| 层状土场中冲刷作用下部分埋置单桩动力响应分析 |
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| 引用本文： | 马建军,韩书娟,高笑娟,李达,郭颖.层状土场中冲刷作用下部分埋置单桩动力响应分析[J].岩土力学,2022,43(6):1705-1716. |
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| 作者姓名： | 马建军 韩书娟 高笑娟 李达 郭颖 |
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| 作者单位： | 1. 河南科技大学 土木工程学院，河南 洛阳 471023；2. 河南科技大学 河南省建筑安全与防护工程技术研究中心，河南 洛阳 471023 |
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| 基金项目： | 国家自然科学基金（No.11502072）； |
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| 摘 要： | 桩周土场受冲刷作用的变化是部分埋置单桩结构失效的主要原因之一。工程中土场多呈层状，此类场地中桩基的力学特性研究日益受到关注。为精确揭示冲刷作用对层状土场中部分埋置单桩动力响应的影响，基于改进Vlasov地基模型，利用Hamilton原理建立层状土场中横向受荷单桩的动力学模型。利用有限差分法求解受冲刷作用单桩的固有频率，实现对冲刷作用下土?结构相互作用系统的准确建模，进而用Green函数法求得单桩受迫振动的解析解。通过数值计算和参数分析，研究了层状土场的物理特性对受冲刷作用部分埋置单桩动力响应的影响。结果表明：基于改进Vlaosv地基模型建立的层状土场中部分埋置单桩动力学模型可精确预测冲刷作用对桩基动力学特性的影响。随冲刷程度加剧，层状土场中单桩的第一阶固有频率显著降低，改进Vlasov地基模型中各层土体的地基反力系数均减小，剪切系数则增大。当冲刷至非埋置段桩长 （ 为桩长）时，部分埋置单桩在动荷载作用下出现横向失稳现象。随底层土体厚度增加，各冲刷等级下单桩的第一阶固有频率均增大。如果第1层土的弹性模量增大了约0.43倍、1.14倍、1.86倍，则冲刷等级为0时单桩第一阶固有频率分别增大了约8.9%、19.5%、27.1%。
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| 关 键 词： | 部分埋置单桩 层状土场 改进Vlasov地基模型 冲刷作用 有限差分法 Green函数法 |
| 收稿时间： | 2021-09-14 |
| 修稿时间： | 2022-03-03 |
Dynamic response analysis of the partially-embedded single pile affected by scour in layered soils |
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| MA Jian-jun,HAN Shu-juan,GAO Xiao-juan,LI Da,GUO Ying.Dynamic response analysis of the partially-embedded single pile affected by scour in layered soils[J].Rock and Soil Mechanics,2022,43(6):1705-1716. |
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| Authors: | MA Jian-jun HAN Shu-juan GAO Xiao-juan LI Da GUO Ying |
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| Institution: | 1. School of Civil Engineering, Henan University of Science and Technology, Luoyang, Henan 471023, China; 2. Engineering Technology Research Center of Safety and Protection of Buildings of Henan Province, Henan University of Science and Technology, Luoyang, Henan 471023, China |
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| Abstract: | The change of the soils around pile affected by scour is one of the major causes for the failure of structure of the partially-embedded single pile. The soil fields in engineering are mostly layered, and the research on the mechanical characteristics of pile foundation in layered soils has attracted increasing attention. In order to accurately reveal the effect of scour on the dynamic response of the partially-embedded single pile in layered soils, a dynamic model of the laterally loaded single pile in layered soils is established by employing Hamilton’s principle based on the modified Vlasov foundation model. Then, the finite difference method is used to solve the natural frequencies of the single pile affected by scour, and to achieve accurate modeling of the soil-structure interaction (SSI) system affected by scour. Analytical solution of the forced vibration of the single pile is obtained by Green’s function method. The effects of physical characteristics of the layered soils on the dynamic response of the partially-embedded single pile are studied by numerical calculation and parameter analysis. The results show that the dynamic model of the partially-embedded single pile in layered soils based on the modified Vlaosv foundation model can accurately predict the impact of scour on its dynamic characteristics. As the scour degree intensifies, the first-order natural frequencies of the single pile in layered soils decrease significantly, and the subgrade reaction coefficient of each layer of soils in the improved Vlasov foundation model decreases, and the shear coefficient increases. When the length of the non-embedded section of the pile satisfies ( is the pile length), the lateral instability of the partially embedded single pile is observed under the dynamic load. As the thickness of the underlying soil increases, the first-order natural frequencies of the single pile at each scour level increase. As the elastic modulus of the first layer of soil increases by about 0.43 times, 1.14 times, and 1.86 times, the first-order natural frequencies of the single pile at the scour level of 0 increase by about 8.9%, 19.5%, and 27.1%. |
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| Keywords: | partially-embedded single pile layered soils modified Vlasov foundation model scour effect finite difference method Green’s function method |
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