Research On Bearing Erformance And Grouting Reinforcement Technology Of Existing Bridge Pile Foundation

At present,after 20 years of operation,part of the bridges on national trunk line,the upper structure bearing capacity of which is so insufficient and serious damaged that it cannot meet the increasing traffic demand any more,while due to protect of the soil and other environmental factors,the characteristics of lower part of the bridge structure still continue to meet or take measures to meet the lower part of the structure needs of the new bridge.According to the actual engineering situation of the bridge,and considering the economic factors,in the bridge reconstruction,it is very useful to take down the upper load-bearing structure and use of existing bridge pile foundation.Such as a 20 m T bridge with a 9+2*0.5m wide,using of existing bridge pile foundation can save about 40% of the project cost,it has great economic value and practical value to study the existing bridge pile foundation bearing performance and reuse technology.The main contents of the paper are as follows:(1)Extensivly research related literature and information,study the value of using existing bridge pile foundation,to the effect of vehicle load on bearing capacity and deformation characteristics of existing bridge foundation,the influence of vehicle load on the bearing capacity and deformation of the pile foundation are summarized.;(2)Study on the interaction theory between the pile foundation and the soil body under the vehicle load based on the standardize the existing pile foundation design,summarizes the theoretical calculation method of vertical pile bearing capacity,horizontal force and the horizontal displacement;(3)On the basis of the standard issued by the Ministry of communications of bored pile,analyze the bearing capacity of pile,horizontal displacement and stress,settlement situation under different pile side soil conditions and different loading conditions.Firstly explore the pile-soil interaction rules through theoretical calculation method,establish a three dimensional stress model by finite element software Abaqus,analyze vertical pile bearing capacity,horizontal displacement and stress,settlement situation under the same condition,finally compare the calculated results and the numerical analysis results to verify the correction of finite element calculation;(4)Based on the construction detects of a bridge in Hebei Province,study the bridge pile testing data,analyze the interaction of pile and soil,and through the finite element software Abaqus to design the reinforcement way by pile bottom grouting for the existing bridge pile foundation,analyze the pile end reaction force and the pile settlement calculation results of the existing bridge pile foundation,and it has a good improvement compared with the test results,thus verify the validity of pile bottom grouting reinforcement measures.(5)Set the reconstruction of bridges in Hebei province as the background,analyze the content of the reuse of existing bridge pile foundations,and combined with the content of bridge pile foundation reinforcement design of the fourth chapter,study on the design theory and construction technology of pile foundation pile bottom grouting reinforcement.