Advanced Construction Techniques was awarded this project by the U.S. Army Corps of Engineers of Nashville District. The project was considered the number one top priority remediation structure in the nation.
The scope of work consisted of a double line grout curtain to depths of 330 ft within the limestone foundation material. The purpose of the project was to reduce the residual permeability of the dam foundation as a pre-treatment for the proposed cutoff wall contract. This work also required construction of a 4,000 ft long work platform and environmental collection and treatment ponds to support the drilling and grouting work.
Work included embankment overburden drilling and installation of permanent casing up to depths of 180 ft seated into the embankment rock interface utilizing sonic drilling methods. Continuous sampling and logging of the embankment material was performed to determine clay core integrity. Site characterization was determined by exploratory drilling using rotary diamond core drilling with continuous sampling and logging of rock cores, pressure water testing and video imaging. Foundation rock drilling was performed with water actuated down the hole hammer followed by borehole washing, permeability testing and pressure grouting using balanced stable high mobility grouts. Special procedures and grout mixes were developed to treat karst solution features encountered within the rock foundation. Gallery drilling and grouting using rotary diamond drilling, water flush, permeability testing and pressure grouting was also required.
IntelliGrout®, a proprietary computer monitoring system was utilized for real-time electronic monitoring and recording of the permeability testing and grouting.
Client: US Army Corps of Engineers, Nashville District
Owner: US Army Corps of Engineers, Nashville District