Marcel, it’s damn near impossible to get good compaction on that steep of slope without benching in the material and compacting with a tamping rolling with optimum soil moisture content. Back in the 80’s when I had inspectors working for me it would require my inspectors to camp out on the fill. If they left to take a piss some contractors would try to hog in 2-foot lifts. It reminded me of the Wyle E Coyote and the Sheep dog let your guard down and the contractor tried to bury tree stumps in the fill.
On that steep of a hill I would recommend push piers or helical piers installed below the fill material or down to rock. The fill will settle, but the piers will stay in place. The only problem you my get some hillside creep over time that could push the piers down hill along with the house foundation.
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Cool. Thanks. The whole home was on the hill, no grading away from the home. Major water in the garage that was built right on the ground with wood. Not good for sure.
Yes, supervised it for years. But, residential is a different story when it comes to a non-existing compaction. I agree on that point. Then they add water and wonder what happened.
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Slope Creep is a possibility…This is when structures like fences decks etc. are built too close to the edge of a hillside and the dirt underneath gives way as it naturally would causing settlement, erosion etc. Sometimes you’ll see fence posts on a hillside with the posts leaning outward is a sign this is happening.
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Slope or Hillside Creep is something that I only began to appreciate in the last ten years. Apparently, I am not alone, because I see problems with it in houses only a few years old, even though I don’t do that many houses on steep slopes. A buddy sent me a photo of an expensive house that the contractor thought would be clever to put one of the columns for the deck on a car-size boulder ten feet below the deck. Ten years later, that boulder had slid down the hill a foot and took the deck with it. Weirdly, the owner had just lived with it.
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Dana Hall, PE
Looking at the pictures there appears to be structural elements that are out of square, period. The pier in question is probably part of the problem but probably not all of the problems associated with this structure and foundation. The only way that I could evaluate this would be to determine (first) that the structural framing can adequately transfer the vertical and horizontal loads. That would provide a pretty good basis to (secondly) evaluate the foundation support requirements and the best way to accomplish it with the geology we’re working with… That’s just me,…
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