Geotechnical Maine Archives - GEOTILL provides geotechnical, construction testing and Environmental services Indianapolis Indiana

How the Concrete Vibrator Changed Concrete Mix Design

Source: How the Concrete Vibrator Changed Concrete Mix Design | For Construction Pros Over the last 60 years, concrete vibrators have evolved into a necessary machine for concrete jobs. Industry studies have highlighted separation issues, vibration energy, surface defects, and mix incompatibilities—leading to the development of a more predictive concrete placement experience. Concrete vibration dates to the late 1960s when Thomas Reading, an engineer from the U.S. Army Corps of Engineers, set vibration placement recommendations through vibration tests. At the time, the normal slump of structural concrete was three to four inches, had a “peanut butter” like consistency, and placed in forms by a concrete bucket. Reading used a larger horsepower motor to maintain a maximum vibrator speed that ran the vibrator heads for the current consistency of mixes. Reading concluded that the vibrator frequency should never exceed 10,000 vibrations per minute (vpm) due to his observation of concrete material separation. At that time, the American Concrete Institute (ACI) 309 Consolidation Guidance Specification reflected Reading’s research and limited the vibrator frequency to that maximum frequency. Surface voids were mistaken for entrapped air. Through today’s research, we’ve come to understand that surface blemishes come from vibration-frequency-forced bleed water. Ten years later, mix designs were being transformed by a chemical additive called a water-reducing agent (WRA) to allow for a more workable concrete mix for the future of economical concrete placements by pumping instead of concrete buckets. By the end of the next several decades, the volume of pumped commercial concrete reached 80%. The increased use and type of WRAs (plasticizers) allows for more possibilities of bleeding. With the increased bleeding in pumpable mixes, present concrete mix designs started to take on a "soup-like" consistency. While the vibrator design remained the same, manufacturers began to increase the amount of vibrator frequency. As [...]

By kk42|October 11th, 2021|Geotechnical North Dakota, Geotechnical Maryland, Geotechnical Wisconsin, Geotechnical Louisiana, Geotechnical Maine|0 Comments

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 [...]

By kk42|September 22nd, 2021|Geotechnical Mississippi, Geotechnical Wyoming, Geotechnical Idaho, Geotechnical Georgia, Geotechnical Oklahoma, Geotechnical Nebraska, Geotechnical Louisiana, Geotechnical Maryland, Geotechnical Oregon, Geotechnical North Carolina, Geotechnical Maine, Geotechnical Pennsylvania, Geotechnical Rhode Island, Geotechnical West Virginia, Geotechnical Indiana, Geotechnical Massachusetts, Geotechnical Wisconsin, Geotechnical South Carolina, Geotechnical USA, Soil Testing, Geotechnical Montana, Geotechnical Minnesota, Geotechnical South Dakota, Geotechnical US, Geotechnical Kentucky, Geotechnical Nevada, Geotechnical Alabama, Geotechnical Texas, Geotechnical Arizona, Geotechnical Tennessee, Geotechnical New Hampshire, Geotechnical Connecticut, Geotechnical Utah, Geotechnical Arkansas, Geotechnical Ohio, Geotechnical New Jersey, Geotechnical Florida, Geotechnical Vermont, Geotechnical California, Geotechnical Illinois, Geotechnical New Mexico, Geotechnical Iowa, Geotechnical Virginia, Geotechnical Colorado, Geotechnical Michigan, Geotechnical New York, Geotechnical Kansas, Geotechnical Washington, Geotechnical Delaware, Geotechnical Missouri, Geotechnical North Dakota|0 Comments

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 [...]

By kk42|September 21st, 2021|Geotechnical Missouri, Geotechnical North Dakota, Geotechnical Mississippi, Geotechnical Wyoming, Geotechnical Idaho, Geotechnical Georgia, Geotechnical Oklahoma, Geotechnical Nebraska, Geotechnical Louisiana, Geotechnical Maryland, Geotechnical Oregon, Geotechnical North Carolina, Geotechnical Maine, Geotechnical Pennsylvania, Geotechnical Rhode Island, Geotechnical West Virginia, Geotechnical Indiana, Geotechnical Massachusetts, Geotechnical Wisconsin, Geotechnical South Carolina, Geotechnical USA, Geotechnical Kentucky, Geotechnical Montana, Geotechnical Minnesota, Geotechnical South Dakota, Geotechnical US, Geotechnical Tennessee, Geotechnical Nevada, Geotechnical Alabama, Geotechnical Texas, Geotechnical Arizona, Geotechnical Ohio, Geotechnical New Hampshire, Geotechnical Connecticut, Geotechnical Utah, Geotechnical Arkansas, Geotechnical Illinois, Geotechnical New Jersey, Geotechnical Florida, Geotechnical Vermont, Geotechnical California, Geotechnical New Mexico, Geotechnical Iowa, Geotechnical Virginia, Geotechnical Colorado, Geotechnical Michigan, Geotechnical New York, Geotechnical Kansas, Geotechnical Washington, Geotechnical Delaware|Comments Off

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 [...]

