• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.297-304
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• 2002

This study is about penetrability of Micro Cement(MC) used for ground improvement. In this study, the characteristics of chemical grouting such as solidification, penetrability were analyzed experimentally by changing permeability of ground, grain size and relative density of grout material. For evaluating applicability of grout material, solidification test and penetrability test were performed. From the results of the tests, effective solidification ratio and penetrability ratio of MC was each 75%, 86% to be excellent when ground permeability was in the range of 10$^{-2}$ and 10$^{-4}$ cm/sec. Otherwise, those of Ordinary Portland Cement(OPC) were both lower than 50% to be poor. When penetrability of grout material is needed for improvement of dam foundation and soft ground, application of MC Is much superior to that of the other materials. The results of the grouting tests in the water flowing ground show that solidification effect of long gel-time grout material is excellent as injection pressure increases when groundwater velocity is relatively low. But when groundwater velocity is relatively high, solidification effect of long gel-time grout material is very poor because most grout materials are outflowed. Therefore, as groundwater velocity is high, effective solidification ratio of long gel-time grout material is better than that of short gel-time grout material, also penetration distance of long gel-time grout material is longer than that of short gel-time grout material.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.414-423
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• 2006

Many construction projects adopt grouting technology to prevent the leakage of groundwater or to improve the shear strength of the ground. Recognition as a feasible field procedure dates back to 1925, Since then, developments and field use have increased rapidly. According to improvement of grout materials, theoretical study on grout penetration characteristics is demanded. Fluid of grout always tends to flow from higher hydraulic potential to lower and the motion of grout is also a function of formation permeability. Viscosity of grout is changed by chemical action while grout moves through pores. Due to the increment of viscosity, permeability is decreased. Permeability is also reduced by grout particle deposits to the soil aggregates. In this thesis, characteristics of new cement grout material that is developed recently is studied: injectable volume of new grout material is tested in two different sizes of sands, and the method to calculate injectable volume of grout is suggested with consideration of change in viscosity and clogging phenomena. The calculated values are compared with injection test results. Viscosity of new grout material is found to be an exponential function of time. And lumped parameter $\theta$ of new grout material to be used for assessing deposition characteristics is estimated by comparing deposit theory with injection test results considering different soil types and different injection pressure.

• 한국지열·수열에너지학회논문집
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• 제7권1호
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• pp.10-16
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• 2011

Performance of ground-source heat pumps (GSHPs) is mainly affected by ground heat exchangers which makes up more than 40% of construction cost. Exact construction and grout as backfill are important, because it is difficult to repair after being installed. As grout materials, bentonite grout material and cement material are used In this paper, thermal conductivity according to mix proportion of cement grout has been experimentally studied. Some variables were set to evaluate thermal conductivities according to change in cement content, unit water ratio, mass per volume of fresh mortar, and aggregate types. From the experimental analysis, high performance cement grout has been proposed.

• Nuclear Engineering and Technology
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• 제43권5호
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• pp.459-468
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• 2011

The current solution to the problem of using cementitious material for sealing purposes in a final radioactive waste repository is to develop a low-pH cement grout. In this study, the material properties of a low-pH cement grout based on a recipe used at ONKALO are investigated by considering such factors as pH variation, compressive strength, dynamic modulus, and hydraulic conductivity by using silica fume and micro-cement. From the pH measurements of the hardened cement grout, the required pH (< pH 11) is obtained after 130 days of curing. Although the engineering properties of the low-pH cement grout used in this study are inferior to those of conventional high-pH cement grout, the utilization of silica fume and micro-cement effectively meets the long-term environmental and durability requirements for cement grout in a radioactive waste repository.

• 한국지반환경공학회 논문집
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• 제11권12호
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• pp.13-18
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• 2010

본 연구는 최근 개발된 실리카졸 그라우팅재의 환경영향성 및 내구성을 규명한 것으로써 연구에 사용된 그라우트재는 3차원 겔 형성재인 실리카졸 그라우팅제와 규산나트륨 그라우팅제에 대한 공학적 특성을 비교하기 위하여 전자현미경 촬영, 내화학성시험, 용탈시험, 투수시험 등을 통해 친환경성과 내구성을 규명하고자 하였다. 전자현미경 촬영 결과 실리카졸 그라우팅제의 표면 및 내부조직이 규산나트륨보다 치밀함을 확인할 수 있었다. 용탈시험 결과 용탈되는 원소의 총량도 극히 작아 친환경적인 재료임을 입증되어 지반주입재로써 적용성을 확인하였다. 투수시험 결과 실리카졸이 차수성면에서 현장에 적용하는데 무리가 없다고 판단되어 차수성을 요구하는 현장에 적용이 가능하다고 판단된다.

