pile supported retaining walls

huangyhg

pile supported retaining walls
i am looking for a reference for the design of pile supported cantilevered retaining walls.
whats the reason you want it on piles?  just wondering.
soldier piles?
we have done a few of these walls in the past, and have not found a good reference to refer to, so, if someone know of one, we would like to know as well.
that said, a few things on how we have done them that seem to work.
- deisgned the stem as a cantilever beam, with fixxed base, out of the top of the pile cap. used simple concrete beam equations.
- deisgned a continous pile cap along the length of the wall that was able to transmit the moment from the base of the wall (torsion to a cross-ection of the pile cap).
-spaced a set of 2 piles ( on front, one in back) at required spacing along the length of the wall to take the sum of the moments between the sets of piles. the back pile was placed directly beneath the wall stem, as the moment from the stem causes uplift to the back pile, so we tried to keep as much of the weight of the stem over this pile to reduce the tension in the pile. the front pile then takes the compression, so we wanted to keep as much weight off of this pile as possible.
-used the dowel from the pile cap into the stem wall as both the dowel to the stem wall and the pile cap reinforcing by hooking the end with 180 hook.
- have had to batter one or both of the pile to take out the horizontal thrust at the base as did not have anywhere near the pssive soil pressure in front of the pile cap to handle it.
a couple of these walls got pretty big. for an 20' tall wall (40 psf equivalent fluid pressure, i seem to recall) we had a 2'-0" thick stem with #9's at 8" o.c and pairs of piles (100 ton capacity piles) at 4'-0" o.c.
hope it helps a little. good luck with this.
just a suggestion - consider driven sheet piling and get the benefits of piling and a cantilevered retaining wall, all at the same time. if this concept can be used, look on my website (link below) for (old) info on sheet pile design.
"foundation engineering" by peck, hanson & thornburn (second edition) section 26.8 deals with pile supported retaining walls.
i have found the following reference to be extremely useful but concise as well: