3.7 Insertion of Rock bolts

•A Rock Bolt is a long Anchor bolt for stabilising rock excavations. A rock bolt transfers the load from unstable exterior to confined interior of rock mass.
•Two types of Rock Bolts are used in Rohtang Tunnel:

    1) Swellex Mn24

     As the name suggests, Swellex swells when water pressure is applied at its opening. It anchors large broken Rocks.

    2) Injection Bolt

    Injection bolt is a hollow steel tube of 35mm dia provided with holes

    of diameter 5mm throughout its length. When cement is grouted through

   Injection bolt, the grout is released from these holes are broken pieces of

   are bound together.