• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2003년도 봄 학술발표회 논문집
• /
• pp.741-746
• /
• 2003

The foundation of Noksan area is composed of consolidified sediments including clay mineral, quartz, plagioclase and calcite. The mineral compositions vary dependent on the depth. That is, at the depth of 0-15 meters quartz and plagioclase are more abundant than clay mineral, at the depth of 17-39 meters clay minerals and calcite are more than quartz and plagioclase, at the depth deeper than 40 meters, the amounts of quartz and plagioclase increase slightly and that of clay minerals decrease. Clay minerals of the clayey sediments include illite, smectite, kaolinite and chlorite. At the depth 17-39 meters smectite is abundant and kaolinite is little relatively The pH of suspension is various between 3-9 and decrease to 3-5 at the depth deeper than 40 meters. The result of soil test of clay sediments, water content shows that liquid limit, plastic limit, particle size, unconfined compressive strength varies depending on the depth. The variation of mineralogical, geochemical, engineering properties of soil with the depth are probably due the differing sediments of different sedimentary environment. That is, these variations are considered to be correlated with the sedimentary environment change resulting from the change from continental environment to ocean environment due to the transgression of the interglacial period after the regression the latest glacial period.

• 한국환경농학회지
• /
• 제39권4호
• /
• pp.327-333
• /
• 2020

BACKGROUND: Through Saemangeum development project, 283 ㎢ of new land is planned to be created and the reclaimed land of 89.7 ㎢ will be used as agricultural land. Therefore, monitoring of soil salinity is required to evaluate the suitability of the land for agricultural purposes. METHODS AND RESULTS: We investigated changes of soil physico-chemical properties, including electric conductivity (EC), of the Saemangeum reclaimed tidal land (1,195 ha) from 2008 to 2017 to obtain basic data for suitable soil management of the Saemangeum reclaimed tidal land. Soil samples were collected from the sites spaced 200 meters apart from each other. Soil analysis results showed that average soil EC was 14.5 dS m-1 in 2008, and decreased to 6.5 dS m-1 in 2014 and to 0.9 dS m-1 in 2017. Accordingly, the soil area below soil EC 4.7 dS m-1 (accepted as farmable soil salinity) increased; 25.0% in 2008, 54.3% in 2014, and 96.9% in 2017. The annual decrease in soil EC was described as y = -1.5756x + 14.6 (R2= 0.96), where y = soil EC and x = elapsed years since 2008. CONCLUSION: The soil salinity have decreased to a level for cultivation of most edible crops. However, since the soil chemical properties, such as soil organic matter were inadequate for the cultivation of crops, it was suggested that management of soil fertility would be important for efficient agricultural use of Saemangeum reclaimed land.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2001년도 추계학술대회 논문집
• /
• pp.558-561
• /
• 2001

SIP(Soil cement Injected Precast pile) that inserts a precast pile after injecting a cement paste into a boring has been applied rapidly through the change of construction circumstances. But there isnt any logical equation of a bearing capacity fitted to SIP yet. So Meyerhof equation has mainly been used to predict a bearing capacity in a design stage instead. But it has shortcomings such as lack of confidence because it has derived not from a theory but from an experience obtained from the result of SPT (Standard Penetration Test) and because a penetration depth tends to be deeper by an excessive design that depends on an end bearing capacity of a pile more than a skin frictional resistance. In this study, thereupon, a direct shear test in the laboratory was performed to both SM and SC soils in variable conditions to verify skin friction properties for the purpose of presenting some reasons capable of reducing penetration depths. Through the tests, soil to soil of SM in cohesion, rough panel to soil of SM in friction angle and soil to soil of SM in shear strength tended to be high. And a shear strength increased as its total unit weight increased in all cases.

