• 한국해양공학회지
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• 제20권4호
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• pp.43-49
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• 2006

Detailed investigations were carried out on the stability of the dredged soil bed against wave actions, aimedat establishing the design method of artificial tidal flats using dredged soil. The soil was dredged at Nagoya port, Japan, and has a mean grain size of 0.013mm. Basic features of artificial dredged soil bed against wave actions were explained from a series of model experiments in a wave flume. The two types of section shapes were employed; one is a horizontal bed and the other is a sloped one. Changes of the bed profile, shear strength, grain size distribution and water content, according to the wave actions, were measured in detail. The cumulative effect of the wave actions, over about one week, was investigated. A dredged soil bed moves withthe wave actions with relatively small wave height. It should be especially. noted that the clay component is dissolved and flown out, away from the surface layer, and consequently the surface layer hardens, as if it is covered with sand. Wren the wave height is gradually increased, the bed is not liquefied and the shear strength of the dredged bed is increased by a wave-induced dissipation of pore pressures in the bed and a decrease of clay component by the wave-induced leakage.

• 한국조경학회지
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• 제25권2호
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• pp.94-103
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• 1997

The purpose of this study is to find out the effects of brick paved under-surface soil physical properties which are changed by fixed trampling. Thus, a sandy loam which is known as a profitable soil for plants is used an experimental soil to study the changes of the soil physical properties. It is related to sand bed's thickness & particle size which are settled by experimental variable factors. According to the variation of sand bed's particle size, bulk density and soil hardness at natural dryed soilcondition result in 0.075~2.00mm>2.00~5.00mm>2.00~8.00mm>5.00~8.00mm, and water content at natural dryed soil condition are observed being insensible change rate from the point that sand thickness is 30~40mm and more sand bed's thickness constructed by the variation of sand bed's thickness.

• Journal of Ship and Ocean Technology
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• 제1권1호
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• pp.35-47
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• 1997

The consequences associated with ships running aground depend very much on the soil characteristics of the sea bed and the geometrical shape of the ship bow. The penetration into the sea bed depends on these factors and the penetration is an important factor for the ship motion because it influences the ship heave and pitch motions as well as the friction between the ship and the soil. In this paper a rational calculation model is presented for the sea bed soil reaction forces on the ship bottom. The model is based on the assumption that the penetration of the ship bow generates a flow of pore water through the grain skeleton of the soil. The flow is governed by Darcy\`s law and it is driven by the pressure of the pore water at the bow. In addition to this pore water pressure, the bow is subjected to the effective stresses in the grain skeleton at the bow surface. These stresses are determined by the theory of frictional soils in rupture. Frictional stresses on the bow surface are assumed to be related to the normal pressure by a simple Coulomb relation. The total soil reaction as a function of velocity and penetration is found by integration of normal pressure and frictional stresses over the surface of the bow. The analysis procedure is implemented in a computer program for time domain rigid body analysis of ships running aground and it is verified in the paper through a comparison of calculated stopping lengths, effective coefficients of friction, and sea bed penetrations with corresponding experimental results obtained by model tests as well as large, scale tests.

• 한국연안방재학회지
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• 제5권4호
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• pp.163-172
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• 2018

To propose the design technique and the execution manual of the LWFS(Lightweight Foamed Soil) method using dredged soil, the operation system for the test-bed integrated management, and to establish an amendment for the domestic quantity per unit and specifications, and a strategy for its internationalization. In order to utilize the dredged soil from the coastal area as a construction material, we constructed the embankment with LWFS on soft ground and monitored its behavior. As a result, it can be expected that the use of LWFS as an embankment material on the soft ground can improve the economic efficiency by reducing the depth and period of soil improvement as well as the uses of nearby dredged soil. To verify the utilization of the dredged soil as a material for light-weighted roadbed, soft ground and foundation ground, and surface processing, perform an experimental construction for practical structures and analyze the behavior. It is expected to be able to improve the soft ground with dredged soil and develop technique codes and manuals of the dredged soil reclamation by constructing a test-bed in the same size of the fields, and establish the criteria and manual of effective dredged soil reclamation for practical use. The application technology of the dredged soil reclamation during harbor constructions and dredged soil reclamation constructions can be reflected during the working design stage. By using the materials immediately that occur from the reclamation during harbor and background land developments, the development time will decrease and an increase of economic feasibility will happen. It is expected to be able to apply the improved soil at dredged soil reclamation, harbor and shore protection construction, dredged soil purification projects etc. Future-work for develop the design criteria and guideline for the technology of field application of dredged soil reclamation is that review the proposed test-bed sites, consult with the institutions relevant with the test-bed, establish the space planning of the test-bed, licensing from the institutions relevant with the test-bed, select a test-bed for the dredged soil disposal area.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회 2차
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• pp.192-199
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• 2010

This research produced internal model tester ($2.0m{\times}2.0m{\times}1.0m$) to evaluate the field application of Paju Unjeong District water recycling system for small streams eco-friendly river bed disparity method for the first time in Korea and conducted comparative analysis of the Paju Unjeong District water recycling system field test results and infiltration rate result of internal tests by each rainfall intensity following surface material. Infiltration rate result of internal tests concrete pavement by rainfall intensity following surface material, asphalt pavement, bentonite mate, stabilized soil construction and mixed soil construction manifested low infiltration rate. On the contrary, compaction soil, grassland and water permeable packaging materials resulted in significant amount of infiltration rate. As for the field permeability test results, they were manifested similar tendency as indoor permeability test results and they satisfied the standard for standard of water permeability of domestic disparity facility (less than $1.0{\times}10-7cm$/sec). As compaction rate increased, unconfined compression strength increased as well while coefficient of water permeability decreased.

