Soil arching action
Soil arching action
(OP)
Is there some particular depth of a soil where there is no increase in vertical load at that depth due to the weight of the soil? In other words, is soil able to bridge itself or is there arching action at some given depth? As an extreme example, say I am interested in the soil pressure 300' below ground. If someone were to place an additional 2' of soil at the ground surface, it seems like the load due to the additional 2' of soil would not be "felt" at a depth of 300'.





RE: Soil arching action
RE: Soil arching action
RE: Soil arching action
RE: Soil arching action
If the loaded area was just a few feet by a few feet, you could calculate some stress response at 300 ft, but it'd be trivial. Typically, if the change in stress is less than 10 percent of the overburden stress, we'd ignore further integration.
f-d
ípapß gordo ainÆt no madre flaca!
RE: Soil arching action
Yes, a point load, or a load over a small area, will distribute so that it has negligible effect through deep fill.
But no, you can't rely on arching to transfer uniform load away from a structure, unless it is very flexible. A typical reinforced concrete culvert or arch structure will be stiffer than the surrounding soil, so it will attract load rather than shed it. If the depth of fill is increased then the design vertical load should be increased in proportion.
Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/
RE: Soil arching action
This is an elastic problem.
It all depends on the width of what you plan to place on top.
Usually, after a depth of 2 to 3 times the width of the base, the soils underneath will not feel anything you place on the ground surface.