• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.11
• /
• pp.5551-5557
• /
• 2012

Sedimentary rocks dug up in construction fields are mostly stockpiled for landfill disposal, leading to an increase in construction costs and construction inefficiency. After screening, some of the sandstone can be used as aggregate; however, most of the shale ends up as industrial waste in practice. In this study, to stabilize the demand and develop resources for alternative aggregates of concrete, the potential use of shale, which is widely distributed in the Daegu-Kyeongbuk region, as a concrete aggregate was evaluated. Red and black shale exported from a Daegu excavation site was selected for use in the experiments and evaluated by comparing with hornfels, which is widely used as a coarse aggregate and is a type of andesite and metamorphosed sedimentary rock. The physical properties of the aggregate were evaluated in accordance with the test methods of KS F 2527 "crushed concrete aggregate," and the compressive strength against the shale aggregate replacement ratio was measured. The compressive strength of the concrete after 28 days was 30.8 MPa when the black shale replaced 100% of the aggregate in the concrete and 31.1 MPa when the red shale replaced 100% of the aggregate in the concrete. Compared with the compressive strength of 37.5 MPa for concrete prepared by using plain aggregate, using shale as a substitute for the aggregate produced an average compressive strength that was 82% of normal concrete.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.8
• /
• pp.4033-4038
• /
• 2013

Sedimentary rocks from construction waste are discarded through open storage and landfilling, which causes an increase in construction cost and inefficient of execution of works. Some sandstone are selected and utilized as aggregates, but shale is buried as industrial waste. Therefore, in this research, we evaluated weathering properties of shale aggregate that is widely distributed throughout Daegu-Kyeongbuk region and freeze-thaw characteristics of concrete according to the replacement ratio of shale aggregate, in an effort to stabilize aggregate supply-demand in Daegu-Kyeongbuk region and develop alternative aggregates. We used red shale and black shale in the experiment, which were exported from a construction site in Deagu. We verified the usage of shale as a concrete aggregate by comparing andesite, which is broadly used as a thick aggregate for concrete, to hornfels, which is a metamorphic sedimentary rock. As a result of the experiment, we observed no degradation phenomenon for andesite and hornfels. However, a part of country rock containing black shale was found to be exfoliated. Red shale started having cracks in the direction of stratification after 1.5 months of direct exposure, and it broke into smaller pieces after approximately 4 months. After 300 cycles of freeze-thaw process on the concrete manufactured according to the replacement ratio of shale aggregate, the modulus of elasticity was 97% for plain and 95% for hornfels. In the case of RS_100, it was 57% after 210 cycles, and for BS_100, it was 54% after 240 cycles. Therefore, we established that, as the number of repetition increases, the freeze-thaw resistance decreases dramatically.

• Journal of the Korean Geosynthetics Society
• /
• v.21 no.4
• /
• pp.41-53
• /
• 2022

In the excavation work like blasting/excavator work bordering on the urban railway, the dynamic safety of railway structures like tunnel, open-cut box structure and elevated bridge was investigated by numerical analysis in this study. The practically presented criteria on influential zones at the blasting work in the construction industry was numerically checked in cases of the precise vibration-controlled blasting (type II) and the small scale vibration-controlled blasting (type III) and it was shown that the criteria on blasting work methods needed to be supplemented through continuous field tests and numerical analyses. The influence of excavation vibration by mechanical excavators was especially investigated in case of earth auger and breaker. The numerical analysis of tunnel shows that the criteria on vibration velocities from the regression analysis of field test values was conservative. The amplification phenomenon of excavating vibration velocity was shown passing through the backfilling soil between the earth auger and the open-cut box structure. It was shown that the added-vibration on the superstructure of elevated bridge was occurred at the bottom of pile like earthquake when the excavator vibration was arriving at the pile toe. The systematic and continuous research on the vibration effect from excavating works was needed for the safety of urban railway structures and nearby facilities.

