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Rihong Zhang - One of the best experts on this subject based on the ideXlab platform.

  • model tests comparing the behavior of pre bored grouted planted piles and a wished in place concrete pile in Dense Sand
    Soils and Foundations, 2019
    Co-Authors: Jiajin Zhou, Xiaonan Gong, Rihong Zhang
    Abstract:

    Abstract The compressive bearing capacity of wished-in-place (WIP) concrete piles and pre-bored grouted planted (PGP) piles in Dense Sand was investigated by means of model tests. In total, three model piles were tested. The load–displacement response, axial force and tip resistance of each model pile were measured in the static load test process. Several conclusions can be drawn from the model test results: the pre-bored grouted planted nodular (PGPN) pile and the pre-bored grouted planted pipe (PGPP) pile have ultimate skin friction 1.23–1.36 times and 1.34–1.46 times greater than the ultimate skin friction of the wished-in-place (WIP) pile, respectively. The tip bearing capacity of the PGP pile is similar to the tip bearing capacity of the WIP pile, and the hyperbolic model of normalized tip resistance (qb/qc) and normalized tip displacement (Sb/D) can represent the tip load–displacement response of the WIP and PGP piles well.

  • shaft capacity of the pre bored grouted planted pile in Dense Sand
    Acta Geotechnica, 2018
    Co-Authors: Jiajin Zhou, Xiaonan Gong, Kuihua Wang, Rihong Zhang
    Abstract:

    The pre-bored grouted planted pile is a new type of composite pile foundation that consists of a precast concrete pile and the surrounding cemented soil. A series of shear tests were conducted in a specific shear test apparatus to investigate the shaft capacity of the different pile–soil interfaces. The test results show that the frictional capacity of the cemented soil–Sand interface is controlled mainly by the Sand properties, while the strength of the cemented soil slightly influences the interface properties by affecting the normalized roughness coefficient Rn. The frictional capacity of the concrete–Sand interface is similar to the frictional capacity of the cemented soil–Sand interface, and the existence of mud cake layer virtually hampers the frictional properties of the interface. The maximum skin friction of the concrete–cemented soil interface increases approximately linearly with the increasing cemented soil strength, and the value of the maximum skin friction is much larger than that of the cemented soil–Sand interface of identical cemented soil strength, which demonstrates the integrity of the pre-bored grouted planted pile in the load transfer process.

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

  • model tests comparing the behavior of pre bored grouted planted piles and a wished in place concrete pile in Dense Sand
    Soils and Foundations, 2019
    Co-Authors: Jiajin Zhou, Xiaonan Gong, Rihong Zhang
    Abstract:

    Abstract The compressive bearing capacity of wished-in-place (WIP) concrete piles and pre-bored grouted planted (PGP) piles in Dense Sand was investigated by means of model tests. In total, three model piles were tested. The load–displacement response, axial force and tip resistance of each model pile were measured in the static load test process. Several conclusions can be drawn from the model test results: the pre-bored grouted planted nodular (PGPN) pile and the pre-bored grouted planted pipe (PGPP) pile have ultimate skin friction 1.23–1.36 times and 1.34–1.46 times greater than the ultimate skin friction of the wished-in-place (WIP) pile, respectively. The tip bearing capacity of the PGP pile is similar to the tip bearing capacity of the WIP pile, and the hyperbolic model of normalized tip resistance (qb/qc) and normalized tip displacement (Sb/D) can represent the tip load–displacement response of the WIP and PGP piles well.

