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Jinchun Chai - One of the best experts on this subject based on the ideXlab platform.

  • influence of geosynthetic reinforcement on the progressive failure of rigid columns under an Embankment Load
    Acta Geotechnica, 2021
    Co-Authors: Gang Zheng, Haizuo Zhou, Jinchun Chai
    Abstract:

    Prior investigations have revealed that the stress characteristics of columns at different locations beneath an Embankment vary. A failed column releases stress and causes significant increases in the stresses within neighbouring columns, possibly leading to progressive failure of adjacent columns and global failure of the Embankment. Prior studies have presented insights into the progressive failure of column-supported Embankments. However, limited insight has been provided into the progressive failure mechanism of geosynthetic-reinforced and rigid column-supported Embankments. In this technical note, the effects of geosynthetic reinforcement on progressive failure are numerically analysed. A comparison of the progressive failure of rigid columns with and without geosynthetic reinforcement is first conducted. The restraining effects of geosynthetics on progressive failure of the columns and the influence of geosynthetic tensile stiffness on Embankment stability are analysed. The results reveal that progressive failure is primarily governed by the distribution of the bending moment and the axial force within the columns. To further investigate the contribution of geosynthetics to resisting progressive failure of rigid columns, the internal forces in the columns and tensile strains in the geosynthetics are discussed.

  • numerical modeling of progressive failure of rigid piles under Embankment Load
    Canadian Geotechnical Journal, 2019
    Co-Authors: Gang Zheng, Xinyu Yang, Haizuo Zhou, Jinchun Chai
    Abstract:

    Rigid piles (e.g., concrete piles) have been widely used to improve soft clay for the rapid construction of Embankments. In this study, a damage plasticity model that considers the brittle failure ...

  • 3D FEM investigation on bending failure mechanism of column inclusion under Embankment Load
    Lowland Technology International, 2015
    Co-Authors: Sailesh Shrestha, Dennis T. Bergado, Jinchun Chai, T. Hino, Y. Kamo
    Abstract:

    Bending failure mechanism of column inclusions in soft clay deposit under Embankment Loading has been investigated by three dimensional (3D) finite element analyses. Firstly the effectiveness of the numerical procedure has been verified by comparing the simulated and the measured results of a centrifuge model test reported in the literature in terms of lateral displacement, settlement, and the bending moment in the column. Then the effects of the size of the column improved area from the toe toward the center of the Embankment, stiffness of the column, the length of the column on the maximum bending moment in the column have been investigated numerically. The numerical results indicate that increase the size of the improved area, reduced the bending moment in the upper part (near ground surface) of the column; increase the stiffness of the column increased the maximum bending moment; and the maximum bending moment occurred at the end of the column in the case of an end bearing column, and in the upper part of the column for a floating column. The numerical results also indicate that when the whole area under the Embankment is improved by end bearing columns with an area improvement ratio of 28 % and tensile strength of the column of 100 kN/m2, the Embankment Load can be applied with a factor of safety of about 2 for bending failure of the columns is about 13 times of the initial undrained shear strength of the soft deposit.

  • PreLoading clayey deposit by vacuum pressure with cap-drain: Analyses versus performance
    Geotextiles and Geomembranes, 2008
    Co-Authors: Jinchun Chai, Norihiko Miura, Dennis T. Bergado
    Abstract:

    Abstract A method of improving soft clayey deposit by combining cap-drain (CPVD) with vacuum pressure is described. The method uses a surface or subsurface soil layer as a sealing layer with no need to place an air-tightening sheet on the ground surface. It is explained that the method has advantages for the following situations: (a) a higher air/water permeability layer at ground surface and (b) combining vacuum pressure with Embankment Load. A case history of consolidating a reclaimed clayey deposit by combining CPVD with vacuum pressure is analyzed and discussed. The site was in an under-consolidated state before starting the project. It is shown that the method is effective, and the method proposed by Chai et al. [Ground deformation induced by vacuum consolidation. Journal of Geotechnical and Geoenvironmental Engineering, ASCE 131(12), 1552–1561] for calculating the vacuum-pressure-induced ground deformation is useful for the design of the vacuum consolidation project. The back-calculation shows that for this under-consolidated deposit, vacuum pressure caused plane strain type isotropic deformation near the ground surface.

