软土地区有轨电车线路复合桩板结构路基受力特性分析  

Analysis on the Mechanical Characteristics of Composite Pile-plank Structure Subgrade for Tram Line in Soft Soil Area

作　　者：王长丹[1,2] 周伟 姚青 散骞骞 陈凯祥 WANG Changdan;ZHOU Wei;YAO Qing;SAN Qianqian;CHEN Kaixiang(Shanghai Key Laboratory of Rail Infrastructure Durability and System Safety,Tongji University,201804,Shanghai,China;不详)

机构地区：[1]同济大学道路与交通工程教育部重点实验室,上海201804 [2]上海市轨道交通结构耐久与系统安全重点实验室,上海201804 [3]上海城建市政工程(集团)有限公司,上海200131

出　　处：《城市轨道交通研究》2023年第11期1-6,共6页Urban Mass Transit

基　　金：国家自然科学基金面上项目(51778485);青年科学基金项目(51608384)。

摘　　要：目的:有轨电车线路如选用桩板结构作为其路基形式,将极大地增加工程造价。与之相比,复合桩板结构路基造价较低,且能充分发挥桩-板-土的协同受力作用,需对有轨电车线路复合桩板结构路基的受力特性进行深入研究。方法:依托上海松江有轨电车示范线工程,对深厚软土地区复合桩板结构路基的受力变形特性进行了阐述。采用数值模拟方法,详细分析了该工程在运营期和建设期的复合桩板结构路基跨中板下土体、桩体和桩土的受力变形特性,并进一步分析了不同桩长条件下复合桩板结构路基的力学性能。结果及结论:跨中板下土体的附加应力随埋深增加呈现先减小后增大再减小的变化规律,且在桩底下方1~2 m处达到峰值;桩体的承载力主要由桩侧摩阻力提供,桩侧土体与跨中板下土体间的差异沉降值与桩侧摩阻力呈正相关关系;随着荷载的增大,桩侧摩阻力自下而上逐渐达到极限值;随着桩体长度的增加,板下土体沉降量逐渐减小,且在桩体极限承载力范围内,适当减小桩体长度并不会显著减小桩体所能承担的上部荷载大小。Objective:Choosing pile slab structure as the subgrade form for tramline will significantly increase the construction cost.In contrast,the cost of the composite pile-plank structure foundation is lower,and it can fully utilize the synergistic force between the pile,slab,and soil.Therefore,it is necessary to conduct an in-depth study on the mechanical characteristics of the composite pile-plank structure subgrade for tramline.Method:Based on the tram demonstration line project in Shanghai Songjiang,the stress and deformation characteristics of the composite pile-plank structure subgrade in deeply soft soil areas are elaborated.By using numerical simulation methods,the stress and deformation characteristics of the soil,pile body,and pile-soil under the subgrade middle plank are analyzed in detail during operation and construction periods of the project.Furthermore,the mechanical properties of the composite pile-plank structure subgrade under different pile lengths are analyzed.Result&Conclusion:The additional stress on the soil under the mid span slab shows a pattern of first decreasing,then increasing,and finally decreasing again with increasing depth,reaching a peak value at a depth of 1-2 m below the pile bottom;the bearing capacity of the pile is mainly provided by the lateral friction resistance of the pile,and the differential settlement value between the lateral soil and the soil under the mid span slab is positively correlated with the lateral friction resistance;with the increase of load,the lateral friction resistance gradually reaches the limit value from bottom to top;as the pile length increases,the settlement of the soil under the plate gradually decreases,keeping within the range of the ultimate bearing capacity of the pile.Appropriately reducing the length of the pile will not significantly reduce the size of the upper load that the pile can bear.

关 键 词：有轨电车线路 深厚软土地区 复合桩板结构路基 受力特性 

分 类 号：TU43[建筑科学—岩土工程] U482.1[建筑科学—土工工程] U213.24[交通运输工程—载运工具运用工程]