• Title, Summary, Keyword: Rock cutting

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Complex analysis of rock cutting with consideration of rock-tool interaction using distinct element method (DEM)

  • Zhang, Guangzhe;Dang, Wengang;Herbst, Martin;Song, Zhengyang
    • Geomechanics and Engineering
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    • v.20 no.5
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    • pp.421-432
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    • 2020
  • Cutting of rocks is very common encountered in tunneling and mining during underground excavations. A deep understanding of rock-tool interaction can promote industrial applications significantly. In this paper, a distinct element method based approach, PFC3D, is adopted to simulate the rock cutting under different operation conditions (cutting velocity, depth of cut and rake angle) and with various tool geometries (tip angle, tip wear and tip shape). Simulation results showed that the cutting force and accumulated number of cracks increase with increasing cutting velocity, cut depth, tip angle and pick abrasion. The number of cracks and cutting force decrease with increasing negative rake angle and increase with increasing positive rake angle. The numerical approach can offer a better insight into the rock-tool interaction during the rock cutting process. The proposed numerical method can be used to assess the rock cuttability, to estimate the cutting performance, and to design the cutter head.

Characteristic of size distribution of rock chip produced by rock cutting with a pick cutter

  • Jeong, Hoyoung;Jeon, Seokwon
    • Geomechanics and Engineering
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    • v.15 no.3
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    • pp.811-822
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    • 2018
  • Chip size distribution can be used to evaluate the cutting efficiency and to characterize the cutting behavior of rock during cutting and fragmentation process. In this study, a series of linear cutting tests was performed to investigate the effect of cutting conditions (specifically cut spacing and penetration depth) on the production and size distribution of rock chips. Linyi sandstone from China was used in the linear cutting tests. After each run of linear cutting machine test, the rock chips were collected and their size distribution was analyzed using a sieving test and image processing. Image processing can rapidly and cost-effectively provide useful information of size distribution. Rosin-Rammer distribution pamameters, the coarseness index and the coefficients of uniformity and curvature were determined by image processing for different cutting conditions. The size of the rock chips was greatest at the optimum cut spacing, and the size distribution parameters were highly correlated with cutter forces and specific energy.

A study of diamond wire rock cutting process analysis by FEM

  • Kabir, Mohammed Ruhul;Sagong, Myung;Ahn, Sung-Kwon
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.17 no.6
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    • pp.615-621
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    • 2015
  • In this paper diamond wire cutting method has been proposed to cut the rock in the tunnel face. Diamond wire saw method could cut the rock from tunnel face with very minor vibration and noise. In this study rock cutting process has been simulated with FEM method by using LS-DYNA explicit non-linear finite element code. Normal load act as an prime factor when cutting the rock surface. For observing the effect of normal load on bead, several experiments has been conducted by varying normal loads on the bead. From each experiment, cutting rate has been calculated to compare the cutting rate with different load conditions. By increasing the normal load on bead, cutting rate increases drastically.

The investigation of rock cutting simulation based on discrete element method

  • Zhu, Xiaohua;Liu, Weiji;Lv, Yanxin
    • Geomechanics and Engineering
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    • v.13 no.6
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    • pp.977-995
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    • 2017
  • It is well accepted that rock failure mechanism influence the cutting efficiency and determination of optimum cutting parameters. In this paper, an attempt was made to research the factors that affect the failure mechanism based on discrete element method (DEM). The influences of cutting depth, hydrostatic pressure, cutting velocity, back rake angle and joint set on failure mechanism in rock-cutting are researched by PFC2D. The results show that: the ductile failure occurs at shallow cutting depths, the brittle failure occurs as the depth of cut increases beyond a threshold value. The mean cutting forces have a linear related to the cutting depth if the cutting action is dominated by the ductile mode, however, the mean cutting forces are deviate from the linear relationship while the cutting action is dominated by the brittle mode. The failure mechanism changes from brittle mode with larger chips under atmospheric conditions, to ductile mode with crushed chips under hydrostatic conditions. As the cutting velocity increases, a grow number of micro-cracks are initiated around the cutter and the volume of the chipped fragmentation is decreasing correspondingly. The crack initiates and propagates parallel to the free surface with a smaller rake angle, but with the rake angle increases, the direction of crack initiation and propagation is changed to towards the intact rock. The existence of joint set have significant influence on crack initiation and propagation, it makes the crack prone to propagate along the joint.

A review of the effects of rock properties on waterjet rock cutting performance (암석물성이 워터젯 암석절삭 성능에 미치는 영향고찰)

  • Oh, Tae-Min;Park, Eui-Seob;Cheon, Dae-Sung;Cho, Gye-Chun;Joo, Gun-Wook
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.17 no.5
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    • pp.533-551
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    • 2015
  • The rock fracturing during waterjet cutting is very complicated because rock is inhomogeneous and anisotropic, compared with artificial materials (e.g., metal or glass). Thus, it is very important to verify the effects of rock properties on waterjet rock cutting performance. Properties affecting the rock cutting efficiency have been variously described in the literature, depending on the experimental conditions (e.g., water pressure, abrasive feed rate, or standoff distance) and rock-types studied. In this study, a rock-property-related literature review was performed to determine the key properties important for waterjet rock cutting. Porosity, uniaxial compressive strength, and hardness of the rock were determined to be the key properties affecting waterjet rock cutting. The results of this analysis can provide the basic knowledge to determine the cutting efficiency of waterjet rock cutting technology for rock excavation-related construction.

