Microbial material modification helps to control frost heave and saline soil solidification

Source: Microbial material modification helps to control frost heave and saline soil solidification Chinese researchers recently conducted a study on process of biogas generation improving physical and mechanical properties of soil. A research team led by Sheng Yu from the Northwest Institute of Eco-Environmental Resources (NIEER) of the Chinese Academy of Sciences (CAS), together with their colleagues from Southeast University, has implanted Pseudomonas Stutzeri in the soil pores and induced it to produce nitrogen bubbles, and they also analyzed the influence mechanism of mitigation of sand liquefaction using biogas bubbles. In the natural environment, there are many microorganisms in rock and soil masses, and its metabolic activities will change physical and mechanical properties of rock and soil. These microbial activities can be controlled, enhanced and used to solve geotechnical problems, and such methods have been named as biogeotechnologies. As an emerging interdisciplinary field, it has developed rapidly in recent years due to its advantages of low carbon and friendly environment. From the perspective of practical application, biogeotechnologies can be used for rock and soil reinforcement, sealing of water leakage, prevention of sand liquefaction, soil erosion resistance control, and contaminated soil treatment and so on. Based on the above research results, the NIEER research group is exploring to apply biogeotechnologies to frost heave control and saline soil solidification, and has achieved some preliminary results. In this study, the researchers applied biogas generation process to soil frost heaving treatment, and studied improvement of biogas production performance under low temperature conditions. Results showed that sealing effect of bubbles and microorganisms on the water migration path can reduce soil permeability coefficient by one order of magnitude. Besides, they also introduced biomineralization to solve the prominent problem of saline soil with high chloride content in Northwestern China. Based on excellent curing effect, they analyzed the deterioration mechanism of [...]

Mitigating carbon may have unintended consequences

Source: Mitigating carbon may have unintended consequences | Penn State University UNIVERSITY PARK, Pa. — Controlling carbon release into the atmosphere will reduce carbon dioxide and slow global warming, but could there be unintended consequences for human health? Now, thanks to a three-year grant of about $400,000 from the National Science Foundation, researchers at Penn State will investigate potential positives and negatives of decarbonization. "There can be unintended health co-harms from some carbon mitigation strategies," said Wei Peng, assistant professor of international affairs and civil and environmental engineering and principal investigator on the project. "For instance, large-scale bioenergy production may drive up food prices, which leads to nutrition-related health co-harms." Of course, mitigating carbon can also bring health benefits, including a reduction of pollution in the atmosphere. "Tangible human health co-benefits can motivate stronger support for climate policy," said Peng. The researchers aim to improve understanding of what factors determine the size and scope of health outcomes from decarbonization and to identify strategies most likely to yield overall health benefits. Focusing on the U.S., Peng and her team will develop a framework integrating energy, food and health. They will improve health variables in a state-level integrated assessment model and connect it to a fine-resolution, health impact assessment model. They will also develop a large number of scenarios of decarbonization to encompass future uncertainties, technology and markets. This project is the extension of two seed grants from Penn State's Institutes of Energy and the Environment and Institute for Computational and Data Sciences. Vivek Srikrishnan, assistant professor of biological and environmental engineering, Cornell University, is the co-principal investigator (PI) on this project. Peng is also a co-PI on a project looking to model the interactions of climate change, air quality and social inequalities. This five-year, $1.5 million NSF grant, co-led by Mark [...]

