## How does WALLAP calculate the new displacement with the changes of wall stiffness?

## How does WALLAP calculate the new displacement with the changes of wall stiffness?

(OP)

Hi, I just have one question to ask regarding the use of WALLAP for a deep excavation problem. WALLAP allows the users to reduce the wall stiffness in order to model the long-term stiffness of the wall at the end of the excavation. I am just curious to know how WALLAP carries out the analysis with the new wall stiffness. Since all forces are in equilibrium following the previous stage analysis - out-of-balance force is zero, I would expect that just changing the wall stiffness would not lead to any more displacements in the solutions. But WALLAP does gives large additional displacement based on the updated wall stiffness. I searched through WALLAP's manual but it doesn't say how this is done within the program. I suspect the program just recalculate the whole thing again from the beginning with the new stiffness but would like to know whether there are other reasons for that.

Thanks a lot!

Thanks a lot!

## RE: How does WALLAP calculate the new displacement with the changes of wall stiffness?

## RE: How does WALLAP calculate the new displacement with the changes of wall stiffness?

Thanks for your reply. I would appreciate if you could explain a bit more on this "Initial stress" technique to compensate for the incompatibility. Does this approach re-evaluate the initial stresses at both sides of the wall based on the specific excavation level (at the stage where wall stiffness is reduced)and then solve the equilibrium equation again to get the results? I just try to figure out how this is done within the program.

## RE: How does WALLAP calculate the new displacement with the changes of wall stiffness?