Reasearch On Micropiles To Earthquake Load

Micropile is a type of small diameter drilling pile constructed by strong reinforcement and pressure guouting with pile diameter between70and300mm and big slenderness ratio. With its ductility, flexible, and the ability of resisting the additional force,micropile plays a huge advantage during the construction of earthquake.However,the theory of design calculations still lags behind engineering practice,so it’s a more necessitous and cutting-edge task. In this paper, on the basis of previous studies, studiing the dynamic response characteristics of the slope body and micropile by using the finite element software PLAXIS dynamic analysis moduleUsing numerical analysis method, regard the soil as elastic body and elastic-plastic body respectively, research in earthquake under the action of micropile, the internal force change of the micropile and the slope deformation and the change of seismic acceleration amplification factor. Studies show that regard the soil as elastic-plastic body, the internal force of micropile and the relative displacement of slope and the earthquake acceleration amplification factor are bigger.On the seismic response of the micropile under the different pile arrangement, the main research consider that in earthquake, the internal force change of the micropile and the slope deformation and the change of seismic acceleration amplification factor in different ways of connection between the top of the (fixed edge connection and hinged connection) and different constraints of the bottom of the pile (embedded general soil layer and hard rock), and different slope Angle (0°、5°、10°、10°and20°) arrangement of micropile group under the condition of the same seismic wave input force in the body. Results show that when the top of piles and pile caps is solid connection, the bottom of the pile embedded in hard rock and the micropile using tilting arrangement, the seismic effect is good. But at the moment, the internal of the micropile is the largest, and the internal force increase amplitude is larger, it is hard to design and construct the micropile and at the same time also can increase the building cost of the projects.In this thesis,the research on slope slope reinforced with micropiles under dynamic load which contribute to a better understanding for the features of micropiles under seismic conditions,to provide a reference for the seismic design of micropile.