A new rock mass failure criterion for biaxial loading conditions   总被引：1，自引：0，他引：1  

P. H. S. W. Kulatilake  Jinyong Park  Bwalya Malama 《Geotechnical and Geological Engineering》2006,24(4):871-888

To simulate brittle rocks, a mixture of glastone, sand and water was used as a model material. Thin galvanized sheets of thickness 0.254 mm were used to create joints in blocks made out of the model material. To investigate the failure modes and strength, both the intact material blocks as well as jointed model material blocks of size 35.6 × 17.8 × 2.5 cm having different joint geometry configurations were subjected to uniaxial and biaxial compressive loadings. A new intact rock failure criterion is proposed at the 3-D level. This criterion is validated for biaxial loading through laboratory experimental results obtained on intact model material blocks. Results obtained from both the intact and jointed model material blocks are used to develop a strongly non-linear new rock mass failure criterion for biaxial loading. In this failure criterion, the fracture tensor component is used to incorporate the directional effect of fracture geometry system on jointed block strength. The failure criterion shows the important role, the intermediate principal stress plays on rock mass strength.  相似文献   

The influence of context on lifeline behavior: Local policies under wind storm and earthquake scenarios     

Dorothy Reed  Jane Preuss  Jaewook Park 《Natural Hazards》2006,39(2):289-307

Local policies can play an important role in establishing a context that shapes vulnerability and influences subsequent recovery of lifelines under the natural hazards of extreme wind and seismic events. External factors, such as access availability, have long been known to influence the rate of restoration of utility systems following blackouts. Thus, since system performance takes place within a socio-technical-political context, it can be anticipated that selected local policies may also influence either the geographic extent of damage or the rate of restoration or both. This project empirically validates the assumption that selected local non-design policies establish a context that significantly (measurably) influences system functionality in terms of spatial extent and duration of outage.  相似文献   

Reevaluation of mixing among multiple water masses in the shelf: An example from the East China Sea     

L. Zhang  Z. Liu  J. Zhang  G.H. Hong  Y. Park  H.F. Zhang 《Continental Shelf Research》2007

East China Sea (ECS) is bounded by the continent where the fourth largest river of Changjiang discharges large amounts of freshwater to the west and by the Kuroshio in the East and connected to the South China Sea via Taiwan Strait, therefore water characteristics are very complex and undergo great seasonal changes. The dominant source waters in the ECS are found to be Kuroshio Surface Water (KSW), Kuroshio Sub-surface Water (KSSW), Changjiang Diluted Water (CDW), and Taiwan Strait Warm Water (TSWW). Optimum multiparameter analysis (OMP) using temperature, salinity and ²²⁶Ra were applied to quantify the contribution of individual source water to the surface water of the ECS in summer. The successful application of radium isotope in OMP analysis demonstrates the usefulness of ²²⁶Ra in the discrimination of mixing among multiple water sources. In 1987, one interesting phenomenon was that the KSSW entered the surface with the upwelling at the margin of continental shelf, and affected the coastal water obviously. In 1999, the TSWW extended northward continuously up to the Changjiang Estuary.  相似文献   

Use of a forensic geochemical technique and a hydrogeological assessment to determine the source of petroleum hydrocarbon contamination at a foreshore site in Korea     

Jeong Jun Park  Hyung Jin Kim 《Environmental Earth Sciences》2018,77(21):742

Investigations undertaken in 2013 at a foreshore site that was historically used for ship repairs in Korea indicated that soil and groundwater were contaminated with petroleum hydrocarbons over an area of 10,000 m². Groundwater investigations and modelling were undertaken to determine the characteristics of aquifers beneath the site, including the direction and rate of groundwater flow and the extent of dispersion of total petroleum hydrocarbon contamination. To identify petroleum products residing in contaminated soils, the hump of an unresolved complex mixture on the baseline found in the data of gas chromatography was used as a new method. Based on objective facts obtained from basic investigation, the current state of contamination, and discrimination of oil species, the polluter as specified in the Korean Soil Environment Conservation Act was identified.  相似文献   

Dynamics of ecosystems and anthropogenic drivers in the Yellow Sea Large Marine Ecosystem   总被引：1，自引：0，他引：1  

