Study On The Performance-based Seismic Design Method Application To Pile-anchor Retaining Structure

The pile-anchor retaining structure system is applied in the field of slope support because of its good mechanical properties and deformation control function of slope. As it involves piles, prestressed anchor cables and soil mass, the interaction among them is complicated. The key of interaction mechanism among piles, prestressed anchor cables and soil mass is coordinated deformation and co-working conditions of piles and prestressed anchor cables. Meanwhile, to ensure the safety and function of pile-anchor retaining structure, it is necessary to conrol the deformation of retaining structure reasonably. The traditional design method of retaining structure mainly analyzes the safety of slope instead of its deformation performance. The performance-based seismic design method ensures structures to meet the expected requirement of seismic performance by setting performance index conditions. Although a certain research achievements have been obtained in seismic design of buildings and bridges, the application of performance-based seismic design method of retaining structure system in slope is so little. So the stress mechanism of the pile-anchor retaining structure system based on controlling deformation is researched in the paper according to the coordinated deformation and co-working analysis of piles and prestressed anchor cables.The performance-based seismic design method is applied to the design of pile-anchor retaining structures, its deformation-based design method and the deformation performance indexs are proposed in this paper. Finally, the design method of pile-anchor retaining structure system presented in this paper is verified by project case studies. The main reaserch contents and achievements of this paper are summarized as follows:â‘ The interaction mechanism of the pile-anchor retaining structure system in bedding rock slope are analyzed, the improved coordinated deformation conditions and its co-working conditions are presented. Then, the stress mechanism of pile-anchor retaining structure based on deformation control is studied, and anchor cable tension calculation formulas and stress and displacement calculation formulas of piles are deduced based on it in this paper.â‘¡According to the comparion analysis between the performance-based seismic design method and current seismic codes, the performance-based seismic design method is applied in the design of pile-anchor retaining structures and the author proposes thepeformance levels, codes of the performance-based seismic design, and the framework of the performance-based seismic design of pile-anchor retaining structure is constructed in this paper.â‘¢According to the rules of displacement control in some countries and the stress mechanism and failure formation analysis of the pile-anchor retaining structure system,the paper suggests the displacement of pile top and the relative displacement index of anchor head as performance indexs of pile-anchor retaining structure system. According to the result of numerical simulation, the stress and deformation regularity of pile-anchor retaining structure are analyzed. According to the function of buildings around it and deformation control standard of slope monitoring norm,quantify values of performance indexs under safety assessment level are conformed in specific project.â‘£The improved coordinated deformation equation and co-working equation are applied to the design of the pile-anchor retaining structure system of specific project.The seismic performance of its design results is evaluated with the performance-based seismic design method. And the monitoring results of this project verify the reasonability and feasibility of this design method based on the improved coordinated deformation equation and co-working equation.