土工基础

土工基础 ›› 2019, Vol. 33 ›› Issue (6): 683-689.

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蘑菇形短桩橡胶砂复合垫层动力特性研究

针对橡胶砂竖向模量不足的问题，提出了用蘑菇形短桩对其进行加筋，以保证其在有一定隔震性能的情况下，竖向变形大幅度减小。通过Marc有限元软件对不同样式的蘑菇形短桩-橡胶砂（MP-RSM）复合隔震装置做循环剪切模拟，对比分析了不同桩冠偏角θ和桩腹直径d对该复合装置动力性能的影响以及加筋对RSM竖向变形的影响。结果表明：①在应变较小时，MP-RSM复合垫层的动剪模量随着桩冠偏角的增大而逐渐增大并趋于平缓，而在应变较大时，其受桩冠偏角的影响很小；随着桩腹直径的增大，复合垫层的动剪模量略有增大，但是变化并不明显；②桩腹直径相同时，随着桩冠偏角的增大，同样动剪应变下的复合垫层阻尼比逐渐增大且趋于平缓；桩腹直径的变化对复合垫层阻尼比影响并不明显；③该复合隔震垫层具有变水平刚度和良好的滞回耗能特性，且可以有效地减小橡胶砂的竖向变形，可用作隔震垫层。   

  1. （湖南工业大学土木工程学院，湖南株洲 412007）
  • 收稿日期:2019-02-25 修回日期:2019-03-18 出版日期:2019-12-28 发布日期:2019-12-28
  • 通讯作者: 刘方成（1978-），男，副教授，博士，研究方向为新型岩土隔震系统。
  • 作者简介:姚玉文(1994-)，男，硕士研究生，研究方向为土动力特性、结构隔震与减震。
  • 基金资助:
    国家自然科学基金项目资助（51108177,51708205）

Study of Dynamic Characteristics of Mushroom Shaped Short Pile in Rubber-Sand Mixture Composite Cushion

The rubber-sand-mixture soil is usually lack of the required vertical modulus, a short mushroom-shaped pile is then proposed to reinforce it so as to reduce the vertical deformation dramatically under the condition that it has certain isolation performance. The cyclic shear simulation of the mushroom shaped short pilerubber sand mixture (MP-RSM) composite isolation device is carried out by Marc that is a type of finite element software. The effects of different pile crown deviation angle θand pile belly diameter d on the dynamic performance of the composite device and the effect of reinforcement on the vertical deformation of RSM are compared and analyzed. The results show that: 1) when the strain is small, the dynamic shear modulus of MP-RSM composite cushion gradually increases and tends to be flat with the increase of the pile crown deflection angle, while when the strain is large, the influence of the pile crown deflection angle is small; with the increase of the diameter of pile belly, the dynamic shear modulus of composite cushion increases slightly, but the change is not obvious; 2) when the diameter of pile belly is the same, the dynamic shear modulus of MP-RSM composite cushion increases with the increase of the pile crown the damping ratio of composite cushion increases gradually and tends to be gentle under the shear strain; the influence of the diameter of pile web on the damping ratio of composite cushion is not obvious; 3) The composite cushion has variable horizontal stiffness and good hysteretic energy dissipation characteristics, and can effectively reduce the vertical deformation of rubber sand, which can be used as isolation cushion.   

  1. (College of Civil Engineering, Hunan University of Technology, Zhuzhou 412007)
  • Received:2019-02-25 Revised:2019-03-18 Online:2019-12-28 Published:2019-12-28

摘要： 针对橡胶砂竖向模量不足的问题，提出了用蘑菇形短桩对其进行加筋，以保证其在有一定隔震性能的情况下，竖向变形大幅度减小。通过Marc有限元软件对不同样式的蘑菇形短桩-橡胶砂（MP-RSM）复合隔震装置做循环剪切模拟，对比分析了不同桩冠偏角θ和桩腹直径d对该复合装置动力性能的影响以及加筋对RSM竖向变形的影响。结果表明：①在应变较小时，MP-RSM复合垫层的动剪模量随着桩冠偏角的增大而逐渐增大并趋于平缓，而在应变较大时，其受桩冠偏角的影响很小；随着桩腹直径的增大，复合垫层的动剪模量略有增大，但是变化并不明显；②桩腹直径相同时，随着桩冠偏角的增大，同样动剪应变下的复合垫层阻尼比逐渐增大且趋于平缓；桩腹直径的变化对复合垫层阻尼比影响并不明显；③该复合隔震垫层具有变水平刚度和良好的滞回耗能特性，且可以有效地减小橡胶砂的竖向变形，可用作隔震垫层。

关键词: 低成本隔震, 橡胶砂, 蘑菇形短桩, 动力特性, 数值模拟

Abstract: The rubber-sand-mixture soil is usually lack of the required vertical modulus, a short mushroom-shaped pile is then proposed to reinforce it so as to reduce the vertical deformation dramatically under the condition that it has certain isolation performance. The cyclic shear simulation of the mushroom shaped short pilerubber sand mixture (MP-RSM) composite isolation device is carried out by Marc that is a type of finite element software. The effects of different pile crown deviation angle θand pile belly diameter d on the dynamic performance of the composite device and the effect of reinforcement on the vertical deformation of RSM are compared and analyzed. The results show that: 1) when the strain is small, the dynamic shear modulus of MP-RSM composite cushion gradually increases and tends to be flat with the increase of the pile crown deflection angle, while when the strain is large, the influence of the pile crown deflection angle is small; with the increase of the diameter of pile belly, the dynamic shear modulus of composite cushion increases slightly, but the change is not obvious; 2) when the diameter of pile belly is the same, the dynamic shear modulus of MP-RSM composite cushion increases with the increase of the pile crown the damping ratio of composite cushion increases gradually and tends to be gentle under the shear strain; the influence of the diameter of pile web on the damping ratio of composite cushion is not obvious; 3) The composite cushion has variable horizontal stiffness and good hysteretic energy dissipation characteristics, and can effectively reduce the vertical deformation of rubber sand, which can be used as isolation cushion.

Key words: Low-cost Seismic Isolation Technology, Rubber-Sand Mixture, Mushroom Shaped Short Piles, Dynamic Characteristics, Numerical Simulation

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