• 제목, 요약, 키워드: Ground investigation

검색결과 910건 처리시간 0.041초

A shake table investigation on interaction between buildings in a row

  • Khatiwada, Sushil;Chouw, Nawawi
    • Coupled systems mechanics
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    • v.2 no.2
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    • pp.175-190
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    • 2013
  • Pounding damage has been observed frequently in major earthquakes in the form of aesthetic, minor or major structural cracks and collapse of buildings. Studies have identified a building located at one end of a row of buildings as very vulnerable to pounding damage, while buildings in the interior of the same row are assumed to be safer. This study presents the results of a shake table investigation of pounding between two and three buildings in a row. Two steel portal frames, one stiffer and another more flexible, were subjected to pounding against a frame with eight other configurations. Three pounding arrangements were considered, i.e., the reference frame (1) on the right of the second frame, (2) in the middle of two identical frames, and (3) on the right of two identical frames. Zero seismic gap was adopted for all tests. Five different ground motions are applied from both directions (right to left and left to right). The amplification of the maximum deflection due to pounding was calculated for each configuration. The results showed that, for the stiffer building in a row, row building pounding is more hazardous than pounding between only two buildings. The location of the stiffer frame, whether at the end or the middle of the row, did not have much effect on the degree of amplification observed. Additionally, for all cases considered, pounding caused less amplification for stronger ground motions, i.e., the ground motions that produced higher maximum deflection without pounding than other ground motions.

Field and laboratory assessment of ground subsidence induced by underground cavity under the sewer pipe

  • Kong, Suk-Min;Kim, Dong-Min;Lee, Dae-Young;Jung, Hyuk-Sang;Lee, Yong-Joo
    • Geomechanics and Engineering
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    • v.16 no.3
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    • pp.285-293
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    • 2018
  • In densely populated urban areas with a large amount of infrastructure, ground subsidence events can result in massive casualties and economic losses. In South Korea, the incidence of ground subsidence in urban areas has increased in recent years and the number of underground cavities suspected of causing such events has significantly increased. Therefore, it is essential to develop techniques to prevent the occurrence of underground and ground subsidence. In this study, a field test, laboratory test, and numerical analysis were conducted to determine the optimal compaction degree of the upper support layer of any underground cavity below the level of sewer pipes in order to prevent such cavities from collapsing and leading to ground subsidence accidents. During the field test, an underground cavity was simulated using ice, and the generation of the cavity was confirmed using ground penetrating radar. The ground investigation was performed using a cone penetration test, and the compaction of the ground where ground subsidence occurred was evaluated with a laboratory test. The behaviour of the ground under various conditions was predicted using a numerical analysis based on the data obtained from the field test and previous studies. Based on these results, the optimal compaction degree of the ground required to prevent the underground cavity from causing ground subsidence was predicted and presented.

Near Field 지진의 특징과 구조응답에 대한 영향 (Characteristics of Near Field Earthquakes and its effect on Seismic demands)

  • 배미혜;권오성;한상환
    • 한국전산구조공학회:학술대회논문집
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    • pp.208-213
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    • 2002
  • Near field ground motions contain distinct, large amplitude pulses in both velocity and displacement. This paper presents an investigation on the characteristics of near filed earthquakes and their effects on seismic demands. For this purpose 20 sets of near field ground motion and 20 sets of far filed ground motion are compared with respect to Linear Elastic Response Spectrum(LERS), Response Modification Factor(R), Inelastic Response Spectrum(IRS), and performance point of Capacity Spectum Method(CSM).

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영상사진을 이용한 지반공학적인 선구조분석 연구 (A Study on Geotechnical Lineament Analysis by Image Processing Method)

  • 이수곤;금동헌
    • 한국지반공학회:학술대회논문집
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    • pp.593-600
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    • 2000
  • Most of ground investigations can be grasped geological distribution which like rock name, geological structure, soil condition, underwater condition, land slide, ground cave-in, ground collapse by geological survey. But geological survey is limited to part region geological structure, not wide region. Therefore, Image Processing Method must need to grasp wide region geological structure. The object of this research is presented analysis data of geotechnical engineering in first step investigation.

