The Analysis Of Soil Arching Effect Of Pile-supported Embankment By Particle Flow Code

Pile-supported embankments are referred to a type of ground treatment which uses rigid pile to consolidate the soft soil. It has many advantages such as short period of construction, small subsidence after completion and the lower cost and so on. During the filling process of pile-supported embankments, due to the relative displacement between pile and soil, filling particles rearrangement and wedge with each other, results in forming soil arch to transfer load the top of pile. The macro and micro mechanism in pile-supported (reinforced) embankment are researched by using method of combining indoor model test with particle flow numerical simulation test on the basis of previous studies in this article.The main research contents are as follows:First, based on visual model test of small scale indoor test of pile-supported embankment, this paper researches the change law of stress and displacement in the filling process, and observes grain displacement in soil arch region and reinforced soil interface. It also researches the influence of load transfer and effects parameters of soil arch due to the factors including height of fill soil, pile distance, size of pile-cap, differential settlement in pile soil and soon and analysis change law of micromechanics parameters of pile-supported embankment under the dynamic load.Second, applying microscopic photo analysis technology studies the particle motion and the evolution process of medial arch of the arch foot. It analyzes load transfer mechanism of pile supported embankment from the angle of particle size and reveals the mechanism of formation and development of soil arching effects.Thirdly, this paper selects two groups of typical working conditions to analyze the time effect between reinforced and unreinforced embankment under the load path of static load to dynamic load and then to static load. The response regularity of the pile and soil stress changing with soil particles rearrangement is discussed.Fourth, based on indoor tests, it establishes numerical model of discontinuous contact interface and the interactions of pile, soil and reinforcements in pile-supported reinforced embankment. It analyzes the connections between microscopic parameters and macroscopic mechanical behaviors such as soil displacement and stress field during the process of filling and loading. Combining with model test and changing micro-parameter, pile distance, size of pile-cap and etc of sand-soil, it researches effects of various design parameters on the properties of pile-supported embankment, and analyzes parameter sensitivity for further study in the mechanism of information and development of soil arch.At last, this paper builds discrete and continuous coupling numerical analysis model of pile-supported embankment widening engineering, and verifies its effectiveness.