三角洲分流河道与朵叶体形成过程的物理模拟

Physical Simulation of Delta Distributary Channel and the Formation Process of Leaf Body

利用水槽实验对三角洲分流河道与朵叶体的发育过程进行模拟,以期认识其形成特点。研究发现,实验过程中砂体的长宽比先减小后增大,并且由于砂体厚度从正前方往两侧逐渐减小,而且不同位置处的水流条件和泥沙供应的不同,从而导致了朵叶体发育机制不同。在整个实验过程中,朵叶体和片流是交互出现的。河道的类型主要分为4种,分别是顺直型、微弯型、分叉型、交汇型,其中交汇型还可分为Ⅰ型和Ⅱ型。顺直型河道在砂体发育的各个时期均有发育,微弯型河道主要出现在砂体发育的中期和末期,而分叉型和交汇型两种河道则主要出现在砂体发育的末期。

In this paper,the development process of distributary channel and leaf body of delta is simulated by flume experiment,in order to further understand its forming characteristics. The study found that the length and width of the experimental process of sand ratio decreases first and then increases,and the thickness of sand body from the front side to decrease gradually,but at different locations and different flow conditions of sediment supply,which led to the growth mechanism of different lobes. During the whole experiment,the leaf body and the slice flow appeared interactively. The types of river channel are mainly divided into four types： straight type,micro bend type,bifurcation type and intersection type. The straight channel is developed at various stages of sand body development,and the micro bend channel mainly occurs in the middle and late stages of sand body development,while the two types of bifurcation and confluence mainly occur at the end of sand body development.