A study of sheet pile quay wall rehabilitation methods

Abstract

This paper studies numerically a tied-back sheet pile quay wall failure in Egypt, which started to collapse after the completion of the superstructure. The quay wall comprises a 20 m length sheet pile wall tied back to a 6 m length sheet pile wall. The failure of the tied-back sheet pile wall occurred in the tie rods, resulting in about 15 cm displacement. The explanation of failure required underwater dive inspection to investigate the cause. Investigations have revealed the absence of waler beams installation at the level of tie rods which led to their loss. And thus, the failure was attributed to the design errors and the tie rod bolts' poor material quality. This research aims to provide common rehabilitation strategies that are little disruptive. An inverted U-slab approach has been suggested to restrict the sheet pile wall's lateral displacement. The U-slab approach consists of a 40 cm thick slab connected to a beam from the seaside and a deadman from the landside which provides a tie-back mechanism and strengthens the defective sheet pile wall. The study also investigates the behavior of the sheet pile wall before and after the tie-rods numerically by PLAXIS 2D. Based on the analysis, the U-slab technique results in 2 cm lateral displacement of the defective sheet pile wall in the operational phase. This means that the technique controls the lateral movement of the displaced sheet pile wall. Eventually, the approach satisfies the factor of safety and increases the friction between the slab and soil.

Keywords

• quay wall
• anchored sheet pile
• rehabilitation techniques
• plaxis