GGU-RETAIN: Bedding conditions of wall toe

Classical methods of computation recognise two limit states for bedding of the wall toe:

• Limit state 1:
  Wall toe freely embedded on resultant of passive earth pressure.
  Embedment depth is determined through iterative displacement of a horizontal support. Embedment depth is found when support force is zero.

• Limit state 2:
  Wall toe fully fixed.
  Determination of the embedment depth is achieved through iterative displacement of a fixation point at the bottom of the system. The embedded depth is found when the moment is zero at the point of fixation.

For full fixation in accordance with the EAB, GGU-RETAIN increases the theoretical embedment depth by 20%. Between the two limit states, intermediate conditions of partial fixation between 0 % and 100 % are possible. If you want to compute partial fixations, GGU-RETAIN will first calculate embedment depths for the two limit states. The necessary embedment depth is then obtained through linear interpolation between the two extremes. In the same way, for a given section length, the degree of fixation is determined from the two extreme embedment depths. The necessary longitudinal extension (length addition) of between 0 % (for free earth support) and 20% (for complete fixation) is also determined by linear interpolation in compliance with the EAB.

Thus, there are two different ways in which section length and the degree of fixation can be determined:

• determination of section length for a given degree of fixation of wall toe,

• determination of degree of fixation of wall toe for a given section length.