纤维加筋砂土抗液化试验与数值模拟  

EXPERIMENTAL AND NUMERICAL MODELING ON LIQUEFACTION RESISTANCE OF FIBER REINFORCED SAND

作　　者：周林禄 苏雷 凌贤长[1] 刘秀 关达 张永强[3] ZHOU Linlu;SU Lei;LING Xianzhang;LIU Xiu;GUAN Da;ZHANG Yongqiang(School of Civil Engineering,Qingdao University of Technology,Qingdao 266033,China;CHN Energy Baoshen Railway Group Co.,Ltd.,Baotou 014010,China;Inner Mongolia University of Science&Technology,Baotou 014010,China)

机构地区：[1]青岛理工大学土木工程学院,青岛266033 [2]国能包神铁路集团有限责任公司,包头014010 [3]内蒙古科技大学,包头014010

出　　处：《工程地质学报》2021年第5期1567-1576,共10页Journal of Engineering Geology

基　　金：国家自然科学基金项目(资助号:51808307,42072310)。

摘　　要：砂土液化是导致重大地震灾害的主要原因之一。本研究探讨了天然纤维加筋砂土在循环荷载作用下的抗液化性能。在不排水条件下,对具有不同纤维含量的加筋砂土试样进行了一系列循环三轴试验,研究了饱和砂土的液化特性以及循环剪应变幅值、纤维含量对饱和砂土抗液化性能的影响。此外,通过模拟已完成的循环三轴试验,建立了二维有限元数值模型,并对具有不同纤维含量的加筋砂土进行了参数标定。研究结果表明:(1)增加循环剪应变幅值将促进超孔压累积,使得滞回曲线斜率和平均有效应力减小速度加快;(2)纤维的存在能够减缓超孔压的累积,随着纤维含量增加,加筋砂土抗液化能力得到明显提高;(3)标定后的本构模型参数能可靠地用于模拟纤维加筋砂土的液化响应。研究结果为饱和砂土抗液化问题与纤维加筋砂土的数值模拟提供了有价值的参考。Sand liquefaction is one of main reasons leading to severe earthquake disasters.In this study,liquefaction resistance of sand reinforced by natural fiber under cyclic loading is discussed.A series of cyclic triaxial tests is carried out on reinforced sand specimens with different fiber contents under undrained conditions.The influence of cyclic shear strain amplitude and fiber content on liquefaction resistance of saturated sand is studied.Furthermore,a two-dimensional finite element numerical model for simulating finished cyclic triaxial test is established.The parameter calibration of reinforced sand with different fiber contents is performed.The results show that:(1)Increasing the amplitude of cyclic shear strain can promote the accumulation of excess pore pressure,which can speed up the reduction of slope of hysteresis loops and mean effective stress.(2)The presence of fiber can mitigate the accumulation of excess pore pressure,and liquefaction resistance of reinforced sand is significantly improved with increase of fiber content.(3)Calibrated constitutive model parameters can be reliably used to simulate liquefaction response of fiber reinforced sand.The results provide a valuable reference for liquefaction resistance of saturated sand and the numerical modeling of fiber reinforced sand.

关 键 词：饱和砂土 纤维 抗液化 循环三轴试验 参数标定 

分 类 号：TU411.8[建筑科学—岩土工程]