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Abstract Silt-trap dam is an important debris flow preventive measure with a large cubage. According to the forms and circs of the dams summarized and a new notion of the system collocating optimization，the experiment on regulating properties of debris flow by the silt-trap dam has been performed. In the experiment，bulk density，gross and the rate of the drainage hole are changed to analyze the property variation law of debris flow. The experimental results show that：(1) The gradient of intercepted sediments increases with the increase of bulk density and gross of debris flow，and the decrease of rate of drainage hole. The bulk density is smaller，the effects of the gross and rate of drainage hole on the gradient are larger. (2) When the gross of the debris flow is less than the cubage，the value of the flux changing with a drainage hole rate 2.2% is twice to that with a rate 6.6%. (3) Under the same over-current of the drainage hole mode，the former bulk density gets a square formula relation with its ratio to the latter. With the formula，we find that when the bulk density is 1.567 kN/m3，the change of bulk density before and after experiment is the biggest. (4) The ratio of D50 between before and after the experiment is proposed to scale the selection property of the dam and compare the change of grain diameter. The dam gets the most evidently effect of leaving the coarse grain and passing the fine grain when the watery debris flow passes through the dam.
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Received: 22 April 2011
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2011, Vol. 30 
