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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 [...]

By kk42|December 13th, 2021|Geotechnical Florida, CPT Blog, CPT Data, Cone Penetration, Geotechnical Arizona, Geotechnical California, Geotechnical Texas, Geotechnical Wisconsin|0 Comments

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 [...]

By kk42|December 10th, 2021|Geotechnical Services, Geotechnical California, Geotechnical Colorado, Geotechnical New York, Geotechnical Texas|0 Comments

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 [...]

By kk42|October 15th, 2021|Geotechnical Idaho, Geotechnical Montana, Geotechnical New York, Geotechnical Oregon, Geotechnical Utah, Geotechnical Wyoming, Geotechnical Kentucky, Geotechnical Arizona, Geotechnical California|0 Comments

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 [...]

By kk42|October 15th, 2021|San Jose, San Francisco, Long Beach, Fresno, Sacramento, Oakland, Santa Ana, Anaheim, Geotechnical California, Los Angeles, San Diego|0 Comments

California agency finds significant liquefaction

Source: State agency finds ‘significant liquefaction’ | Local News Stories | hmbreview.com The green in this map indicates areas on the coast that may be prone to liquefication, according to the California Geological Survey. Illustration courtesy California Geological Survey The California Geological Survey last week released new hazard maps for San Mateo and Contra Costa counties that detailed where landslides and soil liquefaction could likely occur in the event of a significant earthquake. The CGS’s Seismic Hazard Zone maps found “significant” liquefaction zones in parts of San Mateo County, particularly in Half Moon Bay, Miramar and San Bruno. The state has already mapped most of the Peninsula, including Montara Mountain, Woodside and San Mateo. But La Honda and San Gregorio are two notable rural areas that don’t have data accessible yet. Each map, a roughly 60-mile zone called a “quadrangle,” accounts for three types of geologic issues caused by earthquakes: a fault rupture, landslide and liquefaction, which describes the process when seismic tremors cause soil to mix with groundwater and behave like quicksand. The state agency identifies most of the city of Half Moon Bay as inside a liquefaction zone. Its quadrangle is 74 square miles, and the liquefaction zone spans the city’s entire coastline and more, including most of the neighborhoods up to Pilarcitos Creek, including El Granada, Miramar and rural areas like Purisima Creek Redwoods Preserve. The map also identifies fault zones on both the east and west sides of the Half Moon Bay Airport, and more than half of Montara Mountain’s quadrangle is at risk of earthquake-induced landslides. The CGS maps were drafted in February but became official on Sept. 23. Land management agencies and cities use hazard maps to identify properties that require site-specific studies before breaking ground on new development. [...]

By kk42|October 11th, 2021|Long Beach, Fresno, Sacramento, Oakland, Santa Ana, Anaheim, Geotechnical California, Earthquakes, Los Angeles, San Diego, San Jose, San Francisco|0 Comments

Why the Himalayas are crumbling

Source: On a precipice: Why the Himalayas are crumbling The landslides were inevitable, Sunni Ram keeps saying. His village, Thatch, is located right above a highway near Nigulsari village of Kinnaur district, where a massive landslide on August 11 killed 28 people; another 13 were injured. A month ago, another landslide in this district in Himachal Pradesh had killed nine tourists and damaged a bridge. While the incidents have made the headlines due to the high casualties, Ram says, this is not the first time landslides have occurred at these places. “Another landslide near Thatch in 2019 killed three dozen sheep and goats,” he adds. Rockfalls have also become frequent in the last few years. It’s as if the Himalaya is crumbling from these spots, says Ram. A team from the Geological Survey of India, following their visit to Nigulsari, has said in its report that a steeply inclined slope and incessant rainfall are behind the incident. Ram and several other residents of Thatch and Nigulsari, however, blame it on the 1,500 MW Nathpa Jhakri Power Project on the Sutlej. The project has a 27.4 km long headrace tunnel for conveying water to the underground power station. This tunnel, dubbed one of the longest in the world, passes under Nigulsari and Thatch and is not far away from the spot where the landslide occurred. “The effects of the heavy explosions made during the construction of the tunnel in the late 1990s are becoming visible now,” says Govind Moyan, deputy head of Nigulsari gram panchayat. All the five villages under this panchayat, including Nigulsari and Thatch, are affected in some or the other way by the Nathpa Jhakri project. Almost every house has cracks on its walls along with fissures in the fields and gardens. Springs too have dried up, says [...]

