Modeling of soil movement in the screw conveyor of the earth pressure balance machines (EPBM) using computational fluid dynamics

2015 ◽  
Vol 47 ◽  
pp. 136-142 ◽  
Author(s):  
Kaveh Talebi ◽  
Hossein Memarian ◽  
Jamal Rostami ◽  
Ehsan Alavi Gharahbagh
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Earth Pressure ◽  
Screw Conveyor ◽  
Pressure Balance ◽  
Soil Movement ◽  
The Earth ◽  
Earth Pressure Balance

scholarly journals Earth pressure balance control of shield tunneling machine based on nonlinear least squares support vector machine model predictive control

2018 ◽  
Vol 52 (1-2) ◽  
pp. 3-10 ◽  
Author(s):  
Xuanyu Liu ◽  
Kaiju Zhang
Keyword(s):  
Support Vector Machine ◽  
Least Squares ◽  
Balance Control ◽  
Earth Pressure ◽  
Screw Conveyor ◽  
Support Vector ◽  
Pressure Balance ◽  
Machine Model ◽  
The Earth ◽  
Earth Pressure Balance

Background: Earth pressure balance shield machines are widely used in underground engineering. To prevent ground deformation even disastrous accidents, the earth pressure in soil chamber must be kept balance to that on excavation face during shield tunneling. Therefore, in this paper an advanced control strategy that a least squares support vector machine model-based predictive control scheme for earth pressure balance is developed. Methods: A prediction model is established to predict the earth pressure in chamber during the tunneling process by means of least squares support vector machine technology. On this basis, an optimization function is given which aims at minimizing the difference between the predicted earth pressure and the desired one. To obtain the optimal control actions, an improved ant colony system algorithm is used as rolling optimization for earth pressure balance control in real time. Results: Based on the field data the simulation experiments are performed. The results demonstrate that the method proposed is very effective to control earth pressure balance, and it has good stability. Conclusion: The screw conveyor speed and advance speed are the major factors affecting the earth pressure in chamber. The excavation face could be controlled balance better by adjusting the screw conveyor speed and advance speed.

Earth pressure balance control for shield tunneling machine based on adaptive dynamic programming

2020 ◽  
Vol 42 (13) ◽  
pp. 2440-2449
Author(s):  
Xuanyu Liu ◽  
Sheng Xu ◽  
Kaiju Zhang
Keyword(s):  
Cost Function ◽  
Balance Control ◽  
Earth Pressure ◽  
Screw Conveyor ◽  
Pressure Balance ◽  
The Earth ◽  
Gradient Descent Algorithm ◽  
Action Network ◽  
Earth Pressure Balance ◽  
Cutter Head

In order to avoid the safety accidents caused by earth pressure imbalance during shield machine tunneling process, the earth pressure between excavation face and that in chamber must be maintained balance, but it is difficult for practical engineering. Therefore, a data-driven multi-variable optimization method based on dual heuristic programming (DHP) is proposed. First, a cost function with respect to the chamber’s earth pressure is given in light of Bellman’s principle. Then, based on back propagation neural networks (BPNN), the action network, model network and critic network are established that compose the DHP controller. The networks’ weights are updated through the gradient descent algorithm. By minimizing the cost function, the action network utilizes the critic network’s error to optimize the control variables, so that the optimal advance speed, cutter head torque, cutter head speed, total thrust and screw conveyor speed are obtained. Finally, the simulation experiments are carried out, and the results indicate that the method can effectively control the earth pressure balance in chamber and has strong anti-interference ability.

