• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.1
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• pp.75-83
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• 2016

In case of underground construction affected by groundwater, CIP (Cast-In-Place Pile) method is generally used to resolve the geo-hydraulic problem. However, as this method has poor connectivity between piles, an auxiliary method for cut-off is needed in many cases. In this study, a new concept earth retaining wall method (H-CIP) with no auxiliary method, by using surfactant grout (Hi-FA) which improves antiwashout and infiltration ability, is introduced, and its field applicability is evaluated. CIP and H-CIP piles were installed with same ground conditions, and field and laboratory tests were conducted to verify the performance. As results, newly contrived H-CIP method shows higher field performance for cut-off and strength than conventional CIP method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.4
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• pp.70-77
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• 2010

Microcement grouting and micro pile are frequently used for ground modification during tunnel construction. The influence of grouting pressure of microcement grouting and micro pile to the existing bridge which is directly over the constructing tunnel is investigated. Three dimensional seepage flow-structure interactive analysis considering firm water pressure with full stages of construction including the construction of upper bridge, microcement grouting, micro pile and tunnel is performed. The settlement and tilting of the pier of existing bridge violate the design code and the reaction of the bridge are highly increased after grouting. The stress of tunnel bracings such as rockbolt and shotcrete also exceed the limit of the code. The pressure of microcement grouting is confined by bedrock and transmit to the surrounded soil and the upper bridge. Microcement grouting needs mid-high pressure to penetrate through weak fault plane and the pressure greatly influence the safety of the upper structure. It is important to decide and care the grouting pressure to improve weak fault plane directly under the existing structures and the pressure of microcement grouting should be considered in underground analysis.

• 월간 기계설비
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• no.11 s.184
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• pp.57-71
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• 2005

SHOP DWG의 현주소 어디까지 왔는가? 설계에서 제조에 이르는 전 과정을 컴퓨터로 제어하고 관리하는 기술. 캐드(CAD)와 캠(CAM)은 각각 computer-aided design,computer-aided manufacturing의 약칭으로 컴퓨터보조설계와 컴퓨터보조생산을 뜻한다. CAD는 설계도면을 한 장씩 수작업으로 제도하지 않고 설계 데이터베이스의 정보를 CRT(cathode ray tube)에서 화상을 보고 합성하면서 설계하므로 작업을 최적화 할 수 있다. CAD로 설계된 설계도의 내용은 CAM을 통해 NC(수치제어)공작기계에 정확한 작업동작을 지시하게 되며, 작업관리∙가공∙조립∙검사 등의 제조과정을 컴퓨터로 관리하여 작업속도와 제품의 정밀성을 높이게 된다. 최근에는 건축현장의 2D system이 보편화되어 있지만 건축현장의 핵심이라고 할 수 있는 기계설비의 기계실, 또는 조립화 공법 등에는 3차원 CAD∙CAM시스템이 개발되어 입체형상을 화면에 3차원으로 재현할 수 있고, 대상물의 표면적∙부피∙무게∙강도 등의 물리적 성질도 자동 계산하여 최적상태에서 현장의 시공에 적용할 수 있게 되었다. 1960년대 초 미국에서 자동차 모델∙엔진, 항공기 부품 등 의 설계에 수작업의 한계를 느껴 개발되었으며, 한국에서는 70년대 중반에 도입되어 운용되고 있다. 이에 따라 프로그램 회사들은 다양한 방법 등을 SHOP DWG에 적용하여 판매경쟁이 치열하다. (주)우진아이엔에스는 급속한 산업경제의 변화와 무한경쟁시대에 보다 나은 기술개발 투자에도 노력을 기울여, 2000년 11월 용인공장, 생산라인을 천안으로 이전, 확장 하여 배관 및 닥트의 CAD-CAM SYSTEM, P.F.P공법, 기계실3D, 블럭화배관, 닥트자동화 시스템, 설계, 용접공정을 공장화시켰으며, 신 개발품인 S.C.D(SEMI-CON DUCT)를 신설하여 모든 건축물에 맞는 필수적인 제품을 생산함으로써 선택의 폭을 넓히고, 현장 시공능력 효율을 높이고 있다. 이번 호에서는 (주)우진아이엔에스가 95년 설계팀을 발족하여 제로시스템의 3D공법을 공장 및 현장의 SHOP DWG에 적용해왔고 최근에는“서초 프로젝트A”현장에 SHOP DWG의 최대 결집체인 3D활용의 조립화 공법을 적용하여 초고층 오피스텔현장을 시공한 사례를 게재한다. 우진아이엔에스는 30여년의 기술 축척을 바탕으로 최고의 기술력과 풍부한 경험을 통해 아셈무역센타, 타워팰리스1차, 3차 및 목동트라팰리스, 분당트리폴리스, 수원삼성전자 R4, 등 국내굴지의 초고층빌딩 시공을 근거로 초고층의 기본설계를 이해하고 SHOP DWG을 통해서 기계설비공사의 향후 나아갈 지표를 제시하고 있다.

• Geotechnical Engineering
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• v.12 no.5
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• pp.5-16
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• 1996

When braced excavation with temporary retaining wall installation, is performed in loose sand with high ground water level boiling may be induced and considerable damage on the excavation works and structures in the vicinity can take place. Recently, for the purpose of reinforcement of ground and cut-off of ground water behind the temporary retaining wall, high pressure jet grouting is widely used. The purpose of this paper is to investigate the effects of jet grouting on ground reinforcement and cut -off of the ground water behind temporary retaining walls for braced excavation. A series of both laboratory and field tests has been performed. The test results show that high pressure jet grouting has sufficient effects on reinforcement of stiffness of ground and retaining wall. The permeability of the improved ground was 10-f_ 10-3cm l s smaller than those of the original ground. Therefore, the effect on cut off of ground water behind temporary retaining walls could be improved by high pressure jet grouting method.

