Enhancing barricade design in cemented paste backfill: Rheology, slab theory, and strength fusion

As a critical safety structure in cemented paste backfill (CPB) systems, traditional reinforced-concrete barricades exhibit high load-bearing capacity but suffer from design limitations due to the neglect of slurry rheological properties and time-dependent characteristics, leading to structural failures and resource inefficiency. This study proposes a lateral pressure theoretical model incorporating rheological time dependence, grounded in the yield stress-resting time evolution of CPB. Results demonstrate that backfilling height predominantly governs lateral pressure. A mechanical reinforcement model was developed using the plastic hinge line theory of two-way slabs, deriving computational formulas for horizontal and vertical reinforcement quantities. Key findings indicate that reinforcement requirements are influenced by backfilling height, width-to-height ratio (W/H), rebar diameter, and strength, while the horizontal/vertical reinforcement ratio solely depends on W/H. A strength fusion theory, integrating reinforcement area ratios through limit state design methodology, reveals that composite strength is primarily determined by rebar tensile strength, concrete unconfined compressive strength (UCS), and reinforcement area ratio, with concrete UCS being the dominant factor. This theory enables thickness determination based on structural strength characteristics, enhancing scientific rigor. The systematic design framework sequentially calculates lateral pressure, structural thickness, and reinforcement configuration. Case validations confirm 28%–35% reductions in concrete consumption and a 1–2 specification grade decrease in rebar diameters, while field applications demonstrate stable barricade performance during backfilling operations.