• Journal of the Korean Geotechnical Society
• /
• v.16 no.5
• /
• pp.117-127
• /
• 2000

터널 시공과 굴착과정에서 파쇄대, 절리, 연약대, 균열 등 암반에서의 불연속면은 중요한 역할을 한다. 본 연구에서는 지반 고유의 특징인 불확실성에 의한 터널 설계와 시공 과정에서 겪는 많은 시행오차를 최소화하기 위해서 국내의 터널 붕락 현장의 지반조사 자료를 분석하여 터널 붕락 유형 및 규모를 제시할수 있는 Geo-predict 시스템을 개발하였다. Geo-predict 시스템은 총 104개 터널 붕괴/붕락자료(국외84개, 국내20개)를 분석한 자료를 테이터베이스로 인공신경망 학습을 토해서 터널 붕괴 형태와 규모를 추론하는 시스템이다. 본 논문에서는 Geo-predict의 개발과정 및 구성.기능을 소개하였으며 104개 터널 현장 자료를 지반조건별로 분석하고 이를 데이터베이스화하여 인공신경함을 이용한 추론 시스탬을 구축하고, 2개 고속전철 터널현장과 1개 지하철 시공현장에 적용성 평가를 실시하여, 터널의 붕락 가능 및 붕락 규모를 추론하였다.

• Journal of the Korea Institute of Building Construction
• /
• v.15 no.5
• /
• pp.527-536
• /
• 2015

This research focuses on comparing the impact that working conditions have on the job satisfaction of Korean and Chinese-Korean construction workers. The data shows that factors such as the quality of wages, food catering, and leisure facilities showed a positive correlation on the workers' satisfaction. Further comparative analysis showed differences between the effect these factors have on the satisfaction of Korean workers and Chinese-Korean workers, who occupy the highest portion of the foreign workforce in Korea. The analysis concluded that to the Chinese-Korean workers, wage had the strongest impact on their satisfaction over other factors, whereas this difference was not present in the Korean workers. The results of this study highlighting these differences between the worker groups can contribute to developing the efficiency of the management of construction sites in Korea.

• Journal of the Korea Institute of Building Construction
• /
• v.17 no.1
• /
• pp.91-100
• /
• 2017

The safety management is one of important factors. However, the satisfaction of safety manager is lowering. Therefore, this study focuses on comparing the impact that working conditions have on the job satisfaction of field and safety manager in construction field. The results of in this study, the basic wage, medical care, and leisure activity were analyzed as a positive impact on job satisfaction. In addition, the comparison result of the field manager and safety manager showed that safety manager appeared to be a greater impact on the basic wage than the field manager. Also, this study showed that the medical care and leisure activity have a positive impact on the job satisfaction of field manager, but the industrial accident and accommodation facility have a positive impact on the job satisfaction of safety manager.

• Journal of the Korea Institute of Building Construction
• /
• v.18 no.6
• /
• pp.517-525
• /
• 2018

The construction of super tall building which structure is RC and must be certainly considered on column shortening estimation and construction reflected concrete creep has been increased. Regarding the Fck 60~80MPa grade high strength concrete applied in the domestic super tall building project, the mechanical properties and creep deflection according to curing conditions(Drying creep/Basic creep) were reviewed in this research. Results of compressive strength and elastic modulus under sealed curing condition were 5% higher than unsealed condition and difference of results according to the curing condition was increased over time. Autogenous and drying shrinkage tendency showed adversely in the case of high strength concrete. Additionally, creep modulus under unseal curing condition was evaluated 2~3 times higher than sealed condition. Modified model of ACI-209 based on test result was applied to estimate long period shortening of vertical members(such as Core Wall/Mega Column) exactly, it is designed to modify and suggest the optimal creep model based on various data accumulated during construction, in the future.

• Journal of the Korea Institute of Building Construction
• /
• v.18 no.6
• /
• pp.527-532
• /
• 2018

The objective of the present study is to evaluate a practical approach for enhancing the compressive strength and minimizing deforming of aerated concrete. Test results measured in the aerated concrete mixes that were produced using 40% ground granulated blast-furnace slag (GGBS) as a replacement of cement and cured under different conditions (i.e., high temperatures of $40^{\circ}C$ and $60^{\circ}C$ for 10 hrs or 15 hrs) were compared with those obtained from the specimens cured under room temperature. No deforming was observed in the mixes with 40% GGBS. The compressive strength of the prepared aerated concrete cured under high temperature was higher than that of the concrete cured at room temperature, even at the lower ranges of the apparent dry density. However, the curing time is needed to be controlled as not exceeding 10 hrs at the temperature of $60^{\circ}C$ to prevent the decrease in the compressive strength due to foam mergences.

