冲积河流河床演变的滞后响应模型-Ⅰ模型建立

Delayed response model for fluvial processes of alluvial rivers-Ⅰ model development

滞后响应是冲积河流河床演变中的一种普遍现象,也是研究冲积河流河床演变规律的关键因素之一。本文基于冲积河流自动调整的基本原理,根据河床在受到外部扰动后的调整速率与河床当前状态和平衡状态之间的差值成正比的基本规律,首先建立了河床演变滞后响应的基本模型,进而建立了适用于不同条件的计算模式,包括通用积分模式、单步解析模式和多步递推模式等。建立的滞后响应模型和计算模式既能描述滞后响应现象又能反映前期累计影响,为定量描述河床特征变量随时间的响应过程提供了理论基础和计算方法。

Delayed response is a phenomenon that commonly occurs in fluvial processes of alluvial rivers, and therefore it is a key factor that needs to be considered in the study of channel adjustment. Due to the selfadjustment mechanism of geomorphie systems, the rate of adjustment in response to a disruption is proportional to the difference between the actual state and the equilibrium state. Based on this principle, a delayed response model for channel adjustment was proposed. Then calculation methods were developed, including the general integration method, the single-step analytical solution method, and the multistep iterative method. Both the delayed phenomenon and the cumulative effect can be described by the proposed delayed response model and the calculation methods, which provide the theoretical base and calculation methods for quantitative description of the temporal variation of channel response variable.