Agree with responses above. In particular, bearing capacity for a larger diameter shaft increases the B*gamma/2 term proportionally (but not the depth or cohesion terms), so the bearing capacity of a large diameter shaft in sands would be higher. On the other hand, if they consider settlement...
There are two "real" theoretical solutions, I don't know which is correct, to the original thread.
Its either
1) Having evaluated wedge equilibrium personally, the active pressure for a wedge is proportional to its mass. So if you know it has a regular shape of a right triangle of 45 + phi/2...
There's this great site about 20 miles south of Syracuse New York where artesian pressures pushed up through an (improperly?) sealed borehole at a small bridge abutment. The water came up and the sand layer also, not only wiped out the bridge abutment, also cause an acre or more of sand boils...
It sounds like you should plan on adequate drainage to lower the water level to at least the bedrock surface, and have drain rock all the way down. If you don't do an open excavation with room for back formwork near the rock, which would allow for a big gravel drain, how do you propose to build...
Just to point out that there is not much of a cage, only the diameter that can fit through the center of the augers. As noted above, often this consists of a single bar at greater depth. I would generally not trust these things for any significant lateral pile capacity (since I am in a high...
The seismic active pressure is generally computed using some method (Mononobe-Okabe eqn for example) then divided back into static and seismic components. The static pressure is still applied as conventional (triangular for a non-braced wall, rectangular for braced wall). The additional...
Can't make much of a recommendation without knowing the height and construction method of the wall. Concrete cantilever footing?
Also, is there existing soil on the upslope side of the wall (so there will be little new surcharge. e.g. are you replacing an existing 2H:1V slope with a wall), will...
Assuming this is not high pressure gas, and is a new, flexible pipe, I don't suppose that putting a temporary footing would be a problem. Consider voiding under the footing (styrofoam, void forms) so that the stress is distributed less to the soil overlying the pipe. You really haven't said...
Geotechnical monitoring -
I would think the loads and soil are probably about the same now versus 30 years ago (e.g. it hasn't fallen down for 30 years), its the wood pile capacity you want to evaluate/test. Or are they planning to enlarge the tower loads and need to know if it has the...
Structural protection - I was thinking something more like a blow-out collector, e.g. a big bell-shaped thing ( a 15 x 15 concrete slab, on integral legs, about 5 feet high, that can be dropped by a crane over the track, the third rail, no trains can go through, but the third rail stays on...
Helical piers installation also goes up to 6" pipe sections or larger (with a helix on the bottom of course to increase the bearing). Talk the Chance about that. I think they can get up to 200 to 300 kips. In Nevada, they can go into fairly stony ground.
Advantages are there is no pile...
It seems like you should design the wall for level ground, excavate to that ground level, then put in a stiff waler on the wall and diagonal braces from the waler as you dig the utility trench to temporarily take up the active load on the cantilever wall. The braces would be to a temporary...
According to AASHTO 17th Edition Kh is 1/2 of the peak ground acceleration, unless you are designing an anchored wall (not your design) which required 1-1/2 times peak ground acceleration. If you are in a high seismic area it should not be limited to 0.2 g. However, you can also use the...
You don't have potential for excessive settlement for a 5-story building on loose silts and sands, so you would need a mat/deep foundation/ground improvement anyways?
Penetration methods (SPT and CPT) generally are piss-poor at liquefaction prediction in borderline silty sands and silts, but...
If you can excavate at the top of the wall a foot or two, install a geogrid or strength geotextile layer anchored to the back of the PT timber. With a 5' wall, it should nearly be possible to design a single-layer MSE wall, the tail may just have to be a little long, or have an anchor trench...
Some but not all cohesion is caused by negative pore pressures in the soil, therefore over time as the pore pressures due to initial construction dissipate, the strength will drop back to low cohesion and an effective stress friction angle will control again. If you designed for significant...
Much of this discussion reports on the somewhat over-rated differences between geogrid and geotextile. While there are some geotextiles that are only for separation or filtration (light ones or non-woven fabrics with considerable elongation), my experience has been that there is a geotextile...
The drystack site is providing more traditional wall construction, perhaps why they do not advocate drain materials. Clearly most drystack walls that survive to the current day have had adequate drainage (and the ones that did not fell down long ago).
In Nevada, there is considerable use of...
Most geotechnical papers on rockfill are for earth dams which are poorly-compacted, therefore may not be much use. South of Reno, a contractor constructed a 150-foot high fill across a canyon, including 3/4H:1V MSE slope reinforcement, to support falsework for the Galena Creek arch bridge...
