Volume 6 – Geotechnical Manual, Site Investigation and Engineering ...

Chapter 7 RETAINING WALL
b) Fixed-end Method
A wall designed using Fixed-end principles is embedded sufficiently deep enough so that at the foot
of the wall, both translation and rotation are prevented and fixity is assumed. This is the condition
assumed in the design of a cantilever sheet pile wall. Figure 7.22 (a) and (b) illustrated the
deflected shape of a cantilever sheet pile together with the conventional and simplified pressure
distributions used for design. An example on the application of this method in Cantilever sheet pile
wall desiGn is given in Item 7.6.3.3 below.
Dredge Line
Deflected shape
of pile
(a)
Figure 7.22 Lateral pressures distribution for Fixed-end Method of design of cantilever
sheet pile wall in granular soils: (a) Idealized distribution (b) Simplified distribution
(b)
A tie or prop may also be provided at the upper part of the wall as shown in Figure 7.23 (a), (b) and
(c). The effect of toe fixity is to create a fixed end moment in the wall, reducing the maximum
bending moment for a given set of conditions but at the expense of increased pile length. The design
method used (whether Free-end or Fixed-end Method) should also consider the effects of hydrostatic
pressures and surcharge loads, which are usually added to that due to the soils.
Deflected shape
of pile
(a) (b) (c)
Figure 7.23 Fixed-end Methpod of Design of Prop Sheet Pile Wall in ranular soils (a) Deflected shape
of wall (b) Idealized lateral preswsure distribution (c) Simplified Lateral Pressure Distribution
March 2009 7-29