• Geomechanics and Engineering
• /
• 제24권2호
• /
• pp.105-113
• /
• 2021

Deformations in soils induced by dynamic loads cause damage to the structures above the soil layers. It is important for geotechnical engineering practice that how the soil behaves due to repeated loads and the necessary precautions to be taken accordingly. Turkey is one of the most important seismic regions in Europe and earthquake studies to be conducted in this area are intended to reduce the damage as a result of taking the necessary measures. To determine the properties of soils under dynamic loads, stress-controlled dynamic triaxial and resonant column tests can be performed. In this study, these experiments were implemented in the laboratory on the clayey sand soil samples obtained from Bilecik Söğüt. To evaluate the effects of the confining pressure and rate of loading on the dynamic behavior of soils, samples were dynamically loaded by different rates at varying confining pressures. As a result, the changes in stress-strain properties of soils under dynamic loads were investigated. The alteration in behavior in terms of modulus reduction and damping ratios was obtained to vary a lot with the change of the lateral pressure on soil along with the frequency of the load.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2009년도 춘계 학술발표회
• /
• pp.966-972
• /
• 2009

Soil-aggregate system in pavement foundations exist in unsaturated conditions. However, change in water content on foundation layers due to joint and structural cracks during rainfall may cause problems like layer deformations or partial settlements. Therefore, a need exist to evaluate the infiltration and drainage capacity of soil-aggregate foundation system under both saturated and unsaturated conditions. To do that, a laboratory soil-water characteristic curve and permeability under unsaturated conditions are assessed to establish hydraulic properties of geomaterials and limited numerical analysis are performed respectively. As a result, it was found that suction profiles and drainage process was greatly influenced by the initial suction of soil-aggregate system at the time of infiltration, soil water characteristics curves, and hysteresis effects.

• 한국환경농학회지
• /
• 제17권2호
• /
• pp.170-173
• /
• 1998

신천하수종말처리장에서 발생한 슬러지를 처리별로 시용한 다음 토양의 이화학성(理化學性)과 중금속 함량변화를 조사하였다. 슬러지 시용량이 증가함에 따라 질소, 인산 및 무기염류의 함량이 증가하는 것으로 나타 났으며, 토양의 입단화, 공극률 및 투수성이 증가하였으며 경도는 감소하였다. 중금속 함량은 Cr, Zn의 경우 약간의 증가를 보였으며,함류량이 적어 시용량이 증가하여도 함량에 차이가 없으며, 하층으로 이동하거나 용탈하지 않는 것으로 나타났다. Sludge중 중금속 함량이 매우 낮음으로 sludge의 처리가 토양 중금속 함량에 별다른 영향을 주지 않았다.따라서 토양의 하부(下部)로 이동하는 현상도 나타나지 않았다.

• 유기물자원화
• /
• 제15권1호
• /
• pp.159-170
• /
• 2007

음식물류폐기물을 이용한 퇴비는 중금속과 같은 유해물질의 농도가 낮고, 유기물 농도가 높아 토양에 시비하여 토지개량제로의 역할이 기대된다. 본 연구에서는 포천시 일동면 소재의 나대지 (latitude $38^{\circ}0^{\prime}N$, longitude $127^{\circ}20^{\prime}E$)에 있는 음식물류폐기물 퇴비와 계분 퇴비를 각각 3, 6, $9kg/m^2$과 1, 2, $3kg/m^2$로 시용하여 열무의 성장특징과 생리적 특징, 토양의 이화학적 특성을 통해 음식물류폐기물 퇴비의 답 토양에 대한 이용 가능성을 평가하고자 하였다. 음식물류폐기물 퇴비를 사용한 포장에서의 열무는 초장의 경우 시비량이 증가할수록 성장량이 좋았으며, 잎수, 잎면적, 초부와 근부의 무게는 6 kg 처리구가 가장 성장량이 컸던 것으로 나타났다. 계분퇴비 시용구에서는 2 kg 처리구가 기타 처리구와 비교하여 상대적으로 성장량이 적었다. 생육 초기 음식물류폐기물 퇴비 9 kg의 성장량이 다른 처리구보다 적었으며, 이는 종자의 발아단계에서 음식물류폐기물 퇴비가 영향을 미친 것으로 추측된다. 용적밀도는 모든 시비처리구에서 감소하는 것으로 나타나 물리적 성질의 개선에 긍정적인 효과가 있을 것으로 판단되어 진다. 광합성능력도 염해, 오존, 질산성 질소와 같은 일반적인 외부 스트레스로 인한 감소와는 다른 경향을 보여 답 토양에 대한 이용 가능성이 있는 것으로 나타났다. 하지만 계분퇴비를 시비한 포장에서 electric conductivity(EC)의 농도는 점차 감소하는 경향을 보인 반면, 음식물류폐기물 퇴비 6, $9kg/m^2$ 시비구에서는 토양내 electric conductivity(EC)가 지속적으로 증가하는 경향이 나타났다. 따라서 음식물류폐기물을 원료로 한 퇴비를 시용하는 토양의 특성과 작물의 종류 및 기후 등에 따른 염류 집적에 대한 추가적인 연구가 이루어져 시비처방시에 고려되어져야 할 것으로 판단된다.

