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Ba-phu Nguyen - One of the best experts on this subject based on the ideXlab platform.

  • Large-strain consolidation analysis of PVD-installed soft soil considering the Discharge Capacity variation according to depth and time
    Engineering Computations, 2020
    Co-Authors: Ba-phu Nguyen, Ananta Man Singh Pradhan, Tan Hung Nguyen, Nhat-phi Doan, Van Quang Nguyen, Thanh-canh Huynh
    Abstract:

    PurposeThe consolidation behavior of prefabricated vertical drain (PVD)-installed soft deposits mainly depends on the PVD performance. The purpose of this study is to propose a numerical solution for the consolidation of PVD-installed soft soil using the large-strain theory, in which the reduction of Discharge Capacity of PVD according to depth and time is simultaneously considered.Design/methodology/approachThe proposed solution also takes into account the general constitute relationship of soft soil. Subsequently, the proposed solution is applied to analyze and compare with the monitoring data of two cases, one is the experimental test and another is the test embankment in Saga airport.FindingsThe results show that the reduction of PVD Discharge Capacity according to depth and time increased the duration required to achieve a certain degree of consolidation. The consolidation rate is more sensitive to the reduction of PVD Discharge Capacity according to time than that according to the depth. The effects of the reduction of PVD Discharge Capacity according to depth are more evident when PVD Discharge Capacity decreases. The predicted results using the proposed numerical solution were validated well with the monitoring data for both cases in verification.Research limitations/implicationsIn this study, the variation of PVD Discharge Capacity is only considered in one-dimensional consolidation. However, it is challenging to implement a general expression for Discharge Capacity variation according to time in the two-dimensional numerical solution (two-dimensional plane strain model). This is the motivation for further study.Practical implicationsA geotechnical engineer could use the proposed numerical solution to predict the consolidation behavior of the drainage-improved soft deposit considering the PVD Discharge Capacity variation.Originality/valueThe large-strain consolidation of PVD-installed soft deposits could be predicted well by using the proposed numerical solution considering the PVD Discharge Capacity variations according to depth and time.

  • Nonlinear Analytical Modeling of Vertical Drain-Installed Soft Soil Considering a Varied Discharge Capacity
    Geotechnical and Geological Engineering, 2020
    Co-Authors: Ba-phu Nguyen
    Abstract:

    Discharge Capacity is one of the important factors affecting the consolidation behavior of vertical drains (VDs). Both previous experimental tests and field behavior indicated that the Discharge Capacity of VDs usually decreased with an increase in effective stress. The aim of this study is to develop a nonlinear analytical solution for consolidation analysis of VD-installed soft deposits considering a reduction of Discharge Capacity, in which a nonlinear distribution of VD’s Discharge Capacity with depth is adopted. To verify this work, the proposed solution is compared with previous solutions. The analyzed results show that at a given time and depth, the consolidation rate in the case of Discharge Capacity with a nonlinear distribution is lower than that of a linear and constant distribution. The proposed solution is then applied to a real embankment on the VD-installed thick soft ground in Busan New Port. It is shown that the proposed solution using the nonlinear distribution of VD Discharge Capacity provides a good agreement with the field data.

  • Radial consolidation of PVD-Installed normally consolidated soil with Discharge Capacity reduction using large-strain theory
    Geotextiles and Geomembranes, 2019
    Co-Authors: Ba-phu Nguyen
    Abstract:

    Abstract The radial consolidation rate of prefabricated vertical drain (PVD)-installed soft deposits is known to be closely related to the PVD Discharge Capacity, which usually decreases during consolidation. Conventional solutions for radial consolidation of PVD-installed deposits have been developed to consider Discharge Capacity reduction using small-strain theory, in which the volume compressibility coefficient and soil permeability were assumed to be constant. This paper formulates a general expression for Discharge Capacity reduction with time in numerical analysis based on large-strain theory. Soil disturbance effects caused by PVD installation, such as a nonlinear distribution for radial hydraulic conductivity, are captured in the proposed solution. The proposed solution was applied to field data from a test embankment at Saga Airport. The proposed solution provides a good result which is close to the measured data.

