• 한국도로학회논문집
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• 제15권5호
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• pp.57-64
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• 2013

PURPOSES : It is to evaluate lightweight soil as a subgrade material based on mechanical tests and calculation of pavement performance. METHODS : In this research, various contents of cement and air foam are used to make lightweight soil using wasted dredged soil. Uniaxial compressive strength test is conducted to evaluate strength of 7 and 28 day cured specimens. Secant modulus was calculated based on the stress and strain relationship of uniaxial compressive strength test. Resilient modulus test was measured using by repeated triaxial compression test. The measured resilient modulus was used in layered elastic program to predict fatigue and rutting life at a given pavement structure. RESULTS : Uniaxial compressive strength increases as cement content increases but decrease as air foam content increases. Resilient modulus also increases as cement content increases and decrease as air foam content decrease. CONCLUSIONS : It is concluded that dredge clay soil can be used as subgrade layer material using by lightweight treated soil method.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1356-1358
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• 2003

In the paper, a method making use of the characteristics of Dyad Green Function (DGF) and Fluctuation-Dissipation Theorem to get the brightness temperature of layered medium is introduced. Based on the approach and the measured data of multi-channel radiometer and Least Square Method (LSM), the thickness of lunar soil can be retrieved. These methods are significant to study on materials on lunar surface.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2006년도 학술발표회 논문집
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• pp.628-636
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• 2006

This paper presents 3D infinite elements in Cartesian coordinates for the elastodynamic problem in multi-layered half-space. Five kinds of infinite elements are developed by using approximate expressions of multiple wave components for the wave function in exterior far-field soil region. They are horizontal, horizontal-corner, vertical, vertical-corner and vertical-horizontal-corner elements. The elements can be used for the multi-wave propagating problem. Numerical example analyses are presented for rigid disk, square footings and embedded footing on homogeneous and layered half-space. The numerical results obtained show the effectiveness of the proposed infinite elements.

• 자원환경지질
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• 제51권1호
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• pp.49-65
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• 2018

회곽묘는 조선시대 묘제의 한 형태로서 석회, 모래, 황토를 혼합한 삼물을 이용하여 곽을 축조한 무덤이다. 이 연구에서는 평택 궁리유적에서 출토된 조선시대 회곽묘를 대상으로 제작방식에 따라 층벽식과 통벽식으로 구분하여 재료학적 및 제작특성을 검토하였다. 분석시료는 석회혼합물과 토양으로 분류하였으며 회곽의 제작방식에 따른 삼물의 혼합특성도 해석하였다. 회곽은 내부의 환경을 제어하는데 직접적인 영향을 주는 벽체에서 상대적으로 석회함량이 높은 삼물을 사용하였으며, 이를 마감하는 층이나 바닥에는 상대적으로 석회함량이 적은 저품질의 삼물을 사용하였다. 전체적으로 층벽식보다 통벽식 회곽에서 석회함량이 높으며 물성도 우수한 것으로 나타났다. 삼물의 혼합에 사용한 토양과 유구 주변의 토양이 광물학 및 지구화학적으로 거의 유사한 것으로 나타났다. 따라서 삼물의 제조에 사용한 모래와 황토는 유구 주변에 분포하는 토양을 사용한 것으로 해석된다. 한편 궁리유적 인근에는 대규모의 석회암 산지가 다수 분포하고 있다. 또한 아산만을 통해 유입되는 바닷길이 유적 인근까지 연결되어 수운 등의 방법을 통해 인근 산지에서 석회재료가 공급되었을 가능성이 있다.