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Practical investigation of a monopod fabrication method and the numerical investigation of its up-righting process

  • Hafez, Khaled A.;Ismael, Maged M.
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.5 no.3
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    • pp.431-453
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    • 2013
  • The principal purpose of this paper is to present a novel two phases rational scenario applied in constructing an offshore monopod platform; in which the two phases are the all-ground horizontal construction phase and the post-construction phase. Concerning the all-ground construction phase, a brief investigation of its different stages, i.e., pre-fabrication, fabrication, pre-assembling, positioning, assembling, and surface finishing is introduced. The important practical aspects of such construction phase are investigated without going into the nitty-gritty of the details involved therein. Concerning the post-construction phase, a clear investigation of its sequential stages, i.e., lifting, moving and up-righting is introduced. A finite element model (FEM) of the monopod platform is created to perform the structural analysis necessary to decide the suspension points/devices and the handling scenario during the various stages of the post-construction phase on a rational wise. Such structural analysis is performed within the framework of the three dimensional quasi-static modeling and analysis aiming at simulating the realistic handling condition, and hence introducing a reliable physical interpretation of the numerical results. For the whole effort to be demonstrated efficiently, the results obtained are analyzed, the conclusions are presented, and few related recommendations are suggested.

근접시공에 대한 수로터널 지반조사 및 안정성 분석 (Site Investigation and stability analysis for water tunnel being neighboring construction)

  • 전제성;김기영;이상덕;김두준
    • 한국지반공학회:학술대회논문집
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    • pp.550-555
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    • 2005
  • In vicinity of Seoul, there has been water service tunnel that classified into 1st grade facility by special act for the safety control of public structures and with providing capacity equals to $1,543{\times}10^3$(ton/day) and inner pressure equals to $2.5-3.5kg/cm^2$. In this research, site investigation and stability analysis for water tunnel caused by new construction of road tunnel were carried out. the ground near water tunnel were zoned into spatial area having similar geotechnical characteristics and estimating geotechnical properties for each area. The site for analysis consists of banded biotite gneiss, biotite schist and granite gneiss with spatial non-homogeneity, and for that reason weathering and fault zone were distributed with large scale. It's important thing to consider spatial ground zone and their geotechnical properties properly into stability analysis at design and construction stage. Also, using results of site investigation, stability of existing tunnel have been analyzed for Hydraulic Fracture/Jacking and deformation in detail.

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지반 응답 해석 Round Robin Test의 입력 지진파 및 물성에 관한 고찰 (Investigation into the Input Earthquake Motions and Properties for Round Robin Test on Ground Response Analysis)

  • 선창국;한진태;최정인;김기석;김명모
    • 한국지반공학회:학술대회논문집
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    • pp.266-292
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    • 2007
  • Round Robin Test (RRT) on ground response analyses was conducted for three sites in Korea based on several site investigation data, which include borehole logs with the N values from standard penetration test (SPT) for all three sites and additionally cone tip resistance profiles for two sites. Three input earthquake motions together with the site investigation data were provided for the RRT. A total of 12 teams participating in this RRT presented the results of ground response analyses using equivalent-linear and/or nonlinear method. Each team determined input geotechnical properties by using empirical relationships and literatures based on own judgment, with the exception of the input motions. Herein, the characteristics of input motions were compared in terms of the frequency and period, and the selection of the depth to bedrock, on which the motions is impinged, was discussed considering geologic conditions in Korea. Furthermore, a variety of geotechnical properties such as shear wave velocity profiles and soil nonlinear curves were investigated with the input properties used in this RRT.