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

  • influence of geosynthetic reinforcement on the progressive failure of rigid columns under an Embankment Load
    Acta Geotechnica, 2021
    Co-Authors: Gang Zheng, Haizuo Zhou, Jinchun Chai
    Abstract:

    Prior investigations have revealed that the stress characteristics of columns at different locations beneath an Embankment vary. A failed column releases stress and causes significant increases in the stresses within neighbouring columns, possibly leading to progressive failure of adjacent columns and global failure of the Embankment. Prior studies have presented insights into the progressive failure of column-supported Embankments. However, limited insight has been provided into the progressive failure mechanism of geosynthetic-reinforced and rigid column-supported Embankments. In this technical note, the effects of geosynthetic reinforcement on progressive failure are numerically analysed. A comparison of the progressive failure of rigid columns with and without geosynthetic reinforcement is first conducted. The restraining effects of geosynthetics on progressive failure of the columns and the influence of geosynthetic tensile stiffness on Embankment stability are analysed. The results reveal that progressive failure is primarily governed by the distribution of the bending moment and the axial force within the columns. To further investigate the contribution of geosynthetics to resisting progressive failure of rigid columns, the internal forces in the columns and tensile strains in the geosynthetics are discussed.

  • numerical modeling of progressive failure of rigid piles under Embankment Load
    Canadian Geotechnical Journal, 2019
    Co-Authors: Gang Zheng, Xinyu Yang, Haizuo Zhou, Jinchun Chai
    Abstract:

    Rigid piles (e.g., concrete piles) have been widely used to improve soft clay for the rapid construction of Embankments. In this study, a damage plasticity model that considers the brittle failure ...

Jianhua Yin - One of the best experts on this subject based on the ideXlab platform.

  • numerical study of creep effects on settlements and Load transfer mechanisms of soft soil improved by deep cement mixed soil columns under Embankment Load
    Geotextiles and Geomembranes, 2020
    Co-Authors: Wei Qiang Feng, Jianhua Yin
    Abstract:

    Abstract Deep cement mixed (DCM) soil columns have been widely utilized to improve soft soil to support Embankments or seawalls. However, the influence of the time-dependent behavior of the soft soil on the performance of DCM column-supported Embankments is not well understood. In this study, the finite element (FE) model was established to investigate the creep effects on settlements and Load transfer mechanisms of the soft soil improved by DCM columns under Embankment Load. Comparisons were conducted for the cases of the soft soil with or without creep. The parametric analysis demonstrated that the area replacement ratio and Young's modulus of the DCM column can largely influence the long-term behaviors of the DCM column-improved composite ground. The numerical results were also compared with the results calculated by German design method (EBGEO) and British design method (BS 8006). Regarding the vertical stress taken by the DCM column, EBGEO method provides a lower limit while BS 8006 method provides an upper limit.

Panich Voottipruex - One of the best experts on this subject based on the ideXlab platform.

  • Comparative performances of two- and three-dimensional analyses of soil-cement mixing columns under an Embankment Load
    Marine Georesources & Geotechnology, 2018
    Co-Authors: Pitthaya Jamsawang, Panich Voottipruex, Ekkarin Phongphinittana, Pornkasem Jongpradist
    Abstract:

    AbstractThis research presents measurements and simulations of the full-scale behavior of a test Embankment built on a soft marine clay deposit improved using soil–cement mixing (SCM) columns in Ba...

  • three dimensional numerical analysis of a dcm column supported highway Embankment
    Computers and Geotechnics, 2016
    Co-Authors: Pitthaya Jamsawang, Panich Voottipruex, Naphol Yoobanpot, Nuttawut Thanasisathit, Pornkasem Jongpradist
    Abstract:

