• Title, Summary, Keyword: 인공절리

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A Study on the Shear Behaviors of Non-Grouted and Cement Grouted Sawtoothed Artificial Joints (톱니형 인공 절리의 시멘트 그라우팅 전.후의 전단거동에 관한 연구)

  • 이영남;천병식;김대영
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.721-728
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    • 2000
  • The shear behavior of sawtoothed artificial joints grouted with cement milk was investigated in the laboratory under constant normal stress conditions. Tests were conducted on joints with asperities having inclinations of 16.7$^{\circ}$ and 26.6$^{\circ}$, compresive strengths having 15MPa and 47MPa under a given range of normal stresses varying from 0.76 to 1.91 MPa and at a free condition of pitching, rolling and dilatancy. Results show that the effect of asperities on shear strength increase is significant up to asperity height to grout thickness (t/a) ratio of 0.3∼1.0. Increase of cohesion is the main cause of shear strength increase in cement grouted sawtoothed artificial joints.

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Shear Deformation and Failure Characteristics of Rock-Concrete Discontinuities (암석-콘크리트 불연속면의 전단변형 및 파괴특성에 관한 연구)

  • 홍창우;전석원;황대진;최해문;박의섭
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.57-64
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    • 2001
  • 암석-콘크리트 불연속면의 전단변형 및 파괴특성을 규명하기 위해 상부 재료를 콘크리트로, 하부 재료를 암석으로 하는 규칙.불규칙 톱니형 시료와 인공 절리시료를 제작하여 실험실 직접전단시험을 실시하였다. 전단과정 동안 하중과 변위 외에 미소파괴음의 계수와 에너지를 측정하여 전단과정의 단계별 특징을 규명하였고 미소파괴음 음원추적을 실시하여 불연속면에서의 거칠기 파괴부분의 변화를 고찰하였다. 또한 암석 불연속면과 암석-콘크리트 불연속면의 거동을 비교하고 거칠기의 불규칙성 증가에 따른 전단거동의 변화를 관찰하였다.

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A Study on Shear Strength under Constant Normal Load Conditions by Using 3DEC (3DEC을 이용한 일정수직하중 조건에서의 전단강도에 관한 연구)

  • Noh, Young-Mok;Mun, Hong-Ju;Kim, Ki-Ho;Jang, Won-Yil
    • Tunnel and Underground Space
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    • v.24 no.1
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    • pp.46-54
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    • 2014
  • Direct shear tests have been initiated to understand the characteristics of joints which crucially affect the stability of rock mass. In this research, numerical approach in direct shear tests has been initiated using 3DEC on the basis of 3D distinct element method. Normal loads were altered in four different levels on artificial joint tests depending on the sawtooth angle and strengths on constant normal stress conditions, measuring the peak shear strength according to the direct shear tests under laboratory condition. Also results obtained from mechanical properties through laboratory test were used to perform numerical modeling, and shear strength obtained from the modeling was used to compare with laboratory direct shear test. As a result numerical analysis from distinct element method can simulate well on the shear behavior of rockmass.

A Case Study of Prediction and Analysis of Unplanned Dilution in an Underground Stoping Mine using Artificial Neural Network (인공신경망을 이용한 지하채광 확정선외 혼입 예측과 분석 사례연구)

  • Jang, Hyongdoo;Yang, Hyung-Sik
    • Tunnel and Underground Space
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    • v.24 no.4
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    • pp.282-288
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    • 2014
  • Stoping method has been acknowledged as one of the typical metalliferous underground mining methods. Notwithstanding with the popularity of the method, the majority of stoping mines are suffering from excessive unplanned dilution which often becomes as the main cause of mine closure. Thus a reliable unplanned dilution management system is imperatively needed. In this study, reliable unplanned dilution prediction system is introduced by adopting artificial neural network (ANN) based on data investigated from one underground stoping mine in Western Australia. In addition, contributions of input parameters were analysed by connection weight algorithm (CWA). To validate the reliability of the proposed ANN, correlation coefficient (R) was calculated in the training and test stage which shown relatively high correlation of 0.9641 in training and 0.7933 in test stage. As results of CWA application, BHL (Length of blast hole) and SFJ (Safety factor of Joint orientation) show comparatively high contribution of 18.78% and 19.77% which imply that these are somewhat critical influential parameter of unplanned dilution.

A Study of Roughness Measurement of Rock Discontinuities Using a Confocal Laser Scanning Microscope (콘포컬 레이저 현미경을 이용한 불연속면의 거칠기 측정 연구)

