• Korean Journal of Construction Engineering and Management
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• v.23 no.6
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• pp.111-118
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• 2022

Recently, as underground facilities buried under roads in Korea are aging, the amount of underground facility maintenance work is rapidly increasing. For the maintenance and management of such underground facilities, the cutting work of the road pavement should be preceded. However, the conventional road pavement cutters used in Korea are not eco-friendly, and the reality is that they generate a lot of noise and cutting sludge (scattering dust). Therefore, in this study, the concept of the cutting sludge recovery device was derived, and an eco-friendly pavement cutter including this function was designed and manufactured. The developed equipment took about 20 to 30 seconds to cut 1m to a depth of 100 to 150mm. Also, the sludge suction performance was good in most sections, and the noise level of the equipment briefly measured at a distance of 2m was 82.7dB on average. However, due to the limitation that the developed equipment was at the level of the first prototype, the driving stability was somewhat low, and equipment abnormalities such as engine shutdown and sludge recovery performance decreased in some cases. The cutting performance and sludge recovery function will be more stable through tuning and improvement of the developed prototype in the future. In addition, we plan to quantitatively compare and analyze productivity by applying the improved prototype to actual field conditions.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.242-243
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• 2019

In recent years, road cutting work has been frequently performed for the repair of old road pavement and the development of underground space. However, the existing pavement cutting machine in Korea generates a lot of noise and dust. In this study, it was found out that the pavement cutting machine that cuts off noise and sucks cutting dust is used in overseas. Therefore, in this study, the concept of eco - friendly pavement cutter suitable for domestic situation is derived. The results will be used in prototype modeling and experimentation.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.71-74
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• 2008

This paper aims at studying the key design elements for the optimal ventilation system design, developing the design models and suggesting the design guidelines. The key elements include the basic exhaust emission rate, wall friction coefficient, vehicle drag coefficient and slip streaming effect, jet fan operating efficiency, natural ventilation force and installation scheme for jet fans and ventilation monitors in tunnel. The design models developed in this study are one-dimensional ventilation simulator to analyze the air flow, pressure profile and pollutant dispersion inside and outside tunnel, expert model to choose the optimal ventilation method, and the ventilation characteristic chart to evaluate the preliminary ventilation system. The study results are reflected in the design guideline for road tunnel ventilation system.

• Journal of Auto-vehicle Safety Association
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• v.15 no.1
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• pp.27-34
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• 2023

The registration rate of eco-friendly vehicles, such as hydrogen vehicles, is increasing rapidly, however, few first responders have experienced related accidents. Accident scenarios at hydrogen refueling stations and hydrogen vehicles on a road were investigated, and the relative importance of each scenario was analyzed using AHP analysis. Leakage, jet flame, and explosion that occurred inside and outside the hydrogen refueling station were reviewed, and the hydrogen gas explosion in the compartment showed the highest importance value. In case of the hydrogen vehicle, traffic accident statistics and actual accidents were used. It was analyzed that the hydrogen vessel explosion on the road due to the failure of TPRD and the leakage in the underground parking area were difficult to respond. The developed accident scenarios are expected to be used for first responder training.

• Tunnel and Underground Space
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• v.24 no.5
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• pp.344-353
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• 2014

In this study, the behavior of rock pillar in the diverging area of road tunnel was assessed by using a three dimensional numerical analysis. Based on parameters affecting the behavior of rock pillar, different safety factors according to pillar width, depth and rock conditions were evaluated. It turned out that as the pillar width increases, the change curve of safety factors in accordance with depth and rock conditions shows more of the nonlinear behavior. By the assessment of the minimum safety factor, a safety factor chart on the behavior of rock pillar in the diverging area of road tunnel was suggested.

• Journal of the Korean Society of Industry Convergence
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• v.9 no.1
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• pp.29-35
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• 2006

The population of Daegu, the third biggest city in Korea, is two point six million. Daegu is known as a basin or a city where it is not only too hot in summer but also too cold in winter. Recently with redevelopment apartment house boom, a 40-story or more apartment complexes are under construction near Shin-cheon and Dondaegu-ro, the south-north axis of Daegu. It is necessary to raise several points about blocking a road of the wind by high-rise apartment buildings and apartment complexes. As a kind of the green policy, Daegu enlarge the distance between apartment building by reconstructing low-rise apartment into high-rise and impose a duty of a green space on the ground by making a parking zone into an underground. Through this process, apartment complexes changed from a '一'shape to a '口'shape. It increases heat island phenomenon of a city by blocking a road of the wind that comes from Shin-cheon and Dondaegu-ro. To circulate the polluted air of Daegu basin, we need local wind. There are four effective measures. 1) Throw three greens into one in the center of the road at the north side in the same way of the south side of Dongdaegu-ro, 2) reflect the information of roads of the wind including heights, spaces and directions of buildings, 3) steer clear of a high-rise buildings and development apartment house constructions, and 4)select a city for benchmarking to be the environmental capital.

