Time Variation of Scour at Abutments
Time Variation of Scour at Abutments
复制标题
桥台冲刷的时间变化
DOI：
10.1061/(asce)0733-9429(2005)131:1(11
复制
发表时间：
2005
影响因子：
2.4
通讯作者：
A. K. Barbhuiya
中科院分区：
文献类型：
--
作者：
S. Dey;A. K. Barbhuiya
提出了一个半经验模型来计算清水冲刷条件下均匀和不均匀沉积物中短桥台（桥台长度/水流深度1）（即垂直壁、45°翼壁和半圆形）的演变冲刷孔冲刷深度的时间变化。计算冲刷深度随时间变化的方法是基于泥沙质量守恒的概念，考虑主涡系统作为冲刷的主要媒介，并假设逐层冲刷过程。对于平衡冲刷孔，通过物理推理和量纲分析，确定影响无量纲平衡冲刷深度（冲刷深度/台肩长度）的特征参数为超台肩弗劳德数、水深-台肩长度比、台肩长度-泥沙直径比。在有限的清水冲刷条件下（接近河床沉积物的临界流速），对均匀和非均匀沉积物中不同尺寸的垂直墙、45°翼墙和半圆形桥台的时间变化和平衡冲刷深度进行了实验。本模型与从本实验获得并由不同研究者报告的均匀和不均匀沉积物中冲刷深度随时间变化的数据密切对应。
A semiempirical model is presented to compute the time variation of scour depth in an evolving scour hole at short abutments (abutment length/flow depth 1), namely the vertical wall, 45° wing wall, and semicircular, in uniform and nonuniform sediments under a clear water scour condition. The methodology developed for computing the time variation of scour depth is based on the concept of the conservation of the mass of sediment, considering the primary vortex system as the main agent of scouring, and assuming a layer-by-layer scouring process. For an equilibrium scour hole, the characteristic parameters affecting the nondimensional equilibrium scour depth (scour depth/abutment length), identified based on the physical reasoning and dimensional analysis, are excess abutment Froude number, flow depth—abutment length ratio, and abutment length—sediment diameter ratio. Experiments were conducted for time variation and equi- librium scour depths at different sizes of vertical walls, 45° wing walls and semicircular abutments in uniform and nonuniform sediments under limiting clear water scour conditions (approaching flow velocity nearly equal to the critical velocity for bed sediments ). The present model corresponds closely with the data of time variation of scour depth in uniform and nonuniform sediments obtained from the present experiments and reported by different investigators.