• Geophysics and Geophysical Exploration
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• v.11 no.4
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• pp.350-360
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• 2008

Electrical resistivity is one of physical property of the earth and measured by electrical resistivity survey, electrical resistivity logging and laboratory test. Recently, electrical resistivity is widely used in determination of rock quality in support pattern design of road and railway tunnel construction sites. To get more reliable rock quality data from electrical resistivity, it needs a lot of test and study on correlation of resistivity and rock quality. Firstly, we did rock property test in laboratory, such as P wave velocity, Young's modulus, uniaxial compressive strength (UCS) and electrical resistivity. We correlate each test results and we found out that electrical resistivity has highly related to P wave velocity, Young's modulus and UCS. Next, we accomplished electrical resistivity survey in field site and carried out electrical resistivity logging at in-situ area. We also performed rock classification, such as RQD, RMR and Q-system and we correlate electrical resistivity to RMR data. We found out that electrical resistivity logging data are highly correlate to RMR. Also we found out that electrical resistivity survey data are lower than electrical resistivity logging data when there are faults or fractures. And it cause electrical resistivity survey data to lowly correlate to RMR.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.4
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• pp.257-262
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• 2019

Lattice steel towers for overhead transmission lines have been replaced by tubular steel poles due to the visual impact of large and complex shape of truss type. Demand for tubular steel poles consisting of a single frame member continues to grow because of its advantages such as visual minimization, architectural appeal and minimal site consumptions. However, there are some constraints on the transportation and construction. As the diameter of tower base has been enlarged, it may exceed minimum height limit required to pass the tunnel in case of land transportation. Also, in a narrow place where it is not easy to secure the installation areas such as mountainous places, there might be some areas wherein it must secure a wide working space so that large vehicles and working cranes will be allowed to enter. In this paper, we presented a vertical separated tubular steel pole, which is a new type of support that can be implemented for general purpose such as mountainous areas or narrow areas to improve the issues raised by breaking away from the conventional design and fabrication methods. Technical approaches for overcoming the limit of the cross-sectional size is to separate and modularize the cross-section of the tubular steel pole designed with a size that cannot be carried or assembled, and to lighten it with a weight capable of being transported and assembled in a narrow space or mountainous area. As a result of this research, it will be possible to enter small and medium sized vehicles in locations where it is restricted to transport by large-sized vehicles. In the case of mountainous areas, it will be possible to divide it into a weight capable of being carried by a helicopter and it will be easy to adjust and fabricate it with individual modules. Furthermore, in order to break away from the traditional construction method, we proposed the equipment that can be applied to the assembly of Tubular Steel Pole without using a large crane in locations where there is no accessible road or in locations wherein large cranes cannot enter. In particular, this paper shows the movable assembling equipment and some methods that are specialized for vertical separated tubular steel pole consisting of members with reduced weight. The proposed assembly equipment is a device for assembling the body of the Tubular Steel Poles. It will be installed inside the support and the modules can be lifted by using the support itself.

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.6
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• pp.511-524
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• 2016

Since a room-and-pillar underground structure is characterized by its grid-type array of room and pillar, its economical efficiency can be governed by excavation sequence. In this study, the construction period by the drill-and-blast method as a excavation method for a room-and-pillar underground structure was examined. In addition, the parallel excavation sequence was considered as the main sequence of a room-and-pillar underground structure. Sequences of mucking and support installation were derived to estimate the total excavation cycle by taking the case of a road tunnel into consideration. From the excavation cycle of room-and-pillar underground structure, the relationship between available maximum and minimum numbers of jumbo drill machines depending on the number of faces in operation was suggested.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.1
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• pp.74-85
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• 2013