Predicted versus measured soil movements induced by shield tunnelling in the Madrid Metro extension

2005 ◽  
Vol 42 (4) ◽  
pp. 1160-1172 ◽  
Author(s):  
Manuel Melis Maynar ◽  
Luis Medina Rodriguez
Keyword(s):  
Numerical Model ◽  
Numerical Modelling ◽  
Earth Pressure ◽  
Pressure Balance ◽  
Ground Movements ◽  
The Earth ◽  
Shield Tunnelling ◽  
Earth Pressure Balance ◽  
Numerical Modelling And Analysis ◽  
Soil Movements

A detailed study on the available methods of predicting ground movements due to tunnelling works was carried out during the construction of the Madrid Metro extensions in 1995–1999 and 1999–2003. A total of 100 km were built and commissioned during this period. A numerical model was developed to simulate the earth pressure balance (EPB) excavation procedure and to complement some of the deficiencies found in previous analytical or empirical subsidence estimation procedures. Before the beginning of the works, a total of six different methods were used to estimate ground movements generated by the tunnelling works at some monitored sections placed in all five cities linked by the 1999–2003 extension, and the estimations were published in an earlier paper in this journal. Once all tunnelling works were finished and actual measurements carried out, a number of comparisons between predictions and measurements were made and are included in this paper. Conclusions about the applicability and accuracy of the methods are established with the aim of helping researchers and engineers in their future projects.Key words: ground movements, monitoring, numerical modelling and analysis, settlement, tunnels.

Prediction and analysis of subsidence induced by shield tunnelling in the Madrid Metro extension

2002 ◽  
Vol 39 (6) ◽  
pp. 1273-1287 ◽  
Author(s):  
Manuel Melis ◽  
Luis Medina ◽  
José M Rodríguez
Keyword(s):  
Earth Pressure ◽  
Tunnel Construction ◽  
Pressure Balance ◽  
Ground Movements ◽  
Construction Methods ◽  
The Earth ◽  
Predictive Methods ◽  
Shield Tunnelling ◽  
Earth Pressure Balance ◽  
Numerical Modelling And Analysis

The development of tunnelling projects under heavily populated cities has been rapidly increasing around the world during the last decades. Since tunnel construction can have disastrous effects on buildings, structures, and utilities near the excavation, construction methods have necessarily to provide maximum safety inside and outside the tunnel. To predict and correct dangerous ground movements due to the tunnelling works, the authors developed a numerical model to simulate the earth pressure balance (EPB) excavation procedure and injection to complement some deficiencies found in previous analytical or empirical subsidence estimating procedures. This model takes into account the full excavation sequence and has been validated by a large amount of monitoring data from the previous Madrid Metro extension. In the present paper, several predictive methods are used to predict the ground movements generated during a new Madrid Metro extension project consisting of 48 km of tunnel (1999–2003). At the end of the works the results will be compared with data from monitored sections placed in all five cities linked by the extension. Conclusions about the applicability and accuracy of the methods will be established with the aim of helping researchers and engineers in their future projects.Key words: ground movements, monitoring, numerical modelling and analysis, settlement, tunnels.

Shield’s EPB Simulation Device Based on Fluid Power Transmission Principle

2011 ◽  
Vol 480-481 ◽  
pp. 745-750
Author(s):  
Xiao Li ◽  
Xiao Jiang Su
Keyword(s):  
Power Transmission ◽  
Effective Means ◽  
Earth Pressure ◽  
Mathematic Model ◽  
Fluid Power ◽  
Screw Conveyor ◽  
Hydraulic Parameters ◽  
Pressure Balance ◽  
Scheme Design ◽  
Earth Pressure Balance

This article presents a shield’s earth-pressure-balance (EPB) simulation device based on fluid power transmission principle. The device was developed according to the mathematic model of shield’s EPB system. It is composed of load simulation subsystem and screw-conveyor speed control subsystem. With the regulations of the hydraulic parameters in the subsystems, the device is capable of simulating the situations of earth input and output in cutter chamber, as well as the changes of earth property and shield propulsive velocity. Experimental results proved that the working principle of the device is right, the regulation of hydraulic parameters is convenient, and the enhancement of experiment strength is feasible. Therefore, the experiment research expense on shield's EPB system is reduced and the experiment efficiency is increased. The developed device can provide an economical and effective means for the scheme design and characteristics analysis of shield's EPB system.

