EVALUATION OF DEBRIS FLOW DYNAMIC CHARACTERISTICS BY VIDEO MATERIALS

For mud dams construction it is necessary to clarify characteristics of debris flow such as flow velocity and pressure on the barrier. Determining these characteristics often causes difficulties due to the fact that debris flow is rather rare event and constant monitoring of them is carried out at mud flow observation station stations, which are few worldwide. Currently large number of videos have appeared on the Internet that captures debris flow descent. This material can be used to obtain not only qualitative, but also quantitative characteristics of the debris flow. In cases, when it is possible to determine the scale and specific location of debris flow on a video, measuring its velocity and other characteristics is a workable task. This research present an attempt to quantify the debris flow velocity based on the video materials with the subsequent comparison of the results obtained using various methods. The object of our study was the debris flow that came down in Austria, in Firgen on August 4, 2012. The survey was carried out from several angles, which made it possible to select a section of the channel to measure the velocity of debris flow wave train. Calculation of flow velocity and pressure on the barrier was conducted by several methods developed by various researchers. Debris flow velocities measured on the video are minimum – 7,4 m/s, maximum - 10 m/s. Differences between calculated by various methods and measured on the video values range from 0,1 m/s to 4,8 m/s.