• 한국안전학회지
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• 제23권4호
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• pp.79-84
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• 2008

Auto injector grouting method as low pressure injected by using epoxy and Boyle's law is very excellent method in economical efficiency and construction work because injected process can be dealt with collectively. For estimation of filling capacity purpose of this study compared the Auto injector method with the piston injector method. In this study, the tests allow for width of crack, injected angle of epoxy resin and injected method were performed using concrete block specimen making artificial crack. The results of test, tilling et1iciency of epoxy by Auto Injector grouting method verify to better than the piston injector method and uniaxial strength increased about 11% than standard specimen.

• 터널과지하공간
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• 제6권4호
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• pp.298-305
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• 1996

Grouting technique is frequently used where a tunnel structure is passing through the shallow overburden area or where the thickness of hard rock above the tunnel is rather thin. However, engineering background on design process of the grout reinforcement does not seem to be fully understood until now. Mechanics of composite material is, therefore, introduced in this study to investigate the orthotropic material properties of the composites containing soil(or rock) and grouting material. These orthotropic material properties can be used to represent the reinfocement effects quantitatively. The model developed in this study is next applied to a typical tunnel structure and the grouting effect is analyzed numerically. The idea used in this study can be expanded to a situation where a pipe roofing or a forepoling technique is adopted and a simplified design procedure, similar to the model model introduced in this study, can be developed.

• Geomechanics and Engineering
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• 제8권1호
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• pp.113-132
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• 2015

In this study, lime (L), silica fume (SF), and lime-silica fume (L-SF) mix have been used for stabilizing and considering their effects on the soft clay soil. The improvement technique adopted in this study includes improving the behaviour, of a square footing over soft clay through grouting the clay with a slurry of lime-silica fume before and after installation of the footing. A grey-colored densified silica fume is used. Three percentages are used for lime (2%, 4% and 6%) and three percentages are used for silica fume (2.5%, 5%, 10%) and the optimum percentage of silica fume is mixed with the percentages of lime. Several tests are made to investigate the soil behaviour after adding the limeand silica fume. For grouting the soft clay underneath and around the footing, a 60 ml needle was used as a liquid tank of the lime-silica fume mix. Slurried silica fume typically contains 40 to 60% silica fume by mass. Four categories were studied to stabilize soft clay before and after footing construction and for each category, the effectiveness of grouting was investigated; the effect of injection hole spacing and depth of grout was investigated too. It was found that when the soft clay underneath or around a footing is injected by a slurry of lime-silica fume, an increase in the bearing capacity in the range of (6.58-88)% is obtained. The footing bearing capacity increases with increase of depth of grouting holes around the footing area due to increase in L-SF grout. The grouting near the footing to a distance of 0.5 B is more effective than grouting at a distance of 1.0 B due to shape of shear failure of soft clay around the footing.

• Geomechanics and Engineering
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• 제23권2호
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• pp.151-163
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• 2020

Grouting method is an effective way of reinforcing cracked rock masses and plugging water gushing. Current grouting diffusion models are generally developed for horizontal cracks, which is contradictory to the fact that the crack generally occurs in rock masses with irregular spatial distribution characteristics in real underground environments. To solve this problem, this study selected a cement-sodium silicate slurry (C-S slurry) generally used in engineering as a fast-curing grouting material and regarded the C-S slurry as a Bingham fluid with time-varying viscosity for analysis. Based on the theory of fluid mechanics, and by simultaneously considering the deadweight of slurry and characteristics of non-uniform spatial distribution of viscosity of fast-curing grouts, a theoretical model of slurry diffusion in an oblique crack in rock masses at constant grouting rate was established. Moreover, the viscosity and pressure distribution equations in the slurry diffusion zone were deduced, thus quantifying the relationship between grouting pressure, grouting time, and slurry diffusion distance. On this basis, by using a 3-d finite element program in multi-field coupled software Comsol, the numerical simulation results were compared with theoretical calculation values, further verifying the effectiveness of the theoretical model. In addition, through the analysis of two engineering case studies, the theoretical calculations and measured slurry diffusion radius were compared, to evaluate the application effects of the model in engineering practice. Finally, by using the established theoretical model, the influence of cracking in rock masses on the diffusion characteristics of slurry was analysed. The results demonstrate that the inclination angle of the crack in rock masses and azimuth angle of slurry diffusion affect slurry diffusion characteristics. More attention should be paid to the actual grouting process. The results can provide references for determining grouting parameters of fast-curing grouts in engineering practice.

• 한국터널지하공간학회 논문집
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• 제20권6호
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• pp.989-1002
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• 2018

암반 내 그라우팅은 불연속면 내부에 시멘트 그라우트재를 주입하여 주변지반을 강화하는 목적으로 사용된다. 현장에서 다상의 그라우트재의 주입 시 거동특성 및 주입경로인 3차원 절리면의 형태가 사전파악되지 않으므로 정량적인 설계가 어려운 분야중 하나이다. 따라서 현장에서의 그라우트 주입 거동특성을 나타내는 GIN (Grouting Intensity Number) 지표를 이용하여 주입 모니터링을 통해 적절한 시공관리를 수행하는 것이 최적이 방안이다. 본 논문에서는 그라우팅 주입 시 절리면의 거칠기 등급과 물시멘트(W/C)비에 따라 발생하는 압력의 손실을 전산유동해석을 수행하여 조사하였다. 절리면이 거칠수록 그리고 물시멘트비가 높을수록 주입 시 마찰저항은 크게 발생하였으며 해당 결과를 각 조건별 상관식으로 정리하였다.

