TenCate Geosynthetics Americas Pendergrass, GA
Producer: TenCate Geosynthetics
Engineer Company 1
Public-Private Partnership (P3): INDOT/Isolux Corsan/Indiana Financial Authority (IFA)
Crider & Crider, Inc.
Project Manager Company
Crider & Crider, Inc.
Please describe the project specifications
This is a section of a new connector road circumventing a new interchange as part of the INDOT I-69 Section % P3 Project. The connector road is part of the Liberty Church Road Interchange and was constructed through a corn field. The water table was approximately two (2) feet below grade. The connector road construction required 3 – 5 feet of engineered fill be placed to achieve the plan subgrade elevation, then paved with a flexible pavement.
This project involved a single layer of Mirafi® H2Ri geosynthetic with 16 inches of a silty sand (A-2) fill.
What was the purpose of this project? What did the client request?
The earthwork contractor cut the topsoil along the proposed connector road route and began placing silty sand, engineered fill. Due to the high water table and as a result of compaction energy and trafficking, water was migrating up into the engineered fill, resulting in rutting and displacement of the fill. The contractor initially intended to utilize a geogrid or other reinforcing geotextile to stabilize and reinforce the fill. Due to the high water table and the resulting effect of the water on the fill, TenCate Geosynthetics suggested utilizing Mirafi® H2Ri reinforcing geosynthetic with water wicking capability. The initial 600 lineal feet x 45 feet wide was installed as a test section. The contractor desired a product that would stabilize the section, allowing the engineered fill to be placed to planned subgrade elevation and subsequently paved.
What is unique or complex about the project?
The challenging aspect of this application was the water. With the ground water table so close to existing grade (within two (2) feet), a standard reinforcing geosynthetic would not be very effective unless the water could be removed. Typical reinforcing geosynthetics would require temporarily lowering the water table via a dewatering system, or installing some kind of drainage system (French drains, drainage composite, etc.) to remove the water as it migrates up into the fill. In addition to possessing separation, filtration, confinement and reinforcement functions, the Mirafi H2Ri also has a wicking capability. The technology works through a pressure differential mechanism and literally siphons/absorbs water into the specialized wicking fibers and carries the water (without releasing back into the subgrade) to the outside edge, in this case released to an open ditch along the roadway. By preventing the water from migrating up into the engineered fill, the reinforcing and confinement functions of the geosynthetic perform as desired, reinforcing and stabilizing the engineered fill.
What were the results of the project?
TenCate Mirafi H2Ri enabled installation of the engineered fill without having to utilize a dewatering system to temporarily lower the water table during placement of the fill, nor installing a French drain system or drainage composite. All of which would have cost more and taken more time off the schedule. The H2Ri continues to be used on the project where subgrade reinforcement and water are an issue.
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