• 한국항해항만학회지
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• 제39권5호
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• pp.385-391
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• 2015

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.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.1073-1087
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• 1993

Many investigations have been carried out concerning tillage tool performance, including energy requirement . Since the performance of tillage could also be evaluated through the change of soil , then it is necessary to investigate the soil cutting process and the pattern of soil failure. This study was conducted using indoor soil bin, STILT (Soil Tillage Tool Interaction) system. The result shows that the soil bin experiments could provide the clear understandings about phenomena of soil failure. The movement of sil , the successive failures was clearly visualized. The relations between the horizontal and vertical forces to the linear motion blade, the shear force on the shear plane which devides soil layer into several segments were indicated by the fluctuation/vibration of the recorded resistance and forces. The results show that the horizontal force(Fx) and vertical force (Fz) develope their frequencies as the change of velocity of blade (10, 20, 40 mm/sec) for each cutting angle (35, 45, 60 degrees). Resultant force of Fx and Fz are much influenced by the cutting angle.

• Structural Engineering and Mechanics
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• 제5권1호
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• pp.1-19
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• 1997

A numerical procedure for dynamic analysis of structures including lateral-torsional coupling, axial force effect and soil-structure interaction is presented in this study. A simple soil-structure system model has been designed for microcomputer applications capable of reflecting both kinematic and inertial soil-foundation interaction as well as the effect of this interaction on the superstructure response. A parametric study focusing on inertial soil-structure interaction is carried out through a simplified nine-degree of freedom building model with different foundation conditions. The inertial soil-structure interaction and axial force effects on a 20-storey building excited by an Australian earthquake is analysed through its top floor displacement time history and envelope values of structural maximum displacement and shear force.

• Journal of Biosystems Engineering
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• 제29권3호
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• pp.251-260
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• 2004

As a basic experiment for robot hand for transplanting plug seedling, the experimental robot hand system which moves up and downward vertically, and allows hand blade to open and close was made. The system was constructed with the robot hand mechanism, the tray, the plug seedling, and the measuring equipments. The penetrating force and holding efficiency were analyzed according to the soil moisture and the variation of hand blade angle. The highest holding efficiency could be obtained at the penetrating angle of approximately from 0 to 0.36 degree and at the moisture content of soil from 71% to 75%. The external force acted on the robot hand should maximum force when the robot hand was penetrated to soil, minimum of approximately 30.4 N when the penetrating angle was 0$^{\circ}$ and moisture content was 66-70%. It was increased with increasing or decreasing the Penetrating angle from 0 degree and also with increasing or decreasing the moisture content of soil from 66-70%. For optimal design of the robot hand and manipulator, the external force acted on robot hand had to be based on the returning force of soil, when the robot hand was penetrated to the soil. In consideration of safety ratio, the appropriate external force seemed to be 39-49 N.

• Journal of Biosystems Engineering
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• 제2권1호
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• pp.25-32
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• 1977

This experiment was conducted in order to find out the drawing performance of a two-wheel tractor under different levels of the soil moisture and hardness, so as to obtain some basic data for improving their drawing performance. With fairly homogeneous soil, 5 levels of soil moisture contents (8, 13, 17, 20 and 23%) and 3 levels of soil hardness (0 , 2 and 4kg/$cm^2$) were selected for this experiment.The summerized results are as follows ;1. The draft force, on the hard soil (hardness ; 4kg/$cm^2$), had a distinct tendency to decrease with the increasing soil moisture. On the medium soil (hardness ; 2 kg/$cm^2$), and the soft soil (hardness ; 0kg$cm^2$), the draft force showed the highest when the moisture contents were within the range of 16-19%.But the maximum draft force, on the soft soil, was higher than that on the medium soil by 10 %. 2. The driving axle torque increased with increasing soil by 10 %. 3.The values of horizontal distance between the soil reaction point and axle shaft were within the range of 0~10cm , and it had the tendency to increase with the increasing soil moisture. Also, it s value was the largest on the hard soil and the smallest on the soft soil. 4.The tractive efficiency decreased with the increasing soil moisture. On the hard soil, the average value of tractive efficiency was higher than that on the medium soil by 19.0% and that on the soft soil was lower than that on the medium soil. 5.The traction ratio were within the range of 30 ~45%, and their changing tendency with respect to the soil moisture was similar to that in the case of the draft force. 6. The travel resistance ratio tended to increased with increasing soil moisture, and the highest value was found on the soft soil, and the lowest on the hard soil.