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중부지방 상록지피식물의 조경적 이용 -광이 월동중의 엽색에 미치는 영향을 중심으로- (Utilization of Evergreen Ground Covers in Central Region of Korea as Landscape Materials -Focusing on the Changes in Leaf Color Related with Light during Winter-)

  • 남유경;김명회
    • 농업생명과학연구
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    • v.45 no.2
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    • pp.1-7
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    • 2011
  • 본 연구는 중부지방에서 동절기간에 적용 가능한 상록지피식물의 이용을 확대하기 위하여 서로 다른 광조건에서의 생장변화를 조사하였다. Nandina domestica는 동절기 동안 광조건에 관계없이 음지에서 높은 엽록소값을 나타냈다. 이후 4월에는 서울의 반포지역에서 엽록소 값이 광조건에 따른 차이는 나타나지 않았으나 북풍에 노출되어 있는 과천지역에서는 양지에서 현저히 감소하였으며 잎이 모두 낙엽 되었다. Ophiopogon japonicus는 지역에 관계없이 2월에 양지보다 음지에서 엽록소값이 두 배 이상의 높은 값을 나타냈으며 L과 b값도 조사기간 동안 음지조건에서 높게 나타났다. 4월에는 반포지역에서 광조건에 따른 차이가 없었으나 과천지역에서는 양지에서 동절기 동안 엽색이 탈색되었다. Pachysandra terminalis는 조사지역과 기간에 관계없이 음지조건에서 엽록소값과 L, b값이 높게 나타났다. 따라서 중부지방에서 상록지피식물을 이용하기 위해서는 음지조건의 조성이 필요할 것으로 여겨진다.

터널 시공 중 지반 관련 사고 사례의 원인 분석과 지반 조사 결과의 활용에 관한 검토 (Case Study on the Tunnel Collapses during the Construction and Application of Geotechnical Investigation)

  • 박남서;이치문;강상호
    • 한국지반공학회:학술대회논문집
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    • pp.47-60
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    • 1998
  • 본 고에서는 지반 조건의 불균질성 및 이방성에 기인하는 사전 지반 조사의 한계성, 혹은 충분치 못한 사전 지반 조사에 의해 터널 시공 중 발생되었던 터널 사고 사례들을 검토, 분석하고 지반 조사의 터럴 설계 및 시공에서의 활용에 대하여 고찰하였다. 본문에서는 암석(intact rock) 자체는 양호할지라도 암반 내에 존재하는 불연속 면들의 발달 상태 등 지질공학적 요인에 의하여 암반이 취약해지는 경우, 지반 내에 발달하는 불연속면의 사전 인지와 이에 대한 대책 공법 수립의 필요성, 충분하지 못한 사전 지반 조사에 의해 터널 상부에 존재하는 충적층을 사전에 예측하지 못하여 발생된 사고 사례들과 시공 중 지반 조사(막장 관찰, 갱내 선진시추 조사 등) 결과가 터널의 시공에 적용된 예와 특수한 지반조건에서의 터널 변형 사례등을 검토하였다. 결론적으로 터널 시공에 있어서 대상 지반의 지질공학적 특성을 충분히 파악할 수 있는 적절한 지반 조사를 충실히 이행하면 지반 관련 사고를 미연에 방지할 수 있고 경제적인 시공이 될 수 있을 것으로 판단하였다.

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Enhancement of Dissolution Properties of Ketoprofen from Ground Mixtures with Chitin or Chitosan

  • Koh, Ik-Bae;Shin, Sang-Chul;Lee, Yong-Bok
    • Journal of Pharmaceutical Investigation
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    • v.16 no.1
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    • pp.36-41
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    • 1986
  • The ground mixtures of ketoprofen with chitin or chitosan were prepared by grinding in a ball mill to increase the dissolution rate. The ground mixture showed a faster and more enhanced dissolution rate than the physical mixture or intact ketoprofen. The X-ray diffraction peaks indicated the production of the amorphous form of ketoprofen in the ground mixture. An interaction, in the ground mixture, such as association between the functional groups of ketoprofen and chitin or chitosan might occur in the molecular level. The endothermic peak due to the fusion of ketoprofen disappeared in the ground mixture indicating the different thermal property. The co-grinding technique with chitin or chitosan provided a promising way enhancing the dissolution rate of practically insoluble drug.

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