Abstract: A barrier for use with a rod extending into a bore having a cross sectional dimension, formed in a structure. The barrier is located on one side of a fluid supply in the bore. The barrier includes a sealing portion adjacent the fluid supply, the sealing portion has a flexible flange in sealing contact with the bore. A tube is connected to the sealing portion and has a rod passageway formed there through. A diameter of the tubular portion is smaller than the cross sectional dimension prior to insertion of the rod, and expands to conform to the cross sectional dimension in response to insertion of the rod. A rupture portion is connected to the tubular portion, and seals the rod passageway to limit a passage of fluid therethrough prior to insertion of the rod. The rupture portion is adapted to rupture in response to penetration by the rod. The barrier may be used in conjunction with a dynamic earth anchor, to prevent passage of the grout to between the anchor and the bore.