The Rock-Breaking Mechanism of Directional Fracture Blast Using an Irregular Shape Cartridge and Its Field Application

2018 ◽  
Vol 47 (2) ◽  
pp. 20160496 ◽  
Author(s):  
Yanbing Wang
Keyword(s):  
Rock Breaking ◽  
Field Application ◽  
Irregular Shape ◽  
Breaking Mechanism

scholarly journals 3D Numerical Simulation of Rock Cutting of an Innovative Non-Planar Face PDC Cutter and Experimental Verification

2019 ◽  
Vol 9 (20) ◽  
pp. 4372 ◽  
Author(s):  
Jianxun Liu ◽  
Hualin Zheng ◽  
Yuchun Kuang ◽  
Han Xie ◽  
Chao Qin
Keyword(s):  
Polycrystalline Diamond ◽  
Element Model ◽  
Rake Angle ◽  
Rock Breaking ◽  
Field Application ◽  
Planar Structure ◽  
Rock Properties ◽  
Cutting Depth ◽  
Rotational Angle ◽  
Breaking Mechanism

The low rock breaking efficiency of conventional polycrystalline diamond compact (PDC) bits in hard abrasive formations prompts the development of PDC cutting elements from the planar structure to the non-planar structure. As an innovative non-planar cutter, the design and research of the three-ridged diamond element (3-RDE) cutter is still in its infancy, and its rock breaking mechanism and laws are not yet clear. In this paper, a three-dimensional (3D) finite element model of dynamic rock breaking with 3-RDE cutter has been established. The accuracy of the numerical model was verified by experimental data. Then, the difference of rock breaking mechanism between 3-RDE cutter and conventional cutter was studied. The effects of back-rake angle, cutting depth, rotational angle, and rock properties on rock breaking efficiency were also analyzed. The results show that, unlike the conventional PDC shear rock breaking cutter, the 3-RDE cutter breaks rock mainly by crushing and shearing, and the rock breaking efficiency is higher. A small back-rake angle and reasonable cutting depth contribute to improving the rock breaking efficiency; the existence of rotational angle is not conductive to the rock breaking. The field application shows that compared with the conventional cutter, the 3-RDE cutter is easier to penetrate into the formation, and is more stable with less torque required. The research results can be of benefit to the design and manufacture of 3-RDE PDC bits.

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.

scholarly journals Rock‐breaking mechanism and efficiency of straight‐swirling mixed nozzle for the nondiagenetic natural gas hydrate in deep‐sea shallow

2020 ◽  
Vol 8 (10) ◽  
pp. 3740-3752
Author(s):  
Yang Tang ◽  
Peng Sun ◽  
Guorong Wang ◽  
Biwei Fu ◽  
Jiaxin Yao
Keyword(s):  
Natural Gas ◽  
Gas Hydrate ◽  
Deep Sea ◽  
Rock Breaking ◽  
Natural Gas Hydrate ◽  
Breaking Mechanism

Design and Study on a Vertical Comprehensive Experimental Platform for Function between Disc Cutter and Rock

2013 ◽  
Vol 798-799 ◽  
pp. 361-364
Author(s):  
Huan Huan Feng ◽  
Kui Chen ◽  
Jian Jun Zhou ◽  
Feng Yuan Li ◽  
Zhu Feng Wang
Keyword(s):  
Rock Breaking ◽  
Disc Cutter ◽  
Characteristic Analysis ◽  
Experimental Platform ◽  
Experiment Platform ◽  
Engineering Data ◽  
Electronic Control System ◽  
Breaking Mechanism ◽  
Rolling Experiment ◽  
Simulated Motion

For better research on rock breaking mechanism of shield disc cutter, a kind of vertical experimental platform was designed after the characteristic analysis of existing linear cutting rig, using rock box turning to realize the rotary simulated motion of shield disc cutter. Compared with the linear device, this experiment platform overcomes the lack of real simulation of shield disc cutter movement condition. The design of comprehensive experimental platform was described particularly from the three aspects of electronic control system, hydraulic system and an adjusting device for cutter space. On the produced platform, which is the first one in China, the experiments of rolling experiment under three cutters sequential indentation were performed. The experimental data and analysis result were basically consistent with engineering data and simulation result based on RFPA. The correctness of design scheme, advancement and scientificalness of experiment platform were confirmed, with the hoping of providing dependable platform for the research on rock breaking mechanism of shield disc cutter.

