lateral soil pressure
lateral soil pressure
(OP)
How do you determine the lateral soil pressure on a proposed caisson shoring wall, that is caused by the existing building spread footings? There are formulae given in the Canadian Foundation Engineering Manual and other soil mechanics texts for the effect of a "point" load and for a "line" load, but not for a spread footing load.
For example, there is a row of 2 m square spread footings at about 9 m centres, the bottom of the footing being near the top of the proposed excavation, and the row of spread footings being located about 2 m away from the proposed caisson wall.
For example, there is a row of 2 m square spread footings at about 9 m centres, the bottom of the footing being near the top of the proposed excavation, and the row of spread footings being located about 2 m away from the proposed caisson wall.






RE: lateral soil pressure
I have not presently the particular case in Mathcad but have the formula in cartesian I think; it is just a matter of building the integration for the loaded areas and the points of interest.
See attachment. If you are ready to substitute the loading for just the resultant in planes orthogonal to your wall and the footings are reasonably away then just the use of the worksheet may identify the local maximums since the effects of far away footings quite likely can be dismissed to this purpose.
All above as if a cut in the elastic halfspace would represent the status in the wall. Other "hybrid" view is just to get the vertical stress (or maybe better the "total" vertical stress, that compounds the vertically shearing forces) and multiply by a K factor.
Other way to readily get the status in the elastic half-space is to make a solid model with a cube of the elastic half-space in FEM and subject it to the footing loads, then inspect the stresses at the vertical plane of your wall.
RE: lateral soil pressure
RE: lateral soil pressure
RE: lateral soil pressure
Equate your footings to rectangular areas of plastified soil stress response, placed in plan. Then use the chart to obtain the vertical stress, and then a K factor.
RE: lateral soil pressure
RE: lateral soil pressure
Reference is
Earth Pressures and Earth Retaining Structures, 2nd ed.
Clayton, Milititsky and Woods
Blackie Academic and Professional - Chapman and Hall Imprint 1993
RE: lateral soil pressure
RE: lateral soil pressure
FWIW I would typically use the same as Lion suggests.
EIT
RE: lateral soil pressure
"We have used as reference
Elasticidad, 4th ed.
Eduardo Torroja
Dossat, Madrid, 1967, page- 245"
See atachment.
Eduardo Torroja was a well known civil engineer ("Ingeniero de Caminos, Canales y Puertos" of fame even in the XX century thirties' for his works in shells and other written engineering works. Today the main Institute in Spain related with concrete bears his name.
So if someone finds something in error, quite likely it would be mine or some errata.
RE: lateral soil pressure
RE: lateral soil pressure
RE: lateral soil pressure
RE: lateral soil pressure
RE: lateral soil pressure
From
CIRIA C580
Embedded Retaining Walls - guidance for economic design
London 2003
RE: lateral soil pressure
RE: lateral soil pressure
AASHTO
USACE/NAVFAC
FHWA on walls
Geotechnical Circular
and of course some of the many general texts ... one never ends finding resources in one protracted search; I have not yet searched those above.
Attached, just the case for strip load in the CIRIA C580 publication.
RE: lateral soil pressure