scholarly journals Vibrations induced by Tunnel Boring Machines in urban areas: dataset of synchronized in-situ measurements inside the shield and on the surface.

Data in Brief ◽  
2022 ◽  
pp. 107826
Author(s):  
Antoine Rallu ◽  
Nicolas Berthoz
2020 ◽  
Vol 61 (1) ◽  
pp. 31-40
Author(s):  
Do Ngoc Thai ◽  
Do Duc Toan ◽  

In the mechanized excavation of subway tunnels, the shield tunnel boring machine (TBM) has been developed in recent decades for managing the instability of the excavation profile in complicated geotechnical conditions in urban areas. The paper presents a 3D simulation procedure for the detailed description of TBM (via the finite element code Abaqus) and quantifies the influence of TBM face pressure on ground surface settlements. The model is used to calculate ground surface settlements for different values of TBM face pressure. An additional aspect of the investigation is the determination of the critical value of TBM face pressure, which controls face instability in very weak ground. During the advancement of shield tunnel boring machines, the face-stabilizing pressure is one of the most important factors of critical. In tunneling by shield tunnel boring machines, high face pressure often leads to surface upheaval, whereas low face pressure leads to sudden collapse of the face and ultimately settlement of the surface. For the model condition, the maximum value was quantity 250 kPa and the minimum value obtained quantity 150 KPa.


Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 368
Author(s):  
Lisdelys González-Rodríguez ◽  
Amauri Pereira de Oliveira ◽  
Lien Rodríguez-López ◽  
Jorge Rosas ◽  
David Contreras ◽  
...  

Ultraviolet radiation is a highly energetic component of the solar spectrum that needs to be monitored because is harmful to life on Earth, especially in areas where the ozone layer has been depleted, like Chile. This work is the first to address the long-term (five-year) behaviour of ultraviolet erythemal radiation (UVER) in Santiago, Chile (33.5° S, 70.7° W, 500 m) using in situ measurements and empirical modelling. Observations indicate that to alert the people on the risks of UVER overexposure, it is necessary to use, in addition to the currently available UV index (UVI), three more erythema indices: standard erythemal doses (SEDs), minimum erythemal doses (MEDs), and sun exposure time (tery). The combination of UVI, SEDs, MEDs, and tery shows that in Santiago, individuals with skin types III and IV are exposed to harmfully high UVER doses for 46% of the time that UVI indicates is safe. Empirical models predicted hourly and daily values UVER in Santiago with great accuracy and can be applied to other Chilean urban areas with similar climate. This research inspires future advances in reconstructing large datasets to analyse the UVER in Central Chile, its trends, and its changes.


Author(s):  
Tobias Rahm ◽  
Kambiz Sadri ◽  
Christian Koch ◽  
Markus Thewes ◽  
Markus Konig

2018 ◽  
Vol 8 (10) ◽  
pp. 1877 ◽  
Author(s):  
Yong Hu ◽  
Jiyu Tian ◽  
Mingxu Xu ◽  
Hongwei Zhao ◽  
Mingze Wang ◽  
...  

The material of disc cutters is important to full-face tunnel boring machines (TBM). In recent years, disc cutters were optimized and tested by many scholars all around the world. H13(4Cr5MoSiV1) steel is widely used due to its excellent properties, especially in TBM disc cutters. In this paper, H13 steel with optimized composition was prepared and heat treatment. The high temperature compression of H13 steel was conducted at the temperatures ranging from 100 °C to 700 °C, with strain rate at 0.01 s−1. The stress-strain curves, Rockwell hardness and microstructure of H13 steel after compression were obtained and analyzed. The results showed that the compression strength and hardness decreased as the temperature increased; and the compression strength, hardness and ductility decreased rapidly between 600 °C and 700 °C, HR700 (the hardness of H13 steel at 700 °C) only reached 33.23 HRC. It is not recommended for TBM disc cutters to work in an environment over 600 °C.


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