• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.1042-1050
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• 2008

In this study, SCP method was used by purpose to improve loose sand and soft clay that is drilled Sand Compaction Pile in underground. Settlement behavior of field analyzed through SCP method. When sand Compaction Pile drilled in clay, forming composite ground that foundation and Sand Compaction Pile behavior. According to SCP method can expect bearing capacity improvement, Settlement reduction, lateral flow protection. SCP increase the consolidation settlement of ground and it reduce settlement for that purpose increase liquefaction resistance, lateral Resistance. Because SCP had been widely used for sand. Area of Inchon-A by sand compose clay and silt to upper Ground and compose soft clay to under ground. After pre-loading, it measured settlement by extensometer and settlement extensometer that purpose of ground improvement with 13% in replacement ratio. The result analyzed settlement behavior is similar to Multi-layered Ground that it happened to elastic settlement at upper ground and to consolidation settlement at under ground.

• Journal of Wetlands Research
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• v.13 no.2
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• pp.243-263
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• 2011

In order to understand the sedimentary environment of the southern intertidal zone of Shihwa Lake, west coast of Gyeonggi-do, 10 surface and 2 core sediment samples were analysed for grain size, water content, AVS (Acid Volatile Sulfide), TOC (Total Organic Carbon), concentrations of metals (Al, Fe, Mn, Cu, As, Pb, Zn, Ni, Cd, and Cr). The surface sediments are generally poorly sorted (0.60~2.31 ${\phi}$) sandy Silt, slightly gravelly muddy Sand, silty Sand, Sand with mean grain size of 2.95 to 6.00 ${\phi}$. The sediments contain Al (1.54%), Fe (1.75%), Cu (9.1ppm), As (1.1ppm), Pb (18.8 ppm), Ni (11.0 ppm), Cd (0.02 ppm), and Cr (30.1 ppm) on the average. Heavy metals are concentrated less than ERL (Effect Range-Low), verified by NOAA (National Oceanic and Atmospheric Administration). In the core sediments, they are also less than the ERL. Based on the uniform vertical distribution of excess radioactivity of $^{210}Pb$, the core sediments seen to have been actively mixed biologically or rapidly deposited after the construction of Shi-Hwa Seawall. The 'enrichment factor' of metals, normalized to Al, shows that the upper sediments of 35 cm in depth are more polluted. infect was significant in 2 core sediment samples in 35 cm below layer.

• Journal of Soil and Groundwater Environment
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• v.15 no.3
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• pp.34-43
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• 2010

The fate of hydrophobic organic contaminants (HOCs) in ground water is highly affected by the distribution and property of the carbonaceous materials (CMs) in subsurface sediments. CMs in soils consist of organic matters (e.g., cellulose, fulvic acid, humic acid, humin, etc.) and black carbon such as char, soot, etc. The distribution and property of CMs are governed by source materials and geological evolution (e.g., diagenesis, catagenesis, etc.) of them. In this study, the distribution and property of CMs in subsurface sediments near the Imjin river in the Republic of Korea and HOC sorption property to the subsurface sediments were investigated. The organic carbon contents of sand and clay/silt layers were about 0.35% and 1.37%, respectively. The carbon contents of condensed form of CMs were about 0.13% and 0.45%, respectively. The existence of black carbon was observed using scanning electron microscopes with energy dispersive spectroscopy. The specific surface areas (SSA) of CMs in heavy fraction(HFrCM) measured with N2 were $35-46m^2/g$. However, SSAs of those HFrCM mineral fraction was only $1.6-4.3m^2/g$. The results of thermogravimetric analysis show that the mass loss of HFrCM was significant at $50-200^{\circ}C$ and $350-600^{\circ}C$ due to the degradation of soft form and condensed form of CMs, respectively. The trichloroethylene (TCE) sorption capacities of sand and clay/silt layers were similar to each other, and these values were also similar to oxidzed layer of glacially deposited subsurface sediments of the Chanute Air Force Base (AFB) in Rantoul, Illinois. However, these were 7-8 times lower than TCE sorption capacity of reduced layer of the Chanute AFB sediments. For accurate prediction of the fate of hydrophobic organic contaminants in subsurface sediments, continuous studies on the development of characterization methods for CMs are required.