  • Analysis of consolidation behavior of PVD-improved ground considering a varied Discharge Capacity
    Engineering Computations, 2018
    Co-Authors: Yun-tae Kim, Ba-phu Nguyen, Dae-ho Yun
    Abstract:

    Purpose It is well-known that consolidation rate of prefabricated vertical drain (PVD)-installed ground is closely related to the Discharge Capacity of PVD, which decreases with an increase in effective stress. This paper aims to present consolidation behaviors of PVD-improved ground considering a varied Discharge Capacity of PVD. Design/methodology/approach A simple equivalent vertical hydraulic conductivity (k′ve method) was proposed in plane strain numerical analysis, in which the effect of decreased Discharge Capacity with depth was considered. Numerical analysis was applied to analyze field behaviors of test embankment of soft mucky deposit. Findings Finite element method results indicated that consolidation behaviors of PVD-improved soil with a nonlinear distribution of Discharge Capacity with depth were in a good agreement with the observed field behaviors, compared with those with a constant Discharge Capacity and a linear distribution of Discharge Capacity. At a given time and depth, the consolidation rate in the case of Discharge Capacity with a nonlinear distribution is lower than that of a linear or constant distribution. Practical implications A geotechnical engineer could use the proposed method to predict consolidation behaviors of drainage-installed ground. Originality/value Consolidation behaviors of PVD-installed ground could be reasonably predicted by using the proposed method with considering effect of Discharge Capacity reduction.

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

  • high Discharge Capacity of vb2 ni as anode for vb2 air battery
    International Conference on Multimedia and Expo, 2015
    Co-Authors: Qiping Kang, Guoqing Wang, Xin Zhang, Kun Zhang
    Abstract:

    The compound powders of VB 2 with 25 wt% and 50 wt% Ni were mixed uniformly using a planetary ball miller, respectively. The Discharge Capacity of VB2/air battery with VB2-Ni as anode in KOH electrolyte was investigated at room temperature and ambient pressure. Meanwhile, the microstructure of VB2-Ni anode before and after Discharge were analyzed by scanning electron microscope (SEM).The results indicate that the sintered anode material of VB2 with 25 wt% Ni has the highest Discharge Capacity. Moreover, the Discharge Capacity of VB 2/air battery reached 7574 mAh with sintered VB2-Ni25wt% anode, which was much higher than that with unsintered VB2-Ni25wt% anode. However, the Discharge Capacity of VB2/air battery with sintered VB2-Ni50wt% anode was much lower than that with unsintered VB2-Ni50wt% anode. The VB2-Ni25wt% anode sintered at 1050 o C for 30 min is an effective way to improve the Discharge Capacity of VB2/air battery.

M W Bo - One of the best experts on this subject based on the ideXlab platform.

  • laboratory measurements of factors affecting Discharge Capacity of prefabricated vertical drain materials
    Soils and Foundations, 2016
    Co-Authors: M W Bo, Suksun Horpibulsuk, Avirut Chinkulkijniwat, Arul Arulrajah, Melvyn Leong
    Abstract:

    Abstract The Discharge Capacity is a critical parameter controlling the performance of Prefabricated Vertical Drains (PVDs). The laboratory measurement of the Discharge Capacity is of the upmost importance when it comes to assessing the performance of proposed PVDs prior to their usage in the field, and hence, the significance of this paper. However, the laboratory measurement of the Discharge Capacity required to obtain the optimal performance of PVDs by laboratory testing methods is still uncertain. This is because there are various apparatus for Discharge Capacity testing currently in use by various commercial and research organizations, all of which provide widely varying values of Discharge Capacity for the same type of PVD under the same hydraulic conditions. The measured Discharge Capacity of PVDs in the laboratory, with and without surrounding soils, is affected by factors such as the dimensions of the apparatus, the test duration, the hydraulic gradient, the type of surrounding materials, the applied confining pressure and the deformation configuration of the vertical drains. The effects of these factors are investigated, reviewed and discussed in this paper. The relevant equations for obtaining the required Discharge Capacity of PVDs by laboratory methods are also presented and discussed in this paper. The test results indicate that a small tester results in the underestimation of the Discharge Capacity particularly for PVDs with a high Discharge Capacity. A reduction in PVD thickness, the clogging of the filter, the deformation of the PVDs, due to an increase in the duration of the tests (creep), and vertical pressure all cause a reduction in the Discharge Capacity for a particular hydraulic gradient. Softer surrounding soils and lower PVD stiffness cause a large deformation of the soils surrounding the PVDs. For a particular PVD, the creep effect on the decrease in Discharge Capacity is significant with a short duration, but becomes insignificant after a long duration. The deformation of PVDs under folded conditions is found to be the most critical factor in the resulting decrease in Discharge Capacity.

