• Proceedings of the Korean Geotechical Society Conference
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• 2001.10b
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• pp.31-42
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• 2001

다양한 방식으로 제작된 유리섬유 강화 플라스틱관(FRP pipe)의 인장 및 휨강도 시험 결과로부터 제작방식에 따른 FRP관의 강도 특성을 비교 검토하였다. 또한, 사면보강대책으로서 FRP 그라우팅 공법의 현장 적용성을 평가하기 위하여, FRP 그라우팅에 따른 지반강도의 증진효과 및 보강재의 인발저항력을 산정하였다. 이를 위하여, 지반의 상대밀도 및 구속압에 따른 보강재 인발저항력의 변화 및 압력주입에 의한 확공효과 평가를 위하여 실내모형실험이 이루어졌다. 또한, FRP 그라우팅이 시공된 현장에서 공내재하시험, 투수시험, 그리고 시추공전단시험 등을 실시하여 FRP 그라우팅에 의한 지반보강 효과 및 차수효과를 정량적으로 산정하였다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.4
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• pp.349-360
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• 2003

A practical modeling approach has been proposed in this study to better understand the behavior of penetration grouting which is normally applied to the jointed rock masses to increase the bearing capacity and to reduce the ground water flow into the tunnel. Based on Bingham model together with a steady-state flow of the grout, penetration model is simulated in the commercial package called UDEC and, injection pressure as well as joint thickness are found to be the main parameters to determine the range of grout spread. Another numerical model on fracturing grouting is also suggested and, in this case, the tensile strength as well as cohesion of the rock masses are proven to be the major factors to decide the fracturing mechanism of the rock masses. The reinforcement effect of the grout-reinforced rock masses is calculated from the suggested algorithm on orthotropic material model and it is found that the directional stiffness of reinforced rock masses is increased up to 3 to 4 times compared with original jointed rock masses. Future work will be concentrated on the water control around the tunnel by the grout injection and a model test will also be performed to verify the suggested methods developed in this study.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.279-286
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• 2018

The grouting method is to reinforce the ground by injecting the chemical solution for the strengthening of the ground. Cement grouting material has usually used portland cement for centuries ago, but the cement particle size is large and the injection effect is limited. This study analyzes the effect of ultrafine cement grouting in rock ground using 3S-1 grouting in rock ground and ordinary Portland cement (OPC). The results of tests were compared and analyzed from the Lugeon test, bore loading test (P.M.T.), and injection (P-Q) test. The use of ultrafine cement (3S-1) had a higher effect (K, 10-6cm/sec) than OPC. The reinforcement effect of 3S-1 was also confirmed. Ultrafine cement (3S-1) was 4~9 times more injectable than OPC. Therefore, it is more advantageous to use ultrafine cement (3S-1) than OPC.

• Journal of the Korean GEO-environmental Society
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• v.16 no.7
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• pp.35-42
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• 2015

Grouting method has been widely used for the ground improvement and stabilization: mostly to block or control the ground water in the early years and to improve the ground, repair the structure in recent years, ever increasing its use. Despite many advantages so far, the existing grouting method also has some shortcomings including uncertain permeation of grouting with gravity type if the voids between the soil particles are narrow, and problems due to the relaxation of the neighboring ground when injected using injection pressure. As an alternative, a vibration injection method with constant amplitude and frequency has been developed in recent years, with the vibration grouting being reported to have a permeability increasing effect of grout material compared with the positive pressure injection type. Accordingly, the purpose of this study is to investigate the improvement effect of the vibration grouting that applies short-period vibration energy by varying vibration cycle, vibration time and ground conditions to evaluate the strength enhancing effect of grouting materials, expansion effect of grouting body, ground improvement effect of the grouting and the penetration characteristics of the rock joint. The findings of this study show the improved compressive strength of grout, expansion of grouting body and increased penetration rate, according to the vibration compared with non-vibration under the loose soil condition.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.2
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• pp.181-186
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• 2022

Dam slope RIM is a highly important contact interface where the main body and the base surface are connected. In general, when the grouting for the slope of the dam structure is designed, it is planned using limited data (drilling, geological map, etc.). This makes it very difficult to accurately consider the original ground characteristics of the slope RIM grouting target, In addition, when the grouting volume planned during the design is drilled and injected into the original ground where the waterstop is secured, there is a possibility that the original ground with the waterstop is disturbed and the effect of the waterstop is rather diminished. In order to overcome such problems, it is more suitable to first consider geological conditions and determine whether to perform optimal grouting on the original ground through on-site repair tests before performing RIM grouting. In this paper, to determine the grouting of the RIM unit, a pilot hole water pressure test was performed on the rock of the slope in the target section. The analysis shows grouting volume of 1 Lugeon or less, and the cement injection amount also shows the injection result of 1 kg/m or less. In this case, performing grouting is rather counterproductive. This result can be evaluated through a rock of which some degree of order of mass is secured, as it is a dam design standard of 1 Lugeon or less when analyzed, using the results of visual observation and geological map creation during slope cutting. Therefore, in conclusion, it is preferable to make the decision for using RIM grouting on the slope of the dam body structure, based on 1 Lugeon in a rock state, and the cement injection amount also at 1 kg/m.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.99-106
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• 2005

