The Experts below are selected from a list of 10482 Experts worldwide ranked by ideXlab platform

Jie Peng - One of the best experts on this subject based on the ideXlab platform.

  • analytical solution for vacuum preloading considering the nonlinear distribution of Horizontal Permeability within the smear zone
    PLOS ONE, 2015
    Co-Authors: Jie Peng
    Abstract:

    The vacuum preloading is an effective method which is widely used in ground treatment. In consolidation analysis, the soil around prefabricated vertical drain (PVD) is traditionally divided into smear zone and undisturbed zone, both with constant Permeability. In reality, the Permeability of soil changes continuously within the smear zone. In this study, the Horizontal Permeability coefficient of soil within the smear zone is described by an exponential function of radial distance. A solution for vacuum preloading consolidation considers the nonlinear distribution of Horizontal Permeability within the smear zone is presented and compared with previous analytical results as well as a numerical solution, the results show that the presented solution correlates well with the numerical solution, and is more precise than previous analytical solution.

W Y Jang - One of the best experts on this subject based on the ideXlab platform.

  • observational method for field performance of prefabricated vertical drains
    Geotextiles and Geomembranes, 2014
    Co-Authors: S G Chung, H J Kweon, W Y Jang
    Abstract:

    Abstract An exponential formula is used to best-fit theoretical and measured time–settlement (or excess pore pressure) data over the full range of consolidation. The formula fits well theoretical consolidation solutions and measured data regardless of using the incompletely consolidated data, and it is possible to reliably predict the ultimate values. This result has a different trend from those of the hyperbolic and Asaoka (1978) methods. Thus the coefficients of Horizontal consolidation and the mobilised discharge capacity qw(mob) can be expressed in terms of parameters of the exponential formula corresponding to the measured data and the theoretical solutions. The application of the proposed method to six case records on three construction sites (with a maximum drainage path lm of 7−50 m) indicates that the coefficient of Horizontal consolidation for the ideal condition are likely to be used to reconstruct the monitored time–settlement curve and also to adjust the hydraulic and consolidation properties of each monitored point. Based on back-analysis, the mobilised and required discharge capacity for a preliminary design guideline are recommended as: qw(mob) = (1–5)khlm2 and qw(req) = 19.63khlm2, where kh is the Horizontal Permeability of soil.

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

  • convective stability analysis of the long term storage of carbon dioxide in deep saline aquifers
    Advances in Water Resources, 2006
    Co-Authors: Shiyi Chen, Dongxiao Zhang
    Abstract:

    Deep saline aquifers are one of the most suitable geologic formations for carbon sequestration. The linear and global stability analysis of the time-dependent density-driven convection in deep saline aquifers is presented for long-term storage of carbon dioxide (CO2). The convective mixing that can greatly accelerate the CO2 dissolution into saline aquifers arises because the density of brine increases upon the dissolution of CO2 and such a density difference may induce instability. The effects of anisotropic Permeability on the stability criteria, such as the critical time for the appearance of convective phenomena and the critical wavelength of the most unstable perturbation, are investigated with linear and global stability analysis. The linear stability analysis provides a sufficient condition for instability while the global stability analysis yields a sufficient condition for stability. The results obtained from these two approaches are not exactly the same but show a consistent trend, both indicating that the anisotropic system becomes more unstable when either the vertical or Horizontal Permeability increases. � 2005 Elsevier Ltd. All rights reserved.

Buddhima Indraratna - One of the best experts on this subject based on the ideXlab platform.

  • laboratory evaluation of smear zone and correlation between Permeability and moisture content
    Journal of Geotechnical and Geoenvironmental Engineering, 2006
    Co-Authors: Iyathurai Sathananthan, Buddhima Indraratna
    Abstract:

    In this study, the extent of the smear zone and the reduction of Permeability and water content within the smear zone were investigated using a large-scale consolidometer. The installation of vertical drains by means of a mandrel causes significant disturbance of the subsoil surrounding the mandrel, resulting in a smear zone. The extent of the smear zone for Moruya clay (New South Wales, Australia) was estimated on the basis of normalized Permeability and the reduction of water content by taking undisturbed samples (Horizontally and vertically) at different locations. This study reveals that a significant reduction in water content and Horizontal Permeability takes place towards the drain, whereas the variation in the vertical Permeability is negligible. The smear zone for Moruya clay was found to be 2.5 times the equivalent radius of the mandrel with the Horizontal Permeability varying from 1.09 to 1.64, an average of 1.34 times smaller than that of the undisturbed zone. Finally, a correlation between the Permeability decrease and water content reduction within smear zone is proposed.

