National Driller magazine recently republished a paper by authors from GRL Engineers Inc. and Pile Dynamics Inc. (PDI) describing a demonstration project for the Texas Department of Transportation involving thermal integrity profiling (TIP) of soil nails. TIP involves using the thermal energy created by curing concrete to determine the shape of a grout or concrete body and the position of reinforcement within a grouted or concreted hole. It has been used successfully for QC of drilled shafts and auger cast piles. It can be performed in open access ports by lowering a thermal probe down the hole, or by attaching thermal wire cables to the reinforcement with sensors spaced every 6 inches. This study used the thermal wire cables attached to two soil nail bars grouted into 6 inch diameter holes. The first nail had no deliberate defects, the second had two intentional soil inclusions attached to the bar prior to grouting. The TIP successfully identified the anomalies and it appears that the method shows potential for QC of the shape and diameter of a grout body around a soil nail. [Source: Read the article at National Driller. Image: National Driller]
Related Articles
Side Hill Retaining Walls – Part 2
In this part 2 of 2, various types of retaining walls are examined as possible alternatives in a side-hill retaining wall situation. These include conventional wall types such as CIP walls, MSE walls, gravity walls and soldier pile walls and some less conventional approaches such as lighweight concrete fill, hybrid soil-nail and geofoam wall systems, ground improvement and micropile walls.
Part 1 of this Side Hill Retaining Wall article covered the definition, significance, problems and failure modes, investigation techniques, analysis, and construction considerations of side hill walls. A PDF version is now available for download as well. Click through for the article and the download link!
Updated – DFI Committee Looking for Soil Nail Data
[Update 2008-06-25 8am] I saw somewhere that they were looking for this info by July 1, but I don’t know where. I couldn’t find a deadline on the DFI Committee page. Maybe they erased it. [/Update]
The Tiebacks & Soil Nailing Committee of the Deep Foundations Institute is collecting data on soil nail wall performance. From the Tiebacks & Soil Nailing Committee page:
A request for information has been distributed to all DFI members, academia and various other industry members. Information being sought includes typical project, geotechnical and wall geometry information, design and analysis methods and software, construction and monitoring duration, settlement and lateral deformation data, and nail strain gauge data. Click here to download the PDF form to enter your project’s information to the committee for compilation and analysis.