated in hard rock tunnel, but it often exists in the phenomenon of hard rock and soft rock sections alternately. The result is occured in the replacement of drilling rigs and drilling tools, to produce a great deal of inconvenience. This not only affects seriously anchorage operating speed, but also increases production costs and brings insecurities factors of replacing driller. This study analyzes the performance and parameters of traditional rock rigs & roofbolter. Mechanical Model is established on the basis of studying rock breaking mechanism. Drilling parameters are comprehensively evaluated. It is put forword of specific rotary-impact function of pneumatic anchor rock driller. On this basis, specific rotary-impact function of pneumatic anchor rock driller has been systematically studied.

scholarly journals Study on Optimum Free-face Condition of Cutting Hard Rock with Tunnel Boring Machine Hob

2021 ◽  
Author(s):  
Xuhui Zhang ◽  
Yashi Liao ◽  
Zhongxiang Chen ◽  
Yimin Xia ◽  
Kui Zhang
Keyword(s):  
Crack Propagation ◽  
Hard Rock ◽  
Reaction Force ◽  
Specific Energy Consumption ◽  
Tunnel Boring Machine ◽  
Rock Cutting ◽  
Rock Breaking ◽  
Free Face ◽  
Tunnel Boring ◽  
Rock Chip

To explore the rock-breaking characteristics of cutting hard rock under free-face condition by tunnel boring machine (TBM) hob and obtain the optimum free-face condition, the rock-breaking processes such as crack propagation, amount of micro crack and reaction force with penetration depth are first investigated based on discrete element simulation method. Then, the crack length, rock chip area, specific energy consumption etc. with different free-face spacing (S) and free-face height (H) are studied combined with rock-cutting simulation and experiment. The research results show that the formation of the rock chip under free-face condition by TBM hob is driven by tensile failure, and it exists an optimum free-face condition with the S of 80 mm and the H of 200 mm to promote main crack propagation and enhance the rock-cutting efficiency, which can provide a reference for the application of rock-breaking technology under the free-face.

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