Expansion shell anchor bolts are a common style of area ground support.There is an expansion shell
at the end of the bolt which is inserted into the hole. As the bolt is tightened by the installation drill the expansion shell expands and the bolt tightens holding the rock together. Mechanical bolts are
considered temporary support.
The expansion units have exclusive features that ensure positive anchorage under the most conditions.
The expansion units, which are available in many variations, conforms to the hole diameter. This ensures a even load distribution between the anchor and the rock at the anchor point.