The sediment transport capacity (T_c) is an important parameter for analysing and controlling soil erosion processes. However, few studies have investigated the T_c of soils containing gravel (grain sizes of >2 mm) on steep slopes. Colluvial deposits on steep slopes in benggang are composed of loose materials with large amounts of gravel. This study aimed to investigate the effects of gravel content on the T_c of overland flow using colluvial deposits with a range of slope gradients and flow discharges in a nonerodible flume (4 m long, 0.12 m wide and 0.1 m high). The experiments were carried out using six gravel mass contents (0, 10, 20, 30, 40, and 50%), four slope gradients (18, 36, 57, and 84%), and four flow discharges (0. 56, 1.11, 2.22, and 4.44 × 10^-3 m² s⁻¹). The experimental results revealed that the measured T_c increased linearly as the gravel content increased. The effects of the slope gradient, flow discharge and gravel content on T_c were significant (p < 0.01). T_c increased following power functions either with slope gradient, flow discharge and gravel content (coefficient of model determination (r²) = 0.96 and Nash-Sutcliffe model efficiency (NSE) = 0.96), or with slope gradient, flow discharge and sediment median grain size (d₅₀) (r² = 0.98 and NSE = 0.98). The two established power functions facilitated the prediction of the T_c of colluvial deposits in this study. However, the power functions overestimated the predicted T_c values when the measured T_c was less than 1 kg m⁻¹ s⁻¹ and underestimated the values when the measured T_c ranged from 2 to 4 kg m⁻¹ s⁻¹. These findings are helpful for improving the simulation of erosion processes in colluvial deposits and deepening the understanding of erosion mechanisms in soil and rock mixtures. Moreover, the relationship of hydrodynamic variables with T_c on colluvial deposits remains to be investigated in additional in-depth studies.

输沙能力（T _c）是分析和控制土壤侵蚀过程的重要参数。但是，很少有研究调查陡坡上含砾石（粒度> 2 mm）的土壤的T _c。蚌港陡坡上的冲积沉积物是由松散的物质和大量的砾石组成的。这项研究旨在调查砾石含量对T _c的影响使用具有一定坡度梯度的坡向沉积物和不易侵蚀的水槽（长4 m，宽0.12 m，高0.1 m）中的流量排放来进行陆流。使用六种砾石质量含量（0％，10％，20％，30％，40％和50％），四个坡度梯度（18％，36％，57％和84％）和四个流量排放（0. 56，％）进行实验。 1.11、2.22和4.44×10 ^-3  m ²  s ^-1）。实验结果表明，随着砾石含量的增加，测得的T _c呈线性增加。坡度，流量和砾石含量对T _c的影响均显着（p  <0.01）。Ť _ç随幂函数的增加随坡度，流量和砾石含量（模型确定系数（r ²）= 0.96，纳什-苏特克利夫模型效率（NSE）= 0.96）或坡度，流量和沉积物中值粒径而增加（d ₅₀）（r ²  ＝ 0.98和NSE  ＝ 0.98）。在这项研究中，两个已建立的幂函数促进了对冲积沉积物T _c的预测。但是，当测得的T _c小于1 kg m ^-1  s时，幂函数高估了预测的T _c值^-1并低估了当测量的T _c为2至4 kg m ^-1  s ^-1时的值。这些发现有助于改善对冲积沉积物侵蚀过程的模拟，并加深对土壤和岩石混合物中侵蚀机理的理解。此外，在冲积沉积物上流体动力学变量与T _c的关系还有待进一步深入研究。