Experimental Study on Wide-Graded Soil Transport in Unsteady Flow

A special study on the interaction mechanism between flow and soil is of great significance for revealing macro breaching barrier dams. To scouring characteristics wide-graded sediment under different conditions, flume scour tests were conducted regarding grading curve dam material discharge process Tangjiashan dam. The results show that: (1) narrow-graded or uniform sediments formation movement sand wave, while mode mainly formation, expansion, pit. (2) Under condition weak unsteady flow, surrounding shielding effect coarse particles fine obvious, erosion resistance strong. However, strong weak. (3) caused by slope angle collapse at initial stage, reflected traceable later stage. Therefore, in stage erosion, downstream intensity high, bed surface can easily form a inclined downstream. (4) greater than that steady flow. transport formula based cannot be used to calculate break directly.