On the rock-breaking mechanism of plasma channel drilling technology

AbstractIncreasing drilling speed and efficiency of hard formation for deep and ultra-deep well is one of the international recognized drilling problems and key technologies to be tackled urgently. Particle jet impact drilling technology is an efficient non-contact rock-breaking method to overcome slow drilling speed, which has great development and application potential in drilling speed-increase of hard formation and deep well. High efficiency drilling technology and rock-breaking speed-increase mechanism in high temperature, high pressure and high hardness formations of deep and ultra-deep wells were mainly focused and keynoted in this paper. With extensive investigation of domestic and foreign literature, the working principle, key technical devices, deep-well-rock mechanical characteristic, unconventional constitutive model and rock-breaking mechanism of particle jet impact drilling technology were analyzed, which proved the feasibility and high efficiency for deep and hard stratum, and also, dynamic failure mechanism of rock needs to be elaborated by constructing the constitutive model with high temperature and pressure. Meanwhile, the major problems to be solved at present and development direction future were summarized, which mainly included: miniaturization of drilling equipment and individualization of drilling bit; optimization of jet parameters and the evaluation method of rock-breaking effect; establishment of mechanical property and unconventional constitutive model of deep-well-rock; rock-breaking mechanism and dynamic response under particle jet coupling impact. The research can help for better understanding of deep-well drilling speed-increasing technology and also promote the development and engineering application of particle jet impact drilling speed-increase theory and equipment.

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Dynamic Analysis of Percussion Drilling System under Harmonic Impact

Shock and Vibration ◽

10.1155/2021/8892144 ◽

2021 ◽

Vol 2021 ◽

pp. 1-11

Author(s):

Yijin Zeng ◽

Shidong Ding ◽

Jinchao Xu ◽

Qunai Hu ◽

Xiaojie Cui

Keyword(s):

Excitation Frequency ◽

Harmonic Excitation ◽

Rock Breaking ◽

Simplified Model ◽

Vibration Displacement ◽

Impact System ◽

Drilling Technology ◽

Vibration Impact ◽

Breaking Mechanism ◽

The Impact

As a new efficient rock-breaking technology, harmonic impact drilling technology has received great attention, but the research on its rock-breaking mechanism is insufficient, which limits its development. Based on the theory of vibration, a simplified model of high-frequency harmonic vibration impact system is established in this paper. The numerical model was solved by Matlab and the motion equations of drill bit and rock at different stages of motion are obtained, respectively. Based on the factor analysis of the mathematical model, the dynamic characteristics of the impact system under harmonic excitation are studied. Finally, numerical simulations are carried out to further analyze the drilling effect of harmonic impact drilling and verify the correctness of the simplified model. The results show that when the excitation frequency equals the resonance frequency of rock, the vibration displacement of rock reaches the peak value. The drilling speed is greatly increased by harmonic impact drilling compared with conventional drilling.

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

International Journal of Engineering Research in Africa ◽

10.4028/www.scientific.net/jera.23.80 ◽

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

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

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/570/2/022036 ◽

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

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

Advances in Materials Science and Engineering ◽

10.1155/2020/8568153 ◽

2020 ◽

Vol 2020 ◽

pp. 1-13 ◽

Cited By ~ 2

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.

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