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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Geoenvironmental Society
Journal Basic Information
Journal DOI :
Korean Geo-Environmental Society
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Volume & Issues
Volume 15, Issue 12 - Dec 2014
Volume 15, Issue 11 - Nov 2014
Volume 15, Issue 10 - Oct 2014
Volume 15, Issue 9 - Sep 2014
Volume 15, Issue 8 - Aug 2014
Volume 15, Issue 7 - Jul 2014
Volume 15, Issue 6 - Jun 2014
Volume 15, Issue 5 - May 2014
Volume 15, Issue 4 - Apr 2014
Volume 15, Issue 3 - Mar 2014
Volume 15, Issue 2 - Feb 2014
Volume 15, Issue 1 - Jan 2014
Selecting the target year
A Study on the Biogasification of Municipal and Industrial Wastewater Sludge
Kim, Jahyun ; Kim, Seogku ; Hwang, Injoo ; Ahn, Jaehwan ; Kang, Sungwon ; Lee, Wontae ; Lim, Junhyuk ; Lee, Jeakun ; Lee, Taeyoon ;
Journal of the Korean Geoenvironmental Society , volume 15, issue 9, 2014, Pages 5~12
DOI : 10.14481/jkges.2014.15.9.5
Anaerobic digestion was investigated for the stabilization of sludge, decrease of volatile solids, production of biogas for wastewater sludge. In this study, total solids and volatile solids, elemental analysis were conducted to determine characteristics of various types of sludges and investigate the feasibility of biogas production of Municipal Wastewater Sludge (MWS), Industrial Wastewater Sludge (IWS), mixed sludge (Mix), and Municipal Wastewater Sludg Cake (MWSC). Total solids, volatile solids, and C/N ratio were determined in the range of 11.2~20.6 %, 62.1~83.1 % of TS and 4.96~8.33 %. Using the biochemical methane potential (BMP test), mixed sludge and wastewater sludge finished the methane production within approximately 20 day and 16~17 day. Sludge cake finished within 10 day. Mixed sludge produced 395.5 mL
per g of Volatile Solid (VS) and resulted in the highest methane production. For carbon dioxide production, five sludges had similar value of accumulated carbon dioxide production except for sludge cake.
Characteristics for Co-digestion of Food Waste and Night Soil using BMP Test
Cho, Jinkyu ; Kim, Hyungjin ; Oh, Daemin ;
Journal of the Korean Geoenvironmental Society , volume 15, issue 9, 2014, Pages 13~18
DOI : 10.14481/jkges.2014.15.9.13
BMP test was carried out to evaluate the characteristics for co-digestion of night soil and food waste. 6 types of sludge were tested in 30 days which were raw, excess, digested, night soil/septic tank (1:1), food waste (food : dilution water = 1:1), and mixed sludge. Bio gas was produced actively after 2 days, and continued in 2 weeks. Gas generation amount was decreased rapidly after considerable space of time. Especially maximum productivity of gas was shown in 7~8 days. The ultimate methane yields of raw, excess, digested, night soil/septic tank, food waste, and mixed sludge were 64.63, 67.49, 66.45, 72.44, 107.85, and 46.71 mL
VS respectively from Modified Gompertz model. The lag growth phase time and maximum specific methane production rate of mixed sludge were 1.88 day and 80.4 mL/day respectively. The methane potential of mixed sludge was higher than individual sludge. So high methane potential was expected by controlling mixing ratio of food waste. Besides stable operation of digestion tank and the solution of oligotrophic problem were possible.
A Study on the Reasonable Application Method of Steel Fiber Reinforced Shotcrete in NATM Tunnel
Seok, Chongken ; Ahn, Taebong ;
Journal of the Korean Geoenvironmental Society , volume 15, issue 9, 2014, Pages 19~28
DOI : 10.14481/jkges.2014.15.9.19
Recently, the proportion of long tunnel has increased for efficient use of land due to limited land area, driving convenience and high speed. RMR and Q-System of empirical methods has been mainly used for tunnel support design in domestic. Although shotcrete is the key to NATM tunnel, the related studies are insufficient. So, steel fiber reinforced shotcrete is applied to II~V grade rocks on domestic and foreign applications. And same amount of shotcrete is equally applied to tunnel roof and wall regardless of the applied rock load. Shotcrete is applied excessively rather than the original proposed value of RMR and Q-System. Thus, this study is to reevaluate the application part of plain shotcrete and steel fiber reinforced shotcrete of tunnel in Daebo granite, and to propose the reasonable application method of steel fiber reinforced shotcrete. Field test and numerical back analysis using measurements were performed to verify stability. According to results, if RMR values are the upper class in the III grade, it can be designed in accordance with upper grade. In addition, if rock condition is good as a mountain tunnel in Daebo granite, it can be applied for plain shotcrete to III grade rocks because there is also no stability problems. And although steel fiber reinforced shotcrete is applied only crown of the tunnel in IV grade rocks, it is possible to secure stability for falling rock by key-block.
