• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.4
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• pp.459-468
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• 2023

Power plant is a kind of basic industrial facility and might cause fatal industrial and human damage. In this study, the characteristics and effect of blast-induced vibration for tunnelling which underpass ○○ power plant in operation were evaluated. Previous blasting cases adjacent to industrial facilities were intensively reviewed, then allowable vibration criteria were suggested. 3 dimensional dynamic numerical analysis based on finite element method was performed to investigate particle velocity and resonance was examined by calculating the predominant frequencies. As a result, particle velocity at pump foundation which is nearest to the source was approached to the allowable criteria, therefore, the modified blasting pattern was newly suggested and confirmed the attenuation effect based on the test blasting. Consequently, appropriated decision-support procedure was established in case of adjacent blasting to industrial facilities.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.302-302
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• 2021

지하차도의 경우 국지 및 돌발홍수가 발생할 경우 대부분 침수됨에도 불구하고 2020년 7월 23일 부산 지역에 밤사이 시간당 80mm가 넘는 폭우가 발생하면서 순식간에 지하차도 천장까지 물이 차면서 선제적인 차량 통제가 우선적으로 수행되지 못하여 미처 대피하지 못한 3명의 운전자 인명사고가 발생하였다. 수재해를 비롯한 재난 관리를 빠르게 수행하기 위해서는 기존의 정부 및 관주도 중심의 단방향의 재난 대응에서 벗어나 정형 데이터와 비정형 데이터를 총칭하는 빅데이터의 통합적 수집 및 분석을 수행이 필요하다. 본 연구에서는 부산지역의 지하차도와 인접한 지하터널 CCTV 자료(센서)를 통한 재난 발생 시 인명피해를 최소화 정보 제공을 위한 Object Detection(객체 탐지)연구를 수행하였다. 지하터널 침수가 발생한 부산지역의 CCTV 영상을 사용하였으며, 영상편집에 사용되는 CCTV 자료의 음성자료를 제거하는 인코딩을 통하여 불러오는 영상파일 용량파일 감소 효과를 볼 수 있었다. 지하차도에 진입하는 물체를 탐지하는 방법으로 YOLO(You Only Look Once)를 사용하였으며, YOLO는 가장 빠른 객체 탐지 알고리즘 중 하나이며 최신 GPU에서 초당 170프레임의 속도로 실행될 수 있는 YOLOv3 방법을 적용하였으며, 분류작업에서 보다 높은 Classification을 가지는 Darknet-53을 적용하였다. YOLOv3 방법은 기존 객체탐지 모델 보다 좀 더 빠르고 정확한 물체 탐지가 가능하며 또한 모델의 크기를 변경하기만 하면 다시 학습시키지 않아도 속도와 정확도를 쉽게 변경가능한 장점이 있다. CCTV에서 오전(일반), 오후(침수발생) 시점을 나눈 후 Car, Bus, Truck, 사람을 분류하는 YOLO 알고리즘을 적용하여 지하터널 인근 Object Detection을 실제 수행 하였으며, CCTV자료를 이용하여 실제 물체 탐지의 정확도가 높은 것을 확인하였다.

• Geomechanics and Engineering
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• v.35 no.4
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• pp.395-409
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• 2023

Long-span suspension bridges have tunnel anchor systems to maintain stable cables. More investigations are required to determine how closely tunnel excavation beneath the tunnel anchor impacts the stability of the tunnel anchor. In order to investigate the impact of the adjacent tunnel's excavation on the stability of the tunnel anchor, a large-span suspension bridge tunnel anchor is utilised as an example in a three-dimensional numerical simulation approach. In order to explore the deformation control mechanism, orthogonal tests are employed to pinpoint the major impacting elements. The construction of an advanced pipe shed, strengthening the primary support. Moreover, according to the findings the grouting reinforcement of the surrounding rock, have a significant control effect on the settlement of the tunnel vault and plug body. However, reducing the lag distance of the secondary lining does not have such big influence. The greatest way to control tunnel vault settling is to use the grout reinforcement, which increases the bearing capacity and strength of the surrounding rock. This greatly minimizes the size of the tunnel excavation disturbance area. Advanced pipe shed can not only increase the surrounding rock's bearing capacity at the pipe shed, but can also prevent the tunnel vault from connecting with the disturbance area at the bottom of the anchorage tunnel, reduce the range of shear failure area outside the anchorage tunnel, and have the best impact on the plug body's settlement control.

