GGU-STABILITY: Verification of inner stability

Verification of inner stability can be performed using the original GGU-STABILITY method. However, the generation of slip surfaces remains time-consuming. This process is simplified by additional functions in the "Nail wall" menu, which substantial quickens generation of nails in a regular array.

Following generation of the slip surfaces, the inner stability can be investigated using the menu item "Safety/Utilisation factors/Analyse slip bodies". The slip surfaces can be analysed according to either "Janbu", the "General wedge method" or the "Vertical slice method".

In accordance with current standards, the governing verification for nail design is the one producing the greatest nail forces. The following investigations are necessary for this:

• Load components in the nails arising from slip body investigation for final and construction condition

• Load components in the nails arising from earth pressure on the concrete shell or exterior skin. The earth pressure from the nailed soil prism acting on the concrete shell or exterior skin may be adopted at 0.85 x active earth pressure value, but without applying cohesion. The earth pressure distribution may be adopted in a rectangular configuration, including in stratified ground. The wall friction angle is adopted at = 0.