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Traversing California, the Rocky and Coastal Mountain Ranges dictate the geological composition of the landscape. Located on the San Andreas fault system, the area experiences frequent mini quakes and the occasional larger one. A side effect of the quakes are landslides. Despite the hazards, California is recognized for its incredible beauty. Just some of the sights people travel from around the world to see includes Glacier Point, Zabriskie Point, Morro Rock, and Bodega Head.

California Issues Maps of Earthquake Faults to Avoid ‘Potentially Devastating’ Damage to New Buildings

Source: State Issues Maps of Earthquake Faults to Avoid 'Potentially Devastating' Damage to New Buildings - Times of San Diego The Rose Canyon Fault system. Courtesy County News Center Maps released Thursday of earthquake-prone areas are intended to ensure new construction in San Diego does not take place atop dangerous quake faults. Developed by the California Geological Survey, the regulatory Alquist-Priolo Earthquake Fault Zone maps detail where local governments must require site-specific geologic and engineering studies for proposed developments to ensure this hazard is identified and avoided. Generally, new construction for human occupancy must be set back 50 feet from the active surface trace to avoid faults that may break the surface. “Surface fault rupture is the easiest earthquake-related hazard to avoid because you can see the evidence of where it has occurred,” said Steve Bohlen, acting state geologist and head of CGS. “Surface fault rupture means that one side of a fault is moving either vertically or horizontally in relation to the other side. The deformation that movement causes is potentially devastating to buildings and infrastructure.” Two maps of revised Earthquake Fault Zones have been prepared for the Rose Canyon Fault where it comes onshore in Coronado, traversing the San Diego area to the northwest and going back offshore near La Jolla. Each of the maps covers a roughly 60-square-mile quadrangle of territory. The Alquist-Priolo Act was passed into law following the 1971 magnitude 6.6 San Fernando earthquake, which caused extensive surface ruptures that damaged buildings. Not every large earthquake, though, causes surface fault rupture. For example: the Loma Prieta Earthquake of 1989 devastated the Bay Area without breaking the surface. However, the 1992 Landers Earthquake in San Bernardino County caused surface ruptures along 50 miles, with displacements ranging from one inch to 20 feet. “Since the [...]

Dynamic behaviors of wind turbines under wind and earthquake excitations

Source: Dynamic behaviors of wind turbines under wind and earthquake excitations: Journal of Renewable and Sustainable Energy: Vol 13, No 4 Source: How Do Wind Turbines Respond to Winds, Ground Motion During Earthquakes? - AIP Publishing LLC A new study investigates the combined effect of wind and earthquake forces to assess the dynamic behavior of wind turbines. The demand for renewable energy is nowadays at its peak. Wind power is a great source of clean energy and is harvested via wind farms placed in numerous regions across the world. This has led to some winds farms being established in earthquake-prone regions making it important to assess the combined excitation under wind and earthquake forces. In the US, these wind farms are most commonly seen in Alaska, Arkansas, California, Idaho, Illinois, Kentucky, Missouri, Montana, Nevada, Oregon, South Carolina, Tennessee, Utah, Washington, and Wyoming. The study, recently published in the Journal of Renewable and Sustainable Energy, aims at establishing a numerical model that will integrates both seismic, wind, and operation forces of wind turbines to evaluate the performance of the wind turbines. This is referred to as the "fully coupled model". Such models have been tested before but the research team emphasizes that a solid interpretation of the results is still missing. The authors studied a 5MW wind turbine subjected to a combination of wind load and input ground motion with the latter being retrieved from a list of earthquake records. The study provides some interesting findings. The results from the sophisticated numerical models suggest that the wind that acts as a dynamic load for the wind turbine also exerts a damping effect on the response of the structure. In particular, when shaking is strong, the energy absorbed due to the aerodynamic damping is higher than the actual wind loading generates hence, the [...]

