The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform

Hirofumi Koga - One of the best experts on this subject based on the ideXlab platform.

  • lateral displacement of ground caused by soil cement column Installation
    Journal of Geotechnical and Geoenvironmental Engineering, 2005
    Co-Authors: Jinchun Chai, Norihiko Miura, Hirofumi Koga
    Abstract:

    Closed form equations for calculating the lateral displacement caused by the Installation of soil-cement columns are derived based on cylindrical cavity expansion theory. The radius of the cavity needs to be predetermined empirically, mainly with reference to the amount of admixture injected and injection pressure as well as the stiffness of the surrounding soil. Also, an empirical equation is proposed for considering the partial "plane strain" effect of installing a row of columns. The proposed method has been applied to four reported field tests conducted in Saga, Japan, using the slurry double mixing ~SDM! method, the dry jet mixing ~DJM! method, and the wet jet mixing ~WJM! method. The radius of influence, i.e., where the lateral displacement in the soil is less than 5 mm during the Installation of soil-cement columns, is found from the field data to be approximately 30, 40, and 50 m for the SDM, DJM, and WJM, respectively. It is shown that the proposed method yielded a reasonable prediction of these field measurements. The field data also indicate that the Installation Sequence has a considerable influence on the observed lateral displacement; but the proposed method can only consider two extreme conditions of this influence. It is suggested that the method is a useful tool for the design of soft subsoil improvement resulting from the Installation of soil-cement columns.

  • Lateral Displacement of Ground Caused by Soil–Cement Column Installation
    Journal of Geotechnical and Geoenvironmental Engineering, 2005
    Co-Authors: Jinchun Chai, Norihiko Miura, Hirofumi Koga
    Abstract:

    Closed form equations for calculating the lateral displacement caused by the Installation of soil-cement columns are derived based on cylindrical cavity expansion theory. The radius of the cavity needs to be predetermined empirically, mainly with reference to the amount of admixture injected and injection pressure as well as the stiffness of the surrounding soil. Also, an empirical equation is proposed for considering the partial "plane strain" effect of installing a row of columns. The proposed method has been applied to four reported field tests conducted in Saga, Japan, using the slurry double mixing ~SDM! method, the dry jet mixing ~DJM! method, and the wet jet mixing ~WJM! method. The radius of influence, i.e., where the lateral displacement in the soil is less than 5 mm during the Installation of soil-cement columns, is found from the field data to be approximately 30, 40, and 50 m for the SDM, DJM, and WJM, respectively. It is shown that the proposed method yielded a reasonable prediction of these field measurements. The field data also indicate that the Installation Sequence has a considerable influence on the observed lateral displacement; but the proposed method can only consider two extreme conditions of this influence. It is suggested that the method is a useful tool for the design of soft subsoil improvement resulting from the Installation of soil-cement columns.

Liu Jing - One of the best experts on this subject based on the ideXlab platform.

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

  • lateral displacement of ground caused by soil cement column Installation
    Journal of Geotechnical and Geoenvironmental Engineering, 2005
    Co-Authors: Jinchun Chai, Norihiko Miura, Hirofumi Koga
    Abstract:

    Closed form equations for calculating the lateral displacement caused by the Installation of soil-cement columns are derived based on cylindrical cavity expansion theory. The radius of the cavity needs to be predetermined empirically, mainly with reference to the amount of admixture injected and injection pressure as well as the stiffness of the surrounding soil. Also, an empirical equation is proposed for considering the partial "plane strain" effect of installing a row of columns. The proposed method has been applied to four reported field tests conducted in Saga, Japan, using the slurry double mixing ~SDM! method, the dry jet mixing ~DJM! method, and the wet jet mixing ~WJM! method. The radius of influence, i.e., where the lateral displacement in the soil is less than 5 mm during the Installation of soil-cement columns, is found from the field data to be approximately 30, 40, and 50 m for the SDM, DJM, and WJM, respectively. It is shown that the proposed method yielded a reasonable prediction of these field measurements. The field data also indicate that the Installation Sequence has a considerable influence on the observed lateral displacement; but the proposed method can only consider two extreme conditions of this influence. It is suggested that the method is a useful tool for the design of soft subsoil improvement resulting from the Installation of soil-cement columns.

  • Lateral Displacement of Ground Caused by Soil–Cement Column Installation
    Journal of Geotechnical and Geoenvironmental Engineering, 2005
    Co-Authors: Jinchun Chai, Norihiko Miura, Hirofumi Koga
    Abstract:

    Closed form equations for calculating the lateral displacement caused by the Installation of soil-cement columns are derived based on cylindrical cavity expansion theory. The radius of the cavity needs to be predetermined empirically, mainly with reference to the amount of admixture injected and injection pressure as well as the stiffness of the surrounding soil. Also, an empirical equation is proposed for considering the partial "plane strain" effect of installing a row of columns. The proposed method has been applied to four reported field tests conducted in Saga, Japan, using the slurry double mixing ~SDM! method, the dry jet mixing ~DJM! method, and the wet jet mixing ~WJM! method. The radius of influence, i.e., where the lateral displacement in the soil is less than 5 mm during the Installation of soil-cement columns, is found from the field data to be approximately 30, 40, and 50 m for the SDM, DJM, and WJM, respectively. It is shown that the proposed method yielded a reasonable prediction of these field measurements. The field data also indicate that the Installation Sequence has a considerable influence on the observed lateral displacement; but the proposed method can only consider two extreme conditions of this influence. It is suggested that the method is a useful tool for the design of soft subsoil improvement resulting from the Installation of soil-cement columns.

