The site for the new Harrison County Hospital, approximately 25-miles west of Louisville, Kentucky had 15 sinkholes formed by limestone dissolution, a geomorphologic process referred to as Karst topography. There were a number of geotechnical engineering and geological engineering challenges associated with the characterization, excavation, backfilling, foundation engineering and other mitigation measures as described by Peggy Hagerty Duffy, P.E. in her article entitled “Karst and Complications” in the August 2008 issue of Civil Engineering Magazine (Duffy, 2008b).
Mitigation measures for the sinkholes included use of graded filters with geotextiles, careful inspection of rock socket foundations along with pilot holes and careful geotechnical inspection throughout the construction process. One particularly interesting aspect of the project is that several of the sinkholes were used as drainage facilities to receive surface water runoff. Read on for a summary of this interesting article. (Photo of sinkhole in Karst Topography being used as a drainage feature, from Duffy (2008b), Civil Engineering Magazine)
This post contains a list of new, revised and otherwise updated ASTM standards that pertain to the geotechnical engineering, materials testing and related fields. Standard C39/C39M for testing the compressive strength of concrete cyllinders was updated, as was C42/42m for obtaining and testing drilled cores and sawed beams of concrete. The month of March also saw several geosynthetic standards being updated or added, including new standards for selecting the test method for geomembrane seams, and for testing the flexural rigidity of geogrids and other geosynthetics. There are also a few updated standards related to asphalt mix design and sampling of asphalt. Click through for updated ASTM Standards relating to geoprofessionals.
Geotextiles are frequently used for subgrade improvement under roadways. Caltrans has released a document titled "Guide for Designing Subgrade Enhancing Geotextiles". This 18-page document covers what situations can be improved using geotextiles and includes a […]