Comprehensive Evaluation Of Mountain Road Bridges And Culverts Damaged Mechanism Of Its Anti-flood Capacity

Bridge and culvert that is one of the main facilities of highway drainage is very important in drainage system. In washout by flood of Mountain Road, washout by flood of Bridge and culvert occupies the very big proportion and damage patterns are also various. Therefore, it is very necessary for evaluation and forecast the anti-flood capacity of Bridge and culvert to study washout by flood mechanism of Bridge and culvert and put forward anti-flood combined capacity index of Bridge and culvert.On the base of analyzing the flow form of Bridge and culvert and doing the hydraulic model test, the paper studied the velocity distribution of Bridge and culvert and the change character of hydraulic line, and researched different forms of inlet and outlet, the aperture, the length, the flow capacity of Bridge and culvert to influence the velocity distribution of Bridge and culvert and the hydraulic line. The paper provided incidence formula of scour depth and influencing factor, and pointed out that the main factor about influencing scour depth was hydraulic elements and soil condition of riverbed.According to influencing factors and dissipation energy mechanism of the forming partial erosion hole, it studies to the process pitching reinforcement and dissipation energy test for Bridge and culvert, and draws a conclusion: increasing the length of pitching, it can reduce the partial scour depth at the back of Bridge and culvert; in the same flow capacity, adopting wing wall as outlet or inlet, the partial scour depth is less than that of end wall; adopting deflecting as a dissipation energy manner, it can get a good effect and reduce the partial scour depth, but if it is the form of end wall, the dissipation energy effect of deflecting is not well; adopting riprap protection, it can get the scour balance in a short time and receive a best effect, at the same time, the scour depth can reduce greatly.The paper brought forward to the protection and reinforcement measures of Bridge and culvert for Mountain Road on the base of the partial erosion of Bridge and culvert, dissipation energy test and the relative field investigation.According to the result of field investigation and relative laboratory experiment data, the paper brought forward disaster index of the hazard bearing-body and anti-disaster comprehensive evaluation index, which provides exact decision-making to program, design, construct and cure for Mountain Road.