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Exercise 26 Wall Anchoring 107
Exercise 26
Wall Anchoring
OBJECTIVE
The objective of this exercise is to execute anchoring
for landscape retaining walls using verticals (vertical
timbers), deadmen, and geogrid.
Follow manufacturer’s instructions when using
TEXTBOOK REFERENCE
Information related to this activity can be found in the
INTRODUCTION
Landscape retaining walls need to be anchored to improve
stability and counter the forces of gravity and soil/water
Vertical timbers are buried wood members placed
in an upright position directly in front of the joints of
stacked timber walls. Deadmen are horizontal timbers
placed behind staggered-joint timber walls. Deadmen are
anchored into the hillside to provide resistance to forces
pushing the wall forward. Geogrid is a fabric-like land-
scape material that is hooked or sandwiched between
Batter
To construct a wall with step-back (or stair-step) batter,
• Place the first course level.
• On each subsequent course slide the wall material
back from the front of the previous course. A
typical dimension for this setback would be
1 inch, but it may vary based on manufacturer
recommendations. Many segmental units have
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108 Exercise 26 Wall Anchoring
Vertical Timbers
To install vertical timber anchoring use the following
steps:
• Following completion of the second or third
course, auger 1 foot diameter holes in the ground
in front of the wall and centered on the joints
between timbers (Figure 26–2). The recommended
Deadmen
Deadmen should be installed every fourth vertical course
of a tie/timber wall. Measuring horizontally from the end
of the wall, install a deadman every 8 feet.
To construct deadman anchoring use the following
steps:
• Cut an opening in the appropriate course of the
A. First course is aligned
with planned wall location
Step–Back or Stair-Step Batter
Step
back
B. Subsequent courses are
placed back from front edge
of previous course
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Exercise 26 Wall Anchoring 109
• When placing the next wall course, connect it to
the deadman with a 12 inch nail.
• Backfill and compact over the deadmen when the
wall is complete.
Geogrid
Manufacturers or design professionals must calculate if
a wall requires anchoring with geogrid fabric. These cal-
culations should indicate the course in which the geogrid
• After compacting the backfill for the course
below the geogrid, roll the geogrid out flat behind
the wall along the entire length of the area to
be reinforced. The backfill area may have to
be widened to accommodate the width of the
geogrid.
Stacked
wall
Deadman spacing
8
Deadman extends
through to face of wall
Wall
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110 Exercise 26 Wall Anchoring
Lipped units may be set in place with the geogrid installed
between courses.
PREREQUISITE EXERCISES
Students should have successfully completed Exercise 5,
MATERIALS REQUIRED
• Proper clothing and safety gear
• Power auger (12 inch diameter) (prepared for
operation)
• Extended 3/8 inch auger bit
• 50 foot heavy-duty extension cord and access to a
• Square-nosed shovel
• Whisk broom
• Supply of wall materials, including ties/timbers
and segmental retaining wall units (including
EXERCISE DESCRIPTION
To complete this exercise, install the anchoring method
appropriate for each segment of wall. This exercise can be
combined with Exercises 22, 23, 24, and/or 25.
Figure 26–4 Geogrid placement.
Free-draining
angular fill
over wall pins
Wall material
Compacted
backfill
Compacted
backfill
© Delmar/Cengage Learning.
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