• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.193-200
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• 1999

Since Broms and Bennermark(1967) suggested the face stability criterion based on laboratory extrusion tests and field observations, the face stability of a tunnel driven in cohesive material has been studied by several authors. And recently, more general solution for the tunnel front is given by Leca and Panet(1988). They adopted a limit state design concept to evaluate the face stability of a shallow tunnel driven into cohesionless material and showed that the calculated upper bound solution represented the actual behavior reasonably well. In this study, two factors are simultaneously considered for assessing tunnel face stability: One is the effective stress acting on the tunnel front calculated by upper bound solution; and the other is the seepage force calculated by numerical analysis under the condition of steady state ground water flow. The model tests were performed to evaluate the seepage force acting on the tunnel front and these results were compared with results of numerical analysis. Consequently, the methodology to evaluate the stability of a tunnel face including limit analysis and seepage analysis is suggested under the condition of steady state ground water flow.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.133-140
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• 2000

Drilling and blasting method for excavating rock mass is generally used in underground construction; but this technique has some shortcomings. For instance, rock mass damage is inevitable during drilling and blasting, and blast-induced vibration frequently causes some problems. Until now, field measurement method is used to predict the overbreak and vibration; but it has many limitations. Therefore, numerical analysis method is needed to overcome such limitations, and to estimate and predict damage and vibration due to tunnel blasting in the design stage. In this study, damage zone of rock mass due to stoping and contour blasting is compared based on standard tunnel blasting pattern, and the propriety of the standard tunnel blasting pattern is estimated. Then, blasting pattern is optimized so that the damage zone due to sloping blasting with reduced charge is consistent with that due to contour blasting.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.504-511
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• 2000

Geotube is a tube made of permeable but soil-tight geotextile, hydraulically filled with soil include dredged sand and mud, which has been successfully applied in hydraulic and coastal engineering projects. This method is getting popular and used a lot in the advanced countries of the world because of economical, useful, and enable to store and isolate contaminated materials as obtained by harbor dredging. Laboratory and pilot scale in-situ tests were performed to determine the design methodology and construction procedures. From the results of laboratory and in-situ model tests, the retention ratio of solid particle is minimum 86% and minimum permeability and tensile strength of geotextile is ${\alpha}$${\times}$10$\^$-2/ and 20 t/m, respectively. Also, based on the environmental model test results, it can be concluded that this method does meet the Korean EPA standards.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.705-707
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• 2005

For the development of geothermal energy, many different kind of geoscientific data including both surface geological data and underground geomechanical data, are acquired. Integration of such data itself for better understanding of underground condition is not a simple process due to complexity of the data, i.e. mixture of 20 and 3D data, mixture of geological data, geochemical data, geomechanical data and hydrogeological data. This paper reports a preliminary suggestion of GIS modeling for such specific purpose. Data used for GIS modeling mainly came from British case studies. The modeling is much more focused on the design of database for 3D underground geotechnical data in this study.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.473-485
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• 2010

Lightweight materials using in-situ clay soil contain large amounts of fine grain and cement for increasing the strength, lighter weight to increase liquidity for the foam and the bulk of the material is conducted by the water. Domestic cases, Light weight soil to improve cementation and lightness using demountable mixing device is defined Smartsoil. Typical features are their self-leveling, self-compaction, folwability. By adjusting the amount of cement, the strength can be controlled artificially. And re-excavation is easy. In this paper, pre-loading method using the road due to the displacement of adjacent structures under construction as an alternative SmartSoil introduces the design and construction practices. Is to discuss and improve.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.605-614
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• 2010

In this paper, the initial behavior of transmission tower was analyzed. This tower was firstly constructed by rock anchor foundation in domestic 154 kV transmission line and wireless real-time monitoring system was installed to obtain the measured data for analysis of the structure behavior. For this purpose, 16 strain gauges was installed in anchors of foundation and strain gauges, clinometers, anemoscope and settlement sensors was installed at superstructure. As the results, the main factor which influence the behavior of superstructure is wind velocity, wind direction, rainfall and temperature change. Especially, the uplift load at stub of transmission structure revealed about 35.4 percentages of design load. Hereafter the long term stability will be analyzed.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.144-169
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• 2010

In 2002, property loss caused by failure or leakage of existing river levee structures was about 1.8 trillion in Korean Won, and furthermore in which damages of river structures are getting more severe due to characteristics of extremely extraordinary rain such as torrential rain in the locality or guerrilla heavy rain. In this regards, this paper collects and analyzes those damage records and costs for repair by statistic method, and moreover categorizes the causes of failure, erosion and overtopping of levee structures in large and small scale rivers threatened frequently by typhoon and heavy rainfall. It is believed that the results from the analyses can be used as a basic source in developing criteria of standards for design, construction, maintenance and inspection(or diagnosis) of hydraulic structures such as levee and drain conduit.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.951-954
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• 2010

There are lots of soft ground improvement methods which is consist of different materials. In the analysis and design, composite ground method is usually regarded. Composite ground method considers the area replacement ratio as a key parameter to combine the physical and mechanical characteristics of tow different material. In this study, using composite material consist of three different materials which have different diameters, series of specific gravity test were performed according to KS F 2308, to investigate the applicability of composite ground method. As a result, it is found that composite material which is consist of fine grained soil and granular soil has a high applicability of composite ground method. This result means that, in estimating of ground properties of composite material which is consist of similar fine grained material such as cement mixing etc., composite ground method has a less applicability.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.10a
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• pp.490-496
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• 2006

In order to design accurately plastic board drain (PBB) method, it is important to determine the equivalent circle of PBD. In this paper, a series of numerical analyses on soft ground improved by PBD were carried out, in order to investigate the resonable equivalent circle of PBD considering consolidation behavior of improved soft ground by PBD. The applicability of numerical analyses, in which an elasto-viscoplastic three-dimensional consolidation finite element method was applied, could be confirmed comparing with results of a series of model tests on consolidation behaviors of soft ground improved by PBD. And, through the results of the numerical analyses, consolidation behaviors of soft ground during consolidation was elucidated, together with the equivalent circle of PBD considering consolidation behaviors.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.10a
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• pp.23-34
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• 2006

In a oo dam at oo city of Gyeongbuk, severe damages have been occurred on lower part of dam due to heavy rainfall for several years. This caused significant impediment for maintaining its original function. This is considered as an excellent case for overall improvement of stability of dam system through successful investigation and construction work. This paper present comprehensive specifications that are generalized and used for securing stability of dams by quoting this example.