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 flowchart for guidance on when to apply them and for what purposes. From Geosynthetics magazine. (Image by Caltrans)
Devil’s Slide is an infamous landslide along California’s Highway 1 or Pacific Coast Highway near Pacifica, just south of the San Francisco Bay area. Caltrans’ Devil’s Slide Tunnel project is an effort to bypass that slide and make the heavily traveled roadway safe for drivers and to eliminate the maintenance and traffic hassles caused by slope failures blocking the road. We first covered the project back in September of 2007 when the tunnel portion of the project commenced. In that post, you can find a Google Earth KML File showing the location of the tunnels and the new bridges associated with the project. In this post, Iâ€™ll provide you with some updated progress information as well as some background on the geotechnical and other aspects of the project. More links and videos are at the end of the post. (Photo by Kim Komenich, San Francisco Chronicle). […]
Another busy month for ASTM with 66 new, revised or otherwise updated standards related to geotechnical and geological engineering (although not as busy as last month). A couple that caught my eye include brand new standards for geospatial data requirements related to abandoned mines, a new standard for sampling of EPS or geofoam, updated standards for mortar and cement, flexural strength of concrete, LA Abrasion test for aggregates, acceptance testing of geosynthetic clay liners, electrical methods for leak detection of geomembranes with earth cover and classification of soils and soil-aggregate mixtures for highway construction purpose (AASHTO classification).
Those involved in the materials testing side of the business should take a close look at the full list as there are also a number of updated standards relating to various asphalt and and aggregate tests, capping of concrete cyllinders and other related testing standards.
For my practice, perhaps the most significant standard that was updated was D 2488 – Standard Practice for Description and Identification of Soils (Visual-Manual Procedure) which we rely on for our field USCS classifications. I’ll be curious to see what those changes entail. Click through for the full list.
The Geosynthetic Institute has released a white paper examining ‘U.S. State Environmental Agency Status with Respect To Reviewing and Permitting Mechanically Stabilized Earth (MSE) Landfill Berms’. The use of MSE Walls to buttress landfill berms […]