• Title/Summary/Keyword: Inclined ground

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An Analytical Study on the Embedded Depth of Concrete Poles in Inclined ground (경사지에서 콘크리트 전주의 근입깊이에 대한 해석적 연구)

  • Yoon, Ki-Yong;Kim, Eung-Seok;Lee, Seung-Hyun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.2
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    • pp.1164-1169
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    • 2014
  • Overturning of concrete poles are occurred annually due to natural disaster such as a typhoon. The present code for the resisting moment and the safety on overturning of concrete poles in inclined ground is inadequate. In this study, the concept of the code for those in flat ground is applied to calculate the resisting moment in inclined ground using general analysis program L-Pile Plus13.8. According to the analytical results, the resisting moment in inclined ground is rapidly decrease as increasing the slope angle although the embedded depth are added by the additional embedded depth on the code. It is revealed that the capacity in inclined ground is equivalent to that in flat ground if additional embedded depth is increased from 1.5 to 3 times.

Expansion of Terzaghi Arching Formula to Consider an Arbitrarily Inclined Sliding Surface and Examination of its Effect

  • Son, Moorak
    • Journal of the Korean GEO-environmental Society
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    • v.17 no.7
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    • pp.27-33
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    • 2016
  • This study expanded Terzaghi arching formula, which assumed a vertical surface as a sliding surface, to consider an arbitrarily inclined surface as a sliding surface and examined the effect of a sliding surface. This study firstly developed a formula to expand the existing Terzaghi arching formula to consider an inclined surface as well as a vertical surface as a sliding surface under the downward movement of a trap door. Using the expanded formula, the effect of excavation, ground, and surcharge conditions on a vertical stress was examined and the results were compared with them from Terzaghi arching formula. The comparison indicated that the induced vertical stress was highly affected by the angle of an inclined sliding surface and the degree of influence depended on the excavation, ground, and surcharge conditions. It is expected that the results from this study would provide a better understanding of various arching phenomenon in the future.

A Study on Tunnel Loads in an Unconsolidated Ground with Inclined Layers (지층이 경사진 미고결 층상지반에서의 터널 작용토압에 관한 연구)

  • Park, Si Hyun;Kim, Young Su
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.4C
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    • pp.275-282
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    • 2006
  • Since tunnels are linear type structures that have a long extent in comparison to their excavation or inner section, tunnels must be constructed in various ground conditions. In this study, laboratory model tests and theoretical analysis on a tunnel loads are carried out in the unconsolidated ground with inclined layers for tunnel excavation. Laboratory model tests are performed with the variation in the angle of the inclined layers and tunnel depth for the model ground with inclined layers. As for the ground materials, two dimensional model ground is prepared with aluminum rods and blocks with no cohesion, which are frictional resistance free between testing apparatus walls and ground materials, by establishing the ground materials self-supporting. Moreover tunnel load equation are newly induced so that comparisons between model test results and the theoretical results are conducted as well.

Numerical Studies for Application of the SASW Method in an Inclined Soil Layer (경사지반에서 SASW기법 적용시 수치해석을 이용한 영향요소 연구)

  • 김동수
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2001.04a
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    • pp.108-119
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    • 2001
  • The Spectral Analysis of surface Waves(SASW) Method has a great has a great potential for rapid determination of shear wave velocity profile of ground. However, it has an inherent limitation in the interpretation of test results due to the assumption that the ground is layered horizontally. The reason of the assumption is that difficulties exist in obtaining analytical solutions of wave equation when a soil system is composed of inclined soil layer. In this study, a finite-element method has been employed to assess the effects of dip angle and stiffness contrast of inclined soil layers and the testing direction on the dispersion curve. The propagation of wave front in the inclined soil layer was also investigated. The results indicated that the influence of dip angle on the dispersion curve is getting obvious as the dip angle increases and the propagation of wave front in the inclined layer also entirely different compared with the case of the horizontal layer.

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A Study on the Group Effect of the Inclined Ground Anchor (경사 지반앵커의 군효과에 대한 연구)

  • 임종철;홍석우
    • Geotechnical Engineering
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    • v.10 no.4
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    • pp.39-52
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    • 1994
  • The group effect of inclined ground anchor should be considered in design, but it has been hardly studied due to the difficulties of experimental or theoretical study. In this study, the model tests for the inclined ground anchors are made, and the displacements and strain fields of ground around anchor surface are analysed. As the results of this study, the group effect of the inclined ground anchor in air dried sand ground does not show even though two anchor surfaces are very close(10.7cm, surface to surface). That is to say, ,in the case that the final failure surface by pullout of anchor shows on the anchor surface, the pullout resistances of single anchors are almost same as those of the group anchors in these model tests.

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Measurement of Unsteady Loading Noise from Hovering Rotor with Partially Inclined Ground (국부적으로 기울어진 지면을 고려한 제자리비행 로터의 비정상 하중 소음 측정)

  • Jang, Ji-Sung;Lee, Yong-Woo;Lee, Duck-Joo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.04a
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    • pp.140-143
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    • 2008
  • Experiments are performed to consider the ground effects on unsteady loading and acoustic generation. Partially inclined plate is used to maximize the unsteadiness of the rotor. Indirect method to recognize the unsteady effect is used by measuring the noise in the normal direction from the rotor plane. The experiment is conducted with a square plate of about $9m^2$ and one half of the plate is placed parallel with the rotor plane and the other half is inclined. The height of the plate and the angle of the inclined plate can be changed. Helicopter noise is also measured at the 4 different positions to study the directivity of the rotor noise. The distance between microphone and rotor hub is 1.3m. Tonal noise and broad band noise are measured and analyzed. Thickness noise, steady loading noise and unsteady loading noise are investigated from the rotor noise measurement.

