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Xuanming Ding - One of the best experts on this subject based on the ideXlab platform.

  • Coupled vibration of a concrete Pipe Pile with saturated soil due to longitudinal loading
    Journal of Vibroengineering, 2020
    Co-Authors: Changjie Zheng, Xuanming Ding, Shuhong An
    Abstract:

    This paper considers the longitudinal coupled vibration of an elastic bearing concrete Pipe Pile with the saturated soil. The outer and inner saturated soil are governed by the dynamic consolidation theory originally presented by Biot. The governing equations of soil are transferred to ordinary differential equations by Laplace transform. The volumetric strain and pore pressure of soil are obtained by directly solving the coupling equations of soil without introducing potential functions. The analytical expressions of the displacements and shear stresses of the soil are then obtained. The Pile response is derived on the basis of 1D elastic theory and the perfect contacts between the Pile and soils. The displacement and velocity of the Pile in time domain are obtained by using numerical inverse transformation. Selected numerical results are presented to portray the influence of the existences of soils, Pile geometry and dynamic permeability coefficients of soils on the vibration characteristics of the Pipe Pile. At last, the displacement response between a Pipe Pile and solid Pile are compared.

  • Torsional vibration of a Pipe Pile in transversely isotropic saturated soil
    Earthquake Engineering and Engineering Vibration, 2016
    Co-Authors: Changjie Zheng, Xuanming Ding
    Abstract:

    This study considers the torsional vibration of a Pipe Pile in a transversely isotropic saturated soil layer. Based on Biot’s poroelastic theory and the constitutive relations of the transversely isotropic medium, the dynamic governing equations of the outer and inner transversely isotropic saturated soil layers are derived. The Laplace transform is used to solve the governing equations of the outer and inner soil layers. The dynamic torsional response of the Pipe Pile in the frequency domain is derived utilizing 1D elastic theory and the continuous conditions at the interfaces between the Pipe Pile and the soils. The time domain solution is obtained by Fourier inverse transform. A parametric study is conducted to demonstrate the influence of the anisotropies of the outer and inner soil on the torsional dynamic response of the Pipe Pile.

  • Lateral dynamic response of a Pipe Pile in saturated soil layer
    International Journal for Numerical and Analytical Methods in Geomechanics, 2015
    Co-Authors: Changjie Zheng, Xuanming Ding
    Abstract:

    An analytical solution is developed in this paper to investigate the vertical time-harmonic response of a Pipe Pile embedded in a viscoelastic saturated soil layer. The wave propagation in the saturated soil is simulated by Biot’s 3D poroelastic theory and that in the Pipe Pile is simulated by 1D elastodynamic theory. Potential functions are applied to decouple the governing equations of the soil. The analytical solutions of the outer and inner soil in frequency domain are obtained by the method of separation of variables. The vertical response of the Pipe Pile is then obtained based on the continuity assumption of the displacement and stress between the Pipe Pile and both the outer and inner soil. The solution is compared with existing solutions to verify the validity. Numerical examples are presented to analyze the vibration characteristics of the Pile. 2014 Published by Elsevier Ltd.

  • Vertical dynamic response of a Pipe Pile in saturated soil layer
    Computers and Geotechnics, 2014
    Co-Authors: Changjie Zheng, Xuanming Ding
    Abstract:

    Abstract An analytical solution is developed in this paper to investigate the vertical time-harmonic response of a Pipe Pile embedded in a viscoelastic saturated soil layer. The wave propagation in the saturated soil is simulated by Biot’s 3D poroelastic theory and that in the Pipe Pile is simulated by 1D elastodynamic theory. Potential functions are applied to decouple the governing equations of the soil. The analytical solutions of the outer and inner soil in frequency domain are obtained by the method of separation of variables. The vertical response of the Pipe Pile is then obtained based on the continuity assumption of the displacement and stress between the Pipe Pile and both the outer and inner soil. The solution is compared with existing solutions to verify the validity. Numerical examples are presented to analyze the vibration characteristics of the Pile.