• Tunnel and Underground Space
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• v.24 no.4
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• pp.308-315
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• 2014

In this study, reduced scale experiments were carried out to evaluate the effect of external wind in a road tunnel fire. Experiments were conducted in a $1.1m{\times}0.5m{\times}50.4m$ tunnel. 4.5 litter gasoline was used as a fuel. Temperature, oxygen and carbon monoxide concentration were measured. Smoke reaching time to the tunnel exit was affected by the external wind. When a fire was fully developed, wind effect is reduced compared with the early stage of a fire. CO concentration was reached at more than 1,500 ppm.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.545-552
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• 2017

Ground subsidence can result in the formation of sinkholes, potholes, settlement of structures, and road subsidence. Road subsidence is described as the sudden collapse of the road surface into subsurface cavities caused by the loss of bearing capacity in the ground, such as the dissolution of limestone by fluid flow in the surface causing the formation of voids leading to subsidence at the surface. Road subsidence occurs about 665 times annually, and this incidence has been increasing until 2013. Damaged underground facilities, management negligence, and lowering of the ground water table have been the causes of road subsidence in Seoul. Seoul metropolitan government announced special management counter plans to relieve the anxieties and make the roads safe for passing. Construction sites, such as excavation works, need to be managed properly because they have strong potential to induce road subsidence. The aim of this study was to identify the main causes of road subsidence and suggest management plans. First, life cycle cost analysis revealed the daytime construction to be more appropriate than nighttime. In addition, by analyzing the limitations of using sand as a backfill material, it is proposed to use a flowable backfill material instead of sand. Finally, to reduce the blind spots, which is a problem in surveying the road pavement conditions of local governments, the road to be managed is divided into several zones, and a specialized agency is selected for each zone and a method of surveying the blind spots through collaboration is suggested.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.1
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• pp.225-234
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• 2018

Domestic urban areas are experiencing serious traffic congestion problems due to continuous population growth and increased traffic volume. In order to solve the problem of traffic congestion, the study of great depth underground double deck tunnels using underground space is being actively carried out in the urban areas. The characteristics of great depth underground double deck tunnels are low in cross section, so the spread of fire smoke is expected to spread faster than the road tunnel in case of fire. Therefore, it is necessary to provide a fire smoke delay device which delays the spread of fire smoke when a fire occurs in a tunnels. In the previous study, the diffusion effect was analyzed according to the blocking area when the fire smoke spread delay device was operated through the 3D CFD in the study of preventing the smoke spread in the case of the tunnel fire. A study on fire smoke diffusion delay device using spring elasticity which is excellent in applicability to a tunnel and economical value is studied. In this study, fire smoke spread delay system was developed to fire smoke delay was experimentally analyzed. Fire smoke delay effect of fire smoke delay device appeared. Therefore, it is considered that the can minimize the damage of the victims when installed in the great depth underground double deck tunnels.

• Journal of the Korean GEO-environmental Society
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• v.16 no.1
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• pp.29-36
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• 2015

Current domestic research is to demonstrate the effectiveness and efficiencies of flood prevention measures through one-dimensional numerical analysis and this study's object is to help water managers to make the efficient decisions by applying the two-dimensional urban run off model XP-SWMM model in the flooded area and comparing with the flood prevention measures. Statistics were analyzed, based on the data collected from Cheongju Weather Service from 1967 to 2011 for 45 years. 50 years Flood frequency simulations of water flow capacity analysis of the target area for flooded areas $539,548m^2$, inundation depth 1.0 m, was analyzed by inundation time of 48 minutes. When comparing with the constructions of bypass road and underground storage facilities to increase the water flow capacity of A1 small drainage areas as flood protection, if you install a batching target underground detention basin with a capacity of $13,500m^3$, it is expected that the flood by rainfall with frequency of 50 years will be resolved completely. In preparation for extreme weather in the future flood mitigation measures, underground storage tank installation is considered a better efficient way.