By kk42|October 6th, 2021|Geotechnical California, Geotechnical Oregon, Geotechnical Washington|0 Comments

Drone Rules Make Tracking Down Faults a Difficult Feat

Chelsea Scott looks on as Michael Bunds lands a fixed-wing drone in Southern California. Credit: Jui-Chi (Vickie) Lee Source: Drone Rules Make Tracking Down Faults a Difficult Feat - Eos Chelsea Scott and Ramón Arrowsmith, like many earthquake scientists, track down faults. As tectonics researchers at Arizona State University, they need to know where a fault is, how much it’s moved, and how it behaves below the surface. Small uncrewed aerial systems, also known as drones, provide them with high-resolution photographs that capture the necessary information at the scale of centimeters—a higher resolution than some commonly used, easily accessible satellite or airborne data sets. However, collecting drone data along the length of a fault is no simple task. Bigger Is Better A magnitude 7.0 earthquake can produce a 62-mile-long (100-kilometer-long) rupture with surface displacements of up to about 3 feet (1 meter), said Arrowsmith. “You need to have a good enough ruler to measure [that],” he said, which imagery collected from drones can easily provide. The problem, he said, is rapidly covering a 62-mile stretch. Nearly every country that regulates drone operations recommends or requires that pilots maintain visual contact with their drone. One way around the problem is to use a bigger drone. Cheap, heavy quadcopters—helicopters that can easily take off and land—are small compared with lightweight, expensive fixed-wing drones that look like tiny airplanes. In February 2020, Scott and three colleagues spent almost 4 days mapping 25 miles (40 kilometers) of the San Andreas Fault in Southern California. Although they had quadcopters, Scott said “the workhorse was the fixed-wing drone.” “Because fixed-wing drones are so expensive, flight planning is done very, very carefully, and unfortunately the project is over if the drone crashes.” The average quadcopter can be spotted approximately half a mile (0.8 kilometer) away; mapping long linear features like [...]

By kk42|October 6th, 2021|Geotechnical USA, Geotechnical US, Geotechnical Arizona, Geotechnical California, Geotechnical Nevada, Geotechnical Utah, Earthquakes|0 Comments

Peer-Reviewed Paper Explains Unprecedented Performance of BioLargo’s AOS Water Treatment Technology

Source: Peer-Reviewed Paper Explains Unprecedented Performance of BioLargo's AOS Water Treatment Technology - Digital Journal WESTMINSTER, CA / ACCESSWIRE / October 4, 2021 / BioLargo, Inc. (OTCQB:BLGO), a developer of sustainable cleantech technologies and full-service environmental engineering company, announced the publication of an important peer-reviewed article confirming that its innovative water treatment technology, the Advanced Oxidation System (AOS), generates highly energetic iodine molecules. The article establishes the foundational scientific principles about why the AOS is a powerful, efficient, and novel water treatment technology. The BioLargo AOS, which is currently deployed in a demonstration pilot project at a municipal wastewater treatment plant, is a ground-breaking water treatment platform that provides rapid and effective disinfection and concurrent organics removal while consuming less electricity than other common treatment technologies. The AOS has previously been shown in bench-scale and pilot-scale studies to exhibit greater water disinfection and decontamination performance than would be expected in similar water treatment technologies. This spurred BioLargo scientists and academic collaborators to elucidate the exact electrochemical mechanisms of the AOS in this study. The paper, published in the American Chemical Society’s journal ES&T Water, examines the mechanism by which the BioLargo AOS produces such rapid and effective disinfection performance relative to past electrochemical water treatment technologies. The study used the Canadian Light Source particle accelerator to perform advanced measurements of the chemical reactions that occur inside the AOS during operation. This technique revealed that the AOS generates highly oxidized iodine molecules that the researchers concluded are likely responsible for the technology’s elevated disinfection efficacy. These special iodine molecules were only present inside the active layers of the AOS and were neutralized before water flowed out of the AOS. Dr. Richard Smith, President of BioLargo Water commented, “Our AOS technology is a technical leap forward in advanced water treatment. This study is [...]

By kk42|October 5th, 2021|Geotechnical West Virginia, Geotechnical California, Geotechnical New Mexico, Geotechnical Oklahoma, Geotechnical Texas|0 Comments

Why did Morro Bay officials select the site of the water recycling plant?

Source: Why did Morro Bay officials select the site of the water recycling plant? Have you wondered why the Morro Bay City Council in California chose the South Bay Boulevard site for the Water Reclamation Facility? Why this site when it did not provide any public benefit that other sites didn’t offer? The council members knew that it added at least $26,000,000 to the lowest cost option and that it required digging up Quintana Road. And they knew it would mean decades of pumping all of Morro Bay’s raw sewage almost three miles inland and uphill. In 2017, the city council convened a peer review panel of wastewater professionals who informed council members that the best way to reduce project costs was to not use the South Bay Boulevard site. The panel said that “the biggest contributor to cost at the South Bay Boulevard site is the site itself. Pipeline and earthwork costs there are very high.” But why this site when the entire project site is designated by San Luis Obispo County as a Geologic Study Area (GSA)? According to the county’s Estero Area Plan and land use ordinance GSA means that the ground is subject to high landslide risk. The Geologic Hazard Map in the project Environment Impact Report (EIR) also shows that the whole project site is designated a “landslide risk”. The city’s own geotechnical report describes the soil at the project site as including “… landslide deposits …” and as “…commonly associated with … slope instability and landsliding,” And — especially in light of these known hazardous conditions — why this site when it is on the bank of a stream that flows directly within about a mile into the Morro Bay National Estuary? Stormwater carrying soil from a landslide could cause catastrophic harms to the estuary. Then there are the facts that there is [...]

By kk42|October 4th, 2021|Geotechnical California, Los Angeles, San Jose, San Francisco, Fresno|0 Comments