• The Journal of Engineering Geology
• /
• v.13 no.3
• /
• pp.359-368
• /
• 2003

A quarry is operated for filling-up the New Busan Harbor which is under construction, but actual rock quality is something different from the primary design. Therefore, object of this study is to classify whole rock quality for the quarry through site investigation and laboratory analyses because unexpected large amount of wasted rock is produced. For this object, various analyses were performed such as surveying, Schimidt Hammer test. joint spacing investigation and laboratory analyses using DIPS & RockWorks programs for evaluating joint sets and sizes of rock fragments after blasting. As a result, it is expected that large amount of wasted rock under ${\Phi}100mm$ is produced after blasting because of high joint density.

• 월간 기계설비
• /
• s.297
• /
• pp.94-103
• /
• 2015

삶의 터전이 부족한 자연환경을 극복하기 위해 인간은 쓸모없는 땅을 개척하고, 다리를 놓고, 둑을 막는 등 끊임없이 노력함으로써 좀더 풍요로운 삶으로 발전시켜왔다. 그 중 호수나 바닷가에 제방을 쌓고 육지를 만드는 간척은 좁은 땅덩어리를 넓힘으로써 삶의 터전을 좀더 확대시킬 수 있다. 우리나라는 삼면이 바다로 둘러싸여 있고 특히 서해안과 남해안은 리아스식 해안에 갯벌이 발달하여 간척에 유리하다. 간척은 삼국시대부터 그 흔적을 찾을 수 있고 조선시대까지는 작은 갯고랑이나 해변을 막는 정도였으나 일제 강점기 때 주로 군량미 조달 등을 목적으로 본격적인 간척이 이루어졌다. 해방 후에도 간척은 계속되었고 1980년대 이후 중장비가 등장하면서 수천 미터의 제방 길이와 거대한 물목을 틀어막는 대규모 공사로 발전하였다. 근대의 간척사업이 군량미 확보와 미곡 증산 중심이었다면 최근의 간척사업은 생태환경 복원, 관광 등 다목적 용도로 쓰임새가 변화하는 추세이다. 서해안에서는 지금 국토를 넓히는 역사적인 사업이자 최대 규모의 국책사업인 간척사업이 한창 진행 중이다. 중국 동해안을 중심으로 한국과 일본 큐슈를 잇는 환황해권이 세계 최대 경제로 떠오를 것으로 예상됨에 따라 정부가 환황해권의 주도권을 잡기 위해 새만금개발사업을 적극 추진하고 있다. 세계 최장 33km의 방조제와 $401km^2$의 땅을 매립하여 농업 산업단지, 복합도시, 21세기 동북아 관광레저의 허브 등 다용도로 활용하기 위함이다. 본지는 바닷내음 물씬 풍기는 광활한 새만금 벌판에서 새만금집단에너지시설 건설공사를 시공 중인 (주)정호이앤씨(대표 최호선) 양석동 현장소장과 원도급 업체인 두산중공업 용환윤 소장을 만났다.

• Journal of Korean Society for Geospatial Information Science
• /
• v.5 no.2 s.10
• /
• pp.169-177
• /
• 1997

The purpose of this paper is to study the ideal Auto-surveying system and to establish the standard of work procedure involved with completing a precise three-dimensional topographic survey with RTK GPS equipment, a pen based personal computer, and real time CADD software. The fieldwork was done at a golf course which could be regarded as a heavy civil project site such as the reclamation and the site preparation work in December of 1997. The proposed Auto-surveying system and the work procedure in this paper is based on the data processing and the resultant topographic map of the golf course.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.21 no.3
• /
• pp.363-375
• /
• 2019

