• Proceedings of the Korean Geotechical Society Conference
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• 1999.02a
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• pp.1-13
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• 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 Embryo Transfer
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• v.25 no.3
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• pp.179-187
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• 2010

Embryonic compaction is essential for normal preimplantation development in mammals. The present study was to investigate the effects of compaction patterns on developmental competence of pig embryos. The proportion of blastocyst formation derived from compacted morula was higher than those of compacting and pre-compacting morula (P<0.01). Nuclei numbers of inner cell mass (ICM), trophectoderm (TE), and total of blastocysts derived from compacted group were also superior to those of compacting and pre-compacting groups (P<0.05). Then, compaction patterns, developmental ability and structural integrity were compared between mono- and poly-spermic embryos. The rate of compacted morula in mono-spermic embryos was higher than that of poly-spermic embryos (P<0.05). Especially, the rate of blastocyst formation derived from compacted embryos in mono-spermic embryo group was higher than that of poly-spermic embryo group (P<0.05), although no difference was detected between the two groups in the structural integrity. Finally, we confirmed that beta-catenin was differentially expressed according to compaction patterns in morula and blastocyst stage embryos. In conclusion, our results suggest that the compaction patterns during preimplantation development play a direct role in developmetal competence and quality of pig embryos.

• Magazine of the Korean Society of Agricultural Engineers
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• v.33 no.4
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• pp.84-95
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• 1991

The compaction ratio of the field dry density to the maximum dry density is generally adopted as the index of quality control for embankment of earthfill structures such as Earth Dam, Sea Dike, River Bank and Road. In case of coarse materials are included in the earth material, the compaction ratio will be varied in wide range since the dry density is influenced by quantity of coarse material in the soil. The treatment for the coarse material should be controlled carefully in testing. In this study, the compaction characteristics of the soil contained the coarse materials were researched and calibration of the suitability of field quality control methods were carried out. 28 Samples were made of clay(CL) and sandy soil (SM) mixed with gravel whose content were 0, 4, 6, 8, 10, 12, 15, 20, 25, 30, 35, 40, 45, and 60% in Weight. The compaction characteristics depending on the coarse material content were analysed through 4 types of compaction tests which are A-1, B-i, C-i and D-1. The adjusting coefficients for density and moisture content namely a and ${\beta}$ respectively were proposed in order to consider the effects depending on content of the coarse materials. The test methods to control reasonably and promptly the quality of earthfill were proposed after analysing the ranges of possible errors on the relative compaction ratio between laboratory compaction methods and field density testing methods.

• Geomechanics and Engineering
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• v.18 no.5
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• pp.471-480
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• 2019

The constructions of engineering structures such as airports, highways and railway on clayey soils may create many problems. The economic losses and damages caused by these soils have led researchers to do many studies using different chemical additives for the stabilization of them. Lime is a popular additive used to stabilize the clayey soils. When the base course is stabilized by mixing with an additive, inevitable delays may occur during compaction due to reasons like insufficient workers, breakdown of compaction equipment, etc. The main purpose of this study is to research the effect of compaction delay time (7 days) on the strength, compaction, and dynamic properties of a clay soil stabilized with lime content of 0, 3, 6, 9, 12 and 15% by dry weight of soil. Compaction characteristics of these mixes were determined immediately after mixing, and after 7 days from the end of mixing process. Within this context, unconfined compressive strength (UCS) under the various curing periods (uncured, 7 and 28 days) and dynamic triaxial tests were performed on the compacted specimens. The results of UCS and dynamic triaxial tests showed that delayed compaction on the strength of the lime-stabilized clay soil were significantly effective. Especially with the lime content of 9%, the increase in the shear modulus (G) and UCS of 28 days curing were more prominent after 7 days mellowing period. Because of the complex forms of hysteresis loops caused by the lime additive, the damping ratio (D) values differed from the trends presented in the literature and showed a scattered relationship.

• Journal of the Korean Geotechnical Society
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• v.21 no.2
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• pp.67-84
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• 2005

This research was conducted to evaluate the effectiveness of reinforcement for nearly saturated soft clay compaction. The effectiveness was investigated by roller compaction test using nearly saturated clay specimens. The nearly saturated condition was obtained by submerging clay in the water for 12 hours. High water content specimens were compacted in plane strain condition by a steel roller. A specimen was compacted by four 5 cm horizontal layers. Specimens were prepared fur both reinforced and unreinforced cases to evaluate the effectiveness of reinforcement. Used reinforcement is a composite consisted of both woven and non-woven geotextile. The composite usually provides drainage and tensile reinforcement to hi인 water-contented clay so that it increases bearing capacity. Therefore, large compaction load can be applied to reinforced clay and it achieves higher density effectively. The reinforcement also increases compaction efficiency because it reduces the ratio between shear and vertical forces during compaction process. The maximum vertical stress on the base of specimen usually decreased with higher compaction thickness. The reinforcement increases soil stiffness under the compaction roller and it initiates stress concentration. As a result, it maintains higher vertical stress level on the base of specimen that provides better compaction characteristics. Based on test results, it can be concluded that the reinforcement is essential to achieve effective compaction on soft clay.

