Question for Wallap Users

[handex]

Hey guys,
We have recently purchased wallap and have a question for the regular users.

We have a sheet piled wall retaining 3.2m of loose sand. First stage is to excavate to 1.4m and install walers at 1.2m depth. 3m wide battered slots are then excavated to the full 3.2m at 7m centres and angled props (bearing on the ground) are installed at these locations. Then the intermediate slots are excavated and the props installed in these.

My question is how you usually take this construction sequence into account? We are more interested in the compounding deflections over all these stages, including settlement of the props and the deflection from the slot excavations when the props are not yet installed.

Any advice is appreciated.
Cheers

 

[ItsOnlyDirt]

Hi Handex

I am sure there a fudge factors for doing this sort of thing however WALLAP is a 2D package and what you are trying to do is model 3D effects. If I'm honest I dont likle WALLAP its clunky and outdated though I do admit its useful for some simple walls.

Why dont you try emailing Daniel and see what he recommends?? He's usually pretty swift in getting back to you and it will then also be from the horses mouth, so to speak.

Email is in the help/contact menu.

Good luck

 

[FixedEarth]

It may be faster to do hand calculations in this case.

Draw a 1.4 m excavation height retaining loose Sand then calculate your maximum bending moment and max. deflection. Then do a 3.2 m excavation with a support at 1.2 m and again check for bending moment, deflection and this time tieback force. If both Section modulus values are less than the sheetpile section modulus, you are ok with structural requirements.

Geotechnical perspective-- 1)see if the maximum deflection is within soils report requirements and look out for surcharges.
2) determine you critical gradient and look out for minimal effective stress issues during excavation into loose Sand, particularly if water table is near the surface.

If you don't do hand calculations, then how would you verify computer output?

 

[ItsOnlyDirt]

Blind faith ?

 

[handex]

thanks for the responses guys. We usually dont use wallap and only use hand calcs. We originally did this wall with just hand calcs but the geotech engineer wanted us to use a wallap model taking into account soil deflections and excavation sequences.