• Magazine of korean Tunnelling and Underground Space Association
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• v.25 no.1
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• pp.5-15
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• 2023

• Journal of the Korean Geotechnical Society
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• v.37 no.12
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• pp.73-87
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• 2021

Pile-supported wharf is a structure that can transmit and receive cargo, and it is mainly installed on saturated inclined ground. In the seismic design of these structures, the codes suggest using the response spectrum analysis method as a preliminary design method. However, guideline on modeling method for pile-supported wharf installed in saturated soil is lacking. Therefore, in this study, the dynamic centrifuge model test and response spectrum analysis were performed to evaluate the seismic performance of pile-supported wharf installed into the saturated soil. For the test, some sections (3×3 pile group) among the pile-supported wharf were selected, and they were classified into two model (dry and saturated sand model). Then the response spectrum analysis was performed by using the soil spring method to the test model. As a result of test and analysis, the m om ent difference occurred within a m axim um of 51% in the dry sand m odel and the saturated sand model where liquefaction does not occur, and it was found that the pile moment by depth was properly simulated. Therefore, in the case of these models, it is appropriate to perform the modeling using the Terzaghi (1955) constant of horizontal subgrade reaction (n_h)

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.108-111
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• 2012

최근에 태풍 매미 등 이상 기후로 인한 기상이변이 빈번히 발생함에 따라 그에 대한 대처방안을 모색하기 위해 2005년 해양수산부에서는 지역 및 해역별 특성을 분석하여 종전 설계기준을 강화하였다. 하지만, 기존에 설계된 항만 구조물의 마루높이 및 피복재 중량 등이 새로 개정된 설계기준에 미치지 못하는 등 안전성에 대한 문제가 발생하고 있으며, 이러한 문제점을 개선하기 위해 기존 방파제를 보강하는 여러 방식이 제안되고 있다. 그 중 부유식방파제는 해수의 소통을 방해하지 않는 친환경적인 구조물로써, 연약지반에 시공이 가능하고 시공 시 오탁이 적게 발생하여 시공이 편하다는 장점을 가지고 있다. 또한 구조물의 해체 및 보강시 건설폐기물을 발생시키지 않는 친환경적인 구조물이기 때문에 새로운 방식의 대체 외곽항만구조물로 관심을 받고 있다. 이에, 본 연구에서는 사석경사제 전면에 부유식구조물을 설치하여 방파제 보강하는 방안을 제시하고자, 부유식구조물을 통과한 파랑이 사석경사제와 만나 발생하는 처오름높이를 분석하였다. 본 수치모의에서는 유체의 점성 및 난류특성을 포함하고 있는 Navier-Stokes 방정식을 그대로 해석하는 2차원 수치파동수조(CADMAS-SURF)를 이용하여 수치 모의을 수행하였다. 부유식구조물은 불투수성구조물로 수면에 고정시키는 방식을 적용하여 사석경사제의 전면에 설치하였으며, 고정된 부유식구조물의 흘수심을 변화시켜 사석경사제에서의 처오름높이를 산정하였다.

• Journal of the Korean Geotechnical Society
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• v.17 no.4
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• pp.221-229
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• 2001

연약지반의 측방유동으로 인한 피해가 예상되는 국내 현장에 성토지지말뚝공법을 적용하기 위한 연구의 일환으로 실제 현장에서 성토지지말뚝이 발휘하는 효과를 규명하기 위한 현장시험이 계획되었다. 본 현장시험은 직경 40.64cm의 강관말뚝을 3본씩 총 4여로 시공하고, 각 열의 줄말뚝은 콘크리트캡보로 연결한 다음 총 8m까지 성토하였다. 현장시험은 총 2회에 걸쳐 수행하였으며, 성토지지말뚝의 하중분담효과를 확인하기 위해 하중계, 토압계, 지중경사계, 그리고 침하판을 이용한 계측을 실시하였다. 또한 계측결과를 제안이론식과 비교분석하였다. 이러한 연구 결과 성토지지말뚝을 시공할 경우 성토지지말뚝 위 성토지반속에 발달하는 지반아치에 의해 대부분의 성토하중이 말뚝으로 전이됨을 확인하였고, 말뚝캡보의 설치 간격이 좁을수록, 그리고 성토고가 높을수록 성토지지말뚝의 하중분담효과가 더 커지게 됨을 확인할 수 있었다. 또한 설계시 성토지지말뚝의 설치범위를 합리적으로 결정하기 위해서는 성토지지말뚝이 성토사면의 사면안정효과에 미치는 영향을 고려해야 함을 알 수 있었으며, 제안이론식이 현장상태의 성토지지말뚝에 합리적으로 적용될 수 있음을 입증하였다.

• Journal of the Korean Geosynthetics Society
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• v.18 no.4
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• pp.205-214
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• 2019

Load and resistance factor design of mound breakwater against circular failure was developed in this study. To achieve the goal, uncertainties of parameters of soils, mound, and concrete cap were determined. Eight design cases of domestic mound breakwaters were collected and analyzed. Monte Carlo Simulation was implemented to determine the most critical slip surfaces of the design cases. Using the results of Monte Carlo Simulation, First-Order Reliability Method (FORM) was used to perform reliability analyses. Optimal load and resistance factors were calculated using the reliability analysis results and final load and resistance factors were proposed based on the calculated optimal factors.

