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

Chapter 7 RETAINING WALL
d) Diaphragm Wall
Diaphragm wall construction is very similar to bored pile wall. This wall system comes in panels and
the soil removal is using a mechanical grab. Water stopping
system is introduced between the wall
panels to
ensure total
water tightness.
Diaphragm wall system is not suitable for area with shallow bed rock. Rock chiseling during the
installation may affect the construction duration and causing vibration disturbance to the
surrounding.
7.6.3
7.6.3.1
Sheet Pile Wall
Types of Sheet Pile
Wall
The sheet pile wall system can be
further divided into the
followings categories according to the
form of support provided, namely:-
a) Cantilevered or unbraced wall
b) Supported wall either with anchor/tie-back or bracing/struts
The various types of sheet pile wall are as illustrated in Figure 7.21
Figure 7.21 Type of Sheet Pile Walls
a) Cantilever Sheet Pile Wall
A cantilever sheet pile wall is one that does
not have any additional support such as bracing,
anchors, or other structural elements and thus relies on its flexural strength and embedment to resist
the lateral earth pressures. The imposed lateral earth pressures on these walls create large flexural
stresses in the steel and as such,
these types of wall generally are not
more than 3 to 4 m high.
Cantilever walls also experience greater lateral deflections and are more susceptible to
failure due to
scour or erosion of the
supporting soils.
b) Supported Sheet Pile Wall
Most sheet pile walls
include additional lateral supports, using internally bracing/struts or tieback
anchors (known as braced walls or anchored walls respectively). The additional support provided
reduces the flexural stresses and lateral movements in the wall, thus permits construction of walls
much taller than that of cantilever
design. In this situation the soil conditions at the toe of the wall
are not as critical to the overall stability of the structure and depth of embedment required would not
be as deep as in the case of a cantilever wall.
March 2009
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