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A Study on Stress Redistribution Mechanism for Tunneling in an Unconsolidated Ground with Inclined Layers (미고결 층상지반에서 터널굴착시 응력재분배 메커니즘에 관한 연구)

  • Park, Si Hyun;Ahn, Sang Ro
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.1C
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    • pp.53-61
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    • 2006
  • This study is aimed at to examine the stress redistribution mechanism for tunneling in an unconsolidated ground with inclined layers through model tests. To make the unconsolidated ground, two dimensional model ground is prepared with aluminum rods and blocks, which are frictional resistance free between testing apparatus walls and ground materials, by establishing the ground materials self-supporting. It is carried out to measure the ground deformation and the stress redistribution for model ground with tunneling by measuring apparatus respectively. For the ground deformation, surface settlements are measured to examine the deformation features during tunnel excavation. For the stress redistribution, the earth pressure acting on both the tunneling part and its surrounding parts is measured to examine their mutual relationship. Based on test results, precise examination is conducted on the stress redistribution mechanism in the unconsolidated ground with inclined layers during tunnel construction.

Derivation of a 3D Arching Formula for Tunnel Excavation in Anisotropic Ground Conditions and Examination of Its Effects (비등방 지반에서 터널굴착을 위한 3차원 아칭식의 유도 및 그 영향 조사)

  • Son, Moorak
    • Journal of the Korean Geotechnical Society
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    • v.34 no.12
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    • pp.19-27
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    • 2018
  • Terzaghi proposed a 2D formula for arching based on the assumption of a vertical sliding surface induced in the upper part due to the downward movement of a trapdoor. The formula was later expanded to consider 3D tunnel excavation conditions under inclined sliding surfaces. This study further extends the expanded formula to consider the effects of different ground properties and inclined sliding conditions in the transverse and longitudinal directions considering anisotropic ground conditions, as well as 3D tunnel excavation conditions. The 3D formula proposed in this study was examined of the induced vertical stress under various conditions (ground property, inclined sliding surface, excavation condition, surcharge pressure, earth pressure coefficient) and compared with the 2D Terzaghi formula. The examination indicated that the induced vertical stress increased as the excavation width and length increased, the inclination angle increased, the cohesion and friction angle decreased, the earth pressure coefficient decreased, and the surcharge pressure increased. Under the conditions examined, the stress was more affected at low excavation lengths and by the ground properties in the transverse direction. In addition, The comparison with the 2D Terzaghi formula showed that the induced vertical stress was lower and the difference was highly affected by the ground properties, inclined sliding conditions, and 3D tunnel excavation conditions. The proposed 3D arching formula could help to provide better understanding of complex arching phenomena in tunnel construction.

Analysis of Factors Influencing the Measurement Error of Ground-based LiDAR (지상기반 라이다의 측정 오차에 영향을 미치는 요인 분석)

  • Kang, Dong-Bum;Huh, Jong-Chul;Ko, Kyung-Nam
    • Journal of the Korean Solar Energy Society
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    • v.37 no.6
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    • pp.25-37
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    • 2017
  • A study on factors influencing measurement error of Ground-based LiDAR(Light Detection And Ranging) system was conducted in Kimnyeong wind turbine test site on Jeju Island. Three properties of wind including inclined angle, turbulence intensity and power law exponent were taken into account as factors influencing the measurement error of Ground-based LiDAR. In order to calculate LiDAR measurements error, 2.5-month wind speed data collected from LiDAR (WindCube v2) were compared with concurrent data from the anemometer on a nearby 120m-high meteorological mast. In addition, data filtering was performed and its filtering criteria was based on the findings at previous researches. As a result, at 100m above ground level, absolute LiDAR error rate with absolute inclined angle showed 4.58~13.40% and 0.77 of the coefficients of determination, $R^2$. That with turbulence intensity showed 3.58~23.94% and 0.93 of $R^2$ while that with power law exponent showed 4.71~9.53% and 0.41 of $R^2$. Therefore, it was confirmed that the LiDAR measurement error was highly affected by inclined angle and turbulence intensity, while that did not much depend on power law exponent.

Numerical analysis of deep excavation in layered and asymmetric ground conditions (흙막이 굴착 시 지층 경사의 영향에 대한 수치해석적 분석)

  • Shin, Jong-Ho;Kim, Hak-Moon;Kim, Sang-Hwan;Kim, Sang-Kil;Nam, Taek-Soo
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.03a
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    • pp.1260-1268
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    • 2008
  • In case of deep excavation analysis, the theory of beam on elasto-plastic geo-material (elasto-plastic theory) can not consider the inclined ground layers appropriately. It is frequently assumed that the soil layers are parallel to the surface. However, the soil layers are generally inclined and even asymmetric. The common modelling of the asymmetric half section of the excavation system using the elasto-plastic theory, can lead differences from the real behaviour of ground, which has critical significance in case of deep excavation in urban area. In this study, an attempt to find appropriate modelling methods was made by carrying out a comparative study between the FEM and the elasto-plastic analyses. It is shown that in case of the upward-inclined soil profile the elasto-plastic theory may underestimate the performance of retaining structures.

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