  • shaft capacity of the pre bored grouted planted pile in Dense Sand
    Acta Geotechnica, 2018
    Co-Authors: Jiajin Zhou, Xiaonan Gong, Kuihua Wang, Rihong Zhang
    Abstract:

    The pre-bored grouted planted pile is a new type of composite pile foundation that consists of a precast concrete pile and the surrounding cemented soil. A series of shear tests were conducted in a specific shear test apparatus to investigate the shaft capacity of the different pile–soil interfaces. The test results show that the frictional capacity of the cemented soil–Sand interface is controlled mainly by the Sand properties, while the strength of the cemented soil slightly influences the interface properties by affecting the normalized roughness coefficient Rn. The frictional capacity of the concrete–Sand interface is similar to the frictional capacity of the cemented soil–Sand interface, and the existence of mud cake layer virtually hampers the frictional properties of the interface. The maximum skin friction of the concrete–cemented soil interface increases approximately linearly with the increasing cemented soil strength, and the value of the maximum skin friction is much larger than that of the cemented soil–Sand interface of identical cemented soil strength, which demonstrates the integrity of the pre-bored grouted planted pile in the load transfer process.

Kshama Roy - One of the best experts on this subject based on the ideXlab platform.

  • upward pipe soil interaction for shallowly buried pipelines in Dense Sand
    Journal of Geotechnical and Geoenvironmental Engineering, 2018
    Co-Authors: Kshama Roy, Bipul Hawlader, Shawn Kenny, Ian D. Moore
    Abstract:

    AbstractUplift resistance is a key parameter against upheaval buckling in the design of a buried pipeline. The mobilization of uplift resistance in Dense Sand is investigated in the present study b...

  • lateral resistance of pipes and strip anchors buried in Dense Sand
    Canadian Geotechnical Journal, 2018
    Co-Authors: Kshama Roy, Bipul Hawlader, Shawn Kenny, Ian D. Moore
    Abstract:

    The response of buried pipes and vertical strip anchors in Dense Sand under lateral loading is compared based on finite-element (FE) modeling. Incorporating strain-softening behaviour of Dense Sand...

  • finite element modeling of lateral pipeline soil interactions in Dense Sand
    Canadian Geotechnical Journal, 2016
    Co-Authors: Kshama Roy, Bipul Hawlader, Shawn Kenny, Ian D. Moore
    Abstract:

    Finite element (FE) analyses of pipeline–soil interaction for pipelines buried in Dense Sand subjected to lateral ground displacements are presented in this paper. Analysis is performed — using the...

  • effects of post peak softening behavior of Dense Sand on lateral and upward displacement of buried pipelines
    ASME 2015 34th International Conference on Ocean Offshore and Arctic Engineering, 2015
    Co-Authors: Kshama Roy, Bipul Hawlader, Shawn Kenny, Ian D. Moore
    Abstract:

    Buried pipelines are extensively used in onshore and offshore for transportation of hydrocarbons. The response of pipeline due to lateral and upward relative displacements is one of the major concerns in pipeline design. Both physical modeling and numerical analyses have been performed in the past to understand pipeline-soil interaction mechanisms. The numerical analyses are generally performed using finite element (FE) modeling techniques. For the pipelines buried in Sand, a large number of analyses available in the literature have been performed using the Mohr-Coulomb model assigning constant values of angle of internal friction (ϕ′) and dilation (ψ). However, Dense Sand shows post-peak softening behavior and the behavior of Sand also depends on mode of shearing, such as triaxial (TX), direct shear (DS) or direct simple shear (DSS) conditions. In the present study, FE analysis of buried pipelines in Dense Sand is presented. The first set of analyses are performed using the built-in Mohr-Coulomb model in Abaqus FE software with constant angles of internal friction and dilation, as typically used in previous FE analysis of pipeline-soil interaction. The second set of analyses are performed using a modified Mohr-Coulomb model where pre-peak hardening, post-peak softening, density and confining pressure dependent friction and dilation angles are considered. The FE analyses are performed using the Arbitrary Lagrangian-Eulerian (ALE) approach available in Abaqus/Explicit FE software. The modified Mohr-Coulomb model is implemented in Abaqus FE software using a user defined subroutine. Shear band formation due to strain localization and failure patterns for both lateral and upward pipeline-soil interactions are discussed from the simulations with MC and MMC models. FE results show that the MMC model can simulate the load-displacement behavior and failure pattern better than the simulations with the MC model.Copyright © 2015 by ASME

