土工格室加筋砂土大型动三轴试验研究  

Research on large-scale dynamic triaxial test of geocell-reinforced sand

作　　者：宋飞[1] 陈旺盛 SONG Fei;CHEN Wangsheng(School of Highway Engineering,Chang’an University,Xi’an 710064,China)

机构地区：[1]长安大学公路学院,陕西西安710064

出　　处：《铁道科学与工程学报》2022年第3期683-690,共8页Journal of Railway Science and Engineering

基　　金：陕西省自然科学基金资助项目(2019JM-100);长江水利委员会长江科学院开放研究基金资助项目(CKWV2019743/KY)。

摘　　要：由于土工格室特殊的三维立体形状,对于填料具有较强的侧限约束作用,可以提高填料的强度和刚度,其加固机理与平面加筋材料有显著区别。土工格室加筋土因其优异的力学性能,已被广泛应用于地基处理、边坡加固和防护等工程实践中,但是动荷载作用下格室加筋土的力学性质研究仍然匮乏。为了揭示循环往复荷载作用下土工格室加筋土的应力应变响应规律,以PET土工格室加筋砂土为研究对象,开展系列大型动三轴试验,分析研究土工格室加筋对砂土动应力应变关系、滞回圈和动模量的影响。研究结果表明:当动应变较小时,格室的加固效果不明显,随着累积变形的增加,格室加筋土所能承受的动应力幅值较素砂有显著提高;在素砂与土工格室加筋土动应力幅值相同或接近的工况下,格室加筋土的滞回圈排列紧密,累积塑性变形较小;与素砂相比,土工格室加筋砂土的动模量有显著提升,在300 kPa和500 kPa下动弹性模量分别提高约27.5%和20.57%;此外,在一定应变范围内,对于条带刚度较大的格室,由于轴向变形的增加引起格室约束围压的增大,导致格室加筋土的动模量随动应变的增加而增加;随着围压的提高,格室加筋作用对于累积变形的减小幅度和动模量的提高幅度逐渐衰减;相对于未加筋土,围压的提高对格室土的塑性应变减小幅度影响较小。Due to its special three-dimensional shape, geocell has a strong confining effect on the packing. So it can improve the strength and stiffness of the packing, and its reinforcement mechanism is significantly different from that of the plane reinforced material. Due to its excellent mechanical properties, geocell reinforced soil has been widely used in foundation treatment, slope reinforcement and protection. But the research on the mechanical properties of geocell reinforced soil under dynamic load is still scarce. In order to reveal the stress-strain response of geocellular reinforced soil under cyclic reciprocating load, a series of large-scale dynamic triaxial tests were carried out on PET geocellular reinforced sand to analyze the effects of geocellular reinforcement on dynamic stress-strain relationship, hysteretic cycle and dynamic modulus of sand. The results show that when the dynamic strain is small, the reinforcement effect is not obvious. With the increase of the cumulative deformation, the dynamic stress amplitude of the reinforced soil is significantly higher than that of the plain sand. When the dynamic stress amplitude of plain sand is the same or close to that of geocellular reinforced soil, the hysteretic loops of the geocellular reinforced soil are closely arranged and the cumulative plastic deformation is small.Compared with plain sand, the dynamic modulus of geoly-reinforced sand is significantly increased, and the dynamic elastic modulus of geoly-reinforced sand is increased by 27.5% and 20.57% at 300 kPa and 500 kPa,respectively. In a certain strain range, the dynamic modulus of reinforced soil increases with the increase of dynamic strain due to the increase of confining pressure caused by the increase of axial deformation. With the increase of confining pressure, the decreasing amplitude of the cumulative deformation and the increasing amplitude of the dynamic modulus due to the effect of cellular reinforcement gradually decrease. Compared with unreinforced soil, the increase of confining

关 键 词：土工格室 大型动三轴 动应力应变曲线 滞回曲线 动模量 

分 类 号：U213.1[交通运输工程—道路与铁道工程]