• Korean Journal of Agricultural Science
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• v.12 no.2
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• pp.282-291
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• 1985

In order to investigate the settlement characteristics of fill dam with decomposed granite is used as a embankment material instead of conventional clay collected behavoir of Andong dam and analyzed. Andong dam is the use of decomposed granite in the embankment material, and various type of gauges were installed in dam to measure a pore pressure, interval vertical settlement, dam crest settlement, relative settlement, surface settlement and internal horizontal movement. The results were summerized as follows; 1. With the increase of embankment loading, the settlement of core zone during construction increased with linear and under the effective stress $7kg/cm^2$ vertical settlement ratio ranged between 0.1 and 0.8% approximately and showed smaller value than that of fill dam with clay were used as a embankment material. 2. Though embankment loading was increased with about over central part of embankment height, the settlement of core zone in the lower part of the embankment was influenced slightly. 3. Pore pressure responsed sensitively with the increase of coefficient of permeability in core zone and settlement increased with pore pressure were dispersed. 4. During construction relative settlement in the lower part of the embankment has the largest influence on magnitude of the relative density and after construction settlement showed larger value in the core zone which has the largest compression height. 5. Settlement distribution of dam crest showed larger value in the central part, maximum section of dam, but smaller value in near the abutment.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.16 no.1
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• pp.18-26
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• 2004

In order to accelerate the rate of consolidation settlement, to reduce settlement, and to increase bearing capacity for soft ground under quay, sand compaction pile method (SCP) has usually been applied. SCP-reinforced ground is composite soil which consists of the sand pile and the surrounding soft soil. One of main important considerations in design and analysis for SCP-reinforced soils is stress concentration ratio according to area replacement ratio. In this paper, the numerical analysis was conducted to investigate characteristics of stress concentration ratio in composite ground. It was found that stress concentration ratio of composite ground is not constant as well as depends on several factors such as area replacement ratio, depth of soft soil, and consolidation process. The values of stress concentration ratio increase during loading stage due to stress transfer of composite soil, and reach up to 2.5∼12 according to area replacement ratio at the end of construction. After the end of consolidation, however, these values are converged to 2.5 to 6.0 irrespective of area replacement ratio due to increase in effective stress of soft soil during consolidation process.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.4
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• pp.79-89
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• 2003

The purpose of this study is to investigate appropriate environmental factors when domestic waste is decomposed as aerobic digestion. So stabilization degree was measured after the waste is mixed as certain rates and water content was controlled by 55% and 60%. Variation of VS showed food waste in reactors of number 1, 2, 3, 4 and 5 was decomposed fully except reactor of number 6. Decomposition degree of VS in reactors of number 1, 2, 3 and 4 was not different high because Vinyl and plastic inserted played role bulking agent in reactor number 1, 2, 3 and 4. In reactors, maximum temperature indicated $57{\sim}59^{\circ}C$ and temperatures in reactors 1, 2, 3 and 4 were higher and remained longer than in reactor 5 and 6 for 2~4 days. Variation of $CO_2$ was similar to that of VS. The reduction rate of water content was low because moisture generated by oxidation fever of microorganism did not evaporated well. pH was low in the beginning of the reaction however, as time passed, it increased slightly and remained regular pattern. EC and C/N showed the same pattern as pH. Settlement and weight reduction rates were similar to the factors above. Reactor 1, 2, 3, and 4 showed higher settlement and weight reduction rate than reactor 5 and 6.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.907-917
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• 2014

When conducting excavations after burying the soft ground, even if the retaining walls are installed, failure often occurs within backfill. In order to minimize the occurrences of failures, model test was performed after the installation of stabilizing piles to investigate the stabilizing effects. The model chamber is set up with clay foundation reinforced with and without stabilizing piles. During the excavation of clay foundation, the subsidence, pore water pressure, and soil pressure along the excavation were measured. As a result of the model test, the increase of excavation levels and the reduction of subsidence of back ground were observed with the stabilizing piles, compared to those without the stabilizing piles. The installation of stabilizing piles does not influence the pore water pressure change, but induces less subsidence rate. In addition, the depth of excavation has a significant effect on the back ground and it was evaluated that the maximum subsidence occurs as it is closer to the excavation point.

• Journal of the Korean Geotechnical Society
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• v.32 no.9
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• pp.29-36
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• 2016

Backfill materials of rail abutment were commonly composed with cement treated aggregate, general aggregate and soil. The friction angle of cement treated aggregate increased up to $40^{\circ}$ or more due to strength enhancement. However, $30^{\circ}{\sim}35^{\circ}$ of friction angle was typically applied for in-situ condition. This phenomenon could cause over-designing, therefore, it is essential to determine reasonable material properties of cemented treated aggregate. In this study, a series of CBR tests and circular model tests have been conducted for cement treated aggregate, while changing cement mixing ratio. Based on test results, characteristics of settlement and strength have been analyzed quantitatively. The settlement of cement treated aggregate decreased with the number of cyclic loading and aging period. In addition, The strength increment ratio in CBR test increased up to 13~16 times at 28 days aging.