• 한국농공학회지
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• 제35권4호
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• pp.47-54
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• 1993

A series of laboratory tests was performed with soil-columns which were compacted with sands and different amount of silt collected from the mid-stream of Gumgang, Korea. A known degree of concentration of PCP(Pentachlorophenol) was poured into the soil-columns and concentration of PCP was monitored and analyzed with time and depth. The results of the study are summarized as follows : 1. PCP was transported into soil along with the movement of moisture under gravitational force. The amount of PCP transported through soil or absorbed by soil varied with soil types. 2. The great amount of PCP was remained at 4~8cm section for the specimen No.2 and at 0~4cm section for the specimen Nos. 3 and 4. Based upon this result it is said that the amount of silt between 30 and 40% may be a threshold value for PCP transported through soil. 3. The amount of PCP remained in the specimen Nos. 2, 3 and 4 is greater than that in the specimen No.1 due to high specific surface of silt and high attraction force between PCP and silt particles in the specimen Nos. 2, 3 and 4. 4. It is said that groundwater under highly permeable soil layer such as specimen No.1 is easily polluted by PCP. That is because the PCP is basically migrated with water under the gravitational force.

• 한국초전도ㆍ저온공학회논문지
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• 제23권3호
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• pp.26-31
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• 2021

Advanced classification of Cs contaminated soil by using a magnetic force-assisted selection pipe was investigated. A selection pipe is a device that sort particles depending on their particle size, based on the relationship between buoyancy, drag, and gravity force acting on the particles. Radioactive cesium is concentrated in small-particle size soil components with a large specific surface area. Hence, the volume of the Cs contaminated soil can be reduced by recycling the large-particle size soil components with low radioactive concentration. One of the problems of the selection pipe was that the radioactive concentration of the stayed soil in the selection pipe exceeds 8000 Bq/kg, which is the standard value of recycling of Cs contaminated soil, due to low classification accuracy. In this study, magnetic fields were applied to the lab-scale selection pipe from upper side to improve the classification accuracy and to reduce the radioactive concentration of the stayed soil.

• Earthquakes and Structures
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• 제24권3호
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• pp.155-163
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• 2023

The purpose of this paper is to investigate the coupled effect of SSI and pounding on dynamic responses of unequal height adjacent buildings with insufficiently separation distance subjected to seismic loading. Numerical investigations were conducted to evaluate effect of the pounding coupling SSI on a Reinforced Concrete Frame Structure system constructed on different soil fields. Adjacent buildings with unequal height, including a 9-storey and a 3-storey reinforced concrete structure, were considered in numerical studies. Pounding force response, time-history and root-mean-square (RMS) of displacement and acceleration with different types of soil and separations were presented. The numerical results indicate that insufficient separation could lead to collisions and generate severe pounding force which could result in acceleration and displacement amplifications. SSI has significant influence of the seismic response of the structures, and higher pounding force were induced by floors with stiffer soil. SSI is reasonable neglected for a structure with a dense soil foundation, whereas SSI should be taken into consideration for dynamic analysis, especially for soft soil base.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.1406-1416
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• 2008

Soil nailing is used as a method of slope stabilization and excavation support. The design method of soil nail are based on experience or assumption of interaction between soil and reinforcement. Most design methods simply considers the tension of reinforcement for analysis of slope stabilization. Soil nails interact with soils under combined loading of shear and tension. Jewell & Pedley(1990) suggested a design equation of shear force with bending stiffness and discussed that the magnitude of the maximum shear force is small in comparison with the maximum axal force. However, they have used a very conservative limiting bearing stress on nails. This paper discusses that the shear strength of soil nails should not be disregarded with proper bearing stresses on nails. The modified FHWA design method was proposed by considering shear forces on nails with bending stiffness.

• 대한기계학회논문집A
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• 제33권11호
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• pp.1332-1340
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• 2009

The front end wheel loader is widely used for the loading of materials in mining and construction fields. It has repetitive digging, loading and dumping procedures. The bucket is subjected to large resistance force from the soil during scooping. We considered the soil reaction force characteristics from scooping procedure, the protection by overload and automatic scooping mode algorithm. The main topic of this paper is the analysis of the soil reaction force characteristics. The analysis of soil mechanics is carried out and the developed soil model is verified by experimental results from the simplified experimental equipment. A simplified model of the soil shape and bucket trajectory is used to determine the scooping direction based on an estimation of the resistance force applied on the bucket during the scooping motion. In the future, this model will be used for the generation of an appropriate path for the wheel loader automation.