关于沉沙池计算中的水流挟沙力

一度流超饱和输沙法是考虑了超饱和输沙特点的泥沙沉降计算方法．沉沙池内水流挟沙力是一定水力和床沙组成条件下水流挟带床沙质的能力．从已建沉沙池沉降标准、池内设计水流水力以及床沙组成条件来看，沉沙池运行前期、中期水流挟沙力一般都很小．用一度流趋饱和输沙法计算沉沙池沉降率时可不考虑水流换沙力的影响．均匀流条件下，用不考虑挟沙力和考虑挟沙力的一度流超饱和输沙法分别计算沉沙池的沉降率，二者相对误差取决于挟沙力与进口含沙量之比，该比值小于0．2时，相对误差小于20％．沉沙池内挟沙力与进口含沙量之比小于0.2时，用一度流趋饱和输沙法计算沉沙池的沉降率，可不考虑水流挟沙力的影响．

Flow Silt Carrying Capacity Concerning the Calculation of Desilting Basin

The sediment transport method of one-dimensional flow super-saturation is a silt settlement calculating way of taking the characteristic of super-saturation sediment transport into account. The flow siltcarrying capacity of desilting basin is the capacity of flow carrying bed silt under given component conditionbetween water power and bed silt. Judged by the settlement standard,inner water power of design flow and bedsilt component condition of already built desilting basin, the flow silt carrying capacity is very small during theearlier and middle period of operation. Under the condition of uniform flow, the relative error of settlementrate, which is counted respectively by this way of thinking over and not thinking over the silt carrying capacity,depends on the ratio of silt carrying capacity and inlet sediment concentration; when this ratio is less than 0. 2,the relative error is less than 20%. So, under the condition of the ratio of silt carrying capacity and inletsediment concentration is less than 0. 2,and when we calculate the settlement rate of desilting basin with thesediment transport method of one-dimensional flow super-saturation, the influence of flow silt carrying capacitycan not be considered.