http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
점토지반에 이중벽체가 적용된 해상폐기물매립장의 적정 차수 기준
황웅기,김향은,최호성,김태형 한국지반공학회 2019 한국지반공학회논문집 Vol.35 No.8
This study was conducted to propose a reasonable requirement regulation of cutoff barriers composed of bottom layer and vertical barrier of offshore landfill for the prevention of contaminant leakage. The bottom layer was composed of impermeable clay layer; vertical walls were composed of double walls; outer wall was composed of steel sheet pile which registed against outer force; cutoff vertical barrier took the role of inner wall. Seepage-advection-dispersion numerical analysis was conducted using SEEP/W and CTRAN/W programs under steady and unsteady flows. The results showed that the values calculated under steady flow showed higher migration of pollutant than those of unsteady flow. The values calculated under steady flow are more valid from a design point of view. Under steady flow and the bottom clay layer and when the vertical barrier are homogeneous and completely well installed, respectively, the minimum required cutoff regulations for hydraulic conductivity, thickness, and embedded depth of the bottom clay layer and vertical barrier were suggested.
ACOUSTIC EMISSION CHARACTERISTICS OF STRESS CORROSION CRACKS IN A TYPE 304 STAINLESS STEEL TUBE
황웅기,배승기,김재성,강성식,곽노권,이보영 한국원자력학회 2015 Nuclear Engineering and Technology Vol.47 No.4
Acoustic emission (AE) is one of the promising methods for detecting the formation ofstress corrosion cracks (SCCs) in laboratory tests. This method has the advantage of onlineinspection. Some studies have been conducted to investigate the characteristics of AEparameters during SCC propagation. However, it is difficult to classify the distinct featuresof SCC behavior. Because the previous studies were performed on slow strain rate test orcompact tension specimens, it is difficult to make certain correlations between AE signalsand actual SCC behavior in real tube-type specimens. In this study, the specimen was aAISI 304 stainless steel tube widely applied in the nuclear industry, and an accelerated testwas conducted at high temperature and pressure with a corrosive environmental condition. The study result indicated that intense AE signals were mainly detected in the elasticdeformation region, and a good correlation was observed between AE activity and crackgrowth. By contrast, the behavior of accumulated counts was divided into four regions. According to the waveform analysis, a specific waveform pattern was observed during SCCdevelopment. It is suggested that AE can be used to detect and monitor SCC initiation andpropagation in actual tubes.
정상류 조건에서 경사식호안 해상폐기물매립장의 차수에 대한 침투이류 분산해석
황웅기,김향은,김태형 한국지반신소재학회 2019 한국지반신소재학회 논문집 Vol.18 No.4
This study was conducted to propose a reasonable requirement regulation of barrier system of rubble mound revetment offshore landfill for preventing contaminant leakage. The barrier is composed with bottom layer and side barrier. The bottom layer was assumed as impermeable clay layer and side barrier was composed with HDPE sheet (primary element) and mid-protection layer (supplementary element). Seepage-advection-dispersion numerical analysis has been conducted using SEEP/W and CTRAN/W programs under steady flow. As the results, the minimum required barrier regulations for hydraulic conductivity and thickness of the bottom layer were suggested. For side barrier, the extended length of HDPE sheet and the hydraulic conductivity of mid-protection layer were also suggested. 본 연구는 오염원 유출을 방지하기 위한 경사식호안 해상폐기물매립장 차수시스템에 요구되는 적절한 기준을 제안하기 위하여 해석을 수행하였다. 차수시스템은 바닥과 측면으로 구성하였다. 바닥차수시스템은 불투수 점토층이 측면차수시스템은HDPE 차수시트가 주 역할을 하고 부수적으로 중간보호층이 차수를 담당한다. SEEP/W와 CTRAN/W 프로그램을 이용하여침투・이류 분산 해석을 실시하였다. 해석결과, 바닥차수시스템인 점토층에 대하여 요구되는 투수계수와 두께가 제안되었다. 측면차수시스템인 HDPE 차수시트에 대해서는 설치길이와 중간보호층에 대해서는 요구되는 투수계수가 제안되었다.
