Picket anchoring systems in trench rescue operations

Abstract Background Trenching and excavation work continues to be among the most lethal activities in the construction sector with trench collapses presenting extreme hazards to both workers and rescuers. Current trench rescue practices rely on consensus-based guidance rather than validated engineering data. Picket anchoring systems are widely used to stabilize trenches during rescue operations. However, their performance remains poorly characterized with existing practices derived largely from non-geotechnical applications. This disconnect has left firefighters with Trench Rescue Technician certifications with limited scientifically defensible tools to assess soil conditions and anchoring capacity within the narrow time window available for life-saving rescue operations. Results This study introduces the Soil Density for Picket Test (SDPT) as a testing protocol enabling firefighters to rapidly assess near-surface soil types using standard equipment available on-site. Results demonstrate that the SDPT sledgehammer strike counts correlate closely with well-accepted results from the Standard Penetration Test (SPT). Results from the capacity per picket (CPP) test quantified conservative allowable capacities for standard picket installations across the range of near-surface soils that will be encountered in trench rescue operations. The incorporation of a picket box was shown to substantially increase capacities (CPP b ) and markedly reduce picket deformation, often reaching the limits of the testing apparatus before the failure criteria was achieved. The observed agreements between the SDPT, CPP, and CPP b results with the accepted norms established from SPTs provides strong validation of the proposed methodology across diverse soils, geological regions and climatic conditions. Conclusions By translating engineering principles into an operationally realistic protocol, this study bridges a critical gap between trench rescue operations and geotechnical engineering theory. This results in improved safety and decision-making in the high-stress, limited-resource conditions associated with trench rescue operations.