• Tunnel and Underground Space
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• v.25 no.1
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• pp.37-45
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• 2015

Recently, many cities have always been affected by large natural disasters such as floods and landslides. As climate change causes more frequent localized heavy rains exceeding the conveyance capacity of sewer, flood damage is expected to increase. For the sake of reducing the urban flood damage by changed rainfall, there has been many trials on installation of runoff-reducing facilities. Therefore, it was required to study about reasonable analysis and countermeasure of rainwater storage facility project for extending it. This study was to review the status of rainwater storage facility project for the urban disaster prevention in Busan, to find out problems, and to propose the countermeasure of rainwater storage facility project for the urban disaster prevention.

• Geomechanics and Engineering
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• v.10 no.3
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• pp.325-334
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• 2016

Rock salt is a near-perfect material for gas storage repositories due to its excellent ductility and low permeability. Gas storage in rock salt layers during gas injection and gas production causes the stress redistribution surrounding the cavity. The triaxial cyclic loading and unloading tests for rock salt were performed in this paper. The elastic-plastic deformation behaviour of rock salt under cyclic loading was observed. Rock salt experienced strain hardening during the initial loading, and the irreversible deformation was large under low stress station, meanwhile the residual stress became larger along with the increase of deviatoric stress. Confining pressure had a significant effect on the unloading modulus for the variation of mechanical parameters. Based on the theory of elastic-plastic damage mechanics, the evolution of damage during cyclic loading and unloading under various confining pressure was described.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1997.11a
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• pp.404-412
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• 1997

The pipes and cables buried below ground, which may have helped to improve city landscape, is becoming direct and indirect causes for various kinds of disaster in Korea. Every advantage from the use of utility tunnel can not be converted in a dollar since there is associated huge contribution to safe urban environment. The Korean government has a certain role to play in helping promote utility tunnels for the past years. Most recently, many utility tunnels have been being checked to find out safety level, especially fire safety level, and main problems and shortcomings are checked out as a result of this survey. Because the fire safety level of existing tunnel is low, possible approaches and solutions are presented according to the analysis of fire safety level. In order for these approaches to be effective, existing tunnel should be supplemented appropriately and extra equipment must be installed according to the solutions. Hopefully, by performing both improvement of existing utility tunnel that provide a fire/disaster proof and introducing new types of tunnel which influence utility management and maintenance, the recent disaster rate in Korea can be diminished up to a desirable rate in a near future.

• Smart Structures and Systems
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• v.29 no.3
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• pp.475-484
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• 2022

The loss of cable tension for civil infrastructure reduces structural bearing capacity and causes harmful deformation of structures. Currently, most of the structural health monitoring (SHM) approaches for cables rely on contact transducers. This paper proposes a cable tension identification technology using percussion sound, which provides a fast determination of steel cable tension without physical contact between cables and sensors. Notably, inspired by the concept of tensioning strings for piano tuning, this proposed technology predicts cable tension value by deep learning assisted classification of "percussion" sound from tapping a steel cable. To simulate the non-linear mapping of human ears to sound and to better quantify the minor changes in the high-frequency bands of the sound spectrum generated by percussions, Mel-frequency cepstral coefficients (MFCCs) were extracted as acoustic features to train the deep learning network. A convolutional neural network (CNN) with four convolutional layers and two global pooling layers was employed to identify the cable tension in a certain designed range. Moreover, theoretical and finite element methods (FEM) were conducted to prove the feasibility of the proposed technology. Finally, the identification performance of the proposed technology was experimentally investigated. Overall, results show that the proposed percussion-based technology has great potentials for estimating cable tension for in-situ structural safety assessment.

• Journal of the Korea Safety Management & Science
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• v.26 no.2
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• pp.1-10
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• 2024

Human stampedes were a major hazard that could occur during mass gatherings, but they have received limited attention in korea. However, after the 10.29 Itaewon disaster, this atmosphere has turned around. The cause of such an accident and how to prevent it should be considered. The main aim of this study is to identify the reason why did the accident happen at that time, the root cause, and the triggering cause with Delphi-AHP survey method. In addition, various preventive measures were investigated by experts to prevent accidents similar to 10.29 Itaewon disaster. Problems and solutions were presented by collecting expert opinions on the causes and preventive measures of the 10.29 Itaewon disaster. However, the opinion of the experienced peoples who experienced the risk at the Itaewon was not included, so further investigation is considered necessary.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.1
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• pp.15-29
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• 2020

Recently, the incidence of flooding in Korea has decreased by the measures by central and local governments, however the scale of damage is increasing due to the improvement of living standard. One of the causes of such flood damage is natural causes such as rainfall exceeding the planned frequency of flood control under climate change. In addition, there are artificial causes such as encroachment of river spaces and management problems in upstream basins without consideration of downstream damage potential by regional development flood. In this study, in order to reduce the inundation damage caused by flooding of river, the situation at the time of inundation damage was reproduced by the detailed topographic data and 2D numerical model. Therefore, the effect of preparing various disaster prevention measures for the lowland was simulated in advance so that quantitative evaluation could be achieved. The target area is Taehwa river basin, where flooding was caused by the flooding of river waters caused by typhoon Chaba in October 2016. As a result of rainfall-discharge and two-dimensional analysis, the simulation results agree with the observed in terms of flood depth, flood arrival time and flooded area. This study examined the applicability of hydraulic analysis on river using two-dimensional inundation model, by applying detailed topographic data and it is expected to contribute to establish of disaster prevention measures.