By kk42|September 21st, 2021|Geotechnical Georgia, Geotechnical Oregon, Geotechnical North Carolina, Geotechnical Maine, Tanaina, Geotechnical Maryland, Geotechnical Rhode Island, Geotechnical West Virginia, Geotechnical Massachusetts, Lakes, Geotechnical Pennsylvania, Geotechnical South Carolina, Geotechnical USA, Landslides, Geotechnical Montana, Kalifornsky, Geotechnical Minnesota, Geotechnical South Dakota, Geotechnical US, Geotechnical Alaska, Geotechnical Indiana, Geotechnical Nevada, Geotechnical Alabama, Geotechnical Texas, Geotechnical Arizona, Anchorage, Geotechnical Kentucky, Geotechnical New Hampshire, Geotechnical Connecticut, Geotechnical Utah, Geotechnical Arkansas, Juneau, Geotechnical Tennessee, Geotechnical New Jersey, Geotechnical Florida, Geotechnical Vermont, Geotechnical California, Fairbanks, Geotechnical Ohio, Geotechnical New Mexico, Geotechnical Iowa, Geotechnical Virginia, Geotechnical Colorado, Badger, Geotechnical Illinois, Geotechnical New York, Geotechnical Kansas, Geotechnical Washington, Geotechnical Delaware, Knik-Fairview, Geotechnical Michigan, Geotechnical North Dakota, Geotechnical Mississippi, Geotechnical Idaho, College, Geotechnical Missouri, Geotechnical Oklahoma, Geotechnical Nebraska, Geotechnical Louisiana, Wasilla|0 Comments

Geotechnical Instrumentation and Monitoring Consumption Market Size to Witness Huge Growth by 2027 | By Top Leading Vendors – Keller, Fugro, Nova Metrix, Geokon, Geocomp, Sisgeo, Cowi – The Daily Chronicle

Source: Geotechnical Instrumentation and Monitoring Consumption Market Size to Witness Huge Growth by 2027 | By Top Leading Vendors – Keller, Fugro, Nova Metrix, Geokon, Geocomp, Sisgeo, Cowi – The Daily Chronicle

By smadi66|September 22nd, 2020|Geotechnical Colorado, Geotechnical Tennessee, Geotechnical New York, Geotechnical Connecticut, Geotechnical Washington, Geotechnical Delaware, Geotechnical Illinois, Geotechnical North Dakota, Geotechnical Florida, Geotechnical Wyoming, Geotechnical Idaho, Geotechnical Michigan, Geotechnical Oklahoma, Geotechnical Mississippi, Geotechnical Louisiana, Geotechnical Missouri, Geotechnical Oregon, Geotechnical Nebraska, Geotechnical Maine, Arlington Heights, Geotechnical Rhode Island, Geotechnical North Carolina, Geotechnical Massachusetts, Geotechnical Georgia, Geotechnical South Carolina, Geotechnical West Virginia, Geotechnical Montana, Geotechnical Maryland, Geotechnical South Dakota, Geotechnical Services, Geotechnical Nevada, Geotechnical Pennsylvania, Geotechnical Texas, Geotechnical Arizona, Geotechnical New Hampshire, Geotechnical Wisconsin, Geotechnical Utah, Geotechnical Arkansas, Geotechnical Indiana, Geotechnical New Jersey, Geotechnical Minnesota, Geotechnical Vermont, Geotechnical California, Geotechnical Kentucky, Geotechnical New Mexico, Geotechnical Alabama, Geotechnical Virginia|0 Comments

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 [...]

By smadi66|December 5th, 2019|Geotechnical Illinois, Geotechnical Michigan, Geotechnical Maryland, Geotechnical Iowa, Geotechnical Kansas, Experienced, Geotechnical Louisiana, Geotechnical Maine, Geotechnical Massachusetts, Geotechnical Indiana, Geotechnical Kentucky|0 Comments

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 [...]

By smadi66|December 5th, 2019|Geotechnical Minnesota, Geotechnical Iowa, Geotechnical Kansas, Geotechnical Mississippi, Introductory, Geotechnical Louisiana, Geotechnical Maine, Geotechnical Massachusetts, Geotechnical Kentucky, Geotechnical Michigan, Geotechnical Maryland|0 Comments

