Retaining Walls

[netherla]

Our new house (in Michigan) is under construction, and the site plan calls for two retaining walls. We were planning on having a landscaping company build the walls out of bolders. However, the price for both walls installed is $20K. I am wondering if my Kubota B1750 with front end loader would be able to lift those large rocks. The top of the wall may be as high as 7' in places, and the total amount of bolders is about 100 tons. Anybody have experience doing this?

 

[daschluck]

Hello, I am from Michigan also. St. Charles area. Here is a picture of my retaining wall. It is about 6' at its tallest. I have used about 13 ton so far at a cost of about $1000. I am using an L3010 tractor with absolutely no troubles. You may have to just lift fewer boulders at a time. I am filling the bucket with no hesitations whatsoever.

Regards,

Dennis

 

[daschluck]

One other word of caution. I had an cement drive slab that tapered to 1 corner. Tried to build this wall there and it completely washed out all the boulders in the corner. So I ended up pouring a cement "trough" (I guess for lack of a better word) and that seems to have solved my erosion problem on the corner. The rest of the wall has held up very well for a year now.

Just something for you to consider.

Dennis

 

[Boondox]

I had a b1750 also and found it was unable to lift even moderately large boulders. In fact, it struggled with loads of rock maple. The weakness of the FEL was the primary reason I traded up to an L3010 (which I absolutely love!). I guess the best advice I could offer would be to find a few boulders of the size you intend to use and give it a try. Also, you didn't mention the tire type you're running. Turfs aren't made for that sort of work, but you can get away with fairly heavy loads by running at the upper end of the inflation specs.

$20k is a lot of money. Could you rent a bigger tractor for a week?

Pete

www.GatewayToVermont.com

 

[MarkV]

James, If you take on the project, make sure you have a good counter weight hanging off the back. Big rock lifted 7' needs some weight in back to keep you on the ground. Let us know how it goes.

MarkV

 

[StoneHeartFarm]

Do the retaining walls need to lay on the dirt say at a 45 degree angle, or do you need something more vertical? Do you insist on larger rocks, or can you use smaller, more "MAN"agable rocks? Here's a picture of my wall under construction. All lifted by hand. The finished wall will be about 130-150 feet long, 3 tiers high in places. The section you are seeing is about 20' long and is 5-6 feet high.

There are 2 keys. 1. Good footing below the frost line. 2. Wall must be THICKER at the TOP.

To accomplish #2, Build the wall a couple of feet high at a time (you can't cement much higher than that in a day anyway), place a wooden form behind and pour in a Stealth Fiber reinforced cement.

Hope this helps.

 

[scruffy]

For 20K, I would think about investing in the L3010 and building myself!

 

[mlmartin]

It really depends on how vertical a wall you are building. If you are trying to retain an existing grade with rip/rap or boulders, you should be able to size your boulders to the lifting capacity of your FEL and drop them in place. This kind of retaining wall is really just doing erosion control.

If you are going to back fill behind a nearly vertical wall you might just want to size your boulders to what you can lever and pivot them by hand. In this case you are building a structure.

I've built 1 1/2 dry laid retaining walls by our new bank barn. They are both structures. The first one was hand laid above ground. The foundation boulders were laid by the excavator. It's about 8 1/2 feet at the highest. The 1/2 wall is (still) under construction. I dug out and placed the foundation stones with my JD870. Many of the larger boulders were lifted to wall height with the FEL, but I positioned them by hand. I can lift and place stones up to nearly 200 lbs by hand, but I can position stones up to 500 lbs with pry bars and by pivoting.

I have some 800-1000 lb boulders to go into the rest of the retaining wall. I will be placing them with the FEL bucket using chains and positioning them at the bottom of the wall with the backhoe. This takes a careful hand and a lot of patience. As I progress upwards I will use the FEL for lifting and hand tools for positioning.

If you're building a dry structural retaining wall, you might want to consider what happens if the structure fails while you're working on it. That's the time that it is the least stable. It's pretty dangerous work and part of the $20,000 they are charging is for their experience in doing it right.

Matthew

 

[StoneHeartFarm]

Matthew,

It's also going to depend on the soil. One thing Michigan has is a lot of beach sand. I tried dry laying my retaining wall. Got it up about 6' high and it looked real nice. Then one day I was out in back picking rocks and the plumber showed up. "That's too bad about your wall", he said.

Needless to say, the sand backfill had dried out and while I was back picking rocks, it had spilled (flowed like water actually), starting at the top and working about 1/3rd of the way down the wall, taking all that work with it. Good thing I wasn't standing in front of it at the time. /w3tcompact/icons/crazy.gif That's when I decided cement might be a good idea. I don't have enough of the great big rocks to do any good and the few I have I want to use for anchoring at corners. I do have about half a million the size of basketballs. So, I have a cemented, "random rubble pattern" wall. It's really not too hard to do, kinda fun, and you don't need a gym. I keep tellin folks to quit paying those high priced gym fees and just come to my Health Spa (we don't use the term forced labor camp anymore/w3tcompact/icons/laugh.gif). Shoot, for 1/2 of what they're paying for gym fees, they can come see me and I'll let them stack and haul rocks and swing the shovel. Both strength and aerobic training at a discount price. /w3tcompact/icons/laugh.gif /w3tcompact/icons/laugh.gif

 

[mlmartin]

Soil does make a great deal of difference, as you say. The area around my barn is pretty loose gravel, so I have my retaining walls raking back. While the rake is uneven it averages 5 degrees or so.

Another very important issue is grade. If you're building a dry laid retaining wall the top of the wall must be the highest part of the grade or the wall must be very thick. Allowing water to run over the top of the wall is a sure fire way to have it fail. Last weekend we got 2.75 inches of rain in an hour. It wiped out 6 feet of my "under construction" wall because the grade allowed the water to run down the wall (my 6 inch high dike was overcome).

One nice thing about dry laid walls, though, is that they inherently drain. That can be a real problem with solid walls.

Matthew