• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.49-59
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• 2010

Earthquake-induced liquefaction on saturated loose sand is well known in the world. Since Saemangeum Dike Project has a plan to be reclaimed with dredged sand on wide river, possibility of liquefaction should be checked. Section Dongjin5 was selected to evaluate possibility of liquefaction. Estimating method follows as 1) determination of PL value with SPT results, passing curve, and soil properties, 2) prediction for maximum earthquake acceleration, 3) calculation for FL value on depth with Korean specification for highway bridges, 4) visualization for possibility of liquefaction on all of project area with GIS 5) comparison with Japanese specification for highway bridges, Youd and Idriss method, and Andrus and Stokoe II method for verification, 6) ascertainment for the potential liquefaction with cyclic triaxial test. 7) establishing for countermeasure if needed. From the results, even though most of area covered with sand, no potential liquefaction exists except some areas. Those need to soil improvement with grout or attaching measurement on substructure.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 가을 학술발표회 논문집
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• pp.427-434
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• 2002

In Korea, there are recently many attempts to expand a temporary soil nailing system into a permanent soil nailing system since the first construction in 1993. In the downtown area, it is important that the relaxation of the ground is minimized in the ground excavation works. Due to these problems, soil nailing systems are often used the flexible facing such as shotcrete rather than the rigid facing such as SCW, CIP, and jet grout types in Korea. The soil nailing systems with rigid facings are used greatly however it is insufficient researches for design and analysis of soil nailing systems with rigid facings. In this study, various laboratory model tests are carried out to examining the influence the rigidity of facings on the global safety of soil nailing system, failure loads, displacement behaviour, axial force acting on the nails, and distribution of earth pressure. Also, the parametric studies are carried out for the typical section of soil nailed walls according to thickness of concrete facings and internal friction angle of soil using the numerical technique as shear strength reduction technique.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1997년도 가을 학술발표회 논문집
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• pp.211-220
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• 1997

• 지질공학
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• 제26권1호
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• pp.15-22
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• 2016

충적 대수층의 수리지질특성 시험을 위한 충적층 공벽 유지장치를 개발하여 변수위법 투수시험(Falling Head Test) 및 순간 충격시험(Slug Test)을 수행하였다. 모래, 자갈을 비롯한 실트층이 주를 이루는 국내 충적층 수리시험은 시험구간의 공벽유지와 시험 중 토사층의 공벽붕괴가 지속적으로 발생하여 투수시험과 순간충격시험 등의 수리시험 수행에 많은 어려움을 겪고 있다. 이에 본 연구는 개공율이 안정적인 필터가 장착된 공벽 유지장치를 시험공에 삽입하여 시험구간 공벽붕괴를 최소화하고 시험시 정확한 단위면적의 산출로 토사층에서의 수리시험 신뢰성을 증대하고자 하였다. 연구결과 기존의 변수위법 투수시험에 의한 투수계수는 8.82 × 10⁻⁵m/sec로 산출되었으며, 동일한 지층, 심도, 시간적인 조건에서 상기 공벽 유지장치 설치 후 투수시험 결과는 4.00 × 10⁻⁴m/sec로 나타나 최대 4.5배 가량의 투수계수 증가현상을 보인다. 이는 시추굴진 중 발생된 세립질의 슬라임이 투수시험 시 시험구간에 피복 또는 충전되어 토사층의 투수성을 저하시키고 시험구간 형성과정에서 최초 원기둥 형태의 시험공벽이 점진적인 붕괴로 인해 토사로 충전되고 시험구간 면적감소에 기인한 현상으로 판단된다. 본 연구는 미고결 충적층의 공벽 유지장치를 현장에 적용하여 시험구간 굴진 시 발생되는 점착력이 낮은 모래, 자갈층의 공벽붕괴에 따른 시험면적 변화가 투수성에 미치는 영향을 평가한 연구로써, 충적 대수층 수리특성 평가의 신뢰성 및 적용성 개선을 위한 기초자료로 활용될 수 있을 것으로 예상된다.

• 지질공학
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• 제30권4호
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• pp.603-615
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• 2020

인공함양의 설계요소 결정은 대수층의 수리지질학적 특성을 고려하여 산정하게 된다. 연구지역의 시험 부지 내 구축된 주입유형별(수직정, Ditch 및 혼합형)로 주입시험을 단계별로 수행한 후 인공함양의 최적 설계요소 인자를 도출 하였다. 주입정의 구경에 따른 주입 효과의 차이가 크지 않은 것으로 분석되었으며 토지 이용의 가용성과 경제성 등을 고려하여 100 mm 규격이 적정한 것으로 평가되었다. 상부 암반까지도 주입 효과가 잘 유지되는 것으로 나타나 주입정 설치심도는 충적층 및 상부 암반층을 대상으로 결정하였다. 한편, Ditch에 의한 주입 방식의 경우에는, 10~30 mm의 여재를 채운 경우에 침투효율과 수리간섭영향이 우수한 주입 성능을 보이는 것으로 분석되었다. 또한, 수직주입정의 간격 차이에 따른 간섭효율 분석 결과, 각 주입공 간격 1 m 당 간섭효율 감쇄계수는 1.75% 산출되었으며, 주입정의 적정 간격은 9~12 m로 분석되었다. 향후 본 연구에서 산정한 인공함양 설계요소를 현장 시공 및 운영에 적용하여 검증한다면 상시 물부족 지역의 용수 확보에 기여할 것으로 본다.

