• 한국터널지하공간학회 논문집
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• 제22권1호
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• pp.135-144
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• 2020

국내에서 TBM 공법을 활용한 터널건설 시 점차 건설심도가 깊어지고 있으며, 이로 인해 상부 지반조사 단계에서 충분한 예측 정확도를 획득하기 위해서는 시추조사 및 물리탐사 비용이 증가하게 된다. 이러한 문제를 극복하기 위해 터널 시공 중 터널 굴착면 전방 예측을 위한 방법들이 제시되었다. 프로브 드릴링을 활용한 굴착면 전방 예측은 코어회수, 시추공 내부 이미지 등을 활용할 수 있는 장점이 있지만 실제 TBM 내에 설치가 어렵고 터널 막장 전체가 아닌 국부적인 지반만을 파악할 수 있다. TSP 등 탄성파를 활용한 방법은 100 m 이상의 긴 탐사거리를 가지지만 신호발생을 위해 발파를 사용하므로 세그먼트 라이닝, 백필 등의 안정성에 영향을 미칠 수 있다. TEPS를 포함한 전자기파 탐사는 지하수 층 등 전도성 있는 이상대를 파악하는 데 적합하지만 소구경 TBM에 설치할 수 있는 전극의 개수가 한정적이며 이는 탐사 범위의 감소 등을 야기한다. 본 연구에서는 전기비저항 탐사 시 굴착면에 설치되는 전극의 개수를 최소화하기 위해 TBM의 굴착면과 측면에 전극이 설치되었을 때에 대한 탐사 이론식을 제시하고 실내실험을 통해 검증하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 봄 학술발표회 논문집
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• pp.781-788
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• 2003

It is an essential process to predict behaviors of ground and structure to seek economical efficiency and stability on the given environment. Predictions are conducted through analysis process of ground and structure. For these analyses, exact and quick acquisition of measuring data is required. But we face many difficulties in data acquisition stages due to the conditions of construction site. Therefore development of a powerful and effective monitoring system that can manage the integration of database and the implementation of measuring process in real time is strongly desired. This article shows an actual example of application of internet based monitoring system compared with the conventional monitoring system.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 사면안정학술발표회
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• pp.119-127
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• 2003

For the calculation of internal stability, the hypothesis in conventional design is on the basis of two distinct zones, which are‘active zone’and‘passive zone’. This means that there is an abrupt discontinuous transition from active to passive states across a potential failure line. The existence of a discontinuity of this nature appears physically unreasonable, especially from kinematic considerations. A series of pull-out model tests was undertaken from a wall being rotated about the toe to find the strain distribution mobilized from near the wall face into the deep, stable zone through the centre plane. With this finding of transition zone, the objective of study is aiming at identifying the likely effect of this zone in designing method by comparing with the prevailing design method.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.960-964
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• 2011

High speed railway structure, contact of vehicle needs to design considering the running stability(dynamic behavior). Also, upper structure has to satisfy design standard about moving load, high speed train(KTX). So, the high speed railway structure has to satisfy the requirement of natural frequency, vertical acceleration on deck, face distortion and vertical displacement considering ride comfort, which is suggested Ho-nam high speed railway design standard. In this study, it was investigated and evaluated to the dynamic behavior for tow plate Girder railway bridge subjected to moving load considering real high speed train loads.

• Restorative Dentistry and Endodontics
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• 제37권3호
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• pp.180-184
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• 2012

Traumatic injuries of the face often involve root fractures especially in anterior teeth. The prognosis and the treatment of the root fracture depend on the extent of the fracture line, general health and patient compliance. This case report outlines a new conservative trial treatment modality to stabilize the maxillary central incisors with horizontal root fracture on the cervical to middle third by fabricating canine guidance to remove loading on the traumatized maxillary central incisors during eccentric movements and thus inducing spontaneous healing of the fractured line between the fragments. Radiographs after thirty months showed adequate healing with no signs of pathological changes including root resorption, ankylosis or displacement. Long term follow-up revealed that vitality, stability and aesthetics were maintained and the patient was satisfied with the outcome.

• 화약ㆍ발파
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• 제12권1호
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• pp.32-38
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• 1994

This study Is to summarize the contents for the investigation and design of the construction for oil storage. Since underground caverns are large scale, in their construction one should consider the mechanical stability of cave·rns and the economic view of construction. On the basis of them, cavern's section and layout were determined and water curtains were designed to maintain hydraulic equilibrium so that gases were sealed tightly. Also the supporting criteria for rock bolt and stotcrete were determined by means of the classification of rock masses and the results of finite element method. The criteria of grouting reinforcement were presented according to the results of injection test in the pilot holes of working face.

• 터널과지하공간
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• 제3권1호
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• pp.80-95
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• 1993

Convergence measurements play very important role in the assessment of stability of a tunnel and of the economics of rock reinforcements. The characteristics of convergences are both due to the face advance effect and the time-dependent behaviour of rocks. As the convergence law can be modeled as a specific function of two variables of distance and time, we can determine the type of function and the related parameters from the field measurements. By using the regression method based on the Levengberg-Marquardt algorithm, an analysis of convergence of two different tunnels and one numerical example is described. It is shown that the convergence can be modeled as following function, C(x)=a{1-exp(-bx)} or C(t)=a{1-exp(-bt)} in case of a tunnel excavated in elastic rocks, in case of elasto-plastic or over stressed rocks.

• 제어로봇시스템학회논문지
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• 제6권8호
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• pp.672-681
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• 2000

Based on the dynamic anti-windup strategy a novel control methodology for state constrained control systems is presented. First a linear controller is designed for an open-loop stable plant to show a desirable nominal performance by ignoring state constraints. And then an additional dynamic compensator is introduced to preserve the nominal performance as closely as possible int he face of state constraints. This paper focuses on the second step under the assumption that a linear controller has already been designed appropriately by using an effective controller design method. By minimizing a reasonable performance index the dynamic compensator is derived explicitly which is expressed int he plant and controller parameters. the proposed method not only guarantees the total stability of the overall resulting systems but also provides desirable output performance because it solves the state-positioning problem completely.

• 한국정밀공학회지
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• 제1권2호
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• pp.47-57
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• 1984

The porous matterials are used both to control the flow of the compressed gas and to serve as the bearing surface. This porous design offers several advantages over the conventional externally pressurized gas bearings. It can simplify the construction, lower the gas consumption, and make the cleaning of the gas supply less critical. Test apparatus was cinstructed to experi- mentally investigate maximum load capacity of thrust bearing was measured 200 Kg (15Kg/$\mu$m), and radial bearing was 36 Kg/$\mu$m. And a rotation accuracy of face waving was 0.0127$\mu$m, and center waving was measured 0.5 $\mu$m. Finally, the use of this method of design and manufacturing will contribute to many practical application in the field required for precision and high stability.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.787-792
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• 2002

The voided slab have many advantages, light weight, high load-distribution capacity, low cost and beautiful appearance, etc. But they have also many cracks due to difficulties in designs and construction, analysis, shrinkage, installation and rising force of voided tube. This paper presents the retrofit effects with steel plate(SP)/carbon fiber sheet(CFS) of RC voided slab. As a results of this study, it proved that the strip pattern has to be profitable than full-face pattern in performance such as crack, ultimate loads, stiffness. Retrofit length has many influence on retrofit effects, as the length increases, performance and stability of end blocks higher. Also, it proved that the retrofit on full-section has to be profitable than voided-section in performance, and the overlay length of CFS is desirable to extent approximately and welding(V-cut) has to be efficient than anchors in SP connection. But the kinds of end block and anchor has not influence on retrofit effects.