  • finite element modeling of large diameter monopiles in Dense Sand for offshore wind turbine foundations
    ASME 2015 34th International Conference on Ocean Offshore and Arctic Engineering, 2015
    Co-Authors: Sheikh Sharif Ahmed, Bipul Hawlader, Kshama Roy
    Abstract:

    With increasing demand of energy, attention to the alternative sources of sustainable energy is getting priority over the last decades. Offshore wind turbine is one of them. The most widely used foundation system for the wind turbine is the monopile, which is a large diameter single pile. In the present study, three-dimensional finite element (FE) analyses are performed to evaluate the capacity of large diameter monopiles in Dense Sand using the Arbitrary Lagrangian-Eulerian (ALE) approach available in Abaqus/Explicit FE software. The behavior of Sand is modeled using the Mohr-Coulomb (MC) and a modified Mohr-Coulomb (MMC) model where the pre-peak hardening, post-peak softening and the effects of mean effective stress and relative density on stress-strain behavior of Dense Sand are considered. Comparison with physical model test results shows that the MMC model can simulate better the load-displacement response than that with the MC model. The mechanisms involved in soil deformation are also explained using FE results.Copyright © 2015 by ASME

Ian D. Moore - One of the best experts on this subject based on the ideXlab platform.

  • upward pipe soil interaction for shallowly buried pipelines in Dense Sand
    Journal of Geotechnical and Geoenvironmental Engineering, 2018
    Co-Authors: Kshama Roy, Bipul Hawlader, Shawn Kenny, Ian D. Moore
    Abstract:

    AbstractUplift resistance is a key parameter against upheaval buckling in the design of a buried pipeline. The mobilization of uplift resistance in Dense Sand is investigated in the present study b...

  • lateral resistance of pipes and strip anchors buried in Dense Sand
    Canadian Geotechnical Journal, 2018
    Co-Authors: Kshama Roy, Bipul Hawlader, Shawn Kenny, Ian D. Moore
    Abstract:

    The response of buried pipes and vertical strip anchors in Dense Sand under lateral loading is compared based on finite-element (FE) modeling. Incorporating strain-softening behaviour of Dense Sand...

  • finite element modeling of lateral pipeline soil interactions in Dense Sand
    Canadian Geotechnical Journal, 2016
    Co-Authors: Kshama Roy, Bipul Hawlader, Shawn Kenny, Ian D. Moore
    Abstract:

    Finite element (FE) analyses of pipeline–soil interaction for pipelines buried in Dense Sand subjected to lateral ground displacements are presented in this paper. Analysis is performed — using the...

  • effects of post peak softening behavior of Dense Sand on lateral and upward displacement of buried pipelines
    ASME 2015 34th International Conference on Ocean Offshore and Arctic Engineering, 2015
    Co-Authors: Kshama Roy, Bipul Hawlader, Shawn Kenny, Ian D. Moore
    Abstract:

    Buried pipelines are extensively used in onshore and offshore for transportation of hydrocarbons. The response of pipeline due to lateral and upward relative displacements is one of the major concerns in pipeline design. Both physical modeling and numerical analyses have been performed in the past to understand pipeline-soil interaction mechanisms. The numerical analyses are generally performed using finite element (FE) modeling techniques. For the pipelines buried in Sand, a large number of analyses available in the literature have been performed using the Mohr-Coulomb model assigning constant values of angle of internal friction (ϕ′) and dilation (ψ). However, Dense Sand shows post-peak softening behavior and the behavior of Sand also depends on mode of shearing, such as triaxial (TX), direct shear (DS) or direct simple shear (DSS) conditions. In the present study, FE analysis of buried pipelines in Dense Sand is presented. The first set of analyses are performed using the built-in Mohr-Coulomb model in Abaqus FE software with constant angles of internal friction and dilation, as typically used in previous FE analysis of pipeline-soil interaction. The second set of analyses are performed using a modified Mohr-Coulomb model where pre-peak hardening, post-peak softening, density and confining pressure dependent friction and dilation angles are considered. The FE analyses are performed using the Arbitrary Lagrangian-Eulerian (ALE) approach available in Abaqus/Explicit FE software. The modified Mohr-Coulomb model is implemented in Abaqus FE software using a user defined subroutine. Shear band formation due to strain localization and failure patterns for both lateral and upward pipeline-soil interactions are discussed from the simulations with MC and MMC models. FE results show that the MMC model can simulate the load-displacement behavior and failure pattern better than the simulations with the MC model.Copyright © 2015 by ASME

