基于深圳市东江水源工程,分析了影响沼蛤附着的因素,沼蛤入侵输水管道的特征和规律,以及沼蛤造成的生物污损对管壁的腐蚀程度。调查发现:沼蛤附着密度随着距取水口的距离成指数衰减,且水源能够影响的密度范围相差2~4个量级;如取水口后方无开敞或无压结构时,一般附着密度能够在距离取水口后方5~10km范围内迅速衰减到0;在同一压力结构段中沼蛤附着密度呈一致性衰减;当压力段遇到开敞水池或无压结构时,沼蛤的附着密度都会发生剧烈波动,密度变化范围相差1~2个量级。当水流流速长期高于1.2m/s,能够抑制壁面沼蛤附着,当水流偶然高流速高于2m/s时,壁面已经附着的沼蛤会被水流冲刷下来。沼蛤对管道结构壁面的腐蚀与其附着密度是互促增长的过程。
Based on the engineering background of the Limnoperna fortune invasion in Shen-zhen Dongjiang water source project,this paper analyzed the effecting factors of Limnoperna fortune adhering,the rules of the Limnoperna fortune invasion into water transmission pipe,and the corrosion intensity on pipe internal wall caused by Limnoperna fortune.The results showed:Limnoperna fortune adhering density decreased exponentially with the increase of the distance to water intake,and the adhering density affected by water source could vary about 2~4 magnitude;if the area after water intake is in exclusion from air or in unconfined flow,the Limnoperna fortune adhering density would decrease to zero in 5~10 kilometers;in the same pressure structure sphere,Limnoperna fortune adhering density would always decrease exponentially;when the pressure flow met the free water surface tank or no-pressure structure,Limnoperna fortune adhering density would vary intensively,and variance range would cover 1~2 magnitude.If the flow velocity was always higher than 1.2 m/s,Limnoperna fortune would not adhere to pipe inwall,but if the flow velocity was occasionally higher than 2 m/s,the adhered Limnoperna fortune would be washed off.The corrosion intensity and Limnoperna fortune adhering density was related with each other.