Slant Angle and Its Influence on Rock Cutting Performance

Rock cutting is an important aspect of the civil engineering, for example, tunnelling. To improve cutting efficiency, it is important to understand the rock failure (fracture) mechanisms and the influences of cutting parameters on rock fracture behaviour. This study identified that the relative position of a pick (rock cutting tool) to the rock surface is critical to the cutting performance of the pick during rock cutting process. However, the pick tilt angle commonly used by the industries is not sufficient to describe this relative position. To address this issue, a new angle named “slant angle” is introduced. The slant angle of a pick is determined by its tilt angle and the inclination angle of the rock surface. The calculation of the slant angle is presented. A series of laboratory rock cutting experiments were conducted to investigate the influence of the slant angle on cutting force and rock fracture pattern, and two new findings were made: (1) the rotational angle of the groove cut by a tilted pick was possibly different from the tilt angle and (2) all forces on a pick increased significantly with the increase of the slant angle. The findings of this study can help improve the rock cutting efficiency.

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Numerical Simulation of Rock Plate Cutting with Three Sides Fixed and One Side Free

Advances in Materials Science and Engineering ◽

10.1155/2018/5464295 ◽

2018 ◽

Vol 2018 ◽

pp. 1-21 ◽

Cited By ~ 4

Author(s):

Zhenguo Lu ◽

Lirong Wan ◽

Qingliang Zeng ◽

Xin Zhang ◽

Kuidong Gao

Keyword(s):

Numerical Simulation ◽

Cutting Force ◽

Cutting Speed ◽

Rock Cutting ◽

Numerical Results ◽

Peak Force ◽

Cutting Performance ◽

Conical Pick ◽

Cutting Method ◽

Cutting Angle

In order to overcome conical pick wear in the traditional rock cutting method, a new cutting method was proposed on account of increasing free surface of the rock. The mechanical model of rock plate bending under concentrated force was established, and the first fracture position was given. The comparison between experimental and numerical results indicated that the numerical method is effective. A computer code LS-DYNA (3D) was employed to study the cutting performance of a conical pick. To study the rock size influenced on the cutting performance, the numerical simulations with different thickness, width, and height of a rock plate was carried out. The numerical simulation with the different cutting parameters of cutting speed, cutting angle, and cutting position influenced on cutting performance was also carried out. The numerical results indicated that the peak force increased with the increasing thickness of rock plate. With the increasing width and height of the rock plate, the peak force decreased and then became stable. Besides, the peak force decreased with the increasing of cutting position lxp/lx. Moreover, the peak force increased and then decreased with the increasing of cutting angle. The cutting speed has nonsignificant influence on the peak force. The strong exponential relationship was obtained between the peak force and cutting position, thickness, height, and width of the rock plate at a confidence level of 0.95. A binomial relationship was observed between the peak force and cutting angel. The cutting force comparison between traditional rock cutting and rock plate cutting indicated that the new cutting method can effectively reduce peak cutting force.

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A New Approach of Rock Cutting Efficiency Evaluation by using Plastic Energy Dissipation Ratio

KSCE Journal of Civil Engineering ◽

10.1007/s12205-018-0100-0 ◽

2018 ◽

Vol 23 (2) ◽

pp. 879-888

Author(s):

Weiji Liu ◽

Xiaohua Zhu

Keyword(s):

Energy Dissipation ◽

Rock Cutting ◽

Efficiency Evaluation ◽

Cutting Efficiency ◽

New Approach ◽

Plastic Energy ◽

Energy Dissipation Ratio

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Effect of Abrasive Feed Rate on Rock Cutting Performance of Abrasive Waterjet

Rock Mechanics and Rock Engineering ◽

10.1007/s00603-019-01784-x ◽

2019 ◽

Vol 52 (9) ◽

pp. 3431-3442 ◽

Cited By ~ 2

Author(s):

Tae-Min Oh ◽

Gun-Wook Joo ◽

Gye-Chun Cho

Keyword(s):

Feed Rate ◽

Rock Cutting ◽

Cutting Performance ◽

Abrasive Waterjet

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Rock Customized Shaped Cutters Improve Rock Cutting Efficiency