• Structural Engineering and Mechanics
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• 제33권1호
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• pp.47-66
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• 2009

Radiation damping due to wave propagation in unbounded domains may cause a significant reduction of structural vibrations when excited near resonance. Here a novel matrix-valued algebraic Pad$\acute{e}$-like stiffness formulation in the frequency-domain and a corresponding state equation in the time domain are elaborated for a soil-structure interaction problem with a layered soil excited in a transient manner by a flexible rotor during startup and shutdown. The contribution of radiation damping caused by a soil-layer upon a rigid bedrock is characterized by the corresponding amount of critical damping as it is used in structural dynamics.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1998년도 학술발표회 발표논문집
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• pp.521-526
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• 1998

This study was initiated to build runoff plots, install soil and water quality monitoring systems and collect background data from the plots and soils to assess runoff the nonpoint source pollution and soil physical change in mountainous soils. Eleven 3 $\times$ 15 m runoff plots and monitoring systems were installed at a field of National Alpine Agricultural Experiment Station to monitor soil physical change, and discharge of nonpoint source pollutant. Corn and potato were cultivated under different fertilizer, tillage and residue cover treatments. The soil has a single-layered cluster structure that has a relatively good hydrologic properties and can adsorb a large amount of nutrient. 11 runoff plots were treated and monitored with respect to physical property of the soil, runoff and sediment discharge.

• Interaction and multiscale mechanics
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• 제2권1호
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• pp.91-107
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• 2009

In order to accurately estimate the seismic behavior of buildings, it is important to consider both nonlinear characteristics of the buildings and the frequency dependency of the soil impedance. Therefore, transform methods of the soil impedance in the frequency domain to the impulse response in the time domain are needed because the nonlinear analysis can not be carried out in the frequency domain. The author has proposed practical transform methods. In this paper, seismic response analyses considering frequency dependent soil impedance in the time domain are shown. First, the formulation of the proposed transform methods is described. Then, the linear and nonlinear earthquake response analyses of a building on 2-layered soil were carried out using the transformed impulse responses. Through these analyses, the validity and efficiency of the methods were confirmed.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2005년도 학술발표회 논문집
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• pp.405-412
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• 2005

In this study, a numerical method for soil-pile-structure interaction problems in multi-layered half-plane is developed. The total soil-pile-structure interaction system is divided into two parts namely, nonlinear structure part and linear soil-pile interaction parts. In the structure field, the general finite element method is introduced to solve the dynamic equation of motion for the structure. In the soil-pile structure interaction part, physical model consisting of lumped parameter, which is frequency dependent coefficient and determined by rigorous analysis method is introduced. Using proposed analysis procedure, the nonlinear behavior of structure considering soil-structure interaction can be efficiently determined in time domain and the analysis cost is dramatically reduced.

• 농업과학연구
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• 제27권2호
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• pp.125-134
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• 2000

This observation was to investigate the influence of raw organic matter incorporated into soil at various rates on hydraulic conductivity and elution of solute throughout soil column. Generally the organic matter content in a practical agricultural field was approximately 3%. However, the application rate of organic matter in the field tends to rapidly increase in these days. Therefore, we raised the application rate of organic matter up to 10% in this investigation. From the experiment, we found that the hydraulic conductivities rapidly decreased with increasing rate of organic matter as well as rapid decrease in total volume of eluent during the same period. And electrical conductivities in the effluent significantly decreased after 2 pore volume, resulting in approaching to the criteria of saline soli. From this we could assume that the organic matter may influence the crop growth in the beginning. However excessive irrigation in the field may cause saturation of soil leading to reduction of soil. Therefore, there must be a management methods in application of organic matter with respect to soil water control.

• Geomechanics and Engineering
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• 제23권6호
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• pp.547-560
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• 2020

This paper studies the dynamic foundation-soil-foundation interaction for two square rigid foundations embedded in a viscoelastic soil layer. The vibrations come from only one rigid foundation placed in the soil layer and subjected to harmonic loads of translation, rocking, and torsion. The required dynamic response of rigid surface foundations constitutes the solution of the wave equations obtained by taking account of the conditions of interaction. The solution is formulated using the frequency domain Boundary Element Method (BEM) in conjunction with the Kausel-Peek Green's function for a layered stratum, with the aid of the Thin Layer Method (TLM), to study the dynamic interaction between adjacent foundations. This approach allows the establishment of a mathematical model that enables us to determine the dynamic displacements amplitude of adjacent foundations according to their different separations, the depth of the substratum, foundations masss, foundations embedded, and the frequencies of excitation. This paper attempts to introduce an approach based on a polynomial mathematical tool conducted from several results of numerical methods (BEM-TLM) so that practicing civil engineers can evaluation the dynamic foundations displacements more easy.