• 기술발표회
• /
• 통권2006호
• /
• pp.135-145
• /
• 2006

Soil nailing systems are generally many used in underground excavations and reinforcements of slopes since the first construction as a temporary retaining wall in 1993, Korea. In recently, they are many attempts to expand the permanent reinforcements of slopes However, experimental studies related to soil nailing systems are insufficient Specially, there are no researches related in the large scaled load tests of soil nailed walls in Korea In this study, a case study on the large scaled load tests of soil nailed walls is introduced and the behavior characteristic of them is investigated Also, they are proposed allowable deformation corresponding to the serviceability limit of soil nail walls and ultimate deformation corresponding to the collapse state of the walls. These results can be applied to the maintenance management of soil nailed walls And analysis on the required minimum factor of safety of soil nailed walls using the relation curve of load ratio and deformation ratio are carried out

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2005년도 동계학술발표대회 논문집
• /
• pp.141-147
• /
• 2005

Although the importance of good conservation of historic sites including ancient royal tombs is wet] aware, still not much attention has been paid for the facilities and systems to preserve those historic sites, which includes precious artifacts as wall paints and carved works, etc. Even the general understanding about the environment of the underground space of tombs is not satisfactory. In the present study, vibration levels due to the operation of an HVAC system to maintain the desired indoor temperature and humidity are investigated experimentally. According to the measured data, the level of vibration inside the present model tomb with the indoor unit inside, showed order of magnitude less values than the Swiss Standards, but still higher than the value suggested by German standards, which is, zero. For the vibration level depends not only on the system design, but also on the installation methods, further study will be pursued for cases including different ways of installation.

• 국제초고층학회논문집
• /
• 제9권3호
• /
• pp.283-300
• /
• 2020

The Lakhta Center is a Multifunction Complex Development (MFCD) consisting of 1) an 86 story office tower rising 462 m above the ground to provide high-end offices for Gazprom Neft and Gazprom Group affiliates 2) a Multi-Function Building (MFB) that includes, a scientific/educational center, a sport center, a children's technopark, a planetarium, a multi-transformable hall, an exhibition center, shops, restaurants, and other public facilities 3) a Stylobate 4) "The Arch, which forms the main entrance to the tower, restaurants, and cafes 5) underground parking and 6) a wide range of large public plazas. While each of the MFCD buildings is technically challenging in its own right, the focus of the paper is to present the development and integration of the structural and foundation systems of the bowed, tapered, and twisted shape of the tower into the fabric of the tallest Tower in Europe.

• Environmental Engineering Research
• /
• 제18권1호
• /
• pp.37-43
• /
• 2013

Water distribution pipes installed underground have potential risks of pipe failure and burst. After years of use, pipe walls tend to be corroded due to aggressive soil environments where they are located. The present study aims to assess the degree of external corrosion of a distribution pipe network. In situ data obtained through test pit excavation and direct sampling are carefully collated and assessed. A statistical approach is useful to predict severity of pipe corrosion at present and in future. First, criteria functions defined by discriminant function analysis are formulated to judge whether the pipes are seriously corroded. Data utilized in the analyses are those related to soil property, i.e., soil resistivity, pH, water content, and chloride ion. Secondly, corrosion factors that significantly affect pipe wall pitting (vertical) and spread (horizontal) on the pipe surface are identified with a view to quantifying a degree of the pipe corrosion. Finally, a most reliable model represented in the form of a multiple regression equation is developed for this purpose. From these analyses, it can be concluded that our proposed model is effective to predict the severity and rate of pipe corrosion utilizing selected factors that reflect the fuzzy soil environment.

• Geomechanics and Engineering
• /
• 제9권6호
• /
• pp.689-707
• /
• 2015

Progressive increase in population causing land scarcity, which is forcing construction industry to build multistory buildings having underground basements. Normally, basements are constructed for parking facility. This research work evaluates important factors which have caused the collapse of pile-anchor system at under construction five star hotel. 21 m deep excavation is carried out, to have five basements, after installation of 600 mm diameter cast in-situ contiguous concrete piles at plot periphery. To retain piles and backfill, soil anchors are installed as pit excavation is proceeded. Before collapse, anchors are designed by federal highway administration procedure and four anchor rows are installed with three strands per anchor in first row and four in remaining. However, after collapse, system is modeled and analyzed in plaxis using mohr-coulomb method. It is investigated that in-appropriate evaluation of soil properties, additional surcharge loads, lesser number of strands per anchor, shorter grouted body length and shorter pile embedment depth caused large deformations to occur which governed the collapse of east side pile wall. To resume work, old anchors are assumed to be standing at one factor of safety and then system is analyzed using finite element approach. Finally, it is concluded to use four strands per anchor in first new row and five strands in remaining three with increase in grouted and un-grouted body lengths.

• Earthquakes and Structures
• /
• 제24권1호
• /
• pp.65-79
• /
• 2023

A simplified analytical solution for seismic response of tunnel cross section in horizontally layered ground subjected to oblique incidence of SH wave is deduced in this paper. The proposed analytical solution consists of two main steps: free-field response in layered field and tunnel response. The free field responses of the layered ground are obtained by one-dimensional finite element method in time domain. The tunnel lining is treated as a thick-wall cylinder to calculate the tunnel response, which subject to free field stress. The analytical solutions are verified by comparing with the dynamic numerical results of two-dimensional ground-lining interaction analysis under earthquake in some common situations, which have a good agreement. Then, the appropriate range of the proposed analytical solution is analyzed, considering the height of the layered ground, the wavelength and incident angle of SH wave. Finally, by using the analytical solutions, the effects of the ground material, burial depth of the tunnel, and lining thickness and the slippage effect at the ground-lining interface on the seismic response of tunnels are investigated. The proposed solution could serve as a useful tool for seismic analysis and design of tunnels in layered ground.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2022년도 가을 학술논문 발표대회
• /
• pp.145-146
• /
• 2022