  • wave propagation in a Pipe Pile for low strain integrity testing
    Journal of Engineering Mechanics-asce, 2011
    Co-Authors: Xuanming Ding, Yumin Chen
    Abstract:

    This paper presents an analytical solution methodology for a tubular structure subjected to a transient point loading in low-strain integrity testing. The three-dimensional effects on the Pile head and the applicability of plane-section assumption are the main problems in low-strain integrity testing on a large-diameter tubular structure, such as a Pipe Pile. The propagation of stress waves in a tubular structure cannot be expressed by one-dimensional wave theory on the basis of plane-section assumption. This paper establishes the computational model of a large-diameter tubular structure with a variable wave impedance section, where the soil resistance is simulated by the Winkler model, and the exciting force is simulated with semisinusoidal impulse. The defects are classified into the change in the wall thickness and Young’s modulus. Combining the boundary and initial conditions, a frequency-domain analytical solution of a three-dimensional wave equation is deduced from the Fourier transform method and the separation of variables methods. On the basis of the frequency-domain analytic solution, the time-domain response is obtained from the inverse Fourier transform method. The three-dimensional finite-element models are used to verify the validity of analytical solutions for both an intact and a defective Pipe Pile. The analytical solutions obtained from frequency domain are compared with the finite-element method (FEM) results on both Pipe Piles in this paper, including the velocity time history, peak value, incident time arrival, and reflected wave crests. A case study is shown and the characteristics of velocity response time history on the top of an intact and a defective Pile are investigated. The comparisons show that the analytical solution derived in this paper is reliable for application in the integrity testing on a tubular structure.

Changjie Zheng - One of the best experts on this subject based on the ideXlab platform.

  • Coupled vibration of a concrete Pipe Pile with saturated soil due to longitudinal loading
    Journal of Vibroengineering, 2020
    Co-Authors: Changjie Zheng, Xuanming Ding, Shuhong An
    Abstract:

    This paper considers the longitudinal coupled vibration of an elastic bearing concrete Pipe Pile with the saturated soil. The outer and inner saturated soil are governed by the dynamic consolidation theory originally presented by Biot. The governing equations of soil are transferred to ordinary differential equations by Laplace transform. The volumetric strain and pore pressure of soil are obtained by directly solving the coupling equations of soil without introducing potential functions. The analytical expressions of the displacements and shear stresses of the soil are then obtained. The Pile response is derived on the basis of 1D elastic theory and the perfect contacts between the Pile and soils. The displacement and velocity of the Pile in time domain are obtained by using numerical inverse transformation. Selected numerical results are presented to portray the influence of the existences of soils, Pile geometry and dynamic permeability coefficients of soils on the vibration characteristics of the Pipe Pile. At last, the displacement response between a Pipe Pile and solid Pile are compared.

  • Torsional vibration of a Pipe Pile in transversely isotropic saturated soil
    Earthquake Engineering and Engineering Vibration, 2016
    Co-Authors: Changjie Zheng, Xuanming Ding
    Abstract:

    This study considers the torsional vibration of a Pipe Pile in a transversely isotropic saturated soil layer. Based on Biot’s poroelastic theory and the constitutive relations of the transversely isotropic medium, the dynamic governing equations of the outer and inner transversely isotropic saturated soil layers are derived. The Laplace transform is used to solve the governing equations of the outer and inner soil layers. The dynamic torsional response of the Pipe Pile in the frequency domain is derived utilizing 1D elastic theory and the continuous conditions at the interfaces between the Pipe Pile and the soils. The time domain solution is obtained by Fourier inverse transform. A parametric study is conducted to demonstrate the influence of the anisotropies of the outer and inner soil on the torsional dynamic response of the Pipe Pile.

  • Lateral dynamic response of a Pipe Pile in saturated soil layer
    International Journal for Numerical and Analytical Methods in Geomechanics, 2015
    Co-Authors: Changjie Zheng, Xuanming Ding
    Abstract:

    An analytical solution is developed in this paper to investigate the vertical time-harmonic response of a Pipe Pile embedded in a viscoelastic saturated soil layer. The wave propagation in the saturated soil is simulated by Biot’s 3D poroelastic theory and that in the Pipe Pile is simulated by 1D elastodynamic theory. Potential functions are applied to decouple the governing equations of the soil. The analytical solutions of the outer and inner soil in frequency domain are obtained by the method of separation of variables. The vertical response of the Pipe Pile is then obtained based on the continuity assumption of the displacement and stress between the Pipe Pile and both the outer and inner soil. The solution is compared with existing solutions to verify the validity. Numerical examples are presented to analyze the vibration characteristics of the Pile. 2014 Published by Elsevier Ltd.

  • Vertical dynamic response of a Pipe Pile in saturated soil layer
    Computers and Geotechnics, 2014
    Co-Authors: Changjie Zheng, Xuanming Ding
    Abstract:

    Abstract An analytical solution is developed in this paper to investigate the vertical time-harmonic response of a Pipe Pile embedded in a viscoelastic saturated soil layer. The wave propagation in the saturated soil is simulated by Biot’s 3D poroelastic theory and that in the Pipe Pile is simulated by 1D elastodynamic theory. Potential functions are applied to decouple the governing equations of the soil. The analytical solutions of the outer and inner soil in frequency domain are obtained by the method of separation of variables. The vertical response of the Pipe Pile is then obtained based on the continuity assumption of the displacement and stress between the Pipe Pile and both the outer and inner soil. The solution is compared with existing solutions to verify the validity. Numerical examples are presented to analyze the vibration characteristics of the Pile.

