• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.347-354
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• 2002

In this paper, when structures are constructed in the soft ground with poor bearing capacity at Incheon International Airport(railroad area), as for the grouting columns built In soft ground by high pressure jet grouting with Triple tube rod(super injection grouting), the effects on reinforcement and bearing capacity of ground are investigated. A unconfined compressive strength tests has been performed on the specimens sampled from the grouting columns and a mass plate bearing test has been performed on a grouting column. The test results show that super injection grouting has a sufficient effect on composite ground improved of foundation ground and reatraint of settlement of structure.

• Geomechanics and Engineering
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• v.12 no.5
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• pp.739-752
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• 2017

This study was intended to evaluate the improved strength of the ground by applying the bio grouting method to a loose sandy ground. The injection material was prepared in the form of cement-like powder, with the bio injection material produced by microbial reactions. The grouting test was conducted under the conditions similar to the field where the bio injection material can be applied. In addition, the injection materials (cement and sodium silicate No. 3) used for Labile Waterglass (LW) method and the conventional grouting methodwere prepared through a two-solution one-step process. The injection into the specimens was done at a pressure of 150 kPa and then, with a bender element, their moduliof elasticity were measured on the 7th, 14th, 21st and 28th curingdays to analyze their strengths according to the duration of curing. It was confirmed that in all injection materials the moduli of elasticity increased over time. In particular, when 30% of the bio injection material was added to 100% cement, the modulus of elasticity tended to increase by about 15%. This confirmed that the applicability became higher when the bio injection material was used in place of the conventional sodium silicate.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.619-626
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• 2002

In this study, a correlation among pressure, time and quantity of injection was organized from the laboratory tests, which were executed many times representing in-situ soil conditions carefully and then it would be applied to the in-situ soil injection simulator which will be developed for optimal injection into the ground. The sort of sample soils were both sand(A specimen) and silty sand(B specimen). Injection tests were gone into operation by compaction state, injection velocity and the depth individually. In the ground improved with permeation Infection, the relation among injection pressure of the same depth, the injected quantities and time were systematic by the depth. By defining the limit range of injection pressure and quantity about the variety of a linear equation obtained from lining each of their trend, the application of laboratory injection monitoring program and the data to evaluate its realization were produced. In the ground improved with root type injection, the relation between injection pressure and the injected quantities was irregular because fracture state occurred quickly.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.53-67
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• 2001

In this study the pilot test of CGS as injection method by low slump mortar was performed and the results were analyzed in order to find out the application of this method and effect of settlement restraint. The site far pilot test is adjacent to apartments supported by pile foundations. Sand drain method was performed previously as countermeasures against settlement, but settlement occur continuously because this ground is very soft. Site investigations such as SPT, DCPT and vane shear test were performed to determine the characteristics of ground improvement. Field measurements and FDM analysis were performed on purpose to find out the displacement of ground during injection works. From the results of this study, CGS method can be optimized by the control of diagram, space, depth, injection material, and injection pressure. CGS improved soft ground compositely by the bearing effect of CGS columns and reinforcement of adjacent ground. Considering that increase of N value is about 2.1, CGS can be considered as an effective method to increase the bearing capacity as well as to stop the settlement of soft ground. It is also expected to be economic and effective in improvement of ground when it is used in applicable sites.

• 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$^2$.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.611-618
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• 2002

In this study the CGS as an injection method by low slump mortar was performed the pilot test to confirm the applicability of this method and the effectiveness of settlement restraint. From the results, there has been concluded the construction control standard such as an institutional diameter, space, depth, injection materials, Infection pressure etc. Also, there has been estimated the ground improvement effectiveness which has resulted from the field investigation and consolidation test etc. From the results, in the adjacent ground the CGS, generally, has been confirmed to in-crease ground strength to improve the consolidation characteristic obtained from the field investigation and consolidation test. Especially, the CGS which performed the larger stiffness to the ground has been concluded that the settlement restraint to the ground complicates the ground effect which Increases the bearing capacity and stress assignment. So, the CGS can be considered as an effective method to increase the bearing capacity as well as the settlement restraint of soft ground.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.2
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• pp.175-182
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• 2002

The cement injection technology on the purpose of ground reinforcement and cut-off has been used in construction sites until now. However, recently it is applied to prevent leakage of underground structure. In this study, applicability of the back side waterproof grouting method was verified through performing field model tests and reviewing case histories. From the results of this study, injection shape of the back side waterproof grouting method was appeared to be root type, and waterproof effect by injection of cement grout material was excellent because grout material infiltrated into boundary between wall of structure and back side ground to be waterproof layer. Components influencing infiltration of injection material are type of soil and degree of compaction. For effective injection, injection pressure has to vary gradually from high pressure to low pessure and small quantity of injection material has to be injected for long times. Also, spacing of injection hole must be designed considering condition of back side ground, injection area, W/C ratio, the number of injection and injection pattern properly.

• 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.

• Geomechanics and Engineering
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• v.18 no.1
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• pp.59-69
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• 2019

Grout injection is mainly used for permeability reduction and/or improvement of the ground by injecting grout material into pores, cracks, and joints in the ground. The oscillatory grout injection method was developed to enhance the grout penetration. In order to verify the level of enhancement of the grout, field grout injection tests, both static and oscillatory tests, were performed at three job sites. The enhancement in the permeability reduction and ground improvement effect was verified by performing a core boring, borehole image processing analysis, phenolphthalein test, scanning electron microscopy analysis, variable heat test, Lugeon test, standard penetration test, and an elastic wave test. The oscillatory grout injection increased the joint filling rate by 80% more and decreased the permeability coefficient by 33-68%, more compared to the static grout injection method. The constrained modulus of the jointed rock mass was increased by 50% more with oscillatory grout injection compared to the static grout injection, indicating that the oscillatory injection was more effective in enhancing the stiffness of the rock mass.

• Geomechanics and Engineering
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• v.25 no.1
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• pp.31-40
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• 2021

Injection grouting is one of the most common ground improvement practice to increase the strength and reduce the hydraulic conductivity of soils. Owing to the environmental concerns of conventional grout materials, such as cement-based or silicate-based materials, bio-inspired biogeotechnical approaches are considered to be new sustainable and environmentally friendly ground improvement methods. Biopolymers, which are excretory products from living organisms, have been shown to significantly reduce the hydraulic conductivity via pore-clogging and increase the strength of soils. To study the practical application of biopolymers for seepage and ground water control, in this study, we explored the injection capabilities of biopolymer-based grout materials in both linear aperture and particulate media (i.e., sand and glassbeads) considering different injection pressures, biopolymer concentrations, and flow channel geometries. The hydraulic conductivity control of a biopolymer-based grout material was evaluated after injection into sandy soil under confined boundary conditions. The results showed that the performance of xanthan gum injection was mainly affected by the injection pressure and pore geometry (e.g., porosity) inside the soil. Additionally, with an increase in the xanthan gum concentration, the injection efficiency diminished while the hydraulic conductivity reduction efficiency enhanced significantly. The results of this study provide the potential capabilities of injection grouting to be performed with biopolymer-based materials for field application.