复杂水流条件下抛石漂移距离的试验研究

Experimental study on drift distance of riprap on the condition of complex water flow

抛石漂移是河道治理、护岸、潜丁坝、桥墩防冲等实际工程中经常遇到的问题,依托长江南京以下12.5 m深水航道二期工程口岸直水道整治工程,针对抛石漂移距离在试验室水槽内开展了一系列物理模型试验,对水深、流速、抛高、块石质量及块石形状的不规则等因素对抛石漂距的影响进行了研究;同时在考虑水流流速垂向分布的基础上,通过块石在动水中的受力分析推导出水上抛石漂移距离计算公式,利用模型试验结果拟合出公式中各系数的值,并将其计算结果与模型试验数据和现场观测数据进行比较,结果吻合较好,验证了公式的合理性。

Drift distance of riprap is a problem encountered frequently in works of river channel regulation, river regulation, bank protection, submerged deepwater channel phase Ⅱ project of Kou＇an dike construction and pier scour protection. Relying on 12. 5 m straight reach along the Yangtze River downstream Nanjing, a series of experiments have been conducted to investigate the effect of water depth, flow velocity, throwing height, rock mass and irregularly shaped foundation of rock on drift distance of riprap.Furthermore, a formula for calculating throwing distance of riprap is given based on hydraulic equilibrium equations which describes riprap movement by considering the vertical distribution of flow velocity.The coefficients in the calculating formula are obtained by curve fitting using the data from experiments. Reasonable agreement of calculated results with model experiment and field observation results verified the reliability of the model.