• Title/Summary/Keyword: soil improvement

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A Study on the Increase of Bearing Capacity of Soft Ground in Shallow Foundation Using High Density Rapid Expansion Material (고밀도 급속 팽창재를 이용한 얕은기초 연약지반의 지내력 증대에 관한 연구)

  • Ro, Euichul;Kim, Daehyeon
    • The Journal of Engineering Geology
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    • v.30 no.2
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    • pp.185-198
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    • 2020
  • High-density rapid expansion material is a method that increases the solid volume of injection materials due to hydration and foam reactions at the same time as spraying. It is an effective method for securing ground stability, restoring subsidence, and loading during construction of structures. In this regard, through the mechanical experiments of injection materials, the stability of the foundation ground of the structure and the effect of increasing the endurance using site construction were analyzed. The results of the experiment showed that the unit weight of soil decreased by 10.5% after injection of the filling material, and the allowable support for the structure was deemed safe, and the subsidence by each section after ground improvement was determined to be safe at 2.28, 1.55 and 0.46 cm, respectively, with an acceptable subsidence of less than 5 cm. After the field test, five inclinometers were installed on the top floor of the target building to measure the displacement of the X and Y axes. As a result of the measurement, no displacement related to the phenomenon of inequality or subsidence cracks of the structure was measured for about 16 months (509 days) after construction. This can be judged to be a sufficient increase in the stability of the ground after the injection of rapid expansion.

A Study on the Reinforcement and Environmental Impact of LW Injection (LW주입에 의한 지반보강 및 환경영향성에 관한 연구)

  • Chun, Byungsik;Do, Jongnam;Sung, Hwadon;Lim, Jooheon
    • Journal of the Korean GEO-environmental Society
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    • v.7 no.6
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    • pp.121-131
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    • 2006
  • This study is performed to examine the ground reinforcement effect and the environmental impact of LW injection, which is widely used during the excavation of high-rise apartment buildings. In addition, it proved that by conducting field exploration and laboratory test the engineering ground reinforcement effect of LW injection in the ground has low coefficient of permeability. The environmentally friendly aspect was evaluated through an assessment of environmental impact. The results of laboratory test shows that LW coagulating material with SC type soil structure has significant improvement of uniaxial compressive strength, increasing by three times and the shear strength increasing by twice, coefficient of permeability decreasing six to seven times. And the result of environmental impact tests show that from 6 hour after where the pH increases until 7.96 to initially it diminished, it started and to 80 hour after it recovered a pH 7.25 initially with 7.30. The chemical composition analysis test result that unpolluted water and polluted water hydrogen ion concentration (pH) show that the unpolluted water pH 7.36, polluted water pH 7.85, which is inside the Ministry of Environment standard of drinking water (the pH 5.8~8.5). The assessment of environmental impact and chemical analysis test also demonstrate that the LW coagulating material is environmentally friendly. In the $Cr^{6+}$ and the salinity detection test, it was proven that the salinity is slight and the $Cr^{6+}$ is not detected.

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Aromatic Constituents and Essential Oil Content of Codonopsis lanceolata Trautv Cultivated at Different Altitudes (표고에 따른 더덕의 향기 성분과 정유 함량)

  • Kim, Sang-Kuk;Kang, Dong-Kyoon;Min, Gi-Gun;Chung, Sang-Hwan;Lee, Seong-Phil;Lee, Sang-Chul;Choi, Boo-Sull
    • Korean Journal of Medicinal Crop Science
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    • v.7 no.1
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    • pp.58-62
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    • 1999
  • This study was to determine aromatic constituents and essential oil content in the root of Codonopsis lanceolata grown at different altitudes; Andong(150m), Mt. Hagka(550m) and Mt. Irwol(750m). Soil pH in Mt. Hagka and Mt. Irwol was 5.6 and 6.1, respectively, which was lower than in Andong(150m), but organic matter content was higher than that of Andong with 6.7 to 8.8%. Fresh root yield also increased as cultural region was located at higher altitude. In particular, yield in Mt. Irwol was 281kg/10a. Essential oil content was highest of 0.006% in the Mt. Irwo1. Forty-eight volatile aromatic compounds in the root of Codonopsis lanceolata were identified by GC/MS. Major aromatic compounds were 1-hexanol, cis-3-hexano1. and Trans-2-hexanol. In partucular, Trans-2-hexanol, was highest in Mt. Irwol attaining the 47.22% area. As a result, it was considered that cultural region above 700m in altitude was the most effective for the improvement of essential oil and aromatic constituents in the roots of Condonopsis lanceolata Trautv.