10.2118/194148-ms ◽

2019 ◽

Author(s):

Reza Rahmani

Keyword(s):

Rock Cutting ◽

Cutting Efficiency

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Effects of Focus Geometry on the Hard Rock-Cutting Performance of an Abrasive Waterjet

Advances in Civil Engineering ◽

10.1155/2020/1650914 ◽

2020 ◽

Vol 2020 ◽

pp. 1-13 ◽

Cited By ~ 1

Author(s):

Yohan Cha ◽

Tae-Min Oh ◽

Gye-Chun Cho

Keyword(s):

Momentum Transfer ◽

Hard Rock ◽

Empirical Relationship ◽

Abrasive Particle ◽

Rock Cutting ◽

Maximum Energy ◽

Cutting Performance ◽

Granitic Rocks ◽

Abrasive Waterjet ◽

Cutting Depth

Abrasive waterjets are being increasingly used in civil engineering for rock and concrete cutting, particularly for the demolition or repair of old structures. The energy of an abrasive waterjet is primarily provided by the accelerated abrasive. The momentum transfer during mixing and acceleration determines the abrasive velocity, which affects the cutting performance. Meanwhile, the geometry of the focus at which mixing occurs influences the momentum transfer efficiency. In this study, the effects of the focus geometry on the optimum abrasive flow rate (AFR) and momentum transfer characteristics in hard rock cutting were investigated. Experiments were conducted using granite specimens to test the AFR under different focus geometry conditions such as diameter and length. The results show that the focus geometry significantly affects the maximum cutting depth and optimum AFR. The maximum cutting energy was analyzed based on the cutting efficiency of a single abrasive particle. In addition, the momentum transfer parameter (MTP) was evaluated from the empirical relationship between the maximum energy and the cutting depth for granitic rocks. Accordingly, a model for estimating the MTP based on the AFR was developed. It is expected that the results of this study can be employed for the optimization of waterjet rock cutting.

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Investigation of the influence mechanism of rock damage on rock fragmentation and cutting performance by the discrete element method

Royal Society Open Science ◽

10.1098/rsos.190116 ◽

2019 ◽

Vol 6 (5) ◽

pp. 190116 ◽

Cited By ~ 6

Author(s):

Si-fei Liu ◽

Shuai-feng Lu ◽

Zhi-jun Wan ◽

Jing-yi Cheng

Keyword(s):

Cutting Force ◽

Rock Cutting ◽

Rock Breaking ◽

Pulse Number ◽

Rock Fragmentation ◽

Cutting Performance ◽

Tensile Failure ◽

Rock Damage ◽

Damage Factor ◽

Mining Machinery

Rock damage is one of the key factors in the design and model choice of mining machinery. In this paper, the influence of rock damage on rock fragmentation and cutting performance was studied using PFC 2D . In PFC 2D software, it is feasible to get rock models with different damage factors by reducing the effective modulus, tensile and shear strength of bond by using the proportional factors. A linear relationship was obtained between the proportion factor and damage factor. Furthermore, numerical simulations of rock cutting with different damage factors were carried out. The results show that with the increase of damage factor, the rock cutting failure mode changes from tensile failure to brittle failure, accompanied by the propagation of macro cracks, the formation of large debris and a notable decrease in the peak cutting force. The mean cutting force is negatively correlated with the damage factor. Besides this, the instability of cutting force was evaluated by the fluctuation index and the pulse number of unit displacement. It was found that the cutting force was quite stable when the damage factor was 0.3, which improves the reliability of cutting machines. Finally, the cutting energy consumption of rock cutting with different damage factors was analysed. The results reveal that an increase of damage factor can raise the rock cutting efficiency. The aforementioned findings play a significant role in the development of assisted rock-breaking technologies and the design of cutting head layout of mining machinery.

