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US Wick Drain of Leland North Carolina recently completed the world's largest marine barge wick drain installation...over 12 MILLION linear feet. The wick drains will allow timely consolidation of marine sediments supporting dikes for the new Craney Island Port in Norfolk, Virginia. The equipment was installed with APE wick drain installation machines through steel pipe-lined holes in the barge. Engineers predict 21 feet of settlement once the wick drains are preloaded. [Source: APE News via National Driller. Image: APE News (Backus Aerial Photography)]
I kept the same title of the source article for my post...it is a very simple explanation of the enhanced geothermal systems or EGS process of extracting geothermal energy from hot, dry rocks...even if it is a little sensationalized. The AP article describes the well-funded Newberry Crater Geothermal project in Central Oregon. The project is being run by AltaRock Energy, Inc. of Seattle and Davenport Newberry Holdings LLC of Stamford, Conn. with $43 million in funding from the US Federal Government, Google and other investors.
The site is an inactive volcano that has not erupted since before the last ice age. There is plenty of heat available, but unlike conventional geothermal projects, there is no water in the formation and/or the rock is too impermeable for the fluid to flow. Enter the EGS technology, which involves something they are calling hydroshearing, where water is injected into the hot boreholes along with some kind of polymer particles (not sure of the size). The cold water contacting the hot rock causes fractures to form, and the polymer particles keep the cracks open allowing water to flow deeper into the formation and form additional cracks. Eventually the polymer melts away. This process is similar to the hydrofracking I've posted about recently, but the oil and gas industry uses sand to wedge the fractures open and there was no mention of chemicals in the EGS process.
One major concern with EGS and most geotehrmal projects is the possibility of induced seismicity, or man-made earthquakes, something that has been in the news a great deal recently. The testing will involve injecting water at a rate of 800 gallons per minute into a borehole 10,600 feet deep. The projected fractured area is from 6,000 to 11,000 feet below the ground surface in a radius of approximately 1,700 feet around the borehole. The extent of the fracturing and presumably the magnitude of any seismic activity will be monitored using a network of seismic sensors. [Source: Yahoo! Green (AP) via ASCE SmartBrief. Image: Newberry Geothermal]
The landmark City of Venice, Italy is known for it's world famous canals, architecture and for some...its flooding. Part of the problem has been blamed on ground subsidence from pumping of shallow ground water in the mid 1900's. A massive project dubbed MOSE has been in progress for some time to build inflatable gates to stop high tides from flooding the Venice lagoon.
A recent paper in the Journal Water Resources Research evaluates the possibility of injecting water into the formations to stop and perhaps even reverse the subsidence. The article from Ars Technica (link below) mentions that the technique was used with some success in the Long Beach, California area. The study authors had no boreholes in the area, but were able to rely on a large volume of high-quality seismic data obtained by the Italian Government from oil companies. Their simulations involved 15 boreholes around the City of Venice pumping seawater continuously for 10 years. At that point, they authors concluded there is the potential to lift the city 25-30 cm. [Source: Ars technica via Geoengineer.org. Image: De Saye / Rapho via arlindo-correia.com]
Crux Subsurface, Inc. of Spokane, WA was recently awarded a contract by San Diego Gas and Electric to provide design and installation of micropile foundations at 16 tower locations along a 7 mile stretch of power line for a wood to steel replacement project. Crux is best known for their difficult access and extreme access geotechnical construction and geotechnical investigation work, including helicopter access in rugged terrain which seems to be the case on this project. The work is scheduled to begin this month. [Source: National Driller. Image: National Driller]
Foamed concrete has been used in geotechnical applications as lightweight backfill material in applications where reduction of vertical or lateral loads was critical. In this application, the foamed concrete is designed to 'fail' when an aircraft overruns the regular runway. The foamed concrete Engineered Materials Arresting System or EMAS stops the aircraft without causing catastrophic damage. According to the article, there are about 30 runway overrun accidents each year involving commercial aircraft, and there have been about 1,000 deaths from these types of accidents since 1995. [Source: Gizmodo via ASCE SmartBrief. Image: Gizmodo]
In this 2007 ENR article, a drilling superindtendent from Case Foundation, Rob Jones, is profiled while his company works on the foundations for a Chicago highrise. As a geotechnical engineer who designs drilled shaft foundations, I found it very interesting to learn more about the guys on the construction end of drilled shafts. There is no question in my mind that those guys work a lot harder than I do. [Source: ACE Mentor Program. Image: ENR]
A steel sheet pile cofferdam has been built around the HMS Alliance, a British submarine launched in 1945. The cofferdam will be infilled to create a safe place to perform restoration work. [Source: New Civil Engineer. Image: NCE]
December 8th 2011 5:00 PM - American Piledriving Equipment's 8-hammer “Octakong” vibratory pile driver hammer drove the final record breaking pile in front of a crowd of over 200 people on the South China Sea, who came to witness the world's largest pile drive to grade. The last of 120, 72’ diameter steel piles has been driven into place, completing construction of two circular sea bound walls in the South China Sea, for the Hong Kong-Zhuhai-Macau Seaway project.
[Editor] Click through for the rest of the press release and an installation video. [/Editor]
Scott Deaton is the President of GeoPrac sponsor Dataforensics that specializes in data collection for geotechnical engineering, materials testing and environmental engineering. This video was created by Terracon as part of their Green Light series on "What's Driving Innovation in Transportation".
Young geotechnical engineers and geoengineering professionals in the first 5 years of their careers may be elligible for a $500 grant to attend the 2012 Geo-Congress conference in Oakland, California March 25-29. See the Geo-Institute link below for more information. Applications are due by February 25, 2012. [Source: Geo-Institute]
