we are installing 7m long kkd8 sheet piles to a depth of 6m in the ground for a basement dig out, using a vibrating hammer on a 22 ton jcb.
so the problem, we've installed 70 so far and got 50 of them down to refusal at the required 6m. however the remaining 20 have stopped driving and we have shredded a few of the tops. (8mm thick steel broken like it was paper) at about 4m down.
the basement dig will be 3m down so we need to get them down to the 6m, so 3m in the ground supporting the exposed 3m we are digging out.
we have dug done to a depth of 6.5m and the strata is gravel/clay sand then at 3m down there is a 400mm layer of very dense clay with small aggregate in it that we have passed through with ease. below that is clean sand, i mean very clean sand.
the problem is the sand is so dense it harder than concrete, so the piles are bouncing and destroying themselves. the hammer is working fine as you can feel the vibrations 400 yards away. we've lost 2 mugs from the brew room already.
has anyone got any ideas what to do apart from getting a bigger hammer or pilling rig.
photos:
Giles
Groundworks and Equestrian specialists, prestige new builds and sports pitches. High Peak, Cheshire, South Yorkshire area.
can't get a bigger rig in, its a private road that was once a park, there is a set of huge stone gate posts that are only 2.5 metres wide the 220 just fits through and had to track it down off the main road. mgf recommended kkd6 6mm piles we went for the 8mm ones. amazing how tough sand can be.
Giles
Groundworks and Equestrian specialists, prestige new builds and sports pitches. High Peak, Cheshire, South Yorkshire area.
never used one myself but you could try a TOSA or a still worker pile driver. these are quieter, less vibrations and I think they would help as they are not like an EMV in that they dangle off a machine but they are clamped onto the neighbouring pile. they are used a lot where piling is close to old or existing structures
Fussey piling or sheetpiling UK will help try their websites. I would post a link but...its friday afternoon.
bigger piles probly not needed 8mm is plenty thick enough. I hope the EMV is on a hired machine too with all that shaking...the one that I have used before was a krupp on a JS130 hired from piletec. they sent a fitter out to change the valve block over and "plumb it in" so it could be operated on the bucket ram basically.
BTW on one job where we were specified to use Larssen 603 piles (I think) they all met refusal at about 2m. this was in eltham se london, on lewisham sand===v dense. the upshot was overnight the design changed from driven to bored piles. this was a basement too, I can post photos if you like.
so spoke to a guy who runs a pilling company and he advised auger down in front of the pile and blowing compressed air into the ground as they were being driven, so dug a 2 metre wide trench out and got our 3 ton in with our auger and 2 metre extension piece getting down to 3.3 metres below the level we were at so almost 6 metres, then air lance in and drive the piles got them all in. will post some pics tomorrow off to the pub now haha.
yes its on a hired machine, the whole site has been vibrating for a week haha.
we tried flooding the piles, digging a trench in front of them and leaving the hose running all night didn't penetrate the ground though.
Giles
Groundworks and Equestrian specialists, prestige new builds and sports pitches. High Peak, Cheshire, South Yorkshire area.
nice one GB glad to see you got them all in with just a little extra hassle
pling pics for dave
JS130 with krupp hammer
EMV on stand
Made all the more difficult because we were indoors
Mavis, my foreman (we call him that because he is an old woman)
look at the roller door stuff overhead...pain in the ar5e or wot?
then once all piles were in, cut oles in them and welded on brackets for strongback
Platipus anchors driven in using pecker on 7 tonner, and cables tightened up. All this was for a 4 foot deep swimming pool, part of a JJB sports fitness club. The piles went in because the edge of the pool was 1m away from the block wall that you can see in the photos. The line of the piles is crooked because we had to kink in the middle around the staunchion base
closer look at platipus anchor business end...clever stuff
top photos (sheet piling) are in Canterbury my home town,
basement pour photos are in Bromley south london. The project was a Big Yellow self storage warehouse
