• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.521-532
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• 2008

Supporting system design and construction management for the soft and hard rock layers with fractured zones are very important theme for the safety of temporary retaining wall, surrounding ground and structures in the urban deep excavation for the construction of subway, railway, building etc. The prevailing design method of supporting system for the soft and hard rock layers in the deep excavation is mostly carrying out by simplification without proper consideration for the characteristic of rock discontinuities. Therefore the behaviors of rock discontinuities and fractured zones dominate the whole safety of excavation work in the real construction stage, serious disaster due to the failure of temporary retaining wall can be induced in the case of developing large deformations in the ground and large axial forces in the supporting system. This paper introduces examples of deep excavation where the soft and hard rock layers with fractured zones were designed to be supported by shotcrete and rock bolt, deformations of corresponding ground and supporting systems in the construction period and increments of axial force in the upper earth anchors and strut due to the these deformations were investigated through detailed analysis of measurement data, the results were so used for the management of consecutive construction that led to the safe and economical completion of excavation work. The effort of this article aims to improve and develop the technique of design and construction in the coming projects having similar ground condition and supporting method.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.308-319
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• 2009

In the case of relatively good ground and construction condition in the deep excavation for the construction of subway, railway, building etc., flexible earth retaining systems are often used in an economical point of view. It is generally known that the mechanism of behavior in the flexible earth retaining system is relatively more complicated than the rigid earth retaining system. Moreover in the case of long span strut supporting system the analysis of strut axial force change becomes more difficult when the differences of ground condition and excavation work progress on both sides of excavation section are added. When deeper excavation than the specification or installation delay of supporting system is done or change of ground condition is faced due to the construction conditions during construction process, lots of axial force can be induced in some struts and that can threaten the safety of construction. This paper introduces two examples of long span deep excavation where struts and rock bolts were used as a supporting system with flexible wall structure. And the sections of two examples are 50 meters apart in one construction site, they have almost similar design and construction conditions. The characteristics of ground deformation and strut axial force change were analysed, the similarity and difference between measurement results of tow examples were compared and investigated. The effort of this article aims to improve and develop the technique of design and construction in the coming projects having similar ground condition and supporting method.

• 한국안전학회지
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• 제23권1호
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• pp.28-34
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• 2008

The corrugated steel plate structures is applied to the construction of mountain tunnel portal part with shallow depth, the tunnel on the outskirts of urban areas and ecology move passage. In this study, A finite element method is used for research the behavior of corrugated steel plate structures due to construction position under declinating earth pressure and excavation depth. A finite element method were performed varying construction position(10, 15, 20 and 25m) from slope and excavation depth from surface. The hoop thrust and moment, displacement of corrugated steel plate subjected to construction position and excavation depth is determined from a finite element method. From results of finite element method, it was found that the increase of thrust and the decrease of displacement as the amount of distance increase from slope with construction position. But the thrust and moment, displacement has not different value with excavation depth.

• Geomechanics and Engineering
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• 제19권3호
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• pp.283-293
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• 2019

Evaluating the stability of the excavation face of the cross-river shield tunnel with good accuracy is considered as a nonlinear and multivariable complex issue. Understanding the stability evaluation method of the shield tunnel excavation face is vital to operate and control the shield machine during shield tunneling. Considering the instability mechanism of the excavation face of the cross-river shield and the characteristics of this engineering, seven evaluation indexes of the stability of the excavation face were selected, i.e., the over-span ratio, buried depth of the tunnel, groundwater condition, soil permeability, internal friction angle, soil cohesion and advancing speed. The weight of each evaluation index was obtained by using the analytic hierarchy process and the entropy weight method. The evaluation model of the cross-river shield construction excavation face stability is established based on the idea point method. The feasibility of the evaluation model was verified by the engineering application in a cross-river shield tunnel project in China. Results obtained via the evaluation model are in good agreement with the actual construction situation. The proposed evaluation method is demonstrated as a promising and innovative method for the stability evaluation and safety construction of the cross-river shield tunnel engineerings.

