Vertical and torsional soil reactions for radially inhomogeneous soil layer

El Naggar, M. Hesham Techno-Press 2000 Structural Engineering and Mechanics, An Int'l Jou Vol.10 No.4

The response of an embedded body to dynamic loads is greatly influenced by the reactions of the soil to the motion of the body. The properties of the soil surrounding embedded bodies (e.g., piles) may be different than those of the far-field for a variety of reasons. It may be weakened or strengthened according to the method of installation of piles, or altered due to applying one of the soil strengthening technique (e.g., electrokinetic treatment of soil, El Naggar et al. 1998). In all these cases, the shear strength of the soils and its shear modulus vary gradually in the radial direction, resulting in a radially inhomogeneous soil layer. This paper describes an analysis to compute vertical and torsional dynamic soil reactions of a radially inhomogeneous soil layer with a circular hole. These soil reactions could then be used to model the soil resistance in the analysis of the pile vibration under dynamic loads. The soil layer is considered to have a piecewise, radial variation for the complex shear modulus. The model is developed for soil layers improved using the electrokinetic technique but can be used for other situations where the soil properties vary gradually in the radial direction (strengthened or weakened). The soil reactions (impedance functions) are evaluated over a wide range of parameters and compared with those obtained from other solutions. A parametric study was performed to examine the effect of different soil improvement parameters on vertical and torsional impedance functions of the soil. The effect of the increase in the shear modulus and the width of the improved zone is investigated.

Dependence of Nutrient Supplying Capacity on Chemical reactions of Paddy Soil

Yoo-Hak Kim(김유학),Myung-Sook Kim(김명숙),Seong-Soo Kang(강성수),Hee-Joong Jun(전희중) 한국토양비료학회 2009 한국토양비료학회지 Vol.42 No.S2

논토양에서 지속가능한 농업생산 및 환경보호를 위한 양분관리는 토양의 화학반응들에 따른 지표들을 활용하는 것이다. 이 연구는 동일비료 영년시험 결과와 2000년부터 2002년까지 수행된 논토양 유형별 질소수준 시험 결과 등을 토대로 하여, 논토양의 화학작용 및 이와 관련된 양분공급력 지표들을 조사하였다. 논토양의 화학작용은 영양성분의 흡탈착 및 유기물질의 분해를 통한 수소, 전자, 이산화탄소의 생성작용과 이들 물질에 의한 화학작용 등으로 구성되었다. 이러한 토양의 화학작용을 고려한 양분공급력 지표들은 다음과 같았다. 질소의 공급력 지표는 토양유기물 또는 토양단백질이었으며, 인산의 공급력 지표는 유효인산함량이었고, 칼륨의 공급력 지표는 양이온교환용량과 치환성 양이온함량이었다. 한국에서는 논토양의 시비 추천식은 이러한 양분공급력 지표들을 사용하여 설정한 것으로 나타나 환경을 보전하면서 농업생산을 지속적으로 유지할 수 있는 것으로 판단된다. The practice of supplying nutrients for paddy soil with sustaining human health and ecological soundness is to utilize indicators considering soil chemical reactions. The long-term basis experiment of fertilizer and amendment of paddy soil and an experiment of yield response of soil types on nitrogen level from 2000 till 2002were used to search indicators of nutrient supplying capacity related to soil chemical reactions. Chemical reactions of paddy soil was composed of dissociating and/or adsorbing nutrients and of decomposing soil organic matter (SOM) into H?, e?, CO₂ in paddy soil. The indicators of nutrient supplying capacity, which were establishedby considering soil chemical reactions, were SOM or soil protein for nitrogen and available phosphate for phosphorus and cation exchangeable capacity (CEC) and exchangeable potassium for potassium. Korea has used fertilizer recommendation equations established with the indicators of nutrient supplying capacity for paddy soil.

Dependence of Nutrient Supplying Capacity on Chemical reactions of Paddy Soil

김이현,김명숙,강성수,조현준 한국토양비료학회 2009 한국토양비료학회지 Vol.42 No.4

The practice of supplying nutrients for paddy soil with sustaining human health and ecological soundness is to utilize indicators considering soil chemical reactions. The long-term basis experiment of fertilizer and amendment of paddy soil and an experiment of yield response of soil types on nitrogen level from 2000 till 2002 were used to search indicators of nutrient supplying capacity related to soil chemical reactions. Chemical reactions of paddy soil was composed of dissociating and/or adsorbing nutrients and of decomposing soil organic matter (SOM) into H+, e, CO2 in paddy soil. The indicators of nutrient supplying capacity, which were established by considering soil chemical reactions, were SOM or soil protein for nitrogen and available phosphate for phosphorus and cation exchangeable capacity (CEC) and exchangeable potassium for potassium. Korea has used fertilizer recommendation equations established with the indicators of nutrient supplying capacity for paddy soil which are.

