Impact Force of Debris Flow on Bridge Pier and Control

摘要

Bridge is commonly used to cross debris flow gully for mountain road construction.Impact force of large stone in debris flow acting on bridge pier is the key factor for bridge piers and protective structure design.From the perspective of energy conservation,using the Thornton elastoplastic contact criterion,considering the buffer action of debris flow fine particles and upper structure dynamic response properties of bridge pier,this paper deduced calculation formula of impact force of large stone in debris flow acting on bridge pier,avoided the cantilever or the simply supported beam structure load-carrying mode.Based on studying impact force of large stone acting on the Den Jigou bridge pier under different factors and comparing with previous research results,it is found that considering the buffer action of debris flow fine particles and dynamic response properties of upper bridge pier,the calculation results of impact force of large stone is lower than the calculation results of general elastoplastic theory under different speed and different radius of large stone.If the thickness of debris flow fine particles is 2.4 cm,the calculation result of impact force of large stone will be reduced by 21％.Impact force of large stone will be reduced by 1.4％ under action of inertia force of upper bridge pier.Using the low elasticity modulus and high decrement material in bridge pier protection will be conducive to large stone impact energy dissipation.