The Experts below are selected from a list of 42 Experts worldwide ranked by ideXlab platform

Yuko Okada - One of the best experts on this subject based on the ideXlab platform.

  • Development of a new deformation-controlled rock Bolt: Numerical modelling and laboratory verification
    Tunnelling and Underground Space Technology, 2020
    Co-Authors: Yasuhiro Yokota, Zhiye Zhao, Kensuke Date, Keita Iwano, Yu Koizumi, Yuko Okada
    Abstract:

    Abstract To prevent large tunnel deformations caused by the rock bursts or the squeezing ground conditions, the rock Bolts used should satisfy both strength capacity and the required deformability. Currently, the energy-absorbing rock Bolts, such as the Cone Bolt and D Bolt, have been successfully utilised in the deep mining to avoid sudden tunnel collapses. However, a rigid type rock Bolt (e.g. a fully grouted rock Bolt) is still commonly used in civil engineering tunnels even when they are excavated under a high overburden pressure with poor geological conditions. In such cases, the rock Bolt might fail in tension due to the large deformation. This paper proposed a new energy-absorbing rock Bolt, which is referred to as a deformation-controlled rock Bolt (DC-Bolt). The performance of the proposed DC-Bolt was verified by the numerical simulations using the discontinuous deformation analysis (DDA) and by the prototype laboratory tests. This study concluded that the DC-Bolt possesses both the high loading capacity and the deformable capacity. Additionally, the DC-Bolt can limit the rock surface movement when it reaches a certain displacement, thus, it can be a useful tunnel support for civil engineering tunnels excavated under the squeezing ground condition.

  • Development of a new deformation-controlled rockBolt: numerical modelling and laboratory verification
    Proceedings of the Ninth International Symposium on Ground Support in Mining and Underground Construction, 2019
    Co-Authors: Yasuhiro Yokota, Zhiye Zhao, Kensuke Date, Keita Iwano, Yu Koizumi, Yuko Okada
    Abstract:

    To prevent large tunnel deformations caused by rock bursts or squeezing ground conditions, rockBolts need to satisfy both strength capacity and the required deformability. Currently, energy-absorbing rockBolts, such as the Cone Bolt and the D-Bolt, have been successfully used in deep mining to avoid sudden tunnel collapses. This paper proposes a new energy-absorbing rockBolt, referred to as a deformation-controlled rockBolt (DC-Bolt). The performance of the proposed DC-Bolt was verified by numerical simulations using discontinuous deformation analysis (DDA) and by prototype laboratory tests. As a result, it is concluded that the DC-Bolt possesses both high loading capacity and deformation capacity. Additionally, the DC-Bolt can limit rock surface movement when it reaches a certain displacement. Thus, it can be a useful tunnel support for tunnels that are to be excavated in squeezing ground conditions.

Zhiye Zhao - One of the best experts on this subject based on the ideXlab platform.

  • Development of a new deformation-controlled rock Bolt: Numerical modelling and laboratory verification
    Tunnelling and Underground Space Technology, 2020
    Co-Authors: Yasuhiro Yokota, Zhiye Zhao, Kensuke Date, Keita Iwano, Yu Koizumi, Yuko Okada
    Abstract:

    Abstract To prevent large tunnel deformations caused by the rock bursts or the squeezing ground conditions, the rock Bolts used should satisfy both strength capacity and the required deformability. Currently, the energy-absorbing rock Bolts, such as the Cone Bolt and D Bolt, have been successfully utilised in the deep mining to avoid sudden tunnel collapses. However, a rigid type rock Bolt (e.g. a fully grouted rock Bolt) is still commonly used in civil engineering tunnels even when they are excavated under a high overburden pressure with poor geological conditions. In such cases, the rock Bolt might fail in tension due to the large deformation. This paper proposed a new energy-absorbing rock Bolt, which is referred to as a deformation-controlled rock Bolt (DC-Bolt). The performance of the proposed DC-Bolt was verified by the numerical simulations using the discontinuous deformation analysis (DDA) and by the prototype laboratory tests. This study concluded that the DC-Bolt possesses both the high loading capacity and the deformable capacity. Additionally, the DC-Bolt can limit the rock surface movement when it reaches a certain displacement, thus, it can be a useful tunnel support for civil engineering tunnels excavated under the squeezing ground condition.

