Rock breaking mechanism in percussive drilling with the effect of high-frequency torsional vibration

2019 ◽  
pp. 1-15 ◽  
Author(s):  
Jialin Tian ◽  
Changyue Fan ◽  
Tangjia Zhang ◽  
Yi Zhou
Keyword(s):  
Torsional Vibration ◽  
High Frequency ◽  
Rock Breaking ◽  
Percussive Drilling ◽  
Breaking Mechanism

scholarly journals Optimal Design Parameters of a Percussive Drilling System for Efficiency Improvement

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Changheon Song ◽  
Jintai Chung ◽  
Jae-Sang Cho ◽  
Yun-Joo Nam
Keyword(s):  
Optimal Design ◽  
Resistance Coefficient ◽  
Rock Breaking ◽  
Performance Estimation ◽  
Design Parameters ◽  
Percussive Drilling ◽  
Rock Interaction ◽  
Breaking Mechanism ◽  
And Performance ◽  
The Impact

This paper aims to determine the optimal design parameters for percussive drilling systems considering the bit-rock interaction. First, the motion dynamics of a bit impacted by a dropped piston are modeled by impact stress propagation and a rock-breaking mechanism representing the penetration resistance coefficient and unloading constant. Next, the damping vibration behavior of the bit is investigated considering the impact duration and the rock loading/unloading condition. In addition, the proposed dynamics are simplified by adopting two dimensionless parameters representing the bit-piston mass ratio and the rock-piston stiffness ratio. Finally, the drilling efficiency, defined by the energy transmitted from the piston to the rock, is presented in terms of the proposed parameters. The use of optimal design parameters for percussive drilling systems improved the drilling efficiency. These results are applicable to the design and performance estimation of down-the-hole and top-hammer systems.

Study on Rock-Breaking Simulation and Experiment of Double Disc Cutter of TBM

2016 ◽  
Vol 23 ◽  
pp. 80-88
Author(s):  
F. Lu ◽  
C. Zhang ◽  
J. Sun ◽  
J.X. Tian ◽  
M. Liu ◽  
...  
Keyword(s):  
Rock Breaking ◽  
Disc Cutter ◽  
Element Analysis ◽  
Breaking Effect ◽  
The Finite Element Analysis ◽  
Breaking Mechanism ◽  
Simulation And Experiment ◽  
Tbm Cutter ◽  
Cutter Spacing ◽  
The Impact

In order to improve working efficiency of the tunneling process and extend working life of disc cutter, explore the impact of cutter spacing and loading for the cutter rock-breaking effect. With the theory of rock crushing, Based on the finite element analysis software ABAQUS, the process of disc cutter breaking rock is simulated, considering the adjacent cutters sequential constraints, then, to make sure two cutter space with the method of SE in experiment.The simulation results showed that the optimal cutter spacings were both about 80mm in the same loading and the sequentially loading, but the rock-breaking effect of sequentially loading is better than the same loading. The experimental data showed that the minimum specific energy of rock breaking is appeared cutter spacing between 80mm and 90mm. Thus, the correctness and rationality of the simulation was verified. The study is good for understanding the rock-breaking mechanism of double disc cutter and has a certain promoting value to optimize TBM cutter system.Keywords:TBM, rock fragmentation, ABAQUS, cutter spacing, sequentially cutting

scholarly journals Rock Breaking Mechanism and Drilling Performance of Harmonic Vibro-Impact Drilling

2020 ◽  
Vol 570 ◽  
pp. 022036
Author(s):  
Siqi Li ◽  
Shenglei Tian ◽  
Wei Li ◽  
Zhao Huan ◽  
Xin Ling ◽  
...  
Keyword(s):  
Rock Breaking ◽  
Drilling Performance ◽  
Breaking Mechanism

scholarly journals Theoretical and Numerical Research on V-Cut Parameters and Auxiliary Cuthole Criterion in Tunnelling

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Xiaoming Lou ◽  
Bao Wang ◽  
En Wu ◽  
Mingwu Sun ◽  
Ping Zhou ◽  
...  
Keyword(s):  
Numerical Modelling ◽  
Cutting Parameters ◽  
Rock Breaking ◽  
Theoretical Solution ◽  
Critical Depth ◽  
Forming Mechanism ◽  
Breaking Mechanism ◽  
Numerical Research ◽  
Explosive Properties ◽  
Dip Angle

This paper aims at providing a sound theoretical solution to auxiliary central hole and the cutting parameters. For this purpose, the forming mechanism of V-cut cavity for cutting blasting was performed based on the hypothetical rock breaking mechanism of V-cut blasting. A theoretical solution for increasing the critical depth of the auxiliary center cuthole and the criteria for increasing the cuthole diameter of various types of cutholes when the rock attributes, explosive properties, and cuthole dip angle are constant are proposed. (1) If charging length le < 0.75H/sin θ, no auxiliary cuthole is needed. (2) If 0.75H/sin θ < le < 0.75H/sin θ + (2∼4) × 0.1, a central vertical auxiliary hole is needed. (3) If 0.75H/sin θ + (2∼4) × 0.1 < le < 0.75(H/sin θ + Hi/sin θi), a shallow inclined hole is needed. (4) If le > 0.75(H/sin θ + Hi/sin θi), both the central vertical cuthole and the shallow inclined cuthole are needed. Meanwhile, the theoretical solution was verified by numerical modelling with ANSYS/LS-DYNA. Moreover, the field implementation of the V-cut and the auxiliary hole effectively improved the blasting effect in both efficiency and economy.

High frequency torsional vibration of vehicular driveline systems in clonk

2002 ◽  
Vol 9 (2) ◽  
pp. 127 ◽  
Author(s):  
A. Farshidianfar ◽  
M. Ebrahimi ◽  
H. Rahnejat ◽  
M. T. Menday
Keyword(s):  
Torsional Vibration ◽  
High Frequency
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