Preparing steep slopes for turf reinforcement mat, scraper / packer

[morrisgruen]

Can anyone advise based on past experience best method / equipment for scraping down and smoothing a badlands type crevice laden sandstone, steep slope (up to 5:1) to accept an Enkamat / hydromulch type erosion mitigation system? Face of slope is up to 30' in height with limited access from the top of slope. The bottom of the slope may be inaccessible for any heavy equipment due to rail operations. Appreciate the reply.
Thanks!

 

[oldestguy]

You are up against a tough situation. If there is any seasonal heavy rain, you may find the installation will fail. My suggestion is that you contact he maintenance sections of state highway departments that may have similar topography. When I was with Wisconsin DOT we tried many ways and few turned out to be permanent. There may be patented methods that they have found to work these days. One thing that has appeared to help is getting the slope prepared is the knocking off of overhanging earth, brush, etc. at top of slope. before doing the slope work.

 

[morrisgruen]

Oldestguy, thanks for the feedback. I'm confident in the Enkamat 7020 and R45 system, it's like a scouring sponge, so the hydromulch / growing medium goes in thick and won't get washed out. The challenge appears to be scraping down the slope so the mat is flush with the slope grade to support best possible cohesion of the sprouting grass and shrub mix. I'm still looking for information on heavy equipment / techniques to get the slope as smooth as possible to accept the mat.

 

[BigH]

But at your very ste (1H:1V) slopes will your mat be stable? How are tying your mat to the rock so it doesn't slide?

 

[morrisgruen]

The Enkamat is folded and buried into a 1'x 1' deep/wide trench about 18" back from the apex of the slope, and then rolled down.
8" min. U shaped soil nails are inserted / triangulated through the mat at 3' o.c. to keep the mat adhered to the slope grade so plant material roots into the sandy surface. This system has successfully been used on slopes up to 70 deg.

 

[oldestguy]

Have you considered a drag line? Interesting that I mentioned this to a getechnical engineer sometime ago and he didn't know what I was talking about. It's an old excavating method, generally using a crane.

These are common (used to be anyhow) for mining gravel under water in stream beds. A derrick or similar is mounted at one end of the site and a cable is run through a pulley there. The operations are then run from the other end via a crane rig that moves about to move the path of the dragline bucket across the area. Distances up to 100 yards have been used for these mines. The bucket drags from the derrick toward the crane.

If you look at the TV program of Lumbering (History channel) their method of hauling up logs is similar. A moveable end anchor could be arranged if one thinks about it (maybe a crawler-dozer with side mounted mast).

Instead of a dragged bucket, perhaps a blade mounted on wheels (as from a tractor) may be OK for grading.

My cogitating.

 

[oldestguy]

Og again:

Interesting subject. If one goes this route, a suitable tool for he "bucket" would be a drag made of structural shapes, such as angles or H sections. These drags are frequently used for grading gravel roads, hauled along behind a truck or tractor. Sections are mounted to steer the gravel back and forth. Even a section of chain link fence with some weights on it works pretty good on loosened material.

 

[BUGGAR]

I saw a couple of large Cats grading a road washout along a flowing river in Alaska. They were cabled together side by side, one working the 1:1 slope along the river while the other paralleled him just over the top of the slope, keeping him just barely out of the river.
You can only do this in Alaska, though.

 

[morrisgruen]

OG and all: much obliged for your suggestions. The concept to drag different shaped forms/tools across the slope surface sounds promising. Because we are limited on space at the top of the slope, perhaps a tripod and winch system on steroids can make this work. We have limitations how far back we can cut the slope, even if we wanted to, so the deeper crevices may need to get filled with a cementitious grout / sand mix, like a slope spackle, to smooth out where we couldn't scrape down far enough. Any other suggestions are welcome, thanks!

 

[oldestguy]

On this subject, how about checking with those that use the dragline method now, as for gold mining, etc.

This site has a video clip of one operation. They may advise details and equipment to think about.

http://www.skylineexcavating.us/gravel-dredging-excavation.php

The system used for US football game video from over the field is another idea for covering a large area, but not of sufficient power.