• Korean Journal of Environment and Ecology
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• v.20 no.3
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• pp.340-344
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• 2006

The objective of this paper was to investigate the potential of road-crossing structures as biological corridors that can overcome wildlife habitat fragmentation caused by road construction. Snow tracking on animal trace adjacent to and under bridges, underpasses, and culverts of eight rural highways in Korea was carried out. A total 89 structures were monitored and the results follow. First, the probability of road crossing increases with the increasing cross sectional size of crossing structures. Second, small to medium sized carnivores such as raccoon dog, leopard cat, and Siberian weasel use all types of structures. Finally, water deer, or large herbivore crossed only under bridges. Consequently, further studies are necessary to identify suitable types of road crossing structures that can mitigate the probability of road-kills and habitat fragmentation of water deer.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.2
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• pp.133-139
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• 2018

Keeping a proper straight route length under the marine bridge is one of the important factors for the safe passage of ships. However, according to port and harbor design standards, there is only a constant guideline of 8 times the length of the marine bridge underpass. On this study, we used the ES model to determine the ratio of risk to the route width, traffic volume, the degree of curvature of the route, and the length of the straight route in order to derive the optimal straight route distance. As a result, the risk ratio decreased by 2.27% as the route distance increased from 3L to 10L when the degree of curvature of the route was $45^{\circ}$. The risk associated with curvature was found to be 4.83% when the bending degree was changed from $0^{\circ}$ to $45^{\circ}$ in the case of 3L length. In addition, it was confirmed that the risk ratio according to the degree of curvature of the route and the straight route was reduced by 1.45% at maximum under the condition that the width of the line was 400m and the number of the vessels generated per hour was 20. It was verified that a straight route distance more than a certain length is needed depending on the congestion degree and the degree of curvature of the route when constructing the marine bridge.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.4
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• pp.1-7
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• 1999

We developed Fabrication process of embedded passive components in MCM-D substrate. The proposed MCM-D substrate is based on Cu/photosensitive BCB multilayer. The substrate used is Si wafer and Ti/cu metallization is used to form the interconnect layer. Interconnect layers are formed with 1000$\AA$ Ti/3000$\AA$ Cu by sputtering method and 3$\mu\textrm{m}$ Cu by electrical plating method. In order to form the vias in photosensitive BCB layer, the process of BCB and plasma etch using $C_2F_6$ gas were evaluated. The MCM-D substrate is composed of 5 dielectric layers and 4 interconnect layers. Embedded resistors are made with NiCr and implemented on the $2^{nd}$ dielectric layer. The sheet resistance of NiCr is controlled to be about 21 $\Omega$/sq at the thickness of 600$\AA$. The multi-turn sprial inductors are designed in coplanar fashion on the $4^{th}$ interconnect layer with an underpass from the center to outside using the lower $3^{rd}$ interconnect layer. Capacitors are designed and realized between $1^{st}$ interconnect layer and $2^{nd}$ interconnect layer. An important issue in capacitor is the accurate determination of the dielectric thickness. We use the 900$\AA$ thickness of PECVD silicon nitride film as dielectric. Capacitance per unit area is about 88nF/$\textrm {cm}^2$at the thickness of 900$\AA$. The advantage of this integration process is the compatibility with the conventional semiconductor process due to low temperature PECVD silicon nitride process and thermal evaporation NiCr process.

• Journal of the Society of Disaster Information
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• v.16 no.4
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• pp.734-746
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• 2020

Purpose: Increase in the size and number of underpasses rises occurrence of disasters such as fire and flooding inundation in underpasses. In the occurrence of disasters, the underpasses are more vulnerable to expose of crucial disasters than the general roads due to they are built underground. Therefore, The purpose of this paper is to derive system improvement items to prevent and control disasters in underpasses. Method: A hierarchical model of disaster impact factors and alternatives was developed based on prior researches and expert advices on disaster analyses and impact factors in the underpasses. The developed model was employed for surveys of pairwise comparison, and rankings of improvement were determined by applying the AHP method. Result: With a consistency of the surveys, results of relative weights of evaluation criteria(traffic accidents, fire, flooding inundation) and alternatives(law, system/planning, maintenance/human factor/environment) shows that improvement of laws and system related to the fire disaster is a top priority to prevent and control disaster of the underpasses. Conclusion: From experts' point of view, strengthening laws and systems related to disater prevention facilities such as water spray facilities, external(ground) exit in relation to fire in underpasses showed that it is an alternative to prevent disasters and minimize damage to underpasses.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.6
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• pp.429-435
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• 2021