The Importance of Proper Soil Quality

Sometimes it's hard to imagine how important designing the proper foundation support for a structure can be. The public may assume that the ground we are standing on is pretty much stable and should be able to hold whatever we build on it, without consideration of soil quality. However, there are examples throughout history of structures that were built upon soil conditions that were not suitable for their weight. Perhaps the most famous is the Leaning Tower of Pisa. With better soil quality, it may have been known today as the Tower of Pisa Unfortunately for the constructors, the Tower was built upon a patch of soil that was too soft on one side for the pressure the structure would exert as it's height climbed. The Tower actually had begun leaning during the construction process and had quite a tilt before it was even completed. Over time, builders began to realize that in order to build magnificent structures, and to have them endure over time, they had to understand the geology they were building on. They had to be able to translate an understanding of the soil quality that is not able to be seen into foundation designs that would support even the tallest skyscrapers we build today. Through lots of experimentation, science, engineering and creative solutions, we've been able to evolve our understanding of how to perform a variety of soil tests and how to link that to solid design and construction methods that will support structures as varied as highway bridges and high-rise buildings. As you explore the resources that we've provided in our CPT University, you'll learn about a variety of soil tests and the advantages of each. Tests such as Standard Penetration Tests (SPT), Cone Penetration Tests (CPT) and other forms of testing all have their [...]

By smadi66|December 5th, 2019|Geotechnical Mississippi, Introductory, Cone Penetration, Soil Testing, Geotechnical Louisiana, Geotechnical Maine, Geotechnical Kentucky, Geotechnical Massachusetts, Geotechnical Michigan, Geotechnical Montana, Geotechnical Missouri, Geotechnical Maryland, Geotechnical Minnesota|0 Comments

Soil Quality and Soil Liquefaction

Soil quality typically refers to three characteristics of a soil; the chemical, physical and biological properties. When used as an agricultural term, soil quality is often a measure of the soils ability to produce crops over the long term. However, because the chemical and physical properties of soils are of interest to engineers as well, soil quality is often a term used to describe soil properties of interest to designers, engineers and constructors. The soil quality parameters of most interest are the chemical properties and physical properties. We have featured a closer look into some of the other chemical properties of soils in previous posts, including the ability of soils to conduct electricity, and what this can tell us about types of soil contaminants that might be present. Here, we’re going to delve more deeply into physical soil quality, and one property of certain soils that can be fascinating, but also tragically dangerous. That property is the propensity of certain soil types, under certain conditions to exhibit liquefaction. Liquefaction and Soil Quality Liquefaction, as the name implies, is the term used to describe soil that behaves like a liquid. As you can see from the image above, this can lead to catastrophic outcomes. If the people constructing this building had a better understanding of the impact of soil quality on the stability of the structure, they might have had the opportunity to mitigate the potential damage. So clearly, the susceptibility of a soil to liquefaction is an important indicator of the soil's quality. But what is soil liquefaction? Well, as we noted above, liquefaction is when soil acts like a liquid, but how can this happen? Soil liquefaction most often occurs in loose, sandy soil types where the soil itself is mostly, or completely saturated with water. When this type [...]

By smadi66|December 5th, 2019|Geotechnical Nebraska, Soil Testing, Geotechnical Maine, Geotechnical Massachusetts, Geotechnical Montana, Geotechnical Nevada, Geotechnical Michigan, Geotechnical Missouri, Geotechnical Maryland, Geotechnical Minnesota, Geotechnical Mississippi|0 Comments

Using a Compaction Test to Determine Site Safety Standards

Compaction is an engineering term used to describe the ability of a soil type to be treated with mechanical energy and compressed such that air voids are removed. With individual grains compressed to remove air voids, it becomes more difficult for the soil being compressed to 'settle' further on its own. The strength of the soil in loads other than compression can be increased because the individual particles within the soil become interlocked and friction can become a more important function of the soil behavior. Compacted soil, because air spaces between the particles are reduced has lower hydraulic conductivity (passes water less easily under a given pressure). Why do a Compaction Test? Compaction can be important when high loads such as building foundations may cause a soil to settle over time causing shifting or even collapse. It can be valuable for soil that you want to retain in place, such as along an embankment or behind a retaining wall to be compacted. The compaction process, by increasing the friction in the compacted soil helps to maintain against horizontal slippage which can either result in a landslide off from an embankment or in higher pressure behind a retaining wall, causing it to bow outwards. Because compaction lowers hydraulic conductivity, it can be useful, or even essential in the functioning of earthen dams, drainage ditches and levees. A measurement of compaction is the change in density, or weight per unit volume increase after the soil in question is compacted. That's why sometimes 'compaction' is also called 'densification'. This is actually not a correct designation as 'densification' actually includes both 'compaction' which is described above as well as 'consolidation'. Consolidation involves fluid flow out of the soil being densified, such as when you are treating clay heavy soils. Water is squeezed out from [...]

By smadi66|December 5th, 2019|Soil Testing, Geotechnical Idaho, Geotechnical Louisiana, Geotechnical Maine, Geotechnical Indiana, Geotechnical Massachusetts, Geotechnical Kentucky, Geotechnical Illinois, Geotechnical Maryland, Geotechnical Iowa, Geotechnical Kansas, Introductory|0 Comments