• 한국토양환경학회지
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• 제5권2호
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• pp.99-105
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• 2000

본 연구는 Pb으로 오염된 토양을 Biofilter에 의한 적용가능성을 판단하고 충전물질, bed수 그리고 미생물 접종에 따른 Pb의 이동억제효과의 변화를 Pilot plants의 실험을 하였으며 토양의 분해정도를 CODcr/TOC ratio로써 안정화 지표에 대한 변화를 검토하였다. 생물여과는 오염된 물질을 생물여과상를 통과시켜 충전물질표면에 부착되어있는 생물막의 각종미생물들에 의한 경계면을 통하여 물질의 상호교환 및 전환이 생기며 생물막내에 흡수된 물질을 생물학적으로 처리하는 방법의 일종이다. 본 연구는 오염된 토양에 lead nitrate를 첨가시켜 납을 1,000㎎/kg dry soil로 인공적으로 조제한후 충전물질로는 퇴비, 바이오세라믹 그리고 퇴비와 바이오세라믹을 중량비로 7:3으로 하였고, 1단, 2단, 3단으로 하고 이에따라 생물흡착제로 'Aspergillus niger'를 이용하며 납의 이동억제효과의 변화를 검토하였다.

• 한국기계가공학회지
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• 제21권3호
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• pp.29-35
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• 2022

When a vehicle is driven off a road surface, the deformations of the road surface and tire are combined. Consequently, the dynamic behavior of wheel movement becomes difficult to predict and control. Herein, we propose a tire test bed to capture the dynamic behavior of tires moving on sand and soil. Based on this study, it is discovered that the slip rate can be controlled, and the vertical force can be measured using a load cell. The test results show that this test bed can be useful for capturing the dynamic behavior of the tire and validating dynamic simulations. In fact, the tire test bed developed in this study can be used to verify the results of computer simulations. In addition, it can be used for basic experiments pertaining to the speed control of unmanned autonomous vehicles.

• Geomechanics and Engineering
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• 제9권2호
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• pp.219-241
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• 2015

In this paper, a series of repeated load tests were carried out on a 150 mm diameter plate simulative of vehicle passes, to demonstrate the benefits of soil-rubber shred mixture in decreasing the soil surface settlement of road embankment. The results show that the efficiency of rubber reinforcement is significantly a function of the rubber content, thickness of rubber-soil mixture and soil cap thickness over the mixture. Minimum surface settlement is provided by 2.5% of rubber in rubber-soil mixture, the thickness of mixture layer and soil cap of 0.5 times the loading surface diameter, giving values of 0.32-0.68 times those obtained in the unreinforced system for low and high values of amplitude of repeated load. In this installation, in contrast with unreinforced bed that shows unstable response, the rate of enhancement in settlement decreases significantly as the number of loading cycles increase and system behaves resiliently without undergoing plastic deformation. The findings encourage the use of rubber shreds obtained from non-reusable tires as a viable material in road works.

• 한국토양비료학회지
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• 제43권3호
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• pp.322-328
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• 2010

This study was initiated to investigate the physical and chemical properties of the clay mineral illite and its effect on the growth of cherry tomato (Hongjak) as affected by the forms and concentrations of illite using the bed soil in the glass house. The composition of illite was analyzed by SEM(scanning electron microscope). The cherry tomato was cultivated in the bed soil in the glass house at Chungbuk National University for 10 weeks of total duration. The application rates of illite used as particulate and powder forms were standard 1:20 (w/w), two times 1:10 (w/w), four times 1:5 (w/w) of standard application, respectively. The surface of illite used in the study appeared to be hexagonal sheet and it included K and the variety of other elements. The growth lengths of cherry tomato were 11-23% greater in the pots treated than in the untreated pots. Based on the analyses of the major cations, K, Ca, and Mg from the cherry tomato the amounts of K taken in the leaf and stem of the cherry tomato were 8-45% and 3-30% greater than untreated pots, respectively. The amount of Ca in the leaf and stem taken up by the cherry tomato were 6-39% and 11-40% greater than untreated pots, respectively. The amounts of Mg in the leaf and stem taken up by the cherry tomato were 17-62% and 19-54% greater than untreated pots, respectively. Based on the analysis for the amount of cations, such as K, Ca, and Mg taken up by cherry tomato in treated and untreated bed soil, it appears that the illite treatment enhanced the early growth of cherry tomato.

• 한국농림기상학회지
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• 제22권3호
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• pp.107-116
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• 2020

본 데이터 논문에서는 관측기반 농경지 토양수분 추정 기술 개발을 위해 서산과 태안에 2019년 5월에 구축한 테스트 베드에서 2019년 한해동안 얻어진 자료들을 공유하고자 한다. 본 데이터는 기상청에서 운영 중인 자동농업기상관측망 중에 하나인 서산 관측소 주변 밭과 인근 태안의 밭에 구축한 테스트 베드에서 얻어진 다양한 생태수문기상학적인 변수들(토양수분, 증발산, 강수, 복사, 기온, 습도, 식생지수 등)을 포함한다. 해당 데이터의 주목할 만한 사항은 (1) 토양수분관측을 Frequency Domain Reflectometry 및 Time Domain Reflectometry 센서를 이용한 지점관측 뿐만 아니라 COSMIC-ray 중성자 센서로 넓은 공간대표성을 지닌 면적관측을 동시에 수행하여 토양수분의 공간 스케일링 기술 개발 및 평가에 활용될 수 있다는 점, (2) Smart Surface Sensing System을 이용해 작물생육을 함께 감시함으로써 어떻게 토양수분과 작물생육이 상호작용하는지에 대한 이해를 증진시키는데 활용될 수 있다는 점, (3) 에디 공분산 시스템을 이용해 증발산을 함께 실측함으로써 지면 물수지 전반에 대한 평가가 가능하다는 점이다.