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Investigation of the dynamic behaviour of a storage tank with different foundation types focusing on the soil‐foundation‐structure interactions using centrifuge model tests 
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下载免费PDF全文 Heon‐Joon Park Jeong‐Gon Ha Sun‐Yong Kwon Moon‐Gyo Lee Dong‐Soo Kim 《地震工程与结构动力学》2017,46(14):2301-2316
This paper proposes a dynamic centrifuge model test method for the accurate simulation of the behaviours of a liquid storage tank with different types of foundations during earthquakes. The method can be used to determine the actual stress conditions of a prototype storage‐tank structure. It was used in the present study to investigate the soil‐foundation‐structure interactions of a simplified storage tank under two different earthquake motions, which were simulated using a shaking table installed in a centrifuge basket. Three different types of foundations were considered, namely, a shallow foundation, a slab on the surface of the ground connected to piles and a slab with disconnected piles. The test results were organised to compare the ground surface and foundation motions, the slab of foundation and top of structure motions and the horizontal and vertical motions of the slab, respectively. These were used to establish the complex dynamic behaviours of tank models with different foundations. The effects of soil–foundation–structure interaction with three foundation conditions and two different earthquake motions are focused and some important factors, that should be considered for future designs are also discussed in this research. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
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Degradation of crude oil in a contaminated tidal flat area and the resilience of bacterial community
Jaejin Lee Il Han Bo Ram Kang Seong Heon Kim Woo Jun Sul Tae Kwon Lee 《Marine pollution bulletin》2017,114(1):296-301
Crude oil spills, Hebei Spirit in South Korea, is considered as one of the worst environmental disasters of the region. Our understanding on activation of oil-degrading bacteria and resilience of microbial community in oil contaminated sites are limited due to scarcity of such event. In the present study, tidal flat sediment contaminated by the oil spill were investigated for duration of 13 months to identify temporal change in microbial community and functional genes responsible for PAH-degradation. The results showed predominance of previously known oil-degrading genera, such as Cycloclasticus, Alcanivorax, and Thalassolituus, displaying significant increase within first four months of the accident. The disturbance caused by the oil spill altered the microbial community and its functional structures, but they were almost restored to the original state after 13 months. Present study demonstrated high detoxification capacity of indigenous bacterial populations in the tidal flat sediments and its resilience of microbial community. 相似文献
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The discharge and water level of a gaining stream are known to be maintained during dry spells by baseflow, which is defined as discharge from underground storage. However, the effect of baseflow on a real river is not well known because direct measurements of baseflow in field are difficult to conduct. Therefore, this study attempts to clarify the contribution of baseflow to streamflow and the extent to which the water level is maintained even during dry spells. A digital filter technique is applied to the records of daily mean streamflow in order to estimate the amount of baseflow, and the lateral distribution method is applied to irregular cross sections at observational sites to obtain the stage–discharge rate curve. Through a comparison of the observed data and calculation results, the amount of baseflow is estimated across the channel, in addition to the maximum water level retained during dry spells in relation to the baseflow. Finally, based on the results of an energy conservation model, this study proposes that the source of the amount of baseflow estimated across a channel section may be different from that of the water level maintained during dry spells. 相似文献
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Sang Heon Lee Jongseong Ryu Jung-woo Park Dabin Lee Jae-Il Kwon Jingping Zhao SeungHyun Son 《Ocean Science Journal》2018,53(3):475-485