scholarly journals Development and Application of the Downhole Drilling String Shock-Absorption and Hydraulic Supercharging Device

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Yongwang Liu ◽  
Zhichuan Guan ◽  
Hongning Zhang ◽  
Bo Zhang
Keyword(s):  
Longitudinal Vibration ◽  
Rock Breaking ◽  
Drill String ◽  
Field Application ◽  
Drilling Speed ◽  
Technical Design ◽  
Fundamental Study ◽  
String Vibration ◽  
Drilling String ◽  
Breaking Energy

It is a hot topic for deep/ultradeep wells to improve rock-breaking efficiency and drilling speed by available downhole energy. Based on different downhole energies and working conditions, specialized plunger pump is proposed to convert longitudinal vibration of drilling string into rock-breaking energy. Technical design is developed to generate high-pressure water jet. And then a simulation model is built to verify feasibility of the technical design. Through simulation, the influence law of key factors is obtained. On this basis, this device is tested in several wells. The result indicates this device can increase drilling speed as much as 136%. Meanwhile the harmful vibration can be absorbed. The energy from drilling string vibration is of high frequency and increases as well depth and formation anisotropy increase. By reducing adverse vibration, this device is able to increase the drilling speed and the service life also meets the demand of field application. The longest working time lasts for more than 130 hours. The performance of this device demonstrates great application prospect in deep/ultradeep resources exploration. To provide more equipment support for deep/ultradeep wells, more effort should be put into fundamental study on downhole drill string vibration and related equipment.

scholarly journals Simulation and Experimental Study of the Rock Breaking Mechanism of Personalized Polycrystalline Diamond Compact Bits

2020 ◽  
Vol 13 (5) ◽  
pp. 122-131
Author(s):  
Yu Jinping ◽  
◽  
Zou Deyong ◽  
Sun Yuanxiu ◽  
Zhang Yin
Keyword(s):  
Experimental Study ◽  
Finite Element ◽  
Tensile Stress ◽  
Crack Propagation ◽  
Tangential Force ◽  
Polycrystalline Diamond ◽  
Rock Breaking ◽  
Pdc Bit ◽  
Breaking Mechanism ◽  
Polycrystalline Diamond Compact

Rock breaking is a complex physical process that can be influenced by various factors, such as geometrical shape and cutting angle of rock breaking tools. Experimental study of the rock breaking mechanism of personalized bits is restricted due to long cycle and high cost. This study simulated the rock breaking mechanism of polycrystalline diamond compact (PDC) bit by combining finite element method and experiment. The simulation was performed to shorten the period and reduce the cost of studying the rock breaking mechanism of PDC bits. A rock breaking finite element model for sting cutters of personalized PDC bit was established to simulate the rock breaking process. The crack propagation pattern, dynamic stress of rock breaking, and rock breaking mechanism of sting cutters of personalized PDC bit were analyzed. The correctness of the simulation results was verified through experiments. Results demonstrate that the rock breaking load increases with the crack propagation in the fracture initiation and propagation stages, with the maximum tangential force of 1062.5 N and maximum axial force of 1850.0 N. The load changes in a small range when the crack penetrates the rock, with the tangential force of 125.0–500.0 N and axial force of 375.0–875.0 N. The rock breaking mechanism of the sting cutters of bit is consistent with maximum tensile stress theory. The rock begins to break when the tensile stress of rock is 36.9 MPa. The sting cutters of personalized PDC bit have better wear resistance than the sting cutters of conventional bit. The average wear rates of personalized PDC and conventional bits are 1.74E-4 and 2.1E-4 mm/m, respectively. This study serves as reference for shortening the study period of rock breaking mechanism, efficiently designing personalized PDC bit structure, reducing bit wear, and enhancing rock breaking efficiency.

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