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Characteristic of Permeability with the Sand, Calcium Bentonite and Solidifier Mixtures according to Selective Reaction of TCE (트리클로로에틸렌(TCE) 선택적 반응에 따른 모래, 칼슘-벤토나이트 및 겔화제 혼합차수물의 투수 특성)

  • Yun, Seong Yeol;Choi, Jeong Woo;Oh, Minah;Lee, Jai-Young
    • Journal of the Korean Geosynthetics Society
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    • v.19 no.1
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    • pp.25-33
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    • 2020
  • To improvement the swelling characteristics of the existing cutoff wall against the moisture, the permeability of the sand, calcium bentonite and solidifier mixture according to the contact with trichloroethylene (TCE) was evaluated. Characteristics analysis and the permeability test of the research materials were performed. The permeability was decreased as the mixing ratio of the calcium bentonite was increased and it was increased as the mixing ratio of the solidifier was increased. In conclusion, when mixing 15% of calcium bentonite and more than 30% of solidifier, the permeability coefficient in the underground water movement was analyzed as more than α × 10-4 cm/sec showing that it does not block the underground water movement. In addition, as the permeability coefficient of mixtures after TCE reaction was analyzed as less than α ×10-7 cm/sec, it satisfied the condition of blocking layer (less than 1.0 × 10-6 cm/sec). Therefore, the calcium bentonite and solidifier can be utilized as barrier that showing the characteristic of percolation ability conversion in soil and underground water contaminated with TCE.

The Review of KDAB Agriculture Project for the Rural Development in Bangladesh (방글라데쉬 농촌 개발을 위한 케이디에이비 농업 개발사업의 평가)

  • Kwon, Byung-Hee
    • Journal of Agricultural Extension & Community Development
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    • v.3 no.2
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    • pp.197-209
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    • 1996
  • Bangladesh that is known as the poorest country of the world has the large land of fertile soil and very good environment to live, even though we think she may be very bad to live. People being habituated to that good environment, the population explosion made the people to be starven, but the treatment has been simple support without deep analysis of the root of poverty. As the result it is general that the poverty is severer and severer in spite of continuous support. For the last century Korea changed from the country of poverty and despair to that of development and hope, to be model mid vision of under development countries including Bangladesh. At this point it is necessary to look back the way of development to help them to solve their poverty problem. That is the goal of this project, and this thesis is the result of it. It is evaluated for the 1st 5 years work of the project to apply the result to the next 5 years plan. This project had been proceeded from 1. Jul. 1990 to 30. Jun. 1995 at Chilmari area of Bangladesh, with teaching and training to wake up the mentality of the people, demonstration farming and cooperative association. It was proceeded as the Agriculture project of KDAB(Korean Development Association in Bangladesh, an NGO registered to Bangladesh) supported by Good Neighbors, KOICA and many churches and individuals. Especially the teaching and training work was proceeded as the branch of the Canaan Farmer`s School of Korea with instruction and support. After the basic survey for project, the confirmation of working place and the preparation of training facility, 10 times of long term training(3 months worse, boarding) was completed, with many times of short term training, informal training, demonstration farm, various demonstrating works. The results of the work are understanding of the not of problem by participatory observation, making plan to solve it, getting the trust from the people and beginning the practical work with the trainees for development of economy and living situation. The biggest problem of Bangladesh is being understood losing the desire to solve the poverty problem and the self-confidence to be able to do it. It is the conclusion that after solving the problem of thought and mentality, the education, technology and money can be effective for development. So the 1st 5 year project is evaluated as the basic work to analyse the root of problem, to chance mentality of people and to search income source. The next goal is to promote practical living level of people. For that it is necessary to develope die mentality of people including responsibility and self-confidence by teaching and training, to educate cooperative association and technology for economical development, to proceed integrated rural development work with economical development, educational improvement and reformation of environment. It is very important result that they decided to grow poultry for main economical source of Chilmari area, to do economical development work by joint operation of poultry through cooperative association.