Breaking Uncommon Ground in the Kansas Countryside

Source: Breaking Uncommon Ground in the Kansas Countryside - Alpha-Omega Geotech, Inc. Look beyond I-435 to the west of Kansas City’s urban core and you’ll see a surge of new commercial development taking shape. It’s not all typical, flat farmland and turning it into opportunity requires a strategic approach. Before you put together plans for a construction project, consider a few pointers based on our experience. Don’t Be Surprised by a Predictably Unpredictable Subgrade. Be careful not to make assumptions about what’s just below the surface and deeper down, especially along K-10 in the vicinity of Lenexa. Every potential build site is different to some degree and variations from site to site can be substantial. Much of the landscape is hilly, and history has left behind miscellaneous man made factors that will impact everything from site selection to construction. Decades of variables ranging from undocumented subgrade material, buried trees and buried gravel roads to improperly filled farm ponds lurk underground, even in areas that appear to be untouched. In addition, old limestone mines abandoned as far back as the 1980s wind through the area and present ongoing challenges for developers. The proximity of mines isn’t necessarily a deal breaker when it comes to project site selection, but you’ll need to clearly understand the limitations of the subgrade above and around them. You’ll also need to be on the lookout for mine spoils material carved out over the years and buried for disposal. Uncovering subgrade wildcards and narrowing site selection is only possible through an extensive investigation. A precise boring plan with thorough soil testing will be critical in the hunt for a project site that’s feasible in context of your timeline and budget. Make sure your geotechnical engineering partner knows exactly how you expect foundations to perform so that they can pinpoint [...]

WIU Graduates First Civil Engineering and Electrical Engineering Students

Source: WIU Graduates First Civil Engineering and Electrical Engineering Students Associate Professor of Engineering Blair McDonald and Jeremy May, new alumnus of WIU Civil Engineering MACOMB, IL - - The Civil Engineering and Electrical Engineering programs on Western Illinois University's Quad Cities campus have marked their first graduates. Jeremy May, of Geneseo, IL, received his degree in Civil Engineering, and Dakota Wilson, of East Moline, IL; Jeffrey Latham, of Davenport IA; and Travis Ohlsen, of Moline IL received their degrees in Electrical Engineering in May. In Spring 2019, the Illinois Board of Higher Education (IBHE) approved new degrees in Electrical Engineering (EE) and Civil Engineering (CE) within the WIU School of Engineering, which began in Fall 2020. Western's Civil Engineering program prepares graduates to work in the structural, geotechnical, transportation and water resources areas of either government (local or federal) or private practice. While May is the first Civil Engineering graduate from this new program, several students have graduated in recent years with a civil engineering emphasis, and all are now working with companies such as Shive-Hattery, Inc., Bruner, Cooper & Zuck, Inc., the US Army Corps of Engineers and Illinois Department of Transportation. Many WIU Engineering graduates have gone on to obtain their professional licensures, which involves a four-year process following graduation. Electrical Engineering develops students' knowledge of rapidly expanding technologies in electricity, electronics and electromagnetism. One of the requirements of an EE degree is to take an additional math course, Linear Algebra, which allows all EE students to automatically obtain a minor in Mathematics. Latham, Ohlsen and Wilson all make up the EE Senior Design Team for an Autonomous Tracked Vehicle. Latham plans to continue his education with the University of Arizona's Engineering-Robotics and Automation graduate program. Ohlsen recently completed his internship with KONE Escalator Supply Unit and began working full [...]

UD researchers study climate change impacts on soils at military installations

Source: The Ground Underfoot - Civil and Environmental Engineering UD researchers study climate change impacts on soils at military installations We walk over it, drive over it and build on it. Yet, it is probably safe to say, most of us rarely think about the ground beneath our feet. Underneath the grass, concrete, asphalt and other materials in our built environment, however, soil provides structure and stability for what lies above. The United States military wants to understand the role that climate impacts, such as flooding, storm surge or sea level rise, will have on soils at its coastal military bases and facilities, which are critical to national security. Soil conditions can affect the integrity of the ground underpinning buildings, roads, bridges and more. For example, if a soil’s pH were to rise significantly, due to increased salt content-containing ions such as sodium from storm surge, it could create saline conditions that could hamper the ground’s ability to support this necessary infrastructure. Understanding these threats will enable faster and more accurate routing and maneuverability for U.S. forces. The Delaware Environmental Institute (DENIN) is collaborating with the Engineer Research and Development Center (ERDC) of the U.S. Army Corps of Engineers and Louisiana State University to understand how vulnerable military installations along coasts may be affected by soil changes due to sea level rise and coastal flooding. DENIN has received $3.79 million in first- and second-year funding from the U.S. Department of Defense to start this work, and is eligible for an additional $3.82 million in continued funding over the following two years. Led by DENIN Director Don Sparks, Unidel S. Hallock du Pont Chair of Soil and Environmental Chemistry in UD’s Department of Plant and Soil Sciences, the UD effort includes interdisciplinary collaboration with Yan Jin, Edward F. and Elizabeth Goodman Rosenberg Professor [...]