The demand for a construction method capable of securing a safety environment and improving quality is increasing. There is a high risk of falling when working at a high place in an environment where it is difficult to secure visibility, such as an underground space, and there is a risk of falling if cement liquid waterproof materials are transferred to the top of the scaffold by manpower. In addition, when working on a high place in a poor environment, the quality uniformity of the upper part of the wall is deteriorated. In addition, as waterproof technicians gradually age and decrease, it is difficult to secure them, so it is urgent to prepare countermeasures against the shortage of waterproof technicians. Therefore, the purpose of this study is to develop cement liquid waterproof spouting construction equipment that can secure uniform quality of construction areas to prevent accidents and ensure safety of workers, improve work efficiency and quality due to improvement of work environment. The adhesion performance of the cement liquid waterproof material could be improved by about 20% in accordance with the use of the equipment.

• 터널과지하공간
• /
• 제17권5호
• /
• pp.389-410
• /
• 2007

불연속면의 빈도가 높지 않은 견고한 암반의 경우 굴착시 공동 주변 영역에서의 파괴나 변형 특성은 형성되어 있는 초기응력 조건과 강도 특성에 절대적인 영향을 받는다. 과도한 초기응력장은 굴착 공동 주변에 점진적이고 국부적인 취성파괴를 유발시킴으로서 시공의 안정성과 경제성을 확보하는데 장애요인으로 작용할 수 있다. 이 논문에서는 응력 수준과 터널형상에 따른 공동 주변의 취성파괴 거동 특성을 파악하기 위해 축소된 터널 시험체를 이용한 이축압축시험과 입자 결합모델을 이용한 개별요소법의 일종인 $PFC^{2D}$ 해석에 의한 연구를 수행하였다. 실내 이축압축시험을 통해 취성파괴의 발생 영역과 형태 면에서 실제 암반 공동 주변에서 발생된 파괴 특성과 유사한 파괴 거동을 모사할 수 있었다. 모형시험체에 대한 이축압축시험 결과 최소 주응력 방향의 공동 단면 곡선부에서는 균열이 표면에서 개시된 후 내부로 진행되어 국부적인 노치형 파괴영역이 형성되었다. 이에 비해 모서리와 직선부의 경우 공벽 표면과 내부에서 발생된 균열들의 상호 연결, 결합에 의해 대규모의 노치형 분리면이 유도되고 곡선부에 비해 큰 파괴영역이 형성되는 것으로 조사되었다.

• 한국건축시공학회지
• /
• 제9권6호
• /
• pp.161-168
• /
• 2009

건축공사에서 지하공사는 주공정으로 전체공기와 공사비에서 큰 부분을 차지하고 있으며, 특히 도심지의 경우 해마다 규모가 증가하고 있다. 현재 현장에서 시공하는 지하옹벽은 많은 기능 인력이 필요하고, 공사기간 측면에서도 불리한 유로폼+솔져시스템에 의하여 공사가 진행되고 있다. 따라서 본 연구에서는 토목공사 현장에서 일부 사용되고 있는 무지주 거푸집을 기초로하여 건축공사에 적용 가능한 무지주 거푸집을 개발하였다. 또한 거푸집의 크기를 가정하여 건축공사 현장에서 가장 많이 사용되는 유로폼+솔져시스템과 경제성 측면에서 비교.분석하였다. 연구 결과, 합성 무지주 거푸집은 유로폼+솔져시스템에 비해 공사비가 약 9%높게 나타났으며, 비합성 무지주 거푸집은 약 9%낮게 나타났다. 하지만 합성 무지주 거푸집의 경우 구조체공사에서 콘크리트와 철근의 물량이 현저히 감소하여, 기존옹벽 시공가격 보다 약 35% 경제적 원가절감 효과를 볼 수 있다.

• 한국터널지하공간학회 논문집
• /
• 제4권3호
• /
• pp.175-184
• /
• 2002

일반적으로 터널 굴착시 지보재의 설치시기에 대한 예측을 위하여서는 지반반응곡선 (Ground reaction curve)을 활용하고 있다. 이 지반반응곡선은 굴착에 따른 지반의 변위 특성을 나타내며, 일반적으로 원형단면이고 등방상태 (K = 1.0)로 가정하여 단순화시킨 Closed Form Solution을 통해서 구해진다. 그러나, 원형단면이 아니고, 비등방 응력상태인 실질적인 현장조건을 고려해 본다면, 이 지반반응특성 예측식을 현장조건에 적용함에 있어서 어떠한 한계점을 갖는지에 대하여 규명할 필요가 있다. 이를 위해, 본 논문에서는 굴착단면 형상에 따른 측벽에서의 초기탄성변위 및 임계지보압의 변화 특성에 대하여 연구하였다. 터널굴착 형상은 단면의 높이 (b)와 폭 (a)의 비, 즉 굴착형상 계수 S (=b/a)값이 1.0, 0.8, 0.6, 0.4로 변화하도록 하였으며, 각각의 굴착형상마다 초기등방응력을 5~30 MPa사이에서 변화시켜가면서 수치해석을 통해 지반반응곡선을 얻었다. 수치해석을 통해 얻어진 측벽에서의 지반반응곡선을 분석하여 그에 따른 특성을 제시하였다. 검토결과 지반의 자립성을 평가하는데 있어서 Closed form solution의 사용에는 한계가 있는 것으로 판단된다.