BIG ROCK PROBLEM????

[dirtworksequip]

CHARLZ, good points on the support. I may try and move it again if the ground freezes. Right now its rainy and just too soft and muddy.

Do you think some concrete piers would work? I could auger 9 inch holes into original ground and then place Quik-Tubes or Sono tubes and pour concrete. I may even be able to get an extension for the auger and go another 18 inches. About 4 feet in the ground with the rest of the pier above the existing grade. Then fill with dirt above the piers(to protect the piers while resetting rock) and try to get it set back into place.

 

[pat32rf]

I don't think that 8" sonotubes are going to give you much in the way of lasting support, especially if there is any clay content to the soil. Just finished a 10x16 deck, the bldg dept wanted minimum of 4-ten inch tubes, down to below frost(48") in clay soil. You can get a new style tube called a "Bigfoot". Shaped like an upside down mushroom, about 4 times the support area.
Don't suppose it gets cold enough in your area to freeze that pond?

 

[dirtworksequip]

Pat32rf, yes the pond will freeze some winters. Thanks for the heads up on the 8" tubes. What about pouring 8 or 10-8" tubes and then placing some sheet steel (4'x8')on top of the piers with the rock sitting on the steel sheet? Just a thought. Do you have any other ideas as far as getting it to stay where I reset it?

 

[EddieWalker]

I'm wondering about the practicality of using tubes. Your flat rock sunk in the groud from it's weight. With all that surface area, it sank. This really boggles my brain, and I'm not getting how a sonotube is going to do anything. I don't understand what you'd do with a sonotube?

They are for bringing concrete above grade. If you drill some post holes and fill them with concrete, then what will this accomplish? The flat rock sank in the ground with all it's surface area. What will a few sonotubes do? Where will you put them?

OK, the rock sank. The rock is flat and it sank..... The rock has allot of surface area and it sank....... I think you need more surface area.

You have the trackhoe. Why not dig a trench perpendicular to the rock. Make the trench go under the rock and extend it out into the field on either sides. I'd got two feet deep. Then I'd dig another trench just like the first one, but four or six feet away from the first. And to finish it off, dig three more trenches connecting the ends and middle to creat an sqare looking 8.

Put in plenty of rebar and tie it all together. Pour concrete to within four inches of grade. Let it dry for a week or two, then push the rock on top of it. Cover the rest of the concrete with dirt and smooth it out.

The bigger you make the 8 shaped footing, the more weight it will hold. The more surface area, the more strength.

Good luck,
Eddie

 

[charlz]

Yeah, concrete 'tubes' would just get driven into the ground unless they go down to something solid, like bedrock. If you think about it all you are doing is taking the wieght on the top of the tube and moving it to the bottom. If it is the same type of soil/dirt it won't help any. The 'mushroom' mentioned above might help.... but then I am not an Engineer so take all of this with a bag of salt

With the abutment I was thinking more of trying to keep the rock from eventually tipping and sliding into the water. The dirt under the overhang has a place to go.. down and out. Couple this with erosion from rain water, melting snow etc. and I don't think it would take all that long based on what the soil looks like in the pictures.

As Eddie noted if keeping the whole thing from sinking is a concern you probably need to take that weight and spread it out over a larger area. Really depends on your soil, it may settle some and thats it. But I think it would always be prone to sliding down into the water without something to keep the dirt under it.

Charles

 

[CurlyDave]

If you think about it all you are doing is taking the wieght on the top of the tube and moving it to the bottom.

Actually piers work on a different principle than footings.

With footings the weight is transfered to the earth by compression of the soil under the footing.

With soft soils, piers must be used. The force is transmitted to the earth by friction on the sides of the piers.

While I understand why dirtworksequip wants the rock where he has it, I am not convinced there is an economical way to do this.

If the soil is too soft, short concrete piers will not do much good, they will just increase the weight which must be supported. Similarly, a steel plate will increase the weight. Now if the plate is larger than the rock, then you might spread the load, but I think it will take a pretty large plate to produce a solution which is stable over time.

I suspect you need to talk to a soils engineeer, and then a civil engineer.

 

[BTDT]

Once you get the rock out of the way, put down 4 piers however deep you can get them. Two as close to the edge as you feel comfortable, then 2 back about where the back end of the rock will be. The top of these need to be below grade 6 or 8 inches. Then get you some steel I or H beams that extend a couple feet out in front of your piers near the water, and 6 or 8 feet behind the end of the rock. Fill dirt around beams, the top of which should be a couple inches out of the dirt. Put rock on top of beams and push toward water till it gets where you want it. Then cover and fill in as needed to hide beams and close gap around rock.