One Dimensional Seismic Response Analysis on Sub-ground of Architectural Heritage in Seoul, Korea
Jeon, Seongkon ; Kim, Dukmoon ; Kwon, Youngcheul ;
Journal of the Korean Geoenvironmental Society , volume 15, issue 9, 2014, Pages 29~36
DOI : 10.14481/jkges.2014.15.9.29
Under the situation that the seismic vulnerability are a worsening problem in many world's megacities, the disaster preparedness including earthquake hazards is a matter of primary concern in the capital city of Korea, Seoul. Especially, because it is hard to move or dismantle the architectural heritages, the mitigation of earthquake damages is potentially more difficult than other structures. Moreover, in order to decide the proper preparedness plan against future earthquakes, it is very important to understand how soils pass the seismic waves to architectural heritages. In this paper, therefore, the ground condition and depth of bedrock was investigated by the MASW-method at heritages located in Seoul. Then one-dimensional seismic response analysis was conducted based on the distribution of shear wave velocity. As the major result of analyses, peak acceleration, site amplification factor and natural period are proposed in each site for recurrence period.
Scour Monitoring for Offshore Foundation using Electrical Resistivity and Shear Wave Tomography
Park, Kiwon ; Lee, Jongsub ; Choi, Changho ; Byun, Yonghoon ;
Journal of the Korean Geoenvironmental Society , volume 15, issue 9, 2014, Pages 37~45
DOI : 10.14481/jkges.2014.15.9.37
An embedded length of monopile caused by a scouring should be evaluated to monitor the stability of offshore foundations, because offshore foundations are affected by horizontal load. The objective of this study is to evaluate the scouring around offshore foundation by using electrical resistivity and to estimate ground stiffness by using shear wave tomography. The electrical resistivity profiles and shear wave tomography were measured according to the scour depth of model ground prepared with sand and cement. Several electrodes and bender elements were used to measure the electrical resistivity and shear waves, respectively. The electrode sets are attached on the monopile surface and bender elements are arranged in
arrays by using nylone frames. The electrical resistivity profiles and shear wave tomography are acquired by laboratory experiment. Maximum scour depth was estimated by electrical resistivity profiles and the ground stiffness of model ground was estimated by shear wave tomography. This study suggests that the electrical resistivity profiles and shear wave tomography may be useful for monitoring the stability of the offshore foundations.
Design Load Analysis for Offshore Monopile with Various Estimation Methods of Ground Stiffness
Jang, Youngeun ; Cho, Samdeok ; Choi, Changho ;
Journal of the Korean Geoenvironmental Society , volume 15, issue 9, 2014, Pages 47~58
DOI : 10.14481/jkges.2014.15.9.47
This study explores methods for modeling the foundation-seabed interaction needed for the load analysis of an offshore wind energy system. It comprises the comparison study of foundation design load analyses for NREL 5 MW turbine according to various soil-foundation interaction models by conducting the load analysis with GH-Bladed, analysis software for offshore wind energy systems. Furthermore, the results of the aforementioned load analysis were applied to foundation analysis software called L-Pile to conduct a safety review of the foundation cross-section design. Differences in the cross-section of a monopile foundation were observed based on the results of the fixed model, winkler spring and coupled spring models, and the analysis of design load cases, including DLC 1.3, DLC 6.1a, and DLC 6.2a. Consequently, under all design load conditions, the diameter and thickness of the monopile foundation cross-section were found to be 7 m and 80 mm, respectively, using the fixed and coupled spring models; the results of the analysis conducted using the winkler spring model showed that the diameter and thickness of the monopile foundation cross-section were 5 m and 60 mm, respectively. The study found that the soil-foundation interaction modeling method had a significant impact on the load analysis results, which determined the cross-section of a foundation. Based on this study, it is anticipated that designing an offshore wind energy system foundation taking the above impact into account would reduce the possibility of a conservative or unconservative design of the foundation.
