A 3D numerical simulation of oblique bending in a steel sheet pile wall - A quantification of soil influence

Abstract

In geotechnical practice frequently use is made of steel sheet pile walls for soil and/or water retaining constructions. High demands are made with respect to the deformations, in particular in urban surroundings. Often these walls are composed of V- or Z-shaped profiles, whereby both profiles have their specific advantages and disadvantages. A common used variant is a sheet pile wall composed of so called double If-profiles. A double If-profile is made up of two single U-profiles which are connected by welding or crimping. A very specific property of the double If-profile is the rotation of the neutral axis. As a result of that, the sheet pile wall tends to deflect both in forward (lateral) direction as well as in sideway (transverse) direction. This phenomenon is called oblique bending, and it results in a loss of stiffness and strength (compared to a continuous wall) and thus larger deformations. Oblique bending goes together with slip in the free interlocks and a transverse deflection of the sheet pile wall relative to the soil body. Oblique bending might be influenced by the transverse bearing capacity of the soil, i.e. the soil reduces or even prevents the transverse deformation of the sheet pile. Besides, the shear stress in the free interlock possibly reduces oblique bending. The main goal of this study is to determine the transverse bearing capacity of the soil. Therefore a three dimensional finite element model is made of a cantilever sheet pile wall with a dry excavation in front and without friction in the sliding interlocks. This is a 'worst case' model, i.e. if a sheet pile wall is modelled in this way, oblique bending can be observed most clearly. Emphasis has been put on the generation of an appropriate mesh which is also useful for further investigations regarding oblique bending. Use is made of the finite element system DIANA, version 6.1.