풍화암에 근입된 영구 앵커의 극한인발력

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

The purpose of this study is to estimate ultimate uplift capacity of permanent anchor which was cast into weathered rock. The ultimate uplift capacity was estimated from the load-displacement curve of four different anchors which have different bond length. The creep test was performed for 15minutes under the maximum load of each step in order to understand the load-transfer property of permanent anchor and to decide which anchor to choose. The destruction range of soil due to the changes in load was estimated by installing dial gauge on the ground which was cast into the weathered rock. Ultimately, the study on the behavior of the anchor case into the weathered rock was performed by comparing and analyzing the estimated result of the UUC obtained by the full scale pull out test in the field with the exsting theoretical and practical results of soil and rock anchor.

모래다짐말뚝으로 개량된 연약지반의 응력분담특성

유남재,박병수,정길수,김상진 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 results of extensive centrifuge model experiments about design factors influencing the bearing capacity and the settlement behaviors of SCP (Sand Compaction Pile). Centrifuge model tests were carried out changing design factors for SCP method such as replacement area ratio (as= 20, 40, 70%), improvement ratio to footing width (W/B = 1, 2, 3), and amount of fines in sand pile (#200 = 5, 10, 15). Therefore, the effects of these design factors on the bearing capacity and the settlement behavior of SCP were investigated and changes of stress concentratio rato due to such an design factors were also investigated. Centrifuge model testing technique for preparing and installing centrifuge model of sand compaction pile, using freezing them, was also developed. As results of centrifuge model tests, more fines in sand compaction pile increases the bearing capacity of SCP. Optimum improvement ratio to footing width was found to be 2. Values of stress concentration ratio was in the ranges of 1.5 - 3.5. The depth of bulging in sand piles was found in the range of 2.0 - 2.5 times of pile diameter.

류마티스성 심장판막질환, 우심방혈전 및 대동맥 협착증과 합병된 만성 혈전색전성 폐동맥고혈압 1예

유근배,심준,임양희,이진화,신길자 梨花女子大學校 醫科大學 醫科學硏究所 1998 EMJ (Ewha medical journal) Vol.21 No.4

폐동맥 혈전색전증은 비교적 드문 질환으로 주로 심부 정맥혈전에서 발생하는 것으로 알려져 있으며 류마티스성 심장판막질환을 가진 경우 합병되는 우심방 혈전이 드물게 폐혈전색전증의 원인이 될 수 있는데, 저자들은 대동맥의 동맥경화성 협착증을 동반한 류마티스성 심판막질환 환자에서 우심부전 및 우심방혈전에서 발생한 만성 혈전색전성 폐동맥고혈압1예를 경험하였기에 문헌고찰과 함께 보고하는 바이다. Most pulmonary thromboemboli arise from the deep vein thrombosis, which have complete clinical and at least near complete roentgenographic and angiographic resolution within four to six week of the acute event. But chronic pulmonary hypertension and cor pulmonale from unresolved pulmonary embo-lism complicate acute embolic episode with a frequency of less than 1 percent. Rarely pulmo-nary thromboemboli can result from right atrial thrombi. We experienced a case of chronic thromoboembolic pulmonary hypertension, which wrose from right atrial thrombi in the patient with rheumatic valvaular heart disease and thoracic aorta atherosclerotics stenosis.

Sheet Pile 설치에 따른 SCP개량지반의 거동

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

The paper is to show the behavior of composit ground which is installed with sheet pile in soft soil improved by sand compaction pile. The results of load-settlement relationship, earth pressure, stress concentration characteristics, and final water content were obtained by centrifuge model test. Two cases of tests, installation of sheet pile on the corner and both side of the loading plate for the improved SCP ground which was designed twice of the footing width, were performed for the tests under the vertical and horizontal loading and both side of corner. Finite element program(CRISP) for sand compaction pile using elasto-plastic model and numerical analysis for soft soil using modified cam-clay constitutive equation were compared and analized with the results of model tests. The result of analysis show the increased bearing capacity of soil after, SCP and sheet pile was installed.

모래다짐말뚝의 원심모델링

유남재,정길수,김상진,채승호 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 results of extensive centrifuge model experiments about design factors influencing the bearing capacity and the settlement behaviors of SCP (Sand Compaction Pile). Centrifuge model tests were carried out changing design factors for SCP method such as replacement area ratio (as= 20, 40, 70%), improvement ratio to footing width (W/B = 1, 2, 3), and amount of fines in sand pile (#200 = 5, 10, 15). Therefore, the effects of these design factors on the bearing capacity and the settlement behavior of SCP were investigated and changes of stress concentratio rato due to such an design factors were also investigated. Centrifuge model testing technique for preparing and installing centrifuge model of sand compaction pile, using freezing them, was also developed. As results of centrifuge model tests, more fines in sand compaction pile increases the bearing capacity of SCP. Optimum improvement ratio to footing width was found to be 2. Values of stress concentration ratio was in the ranges of 1.5 - 3.5. The depth of bulging in sand piles was found in the range of 2.0 - 2.5 times of pile diameter.

