• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.283-290
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• 2001

In this study, static Pile load tests and PDA for open-ended steel pipe pile($\phi$ = 609.6 mm, t = 14 mm) penetrated into the gravel layer(GP - GM) was accomplished and axial load distribution was measured. Based on the tests results, the ultimate bearing capacity and axial load bearing mode were examined. Also, the ultimate pile capacity was calculated by APIL $E^{PLUS}$./.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.277-284
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• 2000

Using the large diameter (D ＝ 2,500mm, L ＝ 40m) batter steel pipe piles, designed as compression piles but used as reaction piles during the static compression load test of socketed test piles (D ＝ 1,000mm, L ＝ 40m), static pile load tests for large diameter instrumented rock-socketed piles were performed. The reaction steel pipe piles were driven 20m into the marine deposit and weathered rock layer and then l0m socketed with reinforced concrete through the weathered rock layer and into hard rock layer. Steel pipe and concrete in the steel pile part, and concrete and rebars in the socketed parts were instrumented to measure strains in each part. The pullout amounts of reaction pile heads were also measured with LVDT. During the static pile load test, total compressional load of about 20MN was loaded on the head of test piles, but load above 20MN was not loaded due to lack of loading capacity of loading system. Over the course of the study, maximum pullout amount up to 7mm was measured in the heads of reaction piles when loaded op to 10MN and 1mm of pullout amount was measured. More than 85% of pullout load was transfered in the residual weathered rock layer and about 10% in the soft rock layer, which was somewhat different transfer mechanism in the static compressional load tests.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.705-712
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• 2005

Among soft ground treatment methods with granular soil used in domestic, the sand compaction pile method has been utilized greatly, but, as a result of exhaustion of sand and increase of unit cost, a necessity of an alternative method is suggested. In this study, the static load tests for group crushed-stone compaction piles which were constructed at in-situ site were performed. Pile diameter was 700mm and area of loading plates were changed. The static load tests of single and group piles were performed for area replacement ratio of 20, 30 and 40%. Based on test results, bearing capacity of group crushed-stone compaction pile were estimated. The more both single pile and group pile increase, the more yield bearing capacity tended to increase. Also, the yield bearing capacity of a group pile is about 50% less than the yield bearing capacity of a single pile. If the ground reinforced with the crushed-stone compaction pile is replacement ratio of $20{\sim}40%$, RIYB of both single pile and group pile increases qualitative tendency of linear more than original ground

• Journal of the Korean Geotechnical Society
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• v.22 no.11
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• pp.113-122
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• 2006

Although a number of static pile load tests have been performed in this country, re-consideration on the interpretation and loading method is needed, because of their less usefulness in practice. For this study, a static loading testing was performed for a long instrumented PHC pile, which was installed in sand layer overlying thick soft clay. The shaft resistance of the pile had been monitored for a long time after installation, and then the static load testing was performed by the quick load test, unlike the recent Korean practice. Using the measured data, the elastic modulus of pile, residual stress and true resistance on the pile were determined. In the event, it was found that the residual stress on the pile, which remained prior to the static loading, significantly affects the shaft and toe resistances. Also, it was realized that the setup effect for the long pile is significant.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.373-380
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• 2002

In this study, In order to compare the behavior of axail load transfer for S.L. coated piles and uncoated piles installed at a field test site. During static pile load tests, axial load transfer for S.L. coated piles and uncoated piles were measured.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1-8
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• 2005

In this study, static pile load tests for instrumented drilled shaft pile and instrumented driven steel pipe pile were performed. Based on the results of pile load test, skin friction of each stratum was compared. Skin friction of drilled shaft were more than those of driven pile at the same settlement. This was based on the difference of surface roughness of piles and pile construction methods.