  • Development of a new deformation-controlled rockBolt: numerical modelling and laboratory verification
    Proceedings of the Ninth International Symposium on Ground Support in Mining and Underground Construction, 2019
    Co-Authors: Yasuhiro Yokota, Zhiye Zhao, Kensuke Date, Keita Iwano, Yu Koizumi, Yuko Okada
    Abstract:

    To prevent large tunnel deformations caused by rock bursts or squeezing ground conditions, rockBolts need to satisfy both strength capacity and the required deformability. Currently, energy-absorbing rockBolts, such as the Cone Bolt and the D-Bolt, have been successfully used in deep mining to avoid sudden tunnel collapses. This paper proposes a new energy-absorbing rockBolt, referred to as a deformation-controlled rockBolt (DC-Bolt). The performance of the proposed DC-Bolt was verified by numerical simulations using discontinuous deformation analysis (DDA) and by prototype laboratory tests. As a result, it is concluded that the DC-Bolt possesses both high loading capacity and deformation capacity. Additionally, the DC-Bolt can limit rock surface movement when it reaches a certain displacement. Thus, it can be a useful tunnel support for tunnels that are to be excavated in squeezing ground conditions.

  • Development of a Unified Rock Bolt Model in Discontinuous Deformation Analysis
    Rock Mechanics and Rock Engineering, 2017
    Co-Authors: Lei He, Zhiye Zhao, Xinmei An, Xiaobao Zhao, Jian Zhao
    Abstract:

    In this paper, a unified rock Bolt model is proposed and incorporated into the two-dimensional discontinuous deformation analysis. In the model, the Bolt shank is discretized into a finite number of (modified) Euler–Bernoulli beam elements with the degrees of freedom represented at the end nodes, while the face plate is treated as solid blocks. The rock mass and the Bolt shank deform independently, but interact with each other through a few anchored points. The interactions between the rock mass and the face plate are handled via general contact algorithm. Different types of rock Bolts (e.g., Expansion Shell, fully grouted rebar, Split Set, Cone Bolt, Roofex, Garford and D-Bolt) can be realized by specifying the corresponding constitutive model for the tangential behavior of the anchored points. Four failure modes, namely tensile failure and shear failure of the Bolt shank, debonding along the Bolt/rock interface and loss of the face plate, are available in the analysis procedure. The performance of a typical conventional rock Bolt (fully grouted rebar) and a typical energy-absorbing rock Bolt (D-Bolt) under the scenarios of suspending loosened blocks and rock dilation is investigated using the proposed model. The reliability of the proposed model is verified by comparing the simulation results with theoretical predictions and experimental observations. The proposed model could be used to reveal the mechanism of each type of rock Bolt in realistic scenarios and to provide a numerical way for presenting the detailed profile about the behavior of Bolts, in particular at intermediate loading stages.

Yasuhiro Yokota - One of the best experts on this subject based on the ideXlab platform.

  • Development of a new deformation-controlled rock Bolt: Numerical modelling and laboratory verification
    Tunnelling and Underground Space Technology, 2020
    Co-Authors: Yasuhiro Yokota, Zhiye Zhao, Kensuke Date, Keita Iwano, Yu Koizumi, Yuko Okada
    Abstract:

    Abstract To prevent large tunnel deformations caused by the rock bursts or the squeezing ground conditions, the rock Bolts used should satisfy both strength capacity and the required deformability. Currently, the energy-absorbing rock Bolts, such as the Cone Bolt and D Bolt, have been successfully utilised in the deep mining to avoid sudden tunnel collapses. However, a rigid type rock Bolt (e.g. a fully grouted rock Bolt) is still commonly used in civil engineering tunnels even when they are excavated under a high overburden pressure with poor geological conditions. In such cases, the rock Bolt might fail in tension due to the large deformation. This paper proposed a new energy-absorbing rock Bolt, which is referred to as a deformation-controlled rock Bolt (DC-Bolt). The performance of the proposed DC-Bolt was verified by the numerical simulations using the discontinuous deformation analysis (DDA) and by the prototype laboratory tests. This study concluded that the DC-Bolt possesses both the high loading capacity and the deformable capacity. Additionally, the DC-Bolt can limit the rock surface movement when it reaches a certain displacement, thus, it can be a useful tunnel support for civil engineering tunnels excavated under the squeezing ground condition.

