地震作用下液化场地变截面桩与等截面桩的动力响应对比分析  

Comparative analysis of dynamic response between variable section pile and constant section pile in liquefaction siteunder earthquake action

作　　者：冯忠居[1] 王逸然 张俊波 张建斌 孟莹莹 赵瑞欣 FENG Zhongju;WANG Yiran;ZHANG Junbo;ZHANG Jianbin;MENG Yingying;ZHAO Ruixin(School of Highway,Chang'an University,Xi'an 710064,China;Xiamen Road and Bridge Engineering Investment and Development Co.,Ltd.,Xiamen 361006,China)

机构地区：[1]长安大学公路学院,陕西西安710064 [2]厦门路桥工程投资发展有限公司,福建厦门361006

出　　处：《世界地震工程》2022年第3期59-69,共11页World Earthquake Engineering

摘　　要：为研究液化场地变截面桩的动力响应,依托翔安大桥实体工程,采用有限元软件,建立变截面桩-土和等截面桩-土相互作用模型,模拟液化场地变截面桩及等截面桩在地震作用下的振动反应,分析在地震作用下变截面位置不同的变截面桩及等截面桩的动力响应特征。结果表明:地震作用下,液化土层不同深度处的孔压比变化规律基本相同,均从0逐渐增大最后趋于稳定;变截面桩的桩身加速度和桩身位移均大于等截面桩,且桩顶加速度峰值出现的时刻均滞后于桩底;在饱和砂土层处,桩身位移变化趋势均较陡;变截面桩的桩身弯矩峰值和桩身剪力峰值均大于等截面桩,且其峰值出现的位置较等截面桩深;地震作用下,变截面桩及等截面桩的弯矩与剪力均在安全范围之内;液化场地变截面梁桥桩基础抗震设计时,应着重分析液化土层与非液化土层分界面以下的抗弯能力设计及液化土层中抗剪能力设计。In order to study the dynamic response of variable cross-section piles in the liquefaction site,relying on the physical engineering of Xiang'an Bridge,finite element software is used to establish variable-section pile-soil and constant-section pile-soil interaction models to simulate variable-section piles and constant-section piles in liquefaction site.Vibration response under earthquake action,analysis of variable cross-section position under the seismic action of different variable cross-section pile and the dynamic response characteristics of equal section pile.The results show that the acceleration and displacement of the variable section pile are greater than those of the constant section pile,and the peak of the acceleration of the pile top lags behind the bottom of the pile.In the saturated sand layer,the pile displacement variation trend is steeper.The peak values of bending moment and shear force of variable section piles are larger than those of constant section piles,and their peak values are deeper than those of constant section piles.Under the earthquake action,the bending moment and shear force of variable section pile and equal section pile are within the safe range.In the seismic design of variable section beam pile foundation in liquefaction site,the design of flexural capacity below the boundary of liquefaction and non-liquefaction soil layer and the design of shear capacity in liquefaction soil layer should be considered emphatically.

关 键 词：岩土工程 液化场地 大直径变截面桩基础 数值模拟 动力响应 

分 类 号：TU473.1[建筑科学—结构工程]