• The Journal of Engineering Geology
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• v.12 no.3
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• pp.319-332
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• 2002

This study is focused on the characterization of an effective hydraulic conductivity in each hydrogeologic unit assumed as an equivalent continuum medium in the granitic area. Four boreholes of 3" diameter were installed and a Multi-packer system was facilitated in the selected borehole. Various in-situ tests including the fracture logging, constant injection and fall-off tests, slug and pulse tests were carried out. A hydrogeologic unit was defined into the upper and lower zones based on the variation of fracture properties and hydraulic conductivities. The difference of the result obtained by the various hydraulic tests and the effective characterization techniques on rock mass permeability are also discussed. The effective hydraulic conductivity of the upper unit was measured by two times(5.27E-10 m/s~7.57E-10 m/s) that of the lower unit(2.45E-10 m/s~6.81E-10 m/s)through the constant injection and fall-off tests.

• The Journal of Engineering Geology
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• v.31 no.1
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• pp.83-101
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• 2021

The high-density polyurethane method uses the instantaneous expansion pressure of injected material to stabilize soft ground, allowing reinforcement, restoration, and construction to be carried out in suboptimal ground conditions. Under normal and, even poor conditions, the method is easily applied because the working time is very short. The method is environmentally friendly and results have excellent durability. The purpose of this study was to verify the physical and mechanical properties of high-density polyurethane in the ground. Initial testing of strength, direct shear, and soil environment stability was followed by testing for permeability in order to address environmental concerns. The results of the experiments showed that the internal friction angle was about twice as high and the adhesion was about 2.5 to 3.5 times higher than for dense and hard clay, and that the permeability factor was significantly lower compared with the existing grouting method, within the range of 1.0 × 10-5.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1924-1928
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• 2009

다중패커시스템은 격리된 어느 특정 구간의 지하수를 채수할 수 있으며 그 구간의 온도, 압력 등의 자료를 연속적으로 관측할 수 있어 이를 통해 각 구간별 수리전도도를 구할 수 있다. 심도별 수직적 지하수두는 지상에서 연결 롯드를 통해 압력 측정 센서를 해당 심도까지 내려 롯드에서 설치된 압력 측정용 장비에서 관측할 수 있으며, 다중패커시스템을 이용한 수리시험으로는 양수시험, 순간충격시험, 간섭시험 등이 있는데, 본 논문에서는 순간충격시험을 이용한 결과를 제시하였다. 도출된 구간별 수리전도도를 다중패커시스템을 설치하기 전 나공에서 이중 패커를 이용한 정압주입시험의 결과와 비교하여 보았다. 다중패커시스템을 통해 획득된 심도별 지하수두는 정수두 (hydro-static)상태의 일정한 경향성이 없이, 각 심도에 존재하는 투수성 구조에 영향을 보이고 있음을 알 수 있었으며, 이는 다수의 관측공을 통해 수평 방향의 수리경사를 산출함에 있어 관측공의 심도에 대한 충분한 고려가 있어야 한다고 판단된다. 또한, 다중패커시스템을 이용한 수리시험 결과를 나공 상태에서 이중 패커를 이용한 정압주입시험 결과에 대해 심도별 도출되는 수리전도도가 국지적으로 분포하는 투수성 구조에 영향으로 인해 투수량계수 (transmissivity)로 환산한 유효 투수계수로 비교하여 결정질 암반의 수리 특성으로 제안하는 것이 타당한 것으로 분석되었다.

• Journal of the Korean GEO-environmental Society
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• v.4 no.4
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• pp.45-51
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• 2003

Grouting materials in rock is grouted as vein type along the fault surface by the other way for soil and allow a change of characteristics in rock faults as a result of that. Therefore the deformation characteristics of rock faults after grouting differ as a direction and characteristic of grouted fault and stress condition of field rock. Thereby it must be analyzed the effect for deformation of rock according to characteristics of rock faults and characteristics of grouting materials to accurately evaluate the reinforced effect by grouting. But grouting method used in field until present depends on experience of workers, and inspection for those effects are evaluated by measurement of elastic wave velocity, permeability tests and etc. in field. In this study, it was investigated that the effects for shear characteristics of maximum shear strength, residual shear strength and etc. by comparison and analysis of test results which were worked by direct shear tests of rock faults with changing a type of grouting materials and the grouting depth(t) for average width(a) of fault surface roughness when OPC(Ordinary Portland Cement) and Micro cement was grouted in fault surface of field rock to evaluate characteristicsof the shear deformation for rock fault surface of dam by grouting.