• Journal of the Korean GEO-environmental Society
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• v.23 no.5
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• pp.25-32
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• 2022

As recently, there have been two earthquakes with a magnitude of 5.0 or greater in Korea and the number of smaller earthquakes has increased, a lot of research and interest in earthquake-resistant design are increasing. Especially, the Pohang earthquake has also raised interest in earthquake-resistant design of port facilities. In this study, experiments and analysis were conducted on the dynamic behavior of upright and inclined breakwaters during earthquakes among port structures through the 1g shaking table test. To this end, three seismic waves were applied to the model to which the similarity law (scale effect) was applied: long period (Hachinohe), short period (Ofunato) and artificial seismic waves. The acceleration and displacement of the upright and inclined breakwaters were analyzed according to whether the DCM method was reinforced during earthquakes based on the results of shaking table test. As the result, the dynamic behavior of the upright and inclined breakwater shows a tendency to suppress the amplification of acceleration as bearing capacity and rigidity increase when DCM method is reinforced.

• Geotechnical Engineering
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• v.13 no.4
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• pp.37-54
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• 1997

This paper is to investigate the bearing capacity and the failure mechanism of slope subjected to strip surcharges adjassent to embankment slope of sandy soil. Parametric model tests under plain strain condition were performed by changing width of footing, relative density of slope materials, and position of footing from the crest of slopes. For model tests, Jumunjin standard sand was used as the slope material and its relative density was 45% and 70%, respectively. The angle of slope was formed with 1 : 1.5 and 1 2. Rigid model footings, made of aluminuu were used with their widths of 4, 7, 10 and 12cm. For the position of model footing, position ratios, distance of model footing from the crest of slope divided by footing width, were 0, 0.5, 1, 2, 3, 4, 5. Failure mechanism was observed by using ink colored sands and markers inserted in model slopes. Ultimate bearing capacity obtained from tests was analyzed and compared with limit equilibrium method, limit analysis method and empirical equation. Characteristics of load-settlement curves and failure mechanism were also analyzed and compared with the existing theories. Thus, their effects on ultimate bearing capacity of model footing adjacent to slope were assessed.

• Journal of the Korean Geosynthetics Society
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• v.15 no.3
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• pp.39-47
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• 2016

In order to prevent leakage of leachate in offshore landfill, hydraulic barrier is indispensable. In the case of rubble mound revetment at offshore landfill, HDPE sheet in slope should be installed. In this study, seepage analysis were performed to evaluate seepage and flow in the seabed and revetment according to extended length of HDPE sheet by using SEEP/W. Results show that, in the case of low permeability layer is distributed where extended length of HDPE sheet was more than 1m, seepage flux in seabed and revetment was greatly reduced. In order to prevent seepage in seabed and revetment in the case of sand layer of high permeability is existed above low permeable layer, extended length of HDPE sheet and impermeable improvement width of permeable layer should be more than 1m at seabed.

• Proceeding of KASS Symposium
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• 2008.05a
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• pp.70-73
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• 2008

Because the inclination and crack of stone pagoda structure are caused by the depth difference of soft soil ground and ground subsidence in weak zone, a long-term conservation of stone pagoda structure is difficult. But it is insufficient to analyze the behavior of stone pagoda structure considering soft soil ground in our country. Therefore, we find the structural effect happening in stone pagoda structure by analyzing mechanically a specific of soft soil ground and carry out structural analysis and structural modelling of stone pagoda structure that considers soft soil ground by discrete element method.

• Journal of the Korean GEO-environmental Society
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• v.20 no.5
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• pp.13-21
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• 2019

There are many cuts or natural rock slopes that remain stable for a long time in the natural environment with steep slopes ($65^{\circ}$ to $85^{\circ}$). In terms of design practice, the rock mass consisting of similar rock condition and geological structures is defined as a good continuum rock slope, and during the process of decision making angle of this rock slope, it will be important to establish the geotechnical properties estimating method of the continuum rock on the process of stability analysis in the early stages of design and construction. In this study, the stability analysis of a good continuum rock slope that can be designed as a steep slope proposed a practical method of estimating the shear strength by induced from the Hoek-Brown failure criterion, and in addition, the design applicability was evaluated through the stability analysis of steep rock slope. The existing method of estimating the shear strength was inadequate for practical use in the design, as the equivalent M-C shear strength corresponding to the H-B envelope changes sensitively, even with small variations in confining stress. To compensate for this problem, it was proposed to estimate equivalent M-C shear strength by iso-angle division method. To verify the design applicability of the iso-angle division method, the results of the safety factor and the displacement according to the change in angle of the cut slope constructed at the existing working design site were reviewed. The safety factor is FS=16~59 on the 1:0.5 slope, FS=12~52 on the 1:0.3 slope, most of which show a 10~12 percent reduction. Displacement is 0.126 to 0.975 mm on the 1:0.5 slope, 0.152 to 1.158 mm on the 1:0.3 slope, and represents an increase of 10 to 15%. This is a slightly change in normal proportion and is in good condition in terms of stability. In terms practical the working design, it was confirmed that applying the shear strength estimated by Iso-angle division method derived from the H-B failure criterion as a universal shear strength for a good continuum rock mass slope was also able to produce stable and economic results. The procedure for stability analysis using LEM (Limit Equilibrium Analysis Method) and FEM (Finite Element Analysis Method) will also be practical in the rock slope where is not distributed fault. The study was conducted by selecting the slope of study area as a good rock condition, establishing a verification for which it can be applied universal to a various rock conditions will be a research subject later on.