  • Byung Gon Chae;Jae Yong Song;Gyo Cheol Jeong
    • The Journal of Engineering Geology
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    • v.12 no.4
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    • pp.405-419
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    • 2002
  • Fracture roughness of rock specimens is observed by a new confocal laser scanning microscope (CLSM; Olympus OLS1100). The wave length of laser is 488 nm, and the laser scanning is managed by a light polarization method using two galvano-meter scanner mirrors. The function of laser reflection auto-focusing enables us to measure line data fast and precisely. The system improves resolution in the light axis (namely z) direction because of the confocal optics. Using the CLSM, it is Possible to measure a specimen of the size up to $10{\;}{\times}{\;}10{\;}cm$ which is fixed on a specially designed stage. A sampling is managed in a spacing $2.5{\;}\mu\textrm{m}$ along x and y directions. The highest measurement resolution of z direction is $10{\;}\mu\textrm{m}$, which is more accurate than other methods. Core specimens of coarse and fine grained granite are provided. Fractures are artificially maneuvered by a Brazilian test method. Measurements are performed along three scan lines on each fracture surface. The measured data are represented as 2-D and 3-D digital images showing detailed features of roughness. Line profiles of the coarse granites represent more frequent change of undulation than those of the fine granite. Spectral analyses by the fast Fourier transform (FFT) are performed to characterize the roughness data quantitatively and to identify influential frequency of roughness. The FFT results suggest that a specimen loaded by large and low frequency energy tends to have high values of undulation change and large wave length of fracture roughness.

A simple screening technique for blast resistant mutants from the radiation irradiated rice populations (도열병저항성 변이계통의 선발을 위한 인공접종법)

  • Shin-Han Kwon;Jeong-Hae Oh;Hi-Sup Song
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.15
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    • pp.141-143
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    • 1974
  • An attempt was made to develop a simple testing method fro blast resistance in the aged rice plant grown under the paddy field conditions. The blast resistance was tested with the detached 3rd leaves from the top of the plant, which were inoculated by dropping blast spore suspension mixed with 1% Tween 20 on the punched area and kept in 1% sucrose solution. The blast reaction was measured ten days after incubation at 26-28$^{\circ}C$ under highly humid conditions. With this method blast resistant lines were effectively identified and the cost of testing was cheap as compared with any other methods ever practiced.

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A Wave Propagation Analysis in the Layered Systems (적층계(積層係)를 통과하는 소성응력파(塑性應力波)의 전파(傳波))

  • Lee, Sang Ho;Ahn, Byoung Ki;Kang, Young Goo
    • Journal of The Korean Society of Civil Engineers
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    • v.13 no.2
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    • pp.61-71
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    • 1993
  • The stress waves generated by the mechanical energies by impact or the chemical energies by the explosions are transmitted through medium. The wave propagation process through medium is a very complicated procedure due to the reflections and refractions of the waves at the free surfaces and interfaces. In this study the pressure independent Von-Mises model is employed for the wave propagation analysis in the layered systems. Governing equations of this study are conservation equations of momentum and mass in Lagrangian coordinate system which is fixed to the material. Due to the shock-front which violates the continuity assumptions inherent in the differential equations numerical artificial viscosity is used to spread the shock front over several computational zones. These equations are solved by Finite Difference Method with discretized time and space coordinates. The associate normality flow rule as a plastic theory is implemented to find the plastic strains.

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A Study on the Landscape Interpretation of Songge Byeoleop(Korean Villa) Garden at Jogyedong, Mt. Bukhansan near Seoul for the Restoration (북한산 조계동 송계별업(松溪別業) 정원 복원을 위한 경관해석)

  • Rho, Jae-Hyun;Song, Suk-Ho;Jo, Jang-Bin;Sim, Woo-Kyung
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.36 no.4
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    • pp.1-17
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    • 2018
  • This study was conducted to interpret the landscape of Songge Byeoleop(Korean villa) garden at Jogyedong, Bukhansan near Seoul which was built in the mid 17C. to restore through the literature reviews and field surveys. The results were as follows; Songge Byeoleop garden was a royal villa, constructed at King Injo24(1646) of Joseon dynasty by prince Inpyeong(麟坪大君), Lee, Yo(李?, 1622~1658), the third son of King Injo who was a brother of King Hyojong. It was a royal villa, Seokyang-lu under Mt. Taracsan of Gyendeokbang, about 7km away in the straight line from main building. It was considered that the building system was a very gorgeous with timber coloring because of owner's special situation who was called the great prince. The place of Songge Byeoleop identity and key landscape of the place were consisted with Gucheon waterfall and the sound of the water with multi-layered waterfall which might be comparable to the waterfall of Yeosan in China. After the destruction of the building, the place was used for the royal tomb quarry, but there was a mark stone for forbidden quarry. The Inner part of Songge Beoleop, centered with Jogedongcheon, Chogye-dong, composted beautifully with the natural sceneries of Gucheon waterfall, Handam and Changbeok, and artificial structures, such as Bihong-bridge, Boheogak, Yeonghyudang and Gyedang. In addition, the existing Chinese characters, 'Songge Beoleop' and 'Gucheoneunpog' carved in the rocks are literary languages and place markings symbolizing with the contrast of the different forests and territories. They gave the names of scenery to the rock and gave meaning to them. Particularly, Gucheon waterfall which served as a visual terminal point, is a cascade type with multi-staged waterfall. and the lower part shows the topographical characteristics of the Horse Bowl-shaped jointed with port-holes. On the other hand, the outer part is divided into the spaces for the main entrance gate, a hanging bridge character, a bridge connecting the inside and the outside, and Yeonghyudang part for the purpose of living. Also in the Boheogak area, dual view frame structures are made to allow the view of the four sides including the width and the perimeter of the villa. In addition, at the view point in Bihong-bridge, the Gucheon water fall divides between the sacred and profane, and crosses the Bihong-bridge and climbs to the subterranean level.