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Abstract In order to quantitatively analyze the intensity and variation of airblast generated by the movement of sliding mass，a rapid and long-runout landslide at Niujuangou was studied with a computational fluid dynamics(CFD) software incorporating the resistance along the movement path defined by the law of Voellmy. The numerical results revealed that the whole travelling process of sliding mass lasted about 112 s and the maximum speed at every moment appeared in the front zone of sliding mass with two peak values of 52 m/s at 9 s and 44 m/s at 49 s respectively. The maximum velocity of airblast of 45 m/s appeared at 9 s and the maximum pressure of airblast was 625 Pa，equivalent to a violent storm，and was generated at the moment when the sliding of mass was just initiated. The greatest squeezing effect of the sliding mass to the air ahead occurred when the sliding mass was in rigid motion. As the sliding mass fragmented，the airblast pressure in front of the sliding mass decreased with the reducing of the height of the front head of the slide slope. The farther away from the front of sliding mass，the lower the pressure was. The rugged path of sliding had a large influence on the distributions and magnitudes of the pressures of airblast. When the front of sliding mass arrived at the toe of a convex slope，positive pressures with large variation of gradient will be induced at windward side，and negative pressures was induced at leeward side. When the sliding mass bursts out the scarp，it violently squeezed the air ahead leading to a sharp increase of positive pressures.
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Received: 30 September 2013
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2014, Vol. 33 
