Interface Analysis Of 3d Rock-socketed Pile

Rock socketed piles are widely used in high-rise buildings,large bridges,heavy buildings and other projects,There are a lot of researches about its working mechanism and many kinds of failure modes.For example:Failure modes such as Shear and compression failure,overall shear failure,and failure of rock interface in Pile end and so on.The theoretical model of the application is different,and different results are obtained.In this paper,it is assumed that the pile body and rock have enough strength,The failure of rock socketed piles is Interfacial failure and the working mechanism of rock socketed pile is studied by means of indoor model test.In order to make the test data can reflect the actual project,the process of model test simulated the pile forming process of actual engineering pile,The pile load,displacement and strain were separately measured with GH-200 electronic universal testing machine?WDW-E200 D load sensor?DH-3814-4 static strain tester and Dial indicator,The relationship between axial force and frictional resistance is obtained by using the mechanical formula.Two specimens were made for one time loading and repeated loading tests and conclusions are as follows:1)Through the one time loading test,finding that load-displacement curve can be divided into three stages: ?stage belongs to the elastic stage;?stage belongs to the yielding stage;? stage belongs to the residual deformation stage.These three stages show the relationship between the displacement of pile top,the displacement of pile bottom and the amount of compression between pile body and the loading value;2)In the process of loading and repeated loading,the axial force of the pile is gradually decreased from top to bottom,and there is some residual deformation after unloading;3)The friction resistance of the pile body is upper lower and end small when the load is applied to the limit load,that is,the interface friction of pile and soil is small,and the interface friction of pile and rock is large.The maximum value of frictional resistance at the interface between rock and soil;4)one time loading and repeated loading reflect a common problem: With the increase of the pile top load value,the force is gradually spread to the bottom of the pile,the frictional resistance at the cross section of the whole pile is not synchronous.The friction force between the pile and the soil is first applied to the best,then the friction force between the pile and the rock to the best,when the pile rock interface will be destroyed,the bearing capacity of the pile reaches the extreme value.