• The Journal of Engineering Geology
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• v.18 no.1
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• pp.7-16
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• 2008

Limestone area have mostly certain geological defects such as the internal cavities due to melting and fractured zone by external pressures. Especially, in case of constructing grand bridge, the treatment of the limestone cavities area having the geological defects is inevitable. In order to reduce foundation settlement and to reinforce the ground in the limestone cavities area, high pressure jet grouting has been carried out as a countermeasure method. Despite the fact that high pressure jet grouting method has already adopted at a lot of limestone cavities area, but the amount of research and technical data on the high pressure jet grouting have not been accumulated properly so for. Therefore this paper intends to investigate the strength characteristics and deformation characteristics for reinforced limestone cavities area by high pressure jet grouting method. In addition, load carrying capacity obtained by static pile load test with load transfer measuring system is analyzed.

• Journal of the Korean Institute of Gas
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• v.19 no.1
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• pp.64-70
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• 2015

In order to evaluate the degree of hydrogen embrittlement of TRIP steels charged with hydrogen according to varying the current density and the charging time under acid and alkaline electrolyte conditions were tested by small punch test. The results of SP test showed that the degree of hydrogen embrittlement at acid electrolyte condition was more effective factor compared to that of alkaline electrolyte condition. Therefore, all of the charging time and the charging current density were at the condition of acid electrolyte appeared as the main factor of the degree of hydrogen embrittlement in the condition of acid electrolyte. But, it was considered that the charging time compared to the charging current density at the condition of alkaline electrolyte was more effective factor to raise the degree of hydrogen embrittlement.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.4
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• pp.396-403
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• 2016

This study is based on the evaluation of a single component injection type adhesive repair material and a new 2 component type used in leakage of underground concrete structures. The studies showed that based on different mix ratio of the 2 component type adhesive sealant comprised of an asphalt main and latex mixture agent the viscosity of the material compound differed significantly. Based on a permeability testing, injection and economic efficiency, and performance, the appropriate ratio was determined to be 6:1 and was proceeded to the KS F 4935 evaluation method. The 2 component type adhesive sealant uses a static mixer and a cartridge type container for the injection procedure and was able to satisfy the evaluation criteria outlined in the KS F 4935 standard.

• Journal of the Korean Geosynthetics Society
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• v.19 no.4
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• pp.11-20
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• 2020

This study introduced the compact grouting method that can be used for improving soft ground and restoring buildings with unequal subsidence. The pump used in the traditional compact grouting method is a system that injects one hole each, which reduces the construction efficiency, and the analog injection method manually manages the construction by field workers, making it difficult to manage consistent quality. Pump and quality control system were developed to solve problems in existing construction. Since field supervisor determines amount of injected materials by using analog equipment and controls manually, it is difficult to manage consistent quality of construction. Therefore, the quality control system was developed in order to solve that problem. The quality control system consists of automatic mixing system of injection materials, multiple simultaneous injection pumps, and injection management monitoring system. Performance of the quality control system was verified through on-site testing, and ground improvement performance was verified through quality testing after testing and testing of the compact grouting method. Therefore, it is expected that the integrated quality control system developed will improve the quality assurance and efficiency and stability of construction at sites where construction and quality verification are difficult.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.288-291
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• 2005

방사성폐기물 처분연구의 일환으로 단열 암반지역의 지하수 유동에 있어서 각 단열조의 투수량계수를 알아보기 위하여 연구지역에 설치된 3기의 시추공에서 초음파 검층, 정압주입시험 및 유동차원 해석을 수행하였다. 단열은 방향성, 틈의 크기 등의 그 분포 특성으로 인해 각 시험구간내의 지하수 유동에 있어서, 유동형태 및 단열투수량계수를 좌우하므로 일반적으로 수리특성에 널리 이용되는 다공성매질의 연속체 개념을 통한 해석의 적용에 신중성을 고려할 필요가 있다.

• 전기의세계
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• v.13 no.3
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• pp.103-107
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• 1964