• Computers and Concrete
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• v.7 no.2
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• pp.191-202
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• 2010

A laboratory investigation was conducted to characterize the constitutive property behavior of Cor-Tuf, an ultra-high-performance composite concrete. Mechanical property tests (hydrostatic compression, unconfined compression (UC), triaxial compression (TXC), unconfined direct pull (DP), uniaxial strain, and uniaxial-strain-load/constant-volumetric-strain tests) were performed on specimens prepared from concrete mixtures with and without steel fibers. From the UC and TXC test results, compression failure surfaces were developed for both sets of specimens. Both failure surfaces exhibited a continuous increase in maximum principal stress difference with increasing confining stress. The DP tests results determined the unconfined tensile strengths of the two mixtures. The tensile strength of each mixture was less than the generally assumed tensile strength for conventional strength concrete, which is 10 percent of the unconfined compressive strength. Both concretes behaved similarly, but Cor-Tuf with steel fibers exhibited slightly greater strength with increased confining pressure, and Cor-Tuf without steel fibers displayed slightly greater compressibility.

• Journal of the Korean Geotechnical Society
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• v.22 no.4
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• pp.31-39
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• 2006

An experimental investigation was carried out to evaluate the strength characteristics of low cement ratio soil stabilizer. The low cement ratio soil stabilizer has been developed by the replacement of certain part of cement with by-product pozzolanic materials such as blast furnace slag, fly ash, waste gypsum and by using activator. A series of unconfined compressive strength tests were performed to investigate and obtain high-strength composite soil stabilizer with large amounts of blast furnace slag and fly ash. Test results show that there were better properties when blast furnace slag, fly ash, waste gypsum, and activator were added in proper ratio. The replacement of certain part of cement with by-product pozzolanic materials improved the strength and pore structure properties.

• The Journal of Engineering Geology
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• v.19 no.4
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• pp.483-492
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• 2009

During construction of a tunnel and underground structure, it is very important to acquire accurate information of the rock mass will be excavated. In this study, the drill monitoring method was applied for rapid prediction of geological condition ahead of the tunnel face. Mechanical data(speed, torque and feed pressure) from drilling process using a hydraulic drilling machine were analyzed to assess rock mass characteristics. Rock mass information acquired during excavation from drilling monitoring were compared with results from horizontal boring and tunnel seismic profiling(TSP). As the result, the drilling monitoring method is useful to assess rock mass condition such as geological structures and physical properties ahead of the tunnel face.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.69-83
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• 2001

In order to make use of finished municipal landfill as a construction site, it is necessary to consider environmental and geotechnical aspects for the ground improvement and application of waste landfill. In environmental aspect, methods for management of landfill gas and leachate have to be established, and in geotechnical aspect, it is necessary to investigate available method for constructing structure foundation. In this study, the finished landfill was selected for pilot test. Investigation about the environmental characteristics of the waste landfill was performed to establish the methods far management of landfill gas according to monitoring the gas quantity and to investigate economical efficiency according to utilizing landfill gas. Investigation about cases of utilizing the waste landfill in Korea and abroad as construction site was performed and pilot tests were performed to analyze the improvement effects of methods such as dynamic compaction method and PG pile method available to waste landfill. The results of this study showed that economical profits could be gained by utilizing landfill gas and improved waste landfill, besides, dynamic compaction method was effective in case of improvement depth being shallow, and PG pile method was effective in case of improvement depth being deep.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.524-528
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• 2009

An influence factors for soundness evaluation of river levee include resistibility and embankment for piping of ground consisting embankment in case piping, permeability coefficient of ground, height of embankment, the width of crest, material characteristics of embankment and foundation ground, shape of embankment slope, an influence for penetration of rainfall or river water in case slope stability. In this study, it was operated a feasibility investigation of existing design result, stability evaluation for permeability coefficient use and permeability coefficient change of foundation ground to investigate an influence in line with permeability coefficient change for result of river levee penetration analysis. The evaluation results of influence factors, the permeability coefficient used in design and it was evaluated influence in safety factor of piping. After the evaluation of influence factors, the permeability coefficient used in the design appears with the fact that differs in a design report about same soil, Accordingly, the stability investigation of embankment by application of literature data can affect stability evaluation results by change factors like a permeability coefficient, void ratio. It should be certainly used material properties by a test in soundness evaluation of river levee.

• Geotechnical Engineering
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• v.13 no.1
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• pp.59-74
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• 1997

This paper presents the results of the geotechnical investigation and settlement analysis of a finished waste landfill to find the possibility of the site as a construction area. Also, the variations of the strength of the municipal waste after mixing with the several types of the particulate grouts are investigated. The materials of the grouts used in the experiment are Quick Lime, Portland Cement, Slag Cement and Geocrete Cement. The results of the geotechnical investigation show that the maximum dry unit weight of the waste becomes lower and optimum moisture content higher as the age of the disposed waste is younger and the organic content is higher. The thickness of the predicted differential settlements of the waste fill has large difference from location to location and the unconfined compression strength of the grout mixed waste from the experiment was higher in the order of Geocrete Cement, Slag Cement, Portland Cement and Quick Lime.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.1
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• pp.1-11
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• 2023

In this study, the stability of the room-and-pillar underground method was investigated using numerical analysis method. In-situ geotechnical investigation was conducted, and a supporting pattern was selected based on the geotechnical investigation data. For the supporting pattern, Type-1, 2, 3 were selected for each ground condition. A 3D numerical analysis model was developed for effective simulation as the room-and-pillar underground method consist of a pillar and room. As a review of numerical analysis, it was confirmed that the crown settlement, convergence, shotcrete and rock bolt were all stable in all supporting patterns. As a result of the analysis by the construction stage, it was confirmed that excessive stress was generated in the room when the construction stage of forming pillar. So, precise construction is required during the actual construction stage of the pillar formation.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1999.10a
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• pp.69-72
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• 1999

Now there has been a steady increase in the field of geoenvironmental engineering projects where geotechnical engineering has been combined with environmental concerns. Many of these projects involve some investigation on leachate flume in the waste landfill. In this study, investigation on leachate around the waste landfill was carried out to detect the leachate leaking area. Many techniques such as geophysical, drilling and sampling method were applied. As a result of this investigation, the concentration of leachate and the point of leachate leaking around landfill were analysed.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.1100-1106
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• 2009

A debris flow is known as that flood and landslide of water cause much physical human damages worldwide to complex natural disaster that happen combining and happy event is happening mainly in urgent mountains area in domestic. Because happen about debris flow that happen from each place every year and is drift, mechanism of accumulation definitely make clear and great many damage is not running out. Must grasp actual conditions of priority debris flow to need debris flow prevention countermeasure and lay countermeasure to take away damage by debris flow. Because collecting actual conditions of debris flow that happen by objective investigation methods and accuracy, proposed about investigation calamity investigation method so that can calculate debris flow damage and prepare in subsequentness damage.

• Journal of the Korean Geotechnical Society
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• v.33 no.9
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• pp.35-47
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• 2017

Recently, the 3D image of the geotechnical information has been constructed along with the 3D integrated underground space mapping project. Prior to the visualization of the 3D image of the geotechnical information, it is necessary to analyze and verify the accuracy of the geotechnical information. Previous studies evaluated the precision of collected geotechnical information DB to validate the quality of the collected DB and later studies on the 3D precision were performed to provide the basic data for the 3D integrated underground space map. In this study, practical application methodologies are suggested based on the previous studies to improve the accuracy of the applied geotechnical information and further to improve the reliability of the constructed 3D integrated underground space map.