Shoring....

[JD450A]

Right, 10' Square 4m deep in waterlogged ground below 1m, Fissure d Clay/Shale type material. Access facilitates a maximum machine size of 7.5t and the biggest lorry I can get in the access is my 15 ton SWB wagon.

Needs to be dug and left open for around 2 days to facilitate installation of a sewage plant.

I'm thinking sheet piles driven in with a EMV and braced.

Any other thoughts and Ideas. Initially I had hoped we would find more solid rock at 2.5m but it's shite at 2.3m (current trench depth) so using the steel sheet and prop shoring I use for trenching won't work. A box is too heavy to crane around with the 7t machine,likewise will be difficult to remove post excavation.

 

[Furniss]

Let someone else do that one

 

[JD450A]

Let someone else do that one

oh If only that was a option, I actually thought it might be happening yesterday evening but alas no.

This is actually the first job I'd happily not go to. Customer doesn't like mess but has for various reasons committed to doing it in the middle of winter oh and they worry substantially. Builder involved is cracking to be fair and as usual i'm just plant hire, but also as usual getting asked to come up with the solutions

It's a possible job, but needs proper shoring and pumps running 24/7 below the base level of the tank. If there was a sign of better ground we where going to weld in situ a box and cut it out at the end of the job. But s**t ground below 2m means we need piles.

 

[fred]

Whatever you decide on be bloody careful and have a rapid means of getting someone out of the hole fast.

 

[JD450A]

Whatever you decide on be bloody careful and have a rapid means of getting someone out of the hole fast.

Won't be anyone in the hole bar setting the props and removing them if all goes well. Concrete base can be poured outside and tank set in place from the surface. Then Mass pour concrete removing the shoring once it's up to a safe distance from the top of the hole. Probably throw some plastic sheeting down the sides of the piles to aid extraction.

It's a twat of a job, but someone has to do it.

 

[Furniss]

Sounds like a pita - but sometimes the jobs like that can go really well with proper planning and assuming the worst case scenario.
I find the ones I think are going to be a doddle are often the hardest.... which is must be the result of poor planning and mindset.

 

[JD450A]

which is must be the result of poor planning and mindset.

Builders You and I both know the craic.

This job was supposedly a easy one. But no one has taken into account the time of year, or depth. Plus we normally have rock/shale at below 1m which would work nicely and hold up safely for 48hrs to pour a base, site the tank and then mass pour.... But it's not so here we are.

That's before we get onto the subject of weather.... Middle of f****ng winter... we laid 50m of drainage run on this site at 1-2m deep in the heaviest rain of the year....

 

[DaveDCB]

Dewater it, or you’ll just be fighting it all the way.

 

[Furniss]

Builders You and I both know the craic.

This job was supposedly a easy one. But no one has taken into account the time of year, or depth. Plus we normally have rock/shale at below 1m which would work nicely and hold up safely for 48hrs to pour a base, site the tank and then mass pour.... But it's not so here we are.

4m bottom of dig .... what's driving the depth ?

 

[JD450A]

Dewater it, or you’ll just be fighting it all the way.

Already on it... got a sump to run from already installed at 2m... beyond that we will have to pile first then drop a well point in to depth in a corner whilst we dig.

4m bottom of dig .... what's driving the depth ?

Pipe invert is already at 2m and there is around 1.5m + bottom concrete pad below that. To get the water down it will need a temporary sump installed below the pad base.

 

[Furniss]

Already on it... got a sump to run from already installed at 2m... beyond that we will have to pile first then drop a well point in to depth in a corner whilst we dig.


Pipe invert is already at 2m and there is around 1.5m + bottom concrete pad below that. To get the water down it will need a temporary sump installed below the pad base.

2m deep ... is it picking up a few properties?

 

[JD450A]

2m deep ... is it picking up a few properties?

Feeds from two... but the pipe started at 1m deep at the old tank, and the new tank has been placed 60m further away. At the 1:60 fall specified that means a extra meter of depth

 

[Furniss]

Feeds from two... but the pipe started at 1m deep at the old tank, and the new tank has been placed 60m further away. At the 1:60 fall specified that means a extra meter of depth

Too obvious I know but I'll say it anyhow...You've checked falls on existing pipework to make sure you cant gain a bit by putting it to minimum falls ?

 

[Brendan]

Contact groundforce they use to do a free design service when your hiring their kit, better safe than sorry.
They should be able to sort you out with sheet piles and hydraulic pump out frames.

They do a vibration tool to set them in to save trying to batter them down with bucket, could also give them a little vibration to free them at the end of the job

 

[fred]

Feeds from two... but the pipe started at 1m deep at the old tank, and the new tank has been placed 60m further away. At the 1:60 fall specified that means a extra meter of depth

severntrent don’t like it but allow 1/pipe diameter when falls are hard to get. Would take a lot of depth out of that hole.

 

[Komatsu]

Will bell you tomorrow

 

[Lynchy]

As been said,get design off groundforce or mgf,can't go wrong then as long as it's installed properly,both also hire emv's,be better off with side grip movax,smallest ones for 8t I think,much more control and being able to bottom drive pentration

 

[JD450A]

As been said,get design off groundforce or mgf,can't go wrong then as long as it's installed properly,both also hire emv's,be better off with side grip movax,smallest ones for 8t I think,much more control and being able to bottom drive pentration

Cracking Lynchy.

 

[Lynchy]

Cracking Lynchy.

Just done eusr3/4/5 safe excavation,trying to sort piling nvq since firm I was on with supervisingwent bang,doing this sort of stuff 8 years,now being self employed again need bits of plastic to prove it

 

[Left hooker]

Mabey hire do design stuff for jobs like this
Would have thought you want ground ankors installed to put over tank due to wetness of ground