• Geomechanics and Engineering
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• v.29 no.4
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• pp.407-420
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• 2022

Embedded piles, which are typically used in Korea, are precast piles inserted into prebored ground with cement paste. Dynamic pile tests tend to underestimate the bearing capacity of embedded piles because of the undeveloped shaft resistance prior to the curing of the cement paste and the insufficient energy transferred after the curing. In this study, a resistance combination method using the base resistance before the cement paste is cured and the shaft resistance after the cement paste is cured is proposed to obtain a combined load-settlement curve from dynamic pile tests. Two pairs of embedded piles with diameters of 600 and 500 mm are installed. Each pair comprises one pile for the dynamic pile test and another pile for the static load test. The shape of the load-settlement curve obtained using the proposed method is similar to that obtained from the static load test. Thus, the resistances evaluated using the proposed method at selected settlements are similar to those obtained from the static load test. This study shows that the resistance combination method may be used effectively in dynamic pile tests to accurately evaluate the bearing capacity of embedded piles.

• Advances in concrete construction
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• v.10 no.1
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• pp.49-59
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• 2020

Precast concrete elements in accelerated bridge construction (ABC) extends from superstructure to substructure, precast pile foundation has proven a benefit for regions with fragile ecological environment and adverse geological condition. There is still a lack of knowledge of the seismic behavior and performance of the precast pile foundation. In this study, a 1/8 scaled model of precast pile foundation with elevated cap is fabricated for quasi-static test. The failure mechanism and responses of the precast pile-soil interaction system are analyzed. It is shown that damage occurs primarily in precast pile-soil interaction system and the bridge pier keeps elastic state because of its relatively large cross-section designed for railways. The vulnerable part of the precast pile with elevated cap is located at the embedded section, but no plastic hinge forms along the pile depth under cyclic loading. Hysteretic curves show no significant strength degradation but obvious stiffness degradation throughout the loading process. The energy dissipation capacity of the precast pile-soil interaction system is discussed by using index of the equivalent viscous damping ratio. It can be found that the energy dissipation capacity decreases with the increase of loading displacement due to the unyielding pile reinforcements and potential pile uplift. It is expected to promote the use of precast pile foundation in accelerated bridge construction (ABC) of railways designed in seismic regions.

• Journal of Korean Port Research
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• v.10 no.2
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• pp.69-90
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• 1996

This study is related to save the bearing capacity from using Meyerhof formula namely, static mechanics formula with the S.P.T(N value) of the soft ground and is to choose the soft ground improvement method by the using of total load for the proper method of the pile foundation and then to design the most suitable pile foundation to fit the actual circumstance. The purpose of this study is calculating the diameter of the pile foundation by static mechanics formula and introducing the optimum design condition from the result of the bearing capacity for using N value of the S.P.T obtained from the deep soft ground about the piles such as P.H.C pile, pipe and cast-in-place pile of big diameter, etc. As above-mentioned, it is considered that the use of P.H.C pile or pipe pile is advisable on the synthetical investigation and that the selection of cast-in-place pile method is desirable in terms of the constructive safety and durability.

• Geotechnical Engineering
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• v.13 no.5
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• pp.145-154
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• 1997

Though the static pile load tests gives the mosts accurate estimation on the load carrying capacity of tested pile, it appears time-consuming and not economical. Many test methods using equipments, such as Pile Driving Analyzer(PDA), STATNAMIC, and Osterberg cell, have been introduced in Korea, and pile best using PDA has been gaining popularity because of iris fast and simple operation. Static and dynamic tests results on the piles installed in the granular coils were analyzed to investigate the effect of geometrical damping on the estimated load carrying capacity. It was found that the CAPWAP analysis without considering geometrical damping effect underestimates the pile capacity by 30~60% under certain conditions. It was observed that the underestimation of pile capacity by CAPWAP occurs on the piles installed in the water-borne granular boils by SIP methods. When Smith skin damping value(SSkn) greater than 1.0 sec/m is obtained in CAPWAP analysis, it may reflect the large possibility of underestimation of pile capacity. The introduction of the geometircal damping option in CAPWAP analysis gives reasonable pile capacity, compared with the static pile load test results, and reduces the SSb value under 0.7 sec/m.