• Journal of the Korean Geotechnical Society
• /
• v.23 no.7
• /
• pp.99-104
• /
• 2007

The deep soil mixing, on ground modification technique, has been used for many diverse applications including building and bridge foundations, port and harbor foundations, retaining structures, liquefaction mitigation, temporary support of excavation and water control. This method has the basic objective of finding the most efficient and economical method for mixing cement with soil to secure settlements through improvement of stability on soft ground. In this research, the experiments were conducted on a laboratory scale with the various test conditions of mixing method; the angle of mixing wing, mixing speed. Strength and shapes of improved soil of these test conditions of deep mixing method were analysed. From the study, it was found that the mixing conditions affect remarkably to the strength and shapes of improved soils.

• Proceedings of the KSR Conference
• /
• 2005.05a
• /
• pp.646-654
• /
• 2005

The crossing construction under railroad have two methods which are cut and cover and trenchless method. First, cut and cover method is an extremely limited method concerning non-running time. Whereas, trenchless method is free from restriction such as train speed and running time, and has the strong points of safe and rapid construction. Front Jacking method, one of the trenchless methods, is frequently applied recently due to its stability during construction and vantage of assuring schedule reliability. The procedure is that after minimizing interlocking friction with structure and earth pressure due to jacking the small steel tube, pulling the precast box manufactured at the field in the ground using PC strand and hydraulic Jack. This method is able to be applied regardless of section size and length of box and condition of soil. And that is also pro-environmental. This paper presents the case of Daejeon E. W. perforate Road Project applied with the Front Jacking method.

• Tunnel and Underground Space
• /
• v.28 no.1
• /
• pp.1-24
• /
• 2018

The use of TBM (tunnel boring machine) gradually increases in worldwide tunneling projects. TBM machine are often applied to more difficult and complex geological conditions in urban area, and many problems and difficulties have been reported due to these geological conditions. However, in Korea, there is a lack of research on difficult grounds so far. This paper discussed general aspects of investigation method, and problems of TBM tunneling in difficult grounds. Construction cases that passed through the difficult grounds in worldwide were analyzed and the typical difficult grounds were classified into 11 cases. For each case, the definition and general problems were summarized. Particularly, for mixed ground and boulder ground, and fault zone, which are frequent geological conditions in urban area with shallow depth, classification system, investigation methods and major considerations were discussed, and proposed the direction of future research. This paper is a basic study for the development of TBM construction technology in difficult ground, and it is expected that it will be useful for related research and construction of TBM in difficult ground in the future.

• Journal of the Korea Institute of Building Construction
• /
• v.10 no.1
• /
• pp.181-191
• /
• 2010

Lightweight panels are currently used in many ways, such as inner walls of the skyscrapers and residential buildings in Korea. Moreover there has been an increasing of interest in developing construction method and quality improvement as many buildings became higher, because there are more advantages like constructability, finishability, and economic efficiency, etc. than previous heavy weight concrete wall. It is necessary to analyze the characteristics and evaluate the performance of lightweight panels when selecting proper methods and materials to building characteristics and builder's demand. However, there doesn't exist systematic data with a classification of lightweight panels' type and performance. The purpose of this study is to classify domestic lightweight panels by both type of exterior board and construction method, and also to evaluate each performance by surveying user's opinion.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.30 no.4
• /
• pp.343-350
• /
• 2017

The RC flat plate system has benefits such as a short construction time, an improvement of workability and a floor height reduction. In the case of long span slab, cracking damages and large deflections tend to occur due to the low flexural stiffness of flat plates. Specially, over-loading by self-weight of slab during construction increases short and long-term deflections. These problems may be solved by the use of void slab that has benefits of the reduced self-weight. In this study, to analyze an effect of self-weight reduction of void slab on slab deflections, the parametric study is performed. Including variable conditions such as a concrete strength, a slab construction cycle, the number of shored floors, a compressive reinforcement ratio and a tensile reinforcement ratio, slab construction loads and deflections are calculated by considering the construction stages, concrete cracking, and long-term effects. The short-term deflections during construction and the long-term deflections after construction of both of normal and void slabs are compared and the effects of void slab on the reduction of slab deflections are analyzed.