• 한국지반환경공학회 논문집
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• 제19권1호
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• pp.31-36
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• 2018

최근 건축공사가 활성화됨에 따라 기존 구조물과의 근접한 공사 그리고 인접 굴착공사와 병행하여 굴착공사가 진행되는 환경이 증가하고 있지만 이에 대한 연구는 미흡한 실정이다. 본 연구에서는 두 개의 굴착 흙막이 구조물에 대해 기존 굴착 흙막이 구조물과 후속 굴착 흙막이 구조물 간의 상호작용 분석을 위해 수치해석을 수행하였다. 수치해석 분석결과 선행 굴착으로 인해 작용하는 지보재의 하중을 고려하지 않는 경우 구조물에 발생하는 변위는 과소평가 될 수 있는 것으로 분석되었고, 지보재에 작용하는 응력은 과하게 평가되어 실제 지반의 거동을 모사하기 위해서는 선행굴착으로 인해 발생하는 지보재 응력을 고려해야 하는 것으로 분석되었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.445-456
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• 2010

Massive underground excavation can be carried out recently due to the technical development of the excavation for retaining wall. Feed-back analysis using field measurement results is recommended to secure the stability of the construction because calculated values at stages of the design and the construction are uncertain. Reinforcement plan should be established based on the result of it. This study deals with the underground excavation site, which is under construction and is close to structure(subway) at downtown area. The result of feed-back analysis on the measurement data of displacement at multi-soil layers was reflected to make a plan for safe construction. This case study can be useful information for contingency plan on abnormal displacement which can be occurred at similar underground excavation.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.428-444
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• 2010

After underground excavation being introduced in dometic, many technologies have been storing up. One of them, measurement, has been recognized as an important item under excavation construction. But, unlike a large-scale construction, it was not been treated importantly at the general small-scale structures with poor ordering and original design was unchanged under construction was normal if the problem didn't occur on monitoring. In this paper, the site which safe and economical management as well as shortening construction period was made effectively using measurement result was introduced. Also, the site which was completed safely with analyzing measurement and reinforcement when unusual symptom happened was introduced. Using measurement result effectively will be able to obtain the safety and prevent unnecessary economical loss.

• Geomechanics and Engineering
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• 제34권2호
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• pp.115-124
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• 2023

By conducting three-dimensional simulation with consideration of small-strain characteristics of soil stiffness, the effects of excavation geometry and tunnel cover to diameter ratio on deformation mechanisms of an existing tunnel located either at a side of basement or directly underneath the basement were systematically studied. Field measurements were used to verify the numerical model and model parameters. For basement excavated at a side of an existing tunnel, the maximum settlement and horizontal displacement of the tunnel are always observed at the tunnel springline closer to basement and tunnel crown, respectively, regardless of basement geometry. By increasing basement length and width by five times, the maximum movements of tunnel located at the side of basement and directly underneath the basement increase by 450% and 186%, respectively. Obviously, tunnel movements are more sensitive to basement length rather than basement width. For basement excavated at a side of an existing tunnel, tunnel movements at basement centerline become stable when basement length reaches 10 H_e (i.e., final excavation depth). Moreover, tunnel heaves due to overlying basement excavation become stable when the normalized basement length (L/H_e) is larger than 8.0. As tunnel cover to diameter ratio varies from 2.5 to 3.0, the maximum heave and tensile strain of tunnel due to overlying basement excavation decrease by up to 41.0% and 44.5%, respectively. If basement length is less than 8 H_e, the assumption of plane strain condition of basement-tunnel interaction grossly overestimates tunnel movements, and ignores tensile strain of tunnel along its longitudinal direction. Thus, three-dimensional numerical analyses are required to obtain a reasonable estimation of tunnel responses due to adjacent and overlying basement excavations in clay.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.1087-1094
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• 2010

With recent growth of population and industry, urban development grows into grand scheme of excavation and construction in urban area. As the development progress advanced, the developments get large and deepen. With a progress of technology development in geotechnical engineering in Korea, most our grand scheme of projects follows great progress. On the other hand, some excavation in construction site caused direct or indirect event that affects the adjacent or surrounding structures by excavation from time to time. This event usually happens around residential and commercial area where underground tunnel, subway station, commercial building, and high-rises excavation site is, could lead great damage on economy as well as personal injury or human casualties. In order to prevent this event, the study has to be done with analysis on various events of excavation and its cause. In this paper, the research has collected the various excavation events and their causes to analyze on each site and event to define emphasis on surrounding environment.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.669-670
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• 2015

Efficient management of the construction heavy equipment is required to reduce the rate of carbon emissions and on-site accidents. The intelligent excavation system (IES) will improve the construction quality and productivity through information technologies and efficient equipment operation, especially in large earthwork projects. Three-dimensional digitized ground data should be required for identifying the path of heavy equipment and work-site environment. Rapid development of terrain laser scanners (TLS) is more readily to acquire the digital data. This study suggests the '3D ground terrain processing platform (3DGTPP)' including data manipulating module and analyzing module of the scanned data for intelligent earthmoving equipment operation. The processing platform consists of six modules, including scanning, registering, manipulating, analyzing, transmitting, and storing. 3D ground terrain processing platform presented in this study will provide fundamental information for intelligent excavation system (IES), which will increase the efficiency of earthworks and safety of workers in significant.