Optimizing the performance of the EPB Tunnel Boring Machine of Isfahan metro line 2 against wear and material transfer based on the adaptability of the machine to the project ground with the help of the numerical modeling in EDEM software

Rasekh, Erfan; Lotfi, ِDavood

Optimizing the performance of the EPB Tunnel Boring Machine of Isfahan metro line 2 against wear and material transfer based on the adaptability of the machine to the project ground with the help of the numerical modeling in EDEM software

Document Type : Original Article

Authors

Erfan Rasekh ¹
ِDavood Lotfi ²

¹ Amirkabir university of Tehran

² Tunnelsaz Machine

Abstract

In this article, for the first time in Iran, by using discrete element Method analysis, the main weaknesses in the excavation of Isfahan metro line 2 using EPB drilling machine were identified and practical solutions were proposed to solve it. The machine geometry was modeled and imported into the EDEM discrete element software for the second part of the analysis. The parameters of the tunnel lining, soil and conditioned soil were calibrated using the laboratory data set of sieve analysis test, direct shear test and slump.The results showed that the lower third of the chamber and the enclosed area between the arms of the device have a high clogging potential and the particles have a weak velocity field in this area. Two optimization plans were presented with the help of installing a new mixing bar on the cutterhead, and the results showed that the second plan, where the mixing bar is installed on the arm of the cutterhead, a significant improvement in the speed of the particles happens, and the average speed of the particles in the central region sometimes improves up to 5 times. First optimization plan one did not work well and only partially improved the particle velocity field. As another solution to optimize and improve the particle velocity field in the lower third of the chamber space, the use of waterjet rows was suggested, and with the help of software, the critical area was identified and the best place to install waterjet lines was determined.

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