土工合成材料加筋土桥台极限承载力的离心载荷试验  

Centrifuge load test on ultimate bearing capacity of geosynthetic-reinforced soil abutment

作　　者：赵崇熙 徐超[1,2] 王清明 张胜[3] 李昊煜[3] ZHAO Chong-xi;XU Chao;WANG Qing-ming;ZHANG Sheng;LI Hao-yu(Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai 200092,China;Anhui Transport Consulting&Design Institute Co.,Ltd.,Hefei,Anhui 230088,China)

机构地区：[1]同济大学地下建筑与工程系,上海200092 [2]同济大学岩土工程与地下结构教育部重点实验室,上海200092 [3]安徽省交通规划设计研究总院股份有限公司,安徽合肥230088

出　　处：《岩土力学》2024年第6期1643-1650,共8页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.41772284);科技部国家重点研发计划-政府间国际科技创新合作重点专项(No.2016YFE0105800)。

摘　　要：土工合成材料加筋土(geosynthetic-reinforced soil,简称GRS)桥台是桥梁工程的承重结构,对其极限承载力还缺乏清晰的认识。在平面应变条件下开展了5组GRS桥台离心载荷试验,研究了筋材强度、承载区缩进距离和宽度对GRS桥台极限承载力以及破坏模式的影响。试验结果表明,筋材强度对GRS桥台极限承载力影响显著,采用高强度筋材的GRS桥台在加载过程中始终保持稳定。采用低强度筋材的GRS桥台的极限承载力随承载区缩进距离增加而增大,但其增长趋势出现衰减;随承载区域宽度增加,极限承载力降低;现行的半经验半理论公式显著低估了GRS桥台的极限承载力。从试验中和模型拆除后观察,GRS桥台破坏面均从承压区域后缘开始发育,随后向面层方向倾斜向下延伸至约1/2桥台高度处终止;但承载区缩进距离和宽度会影响破坏面的形态和位置。现有方法不能准确地预测GRS桥台破坏面底部终点的位置以及在承载区域下方的形态。增大承载区缩进距离和宽度使得各层筋材应变峰值的位置向桥台内部移动。桥台临空面的存在使得筋材的应变集中于靠近临空面一侧。Geosynthetic-reinforced soil(GRS)abutment is a load-bearing structure in bridge engineering,and its ultimate bearing capacity has not been recognized clearly.In this study,five GRS abutment centrifuge load tests were conducted under plane strain conditions.The effects of reinforcement strength,setback,and width of bearing area on the ultimate bearing capacity and failure mode of GRS abutments were investigated.The results show that the reinforcement strength significantly impacts the ultimate bearing capacity of GRS abutments.GRS abutments using high-strength reinforcement maintained stability during the loading process.It was observed that the ultimate bearing capacity of GRS abutments with low-strength reinforcement increased with the increase of setback,but its growth trend attenuated.As the bearing area width increased,the ultimate bearing capacity decreased.Compared with test results,the current semi-empirical and semi-theoretical formulas significantly underestimate the ultimate bearing capacity of GRS abutments.The observed failure surfaces all developed from the rear edge of the bearing area,extended downward at an angle to the facing,and terminated at approximately 0.5H(H is the GRS abutment height).The setback and width of bearing area affected the form and location of the failure surfaces,as well as the rupture of the reinforcement near the facing.Existing methods cannot accurately predict the bottom endpoint location and morphology below the bearing area of the failure surface.The increase in the setback and width of bearing area caused the peak strain location of each layer reinforcement to shift towards the interior of the abutment.The reinforcement strain concentrated near the free facing side of the abutment.

关 键 词：土工合成材料加筋土 GRS桥台 极限承载力 离心试验 破坏面 

分 类 号：U446[建筑科学—桥梁与隧道工程]