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Researcher Aids Arkansas Highway Projects Through Subsurface Analysis

Source: Researcher Aids Arkansas Highway Projects Through Subsurface Analysis | University of Arkansas FAYETTEVILLE, Ark. – A University of Arkansas geotechnical engineer is collaborating with the Arkansas Department of Transportation to map subsurface conditions before road construction begins to identify issues early and help keep highway construction projects on track and on budget. Clint Wood, a civil engineering associate professor and geotechnical engineer, creates profiles of subsurface conditions and soil composition by sending stress waves into the ground and measuring their response at the surface. The non-invasive technology is similar to how ultrasound imaging works on the human body. The technology provides important information for highway designers and construction contractors, who’ve had to rely on imperfect methods for determining subsurface conditions, such as exploratory drilling, a strategy that can miss changes between limited drilling locations. Wood compares designing based on limited exploratory drilling to navigating with an incomplete map. The research is conducted for and in conjunction with the Arkansas Department of Transportation. With an additional $115,318 grant, the transportation department has provided a total of $561,427 in funding. The work focuses on estimating the depth and stiffness of bedrock for new highway alignments and understanding subsurface conditions that cause slope instability. The latter is especially important for understanding how water moves through a slope. Unexpected changes in bedrock depth near slopes can also create pockets where water collects, which can cause the soil in the slope to become saturated, leading to instability. Projects that encounter these issues can face substantial extra costs and delays while designers and contractors adapt the original plan or have to attempt another repair. Those problems can be avoided, or at least minimized, by better understanding the subsurface conditions through non-invasive testing. LIDAR AND DRONE ACCURACY In a separate project, Wood and several other U of A [...]

Geologists and Geotechnical engineers provide flood risk management

Source: DVIDS - News - Geologists and Geotechnical engineers dig deep to provide flood risk management At the Arcadia flood risk management project, in Arcadia, Wisconsin, geotechnical staff are gathering data using a unique method of subsurface exploration. The Cone Penetrometer Test, or CPT, is one method used to identify and characterize soils. The CPTs were conducted with assistance from the Savannah District geotechnical and geology branch. “We benefited from their expertise and cooperation,” said Greg Wachman, senior geotechnical engineer. In CPTs, a device with a conical tip and metal sleeve measure penetration resistance as it’s pushed into the ground. Those measurements are used to characterize the soils’ engineering properties. For example, the forces on the device as it’s pushed through a soft clay are very different from those as it’s pushed through a dense sand, Wachman said. The device also records pore water pressure, which aids in understanding soil permeability and groundwater characteristics. CPTs vs. soil borings A CPT is most useful when used together with standard soil borings, Wachman explained. A soil boring drills into the ground to retrieve physical samples. In contrast, with a CPT, the soil is never seen. CPTs are significantly faster than standard borings and provide continuous test data with depth. With a soil boring, samples are collected about every 5 feet, or change in material, so it’s possible to miss important information. One limitation of the CPT, due to excessive friction, is that it may not be extended to the same depth as a soil boring. The CPTs at Arcadia are being pushed to approximately 60-70 feet, whereas a soil boring can be performed in excess of 100 feet. “By doing some CPTs next to soil borings – where we know what the soils are – we can increase the likelihood that we [...]

