Dewatering dramas
This will be short and sweet and is a bit of praise for John Moran.
Situation – JHG have created a cofferdam and have a dewatering plan
Issue – It isn’t working
Serevena becomes involved and asks 3 questions:
1. Where is the flow net? Do we know/understand the flow path?
2. What is the ground all about? Where are the bore hole logs? Do we know the permeability?
3. What is our pump capacity? What are the depth of our sumps?
Answers to the above:
1. Don’t have one and therefore no understanding.
2. It doesn’t matter as the water leaking through the pile clutches is the biggest factor.
3. Not sure, very deep.
So, Serevena has an epiphany and remembers all about flow nets and groundwater control. Ex Cofferdam was worthwhile!
So I ask the senior project engineer about this. He tells me to get back in my box and that all we need to do is lower the sumps. That was the last plan and it didn’t work. Until now we have been undertaking trial and improvement. This is going to change now, and I will make it happen!
John, do you fancy a bit of consulting work???
Holdfast Training Services Trial Blog 
Sure JM will pick up on this so will be brief – have you got a conceptual model? Your questions are all spot on and you could of course add where’s the water table/what is the driving head to them. If you can sketch out a simple line diagram of the arrangement, put some assumptions to it and look at the known figures then you will be half way to having an engineering understanding and a fair guess at what is probably going on. Send this through either by email or as an attachment to the blog. The return would have to be by email because we cannot attach to comments so unpdates here for the interest amusement of all would be an adjunct.
Availbe for parties and bar-mitzvahs at loww ..loooow prices
You’re the third of your crew that have been faced with gorundwater issues
Sad to say , I won’t see a consultancy fee as you are well capabe of working through the sort of problem you describe..
If the clutches are open the pile line is an equipotential at zero pressure…