Jun Sun  Yinfeng Guo  Gyung Soo Park  Andrew Hudson 《海洋学报(英文版)》2022,41(6):1-2

<正>In the developed world, governance of marine ecological environment is the important part of the national ecological and economic outcome. The Yellow Sea is one of large marine ecosystems in the seas of East Asia, which is an extension of one of the largest continental shelf areas, and forms a huge but shallow sediment body in its south area which is geographically unique in the world. As a region with the most fragile natural environment, unparalleled global ecological significance and...  相似文献   

Winter distribution of diatom assemblages along the coastline of R. O. Korea in 2010     

Joon Sang Park  Kyun-Woo Lee  Seung Won Jung  Taek-Kyun Lee  Hyoung Min Joo 《海洋学报(英文版)》2022,41(6):68-77

Diatoms are a globally successful and eukaryotic photosynthetic organism with an ornamented silica external wall. The relationship between their valve morphology and habitat means that diatoms can be used as bioindicators to characterize the aquatic environment. To estimate the differential distribution and diversity of diatom assemblages along the coastal line, we collected phytoplankton samples from 114 coastal sites of waters of R. O. Korea. We applied the unweighted pair-group technique usin...  相似文献   

Dissolved Pb Concentrations and Stable Pb Isotope Ratios in the Ulleung Basin,East/Japan Sea     

Choi  Seonghu  Choi  Man-Sik  Joe  Dongjin  Park  Sojung  Kim  Jinwoo  Ra  Kongtae  Kim  Intae  Kim  Kyung-Tae  Lee  Kyoung-Seok  Lim  Jean-Sun 《Ocean Science Journal》2022,57(3):436-450

Ocean Science Journal - The spatial distributions of dissolved lead (Pb) concentrations and stable Pb isotope ratios in the Ulleung Basin, East/Japan Sea, were investigated to identify the Pb...  相似文献   

Contributions of solar and greenhouse gases forcing during the present warm period     

Hyung-Gyu Lim  Sang-Wook Yeh  Ji-Won Kim  Rokjin Park  Chang-Keun Song 《Meteorology and Atmospheric Physics》2014,126(1-2):71-79

Due to the dramatic increase in the global mean surface temperature (GMST) during the twentieth century, the climate science community has endeavored to determine which mechanisms are responsible for global warming. By analyzing a millennium simulation (the period of 1000–1990 ad) of a global climate model and global climate proxy network dataset, we estimate the contribution of solar and greenhouse gas forcings on the increase in GMST during the present warm period (1891–1990 ad). Linear regression analysis reveals that both solar and greenhouse gas forcing considerably explain the increase in global mean temperature during the present warm period, respectively, in the global climate model. Using the global climate proxy network dataset, on the other hand, statistical approach suggests that the contribution of greenhouse gas forcing is slightly larger than that of solar forcing to the increase in global mean temperature during the present warm period. Overall, our result indicates that the solar forcing as well as the anthropogenic greenhouse gas forcing plays an important role to increase the global mean temperature during the present warm period.  相似文献   

Vitellogenin gene characterization and expression of Asian paddle crabs (Charybdis japonica) following endocrine disrupting chemicals     

Kiyun Park  Tae-Soo Kwak  Ihn-Sil Kwak 《Ocean Science Journal》2014,49(2):127-135

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Marine biological feedback associated with Indian Ocean Dipole in a coupled ocean/biogeochemical model     

Jong-Yeon Park  Jong-Seong Kug 《Climate Dynamics》2014,42(1-2):329-343

The impact of marine ecosystem on the tropical climate variability in the Indian Ocean is investigated by performing coupled ocean/biogeochemical model experiments, which are forced by realistic surface winds from 1951 to 2010. Results from a suite of chlorophyll perturbation experiments reveal that the presence of chlorophyll can have significant effects on the characteristics of the Indian Ocean Dipole (IOD), including its amplitude and skewness, as well as on the mean state. Specifically, chlorophyll increases mean sea surface temperature due to direct biological heating in regions where the mean mixed layer depth is generally shallow. It is also found that the presence of chlorophyll affects the IOD magnitude by two different processes: One is the amplifying effect by the mean chlorophyll, which leads to shoaling of mean thermocline depth, and the other is the damping effect by the interactively varying chlorophyll coupled with the physical model. There is also a biological impact on the skewness of the IOD, resulting in enhanced positive skewness. This skewness change is primarily caused by the phase dependency of the above two contradicting effects involving the asymmetric thermocline feedback and the nonlinear mixed layer heating.  相似文献