2. 말뚝재하시험 (Pile Test) -...

© Park 기초공학 lecture_05_pile_foundation

2. 말뚝재하시험 (Pile Test)

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2. 말뚝재하시험 (Pile Test)

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Elastic shortening of the pile

Pile Test

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2. 말뚝재하시험 –인발시험

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추정말뚝설계하중의 2 3 배에달하는하중재하


2. 말뚝재하시험 –수평재하시험

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추정말뚝설계하중의 2 3 배에달하는하중재하


Estimation of Allowable Load

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Types of LoadUltimate Load (also termed “plunging load”)

Yield Load = Failure Load = Limiting Load

도해법DavissonLoad @ 0.1 D

Allowable Load = Yield Load / 2 = Ultimate Load / 3


Yield Load: S-log t method

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Yield Load : dS/d(log t) - P method

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Yield Load : logP - logS method

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Yield Load: Davisson

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= PL/EA

Recommended byFHWA (1996)CGS (1992)DM-7 (1982)

4.0 610120

61030

DS D mm

D D mm


3. Pile Driving Formula

Pile Driving FormulaEquations to estimate the ultimate capacity of a pile during driving

Engineering News (EN) Formula

Energy imparted by the hammer per blow=pile resistance x penetration per hammer blow

Ru

W hQS C

Drop hammerC=25.4 mm

Steam hammerC=2.54 mm

FS = 6

Eu

EHQS C

E=Efficiency of the hammerHE=Rated energy of the hammer

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Pile Driving Formula

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Pile Driving Formula

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4. Dynamic Pile load test

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WEAP


Negative skin frictionDownward drag exerted on a pile by the soil surrounding it.Usually occurs only in clay/silts with N < 6

© 2004 Brooks/Cole Publishing / Thomson Learning™

Case 1 Case 2

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Shaft resistance

Negative skin friction

Opposite directionsConsolidation maximum at the top, decreases with depth


Negative skin frictionCase 1

0' ' tann v n uf K or f s

Case 2

1

1

' 2 '2 ' '

f f f f f fL H L H H HL

L

0' ' tann v n uf K or f s

0' 1 sin '0.5 0.7 '

K K

Neutral depthBowles (1982)

-침하해석

-경험식마찰말뚝이나불완전지지말뚝; 0.8L보통의모래, 모래자갈층에지지: 0.9L암반이나굳은지층에완전지진된경우: 1.0L

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2. 말뚝재하시험 (Pile Test) -...

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