• Journal of the Korean Society of Safety
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• v.30 no.6
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• pp.122-131
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• 2015

Recently, starting with the deep underground road construction plan in Seobu Expressway, Korea, there area many studies on deep underground roads to be newly built. However, there is an extreme lack of safety standards, which does not consider traffic conditions and road driving characteristics. Therefore, this study reviewed safety elements to reflect in the deep underground road planning by analyzing driving stability of longitudinal tunnels with road environments, which resemble deep underground roads. For comprehensive analysis, the characteristics and causes of the accidents that have occurred in seven longitudinal tunnels with a length of 2km or over in Gangwon area, were collected. Specifically, geometric structures and facilities of each tunnel were investigated. Also, the present state of facility installation and the changes in driving speed of vehicles passing through each tunnel were observed to analyze the causes for the traffic accidents in each tunnel and accident reduction alternatives. It was revealed that the most frequent accidents in the tunnels resulted from the changes of traffic flow due to the abrupt speed reduction of forward vehicles, or the failure in speed control of following vehicles during the traffic congestion situation. Moreover, installing facilities such as plane and longitudinal curves, median strips and marginal strips seem to induce consistent driving speed. These results mean that for accident prevention, speed management must be preceded and there is a need to develop and introduce safety facilities actively to control the driving flow of forward and following vehicles.

• Journal of the Korean Geosynthetics Society
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• v.15 no.4
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• pp.9-16
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• 2016

During the 2004 Niigata-ken Chuetsu, Japan, earthquake, more than 1,450 underground structures, known as sewer manhole, were uplifted up to 1.5m in Nagaoka and Ojiya city. The uplift damage can be a serious matter because they not only hinder the flow of wastewater systems, as a part of lifeline systems, but also disturb traffic flows. For restoration works, an open-cut investigation of damaged wastewater system was conducted by the Nagaoka city government. The results from the investigation compiled valuable data sets for buried pipeline damage due to earthquakes. In the present study, the factors affecting the uplift amount of the underground structure is investigated by using the data sets which include locations of damaged sections and inclination of pipeline before and after the earthquake and the SPT borehole logs in the affected area. Correlation analysis between the underground structure uplift and the geological settings in the affected area revealed that ground water depth and original subsoil, including thickness of clay layer, SPT N-value and fill thickness are the key parameters for the uplift phenomenon.

• Explosives and Blasting
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• v.38 no.4
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• pp.1-15
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• 2020

With the increase of the utilization of underground space in Korea, explosion accidents at the underground facilities such as gas pipes have occurred frequently. In urban area with high population density, individual explosion accidents are likely to spread into large complex accidents. It is necessary to investigate the effect of explosion on the stability of underground structures in urban area. In this study, a sensitivity analysis was carried out to investigate the possible influence of nearby explosion on the stability of underground structure with 8 parameters including explosion conditions and rock properties. From the sensitivity analysis using AUTODYN, the main and interaction effects of each parameters could be determined. From the analysis, it was found that the distance between explosion point and tunnel, charge weight, and Young's modulus are the most important parameters on the stress components around a tunnel.

• Journal of the Korean Association of Geographic Information Studies
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• v.24 no.4
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• pp.164-173
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• 2021

Recently, as underground space safety issues such as sink hole, ground subsidence and damage to old underground facilities have been increasing in urban areas, the precise management of underground facilities ins more required. Thus, this study developed a function to that, visualize on Integration Map of Underground Geospatial Information a real-time survey data of underground facilities acquired on site or underground facility survey data acquired through on-site survey after underground facility exploration and developed a function convert to surveying-results. In addition, using the on-site survey performance utilization function in connection with the Integration Map of Underground Geospatial Information developed through this study, the surveying -results obtained with the Total-station at the water pipeline burial construction site in Eunpyeong-gu, Seoul are visualized on the Integration Map of Underground Geospatial Information and On-site verification was performed by converting spatial-information performance files and transmitting the Integration Map of Underground Geospatial Information to the mobile center. Based on this, it was possible to verify the work procedure using the surveying-results in the area where the Integration Map of Underground Geospatial Information was built, and to review the direction of future improvement directions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.7
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• pp.1180-1187
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• 2006

We Studied the method of structuring the sign system for pedestrians in the underground space by investigating and analyzing the sign system at Tae-jon Underground Commercial Area in Korea by 1) classifying the signs by types and comparing their numder for each type in sections, 2) classiflying the signs by the points of installation, types, functions and contents of information and comparing their numbers, 3) classifying the signs by their height and comparing by the points of installation, and 4) classifying the signs by their points of installation finding patterns. As a result, we found out that the current pedestrian signs in Tae-jon Underground Commercial Area could by classified into those installted with a certain regularity and those concentrated in at certain points. We also found out that there were many problems with the current signs system. The big gap of the type and numble of the signs, concentration of the signs at the gate (entrance), and the big gap of the function of the signs by their points of installation. And the gap of the signs by the number of installation is big between the North side and the South side. Most of signs concentrated in the South side show the problems of installation attached by the types and quantity of information. We suggest that type of information has consistency by posting of signs, at the same time, the necessary information should be offered in order for the pedestrians to easily recognize as they more in the Underground space.

