Erosion On The Impact Of The Pier Security

Scour is one of main factors causing damage to the bridge piers. The bridges builded in the early years generally use gravity pier and shallow spread foundation in China, and these type bridge piers would be affected by scour more seriously. So, research about the effect of scour on the piers' safety and stability has important engineering significance.Based on the transversely isotropic elastic half-space foundation model and the underwater detection of scour, the effect of scour on the piers' safety and stability was studied by consideration the various of scour and foundation parameter in this paper. Additionally, numerical simulation of the influence of scour on piers' stability was carried out by finite element method. Finally, all kinds of scour protection measures and their advantages and disadvantages, which provided reference for the piers' treatment, were studied on the basis of the research of pier's local scour mechanics.The results showed that the grain diameter and approach velocity of flow had obvious relations with local scour depth, and the influence curve showed that it made much more influence to the local scour depth when the grain diameter was small and approach velocity of flow was high. Underwater detecting indicated that all the piers had suffered different scour damage, and the 4 pier was the most seriously. There were clear relationships between scour area of the foundation base and the piers' check items, the flexibility horizontal displacement of pier's top and the eccentric distance, compared with other check items, firstly reached the maximum permissible value when a less scour happened, and the limit washed area percentage of total area of the foundation was less than 20, which was similar to the conclusion of numerical simulation by FEM. The theory and practice of scour protection is developing all the way, and all kinds of protection measures have their characteristic and applicability respectively, which should be adopted depending on flow condition, riverbed condition and result of underwater detecting.