Field Test Of Single Pile And Analysis Of Influence Of Pile End Sediment On The Bearing Capacity Of Single Pile

In the actual construction process of pile foundation,there are many uncertain factors leading to the instability of pile foundation quality.The bearing behavior of single pile is a very important index for evaluating the quality of pile foundation.It is found that besides the material properties and geometric dimensions of the pile itself,the lower stiffness of the bearing layer at the end of the pile(including compressible soft soil,construction mud,thicker sediment,sedimentation,etc.)can also reduce the resistance at the end of the pile,and significantly reduce the exertion of the resistance at the side of the pile,thus affecting the bearing capacity of the pile.Taking a project in Tianjin as an example,according to the field test results of test piles and engineering piles,starting with the theoretical knowledge of bearing behavior of single pile,this paper analyses the law of load transfer of single pile and the causes of insufficient bearing capacity of single pile.At the same time,FLAC 3D finite difference program is used to simulate different sediment thickness and analyze the influence of pile end sediment thickness on the bearing behavior of single pile.The main contents of this paper are as follows:1.Calculate the bearing capacity of a single pile according to the code,and analyze the influence of pile end sediment on the bearing behavior and settlement of a single pile.2.Combining with the project of Baodi District in Tianjin,the scheme of test piles and engineering piles is determined.According to the test results,the bearing capacity and settlement characteristics of single pile of test piles and engineering piles are analyzed respectively.The reason that affects the bearing capacity of single pile of engineering piles is preliminarily determined to be the excessive thickness of sediment at the end of piles.3.Using FLAC 3D finite difference program to simulate the pile bottom sediment thickness of 0 mm,50 mm,100 mm,200 mm,300 mm and 500 mm respectively,to explore the causes of insufficient bearing capacity and excessive settlement of single pile,to summarize the influence of the pile end sediment thickness on the bearing behavior of single pile,and to provide reference for similar pile foundation design and construction.