• Journal of the Korean GEO-environmental Society
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• v.12 no.8
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• pp.33-38
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• 2011

Presently, domestic SCP method with low replacement ratio is required as alternative in order to overcome the profitability of the sand resource because of the deficiency phenomenon of the sand resource by the actual condition design and construction is made by SCP method with low replacement ratio more than 70% for the port construction in the safe side. Sand compaction pile(SCP) method has been mainly used to improve the properties of soft clay or loose sandy ground. In design of SCP at soft clay ground, it is very important to determine the stress concentration ratio of composite ground relevant to the area replacement ratio. In this study, 2-dimensional FEM analyses were carried out to evaluate the stress concentration ratio of composite ground depending upon the area replacement ratio. When the interpretation result replacement ratio was 30%, the stress assigned rate showed and as the replacement ratio was high, the stress assigned rate according to the sinkage showed the low stress assigned rate.

• Journal of the Korean GEO-environmental Society
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• v.14 no.9
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• pp.31-37
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• 2013

In this study installation diameter, interval, area replacement ratio and ground hardness of applicable ground in C.G.S method should be mastered through surrounding ground by conducting modeling. Optimum artificial neural network was selected through the study of the parameter of artificial neural network and prediction model was developed by the relationship with numerical analysis and artificial neural network. As this result, C.G.S pile settlement and ground settlement were found to be equal in terms of diameter, interval, area replacement ratio and ground hardness, presented in a single curve, which means that the behavior pattern of applied ground in C.G.S method was presented as some form, and based on such a result, learning the artificial neural network for 3D behavior was found to be possible. As the study results of artificial neural network internal factor, when using the number of neural in hidden layer 10, momentum constant 0.2 and learning rate 0.2, relationship between input and output was expressed properly. As a result of evaluating the ground behavior of C.G.S method which was applied to using such optimum structure of artificial neural network model, is that determination coefficient in case of C.G.S pile settlement was 0.8737, in case of ground settlement was 0.7339 and in case of ground heaving was 0.7212, sufficient reliability was known.

• Magazine of korean Tunnelling and Underground Space Association
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• v.23 no.3
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• pp.54-94
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• 2021

• Journal of the Korean GEO-environmental Society
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• v.24 no.1
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• pp.5-14
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• 2023

In this study, the load transfer characteristics of the base and skin of drilled shafts were analyzed and the load sharing ratio was calculated by performing a load transfer large-scale model test and three-dimensional numerical analysis considering the similarity of drilled shafts, which is the design target. From the linear behavior of drilled shafts shown in the large-scale model test and 3D numerical analysis results, the skin load transition curve for the design conditions of this study was proposed by Baquelin et al., and the base load transition curve was proposed by Baquelin et al. For the horizontal load transition curve, the formula proposed by Reese et al. was confirmed to be appropriate. The test value was slightly larger than the numerical analysis value for the axial load at the rock socketing, but the load sharing ratio at the rock socketing increased, on average, about 27.8% as the vertical load increased. The analysis value of the vertical settlement of the pile head under the vertical load was evaluated to be slightly smaller than the test value, and the maximum vertical settlement of the pile head in the model test and analysis maximum vertical load was 10.6 mm in the test value and 10.0 mm in the analysis value, and the maximum vertical settlement value at the base of the pile was found to be a test value of 2.0 mm and an analysis value of 1.9 mm. The horizontal displacement at the head of the column (ground surface) and the head of the pile during the horizontal load was found to agree relatively well with the test value and the analysis value. As a result of the model soil test, the horizontal load measured at the maximum horizontal displacement of 38.0 mm was evaluated to be 24,713 kN, and the horizontal load in the numerical analysis was evaluated to be 26,073 kN.

• Journal of the Korean GEO-environmental Society
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• v.15 no.1
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• pp.25-34
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• 2014

The aim of this study is to analyze the mechanical characteristics and settlement feature of the composite ground with structural form changes. The laboratory model test is a soil tanker to be contained with clay and grid form improved soil, which is conducted in total 9 case with the uniaxial compressive strength of improved soil and replacement ratio of improved soil. The numerical analysis for variation of stress distribution ratio with depth was performed in the same conditions which are the laboratory model test. As a result, stress distribution ratios in mid and high replacement ratio are increasing and settlement is decreasing, except low replacement ratio. This study is presented for form effect ratio and settlement reduction factor with change of structure form, which is able to be helpful in further research and reference for change of structural forms at composite ground.