STUDY ON DISASTER PREVENTION PERFORMACE IMPROVEMENT OF RIVER BANK PROTECTION WHICH DEVERTED RETAINING WALL CONSTRUCTION METHOD

Abstract

 In this study, in order to improve the disaster prevention performance of the Ganlock bank protection which made practical use of the retaining wall construction method as the river bank protection method, the roughness coefficient of the new Ganlock bank protection which improved the old Ganlock bank protection, the stable estimation against the hydrodynamic force, the characteristics of the flow velocity distribution and the inner flow structure were examined by the hydraulic model experiment and the dynamic model. As a result, it was revealed that the Manning’s roughness coefficient of the new Ganlock bank protection is 0.041, which is larger than that of the old Ganlock bank protection. From the calculation of the dynamical model, the critical velocity for drag and lift was calculated. In the vicinity of the new Ganlock bank protection, a large scale secondary flow was formed as compared with the old Ganlock bank protection, and the effect of reducing the primary mean velocity around the bank protection was recognized. Furthermore, a large and characteristic streameise vorical structure was formed around the new Ganlock bank protection and it was inferred that it contributes to the reduction of the primarry mean velocity and the generation of the secondary flow.