By kk42|September 24th, 2021|Geotechnical Idaho, Geotechnical Montana, Geotechnical Nevada, Geotechnical Oregon, Geotechnical South Carolina, Geotechnical Kentucky, Geotechnical Utah, Geotechnical Tennessee, Geotechnical Washington, Geotechnical Illinois, Geotechnical Wyoming, Geotechnical Missouri, Earthquakes, Geotechnical Arkansas, Geotechnical California, Geotechnical Alaska|0 Comments

University of Nevada, Reno scientists and engineers collaborating on seismic survey for earthquakes

Source: University of Nevada, Reno scientists and engineers collaborating on seismic survey for earthquakes | University of Nevada, Reno University of Nevada, Reno scientists and engineers install equipment at Reno Fire Department's Station 5 on Mayberry Drive as part of a seismic study using fiber-optic cable that runs six miles from downtown Reno to west of Reno. A team of scientists and engineers from the University of Nevada, Reno are installing earthquake sensors above ground along a six-mile stretch of an existing fiber-optic telecommunication cable buried under Reno to develop a rigorous and efficient system for subsurface imaging at the large scale, and detecting earthquakes using laser and fiber-optic technology. "We'll be recording seismic signals generated by passing planes, trains and automobiles along the six-mile stretch of currently unused, buried optical fiber that runs west from Virginia Street along California Avenue and on to Mayberry Drive," Scott Tyler, professor of geological sciences and a leading expert in fiber-optic/laser sensing systems, said. "As the vibrations from the transportation system pass through the underlying geology, it causes a very small change in the optical fiber’s length, which can be recorded from the start of the fiber on South Virginia Street, using a laser-based system called Distributed Acoustic Sensing or DAS." The team, led by Elnaz Seylabi, an assistant professor in the civil and environmental engineering department, is also installing three-component high-resolution seismometers along the cable in the study area to compare traditional methods with the new DAS technology that sends a pulse of laser light through the cable and measures the perturbations in the backscattered light from every point along the cable. The fiber optic system is sensitive enough to detect footsteps as well as jet airplanes that fly by. "Instead of using thousands of geophones to measure ground vibration [...]

By kk42|September 23rd, 2021|Los Angeles, Tanaina, Las Vegas, Earthquakes, San Diego, Lakes, Reno, San Jose, Kalifornsky, Henderson, Geotechnical Alaska, San Francisco, North Las Vegas, Anchorage, Long Beach, Sparks, Juneau, Fresno, Carson City, Fairbanks, Sacramento, Elko, Badger, Oakland, Boulder City, Knik-Fairview, Santa Ana, Mesquite, College, Anaheim, Fallon, Geotechnical California, Wasilla, Geotechnical Nevada, Geotechnical Virginia|0 Comments

Soil Nail Walls Design and Construction

Source: Soil Nail Walls - Design and Construction -NEW (7003IW2022) INSTRUCTOR: Naresh Samtani, Ph.D., P.E., D.GE, F.ASCE Participants will have access to the virtual workshop video archives and materials for 60 days from the start day of the workshop. Virtual Workshop Brief Using a collaborative and interactive learning approach, this virtual workshop will help you understand the design and construction aspects for soil nail walls. You will learn newer design approaches based on the LRFD platform that is the basis for guidelines for soil nail walls by the American Association of State Highway and Transportation Officials (AASHTO) and the Federal Highway Administration (FHWA). The workshop will help you assimilate the design and construction aspects through active participation by frequent interactions throughout the workshop and real-time expert feedback. The interactions will facilitate a better understanding of the nuances of the newer design principles which would help you avoid costly design errors in real-world projects. In between the two live sessions, attendees will independently work on an application (e.g., exercises) or a reflection (e.g., reading) assignment. Learning Outcomes Upon completion of this course, you will be able to: Explain the terminology for soil nail walls Explain design of soil nail walls using principles of limit state design Explain the essential elements of construction Recognize construction procedures and influence on wall design and performance Explain the importance and concepts of nail testing Identify necessary characteristics of software tools Explain corrosion considerations Discuss facing (shotcrete) analysis Identify the necessary information on plans and specifications Benefits for Participants Become familiar with the latest limit state design approaches and standards for soil nail walls Avoid common pitfalls and costly errors in analysis and design Be able to categorize and streamline limit state evaluation Recognize the importance of considering construction as part of overall design process Assessment of [...]