    Abstract This paper presents a three-dimensional numerical analysis of a well-monitored DCM (deep cement mixing) column-supported Embankment for a highway in Thailand. A coupled three-dimensional mechanical and hydraulic numerical model was used for this analysis, and the results are compared with the field measurements, including settlement, Load distribution between soil and DCM columns, excess pore water pressure and lateral movement. The numerical model reasonably simulated the performance of the DCM column-supported Embankment compared to the observed data. From the field measurements, the surrounding soils carried approximately half an Embankment Load, while the rest was transferred to the stronger soil layers below. The computed maximum bending moment in the column under the toe of the Embankment was located at the interlayer between the fill material and soft clay due to the existence of thick fill material layer. A parametric study was conducted to investigate the influence of five key factors on the performance of the DCM column-supported Embankment. The parametric study indicated that the factor of safety against bending moment failure ( FS bending ) seems to be the most important factor of safety to design in this study. The embedded column was more suitable than a fixed column to support high Embankment Load due to the higher moment capacity of the column with the same improvement area ratio a r , while the reduction ratios of settlement ( R s ) and lateral movement ( R l ) were not significantly different. If the floating column is chosen, sufficient improvement depth to produce the column tip laterally restrained is necessary to not only reduce the lateral movement but also increase the FS bending . The d r of greater than 0.7 is suggested in this study.

  • behavior and simulation of deep cement mixing dcm and stiffened deep cement mixing sdcm piles under full scale Loading
    Soils and Foundations, 2011
    Co-Authors: Panich Voottipruex, Dennis T. Bergado, Pitthaya Jamsawang, T Suksawat, W Cheang
    Abstract:

    ABSTRACT A new kind of Deep Cement Mixing (DCM) pile called Stiffened Deep Mixing Pile (SDCM) is introduced to mitigate the low flexural strength and unexpected failures of DCM piles. A jet grouting method with a jet pressure of 22 MPa, was utilized in the installation of DCM piles. The SDCM pile consists of a DCM pile with a precast reinforced concrete core pile inserted at its center. Pile and Embankment Load tests were conducted, and then the results of the field Load tests were simulated by a 3D finite element method (FEM) to back-analyze and confirm the related design parameters. These parameters were then used further in numerical experiments. The field test results showed that the settlements and lateral movements of the SDCM pile using a prestressed concrete core pile with area ratio (Acore/ADCM) of 0.17 and a length ratio of 0.85 was less than those of the DCM pile by 40% and 60%, respectively. Moreover, the SDCM pile foundation increased the bearing capacity by as much as 2.2 times. The average lateral pile capacity of the SDCM piles was 15 times higher than the DCM piles. A strength reduction factor of 0.40 was obtained at the concrete core and the DCM interface from the full scale pullout test. The behavior of both the DCM and SDCM piles was confirmed from the subsequent 3D FEM simulations. From the 3D FEM simulations, the length of the concrete core pile had more influence on the settlements of the SDCM pile than its cross-sectional area. However, both the length and cross-sectional area of concrete core pile affected the lateral resistance of the SDCM pile.

Haizuo Zhou - One of the best experts on this subject based on the ideXlab platform.

  • influence of geosynthetic reinforcement on the progressive failure of rigid columns under an Embankment Load
    Acta Geotechnica, 2021
    Co-Authors: Gang Zheng, Haizuo Zhou, Jinchun Chai
    Abstract:

    Prior investigations have revealed that the stress characteristics of columns at different locations beneath an Embankment vary. A failed column releases stress and causes significant increases in the stresses within neighbouring columns, possibly leading to progressive failure of adjacent columns and global failure of the Embankment. Prior studies have presented insights into the progressive failure of column-supported Embankments. However, limited insight has been provided into the progressive failure mechanism of geosynthetic-reinforced and rigid column-supported Embankments. In this technical note, the effects of geosynthetic reinforcement on progressive failure are numerically analysed. A comparison of the progressive failure of rigid columns with and without geosynthetic reinforcement is first conducted. The restraining effects of geosynthetics on progressive failure of the columns and the influence of geosynthetic tensile stiffness on Embankment stability are analysed. The results reveal that progressive failure is primarily governed by the distribution of the bending moment and the axial force within the columns. To further investigate the contribution of geosynthetics to resisting progressive failure of rigid columns, the internal forces in the columns and tensile strains in the geosynthetics are discussed.

  • numerical modeling of progressive failure of rigid piles under Embankment Load
    Canadian Geotechnical Journal, 2019
    Co-Authors: Gang Zheng, Xinyu Yang, Haizuo Zhou, Jinchun Chai
    Abstract:

    Rigid piles (e.g., concrete piles) have been widely used to improve soft clay for the rapid construction of Embankments. In this study, a damage plasticity model that considers the brittle failure ...