Long-Term Testing Of Concrete Bond Durability

Source: Long-Term Testing Of Concrete Bond Durability   The definition of concrete durability can be explained as the ability of a specimen to resist any form of weathering action, namely abrasion, chemical, physical, or any other process of deterioration. In other words, the durability of concrete can also be defined as the ability to last a long period of time without significant deterioration or failure. Image Credit: Peshkova/Shutterstock.com Types of weathering include mechanical, physical, and chemical weathering of concrete including the alkali-aggregate reaction of sulfate attack and chloride attack. Different long-term testing methods have been used over the years and more research has been done to improve the existing methods to be more economical and environmental. Consideration has also gone into methods that reduce the time in which these tests can be completed and assessed. The Importance Of Long-Term Durability Testing It is important to test for the durability of concrete bonds because of the following reasons. Firstly, concrete testing will allow the designers to determine accurately the lifespan of a specific structure according to its specific needs or requirements. If a structure is intended to last a specific period of time, long-term concrete testing can reveal the combination that is required for it to last that long. There can be economic and environmental benefits to this testing. Economically, constant rehabilitation and patching up of structures are very expensive. Hence, long-term testing can reveal the right combination of concrete mixtures for durable structures, thereby reducing the number of times for rehabilitation. Environmentally, constant rehabilitation will require more use of natural resources such as sources of energy, gypsum, or steel to continuously rehabilitate worn-out structures. Continued rehabilitation increases the carbon footprint, which is not environmentally friendly. Developments In Concrete Bond Materials New studies have revealed that the addition of carbon fibers amounting [...]

Corps honors Flynn for geotech work

Source: Corps honors Flynn for geotech work EDWARDSVILLE — Southern Illinois University Edwardsville School of Engineering (SOE) alumnus Stefan Flynn has been recognized as the 2021 U.S. Army Corps of Engineers (USACE) Early Career Geoprofessional of the Year. “While simply being nominated for this award meant a lot to me, I was humbled to have been selected,” said Flynn. “It was equally exciting to see an award created for early career professionals. This award is a testament to the leadership of the Geotechnical, Geology and Materials Community of Practice and their efforts to support, involve and recognize our employees at all professional levels.” “For those organizations that are not already doing so, I highly encourage you to consider ways to recognize your younger/early career professionals,” said Flynn. “I am both proud and grateful to work for such a dedicated and impactful organization as the USACE with our great teams across the nation, within the Mississippi Valley Division, and at home in the Rock Island District.” In 2014, while pursuing a bachelor’s in civil engineering at SIUE, Flynn began working with the USACE as a student intern at the St. Louis District. Upon graduation in 2015, he was offered a full-time job with the Rock Island District. He currently serves as a senior geotechnical engineer and conducts design, construction and inspection of dams, levees and navigation structures. The Early Career Geoprofessional of the Year award recognizes Flynn for exhibiting professionalism and commitment to excellence through: • Enhanced regional and/or national projects, • Achievements and innovations in geotechnical engineering, geology or materials engineering, • Contributions to professional/technical societies, • Enhanced relationships with peers, partners and contractors, and • Demonstrated exemplary levels of trust and integrity. During his time at SIUE, Flynn served as a research assistant and conducted research for the Illinois [...]

Oil wells in L.A. and Residential Health Problems

Source: Oil wells in L.A.: Nearby residents grapple with health problems Magali Sanchez-Hall, a Wilmington resident for over two decades, has struggled with asthma her entire life. She says the health issue stems from her proximity to oil and gas drilling. Emma Newburger | CNBC LOS ANGELES, CALIF. — Stepping out of a coffee shop near Interstate 110 in the Wilmington neighborhood of Los Angeles, you’re immediately hit by a foul odor. Magali Sanchez-Hall, 51, who’s lived here for more than two decades, is used to the smell of rotting eggs wafting from the hundreds of oil wells operating in the neighborhood. She’s used to her neighbors describing chronic coughs, skin rashes and cancer diagnoses, and to the asthma that affects her own family, who live only 1,500 feet from a refinery. “When people are getting sick with cancer or having asthma, they might think it’s normal or blame genetics,” she said. “We don’t often look at the environment we’re in and think — the chemicals we’re breathing are the cause.” Wilmington, a predominantly working-class and Latino immigrant community of more than 50,000 people, has some of the highest rates of asthma and cancer in the state, according to a report by the non-profit Communities for a Better Environment. It’s surrounded by six oil refineries and wedged in by several freeways and the ports of L.A. and Long Beach. California, the seventh-largest oil-producing state in the U.S., has no rule or standard for the distance that active oil wells need to be from communities. For many Californians, especially Black and brown residents, acrid smells, noise and dirt from oil production is part of the neighborhood. Walking around Wilmington, pumpjacks are visible in public parks, next to schoolyards where children play and outside of people’s windows at home. At night, the sky is lit [...]

