为了解浅水湖泊水体中颗粒悬浮物的静沉降规律,以太湖为例,采用重复深度吸管法计算了2005年4月、5月间在太湖进行的4次静沉降模拟实验中的沉降速度。结果表明:①在悬浮物沉降过程内,3种颗粒物的沉速关系为颗粒无机物(PIM)〉悬浮物(SS)〉颗粒有机物(POM)。在相同的沉降时间内,P1M的沉速为船沉速的1.6~2.0倍,POM的沉速为船沉速的0.3~0.7倍,P1M的沉速为POM沉速的2.5~5.5倍;②水体中悬浮物浓度与沉降时间均呈现出明显的指数衰减规律,悬浮物中无机物含量较高时这种规律更为明显;③悬浮物浓度较低时,太湖悬浮物的沉降速率与水体中的悬浮物浓度无明显的相关关系;而悬浮物浓度较高时,沉降速率随悬浮物浓度升高而增大。
In order to study the hydrostatic settling of suspended matter of large shallow lake, Four experiments, based on the Taihu lake, were conducted in the laboratory for hydrostatic settling behavior of suspended matter in Taihu lake in April and May, 2005. The settling velocity of suspended matter was calculated by McLa velocity of particular inorganic matter (PIM) is the biggest, and the second biggest method. The results show that the settling one is that of suspended matter (SS), the smallest one is that of particular organic matter (POM). During the same time of settling, the settling velocity of PIM is 1.6 - 2.0 times bigger than that of SS, the settling velocity of POM is 0.3-0.7 times bigger than that of SS, and the settling velocity of PIM is 2.5 - 5.5 times bigger than that of POM. The results also show that the suspended matter concentration decays exponentially with time, which is more obvious when the percentage of inorganic suspended matter accounting for total suspended matter is higher. When the suspended matter concentration is low, no clear relationship is found between settling velocity and suspended matter concentration. But settling velocity obviously rise with the increase of suspended matter concen- tration while the latter is high.