Model Test And Numerical Simulation Of Optimization Of Gravel Pile Composite Foundation

Vehicle bumping at bridge head is one of the key problems to be solved in the bridge construction of soft soil foundation,solving the vehicle bumping at bridge head is largely to determine the foundation treatment scheme.Low strength concrete pile composite foundation was often used to deal with soft soil subgrade,and reduced the settlement difference between a bridge and embankment by changing the pile length,but how to determine the pile length,and prevent the second vehicle bumping between the treated and untreated area of the highway has not been solved.On the basis of summarizing the revant research results,with the low strength concrete pile foundation treatment scheme adopted in the Jialichen Bridge,this paper analysed the pile length changes on eliminating the first and second vehicle bumpings by using the finite element method.Topology optimization method was introduced into the design of pile length optimization,and the optimal pile layout was determined to satify the needs of the first and second vehicle bumpings.Analysis shows that using isometric pile project low strength concrete pile on delaying vehicle bumping is obvious,but at the same time it leads to the vehicle bumping between the treated and untreated area of the highway.After the topology optimization,unequal length pile can not only reduce the phenomenon of vehicle bumping,but also can make the subgrade between the treated and untreated transition more smoothly and avoid second vehicle bumping.The result shows that the topology optimization is an effective method to calculate the pile layout of vehicle bumping,which can provide a effective method for the determination of the variable length of pile,and can greatly save the cost of construction projects.