植草衬砌渠道水力计算及应用探讨

Hydraulic calculation and engineering application of grass-lined channels

在城市化过程中,许多自然河道被截弯取直和硬化,变为"三面光"渠道,造成水生态破坏和水环境恶化。海绵城市建设要求对已经渠化的河道进行生态岸线改造,但由于我国相关基础理论较为薄弱,各地对生态岸线改造均持谨慎态度。在此背景下,引入美国农业部和联邦公路管理局有关植草衬砌渠道设计相关理论,同时针对我国城市用地紧张、渠道边坡系数较小的特点,对美国计算理论中的最大允许剪应力进行修正。为帮助理解植草衬砌渠道水力计算过程,构造一个生态岸线改造案例,通过侵占河道两侧绿线,实现了生态岸线改造后排水能力不低于改造前的目标。

In the process of urbanization, many natural rivers have been transformed into rigid lining channels, causing ecological destruction and water environment deterioration. The construction of sponge city requires the ecological restoration of channels that have been rigidly lined. However, the channel restoration work is progressing slowly in many parts of China due to the lack of theoretical basis. In this context, the grass-lined channel design theories are introduced, which are published by the United States Department of Agriculture and Federal Highway Administration. As the land resources are insufficient in many cities of China, the channel side slope is relatively steeper than in Unital States. To fit these situations, the permissible soil shear stress in American theories is modified. An example of channel restoration is provided for helping understand the hydraulic calculation process of grass-lined channels. By encroaching on the channel’s green line in the example, the flow capacity of post-reconstruction is not lower than that of pre-reconstruction.