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Influence of the application of Tithonia diversifolia and phosphate rocks on the performances of rainfed rice

  • Rusaati, Butoto Imani wa;Kang, Jun-Won;Gendusa, Patience Arusi;Bisimwa, Pacifique Bulakali;Kasali, Joseph Lumande;Rolly, Nkulu Kabange;Park, Joowon;Rehema, Esther Matendo;Ndabaga, Cephas Masumbuko;Kaboyi, Gentil Iragi;Nankafu, Orleanne Nangalire;Chirimwami, Anastasie Bahati
    • Korean Journal of Agricultural Science
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    • v.47 no.3
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    • pp.403-414
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    • 2020
  • Gradient concentrations of Tithonia diversifolia green leaves and phosphate rocks were used to investigate their contributions as a fertilizer to the yield and quality improvement of a rainfed rice cultivar. Six treatments were compared: (1) T0, no fertilization (control); (2) T1, 1.28 g of phosphate rocks; (3) T2, 250 g of organic matter; (4) T3, 500 g of organic matter; (5) T4, 250 g of organic matter + 1.28 g of phosphate rocks; (6) T5, 500 g of organic matter + 1.28 g of phosphate rocks. The results showed that the germination percentage recorded 15 days after sowing varied from 58 - 76% between T0 and T5. The number of panicles ranged between 2 (T0) to 6.3 (T5). Moreover, the recorded length of the panicles ranged between 7.5 (T1) to 15.8 cm (T2), and the number of grains per panicle ranged between 25.5 (T1) to 273.5 (T3). The plant height was significantly increased in the T5 (79.27 cm) group compared to the T1 (33.63 cm) and control treatment (T0) (40.08 cm) groups. Although the plant height in the T2, T3, and T4 groups was slightly lower than the T5 group, the difference was not statistically significant. The average of the grain number per plant was high in the T3 (273.6 grains) group compared to the T1 and T0 (25.5 and 32.8 grains) groups, respectively. These results suggest that the combination of T. diversifolia leaves and phosphate rocks as a natural fertilizer would be beneficial when integrated into soil fertility management strategies and would contribute to improving crop yield and quality.

Analysis of Group Attitudes toward the Development Plan of the Sobaeksan Jarak-gil Ecological Traill (소백산 자락길 생태탐방로 개발계획에 대한 각 집단 태도분석)

  • Park, Kum-Mi;Jung, Tae-Yeol
    • Journal of the Korean Institute of Landscape Architecture
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    • v.42 no.2
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    • pp.41-51
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    • 2014
  • A self-administered questionnaire survey and face-to-face interviews were conducted on 150 local residents belonging to seven villages, 160 visitors and 86 experts in order to analyze the attitudes of groups of local residents, visitors as well as experts toward the development plan of Sobaeksan Jarak-gil. Reliability analysis and one-way ANOVA were performed on the data collected by a questionnaire survey using IBM SPSS Statistics 20.0 after coding. The Duncan Test was conducted as a post-hoc test. Based on the analytical results, in economic terms, the expert group expected an increase in income, improvement in living standards and increase in expenditure for the maintenance of local infrastructure. In environmental terms, the visitor group was highly concerned about the disruption of the local natural environment and ecosystem, destruction of local properties and landscape, increase in water/soil/air pollution and increase in solid waste and noise. In social and cultural terms, the expert group had higher expectation for excavation of traditional cultural properties, instillation of local patriotism and pride, and the visitor group was highly concerned about a rise in crime, destruction of indigenous culture/increase in imitations, and induction of conflicts between residents. It is estimated that these results will be used as basic data for establishing the development plan of the mountainous ecological trail reflecting opinions of various groups.

