Scour and scour countermeasures at bridge sites     

Yee-Meng Chiew 《天津大学学报(英文版)》2008,14(4):289-295

This paper examines scour and scour countermeasures at bridge piers and abutments. Abutment scour is by far more complex than its counterpart associated with piers because of the possibility of the presence of a floodplain. Notwithstanding this, the mechanism of scour at both piers and abutments is very similar; moreover, the failure mechanisms associated with both armoring and flow-altering countermeasures are not very different. In rivers with a floodplain, abutment scour becomes much more complex. In cases where the abutment ends at or near to the floodplain, it can initiate bank erosion, which clearly is an important erosion problem that is quite distinct from the customary scour at either an abutment in rivers without a floodplain or a pier. For this reason, abutment scour can be very site-specific while pier-scour is more generic in nature. To this end, the ability to identify the type of abutment scour that may form in a particular channel is closely related to an engineer＇s ability to propose devices for effective scour countermeasure.By summarizing research efforts on using riprap as a pier or abutment countermeasure over the past few decades, this paper highlights the deficiencies of riprap in arresting pier scour. To this end, different failure mechanisms are identified. They are shear failure, winnowing failure, edge failure, bedform-induced failure and bed-degradation induced failure. Each failure mechanism can singly or, more likely, combine to cause the eventual breakdown of the riprap layer. The study shows that a riprap layer is vulnerable to other failure mechanisms even though it is adequately designed against shear failure, rendering it ineffective in arresting scour.  相似文献   

钱塘江河口尖山河段的围涂治理     

李来武  杨火其  王文杰  鲁海燕 《科技通报》2015,(7)

对钱塘江河口尖山河段河道主槽不稳,摆动频繁的原因进行了分析。针对该河段地形地貌、水动力条件和泥沙特性,采取了抛筑长丁坝结合围涂进行河道治理的方法。通过余姚岸段抛筑方案的比选研究,分析了抛筑长丁坝对钱塘江涌潮的影响,抛筑顺序对促淤效果的影响。采用水槽试验手段,确定了砂肋软体排护底施工所需要的最小船抛压载厚度。工程实施后,贴岸南股深槽推移到了主槽区,岸线前沿高程普遍抬高,形成了沿岸滩涂,提高了堤防的安全度。  相似文献   

试论水库除险加固中的设计误区     

王志强  张瑞娟  张乃菊  解学相  杜永春 《科技成果管理与研究》2010,(7):91-93

文章针对近几年水库加固的实际施工技术方案,结合施工和管理实际,对设计施工中的问题进行了分析总结,指出了水库除险加固中的安全误区,水库设计应服从于安全、但安全和效益两个角度同等重要!  相似文献