• Journal of the Society of Disaster Information
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• v.16 no.1
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• pp.123-132
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• 2020

Purpose: In this study, the authors propose a flood evacuation plan for skyscrapers with law related to underground space of skyscrapers, domestic and international underground space flood case study and simulation test. Method: This study compares the evacuation pattern of various case from flooded underground spaces extending over several floors with respect to the number of evacuation routes with. Also, simulation test was performed by setting up the virtual underground spaces consisting of three-stories basement and changing the number of the ground entrance, area of the basement and the flooding heights of the basement. Result: There was no difference in evacuation route according to the inundation risk even if there was an area corresponding to risk level 4. This is because the risk in the starting area is greater than that in the evacuation route. Especially, even if the risk of evacuation route increases with time, there is no change in route because the route must be passed to reach the evacuation site. Conclusion: In this study, there was no difference in evacuation route according to the inundation risk. However, if the size and shape of the underground space of each building is different, the depth of inundation with time may be different.

• Journal of the Korean Geotechnical Society
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• v.37 no.10
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• pp.77-87
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• 2021

Several studies have been conducted to analyze, predict, and prevent the risk of ground subsidence occurring in urban areas. Nevertheless, there is insufficient research effort on risk analysis that utilizes the correlation between the density of underground structures (i.e., the spatial quantity of buried objects installed in the ground around the interested area) and the occurrence of ground subsidence. In this paper, a study was conducted to analyze the line density of underground structures using GIS-based spatial information data, and to link this with the recorded ground subsidences. An optimization algorithm was developed to maximize the correlation between the line density of 29 recorded ground subsidences and 6 types of underground structures that occurred between 2010 and 2015 for the analysis area. The concept of normalized line density was also proposed for the analysis. The normalized line density of the analysis area was divided into five grades (Grade 1: lowest, Grade 5: highest). When the optimization algorithm was applied, the case where the normalized line density was Grade 4 or higher at the location of the recorded ground subsidences was about > 80%. It is thought that the density analysis result of underground facilities can be applied to the ground subsidence risk analysis by using the proposed optimization algorithm.

• Korean Journal of Construction Engineering and Management
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• v.17 no.4
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• pp.87-94
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• 2016

The necessity to consider stability of underground structures constructed below or adjacent ammunition depots has been increased since the expansion of urban area and construction of infrastructure. However, there are a few studies on influence of accidental explosion on underground structures. In this study, the process of assessing the stability of underground structures is suggested and its applicability is verified through the case study. AUTODYN and SPACECLAIM are used to execute the structure and geotechnical modelling, and explosion effect is simulated and vibration velocities are calculated. According to the result of this case study, it is concluded that underground structure constructed 70m below ground might be rarely influenced by the simulated explosion. The process used in this study could be used to design the underground ammunition complex and analyse the stability of underground facilities being influenced by periodical vibration.

• Journal of the Korean GEO-environmental Society
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• v.22 no.11
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• pp.23-29
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• 2021

Recently, ground subsidence has been steadily occurring mainly in downtown areas, threatening the safety of citizens. Under the road, various underground facilities such as water supply pipe, sewage pipe, and communication pipe are buried. Due to the aging of these underground facilities and the reckless development of the underground, it is acting as a cause of ground subsidence. Although there is a result of analyzing the risk of ground subsidence according to the deterioration of the existing pipeline, there is no result of analyzing the risk of ground subsidence using the density of pipelines indicating ground disturbance. Therefore, in this study, the density of the underground space was analyzed using the data of six types of representative underground pipelines in Seoul, and a study was conducted on whether there is a correlation with the ground subsidence. As a result, it was found that the density of underground facilities is high in the area where the ground subsidence occurred, indicating that the density of pipelines have an effect on the ground subsidence.

• Journal of Korean Society of Disaster and Security
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• v.11 no.2
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• pp.17-28
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• 2018

The purpose of this study is to investigate the effect of underground facilities around excavation zone on groundwater flow characteristics during excavation. The scenarios were constructed considering the size of the underground facility, the separation distance, and the hydraulic gradient. As a result, as the size of the underground facility increases, the difference of head and the hydraulic gradient become large. The shorter the separation distance of underground facility is, the more the difference of head and the hydraulic gradient occur. The effect of hydraulic gradient on model area was relatively small. As a result of analysis of groundwater flow rate for the scenario, groundwater flow rate tends to decrease as the size of underground facility increases or groundwater flow rate tends to decrease as the separation distance decreases. It is necessary to examine the effect of underground facilities on the groundwater flow analysis in the ground excavation.