Project: Bechtel / Cheniere Liquefaction
Location: Corpus Christi, TX
Asset: 60-inch product transfer line, road crossing at plant main entrance
CHALLENGE
A pipeline contractor drove sheet piles and excavated a bore pit roughly 20 ft deep to install a 60-inch product transfer line beneath the road near the plant's main entrance. The bore pits were about 100 LF apart. As the cutting head advanced on the pilot hole, groundwater began infiltrating the pit at an extremely high flow rate. High-volume trash pumps could not keep the pit dewatered, and boring was suspended.
SOLUTION
Superior Grouting was selected to seal the surrounding soil and cut off the water inflow using permeation grouting through the existing sheet piles. A grid of 5/8-inch holes was cut through the sheet pile across the face wall and both side walls. A 12-inch injection probe was pushed into the soils and Avanti AV-100 was injected to permeate the soil fines and reduce the soil's permeability. The sequence was repeated area by area, from the bottom up. As the injection progressed, water infiltration dropped steadily to a manageable rate.
RESULTS
Water infiltration was reduced to a manageable flow, allowing the contractor to bore the 60-inch hole and pull the pipe.
The work was completed on time and the project stayed on schedule.