  • radial consolidation of clay using compressibility indices and varying Horizontal Permeability
    Canadian Geotechnical Journal, 2005
    Co-Authors: Buddhima Indraratna, Cholachat Rujikiatkamjorn, Iyathurai Sathananthan
    Abstract:

    A system of vertical drains, with surcharge load to accelerate consolidation by shortening the drainage path, is one of the most popular methods of soft ground improvement. The conventional radial ...

  • LABORATORY DETERMINATION OF SMEAR ZONE DUE TO VERTICAL DRAIN INSTALLATION. TECHNICAL NOTE
    Journal of Geotechnical and Geoenvironmental Engineering, 1998
    Co-Authors: Buddhima Indraratna, I Wayan Redana
    Abstract:

    This paper is concerned with a laboratory study to investigate the effect of smear due to vertical drain installation. The extent of the smear zone around a vertical drain was studied utilizing a large-scale consolidometer apparatus. The test results reveal that a significant reduction in the Horizontal Permeability takes place toward the central drain, whereas the vertical Permeability remains relatively unchanged. The radius of the smear zone was estimated to be a factor of four to five times the radius of the central drain (mandrel), and the measured ratio of Horizontal to vertical Permeability approached unity at the drain-soil interface. The laboratory measured settlements are subsequently compared with the predictions based on the theory of Hansbo and the finite element method. It is of relevance to note that the inclusion of the correct variation of Permeability ratios of the smear zone in the plane strain finite element analysis improves the accuracy of settlement predictions.

  • Laboratory Determination of Smear Zone due to Vertical Drain Installation
    Journal of Geotechnical and Geoenvironmental Engineering, 1998
    Co-Authors: Buddhima Indraratna, I Wayan Redana
    Abstract:

    This paper is mainly concerned with a laboratory study to investigate the effect of smear due to vertical drain installation. The extent of the smear zone around a vertical drain was studied utilizing a large-scale consolidometer apparatus. The test results reveal that a significant reduction in the Horizontal Permeability takes place toward the central drain, whereas the vertical Permeability remains relatively unchanged. The radius of the smear zone was estimated to be a factor of four to five times the radius of the central drain (mandrel), and the measured ratio of Horizontal to vertical Permeability approached unity at the drain-soil interface. The laboratory measured settlements are subsequently compared with the predictions based on the theory of Hansbo and the finite element method. It is of relevance to note that the inclusion of the correct variation of Permeability ratios of the smear zone in the plane strain finite element analysis improves the accuracy of settlement predictions.

S G Chung - One of the best experts on this subject based on the ideXlab platform.

  • observational method for field performance of prefabricated vertical drains
    Geotextiles and Geomembranes, 2014
    Co-Authors: S G Chung, H J Kweon, W Y Jang
    Abstract:

    Abstract An exponential formula is used to best-fit theoretical and measured time–settlement (or excess pore pressure) data over the full range of consolidation. The formula fits well theoretical consolidation solutions and measured data regardless of using the incompletely consolidated data, and it is possible to reliably predict the ultimate values. This result has a different trend from those of the hyperbolic and Asaoka (1978) methods. Thus the coefficients of Horizontal consolidation and the mobilised discharge capacity qw(mob) can be expressed in terms of parameters of the exponential formula corresponding to the measured data and the theoretical solutions. The application of the proposed method to six case records on three construction sites (with a maximum drainage path lm of 7−50 m) indicates that the coefficient of Horizontal consolidation for the ideal condition are likely to be used to reconstruct the monitored time–settlement curve and also to adjust the hydraulic and consolidation properties of each monitored point. Based on back-analysis, the mobilised and required discharge capacity for a preliminary design guideline are recommended as: qw(mob) = (1–5)khlm2 and qw(req) = 19.63khlm2, where kh is the Horizontal Permeability of soil.