Since the double-deck tunnel is deeply constructed in the city, it is necessary to secure the installation space of air supply and exhaust, escape passage stairs, elevator, distribution facilities and connection tunnels in the vertical shaft for the double-deck tunnel. Also, in order to minimize the effect of construction on adjacent area, it is necessary to construct the concrete structures at high speed in vertical shaft after tunnel excavation. Therefore, the slabs and the stairs in vertical shaft are needed to be constructed using precast concrete, and the rapid construction techniques of bracket for supporting the inner precast structure are needed. The bracket installation methods include cast-in-place concrete, precast concrete and steel. In this study, the improvement of the steel brackets with good economical efficiency and good workability was carried out in consideration of the improvement of the construction speed. We have developed a new bracket that is optimized through bracket shape improvement, anchor bolt position adjustment and quantity optimization. As a result of the structural performance test, it was confirmed that the required load supporting capacity was secured. As a result of structural performance test for bar type anchor bolt and bent anchor anchor bolt, it was confirmed that the required load carrying capacity was secured and that the load bearing capacity of bent anchor bolt was large.

• Journal of the Korean Geotechnical Society
• /
• v.39 no.10
• /
• pp.5-18
• /
• 2023

The construction timeline for earthworks can be significantly reduced by substituting the conventional layer-by-layer compaction using a vibratory roller with single-layer compaction through the rapid impact compaction (RIC) method. Dynamic load compaction is well-suited for coarse-grained soils like sand. However, as the supply of sand, the primary reclamation material, becomes scarcer, the utilization of soil with fines is on the rise. To implement the dynamic load compaction, such as RIC, with reclaimed materials containing fines, it's imperative to determine the effective improvement depth. In this study, we assess the impact of the RIC method on the effective improvement depth for clean sand and public fill with fines, comparing field test results before and after RIC application. Our focus is on the cone resistance (q_c) as it pertains to compaction quality control criteria. In conclusion, it becomes evident that standardizing the cone resistance is vital for the quality control of various reclaimed soils with fines. We have evaluated the compaction quality control criteria corresponding to a relative density (Dr) of 70% for clean sand as Q_tn,cs = 110. As a result of this analysis, we propose new quality control criteria for q_c, taking into account the fines content of reclaimed soils, which can be applied to RIC quality control.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2007.11a
• /
• pp.197-204
• /
• 2007

Nowadays, the construction industry is suffering from the decrease of labor productivity caused by the lack of skilled workers and the aging labor forces. The hazardous work conditions and safety problems still exist at the construction sites. The earthwork operation is not the exception. The number of skilled earthwork equipment operators has been rapidly reduced and the equipment needs to be operated in dangerous / hazardous work sites. Thus, through the development of intelligent excavating system, Intelligent Excavating System(I.E.S) research team tries to enhance the safety of work environment, productivity, quality, and payability of the earthwork operation. It is also expected that this research contributes to the development of fundamental construction automation technologies and to the creation a new market sector.

• Journal of the KSME
• /
• v.34 no.8
• /
• pp.605-616
• /
• 1994

환경산업에 대한 관심이 고조되는 가운데 국내 환경산업의 실태는 어떠한가\ulcorner 60년대 중반 태동 하여 70년대 후반 몇 백개 업체가 형성되면서 비로소 환경산업이라고 불리우기 시작했다. 그후 지속적인 성장을 이룩하면서 80년부터 92년까지 연평균 증가율 13.8%를 보이며 92년 말 등록된 방지시설업체 수는 총 7백27개업체가 되었다. 한 업체당 연간 평균 공사금액 또는 91년에 비해 92년에는 약 3억 원 정도 늘어난 것으로 나타났다. 그러나 물가상승 등을 고려해볼 때 오히려 업체들의 경영상태는 악화되었으며 영세함을 벗어나지 못하고 있다고 할 수 있다. 기술적인 측면을 살펴보면, 92년 국립환경 연구원 등 전문기관에서 평가한 국내환경기준은 선진기술을 10 0으로 기준하였을 ㄸ 폐기물 소각기술은 20-30%, 대기, 수질오염 방지기술은 60-80% 정도인 것으로 나타났다. 즉, 폐기물소각기술은 선진국에 비해 다른 분야보다 훨씬 더 낙후되어 있는 것이다. 국내 폐기물 처리가 거의 매립에 의존하고 있는 것을 보아도 미루어 짐작할 수 있다.