• Geomechanics and Engineering
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• v.30 no.3
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• pp.247-258
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• 2022

A field velocity resistivity probe (FVRP) can measure compressional waves, shear waves and electrical resistivity in boreholes. The objective of this study is to perform the soil classification through a machine learning technique through elastic wave velocity and electrical resistivity measured by FVRP. Field and laboratory tests are performed, and the measured values are used as input variables to classify silt sand, sand, silty clay, and clay-sand mixture layers. The accuracy of k-nearest neighbors (KNN), naive Bayes (NB), random forest (RF), and support vector machine (SVM), selected to perform classification and optimize the hyperparameters, is evaluated. The accuracies are calculated as 0.76, 0.91, 0.94, and 0.88 for KNN, NB, RF, and SVM algorithms, respectively. To increase the amount of data at each soil layer, the synthetic minority oversampling technique (SMOTE) and conditional tabular generative adversarial network (CTGAN) are applied to overcome imbalance in the dataset. The CTGAN provides improved accuracy in the KNN, NB, RF and SVM algorithms. The results demonstrate that the measured values by FVRP can classify soil layers through three kinds of data with machine learning algorithms.

• Economic and Environmental Geology
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• v.49 no.4
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• pp.291-299
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• 2016

This study examined stratigraphic research containing extreme climate event during Quaternary period in Saban-ri, Haeri-myeon, Gochang by constructing 3D topographic model and 3D geological model. As a result of 3D topographic model and subsurface geological model, the geology of study area accumulated bedrock, Pleistocene series, and Holocene series chronologically. Most of the study area consist of bedrock on basement and Holocene series on upper layer. Additionally, Pleistocene series are presented as lens-shaped deposit on eastern part, and wedge-shaped deposit on northeastern part. Holocene layers consist of sand and clay-silt layer deposited sequentially where implies fluvial deposits on transgression environment. Distinctively, Pleistocene clayey silt layer and Holocene sand layer on eastern are observed as pond shape deposits that are considered as storm-related deposits originated from overwash system caused by extreme paleoclimate.

• Ocean Science Journal
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• v.41 no.3
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• pp.139-148
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• 2006

The distribution of the taxonomical composition and the density of meiobenthos depending on the sediment type has been studied in bottom sediments of Nha Trang Bay. The maximal population density and the taxonomical diversity were observed in the silted coarse and heterogeneous sand ($1031.4{\pm}419.7\;ind.\;10\;cm^{-2}$), whereas the minimal level of density and diversity ($588.1{\pm}152.5\;ind.\;10cm^{-2}$) was in the coarse and heterogeneous sand with shell debris and corals. The correlation between the median diameter of sediment particles and population density of meiobenthos has been revealed (r=0.82, p<0.05). In bottom sediments of Nha Trang Bay, twenty six taxonomic groups of meiobenthos were observed. Nematodes dominated in all sediment types. Representatives of four orders, twenty eight families and ninety seven genera of marine nematodes were identified. The vertical distribution of meiobenthos in different sediment types was considered. A sediment column (10 cm height) was sectioned by five 2 cm portions. In the last layer (8-10 cm) the most number of meiobenthic groups was found in sandy sediments. In the lower layers of silt sediments, only nematodes were found.

• Journal of the Korean Institute of Landscape Architecture
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• v.30 no.1
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• pp.87-95
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• 2002

