pile driver- a machine that drives piling into the ground machine- any mechanical or electrical device that transmits or modifies energy to perform or assist in the performance of human tasks Based on WordNet , Farlex clipart collection. © Princeton University, Farlex Inc. Translations paalujuntta keihardkrachtig копёр.
The Pile Driving Analyzer® (PDA) system is the widely employed system for Dynamic Load Testing and Pile Driving Monitoring in the world. High Strain Dynamic Load Tests, also called PDA tests, assess the capacity of several piles in a single day. Pile Driving Analyzer systems also evaluate shaft integrity, driving stresses, and hammer.
Definition of pile driver: a machine for driving down piles with a drop hammer or a steam or air hammer Examples of pile driver in a Sentence He hit .
Urban Dictionary: Pile Drive pile drive helicopter Sex position where a woman would do a tripod hand stand (resting on her head and palms with her knees on her elbows) while the man is inserted while laying facedown with arms and legs splayed out.
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Learn about our editorial policies Updated on November 20, Pile driving is often a cost-effective and time-efficient method of driving support posts piles into the earth. But because you’re working with soil and other hidden features in the earth, there is an element of the unknown, and things don’t always go as planned.
Whether you are driving concrete, steel, or wood piles, any number of problems are common. Not surprisingly, problems with pile driving usually are related to adverse or unexpected soil conditions, which can lead to pile damage, hammer-pile alignment problems, and other issues. Confirm that the pile has sufficient drivability and that the driving system is matched to the type of pile.
If no obvious problems are found, take dynamic measurements to determine if the problem is related to the driving system or to soil behavior. Driving system problems could include preignition, preadmission, low hammer efficiency, or a cushion that is too soft.
Possible soil issues can include greater soil strength than anticipated, temporarily increased soil resistance with later relaxation this requires a restrike to check , large soil quakes, or high soil damping. Perform restrike tests after an appropriate waiting period to evaluate soil strength changes. If the ultimate capacity based on restrike blow count is still low, check the drive system performance and restrike capacity, using dynamic measurements.
If the drive system performance is as assumed and restrike capacity is low, the soil conditions are probably weaker than anticipated. Foundation piles will probably need to be driven deeper than originally estimated, or additional piles will be required to support the load.
For piles that allow internal inspection, reflect light into the pile toe and inspect for indications of damage. For piles that cannot be internally inspected, take dynamic measurements to evaluate the problem, or consider pile extraction. Perform restrike testing. Establish the setup factor, and drive to lower capacity.
Hammer performance may also be better than anticipated, so this should also be checked. If they do not indicate soft layers, the problem may be that the pile is damaged below grade. If the pile was spliced, re-evaluate the splice detail and field procedures for possible splice failure. Investigate both tensile stresses along the pile as well as compressive stresses at the toe. Possible solutions include redriving the installed piles, changing the sequence of pile installation, or predrilling the pile locations to reduce ground movements.
Lateral pile movements can also be caused by soil failure in the adjacent slope. If due to poor hammer-pile alignment control, a pile gate, template, or fixed lead system may improve the ability to maintain alignment tolerance. Soil conditions, such as near-surface obstructions or steeply sloping bedrock having minimal overburden material, can also disrupt alignment.
If due to poor hammer-pile alignment control, a pile gate, template, or fixed lead system may improve the ability to maintain location tolerance. If the obstructions are at deeper depth or below the water table, or if the soil is contaminated, excavation may not be feasible.
In these cases, spudding or predrilling of pile locations may provide a solution. Ultimate bearing capacity of piles hitting obstructions will need to be reduced based on pile damage potential and soil matrix support characteristics. Additional piles may be necessary to compensate. If the alignment appears to be normal, the combined tension and bending may be too high.
If the calculated stress is high, add pile cushioning. If the calculated stress is low, possible causes are inferior pile quality, hammer performance, and hammer-pile alignment issues. If the calculated tension stresses are high, add cushioning or reduce the length of the hammer stroke. If the calculated tension stresses are low, the cause may be hammer performance. If the calculated tension stresses are high, consider using a heavier ram. If the calculated tension stresses are low, take measurements and determine the quakes, which are probably higher than anticipated.
If the alignment appears to be acceptable, then combined tension and bending may be too high. If the calculated stress is high, reduce the hammer energy stroke for low blow counts; for high blow counts, a different hammer or pile type may be required. Compare the calculated and observed blow counts.
If the observed count is lower, it’s likely that the soil resistance is less than anticipated. If the blow counts are comparable, reanalyze with lower combustion pressure to match the observed hammer stroke. When this is the case, you can Increase the pile impedance or material strength, or redesign for lower capacities.
If the soil is fine-grained or known to exhibit setup gains after driving, the end-of-driving capacity may be selected to be lower than required. Confirm the capacity by restrike testing or static load testing.