Yi Guan - One of the best experts on this subject based on the ideXlab platform.

  • numerical simulation of soil squeezing effects of a jacked Pipe Pile in soft foundation soil and in foundation soil with an underlying gravel layer
    Geotechnical and Geological Engineering, 2016
    Co-Authors: Yan Shao, Shichuan Wang, Yi Guan
    Abstract:

    A three-dimensional finite-element analysis was carried out using ABAQUS to evaluate the squeezing effects of a prestressed high-strength concrete (PHC) Pipe Pile, including land upheaval, lateral soil displacement, and soil stress field with depth-varying during Pile-sinking. Field data used in the analysis were obtained from the settlement building project in Hefei City, Anhui Province, China. In coastal areas of China, PHC Pipe Piles are normally used for reinforcement of soft foundation. The changes of displacement with the increase of soil depth and radial distance during Pile-sinking are simulated for both soft foundation and soft clay with an underlying gravel layer. The numerical simulation results show that there is little difference in land upheaval with soil depth during Pile-sinking, and the obvious land upheaval occurs within 0.8 m from the center of the Pile. The lateral soil displacement is evident within the area of 1.0 m from the axis of the PHC, decreases with the increase of radial distance during Pile-sinking, and becomes negligible beyond 4.0 m. The existence of the gravel layer helps reduce soil squeezing substantially, and the soil squeezing effects during Pile-sinking have less influence on the surrounding area of foundation with a gravel layer than that in a soft foundation soil without gravel layer.

Yan Qi-fang - One of the best experts on this subject based on the ideXlab platform.

  • Study on Lateral Dynamic Impedance of Pipe Pile Considering Soil-Pile Dynamic Interaction
    Journal of Henan University, 2020
    Co-Authors: Yan Qi-fang
    Abstract:

    The horizontal vibration of soil is solved by potential function based on the theory of wave propagation and plane strain assumptions,and the horizontal dynamic action of the around Pile soil and inner soil on Pipe Pile is obtained.The horizontal vibration of Pipe Pile is investigated with initial parameter method,and the influences of shear modulus ratio and outer radius on the horizontal dynamic impedance of Pipe Pile is investigated.

  • Vertical vibration characteristics of Pipe Pile in saturated soil
    Journal of Hydraulic Engineering, 2020
    Co-Authors: Yan Qi-fang
    Abstract:

    There are important differences in the mechanical properties,especially dynamic behaviors of a Pile in saturated soil and single-phase soil,because of the flow quality of pore water in saturated soil and the different permeability of the soil and the Pile.The soil around the Pile is regarded as saturated porous medium,and the macro-mechanical properties of saturated soil is described by the theory of porous medium.Appling the Novak plane assumption to saturated soil,the Novak plane strain model was spread to Pipe Pile in saturated soil,and the vertical vibration of soil layer was solved;the vertical vibration of Pipe Pile in saturated soil was analyzed,and the influences of mechanical parameters of soil around the Pile and inner soil on the vibration were investigated.The results indicate that the changes of complex stiffness and admittance of Pipe Pile with frequency are different with solid Pile;the soil around the Pile has a greater influence than the inner soil,and the frictional resistance of outer soil is larger than that of the inner soil.

Jingpei Li - One of the best experts on this subject based on the ideXlab platform.

  • service life prediction of cracked rc Pipe Piles exposed to marine environments
    Construction and Building Materials, 2014
    Co-Authors: Wei Shao, Jingpei Li
    Abstract:

    Abstract Cracks due to shrinkage, chemical reactions and weathering process occur unavoidably during construction and application of RC Pipe Piles. These cracks may be the main pathways through which chloride diffuses into the concrete and also can be one of the major reasons of steel corrosion in RC Pipe Piles exposed to marine environments. In the present paper, an analytical method for predicting the service life of cracked RC Pipe Pile with considering the effect of cracks on the chloride diffusion is presented. The governing equation of chloride diffusion into RC Pipe Pile is described and solved analytically by using the Bessel functions. The equivalent chloride diffusion coefficient is derived based on the partition of chloride diffusion through cracked RC Pipe Pile. The threshold chloride content is estimated from a wide review of previous experimental studies. Comparisons of analytical results with experimental data are conducted to establish the validity of the proposed analytical method. Furthermore, an application of the analytical method is demonstrated by predicting service life of cracked RC Pipe Piles exposed to marine environments. The analysis results demonstrate the importance of considering the effect of cracks for accurate prediction of service life in RC Pipe Piles exposed to marine environments.