원심모형시험에 의한 편심하중을 받는 얕은기초의 거동

유남재,이명욱,박병수,정길수 江原大學校 産業技術硏究所 2002 産業技術硏究 Vol.22 No.A

This paper is an experimental and numerical work of investigating the bearing capacity of shallow foundation of rubble mound under eccentric loads. Parametric centrifuge model tests at the 50g level environments with the model footings in the form of strip footing were performed by changing the loading location of model footing, relative density and materials for ground foundation. For the model ground, crushed rock sampled from a rocky mountain was prepared with a grain size distribution of having an identical coefficient of uniformity to the field condition. Model ground was also prepared with relative densities of 50 % and 80 %. For loading condition, model tests with and without eccentric load were carried out to investigate the effect of eccentric loads and a numerical analysis with the commertially available software of FLAC was performed. For numerical estimation with FLAC, the hyperbolic model of a nonlinear elastic constitutive relationship was used to simulate the stress-strain constitutive relationship of model ground and a series of triaxial compression test were carried out to find the parameters for this model. Test results were analyzed and compared with Meyerhof method (1963), effective area method based on the limit equilibrium method, and a numerical analysis with FLAC.

과재하중 재하에 따른 역 T형 옹벽의 활동거동에 관한 수치해석

유남재,이명욱,박병수,이승주 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.B

This paper is experimental and numerical research about the sliding behavior of cantilever retaining walls resisting surcharge loads. In experimental research, centrifuge model tests at the 1g and 40g-level were performed by changing the location of model footing and its width. Bearing capacity of model footing and characteristics of load-settlement and load-lateral displacement of retaining wall were investigated. Test results of bearing capacity were compared with modified jarquio method, based on the limit equilibrium method with elasticity theory. For the numerical analysis, the commericially available program of FLAC was used by implementing the hyperbolic constitutive relationships to compare with test result about load-settlement and load-displacement of retaining wall, bearing capacity of strip footing.

상재하중에 의한 연약점토의 일차원 압밀에 관한 원심모형실험

유남재,이명육,이종호 江原大學校 産業技術硏究所 1997 産業技術硏究 Vol.17 No.-

This thesis is to investigate the one-dimensional consolidation behavior of soft marine clay with uniform surcharges by performing numerical and experimental works. Parametric experimental works of centrifuge model test were carried out changing test conditions of gravitational level in centrifuge, magnitude of surcharges and construction sequence of applying surcharges. Results of centrifuge model experiments were analyzed by using the numerical technique of explicit finite difference method based on the finite strain consolidation theory, being known to be appropriate to analyze the consolidational behavior of soft clay with a very high initial void ratio using the Lagrangian and the material coordinate systems. Test result were in relatively good agreements with analyzed results in terms of excess pore pressure dissipation and consolidation settlement with time and final void ratio distribution.

건조효과를 고려한 준설매립토의 압밀거동

유남재,박병수,이명욱,이주원 강원대학교 산업기술연구소 2000 産業技術硏究 Vol.20 No.A

This research is to investigate the self-weight consolidation settlement and desiccation shrinkage settlement of soft marine dredging clay by performing numerical and experimental works. Large column test were carried out investigate the consolidation settlement considering effect of the self-weight and desiccation shrinkage, and centrifuge model test was also carried out investigate self-weight consolidation settlement. Results of centrifuge model and large column experiments about changes of settlement with time were analyzed by using the numerical technique of explicit finite difference method considering effect of the self-weight and desiccation based on the finite strain consolidation theory. Centrifuge model test results were in relatively good agreements with analyzed results in terms of self-weight consolidation settlement with time. Large column test results showed quite different values from the numerically estimated one, carried by experimental conditions.

터널의 지보방법에 관한 遠心模型實驗

유남재,이명욱,박병수 江原大學校 産業技術硏究所 2002 産業技術硏究 Vol.22 No.B

This research is experimental thesis to prepare the structural safety of the upper bridge for support type on tunnel and the effect of settlement. Unit weight test and uni-axial compression test have been performed to simulate the physical property of foundation on the tunnel. Tunnel model of slip form type for centrifuge model has been developed to performed the tunnel excavation while field stress is activated. And the support type of tunnel such as umbrella arch method and large diameter steel pipe reinforce method has been tested for the centrifuge model. After the analysis of experiment, results show that internal displacement of large diameter steel pipe reinforce method is smaller than that of the umbrella arch method.

슬래그 다짐말뚝의 원심모델링

유남재,박병수,정길수,이명욱 江原大學校 産業技術硏究所 2002 産業技術硏究 Vol.22 No.B

This paper is experimental and numerical research results of performing centrifuge model tests to investigate the geotechnical engineering behavior of slag compaction pile as a substitute of sand compaction pile. In order to find the geotechnical engineering characteristics of the soft clay and the slag used in centrifuge model experiments, basic soil property tests, consolidation test, permeability tests and triaxial compression tests were performed. For centrifuge model tests, slags with changing relative density were used and their bearing capacity, stress concentrations in between pile and soft clay, settlement characteristics, and failure modes were investigated. As a results of centrifuge model tests, it was found that the bearing, capacity of model was increased with increasing density of slag pile and general shear failures were occured. Miniature soil pressure gauges were installed on model pile and soft ground respectively and thus vertical stress acting on them were measured. Stress concentration ratio was found to be in the range of 2.0∼3.0. Bearing capacity obtained from the model test with slag was greater than that from the model test with a sand having the identical layout to each other. Thus it was confirmed the slag was an appropriate substitution of pile for sand.

