The Arc Slab Theory And Technology To Prevent And Treat Bump At Bridge-head On Soft Foundation

Bump at bridge-head is caused by differential settlement of the embankment fill. Itis a common problem in the operation of the road, especially serious on soft foundationroad. So far the disease mechanism and its control theory is not yet mature and nocompletely effective measures and methods have been found to solve this problem inengineering. This paper combines the typical characteristics of foundation soil ofZhongQi Yancheng automotive proving ground, then develop and put forward the newtype of bridge strap transition system, carried on the theory discussion and the finiteelement numerical analysis which is on the basis of the predecessors’ strap concept.This paper summaries the present research condition of the slab at home andabroad and the methods of dealing with bump at bridge-head on general; Then discussesthe different types transition system of new bridge slaps and it’s rationality andfeasibility.This paper establish fine finite element analysis models by the large softwareABAQUS to analyze the two-dimensional abutment foundation model onpost-construction consolidation settlement. This paper analyzes and comparespost-construction settlement condition of three soft abutment foundation models: noslabs, rectangular slabs with corbel, arc slabs with corbel. As to arc slaps with corbel, bychanging the length of slabs, embedment depth, thickness of the slabs, and supportingways at the bottom of the far-end-slab to analyze the different factors to control theeffect an influence of the bridge foundation uneven settlement. The research shows thatcurved slabs have more advantages than conventional rectangular slabs, as it canachieve very good at half-rigid transition on bridge foundation, and it can avoidreoccurring bump at bridge-head of conventional rectangular slaps. By using ABAQUS this paper respectively establishes three-dimensional finiteelement models of rectangular slabs dynamics calculation and arc slabs dynamicscalculation. This paper analyzes different influences on the dynamic response of a slababutment by comparing difference of speed, tire pressure, the influence of dampingratio under single vehicle load; analyzes the most unfavorable unit of principal stress ofslabs load and the dynamic response of the vertical displacement of corbel undermultiple vehicle loads; analyzes and contrast the dynamic response between therectangular slab models and arc slab models before and after padding void at the bottomof the slaps by using ABAQUS/Explicit.This analysis shows that: under the same condition, the slower the speed is, thegreater the tire pressure is, the lower the damping ratio is, the greater the principaltensile stress of the most unfavorable position unit of the straps is; under the samecondition, the principal tensile stress of the arc slab models is much smaller thanrectangular slab model; among three factors, the tire pressure and speed have themaximum impact, damping ratio has the minimum impact; plastic deformation on slabsdoesn’t occur under multiple vehicle loads, but irreversible plastic deformation occurson foundation soil at the bottom of corbel; After the padding void at the bottom of theslaps, the principal tensile stress of slabs increase obviously.