• Current Research on Agriculture and Life Sciences
• /
• 제29권
• /
• pp.29-35
• /
• 2011

The relationship between hydrologic processes and scale is one of the more complex issues in surface water hydrology. Disturbances that change vegetation and/or soil properties have been known to subsequently alter the landscape. The primary objective of this study was to estimate the grain size of soils with different properties from the hydraulic conductivity using pedotransfer functions. The double ring infiltrometer method was used to measure the vertical hydraulic conductivity of three soils under different soil planar surface treatments. Seven selected pedotransfer functions were used to estimate percentile diameters and the reduction in infiltration caused by compaction was misconstrued as caused by changes in percentile diameter. Results showed that compaction on the sandy loamy foot paths reduced the hydraulic conductivity by about 50%. The study showed that perceptual models of infiltration processes and appreciation of scale problems in modeling are far more sophisticated than normally presented in texts. Hydraulic measurement methods are still relevant and will provide significant information of grain size of the soils.

• 아시안잔디학회지
• /
• 제24권2호
• /
• pp.205-210
• /
• 2010

본 연구는 코스조성에 주로 사용되는 4종의 토양개량제의 혼합비율에 따른 모래상토의 물리화학적 특성변화를 조사한 결과이다. 토양개량제의 혼합비율에 따라 상토의 물리화학성을 조사한 결과 peat, humate, peatmoss 및 zeolite는 pH와 CEC에서 고도의 상관성(P<0.01)을 나타내어 토양개량제의 특성에 따라 상토의 토양화학성에 영향을 주었다. 상토의 토양물리성 결과를 통해 USGA 기준으로 평가할 때, 최적의 혼합비율은 토양개량제 peat, humate 및 peatmoss는 각각 5%, 3%, 7%이고, zeolite에서는 적합한 비율을 찾을 수 없었다. 각 토양개량제들의 혼합에 따른 토양물리성 변화에서 가장 중요한 요인은 비모세관공극으로 총공극과 수리전도도의 변화에 영향을 미쳤다. 토양개량제의 혼합비율에 따른 토양개선효과를 비교할 때, peat와 peatmoss는 토양 모세관공극 및 수리전도도에서, humate는 수리전도도에서, zeolite는 비모세관공극과 총공극에서 고도의 상관성을 나타내었다(P<0.05). 이들 결과를 통해 골프코스의 상토조성에 사용되는 토양개량제의 종류와 특성 및 혼합비율이 USGA 상토의 근권층 개량과 토양 이 화학성에 영향을 미치고 있음을 알 수 있었다.

• 한국농공학회논문집
• /
• 제65권3호
• /
• pp.15-28
• /
• 2023

The compaction properties of the soil change depending on the physical properties, and are also affected by crushing of the particles. Since the particle size distribution of soil affects the engineering properties of the soil, it is necessary to analyze the material properties to understand the compaction characteristics. In this study, the size of each sieve was classified into four in the particle size analysis as a material property, and the compaction characteristics were evaluated by multiple regression and maximum dry unit weight. As a result of maximum dry unit weight prediction, multiple regression analysis showed R² of 0.70 or more, and DNN analysis showed R² of 0.80 or more. The reliability of the prediction result analyzed by DNN was evaluated higher than that of multiple regression, and the analysis result of DNN-T showed improved prediction results by 1.87% than DNN. The prediction of maximum dry unit weight using particle size distribution seems to be applied to evaluate the compacting state by identifying the material characteristics of roads and embankments. In addition, the particle size distribution can be used as a parameter for predicting maximum dry unit weight, and it is expected to be of great help in terms of time and cost of applying it to the compaction state evaluation.