Parameters Variation Model Customization and Sensitivity Analyses

Source: Parameters Variation: Model Customization and Sensitivity Analyses Parameters Variation Model Customization and Sensitivity Analyses A well-known engineering challenge in the framework of finite element (FE) analysis-based design is the large number of input factors involved in geotechnical computational models. There is always a significant amount of uncertainties associated with the properties of geomaterials, being naturally highly heterogeneous materials. In the context of model calibration and validation, conducting a sensitivity analysis is very important. This can determine the key factors which govern the system and efficiently characterize the geotechnical variability for any considered design problem.   Powerful mechanisms for the consideration of parameter variation are also very interesting for speeding up FE model creation and automating results in post-processing. These are also quite useful in reducing model definition for specific types of engineering problems (excavation wall of a specific type under simple ground conditions, simple tunnel shape in uniform rock mass, etc.) to a limited number of parameters that can be inputted in a text file or Microsoft Excel spreadsheet without expert knowledge of the PLAXIS user interface and different modeling techniques and FE know-how. The sensitivity analysis and parameter variation tool in PLAXIS A sensitivity analysis determines how different values of an independent variable affect a particular dependent variable under a given set of assumptions. In other words, sensitivity analyses study how various sources of uncertainty in a mathematical model contribute to the model's overall uncertainty. The Sensitivity Analysis and Parameter Variation tool (see Figure 1) can be used to evaluate the influence of model parameters on calculation results for any particular PLAXIS FE model: The Select Parameters tab sheet will first provide information about all the parameters that can be changed to perform the sensitivity analysis. Available parameters include most model parameters of the data sets for soil and [...]

A Climate Change-Induced Disaster in Denali National Park

Source: A Climate Change-Induced Disaster in Denali National Park | Time The Times has recently showcased an article on the current rockslide situation in Denali National Park. The effects of climate change have been dramatic with the current melting of the permafrost. The National Parks Service has recently upped through gravel removal of the Pretty Rocks Landslide in an effort to keep up as the rapidly thawing permafrost picks up pace. Alaska is right now recognized as the country’s fastest-warming state. The landslide hit unprecedented speed 4 weeks ago causing the team to close the back half of the park weeks earlier than anticipated. This only signals bad news as reservations are canceled in the short term and the long term implications are yet unknown. “This is the canary in the coal mine for infrastructure disruption in Alaska,” says the Camp Denali lodge owner Simon Hamm. “If things continue on the path they’re on, it’s not going to just be Pretty Rock—it’s going to be half of the Alaskan highway system.” Rapid deterioration Denali National Park is one of the U.S.’s largest national parks at 6 million acres, and sits about four hours north of Anchorage. While the entrance to the park is certainly beautiful, many people prefer to hop on buses to access the park’s marquee attractions deep down its single 92-mile road: views of Mt. Denali (formerly Mt. McKinley), the highest peak in North America at 20,000 feet; the gleaming Wonder Lake; rolling mountainsides that contain an abundance of wildlife, including grizzly bears, moose, caribou and bighorn sheep. About halfway along the road lies the Pretty Rocks Landslide, a slowly sliding section of earth that acts more like a glacier than a rockfall. Since the 1960s, permafrost deep below the earth’s surface has thawed, causing the soil and [...]

