• Journal of the Korean Geotechnical Society
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• v.20 no.2
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• pp.115-124
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• 2004

Granular compaction pile has the load bearing capacity of the soft ground increase and has the settlement of foundation built on the reinforced soil reduce. The granular compaction group piles also have the consolidation of the soft ground accelerate and prevent the liquefaction caused by earthquake using the granular materials such as sand, gravel, stone etc. However, this method is not widely used in Korea. The granular compaction piles are constructed by grouping them with a raft system. The confining pressure at the center of bulging failure depth is a major variable in estimating the ultimate bearing capacity of the granular compaction piles. Therefore, a share of loading is determined considering the effect of load concentration ratio between the granular compaction piles and surrounding soils, and the variation of the magnitude of the confining pressure. In this study, a method for the determination of the ultimate bearing capacity is proposed to apply a change of the horizontal pressure considering bulging failure depth, surcharge, and loaded area. Also, the ultimate bearing capacity of the granular compaction pile is evaluated on the basis of previous study(Kim et al., 1998) on the estimation of the ultimate bearing capacity and compared with the results obtained from laboratory scale model tests and DEM numerical analysis using the PFC-2D program.

• Journal of the Korean Geotechnical Society
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• v.37 no.9
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• pp.25-36
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• 2021

Recently, the intelligent compaction technology for quality control of earthworks has brought attention as a quality control standard for earthworks. In this study, intelligent compaction technology and earthwork quality control methods were investigated and earthwork quality control procedures using intelligent compaction technology were considered based on field tests. Through the field compaction test of the silty sand (SM) fill material, it was confirmed that CMV and bearing capcaity index from plate load tests increased as the number of compactions increased. Based on the field test data, the average CMV and quality control target CMV were derived. The target CMV (34.2) was calculated through the correlation with the bearing capacity index of the plate load test, and the target CMV (36.6) was calculated through the analysis of the CMV increase rate. In this paper, the on-site compaction quality management procedure and methodology using intelligent compaction technology were discussed, and an intelligent compaction quality management method was proposed to promote the applicability of the technology.

• Journal of the Korean Geotechnical Society
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• v.21 no.3
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• pp.159-168
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• 2005

In the previous studies, settlement behaviors of granular compaction piles have generally been analyzed with an evaluation of the settlement reduction factor based on tile load-sharing ratio and the replacement ratio. In this approach, however, since the reinforced ground with granular compaction piles is simplified as the composite ground, only the difference of a relative vertical strength between piles and soils is taken into account without reflecting lateral behaviors of granular compaction piles. In the companion research paper, the method of estimating the settlement of granular compaction piles was proposed by synthetically considering a vertical strength of the ground, lateral behaviors of granular compaction piles, the strength of pile materials, a pile diameter, and an installation distance of the pile. In the presented study, to validate a propriety of the previously proposed method, large scale field load tests and three dimensional numerical analyses are performed. The results are analyzed in detail and compared with the predicted settlements by the proposed method. Finally, a simple method to estimate the settlement of granular compaction piles is suggested for an easy application of the practical design.

• Journal of Industrial Technology
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• v.25 no.A
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• pp.67-73
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• 2005

In this research, centrifuge model experiments and numerical approach of finite element method to analyze experimental results were performed to investigate the behavior of improved ground with sand compaction piles. One of typical clay minerals, kaolinite powder, were prepared for soft ground in model tests. Jumunjin standard sand was used to sand compaction pile installed in the soft soil. In order to investigate the characteristics of mechanical behavior of sand compaction piles with low replacement ratios, centrifuge model experiments with the replacement ratio of 40%, changing the width of improved area with respect to testing results the width of surcharge loads, were carried out to obtain of bearing capacity, characteristics of load-settlement, vertical stresses acting on the sand pile and the soft soil failure mechanism in improved ground.

• Journal of Bio-Environment Control
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• v.24 no.3
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• pp.202-209
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• 2015

This study compared and analyzed the measurements of pullout load according to the depth of reclamation in the foundation, compaction ratio of soil, spiral diameter, and soil textures in an experiment with a model and reached the following conclusions: The comparison results of extreme pullout load between farm and reclaimed soil show that farmland soil recorded a score that was 1.2~3 times higher than that of reclaimed soil. The investigator measured pullout load in farmland and reclaimed soil and observed a tendency of rising extreme pullout load according to the increasing depth of reclamation and compaction ratio with a similar load-displacement curve between the two types of soil. Extreme pullout load made a greater increase by the rising size of diameter than the increasing depth of reclamation, also making a considerably bigger increase according to the rising compaction ratio than the other conditions. Therefore, the spirals bar is expected to be available in soft soil foundation, as well as farmland as increasing buried deep of foundations, compaction rate, diameter of the spiral, ect.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.435-440
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• 2000

