Three-Dimensional Soil-Pile Group Interaction in Layered Soil with Disturbed Zone by Boundary Element Analysis
Three-Dimensional Soil-Pile Group Interaction in Layered Soil with Disturbed Zone by Boundary Element Analysis
复制标题
扰动区层状土体三维土桩群相互作用的边界元分析
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
Zhiyan Jiang
中科院分区：
文献类型：
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作者：
J. Ashlock;Zhiyan Jiang
具有扰动区的层状地基中的三维土-桩相互作用爱荷华州立大学的Jeramy Ashlock和Jhiyan酱作为当前土-桩动力相互作用研究项目的一部分，对并行边界元方法(BEM)程序BEASSI进行了修改，使之能够分析被多个多层土层包围的群桩的三维动力特性，并严格考虑了辐射和材料阻尼。然后在频域分析了单桩和2×2群桩的土-桩动力相互作用，每个群桩周围都有一个内扰动区和一个外半空间区。层状内层可以近似考虑土体的非均质性、桩的安装、应变相关的弹性模量值和阻尼值的影响，而外层半空间的层状结构可以考虑远场波在垂直非均匀土体中的传播。通过与文献中的静态和动态基准解进行比较，验证了修改后代码的性能。文中还给出了利用边界元分析中的阻抗函数分析群桩动力响应的一般公式，将地上桩段模型化为梁柱，将承台视为刚体。对于2×2群桩的情况，建立了24×24的整体刚度矩阵，以反映桩-土-桩相互作用引起的每根桩的六个位移自由度对其他桩的影响。通过分别在每个桩的土面高程处施加位移来验证整体刚度矩阵的形式和对称性，从而通过仅指定其中一个桩的位移来更有效地执行未来的分析。通过对即将进行的群桩全尺寸振动试验的分析，本研究的结果将为建立校准的计算连续介质模型奠定基础。
Three-Dimensional Soil-Pile Group Interaction in Layered Soil with Disturbed-Zone by Boundary Element Analysis Jeramy Ashlock and Zhiyan Jiang, Iowa State University As part of a current research project on dynamic soil-pile interaction, the parallelized Boundary Element Method (BEM) code BEASSI was modified to enable analysis of three-dimensional dynamic behavior of pile groups surrounded by multiple multi-layered soil zones, with rigorous account of radiation and material damping. Dynamic soil-pile interaction was then analyzed in the frequency domain for a single pile and a 2×2 pile group, each surrounded by an inner disturbed-zone and an outer half-space zone. The layered inner zone enables effects of inhomogeneity, pile installation, and strain-dependent modulus and damping to be approximated, while the outer layered half-space zone can account for the far-field wave propagation in a vertically heter-ogeneous soil medium. The performance of the modified code is validated by comparison to static and dynamic benchmark solutions from the literature. A general formulation for analyzing the dynamic response of pile groups using impedance functions from the BEM analysis is also presented, with the above-ground pile segments modeled as beamcolumns and the pile cap treated as a rigid body. For the present case of the 2×2 pile group, a 24×24 global stiffness matrix is formulated to capture the influence of each pile’s six displacement degrees-offreedom on the other piles due to pile-soil-pile interaction. The form and symmetries of the global stiffness matrix are verified by imposing displacements at the soil surface elevation for each pile crosssection separately, enabling future analyses to be performed more efficiently by specifying displacements at only one of the piles. Results of this study will lay the foundation for developing calibrated computational continuum models by analyzing upcoming full-scale vibration tests of pile groups.