Evaluation of Wildlife Crossings Eeffectiveness on Use Frequency and Diversity Indicators of Wildlife (야생동물 이용빈도 및 종다양도를 활용한 생태통로 효율성 평가)

  • Woo, Donggul;Seo, Hyunjin;Park, Taejin;Song, Euigeun;Kim, Kyungmin;Choi, Taeyoung
    • Journal of Environmental Impact Assessment
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    • v.28 no.6
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    • pp.525-535
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    • 2019
  • In this study, 49 major WCS(Wildlife Crossing Structure), including Baekdu-daegan, were evaluated for the effectiveness of WCS on using the daily average frequency index and diversity Index comparing the number of species that appear with the surrounding habitats. According to the analysis, the average use frequency of the entire WCS was 1.4 times, and the average number of WCS exceeded the average was 17 and 34.7 percent of the total. There were 18 WCS with the same number of habitats and species that appeared in the same area, or 36.7 percent of the total. The daily average use frequency and variety were all analyzed at 10 efficient WCS, accounting for 20.4 percent of the total. According to the results of an site survey on the compliance rate of 4 efficient WCS, the compliance rate of the Deoksanjae overpass was the best in location selection, specifications, vegetation cover and soil, fence. The results of this research will be used as basic data for the study of WCS effectiveness, including the improvement of functions of new and installed WCS.

Economical Feasibility of the Treatment Methods of the Dredged Sediments from Contaminated Agricultural Reservoirs (농업용 저수지 준설토의 처리 공법에 따른 경제성 분석)

  • Oh, Kyoung-Hee;Cho, Young-Cheol
    • Journal of Korean Society of Environmental Engineers
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    • v.35 no.10
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    • pp.756-762
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    • 2013
  • The economical feasibility was conducted to find the adequate method to treat the dredged sediments from agricultural reservoirs in a pilot project that had been operated to improve the quality of water and benthic environments by dredging of contaminated sediments. For benefit/cost (B/C) analysis, the net expenses were considered as the costs of project, and the benefits were calculated from the saving of waste-treatment cost through reuse of dredged sediment, the saving of construction cost of settling pond, and the values of retained water by dredging. Although the economic feasibility depended on the sites of operation, the average B/C value of the pilot project was estimated as 1.32, indicating this project is economically feasible. Depending on the treatment methods, the B/C values were in the order of the methods of coagulating sedimentation, machinery dewatering, stabilization through exothermic reaction, and soil improvement and stabilization. The machinery dewatering method is estimated as the most adequate one to treat the dredged sediments because of the minimum riskiness of secondary pollution, the recyclability, and its economic feasibility.

Development of Evaluation Method for Environmental Friendly Property in National Highway (일반국도의 환경친화성 평가방법론 개발)

  • Jeon, Woo-Hoon;Lee, Young-Ihn
    • International Journal of Highway Engineering
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    • v.12 no.3
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    • pp.87-92
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    • 2010
  • As the Concept "how environmental friendly" becomes more and more important in road construction. However, so far there is no estimation method. Environmental friendly concept can be incorporated at the plan level in order to influence decision making, and support policies that affect environment. The overall goal of this study was to develop environmental friendly concept measures for the national highway and to develop a methodology to implement a more environmental friendly concept. The research identified 8 performance measures through a project analysis that could address environmental impact assessment system's ten strategic goals - Topography, Wildlife, hydrology, landuse, air quality, water quality, soil, waste, noise, landscape. The qualitatively and quantitatively evaluation approach was selected as the decision support framework and performance measure were investigated using the AHP(Analytic Hierarchy Process) and pilot corridor for a 10 section and calculate the index values. The methodology was applied to a pilot corridor comprised of a 120km section of national highway in korea. The methodology made it possible to identify the specific performance measures that need improvement to enhance the overall environmental friendly concept. It is fairly intuitive, based on readily available data, and is easy to apply. It provides a powerful tool for government to assess the relative environmental friendly conceptof their transportation corridors now and in the future. It allows for comparisons within a corridor and with other corridors and identifies the improvements needed to enhance the environmental friendly concept.