Screening for Soil Contamination Levels with CPT

Expanding from geotechnical Cone Penetration Test (CPT) into other services is a great way to grow your business. Evaluating subsurface soil contamination provides many business opportunities and a way to differentiate yourself from other CPT service providers – allowing you to protect your business, while expanding into new regions and adding clients. In many instances, the existence of environmental contaminations in an area is known, but the question that needs to be answered is, “where is it”? In other posts, we explain how CPT works, and how it can be used to characterize the strata underground hundreds of feet deep, depending upon the actual subsurface conditions, the equipment being used etc., In addition to identifying soil types by layer and depth, geo-technical CPT testing also helps to establish groundwater levels and potential migration pathways. This makes it useful for identifying where contamination may migrate or be confined. Establishing a depth profile of the contamination underground and how the ‘plume’ is located and migrated, or where it is likely to expand in the future is vital to establishing a cleanup or remediation plan. Once contamination has been shown to be likely, our discrete soil and ground water sampling equipment delivers physical samples for confirmation. Once CPT became well-established and proven as a geo-technical evaluation tool, it was natural to try and see what other types of testing could be accomplished using the same tools. In addition to mapping groundwater conditions with in-situ pore pressure transducers, CPT tools that sense the direct presence of various types of hydrocarbons and other volatile organic compounds at depth are now available. A variety of cone sensors can be used to test for specific types of contamination. Multiple CPT equipment modules can be configured with multiple sensors, including soil moisture resistivity, video, radiation and sensing for [...]

Hollow Stem Augers Don’t Provide the Accuracy that CPT has to Offer

Geo-technical Boring is less accurate, less efficient and more expensive than Cone Penetration Testing (CPT), here's why. When it comes to selecting a method for subsurface investigation and testing you are presented with different options. From the Standard Penetration Test (SPT), which is a type of Geo-technical Soil Boring to Cone Penetration Testing (CPT) there are many options to consider, and each provides certain advantages over the other. Today we’re going to compare Geo-technical Boring to CPT. Geo-technical boring is a method of drilling which is performed for site investigation. This drilling technique is most commonly used to obtain information on the physical properties of soil and rock under a foundation. This information helps to determine the depth of the foundation, ensure the site is safe and determines if structural compensations will be needed. This also ensures that the foundation, caissons and various supports are built in the right place. Hollow Stem Augers One type of geo-technical boring using a hollow stem auger is the Standard Penetration Test. Like it's name suggests, a hollow stem auger is a drilling tool that enables you to capture soil samples in the hollow portion of the drill for retrieving to the surface. One advantage of this approach is that you have actual soil samples you are working with. In the case of identifying the presence, location and depth of specific types of contaminants, this can be useful. Cone Penetration Testing Though geo-technical boring seems like a sufficient option for site subsurface investigation, geo-technical boring doesn’t provide the accuracy and efficiency that Cone Penetration Testing (CPT) can offer. Geo-technical Boring has the advantage that it uses many of the skills of conventional well drilling. Because the Boring operations and technical analysis, such as laboratory tests, are separate, Geo-technical Boring can require less skilled operators [...]

Why Are There So Many Kinds of CPT Rigs?

As you look through our website, you'll see that there are a number of different types of CPT Rigs. As you can imagine, they each have their purpose, or 'application'. In order to understand why different types of CPT Rigs exist, it's helpful to remember how CPT works in the first place. Cone Penetration Testing The goal of Cone Penetration Testing is to drive a hardened cone vertically into the the ground and to keep it moving at a specific rate of progress. The force that it takes to maintain the cone moving downward at a defined rate is an indicator of how hard the soil is at a given depth. The friction the cone sleeve encounters along the way gives us an indication of the make up of the soil. Deciding Between CPT Rigs As you can imagine, as the cone progresses further downward and encounters different types of soils, sands, clays and rocks it can take a substantial amount of pressure to keep it moving! One of the first factors that influences the design of CPT Rigs is the maximum amount of pressure that will be required to perform a specific test, to a specific depth in a given geological area. As much as 20 tons of downward force may be required to perform a broad enough range of tests to make a given rig viable for a market. For every ton of downward pressure on the test cone through the rod system, you have to have a reaction force equal to this to keep the Rig from lifting up. This means that either the Rig has to be heavier than the maximum push force, plus a safety margin, or it needs to be anchored down in some way as to reliably resist the upward force generated by [...]

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