फरक पाना| Zircon Creations

Tunnel forepoling (forepoles) Tunnel forepoling (forepoles) refers to the placement of near-horizontal steel bars/pipes/sections around the periphery of the heading to form a rock support cage in weak zone areas. To support the excavation roof or tunnel crown, in other words. Forepoling should be used on rock and soil conditions that are prone to overbreak, collapses, or material inflow immediately after the following excavation. It shall be applied locally or systematically, depending on the circumstances, for the safety of the works and the prevention of overbreak. According to Warner forepolling should be densely installed to reduce the influences from stress-release at the face and the crown. Face bolts only contributed to stress-release at the face. Forepolling divides the surrounding ground of the installed area into two zones; i) outside the zone of the invisible arch consisting of forepoles and ii) inside the zone of the forepoles. Forepoles, by definition, have a larger diamet...

Which are the best tunnel construction methods? Tunnel construction methods include drill and blast, shield, cut and cover, tunnel boring machine (TBM), New Austrian Tunneling Method (NATM), also known as Sequential Excavation Method (SEM), road header, sunken tube, and jack. The more important question is how to figure out which method is best for a particular project. The selection of tunnel construction methods is influenced by a variety of factors ranging from geological to economic to sociological. Because ground conditions such as whether the tunnel passes through rock, soil, or mixed ground can drive the construction method decision, because some methods are more efficient in certain ground conditions, geological factors frequently affect economic considerations. Shallow tunnels are frequently built using cut and cover techniques, particularly in urban areas. Tunnels that cross bodies of water can be bored or built with sunken tubes, depending on the depth of the water, ground c...