 

[dirtworksequip]

Thanks, guys for the suggestions.
Eddie, I understand what you are saying about the figure 8 footing, but I'm not sure that there will be enough area out on the peninsula for it. I'll keep that in mimd as an option though. Also have to figure the cost of the concrete. If I want to spend that much. Maybe curly dave is right. No economical way of doing it.
I was going to auger the holes and then pour the piers to the grade I needed the bottom of the rock to be. Which is slightly above the existing dirt grade. The dirt gets lower the more I mess with the rock.Then fill and compact the dirt to just above the top of the poured tubes. I thought the multiple tubes would give more bearing strength to what the rock was setting on. Maybe I just need to forget it though.
I don't know that the rock really settled or the ground towards the front eroded away and caused it to settle.


What does anyone think about digging a footer 3 foot deep and then compacting crusher run stone in the footer ditch. Would that give it more support than just dirt?

Keep the suggestions coming. I appreciate everyones imput. Thanks again!

 

[Regal]

The force is transmitted to the earth by friction on the sides of the piers.

I agree with what Curly Dave says, however, I think that if you move the rock and pour piers, when you try to slide the rock back into place it will exert too much side push on the piers and possibly cause them to crack or break off. Raising the rock and pouring piers would be best but don’t know how you could dig holes with rock in the way????
This is one of those times your “between a rock and a SOFT spot”

 

[charlz]

CurlyDave/Regal,

Thanks for the info on how piers work, I hadn't thought of friction on the sides.

Maybe the thing to do is re-work the rock and dirt the way you want it and then figure out if it is settling or tipping or whatever. Might be that it moves so slowly we will all be gone before it becomes a problem

So how would your figure that out? Drive in some rebar here are there around the rock that are level with the top/bottom or some chisel mark so you can reference this in a year or so and see what is going on?

This way you would know wether or not you have a problem before deciding to spend $$$ to fix it.

Charles

 

[Egon]

Drill a few test holes around were the rock will sit but do not move the rock. This should tell you what the soil conditions are and then you go from their.

Done properly you will have the rock on some beams when you slide it back in place. Then jack up, remove beams and lower in place.

 

[Regal]

How about, after the rock is out of the way, use the hoe to dig entire area down to natural then fill hole with rock, compacting as filled and lining the slope on pond side with rip-rap to reduce smaller rocks from eroding or sliding. Then slide rock back into place. This way you have an entire footing under the rock and should be much less costly than concrete.You could use timbers or steel runners to assist in the slide.
All this, providing there is access getting a load of rock delivered to the site.

 

[Torrak]

This rock is just like a giant teeter-totter. You can either lift the overhanging side up and try to brace it, or you can dig down behind the other side and push it down to become level.

I think it would be 100 times easier to dig underneath the "earth" side of the rock to bring it level. If you dig down you may have to pull the rock back to make it level.

Either way, it looks like that bank may be susceptible to erosion and eventually it would be come unlevel again unless you remove the rock and build up the foundation.

I think in this case it is 6 in one hand, half dozen in the other and leaving it the way it is looks better and better the more I think about

 

[dirtworksequip]

Thanks for all the input and suggestions. I'm sure that with using a little bit of everybodys ideas I can eventually get it moved out of the way,build something for it to set on and then get it reset the way I would like it. I'll update the post when I do anything else. Right now its rainy and muddy, so it may be awhile before I am able to go at it again. Thanks again!

 

[BTDT]

Thanks for all the input and suggestions. I'm sure that with using a little bit of everybodys ideas I can eventually get it moved out of the way,build something for it to set on and then get it reset the way I would like it. I'll update the post when I do anything else. Right now its rainy and muddy, so it may be awhile before I am able to go at it again. Thanks again!

I was wondering if all the rain had caused it to slide off into the water. I don't remember reading where you are located, but in North Texas, we finally got a decent amount of rain this last week.

 

[dirtworksequip]

BTDT, located in the N. Panhandle of West Virginia it has rained here for 4 days straight.(I sort of wish it had been snow. At least I could play with my tractor) The rock is not going anywhere right now on its own or with a machine. I got it pulled back far enough that its in no danger of slipping into the water. Looks like it will be spring before I tie into it again. I'll post some pics when I get it moving again.