• Journal of the Korean Geosynthetics Society
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• v.17 no.1
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• pp.65-74
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• 2018

The degree of compaction of embankments is generally measured using the sand replacement method or a soil density gauge. However, these methods include coarse particles, which are relatively large. The degree of compaction is overestimated if the in-situ soil density is simply compared with the density obtained from a Proctor compaction test (KS F 2312, 2001), because the density of coarse particles is higher than that of soil. However, there is no recommended correction for the coarse particle ratio in Korea, thus intentionally increasing the degree of compaction for structures to which large loads are applied or for which compaction is critical. Here, a correction considering the Korean Proctor compaction test and the difference between the maximum allowable particle sizes was recommended after corrections for coarse particle ratios in other countries were collected and analyzed. The degree of compaction was re-estimated by applying the recommended correction to the results of both Proctor compaction and sand replacement tests. The degree of compaction without the correction of coarse particle ratio was overestimated, because the re-estimated degree of compaction decreased as the coarse particle ratio increased. The relatively accurate results obtained from the field application of the correction will offer long-term cost savings due to reduced maintenance fees during operation.

• Journal of the Korean GEO-environmental Society
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• v.23 no.8
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• pp.11-16
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• 2022

The compaction process using vibrating rollers in road construction is essential to increase soil stiffness in earthworks. Currently, there is no clear standard for the operation method of the compaction roller during compaction. Although simple quality inspection techniques have been developed, plate load test (PLT) and field density test (FDT) are the most frequently used test methods to evaluate the degree of compaction during road construction as the most frequently used quality inspection methods. However, both inspection methods are inefficient because they cannot perform quality inspection in all sections due to time and cost reasons. In this study, we analyzed how the operating conditions of vibrating rollers affect the compaction quality. An intelligent quality management system, which is a currently developed and commercialized technology, was used to obtain quality inspection results in all sections. As a result of the test, it was analyzed that the speed and vibration direction of the compaction roller had an effect on the compaction degree, and it was found that the compaction direction had no effect on the compaction degree.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.717-724
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• 2003

Although sand compaction pile is applied considerably for increase of hearing capacity in domestic, it is getting more necessary to develope the alternative materials because of exhaustion and increase of unit cost of sand. In this study, stress concentration ratio between crushed-stone pile and soft ground was measured and, a displacement ratio 30, 40 and 50%, variation of stress concentration ratio was analyzed. As an increase displacement ratio, the stress concentration effect of crushed-stone compaction pile doesn't increase proportionally and effect of ground improvement in case of ground was good at displacement ratio 30% or 40%. The stress concentration ratio of crushed-stone compaction pile in group piles is 1.5 times that of crushed-stone compaction pile in single pile.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.183-190
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• 2000

Effective range of Hydraulic Hammer Compaction was studied by numerical analysis instead of empirical method. Numerical analyses were carried out with commercial FEM code, ABAQUS, and verified by comparing the numerical results with field tests of Hydraulic Hammer Compaction. Most of material properties were evaluated by data from laboratory and in-situ tests. Vertical effective range was estimated by distribution curve of plastic strain energy dissipated through soil layers under dynamic load and these results were in good agreement with field tests. Based on verification, the effects of governing properties of Hydraulic Hammer Compaction such as number of hit can be determined by numerical analyses. In addition, vertical effective range can also be determined by Menard's empirical equation using the external work at converging time of plastic strain energy in numerical analysis. This implies that the minimum energy of Hydraulic Hammer Compaction for improvement can be determined by Menard's equation.

• Journal of Powder Materials
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• v.9 no.6
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• pp.433-440
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• 2002

Synthesis and compaction of Al-base nano powders by pulsed discharge method were investigated. The aluminum based powders with 50 to 200 nm of diameter were produced by pulsed wire evaporation method. The powders were covered with very thin oxide layer. The perspective process for the compaction and sintering of nanostructured metal-based materials stable in a wide temperature range can be seen in the densification of nano-sized metal powders with uniformly distributed hard ceramic particles. The promising approach lies in utilization of natural uniform mixtures of metal and ceramic phases, e.g. partially oxidized metal powders as fabricated in our synthesis method. Their particles consist of metal grains coated with oxide films. To construct a metal-matrix material from such powder, it is necessary to destroy the hard oxide coatings of particles during the compaction process. This goal was realized in our experiments with intensive magnetic pulsed compaction of aluminum nanopowders passivated in air.