Over the past 25 years Gibson has been involved in many tunnel grouting projects across the Southeastern United States. No tunnel is too small, or too big. Gibson has worked on small diameter structures (96 inch dia.) up to TBM structures (28 feet dia.). There are many different forms of “tunnel grouting”, but some specific process descriptions include: annular space grouting, host to carrier void fill, re lines, liner plates, contact grouting, rock void grouting , hydrophobic grout injection for water control, etc.