• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.1
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• pp.109-116
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• 2010

The Water glass grouting method has been applied frequently to penetration grouting in practice, but some problems, such as decrease of durability with the elapsed time and environmentally adverse effect, are raised recently. Hence, the Earth Natural Grouting method which uses micro cement and inorganic material is developed to overcomes those problems of the water glass grouting method, and is aimed for extensive ground injection bound. Volumetric strain test, syneresis test, unconfined compression test, triaxial permeability test, in-situ permeability test and heavy metal analysis were conducted to verify application of the ENG. As the result of tests, volumetric strain, syneresis and unconfined strength of the ENG were superior to those of the Water Glass SGR and ENG was proved to be impermeable. Also it is expected that the ENG would not have an effect on environmental pollution.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.106-109
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• 2004

지표하부 상층 오염지하수의 침투로 인한 암반 지하수의 오염을 방지하기 위하여 지하수 개발과정에서 반드시 지표하부 지하수 오염방지를 이행하도록 지하수법에 규정하고 있다. 널리 알려진 지표하부 오염방지 공법으로서는 팩카그라우팅 공법(packer Grouting Method), 트레미공법(Tremie Method)과 브레든 헤드 공법(Bradenhead Method)이 있다. 그러나, 현재 대다수의 지하수 개발 현장에서는 단순히 강관을 굴착공에 억지박음함으로써 지표하부 오염방지에 가름하는 사례가 다반사이며 깊은 심도의 경우에도 종래 공법으로는 한계를 가질 수밖에 없는 실정이었다. 따라서, 본 연구에서는 차폐 팩카(Protection Packer)를 이용하여 고, 저심도의 어느 지하수 심정에서나 용이하게 역주입 상향그라우팅이 가능한 여건이 될 수 있도록 시공 사례를 통해 연구를 수행하였다.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.10b
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• pp.44-58
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• 2001

FRP(Fiberglass Reinforced Plastic)관을 이용한 사면보강은 천공 후 그라우트재에 압력을 가하여 그라우트재의 천공홀 충전뿐만 아니라 지반으로의 침투주입 효과를 일으켜, 전체적인 보강력 증대를 기대하는 공법이다. 이런 특성을 설계에 반영하기 위해서는 구조재료인 FRP관 자체에 의한 지반보강효과 뿐만 아니라 그라우팅에 따른 지반강도의 증진효과를 정량적으로 평가하는 것이 선행되어야 하나 아직까지는 이에 대한 연구가 부족한 실정이다. 따라서 대상지반을 토사와 암반사면으로 구분하여 각각의 보강효과를 확인하고자 현장시험 및 수치해석을 실시하였으며, 이로부터 지반종류에 따른 보강특성과 합리적인 설계를 위한 설계인자를 추출하고자 하였다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.1
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• pp.3-11
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• 2003

Face stability of a tunnel is a main concern during tunnel excavation. However, there has been only a few studies on this problem while a lot of researches on the support systems have been carried out. In addition, when tunneling is performed below the groundwater level, the groundwater flows into the tunnel so that the seepage forces generated on the tunnel face might give rise to a serious potential for the face instability. In this study, the face stability was evaluated by simultaneously considering two factors: one is the effective stress calculated by upper bound theorem; the other is the seepage forces acting on the tunnel face obtained by numerical analysis under the condition of steady-state groundwater flow. Tunneling in difficult geological conditions often requires auxiliary techniques to guarantee safe tunnel excavations and/or to prevent damage to structures and services around the tunnel. The steel pipe-reinforced multistep grouting has been recently applied to tunnel sites in Korea. Face stability of a tunnel with the steel pipe-reinforced multistep grouting was also analyzed in this study.

• Journal of the Korean GEO-environmental Society
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• v.24 no.1
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• pp.15-23
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• 2023

The grouting method is a method of construction for the purpose of waterproofing and reinforcing soft ground. When grout is injected into the ground, there are various types of penetration and diffusion of grout depending on the shape of the ground, the size of soil, the porosity, and the presence or absence of groundwater. the current situation. Therefore, in this study, to investigate the penetration performance of the grouting to conductive material, laboratory tests were performed on the addition of the conductive material. In the injection test, 0%, 3%, and 5% of the mixed water were added as conductive materials to the grout, and the original ground condition was composed of various types of ground composed of gravel and silica sand. Conductive grout is injected by pressure into the model ground using a dedicated injection device, and the injection time (t), pressure (p), flow rate (v) and injection amount (q) are measured, and the hardened body injected in the model ground is collected. Penetration performance was evaluated. In the results of the grout injection experiment, the amount of conductive material used and the grout injection rate showed an inverse relationship, and it was confirmed that the penetration pattern was changed according to the size of the soil particles in the model ground. The grout containing the conductive material has relatively good penetration into the ground and excellent strength and durability of the hardened body, so it was judged that it could be used as an additive for measuring the penetration range of the grout.

• Journal of the Korean GEO-environmental Society
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• v.3 no.4
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• pp.67-79
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• 2002

The purpose of this study is to present criteria of selection of optimum grout materials through analyzing the limitation of permeability of each materials(MSG-N, OPC), in various ground conditions by comparing presentation of strength and permeability of MSG method and LW method(or SGR method). To do that, physical and chemical characteristics of grout materials were analyzed and compressive tests of homogel, mixed coagulation materials and hardening materials in certain mixing ratio, and of milk paste. In addition, permeability tests for each ground soil, each injection pressure, and each materials in combined stratum were performed with massive chamber. The results of tests showed that ultra fine grout materials like grout of MSG is necessary to construct effective grouting in sand and silty sand ground. Also, it is expected to become chemical grouting guide data to layout construction engineers because presented proper injection pressure by kind of object ground in case using ultra-fine grout material.