Effect of Anti-washout Admixture Implementation on Backfill Aggregates on Underwater Structures
Kim, Ukgie ; Choi, Changho ; Park, Bonggeun ; Li, Zhuang ; Cho, Samdeok ;
Journal of the Korean Geoenvironmental Society , volume 15, issue 9, 2014, Pages 59~67
DOI : 10.14481/jkges.2014.15.9.59
With increasing underwater structure construction, there is high interest in offshore foundation and underwater grout and various study has been done in this area. For grout materials constructed underwater, it may be washed away by water or easily disturbed and material separation phenomenon during curing period always happens. As a result, it is difficult to ensure construction quality and this has a significant influence on the design strength of structure. In this study, to understand application effects of anti-washout admixture for the preplaced construction method, where grout is injected in monopile after filled with aggregates, laboratory tests on bleeding and compressive strength of anti-washout admixture were performed under various test conditions varying size of aggregate, water and cement ratio and admixture, and test results were compared and evaluated.
Laboratory and Full-scale Testing to Investigate the Performance of Rock Fall Protection System with Hexagonal Wire Net
Youn, Ilro ; Oh, Sewook ; Kwon, Youngcheul ;
Journal of the Korean Geoenvironmental Society , volume 15, issue 9, 2014, Pages 69~75
DOI : 10.14481/jkges.2014.15.9.69
Rock fall protection system installed against rock slope is one of the most conventional way to protect nearby infra structures. Despite of wide application of typical rectangular nets, virtually installed to protect rock slope face, several problems have also been pointed out up to date. Rectangular draped nets are vulnerable to a sudden external shock such as rock fall, because it doesn't have any systematical buffers or shock absorbers. Furthermore, it has been widely recognized from the some cases of rock fall accident in Korea that rock fall protection nets cause wide range of failure in the rock slope faces due to insufficient pullout bearing capacity of fixing parts. Therefore, in this study, we tried to make a consideration about the problems of existing standard rock fall protection nets in Korea, and develop a new type of hexagonal net with a shock absorber based on design rock fall energy. In this paper, laboratory and full scale test procedure is described to analysis the performance of newly developed hexagonal rock fall net, and the key results are presented and discussed.
Development of Integrated Management System for Steep Slope Prevention and Management
Lee, Kyungchul ; Jang, Yonggu ; Song, Jihye ; Kang, Injoon ;
Journal of the Korean Geoenvironmental Society , volume 15, issue 9, 2014, Pages 77~85
DOI : 10.14481/jkges.2014.15.9.77
Recently, the National Emergency Management Agency of Korea has been operating the National Disaster Management System. Nevertheless, there are numerous difficulties in systematic controlling the steep slope DB promptly, because the system's functions in input and control for steep slope information are merely simple. Futhermore, the hazard degrees of steep slope lands nowadays have risen suddenly in accordance with the increase rate of large scale landslides such as the landslide cases of Umyeonmountain, Chuncheon province and others or sever rain storm cases. these lead to rapid increases in frequencies of nature disasters nationally. therefore, it is needed to develop the GIS-based integrated management system for steep slope information in order to manage disasters in advance or high-degree control. This study shows the national GIS-based integrated management system to prevent the disasters that caused by steep slope lands. The integrated management system developed in this study consists of surface information input modules, realtime DB liaison modules of integrated underground information, V-world background map-based GIS, integrated management system for steep slope information user modules, realtime liaison interface modules designed for utilizing steep slope information. Also, tests about stability of data storage, system stability and consistency of processing speed were performed.
The Evaluation of Bearing Resistance of Underreamed Ground Anchor through Realistic Model Experiments
Min, Kyongnam ; Lee, Jaewon ; Lee, Junggwan ; Lee, Dongwon ; Jung, Chanmuk ;
Journal of the Korean Geoenvironmental Society , volume 15, issue 9, 2014, Pages 87~92
DOI : 10.14481/jkges.2014.15.9.87
The Ground anchor is reinforcement to resist pull-out through ground that is used supports structure. The pull-out resistance of anchor is constructed by skin friction resistance from compression borehole wall in expanded wings and bearing pressure from the ground. Especially, underreamed ground anchor is reinforcement that adopts active reinforcement to prevent deformation of ground using bearing resistance generated reaming anchorage. This study is conducted to calculate bearing resistance of underreamed ground anchor. Realistic model tests were fulfilled to determine bearing resistance of anchor, and correlate results of tests to Uniaxial Compressive Strengths (UCS) of ground models that assumed weathered rock condition in 8 case. In a comprehensive series of the tests, the bearing resistances were measured by pull-out tests. The bearing resistances derived from tests have a linear correlation with UCS. We also suggest empirical equation between bearing resistance and UCS of rocks by single linear regression analyses. In test results of this study, the bearing resistances were evaluated approximately 13 times higher than UCS of the grounds, and it is qualitatively similar to numerical values of pull-out force derived from theory.