Torsional vibrations of a cylindrical foundation embedded in a saturated poroelastic half-space

doi:10.1007/s11709-015-0292-z

Front. Struct. Civ. Eng.

2015, Vol. 9

Issue (2) : 194-202 https://doi.org/10.1007/s11709-015-0292-z

RESEARCH ARTICLE

Torsional vibrations of a cylindrical foundation embedded in a saturated poroelastic half-space

Dazhi WU,Lu YU(

)

School of Civil Engineering and Architecture, Zhejiang Sci-Tech University, Hangzhou 310018, China

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Abstract

Considering the interactions between an embedded foundation and saturated soil, the torsional vibrations of a cylindrical foundation embedded in a saturated poroelastic medium are analyzed in this paper. Both a rigid foundation and an elastic foundation are considered. Assuming both the side surface and the bottom surface of the foundation are perfectly bonded to soil, the reaction torques that the side soil and bottom soil acting on the foundation can be gained from basic dynamic equations of the poroelastic medium. According to the dynamic equilibrium equations of a foundation under harmonic torque, the torsional vibrations of an embedded cylindrical foundation are presented. Besides, the angular amplitude of the foundation, the equivalent stiffness and damping coefficients of the soil are expressed explicitly. Selected examples are presented to investigate the influence of relevant parameters on the torsional vibrations.

Keywords embedded foundation saturated soil rigid foundation elastic foundation torsional vibration

Corresponding Author(s): Dazhi WU

Online First Date: 16 June 2015 Issue Date: 30 June 2015

Cite this article:

Dazhi WU,Lu YU. Torsional vibrations of a cylindrical foundation embedded in a saturated poroelastic half-space[J]. Front. Struct. Civ. Eng., 2015, 9(2): 194-202.

URL:

https://academic.hep.com.cn/fsce/EN/10.1007/s11709-015-0292-z
https://academic.hep.com.cn/fsce/EN/Y2015/V9/I2/194

Fig.1 Description of the model and coordinate system

Tab.1 Parameters of saturated soil

Fig.2 Torsional angular amplitude of a foundation embedded in single-phase medium

Fig.3 Curves of equivalent stiffness ratio with ? = 0.05 . (a) Various dimensionless frequency; (b) various embedment depth

Fig.4 Curves of equivalent damping ratio with ? = 0.05 . (a) Various dimensionless frequency; (b) various embedment depth

Fig.5 Curves of equivalent stiffness ratio and equivalent damping ratio for various ? with h ˉ = 0.5 . (a) Equivalent stiffness ratio; (b) equivalent damping ratio

Fig.6 Torsional angular amplitude of the embedded foundation with I ˉ T = 5.0 , ? = 0.05

Fig.7 Comparison of the torsional angular amplitude of the embedded rigid foundation with I ˉ T = 5.0

Fig.8 Lag phase angle curves of the embedded elastic foundation. (a) Various I ˉ T ( h ˉ = 0.5 , ? = 0.05 ); (b) various h ˉ ( I ˉ T = 5.0 , ? = 0.05 ); (c) various ? ( I ˉ T = 5.0 , h ˉ = 0.5 )

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