  • experimental investigation of longitudinal bending of buried steel pipes pulled through Dense Sand
    Journal of Pipeline Systems Engineering and Practice, 2014
    Co-Authors: Mohamed Almahakeri, Amir Fam, Ian D. Moore
    Abstract:

    AbstractNorth America is traversed by many high-pressure oil and gas transmission pipes and the stability of that essential buried infrastructure must be maintained under a variety of earth-loading conditions. In the research reported in this paper, a series of pipe-bending experiments have been conducted on 105-mm (4.1-in.) outside diameter and 1,830-mm (6-ft) long steel pipes buried in Dense Sand placed in a 4,000×2,000×2,000-mm (157.5×78.7×74.7-in.) test pit. The pipe ends were pulled by two parallel cables attached to a spreader beam outside the test region, which was pulled by a hydraulic actuator. The research reported in this paper investigated burial depth-to-diameter ratios of 3, 5, and 7 as well as two horizontal extents for the soil behind the pipe distances of 3D and 9.5D. Special consideration was made to assess the influence of friction between the pulling-cables and soil. This friction is significant and may contribute about 20% of the maximum pulling load for the case of a depth-to-diamete...

Xiaonan Gong - One of the best experts on this subject based on the ideXlab platform.

  • model tests comparing the behavior of pre bored grouted planted piles and a wished in place concrete pile in Dense Sand
    Soils and Foundations, 2019
    Co-Authors: Jiajin Zhou, Xiaonan Gong, Rihong Zhang
    Abstract:

    Abstract The compressive bearing capacity of wished-in-place (WIP) concrete piles and pre-bored grouted planted (PGP) piles in Dense Sand was investigated by means of model tests. In total, three model piles were tested. The load–displacement response, axial force and tip resistance of each model pile were measured in the static load test process. Several conclusions can be drawn from the model test results: the pre-bored grouted planted nodular (PGPN) pile and the pre-bored grouted planted pipe (PGPP) pile have ultimate skin friction 1.23–1.36 times and 1.34–1.46 times greater than the ultimate skin friction of the wished-in-place (WIP) pile, respectively. The tip bearing capacity of the PGP pile is similar to the tip bearing capacity of the WIP pile, and the hyperbolic model of normalized tip resistance (qb/qc) and normalized tip displacement (Sb/D) can represent the tip load–displacement response of the WIP and PGP piles well.

  • shaft capacity of the pre bored grouted planted pile in Dense Sand
    Acta Geotechnica, 2018
    Co-Authors: Jiajin Zhou, Xiaonan Gong, Kuihua Wang, Rihong Zhang
    Abstract:

    The pre-bored grouted planted pile is a new type of composite pile foundation that consists of a precast concrete pile and the surrounding cemented soil. A series of shear tests were conducted in a specific shear test apparatus to investigate the shaft capacity of the different pile–soil interfaces. The test results show that the frictional capacity of the cemented soil–Sand interface is controlled mainly by the Sand properties, while the strength of the cemented soil slightly influences the interface properties by affecting the normalized roughness coefficient Rn. The frictional capacity of the concrete–Sand interface is similar to the frictional capacity of the cemented soil–Sand interface, and the existence of mud cake layer virtually hampers the frictional properties of the interface. The maximum skin friction of the concrete–cemented soil interface increases approximately linearly with the increasing cemented soil strength, and the value of the maximum skin friction is much larger than that of the cemented soil–Sand interface of identical cemented soil strength, which demonstrates the integrity of the pre-bored grouted planted pile in the load transfer process.