中文摘要：

采用非均匀沙进行水槽概化试验，研究水流泥沙从山区进入窄浅水域过程中三角洲堆积体的形成规律。经过425h试验历时，总结如下规律，整体：堆积体先纵向推进，再垂向淤积抬高，最后横向展宽；纵向：初始历时内（Oh-266h），堆积体表面以顺直和分汉河槽为主且以30h左右试验历时为周期交替出现，堆积体的前缘部分先随顺直河槽在河床中间左右摆动中进行纵向推进，待其淤积厚度与所在水深的比值达到0．8左右，纵向推进停止，引起河槽上段向两侧以分汉形式挟沙进行纵、横向输移。266h-425h内，随堆积体流程变长，纵向坡降变大，河床表面以微弯河槽为主，堆积体的前缘部分随河槽主流摆动进行纵、横向输移；堆积体的纵向推进速率随历时增加逐渐减小，最终以0．05m／h左右速率稳定推进；垂向：上段整体均匀淤积抬高，中、下段随河槽摆动在河床左侧、右侧和中间区域周期淤积抬高；堆积体的垂向抬高速率随历时增加逐渐减小，并以0．027cm／h左右速率淤积抬高；横向：随前缘体推进停止，水沙流在上段左右两侧以分流口形式，先垂直边壁方向、后在侧蚀作用下斜向边壁沿不同河槽方向进行横向展宽发展。

英文摘要：

This study conducted a generalized experiment of non-uniform sediment to examine the formation pattern of delta deposition in shallow and narrow water basins caused by water and sediment flow from the mountains. A test of 425 hours long is presented in this paper and its results are summarized as follows. In overall, the depositing body advances longitudinally first, then silts up gradually, and finally expand transversly. At the stage of initial 266 hours, straight and branching channels appear alternately on the body surface with a switch period of 30 hours, and the depositing body advances roughly along the stright channel but its front takes a swinging manner. This continues until the thickness-depth ratio reaches 0.8, and then the upper channel starts flowing transversely in branching forms, carrying sediment to the side regions of the channel. At the stage afterward, longitudinal bed gradient becomes greater as the depositing zone has expanded quite long. On the bed a slightly curved channel has formed and the front maintains its swing motion that is energized by the swing mainstream of the channel. The longitudinally advancing rate is decreasing with time until eventually appraoching a steady value of roughly 0.05m/h. As for bed elevation change, in the upper section the deposited sediment is spreaded uniformly over the bed; in the middle and lower sections the depositing takes a periodical way as a result of main channel swing between the left and right sides. The bed rising rate is decreasing with time until becoming steady at a rate of about 0.027cm/h. As for tranverse spreading in the upper section, after the deposition front stoped advancing the water and sediment flow starts spreading tranversely in the form of cave mouths on the left and right sides, first in the direction normal to the side walls and then along different channel directions under the action of erosion.