• Structural Engineering and Mechanics
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• 제21권1호
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• pp.101-119
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• 2005

An efficient methodology is presented to evaluate the seismic behavior of a Fluid-Elevated Tank-Foundation/Soil system taking the embedment effects into accounts. The frequency-dependent cone model is used for considering the elevated tank-foundation/soil interaction and the equivalent spring-mass model given in the Eurocode-8 is used for fluid-elevated tank interaction. Both models are combined to obtain the seismic response of the systems considering the sloshing effects of the fluid and frequency-dependent properties of soil. The analysis is carried out in the frequency domain with a modal analysis procedure. The presented methodology with less computational efforts takes account of; the soil and fluid interactions, the material and radiation damping effects of the elastic half-space, and the embedment effects. Some conclusions may be summarized as follows; the sloshing response is not practically affected by the change of properties in stiff soil such as S1 and S2 and embedment but affected in soft soil. On the other hand, these responses are not affected by embedment in stiff soils but affected in soft soils.

• Structural Engineering and Mechanics
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• 제89권4호
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• pp.421-436
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• 2024

This research addresses experimentally the relationship between the excitation frequency and both hoop and axial wall stresses in a water storage tank. A low-density polyethylene tank with six different aspect ratios (water level to tank radius) was tested using a shake table. A laminar box with sand represents a soil site to simulate Soil-Structure Interaction (SSI). Sine excitations with eight frequencies that cover the first free vibration frequency of the tank-water system were applied. Additionally, Ricker wavelet excitations of two different dominant frequencies were considered. The maximum stresses are compared with those using a nonlinear elastic spring-mass model. The results reveal that the coincidence between the excitation frequency and the free-vibration frequency of the soil-tank-water system increases the sloshing intensity and the rigid-like body motion of the system, amplifying the stress development considerably. The relationship between the excitation frequency and wall stresses is nonlinear and depends simultaneously on both sloshing and uplift. In most cases, the maximum stresses using the nonlinear elastic spring-mass model agree with those from the experiments.

• 한국환경보건학회지
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• 제11권2호
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• pp.29-39
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• 1985

This experimental study was carried out to evaluate the improvement of rural privys and to develop the system of the three septic tank privy. For this study, 42 samples of excreta, 42 samples of soil and 26 samples of vegetables were drawn out of the conventional privys while 26samples of excreta, 26samples of soil and 26samples of vegetables out of the three septic tank privys from five villages in Chun Song County. Kang Won Province for the period from 22th August to 13th October, 1984. The major findings are as follows : 1. Positive cases of helminthes are found 41 out of 42(97.6%) excreta of the conventional privys whereas those from the three septic tank privys are found 2 out of 26 (7.7%). Average numbers of helminthes from the excreta of the conventional privys are 4.4 whereas those from the three septic tank privys are 1.1. 2. Positive cases of helminthes are found 33 out of 42 (78.6%) soil of the conventional privys whereas those from the three septic tank privys are found 20 out of 26(76.9%). However, this difference does not reveal statistical significance (P>0.01). Average numbers of helminthes from the soil of the conventional privys are 2.3 whereas those from the three septic tank privys are 1.7 and the difference in total number of helminthes reveals statistical significance (P<0.05). 3. Positive cases of helminthes from vegetable samples drawn out of the conventional privys are found 13 out of 26(50.0%) whereas those froin the three septic tank ptivys are found 10 out of 26(38.5%). Average numbers of helminthes from vegetable samples drawn out of the conventional privys are 1.1 whereas those from the three septic tank privys are 0.7. However, these differences in both positive rates and total numbers of helminthes do not reveal statistical significance (P>0.05).

• 유기물자원화
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• 제17권3호
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• pp.40-47
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• 2009

토양으로 유출된 비수용상액체(nonaqueous phase liquid; NAPL)의 제거를 위한 알코올 희석 세정공정의 기술개발을 위하여 3-D 토양탱크에서 NAPL 흡수 및 비흡수 알코올 단독 또는 공기 동시 주입공정에 의한 벤젠 NAPL 제거 효과를 평가하였다. 37L 규모의 토양탱크에 729mL의 벤젠을 주입하고 70%에탄올 (NAPL 비흡수 알콜)과 40%이소 프로판올(NAPL 흡수 알콜)을 탱크 하부에 설치된 주입정에 주입하고 상부의 추출정으로부터 자유상 NAPL 및 수용액을 추출하였다. 그리고 알코올 주입과 공기를 동시 주입하여 기존 토양칼럼실험에서 확인된 공기 동시주입시 화학세정 증대 효과를 아울러 평가하였다. 70% 에탄올 및 40% 이소-프로판올에 의한 토양탱크 세정공정 결과 전체 벤젠 제거율의 과반수는 자유상 NAPL 형태로 제거되었다. 알코올의 NAPL 흡수 특성에 따라 벤젠 제거 특성이 현저히 다르게 나타난 토양칼럼결과와 달리 3-D공정에서는 알코올 NAPL 흡수특성의 영향이 매우 적게 나타났다. 70%에탄올과 공기 동시 주입에 의한 벤젠 제거 증대 효과는 3-D 토양탱크 실험결과에서도 여전히 확인되었다. 그러나 NAPL 흡수 알코올인 40% 이소-프로판올은 공기 동시 주입에 의한 벤젠 제거 증대효과가 여전히 미미하게 나타났다. 3-D 토양탱크 실험결과 화학세정공정에 의한 NAPL제거에 있어 가장 중요한 인자는 추출정의 NAPL 및 유출수 추출능력이었다. 즉 토양내 효과적인 NAPL 정화를 위해서는 화학적인 작용에 의하여 이동된 자유상 NAPL 및 수용액을 밖으로 효율적으로 추출할 수 있는 공정이 필요하다.

