For those planning on building a pond here is a link to a very good information page about soil compaction. After building a pond and it leaks almost always soil compaction of the dam and or side walls is/are the reason. Important Note To Remember:
It often costs almost as much or more to fix a leaky pond as it cost to build the pond. Do it correctly the first time and you will save money and reduce a lot of later problems and headaches. Plus your pond will always look a lot better when fuller of water.
Page is from this thread:
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=389185#Post389185Discussion of homemade test to check if soil is compactable and will hold water if the pond is built correctly.
The Bucket Test
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=466870&page=1PROPER CONSTRUCTION EQUIPMENT FOR THE GOOD AND BEST COMPACTION
Sheepsfoot rollers can exert approximately forty times more pressure than rubber-tired equipment and are often specified where a high degree of compaction is needed.
Optimal compaction is obtained by using thin layers of soil, each about 6 inches thick. Thicker layers are not desirable, as the pressure transmitted to the soil decreases with soil depth.
https://extension.missouri.edu/g1555Note later it says when compacting with a bulldozer the soil thickness layers should be just 2"-3" thick.
A quick summary of PSI from tracked vehicles online. This is from a Hitachi Ex200, 20 ton excavator. The weight is probably twice your dozer but tracks are also larger. You can plug the numbers in from your dozer. In this example despite 20 ton weight the force on your boot is only 7 psi. It would be interesting to substitute the track area vs weight of your dozer. But either way, the PSI from a dozer tread has come up in other threads and the force generally per square foot is not much different than rolling it with a lawn tractor pulling a drum filled with concrete.
Here is the example from the web:
Ground Pressure
Ground pressure is the pressure exerted on the ground by the tires or tracks of a motorized vehicle, and is one measure of its potential mobility,[1] especially over soft ground. Ground pressure is measured in pascals (Pa) which corresponds to the EES unit of pounds per square inch (psi). Average ground pressure can be calculated using the standard formula for average pressure: P = F/A.[2] In an idealized case, i.e. a static, uniform net force normal to level ground at Earth sea level, this is simply the object�s weight divided by contact area. The ground pressure of motorized vehicles is often compared to the ground pressure of a human foot, which can be 60 � 80 kPa while walking or as much as 13 MPa for a person in spike heels.[3]
Note later it says the ground pressure of a sheepsfoot roller is 1400 to 7000 kpa ! One KPA is equal to 0.145038 PSI.
Increasing the size of the contact area on the ground (the footprint) in relation to the weight decreases the ground pressure. Ground pressure of 14 Pa (2 psi) or less is recommended for fragile ecosystems like marshes.[4] Decreasing the ground pressure increases the flotation, allowing easier passage of the body over soft terrain. This is often observed in activities like snowshoeing.
Example: Average ground contact for a Hitachi EX 200 (20 ton)
Calculate average ground contact area (footprint):
A = length x width
A = 132.1″ x 23.6″ =3115.2 x 2 for two tracks = 6230.4
Calculate average ground contact pressure:
P = load / area
P = 43651.5 lbs divided over the area 6230.4″ = 7 lbs per square inch
P = 7 psi or 48.2kpa
For comparison, a 100# woman in high heels applies about 1500 psi!
125 pound person wearing 1/4 inch square spike heels. Rocking back on both heels = 1,000 PSI per heel. Standing on one heel = 2,000 PSI. Hundreds of people walking back and forth in spike heels = one sheepsfoot roller.This from a Kansas Pond Builder and PB Forum Member:
""There are work around's of not using a sheepsfoot roller.
Now take the square inches that comprise the grousers only on the tracks. That is going to be about 1/32 the surface area of the entire track. So 32 times more psi compaction capability (bulldozer type grousers, not excavator). Problem is you have to go over the area 32 times to get it. You can greatly increase the compaction capability of a dozer simply by making multiple trips preferably at varying angles. The other caveat is it only compacts to about 2"-3" deep so the lifts have to be shallower. I like to cris-cross. Is it efficient? no. If you have a large area to do, finding a rubber tired scraper or sheepsfoot would be a much better idea. But it is a work around, particularly on a small job. When they figure the compaction pressure of a sheepsfoot they do not figure the drum area. They figure the feet area. It takes multiple passes even with a sheepsfoot to realize its full compaction capability. By using the grouser area of a track tractor the compaction factor is greatly increased. But it takes many passes to realize it.
Another work around with a dozer on a dam, especially a small rather narrow dam, is to compact it with the dozer while going over center. If you only have the center part of the tracks touching, say half, you have doubled the compaction force. Again it is a work around. Is it efficient? No. But it is another method that an experienced operator can do to "make do".
