山区小流域泥石流冲蚀槽形成的力学研究

Study on the Mechanics of the Forming of Mudslide Erosion Groove in Small Watershed of Mountainous Area

山区公路等级低,小流域沟谷产生的泥石流冲蚀凹岸路基土,造成路面坍塌,从而影响山区道路的通行.在台风暴雨作用下,对野外泥石流冲蚀路基土的力学机理研究较少.通过模拟泥石流沟,采用两种不同类型的泥石流冲刷路基,采用路基土模拟沟谷凹岸.模拟试验发现:黏性泥石流冲蚀掏空凹岸路基土的时间比稀性泥石流冲蚀掏空凹岸路基土的时间长.泥石流冲蚀路基时,总是先形成小的冲蚀槽,然后再继续扩大,进而掏空路基;采用条分法建立泥石流冲蚀路基形成小冲蚀槽的力学原理模型,根据泥石流的冲击力,通过临界状态分析确定了冲蚀形成的冲蚀槽弧长,试验结果与野外现象相一致.

Highway classification in mountainous area is lower and the mudslide in small watershed hollowing roadbed of concave bank causes road surface collapse.Under the field condition and the action of typhoon rainstorm,it is hard to study the mechanics of subgrade erosion.By simulated mudslide gully,two different types of mudslide are used to erode the subgrade soils and the concave bank of gully is simulated by gravelly soils.The results show that the ability of erosion and entrainment,less viscosity mudslide is stronger than viscous mudslide.Viscous mudslide that erodes roadbed is more quickly than less viscosity ones.First small erosion channels are formed when mudslide erodes the roadbed,and then the small erosion channels increase.Finally,the roadbed is hollowed.Based on the slice method,the simplified physics model is established.Impact force is confirmed through the stability analysis and the test results are consistent with field phenomenon.