A Numerical Study on the Screening of Blast-Induced Waves for Reducing Ground Vibration   总被引：1，自引：1，他引：0  

Dohyun Park  Byungkyu Jeon  Seokwon Jeon 《Rock Mechanics and Rock Engineering》2009,42(3):449-473

Blasting is often a necessary part of mining and construction operations, and is the most cost-effective way to break rock, but blasting generates both noise and ground vibration. In urban areas, noise and vibration have an environmental impact, and cause structural damage to nearby structures. Various wave-screening methods have been used for many years to reduce blast-induced ground vibration. However, these methods have not been quantitatively studied for their reduction effect of ground vibration. The present study focused on the quantitative assessment of the effectiveness in vibration reduction of line-drilling as a screening method using a numerical method. Two numerical methods were used to analyze the reduction effect toward ground vibration, namely, the “distinct element method” and the “non-linear hydrocode.” The distinct element method, by particle flow code in two dimensions (PFC 2D), was used for two-dimensional parametric analyses, and some cases of two-dimensional analyses were analyzed three-dimensionally using AUTODYN 3D, the program of the non-linear hydrocode. To analyze the screening effectiveness of line-drilling, parametric analyses were carried out under various conditions, with the spacing, diameter of drill holes, distance between the blasthole and line-drilling, and the number of rows of drill holes, including their arrangement, used as parameters. The screening effectiveness was assessed via a comparison of the vibration amplitude between cases both with and without screening. Also, the frequency distribution of ground motion of the two cases was investigated through fast Fourier transform (FFT), with the differences also examined. From our study, it was concluded that line-drilling as a screening method of blast-induced waves was considerably effective under certain design conditions. The design details for field application have also been proposed.  相似文献   

Environment and mass dependencies of galactic λ spin parameter: cosmological simulations and observed galaxies compared     

B. Cervantes-Sodi  X. Hernandez  Changbom Park  Juhan Kim 《Monthly notices of the Royal Astronomical Society》2008,388(2):863-872

We use a sample of galaxies from the Sloan Digital Sky Survey (SDSS) to search for correlations between the λ spin parameter and the environment and mass of galaxies. In order to calculate the total value of λ for each observed galaxy, we employed a simple model of the dynamical structure of the galaxies, which allows a rough estimate of the value of λ using only readily obtainable observables from the luminous galaxies. Use of a large volume-limited sample (upwards of 11 000) allows reliable inferences of mean values and dispersions of λ distributions. We find, in agreement with some N -body cosmological simulations, no significant dependence of λ on the environmental density of the galaxies. For the case of mass, our results show a marked correlation with λ, in the sense that low-mass galaxies present both higher mean values of λ and associated dispersions, than high-mass galaxies. These results provide interesting constrain on the mechanisms of galaxy formation and acquisition of angular momentum, a valuable test for cosmological models.  相似文献   

Negative Impacts of Perkinsus olseni Infection in Manila Clam Ruditapes philippinarum Observed from Tidal Flats in Anmyeondo Island on the West Coast of Korea During Post-Spawning Period     

Lee  Hye-Mi  Park  Kyung-Il  Yang  Hyun-Sung  Choi  Kwang-Sik 《Ocean Science Journal》2021,56(3):307-316

Ocean Science Journal - The high load of protozoan parasites in marine bivalves often leads to mass mortalities of the hosts. On the west coast of Korea in the Yellow Sea, the protozoan parasite...  相似文献   

Day-Night and Gastrointestinal Changes in Winter Feeding Intensity and Prey Composition of Apogon lineatus Inhabiting the Southeastern Waters of Korea     

Park  Joo Myun  Jung  Hae Kun  Lee  Chung Il  Huh  Sung-Hoi 《Ocean Science Journal》2019,54(1):141-146

Ocean Science Journal - Diel and gastrointestinal changes in relation to the feeding intensity and prey composition of Apogon lineatus were investigated through the analysis of the diet contents of...  相似文献   

Tide-related Changes in mRNA Abundance of Aromatases and Estrogen Receptors in the Ovary and Brain of the Threespot Wrasse <Emphasis Type="Italic">Halichoeres trimaculatus</Emphasis>     

Dae-Ju Oh  Sung-Pyo Hur  Selma Bouchekioua  Yuki Takeuchi  Shingo Udagawa  Neelakanteswar Aluru  Yong-Ju Park  Ji-Gweon Park  Se-Jae Kim  Thomas W. Moon  Mathilakath M. Vijayan  Akihiro Takemura 《Ocean Science Journal》2018,53(2):239-249

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Changes in Fish Assemblages after Dike Construction in the Saemangeum Area     

Jeong-Hui Kim  Sang-Hyeon Park  Seung-Ho Baek  Min-Ho Jang  Ju-Duk Yoon 《Ocean Science Journal》2020,55(1):129-142

In the Saemangeum area, construction of a dike began in 1991 and was completed in 2006; desalination is currently being conducted. In order to investigate  相似文献   

Distribution and Sources of Dissolved and Particulate Heavy Metals (Mn,Co, Ni,Cu, Zn,Cd, Pb) in Masan Bay,Korea     

Park  Sojung  Choi  Mansik  Jang  Dongjun  Joe  Dongjin  Park  Kyunggue 《Ocean Science Journal》2020,55(1):49-67

Ocean Science Journal - In this study, we investigated the spatial and temporal distribution and sources of dissolved and particulate heavy metals in Masan Bay, an area that for a long time has...  相似文献   

A Review on Marine N2 Fixation: Mechanism,Evolution of Methodologies,Rates, and Future Concerns     

Bhavya  P. S.  Min  Jun-Oh  Kim  Min-Seob  Jang  Hyo Keun  Kim  Kwanwoo  Kang  Jae Joong  Lee  Jae Hyung  Lee  Dabin  Jo  Naeun  Kim  Myung Joon  Kim  Yejin  Lee  Junbeom  Lee  Chang Hwa  Bae  Hyeonji  Yoo  Hyeju  Park  Sanghoon  Yun  Mi Sun  Lee  Sang Heon 《Ocean Science Journal》2019,54(4):515-528

Ocean Science Journal - Investigations on marine N2 fixation have gained momentum since 1960s with eventual establishments of relevant methodologies to identify species involved and quantify the...  相似文献   

A comparison of network model creation algorithms based on the quality of wayfinding results     

Jinwoo Park  Daniel W. Goldberg  Tracy Hammond 《Transactions in GIS》2020,24(3):602-622

Various network model creation algorithms have been introduced to demonstrate a better approximation of the actual walking pattern and to provide a better wayfinding guide. However, it is under‐investigated which algorithm creates the most appropriate indoor navigation network model in the context of wayfinding applications. Due to the lack of discussion, some studies unconsciously extended an algorithm designed for creating an outdoor navigation network model to indoor space applications. This is problematic because indoor space has different spatial contexts from outdoor space, such as non‐linear space and no‐designated walking space. Our solution is to select five well‐known algorithms that have been introduced, to reproduce the algorithm for the automated construction of the indoor navigation network model, and to evaluate the applicability of algorithms for indoor wayfinding applications. This article compares the quality of wayfinding results from the output of the indoor navigation network model against two criteria: route efficiency (i.e., length) and route simplicity (i.e., number of directions). Our statistical analysis illustrates that the visibility graph algorithm is the most appropriate for indoor wayfinding applications.  相似文献   

Korean Global Data Assimilation and Prediction System     

Song-You Hong  Seon Ki Park  Rokjin Park  Jimy Dudhia 《Asia-Pacific Journal of Atmospheric Sciences》2018,54(1):265-265

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