In cantilever sheet pile wall construction, heavy sheet pile are driven into the ground prior to excavation taking place. When excavation is carried out, the soil behind the sheets is retained by their cantilever action.
Cantilever sheet pile walls tend to be prone to movement and are generally only used for temporary structures or for permanent walls of low height in sands and gravels.
In addition to the above, there are also two other important criteria that are adopted in practical design of sheet pile walls as follows:
1. An additional depth is allowed at the front of the wall to allow for the possibility that an accidental excavation may occur here.
suggests that this allowance should be 10% of the retained height up to a maximum allowance of 0.5m.
2. A surcharge load is applied behind the wall to allow for loading in this area. The applied surcharge will depend on the load that might be expected, but general practice allows for a minimum nominal surcharge of 10 kN/m2.
Design of Cantilever Walls by Moment Balance
Design of cantilever walls is carried out by finding a moment balance about the assumed point of fixity. As has been discussed previously, generation of full active and passive pressure requires a certain strain to develop in the soil. Generation of full passive resistance will, in particular, require quite significant strains to develop. Several different design methods have been proposed for cantilever retaining walls depending on different assumptions of precisely what earth pressures are mobilised.
This article comes from academia edit released