汶川震区滑坡堆积体土石混合坡面细沟水动力学特征室内试验

Indoor experiments on eroding rills hydrodynamics characteristics of earth-rock mixed landslide slope in Wenchuan Earthquake area

野外测定汶川震区滑坡堆积体休止角、土石混合坡面容重、土壤（〈2 mm）与碎石（2-7 mm）比例，以此作为模拟研究的参数范围，开展了室内土石混合高陡坡面放水冲刷试验，研究了不同流量、坡度与石土比例组合下的水动力学特征。结果表明：34°坡面各流量及36°坡面4 L/min组合下，全土情况的水流流速均显著大于含碎石情况下的水流流速，在36°坡面8 L/min，12 L/min情况下，含碎石情况的水流流速逐渐增大并超过全土情况；各组合水流流速均随冲刷时间的延长而减小。石土比例对雷诺数 Re的影响较复杂，在试验时段内各组合的水流基本属于过渡流或紊流。石土比例对弗劳德数 Fr的影响规律与流速相似，Fr随冲刷时间延长而逐渐从急流转变为缓流，其中含碎石情况相比全土情况表现更加明显。Darcy-weisbach阻力系数 f 随冲刷时间先缓慢增加后迅速增加再急速下降，全土情况下的 f值介于0.16~14.40，含碎石情况下 f值介于0.16~29.68。Darcy-weisbach阻力系数 f与 Re呈负相关关系。

A set of indoor experiments on earth-rock mixed steep slope with scouring flow method were conducted, and then the rill hydrodynamics characteristics under different flow rates, slopes, ratio of earth and rock contents were measured based on the angle of repose, bulk density, and ratio of earth and rocks that measured in the field investigation. The results show that under each flow rate of 34° and 4L/min of 36°,the average flow velocities under earth are significant higher than that of earth-rocks mixed. Under the 8 L/min and 12 L/min of 36° , the average flow rates increase gradually and become higher than that of earth. The average flow velocities under all of the groups decrease with the scouring times flies. The ratio of earth-rocks affecting the Reynolds number is complex. The flow regime is almost transition flow and tur-bulent flow during the experimental time. The influence of ratio of earth and rocks on Froude number has the same rules with that on average flow rates. As time goes on,Froude number transforms from supercriti-cal flow to subcritical flow, especially the changes are obvious under the earth and rocks mixed. Dar-cy-weisbach friction increases slowly, and then increases rapidly, decreases sharply at last with scouring time flies. The Froude number is 0.16~14.40 under the earth and 0.16~29.68 under earth and rocks mixed. Darcy-weisbach friction has negative correlation with Reynolds number.