It is important to pay careful attention to construction backfill for the structural integrity of concrete box culvert. The stability of the surrounding soil is important to the structural performance of most culverts. Good compaction by the dynamic compaction roller with big capacity is as effective as good backfill materials to increase the structural integrity of culvert. However structural distress of the culvert could be occur due to the excessive earth pressure by dynamic compaction load. In this study, 16 box culverts were constructed with various compaction materials and construction methods. Three types of on-site soils such as subbase, subgrade and roadbed materials were used as backfill materials in the test program. Compaction methods were adapted based on the site conditions. In most cases, dynamic compaction rollers with 10 to 16 ton weights were used and vibration speed were applied from 2400 to 2500 rpm for the great compaction energy. Some backfill compactions with good quality soils were carried out to examine the effect of EPS(Expanded Polystyrene) panels with changes of compaction thickness. This paper presents the main results of the research conducted to access the engineering performance of the backfill materials. The characteristics of earth pressures are discussed. It is observed that subgrade and roadbed materials are needed more careful compaction than subbase materials. It is shown that EPS panels are effective to mitigate dynamic lateral earth pressure on the culverts. It is also obtained that the dynamic pressure depends on the soil properties. In addition, the coefficient of dynamic earth pressure (K$\sub$dyn/=ΔP$\sub$H/ ΔP$\sub$V/) during compaction is discussed.

• Magazine of the Korean Society of Agricultural Engineers
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• v.31 no.1
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• pp.82-95
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• 1989

This study was carried out for the stability analysis of earth dam by the variation of compaction density. The test samples were taken from five kinds of soil used for banking material and the degree of compaction for this samples were chosen 100, 95, 90, 85, and 80 percent. The stability problems were analysed by the settlement and camber( extra banking) of dam, strength parameter and dam slope, and coefficient of permeability and seapage flow through dam body. The results of the stability analysis of earth dam are as follows. 1. The more the fine particle increases and lower the compaction degree becomes, the lower the preconsolidation load becomes but the compression index becomes higher. 2. Sixty to eighty percent of settlement of dam occurs during the construction period and the settlement ratio after completion of dam is inversly proportional to the degree of compaction. 3. The camber of dam has heigher value in condition that it has more fine particle(N) and heigher dam height(H) with the relation of H= e(aN-bH-e). 4. The cohesion(C) decreases in proportion to compaction degree(D) and fine particle(N) with the relation of C= aD+ bN-c, but the internal friction angle is almost constant regardless of change of degree of compaction. 5. In fine soil, strength parameter from triaxial compression test is smaller than that from direct shear test but, they are almost same in coarse soil regardless of the test method. 6. The safety factor of the dam slope generally decreases in proportion to cohesion and degree of compaction but, in case of coarse soil, it is less related to the degree of compaction and is mainly afected by internal friction angle. 7. Soil permeability(K) decreases by the increases of the degree of compaction and fine particle with relation of K=e(a-bl)-cN) 8. The more compaction thickness is, the less vertical permeability (Kv) is but the more h6rzontal permeability (KH) is, and ratio of Kv versus KH is largest in range from 85 to 90 percent of degree of corn paction. 9. With the compaction more than 85 percent and coefficient of permeability less than ${\alpha}$X 10-$^3$cm/sec, the earth dam is generally safe from the piping action.

• Journal of the Korean Geosynthetics Society
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• v.22 no.4
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• pp.9-15
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• 2023

Compaction is performed in civil engineering sites to secure the stability of the ground and prevent settlement. While the process of compaction is crucial, it is also essential to evaluate the degree of compaction after the completion of the process. In domestic sites, the evaluation of compaction is mainly conducted on a small number of spot using point-based tests such as plate load tests and sand cone tests. The methods presented so far allow assessment of surface compaction, but evaluating compaction in deeper layers poses challenges. Moreover, due to the limited coverage of point-based testing, it is difficult to achieve an overall assessment of compaction. As a solution to these issues, the Spectral-Analysis-of-Surface-Waves (SASW) tests were utilized to evaluate compaction. SASW tests offer a broader measurement range compared to point-based tests, and depending on the test setup, this method can provide the stiffness of the ground at greater depths. In this study, SASW tests were conducted in a compacted soil site under different conditions to assess compaction. Additionally, Nuclear Density Gauge tests were conducted concurrently to compare and verify the results of SASW. The research results confirmed the feasibility of evaluating compaction using SASW at the geotechnical site.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.02a
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• pp.1-11
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• 2000

The use of Compaction Grouting evolved in 1950's to correct structural settlement of buildings. Over the almost 50 years, the technology has been 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 applications 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 applications include preventing liquefation, re-leveling settled structures, and using compaction grout bulbs as structural elements of minipiles or underpinning. In this paper, on the basis of the case history constructed in this year, a study has been performed to analyze the basic mechanism of the Compaction Grouting. Also, the effectiveness of the ground improvement and the bearing capacity of the Compaction Pile has been verified by the Cone Penetration Test(CPT) and Load Test. Relatively uniform Compaction grouting column could be maintained by planning the Quality Control in the course of grouting. And, the Quality Control Plan has been conceived using grout pressure, volume of grout and drilling depth.

• Journal of the Korean Geotechnical Society
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• v.20 no.7
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• pp.183-196
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• 2004

Sand Compaction Pile (SCP) is a soft-ground improvement technique used for not only accelerating consolidation but also increasing bearing capacity of soils. In this study, laboratory tests and 3-D finite element analysis were peformed to investigate the characteristics of load transfer in SCP with an emphasis on free-strain behavior of piles with low replacement ratios in the range of 30 to $50\%$. Through these focused tests and numerical analyses, we proposed a simplified method to analyze the load transfer characteristics of SCP in soft ground. Moreover, it was shown that estimated normal stresses in SCP using the proposed method were in a reasonable agreement with actual values.