长江中下游航道整治护滩带损毁机理分析及应对措施

Failure mechanism and relevant measures for beach protection band in lower-middle reaches of Yangtze River

护滩带是长江中下游航道整治工程中的主要护滩结构型式,在工程应用中,常出现塌陷、悬挂、架空和鼓包等破坏,减弱了护滩效果.通过对护滩带损毁过程的试验观测、损毁影响因素分析、护滩带块体间脉动力及受力分析,研究了护滩带常见的边缘塌陷、悬挂、排体中部鼓包或塌陷等破坏类型的损毁机理.结果表明:流速是护滩带破坏的动力因素,局部冲刷坑的形成与发展是护滩带破坏的诱发原因,编织布、系结条及接缝部位的抗拉强度不够是护滩带破坏的直接原因.并提出在护滩带边缘抛四面六边透水框架、增大排体自身的抗拉强度、选择合理的平面布置型式等应对措施,研究成果对护滩建筑物设计具有一定参考价值.

Beach protection band is the main structure type of channel maintenance engineering in the lower-middle reaches of the Yangtze River.The effects are weakened due to structure collapse,hanging,overheading,bulging,etc.Through the test observation of failure process,the damage factors,fluctuating force,and stress,the failure mechanism of common types,such as edge collapse,hanging,bulging and middle collapse,are analyzed.The results show that the magnitude of flow velocity is the dynamic factor of destruction,the formation and expansion of local scour holes are the inducing elements,and the insufficient tensile intensity of fabric,tied rope and joint position is a direct factor.Some countermeasures are also presented,such as setting permeable frames of tetrahedron with six sides at the edge of band,strengthening the structure′s tensile intensity,and selecting reasonable types of layout,etc.The research results can be used as a reference for the design of similar beach protection structures.