Determination of the drift distance of a riprap is critical for water riprap works.Most of researchers have focused on the drift distance of a single particle rock so far,and a systematic study on the drift distance of a rock group was rarely carried out.It remains to be verified whether the drift distance of a rock with an average mass can represent that of a rock group.In this paper,a series of experiments have been conducted to investigate the drift and diffusion of a rock group with different mass combinations under different water depths and flow velocities.Comparisons between the calculated drift distance of the rock with an average mass using the formula for a single particle rock and the average drift distance of the rock group from the experiments were curried out.The results show that the drift distanceof the rock with an average mass is close with that of the rock group if the water depth is less than 15m while the drift distance of the rock with an average mass is greater than that of the rock group if the water depth is around 30m.Furthermore,a formula for calculating the distribution area of a rock group riprap was derived through dimensional analysis.Reasonable agreement of the calculated results between the model experiment and field observations verified the reliability of the calculating formula.%为研究混合石料群抛入水后的漂移与扩散情况,在试验室水槽内开展了不同水深、不同流速、不同质量组成的混合石料群抛试验.将单颗粒抛石漂移距离公式计算结果与混合石料群抛平均漂移距离进行比较,结果表明:当水深在15m以内时,具有平均质量的单颗粒块石漂移距离与群抛试验平均漂移距离较为接近;当水深为30m时,具有混合石料平均质量的单颗粒块石漂移距离明显大于群抛试验平均漂移距离;群抛与单抛漂移距离的偏差随流速的增大而增大.同时通过量纲分析得到了混合石料群抛水下分布面积计算公式,并将计算结果与实验室试验数据和现场观测数据进行比较,吻合较好.
展开▼
