• Journal of the Korean Geotechnical Society
• /
• v.39 no.11
• /
• pp.23-31
• /
• 2023

The escalating settlements observed in concrete slab tracks pose a significant challenge in Korea, raising concerns about their adverse impact on the safe operation of high-speed railways and the substantial costs involved in restoration. A primary contributor to these settlements is identified as the utilization of rock materials sourced from tunnel construction, incorporated into the lower subgrade without the requisite soil mixing to achieve an appropriate particle size distribution. This study employs numerical analysis to evaluate the efficacy of partial reinforcement in reducing settlements in rock-filled lower subgrades. Column-shaped reinforcement areas strategically positioned at regular intervals in the lower subgrade induce soil arching in the upper subgrade, leading to a concentration of soil loads on the reinforced areas and consequent settlement reduction. The analysis employs finite element methods to investigate the influence of the size, stiffness, and spacing of the reinforced areas on settlement reduction in the lower subgrade. The numerical results guide the formulation of an optimal design approach, proposing a method to determine the minimum spacing required for reinforcements to effectively limit settlements within acceptable bounds. This research contributes valuable insights into addressing the challenges associated with settlement in concrete slab tracks, offering a basis for informed decision-making in railway infrastructure management.

• International Journal of Highway Engineering
• /
• v.10 no.2
• /
• pp.115-124
• /
• 2008

This Study was investigated in main breakage types of 50 interlocking block pavements in apartment houses and evaluated on their performance. According to performance evaluation, maintenance control index of 9 aged interlocking block pavements ranged 7.9 to 8.9. These values meant that the condition of interlocking block pavements were still good. Therefore, it was concluded that the 10-year cycle of the block replacement recommended by Ministry of Construction & Transportation is necessary to reappraise. To objectively evaluate the performance of interlocking block pavements, this study presented the criteria of maintenance control by combining two maintenance control standards suggested by Ministry of Construction & Transportation and the Japan Interlocking Block Pavement Engineering Association. Also, this study suggested that the domestic standard is necessary to include durability standards and quality standards of joint filling materials and bedding sand layer for increasing expectation life and reducing maintenance costs of interlocking block pavements.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.35 no.2
• /
• pp.407-415
• /
• 2015

The railway route and alignment planning have been executed with a limited number of alternatives based on the site pre-survey and the topographic map. This study developed an intelligent railway alignment planning program (ei-Rail) which can derive all the considerable design alternatives and provide the data for the alternative evaluation such as constructions cost, operation cost, and etc. According to the comparisons with prevailing planned railway projects, the time and cost for planning can be reduced as well as the construction costs. This program may contribute to the development of railway industry by reducing the time and cost for planning as well as the total project cost.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.35 no.2
• /
• pp.387-396
• /
• 2015

The existing shield tunnel has constructed in the concept of non-drainage uniformly, but the leak has become a problem in the construction and management. The Shield tunnel design allowed for the water and earth pressure bring about the increasing segment thickness and the construction costs. In order to improve these problems, the study of the partial drainage shield tunnel is in progress. In this study, th model experiment was performed to confirm the possibility of the partial drainage shield tunnel. And the water and earth pressure was measured in drainage and undrained condition. Based on the results of model experiments, the effect of water pressure reduction was confirmed by reviewed the structure stability of the real design case.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.5 no.1
• /
• pp.23-31
• /
• 2003

Since the mid of 1990, permanent shotcrete tunnel linings such as Single-shell and NMT have been constructed in many countries for reducing the construction time and lowing construction costs instead of conventional in-situ concrete linings. Among essential technologies for successful application of permanent shotcrete linings, high performance shotcrete having high strength, high durability and better pumpability has to be developed in advance as an integral component. This paper presents the idea and first experimental attempts to increase early strength and bond strength of wet-mixed Steel Fiber Reinforced Shotcrete (SFRS) in spring water condition. In order to increase early behavior of SFRS, a new approach using high-early strength cement with alkali-free liquid accelerator has been investigated. From the test results, wet-mix SFRS with high-early strength cement and alkali-free accelerator exhibited excellent early compressive strength improvement compared to the ordinary portland cement and good bond strength even under spring water condition.

• Journal of Fisheries and Marine Sciences Education
• /
• v.17 no.2
• /
• pp.193-208
• /
• 2005