By kk42|September 23rd, 2021|Geotechnical North Carolina, Geotechnical South Dakota, Geotechnical West Virginia, Geotechnical Texas, Geotechnical Ohio, Geotechnical USA, Conferences, Geotechnical Illinois, Geotechnical US, Geotechnical Alaska, Geotechnical Arizona, Geotechnical Michigan, Geotechnical Arkansas, Geotechnical Missouri, Geotechnical California, Geotechnical Maryland, Geotechnical Louisiana, Geotechnical Connecticut, Geotechnical Nevada, Geotechnical Florida, Geotechnical New Jersey, Geotechnical Kansas, Geotechnical Rhode Island|Comments Off

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 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, 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 Massachusetts, Geotechnical Indiana, Geotechnical Wisconsin, Geotechnical South Carolina, Geotechnical USA, Geotechnical Montana, Soil Testing, Geotechnical Minnesota, Geotechnical South Dakota|0 Comments

Earthquake in Haiti Triggers Landslides

Source: Hundreds of landslides followed Haiti earthquake, Tropical Depression Grace - The Washington Post Source: Earthquake in Haiti Triggers Landslides After a 7.2 magnitude earthquake hit southwestern Haiti on the Saturday morning of August 14th, hundreds of landslides threatened the area. Landslides are one of the biggest causes of earthquake-related deaths. In 2010, the earthquake near Haiti's capital, Port-au-Prince, killed roughly 200,000 people and led to tens of thousands of landslides. The earthquake was centered about eight miles southeast of Petit-Trou-de-Nippes at a depth of six miles. USGS reported at least 150 landslides south of the epicenter, to the west of the town L'Asile. The mountains and south of Beaumont experienced hundreds more. “Even though a lot of the central and western parts of the epicentral area have been obscured by cloud cover, we haven’t seen too many landslides in the gaps in the clouds,” wrote Robert Emberson, a landslide researcher at NASA’s Goddard Space Flight Center. “We anticipate that the bulk of the landsliding (at least from the earthquake) is in the [Pic Macaya] National Park.” The National Hurricane Center predicted 5 to 10 inches of rain in Haiti with a possibility of up to 15 inches. Flash flooding, mudslides, and landslides were all expected following the rain. “With the ongoing tropical storm rainfall, further landslides are likely,” wrote Emberson. “In particular, landslide material mobilized by the earthquake may be washed downstream as debris flows. We will continue to monitor changes over the coming days to assess the exacerbated impact of the rainfall and provide situational awareness.” Landslides and earthquakes have recently in multiple parts of the world. Denali Park, Sichuan China, Battle Creek Michigan, and a recent Monsoon in India are just four of the most recently affected areas.

By kk42|September 22nd, 2021|Geotechnical California, Geotechnical Colorado, Geotechnical Oregon, Geotechnical Washington, Earthquakes, Landslides|0 Comments

Environmental Regulations Changing China’s Hydropower Stations

Source: China’s Thousands of Small Dams Struggle to Stay Afloat Chen Tai’an poses for a photo atop the Hongsha Hydropower Station dam in Liuyang, Hunan province, 2021. Diao Fanchao for Sixth Tone For decades, rural areas along the Yangtze River depended on small hydropower stations. Now, amid rising ecological costs and safety concerns, the government wants to make them more sustainable. Early in April, continuous rain lashed the central city of Liuyang, Hunan province for days. As the Yangtze River Basin entered its major flood season and its banks swelled, Chen Tai’an stood inside the hydropower plant he partly owns, listening to the rumble of its turbines. He says it’s the best time of the year to generate hydropower since most turbines operate at full capacity. But this year has been different. Chen says his Hongsha Hydropower Station’s annual revenue fell by more than 30,000 yuan ($4,600) as its output was cut by 100,000 kilowatts per hour. The reduced power generation stemmed from new, and more stringent, government guidelines for maintaining “ecological water flow” — the level and quality of water in rivers to sustain the local ecosystem. According to a 2018 government policy mandated for small hydropower stations, Chen couldn’t store water during the dry spell between August and March — meaning river water could no longer be fully stored to generate electricity as in previous years. So he was given until August of last year to install a floodgate on the dam to release one-tenth of the annual runoff into the river, with which he complied. “All that water wasted… such a shame,” says Chen, looking at the river and furrowing his brow. He’s still pondering what the government meant by “ecological water flow.” To him, all river water is a valuable resource, and using turbines to turn it into [...]

