• Structural Engineering and Mechanics
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• v.15 no.3
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• pp.315-329
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• 2003

As shear occurs along a soil-structure interface, a localized zone with a thickness of several grain diameters will develop in soil along the interface, forming an interfacial layer. In this paper, the behaviour of a soil-structure interface is studied numerically by modelling the plane shear of a granular layer bounded by rigid plates. The mechanical behaviour of the granular material is described with a micro-polar hypoplastic continuum model. Numerical results are presented to show the development of shear localization along the interface for shearing under conditions of constant normal pressure and constant volume, respectively. Evolution of the resistance on the surface of the bounding plate is considered with respect to the influences of grain rotation.

• Geomechanics and Engineering
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• v.3 no.1
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• pp.29-43
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• 2011

In this paper a semi-analytical approach is proposed to study the lateral behavior of a piled footing under horizontal loading. As accurate computation of stresses is usually needed at the interface separating the footing (pile) and the soil, this important location should be appropriately modeled as zero-thickness joint element. The piled footing is embedded in elastic soil with either homogeneous modulus or modulus proportional to depth (Gibson's soil). As the pile is the principal element in the piled footing system, a limited parametric study is carried out in order to investigate the influence of footing dimensions and the interface conditions on the lateral behavior of the pile. Hence, the pile behavior is examined through its main governing parameters, namely, the lateral displacement profiles, the bending moments, the shear forces and the soil reactions. The numerical results are presented for Poisson's ratio of 0.2 to represent a large variety of sands and Poisson's ratio of 0.5 to represent undrained clays.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1997.10a
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• pp.117-125
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• 1997

ABSTRACT This paper presents results of parametric studies of the seismic responses of a reactor containment structure on layered base soil. Among the numerous parameters, this study concentrates on the effects of embedment of structure to the base soil, thickness of the soil layers, stiffness of the base soil, and the definition point of the input motion. For the analysis, a substructure method using frequency independent impedances is adopted. The method is based on the mode superposition method in time domain using the composite modal damping values of the SSI system computed from the ratio of dissipated energy to the strain energy for each mode. From the study results, the sensitives of each parameter on the earthquake responses have been suggested for the practical application of the substructure method of SSI analysis.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.415-422
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• 1999

The general concept of reinforced roadbed in the high-speed railway is to cope with the soft ground for the bearing capacity and settlement of foundation soil. The cyclic plate load tests were performed to determine the behavior of reinforced ground with multiple layers of geogrid underlying by soft soil. Five series of test were conducted with varying the soil profile conditions including the ground level, type of soil, and the thickness of each soil layer. Based on these plate load tests, laboratory model tests under cyclic loading were conducted to know the effect of geogrid reinforcement in particular for the high-speed rail roadbed. The permanent settlement and the behavior of earth pressure in reinforced roadbed subjected to a combination of static and dynamic loading are presented.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.40-48
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• 2010

Saemangeum reclaimed area is needed to construct much green zone to make high-quality multi-functional land such as tide embankment, lake dike, industrial complex, environmental spaces, etc. However, growth of plants is somewhat difficult because a salinity of Saemangeum soil is very high and a soil fertility, water content of soil are low. Therefore, it is essential to initial desalination of soil and continuous management for planting base. It is recommended that a group of grassland to raise the efficiency of covering should be made in the first stage and a forest by improvement of vegetation should be made in the mid and long term stage. It is recommended that the construction of vegetation base should be made with a regular thickness of soil of good quality in multi-functional area such as a shrub and wood. In case of construction of a windbreak forest, it is necessary to make a wood base of suitable depth using soil brought from another place or filling of soil. Also, it is necessary to keep a maintenance of woods in early stage. Saemangeum reclaimed land will be brand-named worldwide tourist attractions due to construction of much green zone having high quality multi-functional facilities.

• Journal of the Korean Geosynthetics Society
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• v.4 no.3
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• pp.45-52
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• 2005

Most marine structures are constructed on very soft soil, soil improvements are needed for the area of road, buildings. In this paper, some considerations of several case studies on soil placement method after geotextile placement, known as surface treatment, are done. Considerations of strength applicability on the advanced construction method of sand and soil placement are proposed in this paper. Typical tensile strength of geotextile used in the surface soil stabilization method is 15t/m, and thickness of sand and soil placement between 1.6m and 3.1m. Undrained shear strength of soft clay layer ranges $0.2{\sim}1.2t/m^2$. In order to minimize the difficulties which include soil disturbance, soft soil gush and overturn of vertical drain installation rig more studies are needed.

