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Driven pile set criteria - different expressions
- Thread starter GeoBo
- Start date
You have to establish you acceptance criteria. You could establish as many as you want as long as they mean "the same" with respect to acceptance.
You can say, 40 blows max or 12 blows/ft or any other criteria that you decide would work for your piles/soil.
You can say, 40 blows max or 12 blows/ft or any other criteria that you decide would work for your piles/soil.
vulcanhammer
Geotechnical
The best way to answer the question "Can I say they are the same?" is "Not really."
Let me explain it in US units, as I'm more familiar with the problem there.
Let's assume that we have a refusal criterion of 120 blows/ft. In theory we could also say 10 blows/inch; however, if we're driving to a dense/hard layer, the decrease in set may take place within the span of the foot. So the set could decrease substantially from the point where the pile toe entered the foot in question to where it left (or driving stopped.) Different sets imply different pile ultimate capacities, so whether you're using an inch, foot, 25 mm or 300 mm could make a difference.
How much of a difference it makes will depend on how much the soil profile varies. That's a job specific decision, but it's one that needs to be adhered to consistently once it's determined.
Let me explain it in US units, as I'm more familiar with the problem there.
Let's assume that we have a refusal criterion of 120 blows/ft. In theory we could also say 10 blows/inch; however, if we're driving to a dense/hard layer, the decrease in set may take place within the span of the foot. So the set could decrease substantially from the point where the pile toe entered the foot in question to where it left (or driving stopped.) Different sets imply different pile ultimate capacities, so whether you're using an inch, foot, 25 mm or 300 mm could make a difference.
How much of a difference it makes will depend on how much the soil profile varies. That's a job specific decision, but it's one that needs to be adhered to consistently once it's determined.
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