Carbon sequestration is a hot topic these days, and the Arizona Geologic Survey (AZGS) is working with a consortium of public and private agencies and non-profits to evaluate the potential of CO2 storage in Cenozoic basins in Arizona. The report is still very preliminary, but a number of deep sedimentary basins have been targeted for further investigation, including basins containing most of Arizona’s population centers like Tucson, Phoenix Metro, Casa Grande and Yuma. [Source: Arizona Geology via Arizona Geology Blog. Image: AZGS]
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Arizona Geologic Survey Releases Earth Fissure Maps
Yesterday the Arizona Geologic Survey (AZGS) released the first two of their 1:12,000 series earth fissure maps to the general public. The mapping program, perhaps the first of its kind in the country, came about after an earth fissures opened up in 2005 near Queen Creek, AZ, southeast of metropolitan Phoenix received much media attention. As a result, the Arizona Legislature passed House Bill 2639 of the 2006 Legislative Session that tasked the AZGS with mapping earth fissures and providing the data to the State Land Department for eventual delivery to property owners in Arizona. More after the break. (At left, the Apache Junction study area map, AZGS)
Changes in Geotechnical Engineering Practice in Arizona
[Editor] Note: NCS Consultants, LLC is Randy Post’s full time employer…ie. my day job! [/Editor]
There are some significant changes being made to the state of the practice in geotechnical engineering in Arizona. NCS Consultants, LLC has prepared three policy memoranda for the Arizona Department of Transportation or ADOT that have been issued to consultants all over the State. These memos are on the topics of bearing capacity and settlement of spread footings and retaining walls, the design of drilled shaft foundations in gravelly soils, and the preparation of drilled shaft axial capacity charts for use by bridge engineers.
Although primarily applicable to upcoming ADOT projects implementing the AASHTO 2007 LRFD code, the memos will have a ripple effect down through other local agencies within the state who frequently defer to ADOT guidelines for geotechnical engineering. Also, the memos and the ADOT/NCS approach to LRFD implementation in geotechnical engineering were presented by NCS at the 2008 TRB Conference in Washington D.C., and many other state DOTs and the FHWA were very excited about the memos. The approach used if not the exact content may become a model for other agencies. More info and links to download the policy memoranda are provided after the break.
Landslide on Arizona SR 87 Closes Highway
On March 21, 2008 a landslide caused the closure of Arizona State Route 87 between Payson and Phoenix near mile post 224. So far there are no official estimates as to the size, but based on aerial photos, it appears to be at least 50,000 sq-ft in plan. The offset at the head scarps was approximately 2-meters (6.6-ft) according to AZGS Geologists on site. It appears to have been a rotational slide as the toe of the landslide heaved the southbound roadway up by as much as 1-meter (3.3 ft). There was an existing soil-nail retaining wall on the slope that was destroyed by the slide as well. Lateral deformations can be seen in photos of the median barrier and the roadway striping. The deformations extended into the northbound lanes as well. More photos and links after the break. (Photo by ADOT)