Studying the ground under your feet: Interview with Taylor Hall about rock and soil stability

Source: Studying the ground under your feet: Science Moab speaks with Taylor Hall about rock and soil stability | Get Out & Go | moabsunnews.com Moab is renowned for its biological soil crusts, but what’s happening underneath all that crusty black — with the soil and rock itself? This week, we speak with geotechnical engineer Taylor Hall, owner of the Moab Geotechnical Group, about soil mechanics, engineering tools, and how he decided — at age 15, in a McDonald’s — to start working with the dirt. Science Moab: What is geotechnical engineering? Hall: Geotechnical engineering generally deals with rock and soil mechanics and physics: how those materials will respond to structures or just how they respond to gravity. We might look at something like a bridge to understand its foundations, or we might look at a landslide that gets triggered by natural causes. We’re fortunate to be able to come in there and tell you how things are responding and why and what to expect. Science Moab: How do you test soil? Hall: When geotechnical engineering got its feet in the 1940s and 1950s, they would sample soil by drilling a hole and driving a sampler into the ground using a fixed-weight hammer. Using that method, we were able to acquire a sample and get some resistance associated with that sample. That's much of what we do today, but we do it now because it's backed by 60 or 70 years’ worth of empirical relationships. Generally, you're only dealing with one or two such holes, and you have to use them to characterize a whole site. It's tough, but that's why I chose geotechnical engineering: because no two sites are the same. It provides the opportunity to really think on your feet. Science Moab: Once you’ve taken measurements, how do [...]

Can Enzymes Be the Key to Replacing Concrete in the L.A. Basin?

Source: Is L.A. Like a City Built on Jell-O? Can Enzymes Be the Key to Replacing Concrete? Chukwuebuka Nweke May Have the Answers - USC Viterbi | School of Engineering CHUKWUEBUKA NWEKE. Even as a child 8,000 miles away in Nigeria, Chukwuebuka Nweke remembers the 1995 Kobe, Japan earthquake. “It was a massive, devastating event,” Nweke recalled in an interview earlier this year. “That was probably the first earthquake that I got to see (video) footage about.” Now, Nweke, a geotechnical civil engineer, is a new assistant professor in the Sonny Astani Department of Civil and Environmental Engineering. Seismic hazard modeling — how the ground shakes and how that varies from place to place — is one of his key focal areas, with an aim to helping us allocate resources with priority toward the most vulnerable structures. “Some places could have a lot more damage depending on a number of things, including what’s underneath the ground and what kind of buildings are on there,” he said. “That coupled with information like what kind of service the structure provides or the density of the residing population helps determine the risk level.” For example, Nweke said, if an earthquake takes place in the middle of the desert, with a low or null population, even very large shaking wouldn’t be of great concern. However, in the L.A. basin, it’s a different story, Nweke said. “I specialized primarily in seismic site response, where I’m trying to see how much an earthquake is amplified in areas that are softer, like Los Angeles — the entire basin from Westwood to Orange County is very soft compared to the adjacent mountains,” he said. Nweke, whose scientific curiosity initially stemmed from watching various Discovery Channel series on meteors and the impact of dinosaurs, said Los Angeles is of particular interest in [...]