• 한국안전학회지
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• 제27권1호
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• pp.86-95
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• 2012

The BWIM(Bridge Weigh-In-Motion) is a technology to identify vehicle properties, such as weight, speed, axle spacing and running lane, passing over a bridge by using dynamic response of bridge member. Such information will be used for assessing durability and establishing a maintenance strategy of roadway structures. In this paper, as a first step for developing BWIM system, analytical and experimental studies were conducted in order to verify whether the response of vertical stiffener in steel girder bridge can be used to identify vehicle properties running on the bridge. It was known from this study that such vehicle information could be estimated reasonably by using strain time history curve of a vertical stiffener due to running vehicles. It is because the effect of each axle-load of vehicle appears definitely in the curve. However, as the magnitude of strain of vertical stiffener is effected by running pattern of vehicles, further study is necessary to reduce error when estimating vehicle weight.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.113-120
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• 2005

Soil nailing system can be mentioned to a method of supporting as the shear strength of in-situ soils is increased by passive inclusions. In the general soil nailing system, facing walls are used in two kind of a lattice concrete block or a cast in placed concrete wall. A case of lattice concrete blocks is used in slow slopes greater than 1:0.7. Also, a case of a cast in placed concrete wall is used in steep slopes less than 1:0.5. The cast in placed concrete walls are constructed to 30cm thick together with a shotcrete facing. In this study, the assembling soil nailing method as a new soil nailing system is proposed. This method is constructed assembly using precast concrete panels. Therefore ability of the construction and quality of the facings can be modified than a usual soil nailing system. Also, this method can be obtained the effects that a global slope stability increase, as precast concrete panels is put on cutting face after excavating a slope.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.799-806
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• 2004

Recently, as the forerunner in establishing the Northeast Asia's logistics base, a lot of marine engineering works such as new ports and container terminals, extension of old ports, new bridges, land reclamation etc. have been progressed. Parallel to it, there is also an increasing demand for improving the safety of construction. In this situation, high resolution seismic reflection profiling can be well used, attempting to classify rocks and sediments under water, if possible, to delineate the distribution of grain sizes in sediments not only for calculating the cost of removing sediments from harbour's channels, but also for estimating the bearing capacities for bridge or port construction. However, the results from the corresponding reflection survey that has been in operation in our country can not be effectively used for engineering purposes mostly due to the insufficient resolution. Thus. in this paper, two innovative strategies are introduced to enhance resolution. The one deals with a newly designed exploration barge that will help reduce several kinds of noises encountered electrically or operationally. The other is associated with an establishment of optimum measuring system comprising e.g. a specially devised hydrophone with a combination of 7 piezoelectric elements. Field experiments performed at Busan harbour are illustrated. The quality of acquired data was thereby fundamentally improved in comparison with that obtained at the same time in a conventional way.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.807-814
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• 2004

Land seismic reflection survey has been increasingly demanded in various civil engineering works because of its own ability to delineate layers, water table, to detect cavities or fracture zones, to estimate seismic velocities of each layer. However, our shallow subsurface structures are very complex. The relatively thin layer(mostly soil) to the wavelength directly followed by a basic rock with high impedance used to generate complicated surface waves, kind of channel waves with high amplitude that is dominate in entire seismograms and hence the useful reflection events will be almost hopelessly immersed in the undesired surface waves. Thus, it would seem that the use of traditional seismic survey could not be likely to provide in itself a satisfactory information about our exploration targets. This paper hence introduces an efficient measuring strategy illustrating a properly controlled arrangement of the vertical single force sources commonly used, yielding a very sharply elongated form of P-energy with a minimum of S radiation energy, what we call, P-beam source. Abundant experiments of physical modeling showed that in that way the surface waves could be enormously reduced and the reflection events would be additive and thus reinforced. Examples of field data are also illustrated. The contribution of P-beam source will be great in civil engineering area as well as in general geological exploration area.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.643-650
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• 2009

The necessary consequence by the rapid economic growth in large-scale urban excavation is increasing. If the site is the congested in downtown, the scale of excavation will get the large-scale and the extreme depth. We have achieved a high level technology internationally by the design and construction of underground excavation since 1980's. But the accidents during excavation are frequently occurring. So, this demage instigates the human life loss as well as economical loss. The recent accident is come about the damage for public facilities such as the railroad, subway and etc. in addition to the loss of life and property. For these reasons, the recent accident is being caused the damage of copious social overhead capital. The reasons of collapse during excavation can be classified roughly into the administrative part(sanction, permission), the investigation and design, the construction and management and etc. In this study the close check for the cases of the recent collapse is performed and the improvement course for the prevention of collapse is found.