Using Water Jets to Sink Piling in Lake Bottom.

[DocHeb]

A prior poster had commented about using water injected through a pipe to help set posts into the lake bottom. I need to put in several pilings to support a dock, but my lake bottom is total muck. I was thinking of taking my tractor to the edge of the ice this winter, but if I go through!! I have pushed a 4 foot pole in with my hands without any difficulty. My wife says "why don't you just do what the neighbors did? I look over - his two-year-old dock is listing to port and starboard, and walking down it makes you look like a drunken sailor. I need to get some pilings down deep!!!.

Has anybody ever used this method? I'm thinking about bolting a "halo" of water pipe around the bottom of a 16 foot post, and injecting water as the post is pushed downwards. I could get water to the bottom of the post with a piece of shedule 40 galvanized pipe running parallel to the piling. When the piling is in, I think I'll be able to unscrew the Schedule 40, leaving the "halo" down at the bottom.

 

[Glenn9643]

I've never used that method to set pilings in water Doc, but I've drilled a small hole in a cap on the end of PVC with a hose fitting on the other end to jet a pipe under a concrete drive, about 20'. It should work OK if you have enough water volume.

 

[DocHeb]

Yes, your experience makes me think this is possible. They came around my neighborhood 5 years ago with directional boring rigs to put in fiberoptic cable. I talked with the guys doing the boring, they were running out to 300 feet with the borer, and inject water with some kind of lubricant. They had a directional head on the unit that allowed them to steer the pipe's direction. I don't need steering, I just need one direction - down.

 

[ronjhall]

Chris
I helped the guys at a marina where I kept my boat. You can drive post into bottom by using a water pump attached to a hose and 1 to 2 10' lengths of ¾ pipe. Cut end of pipe at a 45-degree angle. Attach other end pipe to hose from a pump. Set post in location desired. Work pipe with pump on around bottom of post. Moving it around to wash dirt out from around bottom of post. Depending on how much pressure pump puts out a post can be set 3 to 4' deep into bottom of lake. This system works best in soft bottoms like sand and mud. Same method can be used to remove post.
Finding a pump that puts out enough pressure and volume may be the problem.
The marina had a small barge with the 5 hp gas water pump on top. This allowed us to get close to the water and guide the pole into location.

 

[wroughtn_harv]

Here's what you need doc. Vac U Tron

Here's my suggestion. You rent a vac u tron or equivalent.

Now the way they pot hole for utilities is a pressure washer like wand dislodges soil and stone etc. The vacuum removes the dislodged soil and stone etc.

So if you place a tube like a concrete form tube you can find at your local box store down as far as you can in the muck. You then vacuum out the muck. You use the high pressure wand to excavate below the muck and remove the debris with the vacuum. When you're as deep as want and or can go then you place your piling and fill the tube with concrete.

As more and more utilities find their way underground we're going to evolve to the point of this form of hole digging being the standard. The high pressure wand will not nick cable sheath or cut into fiber cable like a shovel can.

In 1966 in a land far far away I was part of a team placing telephone poles through a swamp. We used fifty five gallon drums welded end to end with all the ends removed. Using hammers sledge type of course, we drove the drum down into the muck. We used our standard telephone spade and spoon to remove the muck from the barrels. When we had the top of the second barrel at waist-water level, one and the same, we placed a telephone pole in the cavity with the help of a crane. We then filled the cavity with rocks.

It worked.

It wasn't fun. Well, there was the time the snake came across the water at us like a snake will do, head first.

I don't know how many of us were religious at the particular moment in time. But we were of one spirit walking rapid like on that water. /forums/images/graemlins/grin.gif It was a lot more funny than fun though. Afterwards of course.

I do believe the vac u tron system will work for you in your situation. Probably the best friend you could have at the moment is the one who contracts out cable construction for the telco. /forums/images/graemlins/smirk.gif

 

[DocHeb]

You could probably do a Vac-U-Tron equivalent by pumping high pressure water to the bottom of the caisson, and simultaneously pump water out (along with the dirt) with a trash pump.

 

[Taylortractornut]

Chris I have a good friend that drives 6 inch Schedule 80 pipe in the Chert/shale rivers here. They use a 500 pound pile driver but on some they rent a small electric jackhammer and they have a 1 inch plate they cut to fit over the pipe. it has a flange on it to keep it from bouncing off the pipe. They have gone as deep as 6 feet per pole with this set up. They use the 120 outlet on the welder to run it but you can also uses a little generator Wer built one using a walk board firts sint 2 piles close to the bank then make our temporary scaffold an old swing set to hold the walk way up. We drove 2 more poles then put the header on it. We'd pick up the swing set it over and the wa its legs were spaced it would land just right to put another section down. We went about 90 feet in the river his way with 9 10 foot sections.

 

[BXMMCC]

I may have been the poster you're referring to. Depending on the length of the pile - you'd want a pipe about as long as the pile. If you weld, cut the jet end axially as if you were making a cross on the very end of the pipe, then hammer and weld it so that it's about half the original size. You want a jet affect, but you don't want to make the end any larger than the pipe diameter. You need a high volume low pressure pump, and you work it into the area where you're going to place the piling. After you sink the pipe all the way, and you see that you can raise and lower it easily, you then put the piling in the hole that you made. You put the thin end down. The weight of the pile will take it down quite a ways, but then you work the pipe around the pile to get it down further. Then you put a weight on the butt end to drive it all the way in. Keep the weight on , remove the pipe, DO NOT shut off the pump before the pipe is removed.
Don't know anything about WroughtNHarv's method, but the method I've tried to describe doesn't want any more material removed than is necessary to set the pile. Skin friction is the principle is use for bearing load.

 

[BWa]

Another angle at this problem is what is called an air lift , ,, take your 3-4" pipe and put a grid over it to keep rocks to big to go up the pipe and get stuck . Plumb that end with a shut off valve and hook that to an air compressor .
The way this works is you turn on air compressor open shut off valve this lets air in to the pipe the bubble floating up the tube make a suction that will increase the deeper you go in depth of water ,,, Just make sure you direct the discharge out of your way ....
This is an old treasure hunting tool works the same if water is jetted up the pipe to as in gold dredge ...
Bill G.

 

[DocHeb]

</font><font color="blue" class="small">( If you weld, cut the jet end axially as if you were making a cross on the very end of the pipe, then hammer and weld it so that it's about half the original size. )</font>

I'm conceptually challanged on this - any chance you could draw a picture?