Dependence of Nutrient Supplying Capacity on Chemical reactions of Paddy Soil

김유학,김명숙,강성수,전희중,Kim, Yoo-Hak,Kim, Myung-Sook,Kang, Seong-Soo,Jun, Hee-Joong 한국토양비료학회 2009 한국토양비료학회지 Vol.42 No.S2

논토양에서 지속가능한 농업생산 및 환경보호를 위한 양분관리는 토양의 화학반응들에 따른 지표들을 활용하는 것이다. 이 연구는 동일비료 영년시험 결과와 2000년부터 2002년까지 수행된 논토양 유형별 질소수준 시험 결과 등을 토대로 하여, 논토양의 화학작용 및 이와 관련된 양분공급력 지표들을 조사하였다. 논토양의 화학작용은 영양성분의 흡탈착 및 유기물질의 분해를 통한 수소, 전자, 이산화탄소의 생성작용과 이들 물질에 의한 화학작용 등으로 구성되었다. 이러한 토양의 화학작용을 고려한 양분공급력 지표들은 다음과 같았다. 질소의 공급력 지표는 토양유기물 또는 토양단백질이었으며, 인산의 공급력 지표는 유효인산함량이었고, 칼륨의 공급력 지표는 양이온교환용량과 치환성 양이온함량이었다. 한국에서는 논토양의 시비 추천식은 이러한 양분공급력 지표들을 사용하여 설정한 것으로 나타나 환경을 보전하면서 농업생산을 지속적으로 유지할 수 있는 것으로 판단된다. The practice of supplying nutrients for paddy soil with sustaining human health and ecological soundness is to utilize indicators considering soil chemical reactions. The long-term basis experiment of fertilizer and amendment of paddy soil and an experiment of yield response of soil types on nitrogen level from 2000 till 2002were used to search indicators of nutrient supplying capacity related to soil chemical reactions. Chemical reactions of paddy soil was composed of dissociating and/or adsorbing nutrients and of decomposing soil organic matter (SOM) into $H^+$, $e^-$, $CO_2$ in paddy soil. The indicators of nutrient supplying capacity, which were established by considering soil chemical reactions, were SOM or soil protein for nitrogen and available phosphate for phosphorus and cation exchangeable capacity (CEC) and exchangeable potassium for potassium. Korea has used fertilizer recommendation equations established with the indicators of nutrient supplying capacity for paddy soil.

경계반력법을 이용한 지진격리 원전구조물의 비선형 지반-구조물 상호작용 해석

이은행,김재민,이상훈 한국지진공학회 2015 한국지진공학회논문집 Vol.19 No.1

This paper presents a detailed procedure for a nonlinear soil-structure interaction of a seismically isolated NPP(Nuclear Power Plant) structure using the boundary reaction method (BRM). The BRM offers a two-step method as follows: (1) the calculation of boundary reaction forces in the frequency domain on an interface of linear and nonlinear regions, (2) solving the wave radiation problem subjected to the boundary reaction forces in the time domain . For the purpose of calculating the boundary reaction forces at the base of the isolator, the KIESSI-3D program is employed in this study to solve soil-foundation interaction problem subjected to vertically incident seismic waves. Wave radiation analysis is also employed, in which the nonlinear structure and the linear soil region are modeled by finite elements and energy absorbing elements on the outer model boundary using a general purpose nonlinear FE program. In this study, the MIDAS/Civil program is employed for modeling the wave radiation problem. In order to absorb the outgoing elastic waves to the unbounded soil region, spring and viscous-damper elements are used at the outer FE boundary. The BRM technique utilizing KIESSI-3D and MIDAS/Civil programs is verified using a linear soil-structure analysis problem. Finally the method is applied to nonlinear seismic analysis of a base-isolated NPP structure. The results show that BRM can effectively be applied to nonlinear soil-structure interaction problems.

