Research On The Influence Of Pile-column Pier Stability Under Riverbed Undercutting

As an important part of the transportation of the bridge,since ancient times has been widely used,has a long history,especially in recent years the rapid development of the national economy as well as science and technology,various bridge types and structures can be seen everywhere,has created tremendous social and economic benefits to the country.With the construction of the bridge,along with the rapid development of contemporary bridge technology,the calculation theory and method of various types of bridge structure are maturing,but in recent years,due to the interference of the natural evolution of the pier,river water flow and sediment and the excessive extraction of sand humans have accelerated the development speed of riverbed cut,the exposed part of the pile the interaction between pile and soil,reduce the relative increase of the length of bridge pier,pier flexible deformation leads to increased crack on deck,and the general design of the bridge service life is very long,the stability of the bridge,the safety is seriously affected.Because of the column piers in practical engineering especially is widely adopted in the mountainous area large terrain elevation,and the on column piers of piles combined analysis are few,mostly to the two separately were analyzed,and the engineering practice is not consistent.Based on the pile column bridge as a whole to study,to explore the influence of riverbed cut pile column bridge stability.The pier top horizontal displacement calculation is an important indicator of pier stability,reliability and durability of development in the pier top level,to establish the finite element model of pile column pier by :Midas civil,introduces the calculation method of the pile-soil interaction theory and the classical method,choose to add in the pile elastic joints connect to simulate the pile in the "m" method under the stress condition,and in the same load,the construction in different depth under the riverbed cut pier simulation analysis of horizontal displacement of the top single pier model with different diameters of the diameter of the pile pier,by analyzing the different parameters of the model results,obtained the same riverbed cut depth is more harmful for large flexible pier,with a pier under different cutting depth under the lateral displacement of pier was larger than on a level.In the structure of the two kinds of research methods and theoretical analysis of loss of stability critical load in Hubei,a practical engineering and finite element model of the whole bridge is established to analyze the stability of using beam element,the grillage method is used to simulate the bridge superstructure,substructure is through the connection to simulate the interaction between pile and soil added the use of :Midas node elasticity,load tracking,the moving load equivalent static load of the bridge into the bridge under operation condition simulation,through the bridge control under different cutting depth model after the buckling mode and the calculated stability coefficient and the pier pier top horizontal displacement of each model results summary concluded that the reaction under the riverbed cut on the degree of influence of pile column pier stability.