Sheet Pile
Sheet Pile
Sheet Pile
Depending on the way the retaining structure is built and analyzed, it can be divided
into three categories:
1. Cantilever Sheet Pile
2. Anchored Sheet Pile
3. Braced Sheet Pile
A few key points that define the lateral earth pressure in Figure 8.7:
1. Point A to Point D (p1): Active earth pressure on the right hand side.
2. Point D to Point H (p3): (Passive earth pressure on the left hand side) - (Active
earth pressure on the right hand side).
3. Point G (p4): (Passive earth pressure on the right hand side) - (Active earth
pressure on the left hand side).
4. Point E (L3): Can be determined from equation derived in 2.
5. Point F (L5): To be determined.
Unknowns: D and L5
Equations: F x 0
M B 0
A few key points that define the lateral earth pressure in Figure 8.7:
1. Point A to Point D (p1): Active earth pressure on the right hand side.
2. Point F to Point I (p6): (Passive earth pressure on the left hand side) - (Active earth
pressure on the right hand side).
3. Point G (p7) : (Passive earth pressure on the right hand side) - (Active earth
pressure on the left hand side).
4. Point E (L3): Can be determined from equation derived in 2.
5. Point G (L4): To be determined
Unknowns: D and L4
Equations: F x 0
M B 0
Unknowns: D and T
Equations: F x 0
M o 0
In Sand:
Pu dl ' v K tan
K = K0 if the concrete grout is placed under pressure
Lower limit of K is Rankine Ka
In Clay:
Pu dlca
2
ca = adhesion cu
3
Factor of Safety = 1.5-2.0 may be used over ultimate resistance to obtain the
allowable resistance offered by each tieback.
Braced Cut
To avoid considerable settlement or bearing capacity failure of nearby structure.
To prevent water seepage into excavation
0.3 H
Case (a)
1 1
C av s K s H s tan s H c n' C u
2
H 2
Case (b)
1
C av C1 H 1 C 2 H 2
H
1
av 1 H 1 2 H 2
H
Braced Cut Design
Strut
The strut force can be determined from (b) above.
Sheet Pile
Maximum moment on sheet pile can be determined from (b) above.
Wales
Treated as continuous horizontal members if they are spliced properly.
Or conservatively treated as though they are pinned at the struts.
( A)( s 2 )
At level A M max
8
( B1 B2 )( s 2 )
At level B M max
8
(C1 C 2 )( s 2 )
At level C M max
8
( D)( s 2 )
At level D M max
8
Stability of Open Cut
Terzaghi (1943)
5.7C u B1
FS 1 .2
HB1 C u H
Chang (2000)
0.2 B" C u H
5.14C u 1
L B'
FS 1.5
H q
B = T if T B/ 2 ; B = B/ 2 if T > B/ 2 ;
B = 2 B
Piping of a Cut in Sand
icr
FS 1.5
imax(exit )
sat H 1
FS 1 .2
w ( H 1 H w )
H1 Impervious
Uf = H1+Hw
Depth of Penetration
Pp l p
FS 1.5
Pa l a M s lp la
Pp Pa
Global Stability of Anchored Sheet Pile
Mr
FS 1 .5
Mo