  • Discharge Capacity of prefabricated vertical drain and their field measurements
    Geotextiles and Geomembranes, 2004
    Co-Authors: M W Bo
    Abstract:

    Discharge Capacity is the most important parameter for performance of prefabricated vertical drains. However, the required Discharge Capacity for best performance of vertical drain is still uncertain. This paper described the single basic equation to obtain the required average Discharge Capacity. The estimated values were supported by the field measurement of Discharge Capacity with different drain spacings, different penetration length and different thickness of compressible layers. It was found that required Discharge Capacity is in an order of 10(super -6) m/s for 100 mm width drain. (A) "Reprinted with permission from Elsevier".

Qiping Kang - One of the best experts on this subject based on the ideXlab platform.

  • high Discharge Capacity of vb2 ni as anode for vb2 air battery
    International Conference on Multimedia and Expo, 2015
    Co-Authors: Qiping Kang, Guoqing Wang, Xin Zhang, Kun Zhang
    Abstract:

    The compound powders of VB 2 with 25 wt% and 50 wt% Ni were mixed uniformly using a planetary ball miller, respectively. The Discharge Capacity of VB2/air battery with VB2-Ni as anode in KOH electrolyte was investigated at room temperature and ambient pressure. Meanwhile, the microstructure of VB2-Ni anode before and after Discharge were analyzed by scanning electron microscope (SEM).The results indicate that the sintered anode material of VB2 with 25 wt% Ni has the highest Discharge Capacity. Moreover, the Discharge Capacity of VB 2/air battery reached 7574 mAh with sintered VB2-Ni25wt% anode, which was much higher than that with unsintered VB2-Ni25wt% anode. However, the Discharge Capacity of VB2/air battery with sintered VB2-Ni50wt% anode was much lower than that with unsintered VB2-Ni50wt% anode. The VB2-Ni25wt% anode sintered at 1050 o C for 30 min is an effective way to improve the Discharge Capacity of VB2/air battery.

Guoqing Wang - One of the best experts on this subject based on the ideXlab platform.

  • high Discharge Capacity of vb2 ni as anode for vb2 air battery
    International Conference on Multimedia and Expo, 2015
    Co-Authors: Qiping Kang, Guoqing Wang, Xin Zhang, Kun Zhang
    Abstract:

    The compound powders of VB 2 with 25 wt% and 50 wt% Ni were mixed uniformly using a planetary ball miller, respectively. The Discharge Capacity of VB2/air battery with VB2-Ni as anode in KOH electrolyte was investigated at room temperature and ambient pressure. Meanwhile, the microstructure of VB2-Ni anode before and after Discharge were analyzed by scanning electron microscope (SEM).The results indicate that the sintered anode material of VB2 with 25 wt% Ni has the highest Discharge Capacity. Moreover, the Discharge Capacity of VB 2/air battery reached 7574 mAh with sintered VB2-Ni25wt% anode, which was much higher than that with unsintered VB2-Ni25wt% anode. However, the Discharge Capacity of VB2/air battery with sintered VB2-Ni50wt% anode was much lower than that with unsintered VB2-Ni50wt% anode. The VB2-Ni25wt% anode sintered at 1050 o C for 30 min is an effective way to improve the Discharge Capacity of VB2/air battery.