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Correcting Distortion of Elliptical Trajectory for Maximizing Cutting Performance in Elliptical Vibration Cutting

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.516.378 ◽

2012 ◽

Vol 516 ◽

pp. 378-383

Author(s):

Byoung Gook Loh ◽

Gi Dae Kim

Keyword(s):

Tilt Angle ◽

Relative Phase ◽

Cutting Performance ◽

Elliptical Vibration Cutting ◽

Vibration Cutting ◽

Cutting Resistance ◽

Machining Quality ◽

Elliptical Vibration ◽

Sinusoidal Input ◽

Machining Characteristics

To maximize cutting performance of elliptical vibration cutting (EVC) (also known as two-dimensional vibration assisted cutting), the elliptical trajectory of a cutting tool needs to be corrected. In this study, the effect of the shape of the elliptical trajectory on the machining characteristics of EVC is investigated. Various elliptical trajectories were created by modulating the relative phase and magnitude of the sinusoidal input voltages to the piezoelectric actuators and the effect of tilt angle of the elliptical trajectory on the machining quality such as the cutting resistance and machining quality is experimentally observed in successive micro-V grooving as the tilt angle is changed between 0o, 30o, -30o, and 90o. It is found that the tilt angle significantly affects both the cutting resistance and machining quality.

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A Method to Predict Rock Fracture with Infrared Thermography Based on Heat Diffusion Analysis

Geofluids ◽

10.1155/2021/6669016 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Nai-Fu Deng ◽

Lan Qiao ◽

Qing-wen Li ◽

Jia-Wang Hao ◽

Shan Wu

Keyword(s):

Temperature Field ◽

Infrared Radiation ◽

Direct Detection ◽

Diffusion Theory ◽

Rock Fracture ◽

Heat Diffusion ◽

Indirect Detection ◽

Rock Surface ◽

True Triaxial ◽

The Real

The forming of micro or mesocracks on rock surfaces is a symptom and precursor of the degradation of deep surrounding rocks under excavation. However, the direct detection or observation of these tiny developed cracks is not practical due to the limitation of current instruments which can only capture and recognize macrocracks. Therefore, many indirect detection ways are proposed to acquire some precautional signals and hereby forestall damage and failure of surrounding rocks. Infrared radiation (IRR) monitoring is one of the frequently used technologies. Current thermography derived from IRR can capture all temperature changes including the surrounding environment; this may influence the on-site judgement due to uncertainty or blur of generated temperature images. This paper proposes the “pseudothermography” under the true triaxial compressive test by combining the infrared radiation data and the heat diffusion theory. Our method evenly selects 25 small regions on the observed rock surface and uses the data obtained from these regions to derive the global temperature field which contains no uncertainty. By comparing our method with the real temperature field, the deduced diffusion model proposed in this paper can relatively reflect the real crack initiation under increasing loading. The experiment result proves that the attempt for the application of heat diffusion law is feasible to indirectly reflect the formation of micro and mesocracks and, ultimately, foresee the failure of the surrounding rock.

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A study on the influence of pick geometry on rock cutting based on full-scale cutting test and simulation

Advances in Mechanical Engineering ◽

10.1177/1687814020974499 ◽

2020 ◽

Vol 12 (12) ◽

pp. 168781402097449

Author(s):

Xuefeng Li

Keyword(s):

Shear Failure ◽

Cutting Parameters ◽

Rock Cutting ◽

Rake Angle ◽

Full Scale ◽

Cutting Performance ◽

Tensile Failure ◽

General Process ◽

Multiple Attribute ◽

Cutting Simulations

In this paper, series of full-scale cutting tests and cutting simulations are carried out to investigate the influence of installation parameter and geometry of the pick on cutting performance. The discrete element method is used to simulate the rock cutting process. A general process to calibrate macro properties of rock including uniaxial compressive strength (UCS), elastic modulus, Poisson’s ratio, cohesion and internal friction angle is proposed and used to complete the calibration of coal model. The cutting simulations are performed using picks with different tip angles and rake angles. The results show that the peak cutting force (PCF) decreases with the increase of rake angle following an inverse proportional function when the rake angle is positive, while it varies following a parabolic curve in the condition of negative rake angle. Moreover, the crack mode changes from primarily shear failure to primarily tensile failure with the increase of rake angle. Finally, a multiple-attribute index is proposed to evaluate the cutting performance and select the optimum cutting parameters.

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