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  1. #1
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    extreme bench cut

    The question is what is the maximum practical sidehill grade that a full bench cut can be done?

    The site we are working on is an old pit that the trail currently runs fall line down into the pit and then up, with the banks caving away. We have had the IMBA TTC take a look at the site and they suggested a bench cut around the sides of the pit. Makes sense to me, but in a couple of locations the side slope is extreme. If I'm thinking correctly about how to express grades, well in excess of 100% or 45deg. It seems like the backslope might require a ton of excavation and be prone to instability. In a couple of the worst spots, I'm thinking of some sort of wood structure rather than do all he excavation. Soils are a gravel that does not compact all that well.

    Any experience out there with this sort of situation?

    Thanks,

    DS

  2. #2
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    Hey DS,

    I was thinking the same thing at this spot. Build a bridge and tip it at a 45 deg angle.

    Isn't there a ladder ramp up in the Massabesiac area that kind of resembles the problem you are talking about

  3. #3
    mtbr member
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    crib it?

    Crib wall back slope -- rock, railroad ties, whatever...

  4. #4
    Builder of Trails
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    I built a few legs of trail and some turns on 110% slope in the King Range on the Lost Coast of CA. I used a Takeuchi TB016 mini excavator to do it, though,and didn't cut much of a back slope. I mostly scraped away the loose stuff to keep it from falling onto the tread after construction.

    It can be done; it just takes a lot of effort.

    D

  5. #5
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    Tacrac - I think the plan is to move away from the existing route and create something more sustainable. There is no really effective way to harden the existing trail long term.

    We will definitely be doing this by hand, so yes it's going to be a lot of work. On a 100% or steeper sideslope, it sounds like we may have to work the backslope 6 or more feet above the trail to avoid an almost vertical backslope.

    I do wonder if there is a any reason not to consider a boardwalk in some areas. I've seen it done but it's not common.

    Thanks for the input.

    DS

  6. #6
    featherweight clydesdale
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    Quote Originally Posted by ramshackle
    On a 100% or steeper sideslope, it sounds like we may have to work the backslope 6 or more feet above the trail to avoid an almost vertical backslope.

    DS
    I've had a few beers so some feel free to correct the math. On a 100% slope (1 foot of rise/1 foot of run) a typical 3' tread width would require a 3' deep cut on the uphill side. Blending the backslope, you could be going up 6 feet. Can you do a 2' wide tread?

    +1 vote for the mini-x. Talk to the land manager and scrape together $200 for a day.

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