椅式桩板结构地震响应分析与简化计算方法研究  

Seismic Response Analysis and Simplified Calculation Method of Chair⁃shaped Pile⁃sheet Structure

作　　者：左得奇 蒋良潍[1,2] 葛学军[3] 罗强[1,2] 魏明 ZUO Deqi;JIANG Liangwei;GE Xuejun;LUO Qiang;WEI Ming(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Key Laboratory of High-Speed Railway Engineering,Ministry of Education,Chengdu 610031,China;China Railway Eryuan Engineering Group Co.,Ltd.,Chengdu 610031,China)

机构地区：[1]西南交通大学土木工程学院,四川成都610031 [2]高速铁路线路工程教育部重点实验室,四川成都610031 [3]中铁二院工程集团有限责任公司,四川成都610031

出　　处：《防灾减灾工程学报》2021年第3期412-421,共10页Journal of Disaster Prevention and Mitigation Engineering

基　　金：国家自然科学基金项目(52078435,51878560)资助。

摘　　要：椅式桩板结构在高陡边坡路基工程中应用广泛,研究其高烈度地震下的响应特征对抗震分析具有重要意义。以拟建川藏铁路某斜坡椅式桩板结构路基支挡工程为背景,建立有限差分三维数值计算模型,研究了结构的静、动力学响应特性,分析了结构最不利状态响应物理量的取值方法,探讨了结构传力分担机制及重要受力部位,提出了结构地震响应简化计算方法。结果表明:不同地震波形与峰值加速度下,土压力、结构内力及动位移响应的分布曲线形态相似,而响应量值差异显著;土压力应以桩顶动位移朝向临空面达到峰值的时刻作为最不利状态进行取值,而结构各截面的控制内力则应取地震响应时程中的峰值;横梁的推力传递和转角约束作用使主、副桩协同承载且极大增强了结构抗变形能力,桩身与横梁交界位置为结构重要受力部位;考虑拟静力法与动力时程分析结果的响应分布曲线相似性,以最大拟合优度确定动力修正系数取值并提出了地震工况下的结构响应简化计算方法。The chair-shaped pile-sheet structure is a type of retaining structure used for subgrades with high-steep slopes,and there is great significance to study its high-intensity seismic response characteris‑tics.Based on the proposed construction of the chair-shaped pile-sheet structure of the subgrade of the Si‑chuan-Tibet Railway on a slope,a three-dimensional finite-difference numerical model is established to study the static and dynamic response characteristics of the structure,and the optimal method on how to determine the value of response physical quantity in the most unfavorable state is analyzed.In addition,the mechanism of force transmission and sharing and the important loading parts are explored,and the simplified calculation method for seismic response is proposed.The results show that:the distribution curves of earth pressure,structural internal force,and dynamic displacement response under different seismic waveforms and peak accelerations have similar shapes,while the response magnitude is signifi‑cantly affected by the acceleration amplitude and seismic waveform;the earth pressure should be taken as the most unfavorable state when the dynamic displacement of the pile top reaches its peak value towards the empty surface,and the controlling internal force of each section of the structure should be taken as the peak value in the seismic response time history;the thrust transmission and the corner restraint of the beam make the main and auxiliary piles bear the load together and greatly enhance the deformation resis‑tance of the structure.The junction of the pile body and the beam is an important part of the structure;con‑sidering the similarity of the response distribution curves of the quasi-static method and the dynamic time history analysis,the value of the dynamic correction coefficient is determined using the goodness of fit and a simplified calculation method for structural response under seismic conditions is proposed.

关 键 词：椅式桩板结构 地震响应 数值分析 响应分布曲线 动力修正系数 

分 类 号：TU435[建筑科学—岩土工程]