Channel morphology and bed sediment erodibility are two crucial factors that significantly affect debris flow entrainment processes. Current debris flow entrainment models mostly hypothesize the erodible beds are infinite with uniform slopes. In this study, a series of small-scale flume experiments were conducted to investigate the effects of bed longitudinal inflexion and sediment porosity on basal entrainment characteristics. Experimental observations revealed that sediment entrainment is negligible at early stages and accelerates rapidly as several erosion points appear. Continual evolution of flow-bed interfaces changes interactions between debris flows and bed sediments, rendering the interfacial shear action involved into a mixed shear and frontal collisional action. Lower bed sediment porosity will change the spatial arrangement and orientation of particle mixture, strengthen the interlocking and anti-slide forces of adjacent sediment particles, and promote the formation of particle clusters, all of which will increase bed sediment resistance to erosion. By examining the post-experimental bed morphology, the slope-cutting amounts and topographic reliefs are determined to positively correlate with longitudinal transition angles. These high topographic reliefs may indicate the propensity of triangular slab erosion, rather than strip-shaped slab erosion, in non-uniform channels with relatively steep erodible beds. Empirical formulas are obtained that denote the relationships among bed sediment strength, channel curvature radius, and sediment porosity through a multi-parameter regression analysis. This study may aid in clarifying the complex coupling effects of spatial variations in debris flow dynamics as well as sediment erodibility and bed morphology in non-uniform channels with abundant seismic loose material.

河道的形态和床层沉积物的可蚀性是两个重要因素，它们显着影响泥石流的夹带过程。当前的泥石流夹带模型主要假设可蚀床层是无限的，且坡度均匀。在这项研究中，进行了一系列的小型水槽实验，以研究床的纵向弯曲和沉积物孔隙度对基底夹带特征的影响。实验观察表明，泥沙夹带在早期可以忽略不计，并且随着出现几个侵蚀点而迅速加速。流化床界面的不断演化改变了泥石流与床层沉积物之间的相互作用，使界面剪切作用变成了混合剪切和正面碰撞作用。较低的床沉积物孔隙度将改变颗粒混合物的空间排列和方向，增强相邻沉积物颗粒的连锁和防滑力，并促进颗粒团簇的形成，所有这些都将增加床沉积物的抗侵蚀性。通过检查实验后的床层形态，确定切坡量和地形起伏与纵向过渡角成正相关。这些高地形起伏可能表明，在具有相对陡峭易蚀床层的非均匀通道中，三角形板状侵蚀的倾向性大于条形板状侵蚀的倾向。通过多参数回归分析获得了经验公式，这些公式表示了床沉积物强度，通道曲率半径和沉积物孔隙率之间的关系。