  • Development of a new deformation-controlled rockBolt: numerical modelling and laboratory verification
    Proceedings of the Ninth International Symposium on Ground Support in Mining and Underground Construction, 2019
    Co-Authors: Yasuhiro Yokota, Zhiye Zhao, Kensuke Date, Keita Iwano, Yu Koizumi, Yuko Okada
    Abstract:

    To prevent large tunnel deformations caused by rock bursts or squeezing ground conditions, rockBolts need to satisfy both strength capacity and the required deformability. Currently, energy-absorbing rockBolts, such as the Cone Bolt and the D-Bolt, have been successfully used in deep mining to avoid sudden tunnel collapses. This paper proposes a new energy-absorbing rockBolt, referred to as a deformation-controlled rockBolt (DC-Bolt). The performance of the proposed DC-Bolt was verified by numerical simulations using discontinuous deformation analysis (DDA) and by prototype laboratory tests. As a result, it is concluded that the DC-Bolt possesses both high loading capacity and deformation capacity. Additionally, the DC-Bolt can limit rock surface movement when it reaches a certain displacement. Thus, it can be a useful tunnel support for tunnels that are to be excavated in squeezing ground conditions.

Jacques Ouellet - One of the best experts on this subject based on the ideXlab platform.

  • development of a dynamic model for a Cone Bolt
    International Journal of Rock Mechanics and Mining Sciences, 2009
    Co-Authors: Luc Stpierre, Ferri P Hassani, Peter Radziszewski, Jacques Ouellet
    Abstract:

    Abstract To ensure safety in underground excavations, it is important that the support systems used are capable of resisting the dynamic loads produced, for example, by rock bursts. In this paper, a dynamic simulation model for a Cone Bolt is proposed based on an experimental study. Drop weight tests were performed on resin-based Cone Bolts. These experiments revealed that the Bolt has two energy absorption mechanisms: sliding in the resin and plastic deformation. To simulate this behaviour, a two degrees-of-freedom lumped-mass model is proposed. Experimentally, the proportions of sliding and plastic deformation were found to vary significantly from one test to another. To account for this variability, two methods are proposed to determine the value of the parameters governing the sliding of the Bolt in the resin, whereas a dynamic force–elongation model is used to simulate the plastic deformation. Comparing the results of a simulation to experimental data proved that the constitutive elements of the model are appropriate to simulate the dynamic response of the Cone Bolt.

Yu Koizumi - One of the best experts on this subject based on the ideXlab platform.

  • Development of a new deformation-controlled rock Bolt: Numerical modelling and laboratory verification
    Tunnelling and Underground Space Technology, 2020
    Co-Authors: Yasuhiro Yokota, Zhiye Zhao, Kensuke Date, Keita Iwano, Yu Koizumi, Yuko Okada
    Abstract:

    Abstract To prevent large tunnel deformations caused by the rock bursts or the squeezing ground conditions, the rock Bolts used should satisfy both strength capacity and the required deformability. Currently, the energy-absorbing rock Bolts, such as the Cone Bolt and D Bolt, have been successfully utilised in the deep mining to avoid sudden tunnel collapses. However, a rigid type rock Bolt (e.g. a fully grouted rock Bolt) is still commonly used in civil engineering tunnels even when they are excavated under a high overburden pressure with poor geological conditions. In such cases, the rock Bolt might fail in tension due to the large deformation. This paper proposed a new energy-absorbing rock Bolt, which is referred to as a deformation-controlled rock Bolt (DC-Bolt). The performance of the proposed DC-Bolt was verified by the numerical simulations using the discontinuous deformation analysis (DDA) and by the prototype laboratory tests. This study concluded that the DC-Bolt possesses both the high loading capacity and the deformable capacity. Additionally, the DC-Bolt can limit the rock surface movement when it reaches a certain displacement, thus, it can be a useful tunnel support for civil engineering tunnels excavated under the squeezing ground condition.

  • Development of a new deformation-controlled rockBolt: numerical modelling and laboratory verification
    Proceedings of the Ninth International Symposium on Ground Support in Mining and Underground Construction, 2019
    Co-Authors: Yasuhiro Yokota, Zhiye Zhao, Kensuke Date, Keita Iwano, Yu Koizumi, Yuko Okada
    Abstract:

    To prevent large tunnel deformations caused by rock bursts or squeezing ground conditions, rockBolts need to satisfy both strength capacity and the required deformability. Currently, energy-absorbing rockBolts, such as the Cone Bolt and the D-Bolt, have been successfully used in deep mining to avoid sudden tunnel collapses. This paper proposes a new energy-absorbing rockBolt, referred to as a deformation-controlled rockBolt (DC-Bolt). The performance of the proposed DC-Bolt was verified by numerical simulations using discontinuous deformation analysis (DDA) and by prototype laboratory tests. As a result, it is concluded that the DC-Bolt possesses both high loading capacity and deformation capacity. Additionally, the DC-Bolt can limit rock surface movement when it reaches a certain displacement. Thus, it can be a useful tunnel support for tunnels that are to be excavated in squeezing ground conditions.