碎裂岩体失稳产生涌浪原型物理相似试验研究

PROTOTYPE PHYSICAL SIMILARITY EXPERIMENTAL STUDY OF IMPULSIVE WAVE GENERATED BY CATACLASTIC ROCKMASS FAILURE

崩滑体涌浪事件具有突发性和灾难性,且实测资料有限,原型物理相似试验研究这种涌浪现象是很好的方法。以三峡库区龚家方崩滑体涌浪事件为原型,探索构建三峡水库蓄水后干流上第一个涌浪大型物理相似试验模型,其长24 m,宽8 m,高1.3 m,几何相似比为1∶200。试验采用大理石材质、d50=1.47 mm的粗砂模拟碎裂岩体,利用波高仪、高速摄影机和爬高测试带监测河道内的水波变化过程,实施了以前缘入水速度为变量的6组涌浪试验。试验结果与龚家方涌浪事件调查结果对比表明,该试验方法可用于预测和研究类似碎裂岩体失稳产生涌浪问题。系列试验分析后,首次通过数据展示碎裂岩体失稳产生的涌浪在传播过程中波的追逐、叠加及反射波叠加等相互作用过程,精细地刻画了河道内涌浪传播和爬高衰减率的差异性。通过该原型模型系列试验,探讨碎裂岩体失稳产生涌浪模型试验的改进方向。采用的物理相似试验方法为碎裂岩体失稳产生涌浪研究提供了很好的借鉴,试验得到的数据及规律认识将为三峡库区类似岩质岸坡失稳产生涌浪预测提供极大的技术支撑。

Impulsive wave events generated by landslides have the sudden and catastrophic characteristics, for which investigation information is very limited; so prototype physical experiment study is a good method in this condition. Taking impulsive wave event of Gongjiafang slump mass in Three Gorge reservoir area for the prototype, a big physical similarity model with the length of 24 m, width of 8 m, height of 1.3 m, is established, which is the first prototype model on main stream after the reservoir impounding. The model similarity ratio is 1 ： 200. Marble grit（ds0 = 1.47 mm） is used to simulate cataclastic rockmass in the test, using 15 wave gauges, high-speed cameras and run-up instruments to monitor wave process; and six sets of impulsive wave tests with the variable of impulse velocity into water in the front of the landslide are conducted. The comparison between test results and investigation results showthat the test method can be used to study or forecast impulsive wave generated by similar cataclastic rockmass failure. After analyzing a series of test data, waves interactive process is showed firstly with the help ofthe gauge data, for example, wave chasing, superposition and reflection wave superposition. The data also finely portrait the wave propagation and run-up decay ratio in the riverway. Through this prototype model test, the improvement direction of the experiment on impulsive wave generated by cataclastic rockmass failure is discussed. The method used in this paper can offer references for impulsive wave generated by cataclastic rockmass failure, and the results obtained can provide great technical support for forecasting impulsive wave generated by other similar slopes of Three Gorges reservoir area.