The integrated underground space map shows the underground facility(water supply, sewage, gas, electric power, communication, heating), underground structures (subway, underpass, underground walkway, underground parking lot, underground shopping mall, common ward), ground(drilling, coffin, geology) refers to a map constructed so that a total of 15 types of underground information can be checked at a glance on a three-dimensional basis. The purpose of this study is to develop a technology to correct the problem of curved surface processing and the unevenness of underground facility pipelines that occur in converting 2D underground facility data into 3D-based underground space integrated map(3D underground facility model). do it with. To this end, we first investigated and reviewed the domestic and foreign status of technologies that generate data on underground facilities based on three dimensions, and developed a surface correction algorithm and an unevenness correction algorithm to solve practical problems. Algorithms to verify the developed algorithm This applied correction program was developed. Based on the above process, the three-dimensional model of the underground facility could be produced identically to reality. This study is judged to have significance as a basic study to improve the utilization of the underground spatial integration map.

• Geomechanics and Engineering
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• v.35 no.1
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• pp.29-39
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• 2023

As the intensity of urban underground space development increases, more and more tunnels are planned and constructed, and sometimes it is inevitable to encounter situations where tunnels have to underpass the river embankments. Most previous studies involved tunnels passing river embankments perpendicularly or with large intersection angle. In this study, a project case where two EPB shield tunnels with 8.82 m diameter run parallelly underneath a river embankment was reported. The parallel length is 380 m and tunnel were mainly buried in the moderate / slightly weathered clastic rock layer. The field monitoring result was presented and discussed. Three-dimensional back-analysis were then carried out to gain a better understanding the interaction mechanisms between shield tunnel and embankment and further to predict the ultimate settlement of embankment due to twin-tunnel excavation. Parametrical studies considering effect of tunnel face pressure, tail grouting pressure and volume loss were also conducted. The measured embankment settlement after the single tunnel excavation was 4.53 mm ~ 7.43 mm. Neither new crack on the pavement or cavity under the roadbed was observed. It is found that the more degree of weathering of the rock around the tunnel, the greater the embankment settlement and wider the settlement trough. Besides, the latter tunnel excavation might cause larger deformation than the former tunnel excavation if the mobilized plastic zone overlapped. With given geometry and stratigraphic condition in this study, the safety or serviceability of the river embankment would hardly be affected since the ultimate settlement of the embankment after the twin-tunnel excavation is within the allowable limit. Reasonable tunnel face pressure and tail grouting pressure can to some extent suppress the settlement of the embankment. The recommended tunnel face pressure and tail grouting pressure are 300 kPa and 550 kPa in this study, respectively. However, the volume loss plays the crucial role in the tunnel-embankment interaction. Controlling and compensating the tunneling induced volume loss is the most effective measure for river embankment protection. Additionally, reinforcing the embankment with cement mixing pile in advance is an alternative option in case the predicted settlement exceeds allowable limit.

• Journal of Navigation and Port Research
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• v.26 no.3
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• pp.323-328
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• 2002

Soil-steel structures have been used for the underpass, or drainage systems in the road embankment. This type of structures sustain external load using the correlations with the steel wall and engineered backfill materials. Buried flexible conduits made of corrugated steel plates for the coastal road was tested under vehicle loading to investigate the effects of live load. Testing conduits was a circular structure with a diameter of 6.25m. Live-load tests were conducted on two sections, one of which an attempt was made to reinforce the soil cover with the two layers of geo-gird. Hoop fiber strains of corrugated plate, normal earth pressures exerted outside the structure, and deformations of structure were instrumented during the tests. This paper describes the measured static and dynamic load responses of structure. Wall thrust by vehicle loads increased mainly at the crown and shoulder part of the conduit. However additional bending moment by vehicle loads was neglectable. The effectiveness of geogrid-reinforced soil cover on reducing hoop thrust is also discussed based on the measurements in two sections of the structure. The maximum thrusts at the section with geogrid-reinforced soil cover was 85-92% of those with un-reinforced soil cover in the static load tests of the circular structure; this confirms the beneficial effect of soil cover reinforcement on reducing the hoop thrust. However, it was revealed that the two layers of geogrid had no effect on reducing the overburden pressure at the crown level of structure. The obtained values of DLA decrease approximately in proportion to the increase in soil cover from 0.9m to 1.5m. These values are about 1.2-1.4 times higher than those specified in CHBDC.