AULtec, Inc. has provided services in subterranean or underground tunneling surveying/support services in various challenging situations for the Washington Suburban Sanitary Commission (WSSC) 5.34-mile Bi-County Water Tunnel in Montgomery County, Maryland.
Existing ground Horizontal and Vertical Controls were checked for accuracy and consistency at various shaft sites and transferred approximately 150 feet underground by way of the shafts. Transferred controls were then extended into the tunnel, checked and validated for use by the Tunnel Boring Machine (TBM).
Wall monitoring prisms and inclinometers were checked on a consistent schedule for movement and spreadsheets provided.
Vaults and air release Manholes were staked and as-built as required.
Strict required horizontal and vertical accuracies were attained for the smooth operation of the TBM.
AULtec, Inc., also provided various above-ground and underground support services for the general contractor.