• Tunnel and Underground Space
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• v.29 no.3
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• pp.148-156
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• 2019

In urban area, the use of mechanical excavators (e.g., TBM and roadheader) has been increasing in construction of tunnelling and underground space. The undercutting technology, which is modified from the conventional rock-cutting concept, has been developed by advanced countries. Therefore, research on the latest technology of mechanical excavation is required, and keeping carrying out research on conventional mechanical tunneling methods at the same time. In this study, as a fundamental study of the undercutting technique, the principle and concept of the undercutting were introduced, as well as the current status of the research of advanced countries. The undercutting is applicable as a full-face excavation method for the tunnels and underground spaces, as well as an auxiliary(partial-face excavation) method for extension of the existing tunnels.

• Journal of the Korean GEO-environmental Society
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• v.3 no.3
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• pp.27-36
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• 2002

Generally, it is known that urethane injection is excellent in long-term durability and environment friendly for ground improvement. However, urethane grouting has short rise time thus the penetration distance from the injection point is so short. Therefore, urethane injection cannot be used for the site where requires ground improvement in deep location from the injection point. Other injection materials such as cement cannot be alternatives when rapid hardening is required. From this study, we improve disadvantage urethane injection by developing TAS method. From the field tests, it is ascertained that TAS increases injection distance over 10m, which is further than that of original urethane grouting. In addition, TAS has relatively short Rise-time compared to cement grouting thus instantaneous improvement can be mobilized right after the injection. Short Rise-time and long penetration distance provide excellent applicability for tunnel construction.

• Journal of the Korea Institute of Building Construction
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• v.18 no.2
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• pp.99-107
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• 2018

The objective of the present study is to propose a reliable shape of supplementary V-ties in the section jacketing approach for seismic strengthening of reinforced concrete columns. A total of 24 pull-out specimens were prepared. The test parameters selected with regard to bond strength of V-ties were the shape of V-ties, embedment length of V-tie legs, and compressive strength of concrete. The measured bond strength of V-ties with different shapes were compared with that of the conventional V-ties and predictions using CEB-FIP equation. Ultimately, V-ties with pressed end-details at their legs could be recommended for the supplementary lateral reinforcement of strengthening columns with jacketing thickness less than the embedment length [= max (75mm, $6d_b$)] of conventional V-ties, where $d_b$ is the diameter of the reinforcing bar used for V-ties.

• Explosives and Blasting
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• v.21 no.3
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• pp.1-10
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• 2003

터널굴착발파공법의 하나인 V-cut발파공법은 터널굴착기술이 발전되는 과정에서 초기에 개발되어진 기술이나 작업의 간편성과 효율성으로 인하여 많은 터널굴착공사에서 이용되고 있는 발파공법이다. V-cut발파공법은 일자유면 상태에서 V형으로 심발공을 발파하고 심발공에 의해 형성된 자유면을 이용하여 확대공으로 굴착공간을 넓히는 발파 방법이며 심발발파의 굴진장에 의해 단일발파당 굴진장이 결정된다. V-cut발파법이 개발된 이래 V-cut발파의 굴진장을 증대시키기 위한 방법으로 심발발파공의 구속저항을 감소시키기 위해 보조심발공을 발파하여 형성된 자유면에 의해 심발공의 최소저항선거리를 줄여 발파하였으나 심발공의 구속저항이 감소되지 않아 발파효율이 증대되지 않았으며 발파진동 또한 가장 크게 발생하였다. 이와 같은 현상은 최소저항선거리의 감소효과에 대한 발파기술상의 이론에 문제가 있기 때문이다. 본 연구에서는 V-cut발파법의 심발공에 대한 구속저항감소효과가 발현될 수 있는 조건들을 검토하여 최소저항선거리의 감소효과가 발현될 수 있는 조건을 제시 하여 심발공의 발파효율을 증대시키고 발파진동이 적어지는 발파방법을 제안하려 한다.

• Tunnel and Underground Space
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• v.18 no.5
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• pp.355-365
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• 2008

Displacement caused by tunneling is difficult to predict since it is affected by many factors such as ground condition, excavation method and supplementary method of reinforcement. In this study, horizontal inclinometer was employed to monitor ground settlements above a tunnel face before and after the excavation. Monitoring results were analyzed to predict the preceding displacement and settlement of the surface structures. The result of the analysis can be used to establish a proper counter measure which keeps the serviceability of the surface structures. Based on the analysis of the monitoring result, ground properties of the site were deduced and the influence of the tunnel excavation on the settlement of the foundation above the tunnel is analyzed.

• Journal of the Korean GEO-environmental Society
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• v.13 no.3
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• pp.59-70
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• 2012

In this study, to select the best stabilizer for the heavy metals-contaminated soil from a smelter area during phytoremediation, a plant uptake experiment and a soil stabilization were simultaneously applied using Pteris multifida Poir. and five pre-screened stabilizers(zeolite, Mn dioxide, slag, Ca oxide, and magnetite). The extracted heavy metal was measured and compared using a 3 step sequential extraction for the soil samples. The growth rate of the plant was also evaluated. The stabilizers stabilized heavy metals in soil and reduced the extraction rate. Magnetite and calcium oxide showed better results than other stabilizers. The stabilizers enhanced the growth of the plant. All the heavy metals except for arsenic were concentrated in roots while arsenic was concentrated in leaves of the plant. It is concluded that the stabilizers can minimize the heavy metal release from the contaminated soil during phytoremediation and stimulated the growth of plant. These effects of stabilizers could compensate for some weak points of phytoremediation such as reaching of heavy metals by rainwater.