Report: Drilling spills ruined wells and polluted streams in Westmoreland, across Pennsylvania

Source: Report: Drilling spills ruined wells and polluted streams in Westmoreland, across Pennsylvania | TribLIVE.com Edward Mioduski holds a jar of water produced by his Loyalhanna Township well in June 2017, a month after the water became polluted during drilling underneath nearby Loyalhanna Lake. Alice and Edward Mioduski point to where the Mariner East II pipeline cuts across their farm in Loyalhanna Township. It has been more than four years since Edward and Alice Mioduski of Loyalhanna Township have been able to drink water from their well near Loyalhanna Lake. Drilling mud mixed with the mineral bentonite leaked from the hole that Sunoco Pipeline L.P. was boring underneath the lake in May 2017. It bled into the aquifer that their 95-foot-deep well had tapped into for decades. The crystal-clear water turned cloudy gray with little white blobs floating around. “Within a short time, it went to hell,” Alice Mioduski said. Before that, their water was “the nectar of the gods. We never ran out of water.” Now, they have a 1,500-gallon plastic tank in their backyard that provides water for showering and washing clothes — when it doesn’t freeze in the winter — paid for by Sunoco. A filtration system inside the house provides water for drinking and cooking. The damage to streams and water supplies by the leaks and lost fluids during construction of the 307-mile Mariner East II pipeline is outlined in a 64-page indictment handed down last week by a statewide investigating grand jury. Energy Transfer L.P. of Dallas, a successor to Sunoco Pipeline, was slapped with 48 criminal violations of the Clean Streams Law. Fluids that were to return to the surface and be dumped into a drill pit for reuse simply disappeared underground or bubbled up to the surface. The grand jury alleges [...]

US: Magnitude-6.5 earthquake occurs east of Chignik, Alaska

Source: US: Magnitude-6.5 earthquake occurs east of Chignik, Alaska Oct. 11 A magnitude-6.5 earthquake occurred off the eastern coast of Alaska Peninsula at around 01:10 AKDT Oct. 11. The epicenter was about 114 km (70 miles) east of Chignik. The tremor occurred at a depth of about 46 km (28 miles). Moderate shaking was likely felt across northern parts of the Aleutian Islands and much of Kodiak Island. There have been no initial reports of damage or casualties as a result of the earthquake; however, significant damage is unlikely. It could take several hours until authorities can conduct comprehensive damage assessments, especially in remote areas. Aftershocks are likely over the coming days. Authorities have not issued any tsunami advisories. Officials may temporarily shut down transportation infrastructure in the tremor zone to check for damage. Minor disruptions could occur during shutdowns, but service will likely resume quickly if no damage is found. Utility outages are possible, particularly near the earthquake's epicenter.

Stress in Earth’s crust determined without earthquake data

Source: Stress in Earth's crust determined without earthquake data Scientists at Los Alamos National Laboratory have developed a method to determine the orientation of mechanical stress in the earth's crust without relying on data from earthquakes or drilling. This method is less expensive that current approaches, could have broad applicability in geophysics and provide insight into continental regions lacking historical geologic information. "We utilized the nonlinear elastic behavior in rocks and applied a new technique to monitor the orientation of the maximum horizontal compressive stress in rocks in parts of Oklahoma and New Mexico," said Andrew Delorey of Los Alamos. "The orientation of that maximum horizontal compressive stress reveals which fractures in the rock will be active." North-central Oklahoma was selected because induced seismic activity has been ongoing in the region after decades of injected wastewater from oil and gas operations. That seismic activity occurs on faults optimally oriented in the regional stress field. North-central New Mexico was selected to compare the results to a geologic setting straddling a continental rift separating the Colorado Plateau from a stable section of the earth's crust. The scientists determined that the earth exhibits stress-induced anisotropy of nonlinear susceptibility that is aligned with the maximum horizontal compressive stress in these two different geologic settings. Rocks become stiffer when compressed and softer when extended, but this effect isn't instantaneous. The rate is faster in the orientation where the ambient stress field is most compressive. By measuring this rate in different orientations, scientists can determine the orientation where ambient stress is most compressive. Determining the geophysical stress orientation, or the direction of maximum horizontal compressive stress, is usually determined by drilling narrow, deep boreholes. However, borehole drilling is expensive and only provides a single data point. Additionally for vast regions, the geophysical data simply hasn't been collected because [...]

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