The Bering and Chukchi seas are an important conduit to the Arctic Ocean and are reported to be one of the most productive regions in the world’s oceans in terms of high primary productivity that sustains large numbers of fishes, marine mammals, and sea birds as well as benthic animals. Climate-induced changes in primary production and production at higher trophic levels also have been observed in the northern Bering and Chukchi seas. Satellite ocean color observations could enable the monitoring of relatively long term patterns in chlorophyll-a (Chl-a) concentrations that would serve as an indicator of phytoplankton biomass. The performance of existing global and regional Chl-a algorithms for satellite ocean color data was investigated in the northeastern Bering Sea and southern Chukchi Sea using in situ optical measurements from the Healy 2007 cruise. The model-derived Chl-a data using the previous Chl-a algorithms present striking uncertainties regarding Chl-a concentrations – for example, overestimation in lower Chl-a concentrations or systematic overestimation in the northeastern Bering Sea and southern Chukchi Sea. Accordingly, a simple two band ratio (Rrs(443)/Rrs(555)) algorithm of Chl-a for the satellite ocean color data was devised for the northeastern Bering Sea and southern Chukchi Sea. The MODIS-derived Chl-a data from July 2002 to December 2014 were produced using the new Chl-a algorithm to investigate the seasonal and interannual variations of Chl-a in the northern Bering Sea and the southern Chukchi Sea. The seasonal distribution of Chl-a shows that the highest (spring bloom) Chl-a concentrations are in May and the lowest are in July in the overall area. Chl-a concentrations relatively decreased in June, particularly in the open ocean waters of the Bering Sea. The Chl-a concentrations start to increase again in August and become quite high in September. In October, Chl-a concentrations decreased in the western area of the Study area and the Alaskan coastal waters. Strong interannual variations are shown in Chl-a concentrations in all areas. There is a slightly increasing trend in Chl-a concentrations in the northern Bering Strait (SECS). This increasing trend may be related to recent increases in the extent and duration of open waters due to the early break up of sea ice and the late formation of sea ice in the Chukchi Sea. 相似文献
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The foundations of offshore structures have been intensively studied to provide design guidelines for oil platforms. Recently, techniques developed for the oil industry have found new applications in the design of foundations for offshore wind turbines. There are simplified analytical solutions for the holding capacity of suction anchors, which are based on postulated failure mechanisms and are often compared with the results of finite element analyses. The merit of the results of a finite element analysis over the simplified solutions is that the finite element analysis satisfies all the basic equations in mechanics and does not require the assumption of reasonable failure mechanisms. The aim of this study is, based on the results of extensive finite element analyses, to provide a set of formulae for the estimation of the holding capacities of optimally loaded suction caisson anchors embedded in cohesive soils with a linear strength distribution. The bearing capacity factor and the depth of the optimal loading point are also estimated and reported. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Hydraulic Fracturing In Situ Stress Estimations in a Potential Geothermal Site,Seokmo Island,South Korea 总被引：1，自引：0，他引：1
Chandong Chang Yeonguk Jo Yangkyun Oh Tae Jong Lee Kwang-Yeom Kim 《Rock Mechanics and Rock Engineering》2014,47(5):1793-1808
We conducted hydraulic fracturing (HF) in situ stress measurements in Seokmo Island, South Korea, to understand the stress state necessary to characterize a potential geothermal reservoir. The minimum horizontal principal stress was determined from shut-in pressures. In order to calculate the maximum horizontal principal stress (S Hmax) using the classical Hubbert–Willis equation, we carried out hollow cylinder tensile strength tests and Brazilian tests in recovered cores at depths of HF tests. Both tests show a strong pressure rate dependency in tensile strengths, from which we derived a general empirical equation that can be used to convert laboratory determined tensile strength to that suitable for in situ. The determined stress regime (reverse-faulting) and S Hmax direction (ENE–WSW) at depths below ~300 m agrees with the first order tectonic stress. However the stress direction above ~300 m (NE–SW) appears to be interfered by topography effect due to a nearby ridge. The state of stress in Seokmo Island is in frictional equilibrium constrained by optimally oriented natural fractures and faults. However, a severe fluctuation in determined S Hmax values suggests that natural fractures with different frictional coefficients seem to control stress condition quite locally, such that S Hmax is relatively low at depths where natural fractures with low frictional coefficients are abundant, while S Hmax is relatively high at depths where natural fractures with low frictional coefficients are scarce. 相似文献
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