Performance Simulation Analysis and Design of the Scale Model for the Earth Pressure Balance Shield

2011 ◽  
Vol 346 ◽  
pp. 364-371 ◽  
Author(s):  
Xu Chen ◽  
Zhu Feng Shao ◽  
Xiao Qiang Tang ◽  
Ping Fa Feng
Keyword(s):  
Optimization Design ◽  
Driving Forces ◽  
Simulation Analysis ◽  
Earth Pressure ◽  
Scale Model ◽  
Pressure Balance ◽  
Analysis And Design ◽  
The Earth ◽  
Earth Pressure Balance ◽  
Epb Shield

Referring to the Earth Pressure Balance (EPB) shield with the diameter of 6.25m, a new experiment station of EPB shield is proposed, which is loaded with mechanical structure instead of traditional soil box. The structure of the experiment model is designed for the performance analysis of the EPB shield. The mechanical loading device, which is called the soil simulator, can simulate different geological environments. The soil simulator is capable of realizing three work states, such as earth balance pressure, earth under pressure, and earth over pressure. By adopting virtual prototype technology, parametric model of the shield station is established and the co-simulation scheme is determined. Besides, the kinematic analysis as well as variation principles between the displacement and driving forces of the propulsion system are obtained, which build the foundation for optimization design and control of the shield prototype.

scholarly journals A New Soil Conditioner for Highly Permeable Sandy Gravel Stratum in EPBs

2021 ◽  
Vol 11 (5) ◽  
pp. 2109
Author(s):  
Xin Lin ◽  
Xiong Zhou ◽  
Yuyou Yang
Keyword(s):  
Earth Pressure ◽  
Coarse Grained ◽  
Screw Conveyor ◽  
Plastic Behavior ◽  
Pressure Balance ◽  
Soil Conditioner ◽  
Sandy Gravel ◽  
Ground Collapse ◽  
Earth Pressure Balance ◽  
Full Face

Full-face water-rich gravel stratum is a large challenge during tunnel excavation with earth pressure balance shields (EPBs) because of accidents such as water spewing from the screw conveyor and ground collapse. Slurry and polymer have been used as conditioning agents to avoid such problems and thus ensure a successful tunneling. However, limited improvement of sandy gravel was achieved when traditional soil conditioner were applied. This study proposes a new conditioner (modified slurry) consisting of bentonite slurry, viscosity modifier, sodium silicate and polymer, which will enhance the properties of sand gravel stratum. Low reaction time, high apparent viscosity, good plastic behavior and low permeability were employed for investigating the optimum ratio of the ingredients. The proposed modified slurry has a good performance in conditioning sandy gravel soils and can be the reference for EPBs’ excavation in highly permeable, non-adhesive coarse-grained soil stratum.

scholarly journals Study on the Mechanical Characteristics of the Screw Driving Torque during the Emptying of the Shield Soil Bin

2021 ◽  
Vol 2101 (1) ◽  
pp. 012004
Author(s):  
Xingchun Li ◽  
Yi Yang ◽  
Xinggao Li ◽  
Weilin Su ◽  
Zhi Liu ◽  
...  
Keyword(s):  
Earth Pressure ◽  
Screw Conveyor ◽  
Model Parameters ◽  
Pressure Balance ◽  
Negative Exponential Function ◽  
Earth Pressure Balance Shield ◽  
Earth Pressure Balance ◽  
Negative Exponential ◽  
Soil Bin ◽  
Driving Torque

Abstract This article studies the changing law of the driving torque of the screw conveyor during the emptying process of the earth pressure balance shield chamber. First, the discrete element method of discrete medium theory and 3D software SolidWorks were used to create the research object and the screw conveyor model, and then the model parameters were determined and calibrated through numerical calculations and indoor experiments. The final numerical calculation results show that: 1) the screw torque will drop in waves with the increase of the calculation time. When the screw conveyor rotates at 360 deg/s, the calculated screw torque fluctuation amplitude is small; 2) when the number of particles in the soil bin is reduced to a certain extent, the use of a higher screw speed to improve the “dumping soil effect” is of little significance; 3) the negative exponential function can be used to better fit the decrease of screw torque with time; 4) for the bulk medium, for a given particle size and screw structure, there is a suitable speed, so that the effect of “machine-soil collision” is small, and the torque change of the screw is relatively stable.

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