By kk42|September 22nd, 2021|Geotechnical New York, Geotechnical Oregon, Geotechnical Washington, Uncategorized, Geotechnical Alabama, Geotechnical USA, Geotechnical US, Geotechnical California|0 Comments

Sichuan China Earthquake

Source: Sichuan, China: Earthquake leaves three dead and 60 injured - CNN An earthquake in China's southwestern province of Sichuan left at least 3 people dead and 60 injured on September 16th, according to China's state-run media. Local authorities put the quake at 6.0-magnitude, while the US Geological Survey (USGS) put it at 5.4-magnitude on an 8-point scale. The quake hit in the early hours of the morning, with the epicenter located about 52 kilometers (32.3 miles) southwest of Yongchuan district in Chongqing, with an initial depth of 10 kilometers, according to USGS. The earthquake left at least 1,221 collapsed houses and more than 3,000 severely damaged homes, according to the Global Times. "I woke up to the tremor and saw the chandelier in my room swinging dramatically and the writing desk was shaking," one resident, surnamed Tang, told the Global Times. "It's been a long time since an earthquake of this magnitude has occurred." Chinese authorities launched rescue efforts in the morning, with the provincial government activating a level 2 response, the second highest in China's four-tier earthquake emergency response system, according to Xinhua. Luzhou City, home to about five million residents, was among the hard-hit areas. Thousands of soldiers and emergency workers have been sent on rescue efforts, along with rescue equipment, medical supplies, makeshift surgical vehicles and heavy machinery. Tents have been set up for evacuees in a nearby village. Experts say a more serious earthquake is unlikely, though there may be aftershocks, Xinhua reported. Sichuan is located along one of several seismic belts in China, which makes it prone to earthquakes. One local employee in Luzhou told the Global Times that though residents are used to earthquakes, they are usually of a lower magnitude -- and Thursday's quake was much stronger than average. A number of [...]

By kk42|September 21st, 2021|Geotechnical Arizona, Geotechnical California, Geotechnical Montana, Geotechnical Nevada, Geotechnical Washington, Geotechnical Wyoming, Earthquakes, Geotechnical USA, Geotechnical US|0 Comments

3D Finite Element Analysis of a Contiguous Pile Wall

Source: 3D Finite Element Analysis of a Contiguous Pile Wall Source: RS3 | 3D Finite Element Software For Advanced Analysis | Rocscience 3D Finite Element Analysis of a Contiguous Pile Wall Introduction This article provides a brief summary of a 3D finite element analysis carried out using RS3 to model a contiguous pile retaining wall at the site of a proposed commercial development in the UK. The development site is located on sloping ground approximately 35 m from a motorway cutting. Due to the sloping topography of the site, cut and fill earthworks are to be undertaken to form a level development plateau upon which a large warehouse is to be built. This will require the construction of a circa 400 m long contiguous pile retaining wall to support the ground along the site’s upslope boundary where ground levels will be reduced by up to 8.4 m. Wall Design A plan showing the arrangement of the piles and the 2.0 m wide by 0.8 m deep capping beam is shown in Figure 1. The main 900 mm diameter piles are 17 m long and are staggered in a zigzag arrangement at 0.25 m offsets either side of the capping beam centerline. Interspersed mid-way between the main piles are 600 mm diameter infill piles. The infill piles are located along the capping beam centerline and are 11 m long. Figure 1: Pile and capping beam arrangement Ground Conditions The ground conditions are summarized in Figure 2 which shows a 2D section perpendicular to the wall alignment at the location where the retained height attains its maximum value of 8.4 m. The succession of strata comprises a veneer of clay-rich Glacial Till overlying Coal Measures bedrock. The Coal Measures bedrock is dominated by siltstone and mudstone and has been divided into three [...]

By kk42|September 21st, 2021|Geotechnical Texas, Dallas, Geotechnical Pennsylvania, Pittsburgh, Geotechnical Minnesota, Minneapolis, Geotechnical US, Geotechnical Arizona, Phoenix, Geotechnical California, Pile Foundation, Los Angeles|Comments Off

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 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, 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|Comments Off

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