• Journal of the Korean Geotechnical Society
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• v.18 no.6
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• pp.61-72
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• 2002

In this study, model tests were performed to evaluate the injection characteristics of cement grouting which was used as waterproof method for leakage of underground structures. To simulate in situ condition, model tests were performed with varying the ground conditions such as the kinds of test soils, soil density, water content, etc. and the injection conditions such as kinds of injection materials, injection pressure, injection quantity, injection velocity, etc. From the results of model tests, the major factors influencing the permeability of injection material were determined to be the kinds of soils and soil density. To obtain optimal injection effects, injection should be performed after investigating the condition of backside ground accurately.

• Journal of the Korean GEO-environmental Society
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• v.25 no.5
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• pp.15-19
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• 2024

This study aimed to develop high-efficiency grouting techniques under deep-depth conditions by experimentally verifying the applicability of various injection materials. Particle size analysis and injection model experiments were conducted with Ordinary Portland Cement (OPC) and Micro Cement (MC) to evaluate the injection performance of each material. Using Barton's Cubic Network theory, the rock fracture spacing was calculated for domestic deep-depth standards, specifically below 40 meters underground. The analysis of particle size passability under selected conditions showed that MC could pass through the rock fracture gaps, while OPC could not. According to the results of the injection model experiments using experimental devices and area calculation software, OPC failed in injection due to its larger particle size, whereas MC was capable of injection even under high-viscosity conditions. Based on these findings, the study quantitatively and visually derived the applicability of grouting materials under deep-depth conditions, and high-viscosity MC material is expected to be effective for waterproofing enhancement in deep-depth rock fracture surfaces.

• Journal of the Korean Geotechnical Society
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• v.26 no.7
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• pp.37-47
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• 2010

To improve the grout penetration characteristics, a vibratory grout injection technique was adopted in this study. It is a technique of grout injection in which an oscillating pressure is added to the steady-state pressure as an injection pressure. By applying the vibration during grout injection, cement particles will become less adhesive and the clogging tendency will be decreased. A series of pilot-scale chamber tests were performed to verify the enhancement of the groutability by applying the vibratory grout injection; assessment on the change of the lumped parameter $\theta$ which represents a barometer of clogging phenomenon was made. Moreover, the effect of vibratory grout injection through the joint was also investigated using artificially made rock joints. Experimental results as well as analytical results show that the grout penetration depth can be substantially improved by vibratory grouting. Moreover, it was found that enhancement of the permeation grouting due to vibratory injection is more dominant at grouting pressure less than 400 kPa.

• Journal of the Korean Geotechnical Society
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• v.19 no.2
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• pp.217-225
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• 2003

The ground reinforcement effect of pressure grouting depends on grout penetration into ground. It is not, however, easy to predict the grout penetration in the design process because of the heterogeneity of ground conditions. This study investigates the proper grouting pressure and grouting method through laboratory model tests for pressure grouting using loose to medium dense crushed rock and sandy ground using specially designed and fabricated device. The optimum injection pressure, grout quantity and injection time are investigated through performing pressure grouting under changing conditions of injection in this test. From the test results, it was found that optimum injection pressure covers the range of 3 to 4kg/cm$^2$.

• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.229-236
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• 2002

In this study, the characteristics of chemical grouting, such as solidification, penetrability, were analyzed experimentally by grain size of grout materials and permeability, relative density of the ground. For evaluating applicability of grout material, solidification tests and permeability tests were peformed. From the results of the tests, effective solidification ratio and penetrability ratio of Micro Cement were 75% and 86% respectively when ground permeability was in the range of 10$^{-4}$ to 10$^{-2}$cm/sec. On the other hand, effective solidification ratio and penetrability ratio of Ordinary Portland Cement (OPC) were both lower than 50%. When penetrability of grout material is needed for improvement of dam foundation and soft ground, application of Micro Cement is much superior to that of the other materials. The results of the grouting tests in the hydrodynamic ground show that the 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, the solidifcation effect of long gel-time grout material is very poor because most grout materials are outflowed.

• Journal of Korea Water Resources Association
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• v.31 no.6
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• pp.667-674
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• 1998

Numerical models simulating the process of NAPL from contaminated soil or groundwater through steam injection can be a useful tool for designing and evaluating the cleanup strategy under various field conditions. One and two dimensional numerical analyses were conducted based on the governing equations describing the NAPL removal as a non-isothermal, multi-phase and multi component process. Relatively good agreements were obtained between the numerical results and the observations from one-dimensional laboratory experiment, except some discrepancy due to experimental difficulties. Simulation effectively identified the steam displacement process of xylene floating on the water table and TCE sinking on the aquifer bottom in a two-dimensional analysis. Overall, simulation models have a high potential in the design/appraisal of a system for field application of the technique as well as in the examination of complex processes such as vaporization which is hard to identify experimentally.

• 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 Korean Geotechnical Society
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• v.15 no.3
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• pp.99-111
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• 1999

The frictional capacity of auger-cast piles is often very small because of the disturbance of the soil surrounding the pile during the excavation process. Usage of expansive agents and a pressurized injection technique for auger-cast piles should improve the frictional resistance between pile and soil. This paper presents the test results of auger-cast model piles installed with expansive mortar in laboratory compacted weathered soil. The model piles were installed in a calibration chamber with a variation in the amount of expansive agent, the injection process and the chamber pressure. It was observed that the pile shaft resistance increases with the increased amount of expansive agent, and also increases when mortar is pressure injected. The shaft resistance increased up to 24% for the pile installed only with expansive mortar and increased up to 56% for the pile installed with the pressurized injection of expansive mortar, compared with that of piles with plain mortar.

• Journal of the Korean GEO-environmental Society
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• v.15 no.2
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• pp.75-82
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• 2014

Recently, public works becoming bigger in Jeju are implemented various kinds of ground reinforcement method including the chemical grouting method. In this study, we have been investigated on the proper material and the injection condition for the excellent injection effect and the excellent strength of injection material and the permanent waterproof and reinforcement through the experiment. The kind of injection material has been selected through the uniaxial compression test and the endurance test of injection material as the chamber test. An experiment was performed with model ground made of scoria, the injection performance of selected material has been identified through the evaluation test of injection range using the decision test of injection amount and the calibration chamber test. As a result of test, it has been analyzed that MSG appeared to have the excellent strength, durability and injection performance all compared with the ordinary cement, this result is judged to be possible as the ancillary data of design at time of design and construction with the chemical grouting method in the future.

• 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.