Seismic Behavior of Unconnected Piles–Caisson Foundation Using Slow Cyclic Tests

IF 2.1 4区工程技术 Q2 GEOCHEMISTRY & GEOPHYSICS

Journal of Earthquake and Tsunami Pub Date : 2021-02-16 DOI:10.1142/S179343112150024X

Lu Yang, Feng Shengming, Gong Wei-ming, Dai Guo-liang, Zhao Xueliang

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引用次数: 0

Abstract

The unconnected piles–caisson foundation (UPCF) consists of gravity caisson, mattress, and pile group. This foundation has been an attractive design for the mattress as it can reduce the seismic loads applied on the superstructure. However, a lack of understanding regarding its seismic behavior has hindered the application of this type of foundation. This paper reports on a series of slow cyclic tests (SCTs) conducted to investigate the seismic behavior of the UPCF. Six tests were conducted on model foundations on dry sand with the variables of mattress material, mattress thickness, vertical safety factor, and ground improvement. The experimental schemes, including the model design, the instrumentation, and the loading scheme, are illustrated in detail. The test results show that a large amount of energy was dissipated through the mattress during dynamic loading. With increasing loading displacement, the shear stiffness of these models decreased to a stable value. An empirical equation for the stiffness and loading displacement is developed. Below a drift ratio of 0.6%, there is no evident difference in the dynamic behavior of the foundation. After that, the aseismic behavior of the foundation depends on the mattress material, the mattress thickness, and the vertical pressure and is affected by the earthquake intensity and frequency.

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非连体桩-沉箱基础慢循环试验抗震性能研究

非连体桩沉箱基础由重力沉箱、垫层和群桩组成。这种基础是床垫的一个有吸引力的设计，因为它可以减少施加在上部结构上的地震载荷。然而，由于对其抗震性能的认识不足，阻碍了这种地基的应用。本文报道了一系列慢循环试验(sct)，以研究UPCF的抗震性能。采用垫层材料、垫层厚度、垂直安全系数、地基改良率等变量，在干砂模型基础上进行了6次试验。详细介绍了实验方案，包括模型设计、仪器设计和加载方案。试验结果表明，在动加载过程中，床垫会耗散大量能量。随着加载位移的增大，这些模型的抗剪刚度逐渐趋于稳定。建立了刚度与加载位移的经验方程。当位移比小于0.6%时，地基动力性能无明显差异。之后，基础的抗震性能取决于垫层材料、垫层厚度和竖向压力，并受地震烈度和频率的影响。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Earthquake and Tsunami 地学-地球化学与地球物理

CiteScore

2.60

自引率

13.30%

发文量

审稿时长

>12 weeks

期刊介绍： Journal of Earthquake and Tsunami provides a common forum for scientists and engineers working in the areas of earthquakes and tsunamis to communicate and interact with one another and thereby enhance the opportunities for such cross-fertilization of ideas. The Journal publishes original papers pertaining to state-of-the-art research and development in Geological and Seismological Setting; Ground Motion, Site and Building Response; Tsunami Generation, Propagation, Damage and Mitigation, as well as Education and Risk Management following an earthquake or a tsunami. We welcome papers in the following categories: Geological and Seismological Aspects Tectonics: (Geology - earth processes) Fault processes and earthquake generation: seismology (earthquake processes) Earthquake wave propagation: geophysics Remote sensing Earthquake Engineering Geotechnical hazards and response Effects on buildings and structures Risk analysis and management Retrofitting and remediation Education and awareness Material Behaviour Soil Reinforced concrete Steel Tsunamis Tsunamigenic sources Tsunami propagation: Physical oceanography Run-up and damage: wave hydraulics.