본 연구에서는 케이싱을 영구부재로 사용함으로써 기존의 현장타설말뚝과 비교하여 시공 성,품질균일성,경제성, 내구성 등을 검토한다. 연구결과 케이싱을 영구부재로 사용하는 경우, 케이싱의 재사용을 위한 인발작업이 불필요하게 되고,말뚝길이전체에 대하여 케이싱을 사용한다면 R.C.D공법에 서 적용하는 슬러리공벽보호공정이 불필요하므로 시공성이 향상되는 것으로 판단된다. 케이싱을 영구부 재로 사용하는 현장타설말뚝의 지지력은 일반 깊은 기초의 지지력을 산정하는 방법과 동일하게 구해질 수 있다. 대구경의 영구케이싱이 있는 현장타설말뚝을 시공한다면 공내에 간단한 장비와 인력을 투입해서 선단부를 그라우팅방법 등으로 강화시킴으로써 선단지지력을 효과적으로 증대시킬 수 있을 것이다. 또한 케이싱 내부로부터 미리제작한 구멍을 통하여 그라우팅, 전단키(shear key) 등을 주입 또는 압입 함으로써 주면마찰력도 크게 향상될 수 있을 것으로 사료된다.

• Journal of the Korean Geotechnical Society
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• v.21 no.1
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• pp.43-50
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• 2005

Jet grouting method is widely being used in many geotechnical problems, especially for the purpose of reinforcement of clayey ground and cut-off wall of sandy ground. However, its design depends on highly empirical method, in which many researches have been undertaken. This study investigated the effect of cavitation on jet grouting. Small-scaled model tests were carried out using specially designed and fabricated device to analyze the effect of cavitation on jet grouting with various test conditions including ground condition, injection pressure, and injection time. The test results show that cavitation has a significant effect on jet grouting, and it has a potential for engineering application.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.989-1002
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• 2018

Grouting for the rock joint is to strengthen the rock strata by infiltrating cement grout materials into the rock joints. Grouting is one of a field of study which is difficult to develop deterministic and quantitative design approach because of multiphase behaviors of grout materials and 3 dimensional features of rock joints. Therefore, GIN (Grouting Intensity Number) can be a good index with appropriate monitoring of pressure and volume of grout. In this paper, we investigate the effects of joint roughness (JRC) and rheology of cement material during the infiltration of cement grout material into rock joint through CFD (computational fluid dynamics) analyses. With rough joint surface and increase of WC ratio, the frictional resistance during the grouting increases. The results have been summarized with polynomial correlations.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.579-584
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• 2003

In this study, anisotopic yield function is proposed for the numerical analysis of reinforced tunnel ground with grouting. For this, material properties of the reinforced ground both by equilibrium as well as kinematic condition along the interface and by the mean field theory of Eshelby (1957) and Zhao (1990) are compared with each other and, as a result, the advantage/disadvantage of the proposed models are summarized. Finally, reinforced ground around tunnel with grouting is analyzed numerically. A new anisotropic yield function model is shown to be more reliable than the previous one and the predicted result is agreeable with the experimental data available.

• Journal of the Korean GEO-environmental Society
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• v.17 no.12
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• pp.45-54
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• 2016

In this study, the construction method of new underground continuos impervious wall that the bentonite slurry keeps the stability of excavated trench and the mixture of cement and bentonite plays a role as a constituent of impervious wall in the trench. The merit of homogeneity of the method so called as a cement-bentonite slurry wall enables to accurately make an estimation of hydraulic conductivity of the walls compared with that by other general grouting methods and to verify their waterproof efficiency without difficulty at the design stage. The use of cement-bentonite slurry walls for the containment of groundwater flow has also proven a cost-effective impervious wall technology by employing the simple combination of construction equipments and easy and fast construction procedures. The engineering characteristics of cement-bentonite impervious wall obtained by carrying out the laboratory experiments under various conditions. This study reveals the effect of variation of constituent materials and their mixing methods (Water-Cement-Bentonite) on the engineering characteristics of a composition. Also, this study makes some recommendations on the optimum mixing ratio and mixing sequence for the best quality at the site. That is the most important factors to estimate the construction cost and design of the technique. The comparison is lastly made to evaluate the effect of ordinary Portland and blast furnace slag cement as a bonding material on the behavior of impervious walls.