Since the underground transportation system is a closed environment, indoor air quality problems may seriously affect many passengers' health. The purpose of this study was to understand $PM_{10}$ characteristics in the underground air environment and further to quantitatively estimate $PM_{10}$ source contributions in a Seoul Metropolitan subway station. The $PM_{10}$ was intensively collected on various filters with $PM_{10}$ aerosol samplers to obtain sufficient samples for its chemical analysis. Sampling was carried out in the M station on the Line-4 from April 21 to 28, July 13 to 21, and October 11 to 19 in the year of 2010 and January 11 to 17 in the year of 2011. The aerosol filter samples were then analyzed for metals, water soluble ions, and carbon components. The 29 chemical species (OC1, OC2, OC3, OC4, CC, PC, EC, Ag, Al, Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Si, Ti, V, Zn, $Cl^-$, $NO_3{^-}$, $SO_4{^{2-}}$, $Na^+$, $NH_4{^+}$, $K^+$, $Mg^{2+}$, $Ca^{2+}$) were analyzed by using ICP-AES, IC, and TOR after proper pretreatments of each sample filter. Based on the chemical information, positive matrix factorization (PMF) model was applied to identify the $PM_{10}$ sources and then six sources such as biomass burning, outdoor, vehicle, soil and road dust, secondary aerosol, ferrous, and brakewear related source were classified. The contributions rate of their sources in tunnel are 4.0%, 5.8%, 1.6%, 17.9%, 13.8% and 56.9% in order.

• Spatial Information Research
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• v.10 no.2
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• pp.247-261
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• 2002

There are much damage of people and property because of heavy rain every year. Especially, there are problem to major facility such as dam, bridge, road, tunnel, and industrial complex in the ground stability. So the counter plan for landslide or ground failure must be necessary In the study, the technique of regional landslide susceptibility assessment near the Ulsan petrochemical complex and Kumgang railway bridge was developed and applied using GIS. For the assessment, the geological structures such as bedding and fault were surveyed and the geological structure, topographic, soil, forest, and land use spatial database were constructed using CIS. Using the spatial database, the factors that influence landslide occurrence, such as slope, aspect, curvature and type of topography, texture, material, drainage and effective thickness of soil, type, age, diameter and density of forest, and land use were calculated or extracted from the spatial database. For application of geological structure, the geological structure line and fault density were calculated. Landslide susceptibility was analyzed using the landslide-occurrence factors by probability method that is summation of landslide occurrence probability values per each factors range or type. The landslide susceptibility map can be used to assess ground stability to protect major facility.

• Tunnel and Underground Space
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• v.23 no.5
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• pp.353-361
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• 2013

Previous studies for analyzing optimal haulage routes of dump trucks in open pit mines mostly used raster data. However, the raster data has several problems in performing optimal route analyses: (1) the jagged appearance of haulage roads according the cell resolution often causes overestimation of the travel cost; (2) it difficult to trace the topological relationships among haulage roads. These problems can be eliminated by using vector network data, however a new method is required to reflect the performance characteristics of a dump truck according to terrain gradient changes. This study presents a new method to create vector network data with the consideration of terrain gradient for analyzing optimal haulage routes of dump trucks in open pit mines. It consists of four procedures: (a) creating digital elevation models, (b) digitizing haulage road networks, (c) calculating the terrain gradient of haulage roads, and (d) calculating the average speed and travel time of a dump truck along haulage roads. A simple case study at the Roto South pit in the Pasir open pit coal mine, Indonesia is also presented to provide proof that the proposed method is easily compatible to ArcGIS Network Analyst software and is effective in finding optimal haulage routes of dump trucks with considering terrain gradient in open pit mines.

• The Journal of Engineering Geology
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• v.10 no.2
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• pp.18-35
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• 2000

