Study On Dynamic Response Characteristics Of Reinforced Slope With Micropiles And The Aseismic Analysis Method

The frequent occurrences of earthquakes cause losses increasing in recent years, so the design of support structures under earthquake condition is particularly important, the issues about seismic slope reinforcement has received more and more attention. The micro-pile is a new type of support structure which developed in recent twenty years. For the short history of application, the theory of design and calculation about micro-pile composite structures has not yet satisfactory, especially the research on characteristics, mechanism of reinforcement and failure mode of the micro-pile is quite lacked. The paper employs FLAC software to discuss the issues related to micro-piles under dynamic loads based on previous studies. The main contents of this paper have two parts:the dynamic response characteristics of slope with micro-piles and the seismic design method of the micro-pile composite structure.The paper has comparatively analyzed the failure mechanism of slope without piles under static and dynamic condition through finite element calculation, and then analyzed the affect of ground motion parameters, such as frequency, amplitude and duration, on the dynamic response of slopes without piles. Based on the determinate unfavorable parameters, it has calculated and analyzed the dynamic response characteristics of slope with different micro-pile composite structures, including different pile rows (two rows, three rows, four rows) and different pile roof thickness (0.1m,0.3m,0.5m,0.7m). According to different dynamic response characteristics and internal forces, decide to choose the composite structures with9piles (3×3) on three rows and0.5m thick pile roof to design.For the determinate and appropriate composite structures, based on the dynamic response characteristics, there are tow seismic calculation methods are obtained, which are simplified dynamic calculation method and pseudo-static method. The calculation includes tow main parts:(1) to simplify the lateral load distribution pattern at the sides of loading segment of micro-pile under static and dynamic loads:(2) to calculate the internal force through dynamic load distribution pattern simplified and the static load magnified, and compare the theoretical calculations with numerical simulation values, the difference between which is at the range of20%, indicating that the simplified calculation method is more feasible.In this thesis, the research on slope reinforced with micro-piles under dynamic load. which contribute to a better understanding for the features of micro-piles under seismic conditions, to provide a reference for the seismic design of micro-pile.