Assessment of Cutting Performance of a TBM Disc Cutter for Anisotropic Rock by Linear Cutting Test (선형절삭시험에 의한 이방성 암석에 대한 TBM 디스크커터 절삭 성능 평가 연구)

  • Jeong, Ho-Young;Jeon, Seok-Won;Cho, Jung-Woo;Chang, Soo-Ho;Bae, Gyu-Jin
    • Tunnel and Underground Space
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    • v.21 no.6
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    • pp.508-517
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    • 2011
  • The linear cutting test is the most reliable and accurate approach to measuring cutting forces and cutting efficiency using full-size disc cutter in various rock types. The result of linear cutting tests can be used to obtain the key parameters of cutter-head design (i.e. optimum cutter spacing, cutter forces). In Korea, LCM (Linear Cutting Machine) tests have been performed for typical Korean rock types, but these studies focused on the isotropic rocktypes. For prediction of TBM (Tunnel Boring Machine) performances in complex geological conditions including a bedded and schistose rockmass, it is important to consider the effects of anisotropy of rockmass on cutting performances and cutting efficiency. This study discusses a series of LCM tests that were performed for Asan Gneiss having two types of anisotropy angles to assess the effect of the anisotropy angle on rock-cutting performances of TBM. The result shows that the rock-cutting performances and optimum cutting conditions are affected by anisotropy angle and the effect of anisotropy on rock strength should be considered in a prediction of the cutting performances and efficiency of TBM.

Design and Construction of Green Slope Fabric Form on Cutting Slope (절토사면의 Nailing 보강 Fabric Form의 설계와 시공)

  • 송재헌;최영근
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.81-92
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    • 2000
  • Green Slope(F.F.R : Fabric Form Reinforcement Method) is one of an environmental slope protection method at steep cutting sites. This method is that soil and rock at the steep slope is fixed using the environmental Fabric Form, Nail, Rock Bolt and Rock Anchor, And then, the surfaces covered with grasses or weeds. This method will be satisfied both safe slope protection and natural environment appearance. Green Slope is a useful method of the construction sites of steep cutting slopes.

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Fundamental Study on Rock Cutting by an Actuated Undercutting Disc (구동형 언더커팅 디스크에 의한 암석절삭에 관한 기초연구)

  • Jeong, Hoyoung;Wicaksana, Yudhidya;Kim, Sehun;Jeon, Seokwon
    • Tunnel and Underground Space
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    • v.30 no.6
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    • pp.591-602
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    • 2020
  • Several alternative rock-cutting concepts, which are modified from the conventional ones, have been developed lately. Of the concepts, undercutting is one of the latest technologies. In this study, as a fundamental study on the undercutting technique, the rock-cutting mechanism and important parameters of the undercutting were introduced. This study built up cutting test system for evaluating the cutting performance of an actuated undercutting disc cutter (ADC), and carried out a series of cutting tests under different cutting parameters of ADC. The characteristics of cutter forces obtained from ADC rock-cutting tests were analyzed. The both average and peak values of the three directional cutter forces were linearly increased with the increases of linear velocity, penetration depth in vertical direction and eccentricity of ADC.

A Study on the Revegetation Structural Analysis for Environment Factor of Road Slope (도로비탈면의 환경인자를 고려한 식생구조분석에 관한 연구)

  • Jeon, Gi-Seong
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.7 no.2
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    • pp.12-20
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    • 2004
  • This study was carried out from January 1998 to December 1999 to report the revegetation of cutting-rock slopes and a design standard in the highway cut-slopes. The field data was collected from the 67 sites cutting-rock slopes of highways, local roads, and field test. As the result of analyze, cutting-rock slopes revegetation measures were 16 types. There were Vine planting(3 types), Hydroseeding measures with seed-fertilizer-soil materials(5 types), Vegetaion-base spraying measures(5 types), and Stability measures(3 types). The factors affecting the plant coverage rates of cutting-rock slopes were the slope gradient, the slope width and direction. The plant coverage rate decreases in the condition of steep slope and long slope width and length(height). In addition, the plant coverage rates of the westward and southward were lower than that of the northward and eastward. Most dominant species were Zoysia japonica, Lespedeza cyrtobotrya, Lespedeza cuneata, Rubus crataegifolius, Miscanthus sinensis, Arrundinella hirta, Themeda triandra, and Oenothera odorata. Exotic species were Eragrostis curvula(Weeping lovegrass), Dactylis glomerata Orchardgrass), Lolium perenne(Perennial ryegrass), and Festuca arundinacea(Tall fescue). It is recommended to adjust the proposed factor as environment, topsoil, classification of rock, field condition and characteristic related with revegetation measures on slopes for the presentation of revegetation standard.

Studies on Drilling and Cutting Characteristics for Granite Rocks Using Waterjets (워터젯을 이용한 화강암 천공과 절삭 특성에 관한 연구)

  • Oh, Tae-Min;Hong, Eun-Soo;Cho, Gye-Chun
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.1338-1345
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    • 2009
  • Although rock excavation is necessary for the effective utilization of urban space, most conventional rock excavation methods, including the blasting method, cause high noise and vibration. Meanwhile, if a high pressure waterjet system is applied to excavate underground spaces in urban areas, the public grievance can be reduced by low noise and vibration. In this study, an abrasive waterjet system is designed and developed to study the influence of various performance parameters such as jet pressure, nozzle traverse speed, stand-off distance, or abrasive feed rate on waterjet excavation performance in laboratory. Using the developed waterjet system, rock drilling characteristics are identified by measuring drilling depths as a function of the jet exposure time. The drilling depth linearly increases with increasing the jet exposure time(under 60sec). Rock cutting characteristics are also obtained with various jet pressures(1600~3200kg/$cm^2$) and nozzle traverse speeds(1.9~14.1mm/s): The cutting depth is nonlinearly related to the jet pressure and traverse speed. Indeed, the cutting depth increases with an increase in the jet pressure and a decrease in the nozzle traverse speed. This trend can be explained by energy transferring/loss mechanism.

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