河(渠)道越来越多采用植草衬砌,它不仅保护河渠岸坡免受冲蚀,还改善生态条件,然而,植物对水流产生拖曳力从而影响河道过流能力.讨论了植物衬砌抗冲蚀效应的主要影响因素,提出了评估植草衬砌河渠稳定性的方法,根据水流拖曳有效剪应力与土壤允许有效剪应力之间的极限平衡条件导出了估算植草衬砌渠道过流能力的公式.实例计算研究表明,百喜草和狗牙根草因其较强的抗冲蚀性和较小的阻水性而比较适合于我国南方河渠衬砌.
Grass-linings are more and more being adopted in canals and channels,which can not only protect the boundary soils from erosion,but also improve the channel ecological condition.However,vegetation in open channels retards the flow of water by exerting additional drag force on the moving fluid.In this paper,the main factors that influencing on erosion-resistant effect of vegetative linings are discussed;and a method to evaluate the stability of grass-lined channels is proposed.Based on the limit equilibrium between the effective shear stress on the soil,which caused by water flow and exerted by the vegetation,and the allowable effective shear stress of the soil,an equation for estimating the discharge of grass-lined channels is developed.A case study shows that paspalum notatum and cynodon dactylon are suitable for grass-linings of channels in Southern China owing to their notable erosion-resistance and less flow resistance.