• Proceedings of the Safety Management and Science Conference
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• 2011.11a
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• pp.23-34
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• 2011

Recently, carelessness on safety management in construction sites has caused a sharper upward trend in accidents and disasters, compared to the past. Therefore, this study analyzes the causes of accidents that occurred on construction sites in the year of 2010, and proposes preventive measures. The construction industry had a heavy death rate with 279 out of 418 deaths from falls in all industrial sites, accounting for 66.7%. And the causation analysis found a particularly high incidence of temporary structure-related accidents, with falling off scaffolding as the most common cause of accidents. According to the causation analysis of fall-down accident cases, accidents induced by protrusion on construction sites are a big contributor resulting in the deaths of 312, accounting for 74.8%, which is deemed to be due to site disorderliness. And to remove floor protrusions and to secure workers' traffic line and safety, neat and thorough site arrangement is necessary. Against collision, efforts must be made to prevent equipment-pedestrian crashes on site, which necessarily requires emergency lamps, alarm bells, and safety poles and blocks to be installed, lighting systems to be improved, obstacles to be removed, site supervisors to be assigned to construction equipment works, and workers to be more intensely trained and supervised.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.677-694
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• 2009

While the budget has been allocated more for repairs and reinforcements, casualties are gradually increased due to slope disaster. Slope disaster causes road damaged as well as casualties. It also causes significant social and economic loss. The measurement device, which is installed inside ground of slope like inclinometer, has the high loss rate when slope is being slided. The electric type and the vibrating wire type have low durability because of corrosion. To cover the demerit of the present slope monitoring, the measurement method using the Multi-Antenna GPS has been developed. The Multi-Antenna GPS has been installed in the local slope as the regular monitoring system for slope. Although the initial cost of the Multi-Antenna GPS for installation is high, the additional cost is low. So it is the suitable method for large slope. The regular monitoring system using the Multi-Antenna GPS is the suitable measurement method for watching slope collapse, which is occurred widely, because it is economical, has high durability, and collects data with high resolution.

• Journal of the Korea Institute of Building Construction
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• v.8 no.3
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• pp.127-133
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• 2008

Safety accident resulting from construction projects getting larger and complex day by day has occurred more often than ever. Particularly, the accident caused by construction equipment, among others, has been on the rise. To prevent such accidents, it's necessary to come up with the measures for reducing the accident. In this study, the cause of safety accidents was analyzed, reviewing the cases of safety accident maintained by Korea Occupational Safety & Health Agency, and the measures for reducing the accident was suggested with computerized safety checklist. The scope of study was limited to excavator, and the result is summarized as below. 1) Investigation was conducted to identify the cases of accident by excavator with the primary causes. 2) Reduction measures were suggested by category of cause of excavator-caused accident. 3) Checklist to prevent the safety accident, which was based on primary causes, was suggested. 4) The measures to stir up safety consciousness and monitor the safety were suggested, making use of computerized system. This study is expected to lay the foundation for further study in future as well as make a great commitment to reducing the safety accident.

• Journal of the Korea Safety Management & Science
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• v.14 no.1
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• pp.7-13
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• 2012

Recently, carelessness on safety management in construction sites has caused a sharper upward trend in accidents and disasters, compared to the past. Therefore, this study analyzes the causes of accidents that occurred on construction sites in the year of 2007, and proposes preventive measures. The construction industry had a heavy death rate with 279 out of 418 deaths from falls in all industrial sites, accounting for 66.7%. And the causation analysis found a particularly high incidence of temporary structure-related accidents, with falling off scaffolding as the most common cause of accidents. According to the causation analysis of fall-down accident cases, accidents induced by protrusion on construction sites are a big contributor resulting in the deaths of 312, accounting for 74.8%, which is deemed to be due to site disorderliness. And to remove floor protrusions and to secure workers' traffic line and safety, neat and thorough site arrangement is necessary. Against collision, efforts must be made to prevent equipment-pedestrian crashes on site, which necessarily requires emergency lamps, alarm bells, and safety poles and blocks to be installed, lighting systems to be improved, obstacles to be removed, site supervisors to be assigned to construction equipment works, and workers to be more intensely trained and supervised.