During underground construction, the behavior of ground is influenced by characteristics rock mass with situ stresses and water, cross section excavation area, method, rate excavation. These fundamental features are considered to ensure support stability excavations achieve long-term successful operation. However, composition Himalayas hinders tunnel excavation, especially in case mechanized tu...

This study uses numerical modeling in combination with rock mass classification approaches to develop tunnel support systems that are safe from earthquakes, ultimately contributing the seismic resilience of important infrastructure. A case Himalayan region Nepal has been considered for assessment supports different geological conditions. For better quality masses (GSI>30), strain-softening m...

Elastic solutions applicable to single underground openings usually suffer from geometry related simplification. Most tunnel shapes possess two axes of symmetry while a wide range of geometries used in tunneling practice involve only one symmetry axis. D-shape or horse-shoe shape tunnels and others with arched roof and floor are examples of the later category (one symmetry axis). In the present...

Personal 8-h shift exposure to respirable dust, diesel engine exhaust emissions (DEEE) (as respirable elemental carbon), and respirable crystalline silica of workers involved in constructing an underground metro railway tunnel was assessed. Black carbon (BC) concentrations were also assessed using a MicroAeth AE51. During sprayed concrete lining (SCL) activities in the tunnel, the geometric mea...

Muon radiography is an innovative and non-destructive technique for internal density structure imaging, based on measuring the attenuation of cosmic-ray muons after they penetrate target. Due to strong penetration ability muons, detection range muon can reach order hundreds meters or even kilometers. Using a portable detector composed plastic scintillators silicon photomultipliers, we performed...

A thickness variation of only one Ångström makes a significant difference in the current through a tunnel junction due to the exponential thickness dependence of the current. It is thus important to achieve a uniform thickness along the barrier to enhance, for example, the sensitivity and speed of single electron transistors based on the tunnel junctions. Here, we have observed that grooves at ...