배수재의 직경과 형상변화가 수평진공배수에 미치는 영향

유남재,박병수,정길수,이병곤 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.A

This paper is experimental results of investigating the efficiency of horizontal vacuum drainage system. Effects of size and shape of drain on horizontal vacuum drainage were studied. Model tests in the laboratory with soft marine clay were carried out with drain pipe of having three different diameters and PBD (Plastic Board Drain) of strip shape so that consolidation settlement of soft clay due to applied vacuum pressure, amount of discharge, around settlement and distributions of pore pressure and undrained shear strength were measured during testing. From results of model test, amount of discharge due to vacuum pressure was increased with the diameter of pipe drain whereas the drain efficiency of pipe in per unit area of drain surface was decreased with diameter of pipe. The rate of discharge per unit time was reduced verb fast with diameter of pipe. Settlement of ground surface with time was increased with diameter of pipe as a result of increase of discharge to drain pipe.

원심모형시험에 의한 사석재의 내부마찰각 추정

유남재,박병수,정길수,이종호 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 work of estimating friction angle of very coarse grained soil such as rubble mound by performing laboratory experiments. Two crushed rocks of rubble mound were used for tests. Triaxial compression tests with drained conditions were performed to measure friction angles of soils prepared by mixing the crushed soil having an identical coefficient of uniformity with different maximum grain size distribution. Centrifuge model experiments with those soils were also performed to measure angle of repose and to estimate friction angle of soil from measuring the slope of slip line in the active stress state. Model tests were carried out by changing the G-levels of 1G and 50G. From triaxial compression tests, the measured value of friction angle of soil is in the range of 41∼57˚. The measured value of repose angle is in the range of 32∼35˚. The values of friction angle are found not so sensitive to the maximum grain size of soil as long as the coefficient of uniformity is identical. Estimated value of friction angle from measuring the slope of slip line in the active stress state is in the range of 30~46˚. Thus, the estimated angle of friction are found to be greater in the order of the measured angle of repose, the estimated value from the slope of active state, and triaxial compression test results. On the other hand, the measured values of friction angle from triaxial tests were compared with empirical equations, based on the relation between friction angle and void ratio. Equations proposed by Helenelund(1966) and Hansen(1967) found to be relatively reliable to estimate friction angles of soil.

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.

모래다짐말뚝과 널말뚝으로 처리된 연약점토지반의 거동

유남재,정길수,박병수,김경수 강원대학교 산업기술연구소 2006 産業技術硏究 Vol.26 No.B

Centrifuge model experiments were performed to investigate the confining effects of the sheet piles, installed to the sides of soft clay ground treated with sand compaction piles, on the bearing capacity and concentration ratio of composite ground. For the given g-level in the centrifuge model tests, replacement ratio of SCP and the width of surcharge loads on the surface of ground with SCP, the confining effects of installing the sheet piles on the edges of SCP ground on the bearing capacity, change of stress concentration ratio and failure mechanism were investigated. Kaolin, one of typical clay mineral, and Jumunjin standard sand were used as a soft clay ground and sand compaction pile irrespectively. As results of experiments, lateral confining effect by inserting the model sheet piles fixed to the loading plate was observed. For the strip surcharge loading condition, the yielding stress intensity in the form of the strip surcharge loads tends to increase with increasing the embedded depth of sheet piles. The stress concentration ratio was found not to be influenced consistently with the embedded depth of sheet piles whereas the effect of stress intensity on stress concentration ratio shows the general trend that values of stress concentration ratio are relatively high at the initial stage of loading and tend to decrease and converge to the certain values. For the failure mechanism in the case of reinforced with sheet piles, displacement behavior related to the punching failure, settlement right beneath the loading plate occurred since the soil was confined with sheet piles, was observed.

준설매립토지반의 압밀침하량 예측

유남재,박병수,정길수 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.A

For soils with high void ratios, the inverse method of utilizing results obtained from centrifuge model test was used to find the constitutive relation of effective stress - void ratio - permeability whereas conventional oedometer test arid constant rate of strain consolidation test were also used to fine its relation at ranges of relatively low void ratio. Results of column test about settlement of interface and pore pressure and distribution with time were compared with numerically estimated values to confirm such a constitutive relation as obtained from the inverse method. Consolidational settlement in dredged and reclaimed ground, where the consolidation was in progress, was predicted by using the numerical technique implemented with the finite strain consolidation theory.