Georg Anagnostou - One of the best experts on this subject based on the ideXlab platform.

  • Stability Under Seepage Flow Conditions of a Tunnel Face Reinforced by Bolts
    Procedia Engineering, 2017
    Co-Authors: Paolo Perazzelli, G. Cimbali, Georg Anagnostou
    Abstract:

    Abstract We propose a computational method for assessing bolt reinforcement of the tunnel face in cohesive frictional soils and weak rocks under seepage flow conditions. The method is based on limit equilibrium factors and can be applied to reinforcement layouts that are arbitrary in terms of the spacing, length, longitudinal overlapping and Installation Sequence of the bolts. An investigation is made into the influence of water table height on the stability of a reinforced face. In particular, we show that, if the gradient of the hydraulic head is high, then tensile failure of the ground ahead of the face may be more critical than shear failure. For an approximate hydraulic head distribution in the ground around the tunnel face and assuming uniform face reinforcement, we derive a closed-form solution for the necessary bolting density.

  • analysis method and design charts for bolt reinforcement of the tunnel face in cohesive frictional soils
    Tunnelling and Underground Space Technology, 2015
    Co-Authors: Georg Anagnostou, Paolo Perazzelli
    Abstract:

    We propose a computational method for assessing bolt reinforcement of the tunnel face in cohesive-frictional soils. The method is based on limit equilibrium considerations and can be applied to heterogeneous, layered ground as well as to reinforcement layouts that are arbitrary in terms of the spacing, length, longitudinal overlapping and Installation Sequence of the bolts. A closed-form solution is presented for the special case of a homogeneous ground with uniform face reinforcement. An investigation is made into the influence of the unsupported span and the reinforcement scheme on face stability. The case of a stress-dependent bond strength is analysed and the results are compared with results of numerical analyses. Design nomograms are presented for the assessment of tunnel face stability in a homogeneous ground with uniformly distributed bolts, constant or variable bond strength and various Installation Sequences.

  • The dimensioning of tunnel face reinforcement
    2007
    Co-Authors: Georg Anagnostou, Konstantinos Serafeimidis
    Abstract:

    Ground reinforcement using fiberglass or steel bolts is a very efficient measure for stabilizing the face in conventional tunneling. The reinforcement needs a careful design in order to optimize the construction process. This paper presents a computational method which is based upon limit equilibrium considerations and which can be applied to heterogeneous, layered ground aswell as to arbitrary reinforcement layouts in terms of the spacing, length, longitudinal overlapping and Installation Sequence of the bolts. Additionally, design nomograms are presented for the assessment of tunnel face stability in the special case of a homogeneous ground with uniform reinforcement.

Norihiko Miura - One of the best experts on this subject based on the ideXlab platform.

  • lateral displacement of ground caused by soil cement column Installation
    Journal of Geotechnical and Geoenvironmental Engineering, 2005
    Co-Authors: Jinchun Chai, Norihiko Miura, Hirofumi Koga
    Abstract:

    Closed form equations for calculating the lateral displacement caused by the Installation of soil-cement columns are derived based on cylindrical cavity expansion theory. The radius of the cavity needs to be predetermined empirically, mainly with reference to the amount of admixture injected and injection pressure as well as the stiffness of the surrounding soil. Also, an empirical equation is proposed for considering the partial "plane strain" effect of installing a row of columns. The proposed method has been applied to four reported field tests conducted in Saga, Japan, using the slurry double mixing ~SDM! method, the dry jet mixing ~DJM! method, and the wet jet mixing ~WJM! method. The radius of influence, i.e., where the lateral displacement in the soil is less than 5 mm during the Installation of soil-cement columns, is found from the field data to be approximately 30, 40, and 50 m for the SDM, DJM, and WJM, respectively. It is shown that the proposed method yielded a reasonable prediction of these field measurements. The field data also indicate that the Installation Sequence has a considerable influence on the observed lateral displacement; but the proposed method can only consider two extreme conditions of this influence. It is suggested that the method is a useful tool for the design of soft subsoil improvement resulting from the Installation of soil-cement columns.

  • Lateral Displacement of Ground Caused by Soil–Cement Column Installation
    Journal of Geotechnical and Geoenvironmental Engineering, 2005
    Co-Authors: Jinchun Chai, Norihiko Miura, Hirofumi Koga
    Abstract:

    Closed form equations for calculating the lateral displacement caused by the Installation of soil-cement columns are derived based on cylindrical cavity expansion theory. The radius of the cavity needs to be predetermined empirically, mainly with reference to the amount of admixture injected and injection pressure as well as the stiffness of the surrounding soil. Also, an empirical equation is proposed for considering the partial "plane strain" effect of installing a row of columns. The proposed method has been applied to four reported field tests conducted in Saga, Japan, using the slurry double mixing ~SDM! method, the dry jet mixing ~DJM! method, and the wet jet mixing ~WJM! method. The radius of influence, i.e., where the lateral displacement in the soil is less than 5 mm during the Installation of soil-cement columns, is found from the field data to be approximately 30, 40, and 50 m for the SDM, DJM, and WJM, respectively. It is shown that the proposed method yielded a reasonable prediction of these field measurements. The field data also indicate that the Installation Sequence has a considerable influence on the observed lateral displacement; but the proposed method can only consider two extreme conditions of this influence. It is suggested that the method is a useful tool for the design of soft subsoil improvement resulting from the Installation of soil-cement columns.