砂质河床与砾石河床的河型判别研究

砂质河床与砾石河床在水力学特征与泥沙运动特征方面都有较大差异，由此导致了河型特征的差异。本研究以世界上近200条河流的资料为基础，在建立同时适用于砂质与砾石河床河型判别统一关系方面进行了尝试。以水流切力、河流功率以及无量纲切力Sd/D50来表示水流强度，而以宽深比和无量纲河宽来间接反映河岸约束性，从而在一定程度上克服了河岸约束性难以定量表达的困难。研究发现，上述水流强度变量和河岸约束性变量的组合关系，在具有不同河型的砂质与砾石河床之间表现出较大的差异，从而实现了对砂质河床与砾石河床河型的定量判别，得到了一系列的沙质与砾石河床河型的判别关系。

Channel pattern discrimination for sandy bed rivers and gravelly bed rivers

Based on the data obtained from 200 rivers, the universal discrimination equations of channel pattern both for sandy bed rivers and gravelly bed rivers and established. The flow shear stress, stream power and dimensionless flow stress are used to express the flow strength of the river. The ratio of channel width to depth and a dimensionless channel width index are used to reflect the constraint of riverbank on stream flow, thereby to overcome the difficulty that the bank constraint cannot be expressed quantitatively. It is found that the relationships between the flow strength variables and riverbank constraint variables exhibit remarkable difference in sandy bed rivers and gravelly bed rivers. Accordingly, a series of discrimination equations both for sandy bed rivers and gravelly bed rivers are proposed.