Study on the Thickness Ratio Effect and Energy Evolution Laws of High-Performance Shotcrete

The internal energy evolution process and mechanism of high-performance fiber-reinforced shotcrete single-layer lining during layered construction remain unclear. To investigate the influence of layered construction on the energy evolution characteristics of the single-layer lining structure, this study conducted uniaxial compression strength tests on specimens with six different thickness ratios (the thickness ratio of the second layer to the first layer of fiber-reinforced shotcrete). The results indicate that: The uniaxial compression strength of fiber-reinforced shotcrete is significantly affected by the thickness ratio. The peak strength reaches its maximum value of 43.32 MPa when the thickness ratio is 1, with an optimal stress distribution. When the thickness ratio exceeds 4, debonding and crushing phenomena occur due to the excessive thinness of the lower layer. During the uniaxial compression process, the total input energy of the specimens increases with the thickness ratio. The elastic energy storage capacity is optimal at a thickness ratio of 1, while the dissipated energy exhibits significant fluctuations at a thickness ratio of 5, reflecting concentrated energy release due to local instability. Based on the energy dissipation coefficient analysis, the energy dissipation rate decreases during the compaction stage, indicating a significant reduction in structural stability.