• Journal of the Korean Geotechnical Society
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• v.25 no.4
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• pp.91-103
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• 2009

Slope failure depends upon the climatic features related to related rainfall, structural geology and geomorphological features as well as the variation of the mechanical behaviors of soil constituting a slope. In this paper, among many variables, effects of soil layer thickness on the slope failure process, and variations of matric suction and volumetric water content were observed. When the soil layer is relatively thick, the descending wetting front decreases matric suction and the observed matric suction reaches to "0" value. When the wetting front reaches to the impermeable boundary, the bottom surface of steel soil box, ascending wetting front was observed. This observation can be postulated to be the effects of various sizes of pores. When macro size pores exist, the capillary effects can be reduced and infilling of pore will be limited. The partially filled pores would be filled with water during the ascending of the wetting front, which bounces from the impermeable boundary. This assumption has been assured from the observation of variation of the volumetric water contents at different depth. When the soil layer is thick (thickness = 20 cm), for granular material, erosion is a cause triggering the slope failure. It has been found that the initiation of erosion occurs when the top soil is fully saturated. Meanwhile, when the soil layer is shallow (thickness = 10 cm), slope slides as en mass. The slope failure for this condition occurs when the wetting front reaches to the interface between the soil layer and steel soil box. As the wetting front approaches to the bottom of soil layer, reduction of shear resistance along the boundary and increase of the unit weight due to the infiltration occur and these produce complex effects on the slope failure processes.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.6
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• pp.117-122
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• 2006

The objective of this study is to analyze the greenroof runoff quantity and delay. The experimental districts, have different soil thickness and vegetation, had installed. A measurement was conducted in Seoul University to investigate the runoff quantity and delay of the greenroof. The measurement point of runoff quality data were 8, located next to each experimental district. Also, the precipitation was measured by rain gauges(# RG2). The experimental investigation lasted from 21th July to 4th December, a total of 137 days. The results showed that the greenroof can contribute runoff retention and delay by soil, but the intensity of actual rain event affected the runoff reduction and delay. Overall, when was the rainy season, percent rainfall retention ranged 17.5% and runoff flow was delayed for 1-3 hours. But on the other hand, when was the typical rain event, percent rainfall retention ranged over 90% and runoff flow was delayed for 1-11 hours. In the result, the greenroof had the greatest runoff retention and delay, while for the typical rain event.

• Magazine of the Korean Society of Agricultural Engineers
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• v.16 no.2
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• pp.3395-3409
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• 1974

The purpose of this study is to test and compare the efficiency of heating-system for materials and construction of the wall, ceiling and window in soil brick house, cement house and boulder house respectively, in order to construct ideal farm houses in rural area. The results obtained were as follows: 1. In heat conservation due to construction of walls the thermal efficiency of cement brick house was equivalent to 66.3% of that of soil brick house, and boulder house 60.3% 2. In the case of ceiling, the thermal efficiency of paper ceiling was amounted to 84.2% of that of the composite ceiling (thickness 6mm veneer+thickness. l0m chaffs), and the common ceiling putting on soil above the ceiling, 76% of the composite while the efficiency of the ceiling putting on chaffs above them was 15.8% higher than that of the paper. 3. In the case of improving the window, the double type was 12% higher than. the efficiency of single type. 4. The warming velocity of conventional house was slower but the velocity of radiation was quicker than that of experimental one. It was thought to be due to unscietific constructions of the room bottom, fire inlet and chimney, 5. The temperature gradient line was not dependad upon the amount of throwing into fuel in the rural farm house. 6. It was concluded that the final thermal efficiency of the conventional farm house was 10.6% lower than that of experimental farm house.

• Journal of Soil and Groundwater Environment
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• v.17 no.6
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• pp.52-58
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• 2012

Capillary fringe divides the groundwater and the vadose zone controlling the diffusive mass transfer of contaminants and gases. The thickness of capillary fringe is of great importance for the rate of contaminant mass transfer across the capillary fringe. Application of surface active chemicals including surfactants and alcohol-based products into the subsurface environment changes the surface tension of the aqueous phase, which in turn, affects the thickness of the capillary fringe. In this study, a bench-scale model was used to assess the quantitative relationship between the surface tension and the thickness of the capillary fringe. An anionic surfactant (Sodium dodecylbenzene sulfonate, SDBS) and an aqueous solution of ethanol were used to control the surface tension of the groundwater. It was found that the thickness of the capillary fringe is directly proportional to the surface tension. The air entry pressures measured by the Tempe Pressure Cell at different surface tensions using SDBS (200 mg/L) and ethanol (20%, v/v) solutions were in good agreement with the thicknesses of the capillary fringe measured by the model. A simple method to correct the conventional Brooks-Corey model for estimating the air entry pressure was also presented.