About the only BOW's I have seen a sheepsfoot used in this area is on government jobs. Rubber tire scrapers are used more often but mostly on larger jobs. I would hazard to say thousands of ponds in my area (of Kansas) have been built with nothing with a dozer and by and large nearly all hold water. I know of one that did not but my "guess" is that the area it is in was undermined (old shallow coal mine shafts). Maybe a sandy area of soil was a factor"
If I put new terraces in a field in Kansas and get a low spot, I have a pond. It holds water till it evaporates.
I know this forum obsesses over sheepsfoot rollers, but not all areas of the country or soil types require their use. Are they a good idea on any project? Sure. And on a significant size project would be very good insurance. But on a pond less than one acre? However a leaky pond is still a constant problem to deal with especially if it could have been easily avoided. I would say they almost are never used in my neck of the woods. I never used one on the three new ponds I have built on my property (did use a rubber tire scraper on the dam and core, but nothing on the bowl). But we have clay pan soils with the subsoil measuring water permeability in very low hundredths of an inch per hour so have excellent material to work with. That is natural, uncompacted subsoil.
So I would not have him filling it back in and starting over just because it was only compacted with a dozer. A good operator on a small project can do quite a bit with a dozer as far as compaction. Sheepsfoot rollers are just not easily rented in all areas. Especially for small jobs. They would be hard to come by here. There are work arounds IF you have especially good material to work with. If you have marginal material........... better do it right.""
Compaction discussion.
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=428419#Post428419Discussion of using a Scraper for pond compaction
The main reason the weighted scraper is not a good compactor is because it does not knit and intertwine the lift layers together. The scraper smashes the layers however the two layers smashed together sheets can eventually have seepage between those layers of lifts because the smashed lifts are not well knitted together as one compacted unit. If scrapers were really good at compacting layers of dirt/clay there would not be specialized equipment of sheepsfoot types of soil compactors. Also the mechanical sheepsfoot compactor squeezes water out of the soil so it less likely will allow seepage through it.
Think about it. Use the best tool for the job if you want the best result with the material you are working with. Where this really becomes very important, is dirt for building almost all pond basins has patches or spots where the clay is not at optimum structure and looser soil exists. In these areas the soil should be mixed together and these spots are where OPTIMUM compaction becomes very important to minimize seepage and leakage in freshly built ponds and t
hen also years later as the seepage can increase between the sheet formed layers as pond ages. I would never use a loaded scraper to build a pond. Way too many chances for leakage spots to occur even with all good clay material. It is much cheaper and quicker to rent the right sheepsfoot than to fix a pond leak. Just finding the seepage area/s can be a BIG challenge. Is it one spot, two spots or several areas where seepage is happening? Fixing just one may not really fix the leak. That is why it is very important to do it right the first time. Cheap way is rarely the best way.
Padfoot rollers: Padfoot — or tamping foot — rollers break the bonds between soil particles to compact them better. The tapered feet prevent the soil from fluffing, decreasing its ability to absorb water. Padfoot rollers have large lugs and could either be static or vibratory. The static models are also known as tamping rollers. The drum is covered with bumps that knead and knit the soil layers together and increases its overall compacting strength. Typically, padfoot rollers are used for clay and other fine-grained soils. They operate at high speeds and can also break large lumps. Padfoots are versatile, typically used to compact cohesive soils like clay and silt. They feature a heavy vibrating steel drum with rectangular or cylindrical pads that pierce and compress the soil, resulting in a compacted surface.
From construction websites. The sheepsfoot roller is most effective for compaction of plastic soils like clay or silt, according to Bomag Americas a leading roller manufacturer. The sheepsfoot compacts from the bottom of each lift towards the top. High contact pressures cause the feet to penetrate through the loose material and actually compact the material directly with the foot tip to reach optimal soil compaction levels. A number of passes are required with a sheepsfoot roller because of the small area compacted by each foot. Self-propelled embankment compactors, are capable of higher productivity than towed sheepsfoot rollers because they can travel at higher speeds. A tamping foot mechanical roller has feet, or pads, that penetrate the soil, compacting from the bottom to the top for uniform density. The forces of gravity and vibratory impact simultaneously compact from the top down. Due to the foot shape, and in combination with vibration, these rollers achieve a kneading and impact effect while the imprints left contribute to a reduction of water content.
Univ of Missouri Advice for Leaky Ponds.
https://extension.missouri.edu/publications/g1555USE OF BENTONITE AND POLYMERS
https://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=529641#Post529641https://forums.pondboss.com/ubbthre...rds=bentonite&Search=true#Post125536
