Page 91 - Handbook GEOTEKNIK_Final_Neat

Piling Problems in Rock Problems of Slender & Long Pile in Deep Soft Soil

HAMMER
1. CRUSHING OF PILE HEAD WHEN THERE IS
ECCENTRIC HAMMERING OR PILE TILTING /
DEFLECTION DUE TO HARD OBSTRUCTION 2. LONGITUDINAL SPLITTING OR
OR INCLINE BEDROCK SPALLING OF PRECAST CONCRETE
PILE WHEN ENCOUNTERING HARD
DRIVING ESPECIALLY AT NON-
CHAMFERED CORNERS OR LOCALIZED
HONEYCOMB NEAR PILE HEAD

3. PROBABLE TENSILE CRACKS DUE TO
HIGH TENSILE STRESS WHEN THE PILE
SUDDENLY PUNCHES THROUGH THE
LOCALIZED SAND LENSE, ESPECIALLY
4. DISLOCATION / SEPARATION OF PILE WHEN DIESEL HAMMER IS USED OR
JOINT WHEN THE PILE ENCOUNTERING HIGH WHEN DROP OF HAMMER > 1m
TENSILE DRIVING STRESS
5. WHIPPING OR DISPLACEMENT
EFFECT OF LONG SLENDER PILE CAN
NOTES: RESULT IN LOSS OF FRICTIONAL
RESISTANCE IN STIFF STRATA (LESS
1. MOST OF THE “8” PROBLEMS LISTED CAN BE PROBLEM IF L/r < 100 )
MITIGATED BY USING LARGER PILES (L/r < 100) PLUS
COMPLIANCE WITH THE TECHNICAL REQUIREMENTS
AS SPECIFIED IN MS1314 PART 1 (APPENDIX A & C,
WORKMANSHIP & INSPECTION REQUIREMENTS etc.).
THESE PROBLEMS ALSO CAN BE MINIMIZED BY USING
LARGE HYDRAULIC HAMMER WITH SMALL DROP LOCALIZED 6. POSSIBLE LONGITUDINAL CRACKS
(<0.6m) SAND LENSE DUE TO EXCESSIVE TWISTING /
DEFLECTION WHEN THERE IS
2. PROBLEMS 2,3,4 & 6 CAN BE MINIMIZED OR DIRECTIONAL STABILITY PROBLEM
MITIGATED BY USING PRE-STRESSED SPUN PILES (L/r > 100)
WITH EFFECTIVE STRESS > 7 N/mm 2
3. PROBLEM 4 CAN BE EFFECTIVELY MITIGATED BY
USING PRE-STRESSED SPUN PILES WITH COLLAR /
COUPLE PLATES WELDED JOINTS

7. WHEN STRIKING HARD ERRATIC OR 8. EXCESSIVE DEFLECTION UP TO 2.5m
INCLINED BED ROCK, PILE TOE MAY BE HAS BEEN REPORTED FOR LONG
DAMAGE, CAN BE MITIGATED BY SLENDER PILE (L/r > 120) (DIRECTIONAL
PROPER “OSLO” POINT STABILITY), CAN BE CHECKED BY
USING CLOSED END SPUN PILES
DEFLECTION
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74 PUBLIC WORKS DEPARTMENT MALAYSIA GEOTECHNICAL ENGINEERING HANDBOOK 75