Study on the Applicability of Dynamic Pile Load Test to Check Integrity during Installation of Extension Plate Attached PHC Piles and Bolts Spliced PHC Piles and the Correct Proof Test of the Transformed-installation PHC Piles

Myunghak Kim; Yongkyu Choi

doi:10.7843/kgs.2018.34.12.115

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Research Article

Study on the Applicability of Dynamic Pile Load Test to Check Integrity during Installation of Extension Plate Attached PHC Piles and Bolts Spliced PHC Piles and the Correct Proof Test of the Transformed-installation PHC Piles 확장판 선단부착 PHC말뚝 및 볼트 수직이음을 사용한 PHC말뚝의 시공 중 건전성 확인을 위한 동재하시험의 적용성 및 변형시공법 PHC말뚝들의 올바른 검증시험에 관한 연구

31 December 2018. pp. 115-131

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Abstract

Extension plate attached PHC piles and bolts spliced PHC piles were installed in field test site. Pile integrities were checked during installation with dynamic pile test and the actual pile conditions after installation were compared with integrity index (β index) by PDA test. Theoretically the break in near pile end or pile end (especially extension plate itself) was very difficult to access by integrity index (β index) and also require a high level of knowledge and field experience on PDA test. First actual wave equation of bolts spliced PHC piles due to bolts spliced equipment can be different with welding spliced. Second wave length of the stress wave from installing can be longer than the height of bolts spliced equipment (about 100 mm). Third Beta processing in PDA analysis function is very difficult to access without a high level of knowledge and field experience on wave equation. Above-mentioned three reasons can make conclusion that traditional PDA test in domestic site can not access the integrity of bolts spliced equipment in bolts spliced PHC piles.

Keywords

Extension plate attached PHC pile

Bolts spliced PHC pile

Pile integrity during installation

Dynamic pile load test

Integrity index (β Index)

Wave equation

Access pile integrity

Bolts spliced equipment

현장 시험 부지에서 확장판 선단부착 PHC말뚝 및 볼트 수직이음 PHC말뚝에 대한 시험시공을 실시하고 시공중 건전성을 동재하시험으로 확인하고 시공 후 말뚝의 건전성을 직접 확인하였다. 그 결과를 분석하여 확장판 선단부착 PHC말뚝 및 볼트 수직이음 PHC말뚝의 시공 중 건전성을 동재하시험의 건전도지수(β지수)로 평가할 수 있는지에 대하여 연구하였다. 이론적으로 말뚝 선단에 매우 인접하거나 선단끝단에서 발생하는 손상(특히 확장판 선단부착구 자체의 변형)은 시험기술의 특성상 건전도지수로 정확한 평가하는 데에는 한계가 있었다. 말뚝의 선단부에 바로 인접해서 발생하거나 말뚝선단 끝단에서의 손상을 PDA시험을 통하여 명확하게 평가하는 데에는 시험기술의 이론에 대한 고도의 지식과 경험이 요구되었다. 다른 볼트 수직이음구로 인하여 실질적인 1차원 파동전달이 용접이음에서와 다를 수 있다는 점, 타격에 의해 발생하는 응력파의 파장이 볼트 수직이음구 높이(약 100mm)보다 클 수 있다는 점, PDA 분석 기능 중 베타 프로세싱(Beta processing)이라는 기능 등이 매우 심도 있는 지식과 경험을 토대로 평가해야만 더욱 정밀한 판단이 이루어질 수 있다는 점 등을 종합적으로 고려할 때 일반적인 건전성 평가기술로 볼트 수직이음의 건전성을 평가하는 데에는 한계가 있었다.

References

Choi, Y. and Kim, M. H. (2018), Axial bearing characteristics of tip-transformed PHC piles through field tests, Journal of KGS, Vol.34, No.11, Nov. 2018, pp.107-119. (In Korean)

Kim, M. H. (2018a), Safe installation method development project for extension plate attached PHC piles and bolt spliced PHC piles(Final report), Inje University industry academic cooperation foundation, pp.1-341. (In Korean)

Kim, M. H. (2018b), Safe installation method deveropement project for extension plate attached PHC piles and bolt spliced PHC piles (Final report) - supplement, Inje University industry academic cooperation foundation, pp.A-1-1~A-13-48. (In Korean)

Kim, M. H. and Choi, Y. (2018), Comparison of splices between bolts and welding spliced PHC piles, Journal of KGS, Vol.34, No.12, Nov. 2018. (In Korean) (in process)

Likins, G. and Rausche, F. (2014), Pile Damage Prevention and Assessment Using Dynamic Monitoring and the Beta Method, Soil Behavior Fundamentals to Innovations in Geotechnical Engineering, ASCE Geo-Institute Geotechnical Special Publication No.233, pp. 428-442.

Pile Test Corp. (2018), Dynamic pile load test report for second open PHC pile field test to check pile performance, Report No. KJ1805R01, 2018. 8, pp.1-32. (In Korean)

Information

Publisher :The Korean Geotechnical Society
Publisher(Ko) :한국지반공학회
Journal Title :Journal of the Korean Geotechnical Society
Journal Title(Ko) :한국지반공학회 논문집
Volume : 34
No :12
Pages :115-131
Received Date : 2018-12-01
Revised Date : 2018-12-18
Accepted Date : 2018-12-20
DOI :https://doi.org/10.7843/kgs.2018.34.12.115

Journal of the Korean Geotechnical Society ISSN:1229-2427(Print) 2288-646X(Online) 한국지반공학회 논문집

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