Hydrodynamic depositional numerical simulation and its implication for shallow-water braided river deltas
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摘要:
为了深入研究远源型浅水辫状河三角洲发育过程和沉积模式，基于现代沉积水动力条件，设计水动力数值模拟的初始模型和边界条件，再现远源型浅水辫状河三角洲的发育过程，分析沉积厚度和水流流速特征，对比分析沉积正演模拟结果和现代沉积实例，讨论不同级次的分支河道对浅水辫状河三角洲朵叶增生的控制作用，总结基于分支河道分级的远源型浅水辫状河三角洲沉积模式。结果表明：1）一个完整的洪水-间洪周期内，废弃的一级分支河道、次级分支河道和朵叶体是三角洲沉积厚度增加的主要场所；2）与次级分支河道相比，一级分支河道具有“流速快、废弃慢、数量少、延伸长、改道频繁、下切程度高、内部沉积慢、废弃沉积厚”的特点，一级分支河道的洪水期改道方向控制朵叶体的发育位置和方向，次级分支河道数量和延伸距离影响着朵叶体的增生规模；3）温暖潮湿的气候条件下洪水期水动力较强，易形成大规模的平面连通、纵向切叠的带状分支河道-朵叶增生体复合砂体；干旱气候条件下
Abstract:In order to deeply study the development process and sedimentary model of the distal shallow-water braided river delta, based on the modern sedimentary hydrodynamic conditions, the initial model and boundary conditions of the hydrodynamic depositional numerical simulation were designed. The sedimentary process of the distal shallow-water braided river delta was numerically simulated. The characteristics of the sedimentary thickness and flow velocity were analyzed. The results of the hydrodynamic depositional numerical simulation and the modern sedimentary examples were compared and analyzed. The controlling effect of distributary channels of different levels on the proliferation of shallow-water braided river delta. The sedimentary model based on the classification of distributary channel were summarized. The results show that: 1) in a complete flood-interflood
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