The most dominant type of landslide in Korea is debris flows which mostly take place along mountain slopes during the rainy season, July to August. The landslides have been reported to begin activation when rainfall is more than 200mm within 2days. The debris flows are usually followed by translational slips which occur upper part of mountain slopes and they transit to debris flow as getting down to the valleys. Lithology, location, slope inclination, grain size distribution of soil, permeability, dry density and porosity have been proved as triggering factor causing translational slides. The triggering data taken from mapping are statistically analysed to get landslide potential quantitatively. Rock mass creeps mostly occur on well bedded sedimentary rocks in Kyeongsang Basin. Although the displacement of rock mass creep is relatively small about 1m, the creep can cause severe hazards due to relatively large volume of the involved rock mass. Examples are rock mass creep occurred in the mouth of Hwangryongsan Tunnel, in Chilgok and in Sachon in 1999. Although the direct factor of the creeps are due to slope cutting at the foot area, more attention is required A rotational slide occurring within thick soil formation or weathered rock is also closely related to bottom part of slope cutting. It is propagated circular or semi-circular type. Especially in korea, the rotational slide may be frequently occurred in Tertiary tuff area. Because they are mainly composed of volcanic ash and pyroclastic materials, well developed joints and high degree of swelling and absorption can easily cause the slide. The landslide among the Pohang-Guryongpo national road is belong to this type of slide.

• Journal of Digital Convergence
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• v.15 no.12
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• pp.313-321
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• 2017

Traffic accidents in the country have steadily increased. Although IOT technologies have been applied so as to prevent the primary accident, practical solutions to prevent the secondary accident have not been suggested. A general guideline is simply recommended. In this paper, utilizing existing communication technology, we implement a proposed model and its simulation to prevent the secondary accident. When it is possible for a driver to secure visibility, the secondary accident can be prevented; In areas like tunnel, mountain terrain, and curve road with heavy traffic, where the driver has difficulty in securing the visibility, the secondary accident rates after the primary accident have been increasing. Therefore, we implement an accident prevention system that determines the primary accident utilizing sensor technology and prevents the secondary accident communicating through V2V or V2I. After the simulation, we found that the proposed model and the existing model made no difference with regard to the secondary accident rates when the visibility of the driver is secured; With the application of the proposed model, however, the accident rates decreased for 3-7 percent even though the visibility and communication were not secured.

• The Journal of Engineering Geology
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• v.12 no.2
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• pp.167-178
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• 2002

Properties of discontinuity for Seoul Granite in northeastern part of Seoul City were analyzed by dividing structural domains into Surak and Bulam Mtn. areas. Important parameters measured among several engineering properties of a rock during tunnel excavation and road construction are as follows: 1) Orientation of joint, 2) joint spacing, 3) joint density, and 4) uniaxial compressive strength. Orientation, spacing, and density of joints can be directly measured during field investigation using scanline survey, circle-inventory method, and window survey. Uniaxial compressive strength of the rock was calculated by a simple correlation equation although it is originally necessary to prepare core samples in measuring it. Major orientations of joints measured from both areas are 3 sets of joints with different orientations. In other words, they are 2 sets of orthogonal joint and 1 set of sheet joint that is dipping at low angle, and have very similar orientations in both areas. Joint densities in both areas range from 0.039 and 0.066/cm, and average joint length are between 1.30 and 4.52m. Average joint spacing also has values from 10.3cm up to 59.6cm, and shows significant difference along specific orientation of scanlines measured. Values of uniaxial compressive strength calculated on the basis of Schmidt hammer rebound values range from 217 to 335 MPa, which indicates very strong rock type by classification of wall strength.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.272-278
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• 2018

Traffic volume has been greatly increasing due to urban development and the improvement of living standards, and many complaints are being raised due to the increasing road noise. As a countermeasure against these problems, highly soundproof walls are installed on the sides of roads. However, the ability to bear wind loads is a major design requirement for soundproof walls, which contributes to the exponential increases in construction costs and restricts the height of the walls. The aim of this study is to improve the performance of soundproof walls and to dramatically reduce wind loads while maintaining excellent price competitiveness. Based on Helmholz's resonator theory, a new concept is proposed for a ventilation-type soundproofing plate that can pass through a fluid like air and reduce noise. A full-scale metal soundproofing plate was produced to satisfy the quality standards of highways by conducting a sound-pressure transmission-loss test, wind tunnel test, and material quality test. To verify the reliability, the wall was manufactured and installed, and the sound insulation effect was examined by measuring the noise over time. In the future, ventilated soundproof walls on roads could create a pleasant living environment due to the high noise-insulation effect.