FLOOD03439

• County: Statewide
• Basin: Statewide
• Title: Design of Sheet Pile Walls
• Date: 3/31/1994
• Prepared By: US Army Corps of Engineers
• Floodplain - Doc Type: Educational/Technical/Reference Information

.

.

.

.

c. W~dg~ _thods for so/I pr~sslU~s. 1be coeffi-
cienl method does nol accounl for !he effeclS of sloping
ground surface:. sloping soil layer boundaries, or the
presence of wa1Vsoil adhesion. When any these effeclS
are prescnl, the soil pressures are calculated by a
numerical procedure. a wedge melhod. based on the
fundamenlal assumptions of !he Coulomb theory.
Praclical evaluation of soil pressures by the wedge
mclhod requires a compUler program. (CW ALSHf
User's Guide (USAEWES 1990) or CWALSSl User's
Guide (Dawkins 1992.)

4-4. Surcharge loads

Loads duc to sIockpiled material. machinery. roadways,
and OIhcr influences resting on the soil surface in the
vicinily of the wall increase the 1aIcra1 pressures on the
wall. When a wedge mclhod is used for calcuIaling the
earth pressures, the resullanl of the surcharge acting on
the lop surface of the Cailure wedge is included in the
equilibrium of the wedge. If the soil syslcm admilS 10
application of !he cocrrtcienl melhod. the cffeclS of
surcharges. OIher than a uniform surcharge. are
evaluated from the theory of clasticily solutions
presenled in the following paragraphs.

a. Uniform S1U"charg~. A uniform surcharge is
assumed 10 be applied aI all poinlS on the soil surface:.
The cffecl of !he uniform surcharge is to increase the
effective vertical soil pressure, p. in Equations 4-' and
4-8, by an amounl equal to the magnilude of the
surcharge.

b. Strips loads, A Slrip load is continuous para1Jel
to the Iongiludina1 axis of the wall bul is of fmile exlenl
pclpCndicular 10 !he wall as ilIustta1ed in Figure 4-S,
The additional pressure on the wall is given by the
equations in Figure 4-S. Any negative pressures caI-
culaled for SIrips loads are to be ignored.

c. Un~ loads, A continuous load parallel 10 the
wall but of narrow dimension perpendicular 10 !he wall
may be IreaIed as a line load as shown in Figure 4-6.
The lalera1 pressure on !he wall is given by the equation
in Figure 4-6,

d. Ramp load. A ramp load. Figure 4-', increases
linearly from zero 10 a maximum which subscqucttlly
remains uniform away from the wall. The ramp load is
assumed 10 be continuous para1JeI 10 the wall, The
equation for IaIera1 pressure is given by the equation in
Figure 4-4.

EM 1111).2.2504
31 Mar 94

Figure 4-5. Strip load

mH

::t:
c:

::t:

Figure 4-6. Line load

I" x _" c .1

N

OH

~/2
oH= : {~-SIN~ COS2 a}

P

m>0.4

4P { m2n }
lll= ltH (m2+n2)2
m~0.4
P { 0.203n }
'\-t = H (0.16+n2)2

~

~ { R2}
oH=.!L c~+xa+2z In-
ltC R1

Figure 4-7. Ramp load

4-5