• Title, Summary, Keyword: Ground investigation

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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.

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

  • 배미혜;권오성;한상환
    • Proceedings of the Computational Structural Engineering Institute Conference
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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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A Study on Geotechnical Lineament Analysis by Image Processing Method (영상사진을 이용한 지반공학적인 선구조분석 연구)

  • 이수곤;금동헌
    • Proceedings of the Korean Geotechical Society Conference
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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.

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

  • Jeon, Je-Sung;Kim, Ki-Young;Lee, Sang-Duk;Kim, Doo-Jun
    • Proceedings of the Korean Geotechical Society Conference
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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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Investigation into the Input Earthquake Motions and Properties for Round Robin Test on Ground Response Analysis (지반 응답 해석 Round Robin Test의 입력 지진파 및 물성에 관한 고찰)

  • Sun, Chang-Guk;Han, Jin-Tae;Choi, Jung-In;Kim, Ki-Seog;Kim, Myoung-Mo
    • Proceedings of the Korean Geotechical Society Conference
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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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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- (중부지방 상록지피식물의 조경적 이용 -광이 월동중의 엽색에 미치는 영향을 중심으로-)

  • Nam, Yu-Kyeong;Kim, Myung-Hyoe
    • Journal of agriculture & life science
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    • v.45 no.2
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    • pp.1-7
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    • 2011
  • Three evergreen ground-cover species were tested and evaluated for cold acclimation with different lights in central Korea to enrich the varieties of ground cover plants for over-wintering. Nandina domestica which recently started to be planted in central Korea had high chlorophyll unit with shade condition in both locations, Banpo and Gwacheon during winter. Light condition had no influence on chlorophyll unit in Banpo after April, meanwhile full sun condition decreased chlorophyll unit significantly in Gwacheon, which is exposed to cold wind from north. Ophiopogon japonicas had more than double chlorophyll unit in shade condition compared to that in full light condition in both investigation areas in February. In addition, higher value of L and b in shade condition had been maintained than in full sun condition throughout investigation period. However, leaves in Gwacheon were de-colorized in full sun condition after over-wintering. Pachysandra terminalis had more higher chlorophyll unit in shade condition compared to in full sun condition in both investigation areas in February. But light conditions had not effect the difference of chlorophyll unit of Gwacheon in April. Therefore, The present results suggest that evergreen ground covers with shade condition would be used as landscape materials in the capital area.

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

  • Park, Nam-Seo;Lee, Chi-Mun;Gang, Sang-Ho
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.47-60
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    • 1998
  • It is considered in this paper that the main causes of tunnel collapse during the construction were the insufficiency of data of geotechnical investigations, or their limits due to special ground condition such as its heterogeneity and anisotropy It is thought that safety of ground can be affected by the geological conditions such as presences of discontinuities in good intact rocks, and considered to be necessary that awareness of the conditions of discontinuities in advance is important to apply adequate reinforcement measures. It is also shown that a serious accident had occurred because of the unawareness of the permeable alluvial deposits at the top of the tunnel. And it is shown that the example of application of the results of geotechnical investigation such as face-mapping, pilot boring etc. during tunnel construction, and a serious deformation of tunnel under special geological condition. Therefore, it is strongly recommended to perform an adequate geotechnical investigation to confirm the geotechnical conditons of ground before design, and supplimentary investigation is also needed depending on conditions for safe and econonic construction.

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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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