Abstract
The size of a debris flow will increase if bed material is entrained into the flow body. The erosion velocity or entrainment rate can be predicted if the torrent bed sediment is the same as that of debris flow body. However, such cases are rare. The present paper describes the entrainnig characteristics of bed sediment into debris flow body based on flume tests. Experimental results show that the entrainment/erosion velocity decreases with the sediment size ratio, d/d0, in which d is the bed sediment size and d0 is the grain size of the supplied debris flow. The critical grain size of entrainment depends on the relative flow depth, h0/d0, in which h0 is the debris flow depth.
