植被护坡抗冲模型试验方法与装置研究

Method and equipment of model test for scouring resistance of riverbank with grass cover

基于模型和原体草皮冲刷破坏时床面切应力和摩阻流速应该相等原理,研制了一套可用于模拟实际河道中的大流速冲刷水流,并测定冲刷过程中植被水力学参数的试验装置.理论分析表明,水槽设计高度对植被区的床面切应力值不存在主导性影响.试验测得的有机玻璃水槽和草皮表面曼宁糙率系数值,以及试验土壤起动流速结果证明所设计的试验装置和方法是合理可行的.在此基础上进行了植被护坡抗冲模型试验,得出了草皮护坡破坏的临界水流条件.

Based on the principle that the bed shear stress and friction velocity of the grass cover in the model should equal those of actual condition in which grass cover is destroyed due to scouring, an experimental equipment was designed to simulate the scouring flow with high velocity in actual rivers and to measure the hydraulic parameters during the scouring process. Theoretic analysis proves that the design depth of the flume has no dominant effects on the shear stress on the vegetative bed. The hydraulic roughness of the plexiglass-flume and vegetation and the incipient velocities of soils indicate that the experimental equipment and method are reasonable and reliable. A model experiment on scouring resistance of a riverbank with grass cover was carried out, and the critical flow condition of destruction was obtained.