The object of this study is to provide a framework of increasing the effectiveness of the R&D planning of experts in fisheries and the education of students with the theoretical background and analytical skills through the adoption of technology roadmapping process in the marine production industry. The study was conducted by fact-finding surveys and the response content for surveys obtained from each expert advisor in the field of fisheries and maritime affairs such as fishery industries, some government organizations and research institutes including the Ministry of Maritime Affairs and Fisheries (MOMAF), National Fisheries Research and Development Institute (NFRDI) and fisheries-related universities was analyzed. The major implementation tasks to effectively achieve the basic goals of technology roadmap for short and middle-term research and development in the fisheries production field are as follows: 1. Research in order to achieve the realization of community-based resource management fisheries or fishermen-oriented co-management fisheries with paradigm shift in fisheries management. 2. Research in order to derive the construction of cost reducing and manpower saving systems in fishery-related science, technology and engineering. 3. Research in order to create the high value-added fisheries products with a focus on the upgrading of processing, freezing and refrigerating facilities, the reduction of logistics costs and the minimization of distribution steps. 4. Research in order to achieve the realization and development of environmental-friendly fisheries and internationally competitive fisheries through restructuring the entire fishing industries, in particular, small-scale fisheries. 5. Research in order to achieve the effective utilization of fisheries resources with a new creation of clean and living marine environment by fisherman under the balanced management and protection of marine living resources and fishing grounds.

• Tunnel and Underground Space
• /
• v.29 no.1
• /
• pp.52-63
• /
• 2019

It is highly in demand to establish a bunker-type underground data center to ensure the safety of national critical data, such as financial information and medical information, and prevent those outflow of national important data. In particular, the security of a data center which is a key national structure has become a social issue due to EMP weapon and earthquakes, but data centers in the nation have not been able to deal with it properly. Therefore, it is necessary to develop an underground data center that is safe from human-induced and natural disasters while reducing power costs by utilizing the benefits of underground spaces such as constant temperature and isolation. In this analysis, the status and trends of data centers around the world were analyzed and based on those trend analyses, the research strategy for underground data center were discussed.

• Convergence Security Journal
• /
• v.23 no.4
• /
• pp.81-92
• /
• 2023

In recent years, the ROK military is promoting Defense Innovation 4.0 with the goal of fostering strong military based on science and technology equipped with artificial intelligence(AI) to prepare for the upcoming population cliff. In particular, at the present time of increased threats of North Korea, the South Korean military is seeking to deal with a decrease in military service resources through the introduction of a Scientific Guard System using advanced technology. TICN which is a core basic communication system to ensure the integrated combat capability of the ROK military is, however, limited to use as a based network for the emerging Scientific Guard System due to the narrow transmission bandwidth with widely spread poor reception area. To deal with this problem, this paper proposes TVWS-based Scientific Guard Systems with TVWS-based wireless network construction technology that has been available for free in Korea since 2017. The TVWS-based Scientific Guard System proposed in this paper, when compared to the existing wired network-based Scientific Guard Systems, has various advantages in terms of minimizing operational gaps, reducing construction costs, and flexibility in installation and operation.

• Journal of the Korean Geosynthetics Society
• /
• v.20 no.1
• /
• pp.9-19
• /
• 2021

This paper deals with the reinforcement performance of acrylate for reinforcing the settled railway roadbed. Concrete tracks have the advantage of reducing track maintenance costs and high resistance to track destruction. However, roadbed settlement is occurring in some construction sections, and the safety of railways is a serious concern because of difficulties in maintenance. Currently, maintenance through the track restoration method is being carried out in Korea as a way of roadbed settlement in concrete tracks, but continuous re-settlement can occur because the roadbed itself cannot be reinforced, and there are very few cases of reinforcement of railway roadbeds and field application. So the development of reinforcement materials and construction methods to reinforce railway roadbeds is required. Therefore, in this paper, acrylate was selected as reinforcement material for railway roadbed, and the reinforcement performance of acrylate was analyzed through experiment. As a result, it was analyzed that the acrylate can penetrate into a permeability coefficient of 1×10^-4 cm/sec, and secure uniaxial compression strength of 0.5 MPa/30min or more and stiffness of 80 MPa or more.

• Journal of the Korea Institute of Building Construction
• /
• v.22 no.1
• /
• pp.11-21
• /
• 2022

Currently, in the domestic construction industry, the free web method has been emerging as a potential solution to the shortage of skilled workers due to the prolonged COVID-19 crisis, as it helps in securing economic feasibility through shortening the construction period and reducing labor costs. To consider one part of the construction method, in this study, the bending behavior according to the load was evaluated for the SY slope-type beam formwork, which was manufactured at a factory, assembled with rebar, brought into the site, and then poured into the site. For the SY Beam standard cross-sectional shape, a cross-sectional dimensional width of 400mm and depth 600mm determined through structural modeling using the MIDAS GEN program were applied. A total of 6 specimens were made with a member length of 5,000mm, 5 specimens and one RC specimen in the comparison group were manufactured in real-size format using the thickness of the steel plate(0.8, 1.0, 1.2mm) as a variable, and bending experiments were performed. In the bending test, the steel plate deck showed high initial stiffness and maximum strength as it yielded, which showed that it sufficiently contributed to the flexural strength. It is judged that additional analysis and experimental studies for 1.05, 1.1, and 1.15mm are needed to derive the appropriate steel plate thickness and the method for calculating the tensile force contribution of the steel plate to secure the manufacturing, construction and economic feasibility of SY Beam in the future.