Wall Data Tab

The Wall Data tab is where the main retaining wall geometry is defined. This page controls the shape of the wall, the base layout, the surrounding soil levels, and several key features that directly affect stability and pressure calculations.

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Note:- it is assumed the wall is being designed for a 1 metre length into the screen, therefore the forces, etc are entered in kN/m or kN/m2.

Wall Geometry

Use the left section of the tab to define the primary wall dimensions, including:

Wall height
Upstand above soil level
Toe length
Heel length
Wall thickness

All dimensions are entered in mm.

You can also define the slope of the soil surface behind the wall in degrees. This value should be less than the internal angle of friction of the retained soil.

Sloping wall stem

A sloping wall stem can be created by entering a horizontal offset between the top and bottom of the wall stem faces. This allows you to model tapered or battered wall shapes, as shown in the sloped wall example later on this page.

Wall movement controls

The wall sketch includes arrow controls to make geometry adjustments quickly:

Up and down arrows at the top of the wall move the upstand in 100 mm increments
Left and right arrows in the middle of the wall slide the stem horizontally along the base

Sliding the stem does not change the overall base length. It changes the distribution of the base into toe and heel, which in turn changes the amount of overburden acting on the heel. This can have a significant effect on sliding and overturning stability.

Front Soil and Base Data

The second sketch on the tab is used to define the soil and base conditions in front of the wall.

Here you can enter:

Height of the lower soil in front of the wall, measured above the top of the base
Slope of the front soil surface
Base thickness

Unplanned excavation depth

You may also specify an unplanned excavation depth. This value is used in the passive pressure calculation.

If left as zero, the program automatically adopts:

10% of wall height, with
a maximum of 500 mm

This default reflects a common design assumption and ensures the passive resistance is not overestimated.

Point of Overturning

The red dot shown in the sketch represents the point of overturning. This point is defined as a percentage of the base length and is usually taken at the front edge of the base. Adjusting this value allows you to match the overturning check to your chosen design assumption.

Nib Geometry and Sliding Resistance

A nib is introduced on the bottom of the base to resist horizontal sliding. Where a nib is used, enter:

Distance from the front of the base to the nib
Nib width
Nib depth

The nib increases passive resistance and can make a significant contribution to sliding stability.

Active pressure on the nib

Depending on the nib position, you may choose whether the active pressure on the back of the nib is included in the design. Typical design practice is:

Nib at the heel: active pressure on the nib is usually included
Nib at the front of the toe: active pressure on the nib is usually ignored

This option allows the model to reflect how the nib is expected to behave in practice.

Water Table Level

The height of the water table above the top of the base can be set. If there is no water table to be considered you can enter a negative value to bring the water level down below the bottom of the base.

Base Level Adjustment

The sketch also includes up and down arrows at the base.

These controls move the base relative to the wall stem, which lets you quickly adjust:

wall height above the base
front soil height

This is especially useful when testing alternative arrangements during early design checks.

Reinforced Concrete Wall Output Graphics

The data entered in this tab is reflected in the reinforced concrete retaining wall graphics shown below. which also show the active pressure and bending moment diagrams, bearing pressure and passive pressure diagrams.

These diagrams provide a quick visual check of how the geometry and loading assumptions affect the wall behaviour.

Stepped Wall Option

If you are designing a stepped wall, such as a masonry wall that becomes thicker toward the base, tick the Stepped Wall option. This is commonly used where the lower part of the wall must resist higher bending moments than the upper part.

Entering step dimensions

Step geometry is entered using inner and outer step definitions. Each step entry should be written as two values separated by a semi colon:

Vertical distance from the top of the wall to the step position
Horizontal step out distance

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Inner face = face in contact with retained soil
Outer face = face away from retained soil

This distinction is important when defining stepped masonry walls, since the wall capacity and bending resistance depend on the correct wall profile.

The stepped wall data in the tab is shown in the stepped masonry retaining wall graphics below.also show the active pressure and bending moment diagrams, bearing pressure and passive pressure diagrams.

A red line is shown to the right of the bending moment diagram. This indicates the masonry wall capacity as the wall steps outward, making it easier to compare demand against available resistance along the wall height.

Sloped Wall

To create a wall which slopes as shown below, enter a positive value for the front and a negative value for the back.

a nib below the base
an upstand above soil level

To create a wall with this shape:

enter a positive value for the front face
enter a negative value for the back face

This produces the tapered wall stem shown in the example graphic.