Phosphorus-cadmium interactions in paddy soils

Seshadri, B.,Bolan, N.S.,Wijesekara, H.,Kunhikrishnan, A.,Thangarajan, R.,Qi, F.,Matheyarasu, R.,Rocco, C.,Mbene, K.,Naidu, R. Elsevier Scientific Pub. Co 2016 Geoderma Vol.270 No.-

<P>Regular application of phosphate (P) fertilisers has been identified as the main source of heavy metal(loid) contamination including cadmium (Cd) in agricultural soils. Some of these P fertilisers that act as a source of Cd contamination of soils have also been found to act as a sink for the immobilisation of this metal(loid). In paddy soils, redox reactions play an important role in the (im)mobilisation of nutrients and heavy metal(loid)s, as a result of flooding of the rice plains. Although a number of studies have examined the potential value of P compounds in the immobilisation of metals in contaminated soils, there has been no comprehensive review on the mechanisms involved in the P-induced (im)mobilisation of Cd in paddy soils. There are a number of factors that influences P induced Cd (im)mobilisation in paddy soils that include pH, redox reactions, liming effect, rhizosphere acidification and root iron plaques. Following a brief overview of the reactions of Cd and common P compounds that are used as fertiliser in soils, the review focuses on the above mentioned mechanisms for the (im)mobilisation of Cd by P compounds in paddy soils. The role of iron plaques on Cd status in soil and rice plants is also discussed followed by a summary and future research needs. (C) 2015 Elsevier B.V. All rights reserved.</P>

판별분석을 이용한 토지이용별 토양 특성 변화 연구

고경석(Kyung-Seok Ko),김재곤(Jae Gon Kim),이진수(Jin-Soo Lee),김탁현(Tack Hyun Kim),이규호(Gyoo Ho Lee)조춘희(Choon Hee Cho),오인숙(In Suk Oh),정영욱(Young Wook Cheong) 대한자원환경지질학회 2005 자원환경지질 Vol.38 No.3

The physical and chemical characteristics of soils in a small watershed were investigated and the effect of geology and land use on soil quality were examined by using multivariate statistical methods, principal components analysis and discriminant analysis. The soil developed from andesite had finer texture and higher contents of water extractable inorganic components, clay, and mafic minerals than the soil developed from granite. It is considered that the accumulation of salts in the farmland soils indicated by electrical conductivity, contents of cations and anions and pH was caused by fertilizer input during cultivation. The low contents of organic matter in the farmland soils was due to the enhanced oxidation of organic matter by tillage and by the harvest of crops. The contents of inorganic components are increased as following order: upland 〉 orchard 〉 paddy field 〉 forest. The high contents of water soluble SO 4 2− of paddy soils is due to the oxidation of sulfides mineral formed during the flooding period during the air-dry and extraction. The results of principal components analysis show the difference of soil quality was controlled by geology and land use. PC1 indicate the input of fertilizer, mineral weathering and ion exchange reaction by application of nitrogenous fertilizers. The results of two discriminant analyses using water extractable inorganic components and their ratios by land use were also clearly classified by discriminant function 1 and 2. In discriminant analysis by components, discriminant function 1 indicated the effect of fertilizer application and increased as following order: upland 〉 orchard 〉 paddy field 〉 forest soil. The investigated and predicted data for land use from discriminant analysis showed similar results. The discriminant analysis can be used as a useful method certifying the change of land use. 본 연구에서는 회동저수지 상류 수영강 유역에 발달된 토양을 대상으로 지질 및 토지이용별로 토양의 물리화학적 특성을 조사하고 그 영향을 다변량 통계분석법인 주성분 및 판별분석을 이용하여 고찰하였다. 연구지역내 토양의 토성은 안산암에서 발달한 토양이 화강암의 것보다 세립질이며 용출 무기성분, 점토 및 유색광물의 함량도 높았다. 경작지 토양 내 염류 집적(EC, 양이온, 음이온)과 pH 증가는 대부분 경작과정에 투입된 비료의 영향에 의한 것이며 임야 토양에 비해 상대적으로 낮은 유기물 농도는 경운에 의한 유기물의 산화 촉진 및 작물 수확에 기인하는 것이다. 토지이용별 무기성분의 함량은 밭〉과수원〉논〉임야 토양 순으로 나타났으며, 논 토양의 높은 SO 4 2 − 함량은 담수 상태 환원조건하 침전된 황화광물형태가 산화조건의 용출 실험에 의해 용해되어 증가되는 것에 기인한다. 주성분 분석 결과는 토지 이용이나 지질에 따른 토양 특성을 잘 나타내었으며, 주성분 1은 시비, 광물 풍화작용 및 질소질 비료에 의한 이온교환 반응의 영향을 나타내었다. 토양 용출 성분과 성분비를 이용한 두 종류의 판별분석결과는 모두 토지이 용별로 판별함수 1과 2에 의해 뚜렷하게 구분되며, 토양 성분을 이용한 판별분석에서 판별함수 1은 경작에 의한 비료의 영향을 나타내며 밭, 과수원, 논, 임야 토양 순서로 증가하였다. 판별분석에 의한 토지이용 특성의 조사 및 예측 자료는 비교적 잘 일치하였으며 토지 이용의 변화를 확인할 수 있는 방법으로도 사용될 수 있었다.