This study was carried out to investigate the load of soil layers affected by soil depth in artificial soil alone or in blends with Loam with various ratio. The artificial soils were perlite large grain, perlite small grain, and perlite small grains blended with Loam (sand 46%, silt 40%, clay 14%) at a ratio of 8:2, 6:4, 5:5 (v/v). The soil layers were divided into a planting layer and a well-drained layer, then the weight of each layer in the air-dried state and in the field capacity were determined. The data were subjected to correlation analysis, regression analysis, and paired samples t-test. The summarized results are as follows; 1) In the air-dried state, the regression equations of the well-drained layer weight(kg/m2) in perlite large grain, planting layer weight in perlite small grain, planting layer weight in perlite small grain biended with loam(8:2, v/v), perlite small grain blended with loam(6:4, v/v), and perlite small grain blended with loam(5:5, v/v) were; 1.65824*X+0.026, 1.52292*X-0.052, 3.21468*X+0.515, 6.17549*X+ 0.083, and 6.02100*X + 33.133, respectively, where X is soil depth measured in Centimeters. 2) In the field capacity, the regression equations of the well-drained layer weight(kg/m2) in perlite large grain, planting layer weight in perlite small grain, planting layer weight in perlite small grain blended with loam(8:2, v/v), perlite small grain blended with loam(6:4, v/v), and perlite small grain blended with loam(5:5, v/v) were 5.055*X - 2.006, 7.073*X + 100.008, 8.092*X + 116.676, 10.766*X + 100.112, and 10.974*X + 124.423, respectively, where X is the soil depth measured in Centimeters. 3) All of the equations mentioned above were statistically reliable and therefore easily applicable in practical business affairs.

• Magazine of the Korean Society of Agricultural Engineers
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• v.35 no.2
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• pp.43-56
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• 1993

The laboratory tests are performed on how the liquefaction potential of the sea dike structures on the saturated sand or silty sand seabed could be affected due to earthquake before and after construction results are given as follows ; 1. Earthquake damages to sea dike structures consist of lateral deformation, settlement, minor abnormality of the structures and differential settlement of embankments, etc. It is known that severe disasters due to this type of damages are not much documented. Because of its high relative cost of the preventive measures against this type of damages, the designing engineer has much freedom for the play of judgement and ingenuity in the selection of the construction methods, that is, by comparing the cost of the preventive design cost at a design stage to reconstruction cost after minor failure. 2. The factors controlling the liquefaction potential of the hydraulic fill structure are magnitude of earthquake(max. surface velocity), N-value(relative density), gradation, consistency(plastic limit), classification of soil(G & vs), ground water level, compaction method, volumetric shear stress and strain, effective confining stress, and primary consolidation. 3. The probability of liquefaction can be evaluated by the simple method based on SPT and CPT test results or the precise method based on laboratory test results. For sandy or silty sand seabed of the concerned area of this study, it is said that evaluation of liquefaction potential can be done by the one-dimensional analysis using some geotechnical parameters of soil such as Ip, Υt' gradation, N-value, OCR and classification of soils. 4. Based on above mentioned analysis, safety factor of liquefaction potential on the sea bed at the given site is Fs =0.84 when M = 5.23 or amax= 0.12g. With sea dike structures H = 42.5m and 35.5m on the same site Fs= 3.M~2.08 and Fs = 1.74~1.31 are obtained, respectively. local liquefaction can be expected at the toe of the sea dike constructed with hydraulic fill because of lack of constrained effective stress of the area.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.04a
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• pp.513-516
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• 2003

This study was performed in two ways, which are 'Before' 'After' carrying out trench search through GPR which is called 'Non Destructive Geophysical' to the expected area where the remains of historic interest could be distributed within the construction site from Dae-gu to Busan. As a result, the layer containing gravel and sand has more irregular specular surface then others containing silt and clay. And, this paper, irregular specular surfaces of prominence and depression patter appeared. After performing trench search, verified that the site yield dolmens and lots of stone implements.

• Journal of Korean Society for Geospatial Information Science
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• v.11 no.1 s.24
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• pp.45-49
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• 2003

This study was peformed in two ways, which are 'Before' 'After' carrying out trench search through GPR which is called 'Non Destructive Geophysical' to the expected area where the remains of historic interest could be distributed within the highway construction site from Dae-gu to Busan. As a result, the layer containing gravel and sand has more irregular specular surface then others containing silt and clay, And, apart block irregular specular surfaces of prominence and depression patter appeared. After performing trench search, verified that the site yield dolmens and lots of stone implements.