Project Performance Study Of Model Piles With Branches And Plates Under Repeated Load In Silty Clay

The pile with branches and plates is a new pile type of the recent 20 yeas which has a high bearing capacity, good solid embedded and more economical, therefore it is widely used because of these characteristics. Studies show that, bearing capacity of different bells of the pile with branches and plates can be doubled improved compared to equivalent diameter piles, but the increased use of concrete is very limited. Such as in this model test, the bearing capacity of the pile with branches and plates is 3 times the equivalent diameter piles, while the amount of concrete more than about 15%. So that the pile with branches and plates is a very substantial economic benefits.Much research has been done about the performance of compression strength of piles recently, while little is done about piles when under repeated load. So, characteristics of the pile with branches and plates, the construction process and research status are introduced in this paper. Through repeated loads when under loads of different size and different loading frequency, as well as the role of one-time load the pile with branches and plates model test, according to the model pile-top settlement and collected data measured in the bell-piles different locations paste strain gages planted in the soil and the pressure box, the load transfer mechanism and pressure changes in soil of bell piles was analyzed and compared. Finally, the finite element software Abquas numerical Simulation of the pile with branches and plates' engineering traits was done in different soil moisture content when under repeated load.When the pile with branches and plates in different load sizes and different loading repetition frequency, bearing capacity will be different and also there are large differences of settlement deformation .The working load size, loading and unloading frequency which affect the settlement are the main factors. Load transfer of bells is very remarkable because pile axial force in the bell location of the mutation occurred so that axial force significantly reduced under bells, pressure changes of soil around piles and up and down the bells are complex; especially the bells upper and lower soil pressure changes will appear wavy.By analysis of the numerical simulation of the same soil, three groups in different water content of the pile with branches and plates under repeated load, changes in soil moisture content of the bell-piles on the characters of the project were studied. Pointed out by the impact of water content, soil samples of silty clay void ratio, coefficient compressibility, modulus of compressibility, cohesion intercept and other indicators of physical and mechanical properties have changed resulting in project pile traits change. The greater the soil moisture content, the smaller the void ratio, the smaller the modulus of compressibility of soil, resulting in greater settlement deformation under the same load.