The Experts below are selected from a list of 2544 Experts worldwide ranked by ideXlab platform
Jinghua Zhang - One of the best experts on this subject based on the ideXlab platform.
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analytical solution for dynamic responses of the vertical Shaft in a Shaft Tunnel junction under transverse loads
Soil Dynamics and Earthquake Engineering, 2019Co-Authors: Jinghua Zhang, Yong Yuan, Emilio Bilotta, Bu ZhangAbstract:Abstract This paper proposes an analytical solution for dynamic responses of the vertical Shaft in a Shaft-Tunnel junction under transverse loads. The assumption is that the Shaft could be regarded as a rigid body under certain circumstances. Based on that premise, equations originally developed for rigid caissons are incorporated with terms of Shaft-Tunnel and soil-Tunnel interactions. Two specific dynamic scenarios are considered. The first one is when the Shaft is subject to transverse dynamic loads above the ground surface. The second one is when the Shaft-Tunnel junction is under transverse seismic excitations. Validity of the proposed solution is examined in both scenarios by finite element method. Then, the proposed solution is used to evaluate influence of the Tunnel. In the first scenario, the Tunnel has a major influence on dynamic responses of the Shaft. Displacements of the Shaft are likely to be reduced because the Tunnel adds to the stiffness matrix. Yet, in the second scenario, influence of the Tunnel is minor enough to be neglected. Seismic responses of the Shaft are approximately the same with or without the Tunnel.
Bilotta E. - One of the best experts on this subject based on the ideXlab platform.
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Analytical solutions for seismic responses of the Tunnel in a Shaft-Tunnel junction under transverse excitations
'Elsevier BV', 2018Co-Authors: Zhang J., Yuan Y., Zhang B., Bilotta E.Abstract:The analytical solutions are proposed for seismic responses of the Tunnel in a Shaft-Tunnel junction under transverse excitations. The vertical Shaft in the junction is regarded as a rigid body. The Tunnel is simplified into a massless beam. It is connected to the Shaft perpendicularly in a fixed end. The surrounding soil is represented by distributed springs and dashpots. Displacements of the Tunnel can be obtained by adopting displacements of the Shaft as boundary conditions for the governing equations. Thereby, analytical solutions for the three major internal forces of the Tunnel are derived. Validity of the proposed solutions is examined by finite element method. The comparison shows that the analytical solutions could provide accurate results of internal forces of the Tunnel at the portion near the junction. However, they become less accurate when the distance to the Shaft increases. Relations between the internal forces and physical parameters of the soil-Shaft-Tunnel system are discussed. Distributions of the internal forces along the Tunnel axis are highly dependent on the stiffness of the soil and the Tunnel, while amplitudes of the internal forces are also determined by the amount of Shaft-soil relative displacements. When the connection between Shaft and Tunnel is replaced by a pin joint as a conceptual aseismic measure, the maximum shearing force and the maximum bending moment of the Tunnel would be both significantly reduced. © 2019 Elsevier Lt
Bu Zhang - One of the best experts on this subject based on the ideXlab platform.
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analytical solution for dynamic responses of the vertical Shaft in a Shaft Tunnel junction under transverse loads
Soil Dynamics and Earthquake Engineering, 2019Co-Authors: Jinghua Zhang, Yong Yuan, Emilio Bilotta, Bu ZhangAbstract:Abstract This paper proposes an analytical solution for dynamic responses of the vertical Shaft in a Shaft-Tunnel junction under transverse loads. The assumption is that the Shaft could be regarded as a rigid body under certain circumstances. Based on that premise, equations originally developed for rigid caissons are incorporated with terms of Shaft-Tunnel and soil-Tunnel interactions. Two specific dynamic scenarios are considered. The first one is when the Shaft is subject to transverse dynamic loads above the ground surface. The second one is when the Shaft-Tunnel junction is under transverse seismic excitations. Validity of the proposed solution is examined in both scenarios by finite element method. Then, the proposed solution is used to evaluate influence of the Tunnel. In the first scenario, the Tunnel has a major influence on dynamic responses of the Shaft. Displacements of the Shaft are likely to be reduced because the Tunnel adds to the stiffness matrix. Yet, in the second scenario, influence of the Tunnel is minor enough to be neglected. Seismic responses of the Shaft are approximately the same with or without the Tunnel.
Zhang J. - One of the best experts on this subject based on the ideXlab platform.
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Analytical solutions for seismic responses of the Tunnel in a Shaft-Tunnel junction under transverse excitations
'Elsevier BV', 2018Co-Authors: Zhang J., Yuan Y., Zhang B., Bilotta E.Abstract:The analytical solutions are proposed for seismic responses of the Tunnel in a Shaft-Tunnel junction under transverse excitations. The vertical Shaft in the junction is regarded as a rigid body. The Tunnel is simplified into a massless beam. It is connected to the Shaft perpendicularly in a fixed end. The surrounding soil is represented by distributed springs and dashpots. Displacements of the Tunnel can be obtained by adopting displacements of the Shaft as boundary conditions for the governing equations. Thereby, analytical solutions for the three major internal forces of the Tunnel are derived. Validity of the proposed solutions is examined by finite element method. The comparison shows that the analytical solutions could provide accurate results of internal forces of the Tunnel at the portion near the junction. However, they become less accurate when the distance to the Shaft increases. Relations between the internal forces and physical parameters of the soil-Shaft-Tunnel system are discussed. Distributions of the internal forces along the Tunnel axis are highly dependent on the stiffness of the soil and the Tunnel, while amplitudes of the internal forces are also determined by the amount of Shaft-soil relative displacements. When the connection between Shaft and Tunnel is replaced by a pin joint as a conceptual aseismic measure, the maximum shearing force and the maximum bending moment of the Tunnel would be both significantly reduced. © 2019 Elsevier Lt
Xiangliang Tian - One of the best experts on this subject based on the ideXlab platform.
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temperature profile of fire induced smoke in node area of a full scale mine Shaft Tunnel under natural ventilation
Applied Thermal Engineering, 2017Co-Authors: Chang Liu, Congling Shi, Maohua Zhong, Peihong Zhang, Xiangliang TianAbstract:Abstract This paper investigated ceiling temperature profile of fire-induce smoke in the common node area of Tunnels. The experiments were conducted in a full-scale mine Shaft Tunnel under natural ventilation with the node area consisted of a straight Tunnel and two curved Tunnels. Maximum ceiling temperature above the fire, transverse ceiling temperature along the elliptic ceiling and longitudinal ceiling temperature along the main and branch Tunnels were measured by K-type thermocouples or thermometric cable. Dimensionless expression for predicting transverse and longitudinal ceiling temperature distribution was proposed based on previous models. Normalized expression of longitudinal temperature decay coefficients were correlated as well by taking the heat release rate and transverse fire locations under the elliptic ceiling into account. Then the results calculated by the proposed formula were compared with the experimental measured maximum ceiling temperature along the main Tunnel and shows good agreement. Finally, effects of vertical wall and ceiling height on temperature decay trend in branch Tunnels were investigated by analyzing the accumulation and descendant of smoke in front of the portals based on measured temperature data.