Brayman was contracted to provide specialty construction services in order to upgrade the stability of Bluestone Dam, located on the New River in Summers County, WV.
This project involved the installation of 212 high capacity rock anchors, ranging from six to 61 strands, to upgrade the stability of the existing dam. With rock anchors as deep as 275′ and the close proximity of adjacent anchors, drill tolerances of 1:150 were required so that the rock anchors did not intersect embedded items in the dam or other anchors. Brayman utilized directional drilling techniques to satisfy such tolerances. The project also included the design and construction of two temporary soil nail walls, excavation and placement of 13,000 cy of embankment along with the installation of three penstock extensions utilizing mass concrete and hydraulically operated bulkhead gates.
Brayman erected 780 lf of steel platform bridge across the spillway to support anchor operations. The platform was able to support two 85-ton crawler cranes in addition to multiple drill rigs and other support equipment.
Gallery work included cleaning 275 existing drains by enlarging the drain diameters 1/4”. This was accomplished by reaming the entire length of the drains (+16,000 lf). Installation of 40 new relief drains was accomplished by core drilling to depths up to 120’. Vibrating wire piezometers were also installed at eight of these locations. As the gallery only measures 6’ wide by 8’ tall at peak, the tight space offered a challenge for the drilling team.
Apron work was performed from barges located in the stilling basin downstream of the dam. Existing relief drains tied to a drainage network were extended up to 25’ at 49 locations. Divers located the existing drain holes and verified the installation angle. As the sluice gates for the dam remained active, the schedule for the stilling basin was created, keeping the barges away from all open gates.