Effective Stabilisation Methods for Seawall Foundations: A Systematic Review Protocol

Seawalls are widely used hard-engineering structures for coastal protection, yet their long-term performance depends on foundation stability, which is often compromised by toe scour. Although a range of stabilisation approaches, including field interventions, laboratory and numerical modelling, and nature-based solutions, have been investigated, this evidence remains fragmented and has not yet been systematically synthesised for seawall foundations specifically. This systematic review therefore aims to identify, classify, and evaluate stabilisation methods for seawall foundations, with specific objectives to synthesise field-based methods, review laboratory investigations of stabilisation mechanisms and performance, evaluate numerical modelling approaches, and assess the effectiveness of nature-based solutions across field, laboratory, and numerical studies. The systematic review will be conducted according to the PRISMA guidelines. This protocol is registered on the Open Science Framework (https://osf.io/vfnx2) and is reported according to the PRISMA-P checklist. A comprehensive search will be conducted in Scopus, Web of Science, ScienceDirect, OpenThesis and ProQuest for studies published between 2016 and November 2026, with eligibility criteria defined using a novel Concept-Outcomes-Study (COS) framework. Two independent reviewers will screen studies using Rayyan, extract data using a piloted form, and appraise quality using a newly developed checklist, and findings will be synthesised narratively in tables and figures. To the reviewers’ knowledge, this review will provide the first integrated synthesis of seawall foundation stabilisation strategies across engineering and nature-based approaches, clarifying comparative effectiveness, identifying evidence gaps, and informing evidence-based, climate-adapted coastal defence design.