• Title/Summary/Keyword: 굴착 비트

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A Study on Shape Optimization of Impregnated Bit (Impregnated Bit의 형상 최적화에 관한 연구)

  • Youm, Kwang-Wook
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.6
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    • pp.60-66
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    • 2021
  • The core is extracted through drilling and used to evaluate the feasibility of developing mineral resources. To extract the core, a bit is installed in the forefront of the drilling device for drilling. Here, the drill bit receives stress due to direct friction against the ground. In addition, a bit appropriate for the given ground condition should be used due to the possibility of damaging a bit as a result of friction. This paper used a current bit model based on an impregnated bit and analyzed a new bit model that uses a stiffener of similar/disparate materials. The hardness and deflective strength were then evaluated by modeling the shape of impregnated bit through a calculation based on a theoretical formula. Through FEM analysis of the existing model and the new model, the stress and strain calculation results were optimized to minimize the stress and strain with a stress of 1.92 × 107 Pa and a strain of 9.6× 10-5 m/m.

A Study on Notch Bit System for Controlling Blast Vibration and Over-break in Rock Mass (발파공해 해소 및 여굴 최소화를 위한 선균열 암굴착 노치장비 개발에 관한 연구)

  • Jeong, Dong-Ho;Moon, Sang-Jo;An, Dae-Jin;Jeong, Won-Joon;Kim, Eun-Kwan;Kim, Dong-Gyou
    • Tunnel and Underground Space
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    • v.17 no.3 s.68
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    • pp.216-224
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    • 2007
  • Blasting, using shock and dynamic energy of explosive, is very effective tunnel excavation method. But it had serious problem which is the blast vibration and over-break. In recent study, pre-cracked excavation method using notch hole reduced blast vibration and over-break in tunnel, so we performed study about developing notch bit system for making notch hole. In order to make notch hole effectively we had perform drilling experiments changing length and height of notch and in order to improve speed and precision of drilling we had developed notch bit system which consists of drilling bit, notch bit, adapter and notch guide.

Correlation Between Drilling Parameter and Tunnel Support Pattern Using Jumbo Drill (도로터널에서 지보패턴별 굴착지수 상관관계 고찰)

  • Kim, Nag-Young;Kim, Sung-Hwan;Chung, Hyung-Sik
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.3 no.4
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    • pp.17-24
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    • 2001
  • Four road tunnels of which the construction conditions were similar were selected in the paper, and laboratory tests and rockmass classification for the tunnels were carried out. And the analysis was performed to find out the correlation between ratio of bit abrasion or drilling parameter and support pattern of tunnel using jumbo drill machine. It was analyzed that there was average abrasion of bit from 11.85% to 3.25% per support patterns of tunnel in four tunnels. Drilling parameter happens to fluctuate according to extent of fracture zone.

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A Study for Predicting Rotational Cutting Torque from Electrical Energy Required for Ground Drilling (지반절삭 전기에너지를 활용한 회전굴착토크 예측에 관한 연구)

  • Choi, Chang-Ho;Cho, Jin-Woo;Lee, Yong-Soo;Chung, Ha-Ik;Park, Yong-Boo
    • Journal of the Korean Geotechnical Society
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    • v.23 no.7
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    • pp.57-64
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    • 2007
  • This study proposes a method to estimate drilling torque during ground boring with an aid of electrical energy required for rotating a boring-auger. Ground boring is commonly used in geotechnical engineering such as preboring precast pile installation, soil-cement grouting, ground exploration and so forth. In order to understand the correlation between required electrical energy to rotate the boring auger and the drilling torque, a small laboratory apparatus was designed and a pilot study was performed. The apparatus rotates common drill bits of $D=5{\sim}25mm$ in CBR specimens. The velocity of a bit is 19 RPM and predefined using a reduction gear which connects a main rotation axis to a 25 Watts AC electrical motor shaft. In the middle of drilling the motor current increments and the drilling torque were measured and the correlation between the current and the torque was obtained through linear square fits. Based on the correlation the acquired motor current during drilling was applied to predict the drilling torque in consequent testing and the prediction results were compared to the measured torque. The comparison leads a conclusion that the motor current during drilling using electrical power may be a good indicator to estimate/determine strength characteristics of the ground.

Technical Trends and Patent Analysis for Reaming Bits (확공비트의 기술동향 및 특허분석)

  • Min, Kyung-Nam;Jung, Chan-Muk;Kim, Gyui-Woong
    • The Journal of Engineering Geology
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    • v.23 no.2
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    • pp.127-136
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    • 2013
  • We analyzed the patent trends for whole drilling bits to reveal the main R&D directions, focusing on patents applied for and registered in Korea, the USA, Japan, and Europe. The technology was classified into two groups as a primary classification step (reaming systems and fixed systems), and into seven groups as a secondary classification step (sliding, odex, horizontal pivot, vertical pivot, concentric, eccentric, and etc.). A total of 33,614 patents were retrieved and 870 patents were selected for final effective analysis by data deduplication and filtering. A portfolio analysis using the correlation between the number of patents and the applicants for each patents revealed a sliding system as the key technology with greatest growth potential. From an analysis of the barriers to patents being granted, we emphasize the need to avoid similar topics existing patents or patent applications and to develop differential technology.

