Analysis Of The Causes Of Bridge Pile Foundation Defects During Construction And Research On Reinforcement Schemes

By the end of 2020,there are more than 1 million bridges in China,and correspondingly,the usage of pile foundation is also huge,so the technical problems brought by pile foundation construction have attracted people's attention.Facing the defects of pile foundation caused by technical problems,how to reinforce scientifically and reasonably can not only save the construction investment,but also delay the construction period,which is very important.Based on the bridge pile foundation under construction,this paper analyzes the causes of pile foundation defects and puts forward targeted reinforcement schemes.Study the technical indexes of different reinforcement schemes,compare the economy of the reinforcement schemes,verify the feasibility of the reinforcement schemes,and carry out exploratory simulation on the reinforcement schemes.The following conclusions are drawn:(1)Based on the geological conditions and the test results of pile foundation,it is analyzed that the defects of pile foundation are due to the fact that pile foundation is in V-shaped terrain,and the construction is in rainy season,with heavy wind and rain,and rainwater flows into the pile hole,which leads to the decrease of the strength of slurry retaining wall and the falling off of retaining wall during pouring,which leads to the phenomenon of excessive sediment at the bottom of pile.(2)Modeling and analyzing the defective pile foundation,comparing and analyzing the technical indexes of the complete pile foundation and the defective pile foundation,it is concluded that the settlement,vertical bearing capacity and horizontal bearing capacity of the defective pile foundation can't meet the technical indexes of the pile foundation,and it can't be used any more,so it needs to be reinforced.(3)According to the defective parts and types of pile foundation,formulate targeted reinforcement schemes,and evaluate each reinforcement scheme from the technical and economic point of view.It is concluded that the high-pressure grouting scheme has the best economy and the small-diameter steel pipe pile reinforcement scheme has the highest technical index.Based on the comprehensive site construction conditions,it is preliminarily concluded that the defective pile foundation is reinforced by small-diameter steel pipe pile.(4)After the implementation of the reinforcement scheme,it is found that the reinforcement effect of the defective pile foundation is good through detection.Because the defect degree of the pile foundation is not great,the finite element software is used to discuss the reinforcement effect of steel pipe piles with different lengths,and it is concluded that when the length of steel pipe piles is equal to 1/10 of the pile foundation,it not only meets the technical requirements of the pile foundation,but also achieves the effect of high economy.