동적 파랑에 의한 침투류가 사석경사식 방파구조물의 안정성에 미치는 영향
황웅기,김태형,김도삼,오명학,박준영 한국지반공학회 2018 한국지반공학회논문집 Vol.34 No.3
To study how stable the rubble mound breakwaters are, one can look to the research of wave induced seepage flow through the pores of the rubble mound. Seepage flow is generally generated by the difference between the water level around the breakwater during a typhoon. The existing stability analysis method of the rubble mound is the static analysis which simply considers the force equilibrium taking into account the horizontal force acting on the concrete block induced by a wave (calculated by Goda equation) and the vertical force induced by the weight inclusive of the concrete block, quarry run, filter, and armor layer above the slipping plane. However, this static method does not consider the wave-induced seepage flow in the rubble mound. Such seepage may decrease the stability of the rubble mound. The stability of a rubble mound breakwater under the action of seepage was studied based on the results of CFD software (OpenFOAM) and Limit Equilibrium Method (GeoStudio). The numerical analysis result showed that the seepage flow decreased the stability of the rubble mound breakwaters. The results of the numerical analyses also revealed the stability of the rubble mound was varied with time. Especially, the most critical state happened at the condition of overtopping the concrete block, acting strong uplift pressure raising along side and underneath the concrete block, and generating high pore pressure inside rubble mound due to seepage flow. Therefore, it may be necessary to conduct a dynamic analysis considering the effect of wave-induce seepage flow together with the static analysis.
황웅기,강기민,김태형,송영석 한국지반공학회 2012 한국지반공학회논문집 Vol.28 No.2
The purpose of this study is to determine the effect of soil grain size and its distribution on soil-water characteristic. To do this, soil-water characteristic tests were conducted on Saemangeum silt using the axis translation technique. For comparison, the test was also conducted on Jumunjin sand. Using the test results, the soil-water characteristic curves (SWCCs) of Saemangeum silt and Jumunjin sand were predicted by Van Genuchten model. By comparison and analysis between two SWCCs, the silt shows higher values of matric suction, water content, and air entry value than the sand. On the other hand, the sand has higher values of Van Genuchten model parameters of , , than the silt. It indicates that the SWCC is significantly dependent on the structure of soils. In other words, if a soil has relatively high grain size and poor grain size distribution curve, the values of saturated volumetric water content, residual volumetric water content, and air entry value are small, and the variation of volumetric water content is high in accordance with the matric suction variation, and consequently it shows a narrow range of funicular region.
정상류하 침투·이류 분산 해석을 이용한 폐기물 해상최종처리장 차수시스템의 최적 성능 평가
황웅기(Woong-Ki Hwang),오명학(Myoung-Hak Oh),김태형(Tae-Hyung Kim),김향은(Hyang Eun Kim) 한국해안해양공학회 2018 한국해안해양공학회 논문집 Vol.30 No.2
본 연구는 정상류 조건에서 폐기물 해상최종처리장에서의 오염원의 누출 방지에 필요한 최적의 최소기준을 제안하기 위하여 각각 바닥 및 연직 차수시스템의 기본적인 차수공에 대하여 침투·이류 분산해석을 수행하였다. 연구 결과 바닥 차수시스템의 최소기준으로 투수계수 1 × 10<SUP>−6</SUP> cm/s 이하인 불투수성 지층이 두께 500 cm 이상이거나 이와 동등한 차수효과를 가진 차수시스템이어야 한다. 연직 차수시스템의 최소기준으로 투수계수 1 × 10<SUP>−6</SUP> cm/s 이하인 두께 50 cm 이상이거나 이와 동등한 차수효과를 가진 차수시스템을 설치하여야 한다. 또한, 연직 차수시스템은 바닥 차수시스템과 일체가 되어 차수기능을 발휘하도록 충분한 근입깊이가 필요하다. This study was conducted to propose the optimum minimum requirement of cutoff system composed of the impermeable soil layer and vertical barrier in offshore landfill for prevention pollution leakage by seepage, advection, and dispersion numerical analyses under steady state. According to the study results, the minimum requirement of impermeable soil layer is below 1 × 10<SUP>−6</SUP> cm/s of hydraulic conductivity with more than 500 cm thickness or a system with equivalent cutoff effect. The minimum requirement of vertical barrier is below 1 × 10<SUP>−6</SUP> cm/s of hydraulic conductivity with more than 50 cm thickness or a system with equivalent cutoff effect. In addition, the vertical barrier should be embedded enough to seal securely with the impermeable soil layer for working cutoff effect.