준설토의 건조수축에 의한 강도증가 특성과 지지력에 관한 연구

유남재,이종호,이명욱,김현주 강원대학교 산업기술연구소 2000 産業技術硏究 Vol.20 No.A

This research is results of experimental and numerical works on characteristic of strength increase and bearing capacity in dredged and reclaimed soil due to desiccation shrinkage. For a soil sampled from southern coastal area in Korea, basic soil property tests and standard consolidation test with falling head permeability tests were carried out to obtain consolidational characteristics of soil. Double cone penetration test. laboratory vane test and unconfined compression test were also performed to investigate the change of shear strength with degree of desiccation. Model tests were performed in 1G environment and 30G level artificially accelerated condition by using the centrifuge model test facilities to investigate the bearing capacity of desiccated ground. Test results were analyzed by using the bearing capacity of desiccated ground. Test results were analyzed by using the theoretical and load-settlement characteristics method proposed by Meyehof & Hanna(1978). On the other hands, the numerical technique, using the finite strain consolidation theory considering the effect of desiccation was used to estimate the appropriate time of using heavy construction equipments in field with respect to strength increase due to desiccation.

전기화상 환자에 대한 임상적 고찰

유병대,김성진,이명갑,서영조,강재구,이동필 대한응급의학회 2000 대한응급의학회지 Vol.11 No.4

Background: Good documentation of electrical injuries at the time of presentation is very important to emergency management, so this study was designed to investigate the clinical characteristics and the outcomes of patients with electrical injury. Methods: A review of 75 cases of electrical injuries admitted to our hospital via the emergency department over a 4 year period from 1996 to 1999 was conducted. Results: There were 49 patients with high-voltage injuries and 19 patients with low-voltage injuries. All but 4 patients were males, with a mean age of 29.5 years. The most common type of injury was electrothermal burn. The most common point of entry was hand. The average size of burn wounds was 14.5% TBSA in the high-voltage group and 2.5% in the low-voltage group. Forty-nine(72.1%) of the injuries were work related. The number of patients with compartment syndrome was 19, and fasciotomies were performed in all but one patient. Myoglobinuria was noted in 22 patients, but no patient developed acute renal failure due to myoglobinuria. In the high-voltage group, 10 limb amputations were performed. Complication were observed in 12 patients. The most common complication was neurological injury. The average length of hospital stay was 50.7 days in the high-voltage group and 13.8 days in the low-voltage group. The overall mortality rate was 4.3%. Couclusion: Prevention of electrical injuries is very important. Education and compliance with safety measures, as well as basic knowledge and precaution in dealing with electricity, are essential to avoid these injuries.

모형실험에 의한 사질토 자반에서의 군말뚝 거동에 관한 연구

유남재,김영길,이명욱,정해운 江原大學校 産業技術硏究所 1995 産業技術硏究 Vol.15 No.-

The purpose of this paper is to analyze the bearing capacity, settlement and pile action of pile groups in cohesionless soil, based on a wide range of model test in laboratory. Model test were conducted with changing the variables affecting the behavior of group pile; Number of pile, Diameters, Spacings between piles and Arrangement of piles. Effects of these variables on group efficiency were investigated by analyzing test results. Test results were also compared with the existing analytical method and data obtained in-situ tests.

경사진 사석층의 지지력에 관한 원심모형실험 및 수치해석

이명욱,박병수,정길수,유남재 江原大學校 産業技術硏究所 2004 産業技術硏究 Vol.24 No.B

This paper is an experimental and numerical research works about the effects of the bearing capacity of sloped rubble mound on the density of rubble mound and the position of footing. Centrifuge model tests were performed to investigate the bearing capacity of rubble mound by changing the density of rubble mound and the location of loading in forms of strip loading to simulate the caisson. Materials of rubble mound used in the model tests were crushed rocks having similar value of uniformity coefficient to the value in field. Two different relative densities of 80% and 90% were prepared during tests. The dimens ions of centrifuge model were trapezoidal shape of model mound having the bottom width of mound, 30cm and height of mound, 10cm. Gravity level applied during the centrifuge test was 50G. Surcharge loading in the forms of strip loading was applied on the top of the sloped model mound. Tests were carried out by changing the position of loadi ng. The rigid model footing was located in the center of top of the model rubble mound and the edge of model footing was at the crest of mound. Test results were analyzed by using the limit equilibrium methods proposed by Meyer hof(1957) and Bowles(1982) and the numerical approach with FLAC being available commercially software. For the numerical estimations with FLAC, the rubble mound was simulated with the constitutive relationship of Mohr-Coulomb elasto-plastic model.