| As the pit of high-rise building is deep and wide, pile with a huge capacity and the special properties of resisting the complex load becomes an ideal foundation forms. In the excavation process, the soil unloading causes movement of stratum and uplift of the bottom soil, leading to floating destroy and deviation of engineering piles on bottom. Based on this background, the influence of the pit excavation on bottom pile is analyzed in this paper.Firstly, the thesis represents a review of the domestic and foreign study on the theoretical analysis, experiment means and computing methods for passive piles, and the current status of study on the impact of pit excavation to buildings and pipes surrounding is also discussedSecondly, the mechanism of stratum movement and pile deformation under excavation process is analyzed Then pile-soil interaction is discussed from the perspective of soil arching effect, and the formation process of soil arching is discussed. In virtue of the finite element method, the mechanism of soil arching effect in clay soil and non-clay soil between passive piles are studied respectively, and the influence of the soil parameters, such as shear angle, Poisson's ratio, pile-soil contacting characteristics is analyzed. Meanwhile,In addition, the finite difference software FLAC3D is introduced with its operation principles and calculation flow, also the pile element needed in the numerical simulation of this paper is learned.Finally, with a analysis model based on a engineering example according to the influencing factors mentioned above, regarded FLAC3D as the development platform for secondary development, utilized embedded FISH language included in software, a 3D pit Excavation Construction is simulated, Moreover impact of friction,cohesion, length and radius of pile, construction methods on pile foundation have been studied at last in the thesis., Some conclusions have been educed which may guide practical project. |
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