Finite element analysis of anchored sheet-pile wall

Abstract

For anchored sheet pile walls, the classical method of determining depth of penetration can be done using limit equilibrium. It uses log-spiral graphs to determine the appropriate KAH and KPH values with δ=0.66φ. These values are used for the horizontal pressures, which in turn allow horizontal forces to be determined.

Using moment equilibrium, the required depth of penetration can be solved and the tension force of the anchor can be calculated using equilibrium of forces. The location of zero shear and the magnitude of maximum moment can also be obtained. However, moment equilibrium does not consider stiffness of the wall, and the soil which affect the performance of the sheet-pile wall.

In this project, the behaviour of anchored sheet-pile walls was investigated using the finite element program, Plaxis. Plaxis incorporates the flexibility of the wall, and the non-linear behaviour of the soil. The focus of this project was to determine the effects of the stiffness and flexibility of the sheet-pile wall has on its bending moment profile, the location of maximum bending moment, wall deflection, and anchor forces. The friction angle of the soil is also considered on the effects it has on wall movement.

Results showed that horizontal pressure do not conform to the classical theory. The location of maximum moment does not coincide with limit equilibrium. There were indications of lateral pressure being redistributed, leading to moment re-distribution. The wall flexibility also influenced the failure of the active and passive wedge.