• 한국지반공학회논문집
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• 제38권2호
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• pp.15-27
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• 2022

암반 그라우팅은 시설물 지반의 안정성을 향상시키는 보강 및 재해방지 대책으로서의 적용성이 날로 증가하고 있으나, 현장에서의 그라우팅은 대부분 경험에 의존하는 바 가이드라인으로 사용할 수 있는 주요 계획인자에 대한 최소 기준값이 필요한 실정이다. 본 연구에서는 암반 그라우팅 계획에 있어 중요한 인자인 주입조건(물-시멘트비, 주입압, 단위 시멘트 주입량)과 그라우팅 효과(변형계수와 투수성)에 대한 기준값을 제시하였다. 제시된 기준값들은 국내외 수압파쇄시험 및 암반 투수시험 자료, 국내외 17개 현장의 그라우팅 시험시공 자료, 그리고 국내외 기준 및 연구를 분석한 결과이다. 또한 그라우팅 효과를 제고하기 위한 안정한 주입재의 조건에 부합하도록 국내의 높은 물-시멘트비는 조정되어야 하며, 조정된 물-시멘트비 적용에 따른 기준값 조정방안도 살펴보았다. 본 연구의 결과 역시 경험의존적인 측면이 있지만, 현재 기준 보다 합리적인 그라우팅 계획의 기준을 제시를 위한 향후 세부연구의 기초자료로 활용할 수 있을 것이다.

• 한국터널지하공간학회 논문집
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• 제20권2호
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• pp.375-392
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• 2018

쉴드 TBM 공법은 터널의 변형을 최소화할 수 있는 공법으로 도심지 얕은 터널 공사에 적합한 공법이다. 하지만 이러한 쉴드 TBM 공법의 장점에도 불구하고 침하가 발생하며, 토피가 낮은 지반에서 쉴드 TBM 굴진 중 침하에 대한 대책은 여전히 주요 쟁점사항 중 하나로 남아있다. 쉴드 TBM 공법에서 테일 보이드는 불가피하게 발생하는 공간으로 테일 보이드의 변형은 침하의 주요 원인이 된다. 이러한 테일 보이드의 변형은 뒤채움 그라우팅을 통해 제어되며, 이를 통해 침하를 억제하거나 회복시킬 수 있다고 여겨지고 있다. 하지만 실제 뒤채움 그라우팅을 통한 침하 회복은 기대하기 어려우며 특히 사질토에서 두드러진다. 이는 뒤채움 그라우팅과 사질토 지반 사이의 상호작용에 기인한 것으로 유추할 수 있다. 본 연구에서는 3차원 수치해석을 통해 사질토 지반에서 뒤채움 그라우팅이 지반거동에 미치는 영향을 파악하고자 하였다. 해석결과, 뒤채움 그라우팅은 침하증가율을 감소시켜 쉴드 TBM 굴진으로 인하 침하를 감소시키나, 그라우팅 이전에 발생한 침하를 회복시키지는 못하는 것으로 나타났다. 이는 뒤채움 그라우팅으로 인해 감소된 체적손실의 지표침하 감소 효과를 지반 내 체적변형이 상쇄하기 때문인 것으로 나타났다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.1340-1347
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• 2006

During excavation in seocheon tunnel, sudden groundwater inundation occurred in complex hydro-geological environments prevailing in underground tunnel. Large volumes of groundwater flowed into tunnel at STA 54km600. The authors have provided a comprehensive background to hydro-mechanics of groundwater with a geological analysis, ground investigation, hydro- mechanical modelling etc. To reinforce tunnel, we have applied the TAS grouting and the steel multi-layer grouting, and comfirmed the effects of reinforcement.

• 한국구조물진단유지관리공학회 논문집
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• 제6권3호
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• pp.211-220
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• 2002

CGS(Compaction Grouting System) is widely used in reinforcement of structural foundation and ground improvement in soft ground. But the effects of ground improvement depending on the type of soil must be studied in order to adopt in various soils (granular soil and cohesive soil). In this study, characteristics of ground improvement (the increase of N value, increase in unit weight, vertical displacement on the ground surface) by CGS method was compared through two cases that were performed in granular and cohesive soil. The results show that the closer to the grout hole, the more increase in N value and this trend appear distinctly in granular soil. Unit weight of ground increase largely near by the grout hole and decrease in far from it independently of the soil type. The vertical displacement on the ground surface appeared in smaller area in case of granular soil than cohesive soil.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2007년도 공동학술대회 논문집
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• pp.101-106
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• 2007

A time-lapse microgravity survey on a newly widen road at Muan, where limestone cavities are developed, for monitoring the change of the subsurface density distribution before and after grouting. Microgravity monitoring is identified as a quick, easy and cost effective. But, it requires strict data acquisition and quality control due to the differences of conditions at measurements. The survey was carried out two times, that is, October 2005 and September 2006. The data were adjusted for reducing the effects due to the different condition of each survey. The processed data acquired in 2005 and 2006 were inverted into the subsurface density distributions. They show the change and development of density structure during the lapsed time, which implies the effects of grouting.