• 대한토목학회논문집
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• 제33권4호
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• pp.1337-1347
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• 2013

원통형 GFRP 개인하수 처리시설의 극한거동에 대한 매개변수해석을 수행하였다. 지반을 비선형 스프링으로 대체한 해석모델과 3차원 고체요소를 적용한 두 가지 해석모델이 작성되었다. 보강링의 형태와 지반조건의 변화에 따른 개인하수처리시설의 극한거동이 분석되었다. Ramberg-Osgood 모델과 Druker-Prager 모델이 각각 GFRP 및 지반의 비선형성을 나타내기 위하여 적용되었다. 원통형 개인하수처리시설 내부에 설치된 강관 보강링의 직경과 두께 및 지반 탄성계수 및 내부마찰각 등을 매개변수로 하여 하중-변위 관계, 축방향 변형률 및 후프방향 변형률 등이 유한요소해석을 통하여 도출되었고 여러 매개변수들이 강관으로 보강된 개인하수처리시설의 극한강도에 미치는 영향들이 분석되었다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1998년도 공동 심포지엄 및 추계학술발표회
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• pp.169-173
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• 1998

The practice of the construction and management of the underground petroleum storage facilities in Korea was investigated extensively, and the problems were identified. The advanced technologies in the U.S.A was comparatively studied. Considering the effectiveness of leak prevention and technology applicability, the following measures were suggested. To prevent corrosion of the tank, a clad tank, an interior-lining tank, or a double-wall tank was appropriate and appeared to be most cost effective. For piping, non-metalic material was suggested. To prevent spill, a catchment basin can be effective. For monitoring of leak, construction of more than one of one or combination of an automatic leak-detection device, a vapor-detection system, a ground water-monitoring system, and a double-wall detection system was recommended.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1218-1231
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• 2008

Recently the energy dependence of LNG resource is being increased. So the enlargement of LNG storage is constructed in the coastal area. Most of LNG tanks are constructed below the ground level, and thus the hydraulic uplift pressure could be a problem against the weight of tank structure. Specifically, the settlement of foundation soil in the LNG tank is also important in the aspect of safety. The low temperature around LNG tank is induced the ground freezing and hence increasing the soil volume and earth pressure. The additional lateral earth pressure due to ground freezing could be applied to the LNG tank. In this study, the stability of LNG storage tank was evaluated with consideration of freezing earth pressure by using computer program TEMP-W.

• 한국전산구조공학회논문집
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• 제32권3호
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• pp.155-164
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• 2019

이 연구에서는 기초의 종류에 따라 지반-구조물 상호작용(SSI) 효과가 LNG 저장탱크의 지진응답해석에 미치는 효과를 분석하였다. 이를 위하여 직경 71m인 LNG 탱크와 기반암 위 점토지반의 깊이가 30m인 지반조건을 고려하였다. 그리고 기초형식으로 네 가지(얕은 기초, 말뚝지지 전면기초, 말뚝기초(지표면 접촉식, 부유식)를 고려하였다. 지반의 비선형성은 자유장 지반에 대하여 등가선형화기법으로 고려되었다. 또한, 말뚝기초의 시공과정에서 발생하는 동다짐 효과에 대해서도 분석하였다. SSI 해석을 위하여 진동수영역 해석프로그램인 KIESSI-3D를 이용하였다. 지반-구조물 상호작용 해석을 통해 LNG 저장탱크의 외조 벽체 쉘의 응력과 내조탱크의 밑면전단력 및 전도모멘트를 구하였다. 해석결과로부터 다음과 같은 결론을 얻을 수 있었다: (1) 고정 기초해석에 의한 외조와 내조탱크의 지진응답이 SSI 효과로 인한 지진응답보다 매우 컸다. (2) SSI의 효과가 내조탱크와 외조탱크의 동적응답에 미치는 영향은 기초의 형식에 따라 다르게 나타난다. (3) 말뚝지지 전면기초에서 동다짐 효과에 의한 구조물 응답의 변화는 약 10%로서 무시할 수 없을 정도로 큰 것으로 나타났다.

• Coupled systems mechanics
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• 제5권3호
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• pp.223-234
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• 2016

The main purpose of current study is to find the soil effects on natural period of elevated tank. The coupled analytical method is used to assess in this study. The current study presented models which are capable to consider the soil dynamic stiffness changes and fluid- structure interaction effects on natural period of elevated tanks. The basic of mentioned models is extracted from elastic beam and lumped mass theory. The finite element is used to verify the results. It is observed that, external excitation can change the natural period of elevated tanks. Considering the increase of excitation frequency, the natural period will be decreased. The concluded values of natural period in case of soft and very soft soil are more affected from excitation frequency values. The high range of excitation frequency may reduce the natural period values. In addition it is observed that the excitation frequency has no significant effect on convective period compare with impulsive period.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2002년도 추계 학술발표회 논문집
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• pp.98-105
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• 2002

The effects of the base-isolation system and elastic soil foundation on the behavior of a liquid storage tank are studied. To evaluate the seismic response of liquid storage tank accurately, the coupled dynamic system considering base isolation and soil interaction problem is formulated in time domain. Results show that the base isolation system reduces effectively the radial displacements, base shears, overturning moments, axial resultant stresses and the hydrodynamic pressure by providing flexibility and energy dissipation capability. Base Isolation may, however, increase the relative liquid sloshing amplitude due to the effect of liquid-structure interaction and cause excessive large relative displacements between structure and foundation. In addition to base-isolator, the dynamic behavior of liquid storage tank is related to the flexibility of base foundation, so the analysis of soil-structure interaction s achieved.