粘性泥石流弯道超高在流速计算中的应用

泥石流的流速是泥石流运动学研究的主要内容之一 ,也是泥石流工程防治必备的基本参数。前人已提出若干计算模式 ,计算值的误差因缺少验证的手段无法分析。作者提出的弯道超高现象用于泥石流流速的计算 ,一方面提供了一种以泥石流现象为基础的流速计算方法 ,另一方面也提供了一种泥石流流速的验证方法。该文应用物体作离心圆周运动的物理学基本原理和方程 ,推出泥石流弯道运动的速度与弯道曲率半径的关系 ;同时分析出泥石流弯道超高的本质原因为泥石流凹岸与凸岸的速度差产生的动能差所致 ,即可建立动能与超高势能的平衡方程。联立方程即可分别求出凹岸和凸岸的泥石流流速 ,流速由凹岸向凸岸逐渐增加 ,取其平均值即为泥石流的平均流速。以滇东北蒋家沟一支沟大凹子沟 1994年 6月 16日的一场泥石流的弯道超高测量分析为例验证 ,获得初步成功。结合其他参数的测量可计算流量并分析泥石流的加速或减速的运动过程。

APPLICATION OF DEBRIS FLOW OVERSTEP IN CURVE WAYS TO VELOCITY CALCULATION

Debris flow velocity is the main research topic in debris flow dynamics and also the necessary basic parameter in debris flow engineering. For debris flow velocity, a lot of calculation models have been suggested. But how to check the model and the velocity calculation error are very important. In this paper, the debris flow overstep from concave to convex banks in curve ways is suggested to be used in calculating and checking the debris flow velocity. In fact, the basic principles and formulas of circular motion are used in this paper. Therefore , the relationship formula between the velocity and curve way radius is set up. Besides, as the debris flow overstep in concave banks, lower in convex banks, origin from the difference of debris flow velocity and its kinetic energy on both banks, in terms of the balance of overstep potential energy and kinetic energy, another formula about both the velocity of debris flow on convex and concave banks and the overstep height can be also set up. Unite the two formulas above, the debris flow velocity on both convex and concave banks can be obtained . As usual, the debris flow velocity increases from concave bank to convex bank, and the average velocity of debris flow can be gotten smoothly. These ways are used in Daaozi gully debris flow velocity calculation on June 16, 1994 to check the reliability of the method above. From the data, it is clear that the method used in debris flow velocity calculation is wonderful and the discharge and debris flow dynamics processes can be also known by getting some other section data.