390 Times and Not One Failure
After completing 65 borings in stiff- to medium-stiff clay, GeoServ, using their faithful 6620DT, was able to provide complete sample recovery using the DT22 system coupled with Genuine Geoprobe® liners with an integrated core catcher.
Filled DT22 soil core liners recovered by GeoServe using Geoprobe® liners and a 6620DT. The integrated core catchers in the liners (shown at end of each liner) keeps the sample from falling out the bottom of the liner as the core is retracted.
According to Dean Govan, Environmental Geologist and President of GeoServ in New Hudson, MI, “The core catcher was a critical component to the success of the project, providing 100 percent sample retention during the retrieval of the liner after advancement.”
The soil encountered during the investigation was a medium-stiff clay. Because of the nature of the formation (expanding clay), it was necessary to only advance half push between liner retrieval. In many cases, 5 feet of soil was recovered with a 2.5-ft. push. Dean said 100 percent sample retrieval was obtained in all 390 soil cores recovered. “Not one time during the duration of the project did we experience sample loss of the stiff clay,” he said. “In the past, we’ve experienced problems with a portion of the soil core being left downhole using aftermarket liners fitted with core catchers or using liners without a core catcher.” This caused delays or incomplete contaminant delineation for the GeoServ team. The only lack of sample recovery occurred from the occasional rock encountered which was easily overcome by pushing a solid point to displace the rock from the cutting shoe.
Dean summed up the work: “The consistency in the quality of the Genuine Geoprobe® product for the entire duration of this project was very impressive to me and was one of the many key pieces that made this project go so well! This is the level of quality we have come to expect from Geoprobe®, and it’s what GeoServ strives for in our services – a good partnership!”