Abstract Structural countermeasures such as slit dams and check dams are widely installed in mountainous regions to mitigate debris-flow hazards. However, current approaches adopted to estimate debris-flow impact load only depend on the flow properties without considering the effect of structural geometry. To better understand the effect of slit size on the impact load experienced by debris-flow mitigation dams, a series of small-scale debris flows impact tests on modelled slit dams and check dams are conducted in an instrumented flume. Measurement of the flow velocity, depth, impact load, total basal normal stress, and basal pore-fluid pressure enable a comprehensive grasp of the impact details. Tests reveal that the peak frontal impact pressure is largely unaffected by the slit size of structural countermeasures but is sensitive to the debris-flow properties. However, the slit size obviously influences the peak force experienced by the structures. A critical relative slit size (ratio of slit size to the maximum particle diameter in the debris flow) of 3.6 is determined wherein slit dams can effectively mitigate debris-flow hazards. In addition, a simplified bilinear pressure distribution model is proposed for debris-flow impact load estimation of the slit dams and check dams.

中文翻译：

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狭缝尺寸对泥石流减缓坝冲击载荷的影响

摘要 在山区广泛设置裂隙坝、拦阻坝等结构对策以减轻泥石流灾害。然而，目前用于估计泥石流冲击载荷的方法仅依赖于流动特性，而没有考虑结构几何的影响。为了更好地了解狭缝尺寸对泥石流减缓坝所承受的冲击载荷的影响，在仪表化水槽中对模拟狭缝坝和止回坝进行了一系列小规模泥石流冲击试验。通过测量流速、深度、冲击载荷、总基础法向应力和基础孔隙流体压力，可以全面掌握冲击细节。测试表明，峰值正面冲击压力在很大程度上不受结构对抗措施狭缝尺寸的影响，但对泥石流特性很敏感。然而，狭缝尺寸显然会影响结构承受的峰值力。确定了 3.6 的临界相对狭缝尺寸（狭缝尺寸与泥石流中最大粒径的比率），其中狭缝坝可以有效减轻泥石流危害。此外，还提出了一种简化的双线性压力分布模型，用于估计狭缝坝和止闸坝的泥石流冲击载荷。图 6 确定了其中狭缝坝可以有效减轻泥石流危害。此外，还提出了一种简化的双线性压力分布模型，用于估计狭缝坝和止闸坝的泥石流冲击载荷。确定了图 6 中的狭缝坝可以有效地减轻泥石流危害。此外，还提出了一种简化的双线性压力分布模型，用于估计狭缝坝和止闸坝的泥石流冲击载荷。