• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.4C
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• pp.175-183
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• 2010

The load distribution and deflection of large diameter piles are investigated by lateral load transfer method (p-y curve). The emphasis is on the effect of the soil continuity in a laterally loaded pile using 3D finite element analysis. A framework for determining a p-y curve is calculated based on the surrounding soil stress. The parametric studies that take into account the soil continuity are also presented in this paper. Through comparisons with results of field load tests, it is found that the prediction by the present approach is in good agreement with the general trend observed by in situ measurements and thus, represents a significant improvement in the prediction of a laterally loaded pile behavior. Therefore, a present study considering the soil continuity would be more economical pile design.

• Journal of Environmental Science International
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• v.21 no.2
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• pp.181-188
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• 2012

Salicornia europaea (glasswort) is succulent, annual, halophytic plant mainly distributed throughout reclaimed land or salt marsh. It has strong tolerance to salt so that it plays the part of the pioneer species in the first succession. According to domestic and foreign studies, S. europaea contains plenty of minerals and antioxidant in the body. Since people take note of an availableness of this plant as health diet, the natural growth sites are threatened. In addition to development of salt marsh and sea shore, imprudent harvest has a bad effect to S. europaea population maintenance. To seek ways to preserve the population of this plant, we carried out the continuity of seed germination and restoration test. Seokmo Island, Daebu Island, Youngjong Island and Sudokwon landfill in Korea are selected sites for research. Result of germination continuity shows that most S. europaea seeds germinate on March but no more after July. However the germination was occurred after that time in the greenhouse. So we concluded that no germination after July is a matter of environmental condition not the number of remaining seeds. Also germination was seldom occurred in the spot where seeds production was not happened. In result of continuity test of seed germination by soil depth, germination was occurred vigorously only in top soil. From these results, we note that most S. europaea germinate in the early spring, and germination is finished by July. And this rapid germination speed makes the number of seeds in soil seed bank rare. If a large number of S. europaea in some area are harvested after July, the number of this species will dramatically decrease in that area the following year. In Seokmo Island, we carried out reintroduction experiment by sowing S. europaea seeds. On the first year, a small number of S. europaea settled and they produced seeds successfully. On April 2010, the second year, we observed many S. europaea in seed sowing sites. And we found out that plowing is more efficient than treatment sea water for settlement of S. europaea.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.45-50
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• 2001

The purpose of this study was to estimate of soil loss form hillslope using WEPP(Water Erosion Prediction Project) model. WEPP model was developed for predicting soil erosion and deposition, fundamentally based on soil erosion prediction technology. The model for predicting sediment yields from single storms was applied to a tested watershed. Surface runoff is calculated by kinematic wave equation and infiltration is based on the Green and Ampt equation. Governing equations for sediment continuity, detachment, deposition, shear stress in rills, and transport capacity are presented. Tested watershed has an area of 0.6ha, where the runoff and sediment data were collected. The relative error between predicted and measured runoff was $-16.6{\sim}2.2%$, peak runoff was $-15.6{\sim}2.2%$ and soil loss was $-23.9{\sim}356.5%$.

• Korean Journal of Agricultural and Forest Meteorology
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• v.1 no.1
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• pp.29-35
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• 1999

Soil structure and organic matter have been known to strongly affect water flow and solute transport, yet little information is available concerning soil hydraulic properties related to soil physical and chemical properties in the forest site. The purpose of this study was to quantify the spatial variability and spatial correlation of the measured parameter values from the plots established with the rainfall simulator on Japanese larch(Larix leptolepis) dominated site in Kwangju. Kyunggi-Do. Measurement of soil water flux and retention were made with the inherent soil texture, soil structure, and organic matter. The method was based on the observation that when water was applied at a constant rate to the soil surface on each plot. The method was simple to apply and consists of following steps: (i) Wet the soil from a rainfall simulator with several known discharge rates on a relatively leveled soil surface with and without organic matter. (ii) Once the borders of the ponded zone were steady, saturated hydraulic conductivity( $K_{s}$) and the matric flux function(F) was evaluated from a regression of flux vs. the reciprocal of the ponded area. A conductivity of the form $K_{i+}$$_1$ $_{c}$= $K_{i}$( $_{c}$) [1-d /dz] where flux continuity implies. For this, continuity of matric potential at the interface at all times are as follows: $_1$( $Z_{c}$) = $_2$( $Z_{c}$) = $_{c}$ for steady state intake from water ponded on the soil surface. Results of this investigation showed the importance of understanding spatial variability in wide differences of water retention and saturated hydraulic conductivity with respect to pore geometry and organic matter contents which influenced the water flux throughout the soil profile.l profile.ile.

