Patent ID: 7654777

Claim:
A grout pack restraining system, comprising a plurality of elongate elements shaped to extend about a grout pack having an initial size to control circumferential expansion of the grout pack, the elongate elements including: (a) a first ring having a first diameter in an unyielded condition, the first diameter sized to restrain the grout pack at its initial size, and a second diameter at a maximum design yield, the second diameter being significantly greater than the first diameter; and (b) a second ring supported relative to the first ring; (c) wherein the second ring has, in an unyielded condition, a third diameter which is significantly greater than the first diameter and substantially equal to or less than the second diameter, such that, in response to expansion of the grout pack which causes yielding of the first ring, the second ring will provide restraint to the grout pack prior to failure of the first ring, thereby providing a progressive yield of the grout pack.