Analysis of Offshore Wind Tower against Impulsive Breaking Wave Force by P-Y Curve

Nam-Hyeong Kim,Myung-Jin Koh 한국항해항만학회 2015 한국항해항만학회지 Vol.39 No.5

In offshore, various external forces such as wind force, tidal current and impulsive breaking wave force act on offshore wind tower. Among these forces, impulsive breaking wave force is especially more powerful than other forces. Therefore, various studies on impulsive breaking wave forces have been carried out, but the soil reaction are incomplete. In this study, the p-y curve is used to calculate the soil reaction acting on the offshore wind tower when an impulsive breaking wave force occurs by typhoon. The calculation of offshore wind tower against impulsive breaking wave force is applied for the multi-layered soil. The results obtained in this study show that although the same wave height is applied, the soil reaction generated by impulsive breaking wave force is greater than the soil reaction generated by wave force.

원전구조물의 비선형 시간영역 SSI 해석을 위한 경계반력법에 의한 유효지진하중과 PML의 적용

이혁주,임재성,문일환,김재민 한국지진공학회 2023 한국지진공학회논문집 Vol.27 No.1

Considering the non-linear behavior of structure and soil when evaluating a nuclear power plant's seismic safety under a beyond-design basis earthquake is essential. In order to obtain the nonlinear response of a nuclear power plant structure, a time-domain SSI analysis method that considers the nonlinearity of soil and structure and the nonlinear Soil-Structure Interaction (SSI) effect is necessary. The Boundary Reaction Method (BRM) is a time-domain SSI analysis method. The BRM can be applied effectively with a Perfectly Matched Layer (PML), which is an effective energy absorbing boundary condition. The BRM has a characteristic that the magnitude of the response in far-field soil increases as the boundary interface of the effective seismic load moves outward. In addition, the PML has poor absorption performance of low-frequency waves. For this reason, the accuracy of the low-frequency response may be degraded when analyzing the combination of the BRM and the PML. In this study, the accuracy of the analysis response was improved by adjusting the PML input parameters to improve this problem. The accuracy of the response was evaluated by using the analysis response using KIESSI-3D, a frequency domain SSI analysis program, as a reference solution. As a result of the analysis applying the optimal PML parameter, the average error rate of the acceleration response spectrum for 9 degrees of freedom of the structure was 3.40%, which was highly similar to the reference result. In addition, time-domain nonlinear SSI analysis was performed with the soil's nonlinearity to show this study's applicability. As a result of nonlinear SSI analysis, plastic deformation was concentrated in the soil around the foundation. The analysis results found that the analysis method combining BRM and PML can be effectively applied to the seismic response analysis of nuclear power plant structures.

오염준설토의 중금속 안정화를 위한 Hydrothermal Reaction의 최적 조건 도출

이선주,안현규,조우리,김수희,이재영,Lee Sun-Ju,An Hyeon-Kyu,Cho Woori,Kim Su-Hee,Lee Jai-Young 한국지하수토양환경학회 2024 지하수토양환경 Vol.29 No.1

Hydrothermal Reaction (HTR) was applied for the stabilization of contaminated soil with heavy metals, and then the test determined the optimal conditions for HTR. After HTR, the concentration of heavy metals in the contaminated soil increased. However, it was observed that the leachability potential significantly decreased as determined by TCLP and SPLP tests. This decrease was attributed to a decline in fractions 1-2 and an increase in fractions 3-4 as revealed by sequential extraction procedure. Due to the mineralogical characteristics of the dredged soil, distinct changes were not evident in the five-stage fraction. Therefore, it is deemed necessary to understand the chemical and mineralogical characteristics of the target soil for HTR application in order to selectively address contaminants. Comparison among operating conditions determined the optimal condition to be at 240℃ for one hour.