• Proceedings of the KSEEG Conference
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• 2003.04a
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• pp.265-268
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• 2003

댐(dam)의 기초지반에 시공되는 그라우트 커텐(grout curtain)은 댐 축조 후 기초지반을 통한 침투류를 차단하기 위하여 시행되며, 콘크리트 댐, 흙 댐, 사력 댐 등의 공학적 차이에 따라서 그 시공 위치 및 심도, 폭 등이 다르게 적용된다. 그라우트 커텐(grout curtain)의 설계ㆍ시공 요소는 기초지반의 투수성, 댐 내의 수심, 제체 성토재료의 투수성, 그라우트 커텐의 투수성 등에 의하여 결정되며, 설계 시공 요소들은 그라우팅 커텐의 길이, 폭, 투수도 등이다. (중략)

• Geophysics and Geophysical Exploration
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• v.13 no.1
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• pp.69-79
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• 2010

In order to reduce leakage from a reservoir, a large amount of cement milk (grout) was injected from boreholes drilled around the shores of the reservoir, and monitored to establish the infiltration of cement milk into the bedrock under the reservoir. From laboratory tests using rock core samples, it was revealed that the resistivity of cement milk is much lower than that of the groundwater at this location. Therefore, it was expected that the resistivity of the zones filled with cement milk would be significantly reduced. Geophysical surveys are expected to be suitable methods to check the effectiveness of grouting in improving the water-retaining performance of a reservoir. DC electrical surveys (seven in total) and two Controlled Source Audio-frequency Magneto-Telluric (CSAMT) surveys were conducted along survey lines in the reservoir to monitor the infiltration of cement milk during the grouting. Extremely low resistivity zones ($10\;{\Omega}m$ or less) were observed in resistivity sections obtained by 2D inversion. The zones are inferred to be fractured zones filled with cement milk. In sections showing the rate of change of resistivity, three zones that showed significant change showed gradual expansion to deeper parts as the grouting progressed. These zones correspond to highly permeable zones detected by Lugeon tests at grout boreholes. We have confirmed that it is possible to measure the resistivity change by DC electrical and CSAMT surveys from the surface of the reservoir. It seems that such monitoring results could be reflected in future grouting plans.

• Journal of the Korean Geotechnical Society
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• v.33 no.10
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• pp.49-58
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• 2017

Grouting for soil improvement has generally been applied to the depth over water table. Recently, it is needed to develop the grouting technique for soils under greater static water pressure or greater overburden pressure in constructions such as deep excavation or harbour deepening. In this study, a laboratory apparatus was developed to control the injection pressure, load pressure, and hydrostatic pressure. A series of experiments were performed with various degrees of hydrostatic pressure using the developed equipment. As a result, injected volume increase as injection pressure increase, while the volume significantly decreased under hydrostatic pressure. Larger volume of grout bulb was shown in soils with larger granular and pore size based on the comparison result of volume changes with respect to the amount of grouting injection.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.83-83
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• 2023

댐의 침투수량은 준공이후 댐 안전성 확보를 나타내는 지표 중의 하나이며, 유지관리를 위해 침투수량 측정을 실시하여 관리를 하고 있다. 댐 타입별로 침투수량에 대한 허용치와 관리기준치는 다르지만, 기본적으로 댐에서 발생되는 침투수량은 측정범위를 넘지 않도록 관리를 하고 있다. 댐의 침투수량 측정은 댐 하류에 누수집수벽을 설치하고 댐에서 발생되는 침투수량을 집수한 후 삼각위어를 통하여 침투수량을 측정하고 있다. 이러한 침투수량 측정은 대부분의 댐에서 실시간으로 자동측정하고 있지만, 경우에 따라 미계측 구간이 발생되어 댐 유지관리 측면에서 미계측에 대한 원인분석이 필요한 실정이다. 일반적으로 침투수량의 미계측 원인은 계측기기, 삼각위어, 누수집수벽, 기초지반 등 다양한 원인이 있지만 명확한 원인을 찾기는 어려움이 많다. 특히, 댐 침투수량의 경우 지하수위, 댐 표면 우수, 침투수가 같이 측정되기 때문에 원인분석을 위해서는 다양한 검토가 필요하다. 본 연구의 표면차수벽형석괴댐은 누수집수벽을 통하여 침투수량을 측정하고 있으나, 일부 구간 미계측 부분이 발생하여 기초지반, 댐체 하류사면, 여수로와 댐체 접합부를 통한 누수를 원인으로 추정하였다. 이를 조사하기 위하여 전기비저항 탐사, 시추조사, 수압시험, 지하수위 측정 결과를 이용하여 누수발생 추정위치를 찾고, 침투수량이 미계측되는 원인을 분석하고자 하였다. 전기비저항 탐사는 여수로 접합부, 누수집수벽 상·하류 구간을 선정하여 측정한 결과 상·하류 저비저항대가 존재하는 구간을 추정할 수 있었다. 수압시험 결과 기초암반은 2.3 ~ 21.3 Lu(3.65×10^-5 ~ 3.65×10^-4 cm/sec)의 범위로 누수 가능성이 있는 높은 투수성을 갖는 부분을 확인할 수 있었다. 전기비저항 탐사, 수압시험, 지하수위 측정을 통해 누수집수벽 기초지반 누수발생 원인분석 결과 누수집수벽 기초암반을 통한 누수로 누수집수벽에 댐체를 통한 침투수량이 저류되지 못하는 현상이 발생하기 때문인 것으로 판단되었다. 침투수량계의 정상화를 위해서는 조사를 통해 확인된 누수집수벽 기초암반 누수구간의 그라우팅 보수보강이 필요함을 확인하였다.