• Proceedings of the Korean Geotechical Society Conference
• /
• 2001.03a
• /
• pp.425-432
• /
• 2001

Compaction Grouting System, the method which makes ground compact by injection of low slump mortar, Is widely used for reinforcement of soft ground, restoration of structures happened differential settlement, underpinning and restoration of damaged dam core. The quantitive analysis of ground improvement for this method has not performed yet. So, design parameters about thls method must be studied through performance of CGS in various types of soil to make CGS adaptable widely. In this study PBT, SPT and field density test were performed for analysis of the characteristics of ground improvement and pressuremeter and inclinometer were installed for analysis of the characteristics of compaction in adjacent ground. In this paper, denoted much effects for filled ground that increasing of the bearing capacity, confirming the displacement of adjacent ground and the effective radius of injection.

• Proceedings of the Korean Geotechical Society Conference
• /
• 1999.02a
• /
• pp.1-13
• /
• 1999

The use of Compaction Grouting evolved in the 1950's to correct structural settlement of buildings. Over the almost 50 years, the technology has developed and is currently used in wide range of applications. Compaction Grouting, the injection of a very stiff, 'zero-slump' mortar grout under relatively high pressure, displaces and compacts soils. It can effectively repair natural or man-made soil strength deficiencies in variety of soil formations. Major uses of Compaction Grouting include densifying loose soils or fill voids caused by sinkholes, poorly compacted fills, broken utilities, improper dewatering, or soft ground tunneling excavation. Other application include preventing liquefaction, re-leveling settled structures, and using compaction grout bulbs as structural elements of minipiles or underpinning. The technique replaced slurry injection, or 'pressure grouting', as the preferred method of densification grouting. There are several reasons for the increased use of Compaction Grouting which can be summarized in one word: CONTROL. The low slump grout and injection processes are usually designed to keep the grout in a homogeneous mass at the point of injection, while acceptable in some limited applications, tends to quickly get out of control. Hydraulic soil fracturing can cause extensive grout travel, often well beyond the desired treatment zone. So, on the basis of the two case history constructed in recent year, a study has been peformed to analyze the basic mechanism of the Compaction Grouting and verify the effectiveness of the ground improvement using some test methods.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.11 no.1
• /
• pp.51-57
• /
• 2011

Irregular distributions of limestone cavity in Gang-Won province area may cause unexpected accidents from reduced serviceability or failure of structure. It is requested that an appropriate ground reinforcement method should be used to improve bearing capacity of structure, and the method should also be satisfied with environmental requirements. Among several methods used for foundation constructions in cavity area, Rod Jet Pile(RJP) method has been widely used. While the RJP method was used to improve bearing capacity for the railway bridge foundations, water pollutions of drinking water as well as fishery located adjacent to this project area were occurred. The main reason of the water pollution was cement runoff used in cement mortar during injecting material in RJP method. Laboratory tests were performed to prevent water pollution. The compaction mortar method using low movable material was selected for this project. The quality of water at a fishery adjacent to the site and the compressive strength of cores taken from the construction site were measured. Test results show that the water pollutions was minimized, and the average compressive strength of foundation material was over 5 MPa. As a result of this study, compaction mortar method can be used to ensure the bearing capacity of foundation and to prevent environment pollutions.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.03a
• /
• pp.480-488
• /
• 2010

The CGS method is non-discharge replacement method improving ground stiffness by the effect of static compaction with injecting very low slump mortar into ground, and is applied for increasing bearing capacity and filling ground cavity by lifting or restoring differential settled structures and preventing differential settlement. This paper suggests design of ground improvement and construction case history for civil engineering structures by CGS method. This method can be used for reinforcing soft ground and liquefaction of loose sandy soil. This method was used in SongDo area in Incheon Economic Free Zone due to its low vibration of ground while it can improve the soft soil where underground structures(subway and box culvert) are already existed.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.6 no.3
• /
• pp.211-220
• /
• 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.

• Journal of the Korean Geotechnical Society
• /
• v.39 no.5
• /
• pp.41-50
• /
• 2023

This study reviewed the liquefaction reinforcement and ground reinforcement methods widely used domestically and abroad through construction method characteristics and analyzed the economic feasibility and reinforcement efficiency of each reinforcement method. The analysis results were used to evaluate the applicability of the appropriate reinforcement method for the liquefaction reinforcement of new and existing structures. As a result of evaluating the applicability of the reinforcement method based on the economic feasibility and reinforcement effect of each reinforcement method, the compaction method, which secures the construct ability by applying large equipment, is advantageous when reinforcing a new structure, and the low-fluidity mortar injection method (C.G.S method) and the high-pressure injection method (J.S.P method) are considered appropriate in the existing structure.

• Journal of the Korean GEO-environmental Society
• /
• v.23 no.12
• /
• pp.17-23
• /
• 2022

This paper analyze the precast panel retaining wall's safety factor changes based on the numerical analysis using PLAXIS 2D software. Numerical analysis conditions include construction method, nail and panel fixing method, backfill material compaction conditions, rainfall conditions. The classification according to the construction method of the precast panel retaining wall includes the top-down and bottom-up methods. The difference between the top-down and bottom-up methods is the presence or absence backfill material and the ground excavation method. The top-down method involves vertically excavating the ground and attaching the panel using mortar, but in the bottom-up method, the ground is vertically excavated and harden the backfill material. As a result of numerical analysis, the top-down method secured a higher safety factor in all cases except the rainfall conditions.

• Journal of the Korean Geotechnical Society
• /
• v.37 no.3
• /
• pp.43-50
• /
• 2021

On the construction of new roads, the cut slope is inevitable and thus has been widely applied in the mountainous area. Particularly, the retaining wall with the precast concrete panel is often selected for its higher stability and mostly constructed in bottom-up method. However, the bottom-up method results in steeper slope as 1:0.05 before constructiong retaining wall and thus causes poor compaction at backfill which may induce instability during or after the construction. To overcome this problem, precast concrete panel retaining wall was attached in-situ ground (so called top-down). This paper presents the evaluation of drainage capacity of top-down method which has impermeable layer between panel and mortar being used to increase the ability of attachment of the precast concrete panel.

• Journal of the Korean Geotechnical Society
• /
• v.19 no.6
• /
• pp.307-323
• /
• 2003

In this study the pilot test of C.G.S (Compaction Grouting System) as injection method by low slump mortar was performed and the results were analyzed in order to find out the application of this method to the soft ground and the effect of settlement restraint. The site for pilot test is adjacent to apartments supported by pile foundations. Sand drain method was performed previously as countermeasures against settlement, but settlement occurs continuously because this ground is very soft. Site investigations such as SPT, CPT and vane shear test were performed to determine the characteristics of ground improvement after the installation of C.G.S. Field measurements were performed on purpose to find out the displacement of ground during the installation of C.G.S. From the results of this study, C.G.S method can be optimized by the control of radius, space, depth, injection material and injection pressure. C.G.S improves soft ground with radial consolidation of adjacent soft ground. Considering that increase of N value to about 3, C.G.S can be considered as an effective method to increase the bearing capacity as well as constrain the settlement of soft ground. It is also expected to be economic and effective in the improvement of ground when it is used in applicable sites.