• 한국지반공학회논문집
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• 제23권4호
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• pp.5-13
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• 2007

1925년 이후 지반개량공법은 많은 발전을 거듭해 왔으며, 많은 건설현장에서 차수의 목적 또는 지반강도 증진의 목적 등으로 그라우팅이 적용되어왔다. 지반개량공법의 발전과 더불어 그라우트재의 종류 또한 그 수가 증가되었으며, 그라우트재의 침투특성과 관련된 이론적인 연구의 필요성이 요구되었다. 전수두차에 의해 그라우트재의 흐름이 발생되며, 그라우트재의 이동은 지반의 투수계수의 영향을 받는다. 그라우트재가 지반의 간극을 지날 때, 그라우트재의 화학반응에 의해 점도가 변화되며, 따라서 점도 증가로 인하여 투수계수는 감소하게 된다. 또한 현탁액형의 그라우트재의 경우 그라우트재 입자에 의한 지반 간극의 폐색으로 투수계수가 감소하게 된다. 본 논문에서는 새로 개발된 그라우트재의 물리적-화학적 특성을 연구하고, 입경이 다른 두 종류의 모형지반에서 실시된 신개발 그라우트재의 주입실험 결과와 비교하여 점도변화와 폐색현상을 고려한 그라우트재의 침투 가능성을 이론적으로 제시하고자 한다. 측정된 신개발 그라우트재의 점도는 시간의 지수함수 형태를 보였으며, 실험결과와 비교하여 폐색현상과 관련된 계수 $\delta$를 추정하였다. 그라우트재의 점도 변화는 시간에 따른 주입량에 많은 영향을 주는 것으로 나타났으며, 간극의 크기가 작은 지반에서 주입실험을 실시한 결과 폐색현상의 영향으로 주입량이 현저하게 감소되는 것으로 나타났다.

• Geomechanics and Engineering
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• 제19권4호
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• pp.361-368
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• 2019

This study aims to evaluate the applicability of a grout material that is mixed with carbon fiber, biogrout, ground granulated blast furnace slag (GGBS) powder and cement. Uniaxial compressive strength tests were performed on homo-gel samples at days of 1, 3, 7, 14 and 28. In addition, the variation of permeability with the mixing ratios was measured. Based on the uniaxial compressive strength test, it was confirmed that the uniaxial compressive strength increased by 1.2times when carbon fiber increased by 1%. In addition, as a result of the permeability test, it was found that when the GGBS increased by 20%, the permeability coefficient decreased by about 1.5times. Therefore, the developed grout material can be used as a cutoff grouting material in the field due to its strength and cut-off effect.

• 한국지반환경공학회 논문집
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• 제13권6호
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• pp.41-50
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• 2012

일반적인 그라우팅 재료는 물속에서 재료 분리가 발생하여 수중 그라우팅 작업시 시공 품질 확보가 매우 어렵다. 최근에는 다양한 혼화제를 첨가하여 수중에서 재료분리가 발생하지 않는 수중 불분리성의 그라우팅 재료들이 개발되고 있다. 본 연구에서는 계면활성제계 개질제를 이용하여 수중에서 재료분리가 발생하지 않으면서도 유동성을 충분히 갖는 점탄성 그라우트재를 개발하고 실내시험을 통해 해수 및 담수에 수중 불분리성 그라우팅 재료와 일반 그라우팅 재료를 시공하였을 때의 공학적 특성을 분석하였다. 본 연구에서 개발한 수중 불분리성 그라우팅 재료는 일반 그라우트재와 비교하여 해수와 담수 상태에서 충분한 강도가 발휘되었으며 수중에서 재료 분리가 발생하지 않아 수중에서도 좋은 시공 품질을 확보할 수 있을 것으로 평가되었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.197-198
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• 2023

This study was conducted as part of research and development of high-strength grout. Accordingly, dolomite aggregate was used as a filler incorporated into the high-strength grout. Dolomite aggregate has a disadvantage of increasing the viscosity of the grout due to higher generation of fine powder than other aggregates. Accordingly, in this experiment, it was confirmed that the viscosity, flow time, and flow of high-strength grout change according to the volume composition ratio of dolomite aggregate and cement-based material. All experiments were conducted based on the Korean Industrial Standard KS F 4044, and the mixing factor was applied according to the composition ratio of the binder and the filler. In the experiment, the amount of fine powder contained in the dolomite aggregate rather than the silica sand used in the past is grasped, and after mixing with the grout accordingly, the mixture is proceeded to measure the viscosity in an unhardened state. In addition, the flow and flow time of the grout are evaluated according to the viscosity. As a result of the experiment, it was confirmed that the viscosity and flow time decreased and the flow increased as the volume composition ratio of the dolomite aggregate to the cement-based material increased.

• 한국지반공학회논문집
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• 제23권11호
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• pp.49-58
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• 2007

침투그라우팅시 미세입자의 이동 메카니즘과 미세입자들의 간극 충진 후 강도증가 상태를 파악하기 위해 PFC3D를 이용한 수치해석을 수행하였다. 해석을 위하여 업스케일링 기법을 이용하였으며 연구를 통해 다음과 같은 사실들이 관찰되었다. 첫째, 토층 입자에 대한 그라우팅 미세 입자의 상대적 크기가 0.05배에서 0.25배로 증가하면서 입자의 이동이 제한을 받게 된다. 특히, 0.20배 또는 0.25배의 그라우팅 미세입자의 경우, 토층 입자들 간의 공극이 하나 또는 다수의 미세입자들에 의해 막히기 때문에 미세입자의 이동이 거의 없다. 또한 0.05배와 0.10배의 경우, 입자의 이동량이 거의 유사하므로 입자 크기가 감소되어도 그라우팅 효과의 증진은 한계가 있다. 둘째, 침투그라우팅 전과 후의 수치시료에 대한 물성 실험을 한 결과 점착력과 마찰계수가 증가함이 확인되었다.