Development of a trench shield machine for the near-surface railway construction (저심도 철도 건설을 위한 트렌치 쉴드 장비 개발연구)

  • Lee, So-Oh;Sagong, Myung;Kim, Sang-Hwan
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.17 no.2
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    • pp.175-187
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    • 2015
  • In this paper, the development of trench shield machine for near-surface railway construction were presented. The Near-surface railway can be constructed by cut and cover construction method, because it is installed at the depth of 5~7 m below roads. The cut and cover construction method mostly use temporary supports. The limitation of the cut and cover method is high installation cost and long construction period. To overcome these disadvantages, development of the trench shield machine is proposed and expected to shorten the construction time and cost of near-surface railway system. The sliding retaining wall of trench shield equipment replaces the role of temporary support (solider piles and lagging) and excavator equiped to the bottom front of the machine shorten the excavation time. This paper deals with design of the bit attached to the excavator and required capacity of the motor.

A study on the damage of cutter bit due to the rotation speed of shield TBM cutter head in mixed ground (복합지반에서의 쉴드 TBM 커터헤드의 회전속도에 따른 커터비트 손상에 관한 실험적 연구)

  • Kang, Eun-Mo;Kim, Yong-Min;Hwang, In-Jun;Kim, Sang-Hwan
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.17 no.3
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    • pp.403-413
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    • 2015
  • This paper presents the cutter bit damage due to the rotation speed of shield TBM cutter head in the mixed ground. The efficient of cutter bits and disk cutter are very important for tunnelling in mixed ground. In particular, this research is focused on the performance of cutter bits during excavation in mixed ground which is consist of the weathered soil and rock formation. In order to carry out this research, the experimental works are prepared performed by using the scaled shield TBM cutter bits evaluation machine developed. The mixed ground is prepared considering with a scale effect of tunnel size. Three different rotation speeds of shield TBM cutter head (i.e. 2, 3, 4 rpm) are applied in the experimental work. The drag forces acting on the cutter bits are measured at each cutter bit during rotation of cutter head. It is also analysed the variation of drag forces due to the rotation speed of shield TBM cutter head. The results of this research are clearly shown that the drag forces acting on the cutter bits are jumped up at the boundary between weathered soil and rock. It is also indicated that the jamping drag forces are increased with increasing the rotation speed of the cutter head. It is found from the research that the higher rotation speed of shield TBM cutter head will be high risk in the mixed ground. It is, therefore, suggested that the use of lower rotation speed of shield TBM cutter head is recommended for reducing the cutter bit damage in practice.

A Study on the Arrangement Design of Shield-TBM Cutter Bit (Shield-TBM 커터비트배치 설계에 관한 연구)

  • Kim, Sang-Hwan;Kim, Ji-Tae;Lim, Chae-Ho
    • Journal of the Korean Geotechnical Society
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    • v.28 no.5
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    • pp.67-76
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    • 2012
  • This study is a research about cutter bits arrangement of shield-TBM and carried out a scale model test and numerical analysis according to a space of cutter bits. A cutter head pressures and an advance time are measured to be followed by the space of cutter bits with an advance speed through the scale model test. We conducted the numerical analysis to verify the result of the scale model test, and to compare with the scale model test. There are three cases of space : unification 1.0D and 1.5D. In case TBM is excavated and space is 1.0D, the advance speed is much faster than the other cases, and pressure of face of ground deformation and cutter head is maintained stably. If additional researches about bits arrangement of cutter head of sand ground based on the result of this research are performed, substantial results may be obtained.

A study on the excavation rate of directional drilling using finite element method (유한요소법을 이용한 방향성 시추의 굴진율 연구)

  • Jung, Tae Joon;Shin, Younggy
    • Plant Journal
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    • v.17 no.3
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    • pp.42-46
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    • 2021
  • The equation of motion of the drill string along the excavation trajectory was analyzed using the Lagrangian approach together with the finite element method (FEM). A drill string of circular cross section is constructed by combining a plurality of circular axes each having 12 degrees of freedom (DOF). FEM analysis can observe the vibration and dynamic changes of the entire drill string, and it is easy to apply comprehensive boundary conditions to reproduce the simulation of a realistic drill string. In this study, the constructed FEM motel was simulated. In order to apply the FEM program to the actual drill trajectory, the dynamic analysis of the curved beam was verified by comparison with the actual values. The dynamic change over time was observed.

Optimization of Flow Path of Drill Bit Using CFD Simulation (CFD를 이용한 굴착용 천공드릴비트의 유로 최적화에 관한 연구)

  • Song, Chang-Heon;Kwon, Ki-Beom;Park, Jin-Young;Shin, Dae-Young;Cho, Jung-Woo
    • Tunnel and Underground Space
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    • v.22 no.4
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    • pp.257-265
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    • 2012
  • In this study, a series of CFD (Computational Fluid Dynamics) simulations carried out to evaluate the optimum design model of the internal flow path of drill bit. The Star-CCM+ code was adopted to simulate the multi-phase discharge flow of rock particles and flushing air during a drilling process. The input parameters for the flow simulation of rock particles and air were obtained from the in-situ drilling test results. After the three design factors were determined, the experimental design method (Taguchi method) was utilized to evaluate the optimum value of each factor.