Analytical and Numerical Anti-Floating Study Concerning the Shield Tunnel across the River

2013 ◽  
Vol 671-674 ◽  
pp. 1087-1092 ◽  
Author(s):  
Shao Qin Zhang ◽  
Wen Jun Yuan ◽  
Hui Hua Zhang ◽  
Ling Huang ◽  
Yan Fen Zhong
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Comparative Study ◽  
Equilibrium States ◽  
Shield Tunnel ◽  
Minimum Thickness ◽  
Soil Thickness

In the present paper, we consider the floating problem of river-crossing shield tunnel in the process of construction. Firstly, based on the theoretical analysis of equilibrium states of excavation face and shield segments away from shield tail, we obtain the equation for calculating the minimum thickness of overlying soil in the associated equilibrium states. Secondly, the above derived formula are applied in the Fuhe bridge project, which is a sub-project of No.1 Nanchang metro; at the same time, numerical simulation is carried out to further evaluate the safety with the change of overlying soil thickness. Lastly, some useful conclusions are drawn through comparative study, which is helpful to similar projects.

scholarly journals Numerical Simulation of EPB Shield Tunnelling with TBM Operational Condition Control Using Coupled DEM–FDM

2021 ◽  
Vol 11 (6) ◽  
pp. 2551
Author(s):  
Hyobum Lee ◽  
Hangseok Choi ◽  
Soon-Wook Choi ◽  
Soo-Ho Chang ◽  
Tae-Ho Kang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Large Scale ◽  
Tunnel Boring Machine ◽  
Chamber Pressure ◽  
Screw Conveyor ◽  
Shield Tunnel ◽  
Pressure Balance ◽  
Operational Conditions ◽  
Shield Tunnelling ◽  
Epb Shield

This study demonstrates a three-dimensional numerical simulation of earth pressure balance (EPB) shield tunnelling using a coupled discrete element method (DEM) and a finite difference method (FDM). The analysis adopted the actual size of a spoke-type EPB shield tunnel boring machine (TBM) consisting of a cutter head with cutting tools, working chamber, screw conveyor, and shield. For the coupled model to reproduce the in situ ground condition, the ground formation was generated partially using the DEM (for the limited domain influenced by excavation), with the rest of the domain being composed of FDM grids. In the DEM domain, contact parameters of particles were calibrated via a series of large-scale triaxial test analyses. The model simulated tunnelling as the TBM operational conditions were controlled. The penetration rate and the rotational speed of the screw conveyor were automatically adjusted as the TBM advanced to prevent the generation of excessive or insufficient torque, thrust force, or chamber pressure. Accordingly, these parameters were maintained consistently around their set operational ranges during excavation. The simulation results show that the proposed numerical model based on DEM–FDM coupling could reasonably simulate EPB driving while considering the TBM operational conditions.

scholarly journals Comparative analysis of methods to determine deflection in steel beams: theoretical analysis, finite element and experimental

2020 ◽  
pp. 32-37
Author(s):  
Gabriela Alor-Saavedra ◽  
Francisco Alejandro Alaffita-Hernández ◽  
Beatris Adriana Escobedo-Trujillo ◽  
Oscar Fernando Silva-Aguilar
Keyword(s):  
Differential Equation ◽  
Experimental Data ◽  
Finite Element ◽  
Comparative Analysis ◽  
Theoretical Analysis ◽  
Comparative Study ◽  
Steel Beams ◽  
Physical Systems ◽  
Theoretical Part ◽  
Made In

This work makes a comparative study of two methods to determine deflection in steel beams: (a) Theoretical and (b) Finite element. For method (a) the solution of the differential equation associated with the modeling of the deflection of a beam is found, while for method (b) a simulation is made in Solidworks. Both methods are compared with experimental data in order to analyze which of the methods presents less uncertainty and show the usefulness of the theoretical part in the modeling of physical systems.

scholarly journals Numerical Simulation of a Textured and Untextured Photovoltaic Solar Cell: Comparative study

2021 ◽  
Vol 03 (01) ◽  
pp. 104-114
Author(s):  
Karim Salim ◽  
◽  
M.N Amroun ◽  
K Sahraoui ◽  
W Azzoui ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Solar Cells ◽  
Solar Cell ◽  
Comparative Study ◽  
Silicon Solar Cell ◽  
The Other ◽  
Surface Parameters ◽  
Cell Efficiency ◽  
Photovoltaic Solar Cell ◽  
A Cell

Increasing the efficiency of solar cells relies on the surface of the solar cell. In this work, we simulated a textured silicon solar cell. This simulation allowed us to predict the values of the surface parameters such as the angle and depth between the pyramids for an optimal photovoltaic conversion where we found the Icc: 1.783 (A) and Vco: 0.551 (V) with a cell efficiency of about 13.56%. On the other hand, we performed another simulation of a non-textured solar cell to compare our values and found Icc: 1.623 (A) and Vco: 0.556 (V) with an efficiency of about 12.76%.

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