Researches On Bearing Mechanism And Deformation Of The Pile-supported Embankments Based On Soil Arch Effect

With the rapid development of highway and railway construction in our country, the construction process often encounter the problem of large area soft soil. Piled-supported embankment is an effective form of structure which is suitable for the type bad foundation, and also caused extensive attention from academe. However, the working mechanism of piled embankment and the stress-strain characteristics are very complex. When conducting the analysis of soil arch effect, The key problems, which is in need of analysis are pile-soil stress ratio, differential settlement between soil and pile, design method of Piled-supported embankment based on soil arching effect.According to the existing research, some different model of soil arch and the corresponding calculation methods has been proposed. However their study of soil arching mainly concentrate on the effect of different design parameters, and ignore the influence of differential settlement between soil and pile on soil arch effect. Cao Weiping, LIU Hanlong who verify the differential settlement between soil and pile are closely related to exerting degree of soil arch effect, conducting laboratory model experiments and Numerical Simulation Analysis. However, the theoretical research about pile-soil stress ratio and differential settlement between soil and pile are also deficient.In allusion to this situation, first,the article assumes the plane of equal settlement to determine the integrated degrees of soil arch effect. Second, Based on the differential settlement of piles and soil, soil arch effect and load distribution, the assumption that the volume of pile up into the embankment was equal to the volume of compression of the soil arch was put forward. By combining with the mechanical analysis of pile-supported embankment and the deformation equilibrium of piles and soil, the formula between the pile-soil stress ratio and the height of soil arch with differential settlement was derived. Finally, comparative model test and numerical analysis were performed to check the validity of this method and this new method was also used to generate a parametric study in order to investigate the effects of various parametric, such as replacement ratio, the height of embankment and friction angle of the soil on the behavior of the pile-soil stress ratio and the height of soil arch.To further verify the reasonableness of the theory, two-dimensional analytical model is established by numerical simulation software ABAQUS. The height of equal settlement section are acquired by analyzing stress-strain field of the model. The result is 1.4 times the clear distance between piles. This verify the assumption of the height of equal settlement section. Then, were change piled embankment design parameters, get embankment height and properties of filled earth, pile spacing on soil stress ratio of pile and pile-soil differential settlement. Then, the numerical model of stress-strain field varies with time history output can be obtained by differential settlement of pile-soil soil arching played extent.Finally, the design method of piled embankment is established, based on soil arching, adjusting the distance between piles and the size of pile cap, making embankment reach the corresponding performance requirement, expecting to guide engineering practice.