• Journal of the Korean GEO-environmental Society
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• v.13 no.1
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• pp.15-20
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• 2012

Field measurement is a very essential factor for economic aspect and estimation of stability of tunnels. In this paper, various types of support element based on field test data in 4-lane wide road tunnel were evaluated. And stability and economical efficiency were also estimated. The estimated value were compared with design value and the type of support element which is applicable to site condition was evaluated. The results show that most of support elements were modified under the standard value(30mm) and type of support element which is already constructed was overestimated. So, appropriate level of support element have to be presented to save the time and cost during construction.

• Journal of the Korean GEO-environmental Society
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• v.17 no.9
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• pp.13-20
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• 2016

This study carried out field measurements of rock drilling where two PRD (Percussion Rotary Drilling) methods, T-4 drilling method and dual drilling method, were considered and the study examined the characteristics of vibration level, noise level, drilling speed, and drillig verticality of the two method. The results of field measurements were compared and analyzed in details to provide the drilling information so that the problems due to rock drilling is minimized and the drilling efficiency is improved in the future. The limited measurements in the field indicated that the dual drilling method showed lower vibration and noise levels and better drilling speed and verticality.

• Journal of the Korean GEO-environmental Society
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• v.13 no.8
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• pp.5-13
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• 2012

This research have investigated the application and the injection effect of the alkaline silicasol grouting materia (which is) recently developed. To compare the engineering characteristics of the alkaline silicasol which is formed with 3D-gel and the sodium silicate, it have studied the strength and environmental effects through the laboratory test, and field application was investigated with a review of the injection effect and waterproof through the field test. As a result of the laboratory test, unconfined compression strength of alkaline silicasol was 5 times more than sodium silicate. As a result of the leaching test, a total amount of the eluviated elements was very small, it considered the environment-friendly material. As a result of the field test, considerable reduction of the coefficient of permeability at the hydraulic layer was confirmed, and it could secure that the coefficient of permeability showed a lower than standard value of $10^{-5}cm/sec$.

• Journal of the Korean GEO-environmental Society
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• v.13 no.8
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• pp.25-33
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• 2012

Although it is important to reflect the accurate information of the ground condition in the tunnel design, the analysis and design are conducted by limited information because it is very difficult to consider various geographies and geotechnical conditions. When the tunnel is under construction, examination of accurate safety and prediction of behavior are overcome the limits of predicting behavior by Artificial Neural Network in this study. First, construct the suitable structure after the data of field was made sure by the multi-layer back propagation, then apply with algorithm. Employ the result of measured data from database, and consider the influence factor of tunnel, like supporting pattern, RMR, Q, the types of rock, excavation length, excavation shape, excavation over, to carry out the reliable analysis through field applicability of Artificial Neural Network. After studying, using the ANN model to predict the shearing displacement, convergence displacement, underground displacement, Rock bolt output follow the excavation over of tunnel construction field, then determine the field applicability with ANN through field measured value and comparison analysis when tunnel is being constructed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.2
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• pp.195-204
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• 2016

In this paper, the applicability and usefulness of windprofiler input data were investigated to generate three dimensional wind field. A logical diagnostic model CALMET with windprofiler data at ten sites and with weather forecasting model WRF output was evaluated by statistically comparing with the radiosonde data at eight sites. The horizontal wind speed from CALMET simulated with hourly windprofiler data is in good agreement with radiosonde observations within 1.5 m/s of the root mean square error, especially local circulation of wind such as sea breeze over the coastal region. The root mean square error of wind direction ranged $50^{\circ}{\sim}70^{\circ}$ is due to the wind direction error from the windprofiler polluted by ground clutters. Since the exact wind can be produced quickly and accurately in most of the altitude with windprofiler data on CALMET, we expect the method presented in this study to be useful for the monitoring of safe environment as well as weather in the coastal zone.

• The Journal of Engineering Geology
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• v.26 no.1
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• pp.129-142
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• 2016

National parks, which are located mainly in mountainous areas, are always at risk of damage by landslides. The goal of this study is to establish a method for systematically maintaining hazardous steep slopes along trails in national parks. We produced a checklist suitable for each of the 19 national parks nationwide and investigated 183 slopes. The aim of these investigations is to recommend appropriate slope-stability countermeasures, including field investigations and stability analysis. We made preliminary investigations at specific sites, evaluating the slope hazard using specialized equipment such as terrestrial LiDAR. An investment priority formula was developed, and ranking and hazardous grades were calculated as part of a long-term maintenance plan. Finally, to systematically manage dangerous slopes and to house all the field data within one system, we developed the "Slope Maintenance System in National Parks" based on web server that can show various information for slopes.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• v.10 no.2
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• pp.349-352
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• 2005

• The Journal of Engineering Geology
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• v.24 no.3
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• pp.343-351
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• 2014

Tunnel face mapping plays an important role in risk analysis and infrastructure support decisions during tunnel construction. In this study, a digital mapping system using a mobile device is employed instead of existing face-mapping methods that rely upon face mapping sheets. The mobile device is then connected to the main server in the field, where a tunnel-specific database is compiled automatically. This information provides real-time feedback on the tunnel face to construction personnel and engineers, thus allowing for rapid assessment of tunnel face stability and infrastructure needs. The Douglas-Peucker algorithm, among others, is employed to resolve problems arising from the detailed mapping and speed problem by data accumulation. This system is expected to raise program optimization through field verification and additional functional improvements.

• Economic and Environmental Geology
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• v.54 no.1
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• pp.91-103
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• 2021

In order to estimate the vertical and horizontal structural in the Yangsan fault core line (Naengsuri area, Pohang), we carried out gravity field measurements and interpretation procedures such as Euler deconvolution method and curvature analysis in addition to the forward modelling technique (i.e. IGMAS+). We found a prominent gravity difference of more than 1.5 mGal across the fault core. This indicates a distinct density difference between the western and eastern crustal area across the Yangsan fault line. Comparing this gravity field interpretation with other existent geologic and geophysical survey data (e.g. LiDAR, trenching, electric resistivity measurements), It is concluded that (1) the prominent gravity difference is caused by the density difference of about 0.1 g/㎤ between the Bulguksa Granite in the west and the Cretaceous Sandstone in the east side, (2) the fault core is elongated vertically into a depth of about 2,000 meters and extended horizontally 3,000 meters to the NNE direction from Naengsuri area. Our results present that the gravity field method is a very effective tool to estimate a three -dimensional image of the active fault core.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.09a
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• pp.37-42
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• 2005

Remote seismic tomography is regarded as one of the most valuable geophysical technique for the estimation of the rock mass classification in the tunnel area where hard data information such as drill logs are absent. But the results of rock mass classification based on the remote seismic tomography tend to be overestimated in practice. In this study, we propose the effective method to implement the seismic reference velocity ratio based on semblance for the improvement of rock mass classification. Also, to verify its feasibility, proposed technique was tested by using the real field data.