摘要
相比传统实心桩,大直径现浇混凝土管桩在相同混凝土消耗的前提下拥有更高的承载能力和动力学刚度,但其低应变检测理论仍然滞后于工程应用。具体而言,饱和土体中的土塞效应和由于横向惯性效应导致的反射波震荡这两者对检测结果的影响仍然不清晰,亟需建立严格的桩周土-管桩-土塞模型来弥补这一空白。因此,采用Biot多孔介质连续方程模拟饱和土中水土两相介质间的相互作用,从能量法的角度考虑桩体的横向变形,修正了适用于管桩基础的Rayleigh-Love杆件模型,并将两者通过桩土界面关系进行耦合求解。通过傅里叶变换、势函数解耦偏微分方程以及分离变量法等数学手段求解了桩周土与桩芯土的径向和纵向位移函数,而后采用傅里叶逆变换得到半正弦脉冲下桩顶纵向振动速度时域响应解析解,并通过与前人的解进行对比,验证了该解的正确性。结果表明:管桩泊松比越高,桩底反射信号幅值越小,反射波震荡效应越明显;管桩壁厚越大,桩底反射信号幅值越大;桩芯土模量越小,反射波的震荡效应越明显。
Compared with traditional solid pile,large-diameter cast-in-situ concrete pipe pile has higher load-bearing capacity and dynamic stiffness under the same concrete consumption,but its low strain detection theory still lags behind engineering application.Specifically,influence of soil plug effect in saturated soil and reflected wave oscillation caused by lateral inertia effect on the detection results is still unclear,and it is urgent to establish a strict soil-pipe pile-soil plug model around pile forfilling this gap.Here,Biot porous medium continuity equation was used to simulate interaction between water and soil in saturated soil,lateral deformation of pile was considered from the perspective of energy method to modify Rayleigh-Love rod model applicable to pipe pile foundation,and the two equationsweresolved through pile-soil coupledinterface relation.Radial and longitudinal displacement functions of soil around pile and pile core soil were solved using Fourier transform,potential function decoupling partial differential equations and variable separation method,and then the time domain response analytical solution to longitudinal vibration velocity at pile top under half sine pulse was obtained using inverse Fourier transform.Compared with the solution published in literature,the correctness of the solution obtained herewas verified.It was shown that the higherthe pipe pile’s Poisson ratio,the smaller the amplitude of reflected signal at bottom of pipe pile,and the more obvious the oscillation effect of reflected wave;the larger the pipe pile wall thickness,the larger the amplitude of reflected signal at pipe pile bottom;the smaller the modulus of pile core soil,the more obvious the oscillation effect of reflected wave.
作者
邸同宇
吴文兵
张云鹏
刘浩
DI Tongyu;WU Wenbing;ZHANG Yunpeng;LIU Hao(Faculty of Engineering,China University of Geosciences,Wuhan 430074,China;Zhejiang Institute,China University of Geosciences,Hangzhou 311305,China)
出处
《振动与冲击》
EI
CSCD
北大核心
2023年第1期160-168,共9页
Journal of Vibration and Shock
基金
国家自然科学基金面上项目(51878634)
浙江省杰出青年基金项目(LR21E080005)
中央高校基本科研业务费(1910491T04)。
关键词
管桩
横波干扰
饱和土
低应变测试
纵向振动
时域响应
pipe pile
transverse wave interference
saturated soil
low strain test
longitudinal vibration
response in time domain