• Economic and Environmental Geology
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• v.25 no.2
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• pp.145-151
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• 1992

In order to study the optimum depth for the soil geochemical exploration in the area which is affected by agricultural activities and waste disposal of metal mine, the soil samples were sampled from the B layer of residual soil and vertical 7 layers up to 250 cm in the rice field and 3 layers up to 90 cm in the ordinary field. They were analyzed for Au, As, Cu, Pb and Zn by AAS, AAS-graphite furnace and ICP. To investigate the proper depth for the soil sampling in the contaminated area, the data were treated statistically by applying correlation coefficient, factor analysis and trend analysis. It is conclude that soil geochemical exploration method could be applied in the farm-land and a little contaminated area. The optimum depth of soil sampling is 60 cm in the ordinary field, and 150~200 cm in the rice field. Soil sampling in the area of a huge mine waste disposal is not recommendable. Plotting of geochemical map with factor scores as a input data shows a clear pattern compared with the map of indicater element such as As or Au. The second or third degree trend surface analysis is effective in inferring the continuity of vein in the area where the outcrop is invisible.

• Korean Journal of Hydrosciences
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• v.5
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• pp.1-16
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• 1994

In this paper distributed models for simulating spatially and temporally varied moving storm in a watershed were developed. The complete simulation in a watershed is achieved through two sequential flow simulations which are overland flow simulation and channel network flow simulation. Two dimensional continuity equation and momentum equation of kinematic approximation were used in the overland flow simulation. On the other hand, in the channel network simulation two types of governing equations which are one dimensional continuity and momentum equations between two adjacent sections in a channel, and continuity and energy equations at a channel junction were applied. The finite difference formulations were used in the channel network model. Macks Creek Experimental Watershed in Idaho, USA was selected as a target watershed and the moving storm on August 23, 1965, which continued from 3:30 P.M. to 5:30 P.M., was utilized. The rainfall intensity fo the moving storm in the watershed was temporally varied and the storm was continuously moved from one place to the other place in a watershed. Furthermore, runoff parameters, which are soil types, vegetation coverages, overland plane slopes, channel bed slopes and so on, are spatially varied. The good agreement between the hydrograph simulated using distributed models and the hydrograph observed by ARS are Shown. Also, the conservations of mass between upstreams and downstreams at channel junctions are well indicated and the wpatial and temporal vaiability in a watershed is well simulated using suggested distributed models.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.952-956
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• 2004

The soil-structure interactions are caused by the point sources of explosions, deriving piles, compaction of foundations and excavations those are frequently arose in the construction sites. Thus the analysis of soil-structure interactions is one of the most important subjects in the fields of dynamic analysis and vibration control. From this viewpoint, the aim of this study is to collect the basic data for designing foundation structures throughout understanding the dynamic structural behavior, which is embodied by the dynamic analysis of soil-structure systems. In this study, the dynamic analyses of stiffened thick plates subjected to in-plane stress on elastic foundations are carried out. The foundation is modeled as Pasternak foundation that includes the continuity effect of foundations. Also both the Mindlin plate theory and Timoshenko beam-column theory are used for analyzing the thick plates and beams, respectively.

• Structural Engineering and Mechanics
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• v.42 no.3
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• pp.353-362
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• 2012

In this paper decay and mapped elastodynamic infinite elements, based on modified Bessel shape functions and appropriate for Soil-Structure Interaction problems are described and discussed. These elements can be treated as a new form of the recently proposed Elastodynamic Infinite Elements with United Shape Functions (EIEUSF) infinite elements. The formulation of 2D horizontal type infinite elements (HIE) is demonstrated, but by similar techniques 2D vertical (VIE) and 2D corner (CIE) infinite elements can also be formulated. It is demonstrated that the application of the elastodynamical infinite elements is the easier and appropriate way to achieve an adequate simulation including basic aspects of Soil-Structure Interaction. Continuity along the artificial boundary (the line between finite and infinite elements) is discussed as well and the application of the proposed elastodynamical infinite elements in the Finite Element Method is explained in brief. Finally, a numerical example shows the computational efficiency of the proposed infinite elements.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.3
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• pp.213-219
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• 1992

Geomorphological properties for the phylite-derived soil were examined to relate processes to four landscape positions, shoulder, backslope, footslope, and toeslope in Chungbuk. The distribution of Ogcheon-geology system was 216 thousand ha in South Korea. 2 orders, 3 suborders, 4 great groups, 5 subgroups, and 9 series were mapped. Soil color was interlocked by landscape. Soil color index values and $Fe_2O_3$ contents increased with soil-drainge class. Silt/clay and Ca/Mg ratios tended to narrow wish elevation and decreased with depth. Therefore, profile development or age on the landscape position was shoulder>backslope>footslope>toeslope. Color index(C2m) has a sighificant correlation with $Fe_2O_3$, in soil profile($r=0.777^{**}$). Pedologic type was continuity/discontinuity and soil property changes of depth<12cm would have a continous function.

• Journal of the Korean Geotechnical Society
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• v.30 no.12
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• pp.41-49
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• 2014

The 3D numerical analysis is carried out to investigate the settlement behavior of flexible mat foundations subjected to vertical loads. Special attention is given to the improved analytical method (YS-MAT) that reflects the mat flexibility and soil spring coupling effect. The soil model captures the stiffness of the soil springs as well as the shear interaction between the soil springs. The proposed method has been validated by comparing the results with other numerical methods and a field measurement on mat foundation. Through comparative studies, the settlement of the proposed method was in relatively good agreement with those of a field measurement and other numerical methods. The results permit us to estimate the response of the mat foundation subjected to vertical loads that should be taken into account in the combination of mat flexibility and soil continuity characteristics.