Crux provided drilling and installation services for drain wells and piezometer borings. Angle-oriented borings and drain-holes were drilled from the tunnel level, working within 10-foot diameter access tunnels.
Borings and drain-holes were completed under tight tolerances and through soft sedimentary rock. Surveys of the borehole were completed during drilling operations, and borings maintained a maximum deviation of 18 inches in each axis throughout the length of the boring. Core drilling was employed for drilling geotechnical and piezometer borings. Rotary wash drilling was employed for drain-holes. In total, 5 piezometers and 21 drain wells were installed, with depths ranging from 100 to 350 feet. Stainless steel casing was installed at each piezometer and drain-hole location.