来沙系数对河道冲淤的影响研究

Study on the Influence of the Incoming Sediment Coefficient on the Scour and Sedimentation

来沙系数以S/Q表示,因为相同的流量流速可能不同,而流速是影响输沙能力的重要因素,所以来沙系数缺乏最基本的物理意义,是一个纯粹的经验指标;不少人认为黄河下游的临界来沙系数在0.012左右,没有考虑滩槽冲淤性质的差别和上下河段河型的不同;就黄河泥沙而言,含沙量越大,泥沙浓度在垂线上越均匀,越容易输送;黄河下游窄深河槽洪水期具有多来多排的输沙特性,在实测资料范围内不存在临界来沙系数;不受来沙系数的限制,利用洪水集中排沙是解决黄河下游泥沙淤积最现实的途径。

Incoming sediment coefficient is represented by S / Q , since the same flows differ in velocity , so the incoming sediment coefficient is a purely experiential index which has no basic physical significance;many consider that the critical incoming sediment coefficient at the downstream ofthe Yellow River is about 0.012 , which however takes no differences in natures of erosion and deposition and types of downstream and upstream of the river into consideration;with regard to the sediment of the Yellow River , the more the sediment is , the more even the sediment thickness along the vertical line and the easier it is conveyed;the flood period of narrow and deep riverbed at the downstream of the Yellow River is characterized of more flood and more flushing , which has no critical incoming sediment coefficient available;to make use of floods for concentrated sediment flushing is considered an important way to deal with sediment accumulation at the downstream of the Yellow River.