Corey Lee’s Post

Many people assume that those of us who work in geotechnical recruiting know nothing about the field.. BUT........ Fortunately for my candidates and clients, I have a genuine interest in trying to learn and understand the engineering because, prior to this, I worked in the electrical engineering industry for over ten years, so I naturally have an interest in this type of stuff! So recently, I decided to try and get my head around this thing called "liquefaction", and it's safe to say I have a lot more to learn but i have definitely grasped it a little... i think haha. So, imagine you have a jar of sand, and you add some water to it until it's almost full. Now, if you shake the jar really hard, something strange happens—the sand starts acting like quicksand instead of regular sand. That's pretty much what liquefaction is, but it happens with the ground during an earthquake. When the earth shakes with a big earthquake, it sends these powerful waves through the ground, like ripples in a pond. If the ground is made up of certain types of soil, like sandy or silty soil, and there's water in there too, then liquefaction can occur. The shaking makes the soil particles lose their grip on each other, and the water gets squeezed between them. It's like the ground turns into a wobbly, unstable mess! Now, here comes the scary part....... When buildings are constructed on this kind of shaky ground, it can be really risky. The liquefaction makes the ground weaker, and that's bad news for the buildings sitting on top of it. The foundation of a building can sink down, tilt to one side, or even slide around. It's like trying to build a sturdy house on top of jelly... It won't stay steady! In the past, some places have experienced earthquakes where buildings on liquefiable soil got seriously damaged or collapsed. It's like the ground becomes a slippery slope, and the buildings just can't hold on. This can be super dangerous for people inside and around those buildings, and it causes a lot of damage. So to make sure buildings can handle this shaky situation, engineers and builders have to take special precautions. They might use different types of foundations that can handle liquefaction better or find ways to strengthen the ground. It's all about keeping us safe when the earth decides to shake things up. In a nutshell, liquefaction is when the ground turns into quicksand during an earthquake. It's a big problem for buildings because the ground gets all shaky and weak, causing structures to sink, tilt, or slide. But don't worry, clever engineers have ways to protect us and make sure our buildings can withstand the wobbly ground! I'm aware that this doesn't give you a thorough understanding of what liquefaction is, but I just wanted to make an effort to educate someone who, like me, knew nothing about it.

WORKED EXAMPLE | Natural and man-made earth slopes will fail when the external shear stress exceeds the shear strength of the soil. Slope stability analysis is an important aspect of geotechnical engineering design. #civilengineering #geology #geotechnicalengineering #geotechnics #construction #slopestability #foundationengineering #civildesigns https://lnkd.in/ek9eUGAF

https://lnkd.in/gGKT-VAZ What was the real culprit behind this foundation failure – liquefaction or a lack of bearing capacity? In regions prone to earthquakes, like Washington State, liquefaction can significantly affect the stability of our buildings and infrastructure. It's crucial for any foundation repair company operating in these areas to fully grasp the dynamics of liquefaction as it plays a pivotal role in geotechnical engineering and determining the right foundation support system. #raiseandrestore #FoundationFailures #LiquefactionVsBearingCapacity #StructuralEngineering #foundationrepair #foundationrepairs #seismic #washingtonstate #geotechnicalengineering

What is the number of borings you should consider for the geotechnical investigation of a project site ? How deep should the borings go? Find some recommendations in this article. #structville #civilengineering #geotechnicalengineering #geotechnics #foundation #construction #soilmechanics https://lnkd.in/da73GHvq

In an open-cast mine with a failing slope, it's crucial to take immediate mitigation actions to slow down the slope failure process and ensure the safety of personnel and equipment. It's important to note that the effectiveness of mitigation measures depends on the specific geology, slope conditions, and mining practices of the site. Regular and comprehensive slope monitoring is essential to detect early signs of instability and take timely corrective actions. Additionally, conducting detailed geotechnical assessments and involving experts in slope stability analysis can help develop site-specific mitigation strategies that balance safety and operational needs. Here we go: 1. Rockfalls and Rockslides:   - Mitigation: Install rockfall barriers, fences, or catchment systems along the slope to contain falling rocks. Remove loose rocks and create safe zones away from potential rockfall paths.    2. Bench Failure:   - Mitigation: Optimize bench design and slope angles based on the geotechnical properties of the rock. Improve bench stability through proper scaling and removal of overhanging material. 3. Wedge Failure:   - Mitigation: Identify and remove potential wedges through controlled blasting or excavation. Reinforce the slope with rock bolts, mesh, or shotcrete to stabilize potential failure surfaces. 4. Toppling:   - Mitigation: Improve slope geometry to prevent over steepening. Use mechanical or explosive methods to stabilize loose blocks or remove potential toppling masses. 5. Sliding:   - Mitigation: Enhance drainage systems to reduce pore pressure and decrease the likelihood of sliding. Install geosynthetic reinforcements to increase slope stability and resist sliding forces. 6. Creep and Slow Movements:   - Mitigation: Improve drainage to reduce water content and pore pressure in the slope. Utilize vegetation to bind the soil and provide additional stability. 7. Pit Wall Instability:   - Mitigation: Implement comprehensive slope monitoring using radars such as the IDS Georadar, GPS, and inclinometers to detect precursors to instability. Establish emergency response plans and safe zones in case of sudden failure. 8. Slope Subsidence:   - Mitigation: Properly backfill and compact mined-out areas to minimize subsidence. Implement surface support systems to prevent ground collapse. 9. Pit Wall Erosion:   - Mitigation: Apply erosion control measures such as vegetation planting, mulching, and sediment control barriers to protect the pit walls from surface erosion. 10. Hydraulic Failure:   - Mitigation: Develop effective groundwater management strategies to control pore pressure and stabilize slopes. Implement drainage systems to divert excess water away from critical areas. While complete prevention of slope failure may not always be possible, these actions can help mitigate or slow down the different types of slope failure associated with mining pits. PDSA part of Hexagon IDS GeoRadar Hexagon Mining Hexagon AB Niccolo' Coli

Understanding the intricacies of seismic-induced liquefaction is crucial for enhancing the resilience of our infrastructure projects. This recent article from SAICE Civil Engineering Magazine explores groundbreaking research and findings that will undoubtedly shape the future of civil engineering practices. Check out the full article here: https://lnkd.in/ge4p2cAt #CivilEngineering #SeismicLiquefaction #Innovation #Infrastructure #ProjectPartners

The latest issue of Earthquake Engineering Research Institute Spectra (August 2023, Volume 3) includes TWO papers authored by the NIST-funded ATC-134 project team. One of these papers has been chosen as the Editor’s Choice for the August 2023 issue and is available for free public access until the end of September. https://lnkd.in/g8UPzvRv These two papers draw from the NIST GCR 22-917-50 report, Benchmarking Evaluation Methodologies for Existing Reinforced Concrete Buildings, that was published in early 2022 that developed recommendations for improving the existing standards on evaluation and retrofit of reinforced concrete buildings. The recommendations are based on comparison of analytical results to observed performance of eight reinforced concrete structures. The full report is available for download from the National Institute of Standards and Technology (NIST) website. The EERI Spectra papers focus on different aspects of the studies on reinforced concrete structures: Cook et al. (2023) present results from benchmarking nonlinear dynamic procedures and Sen et al. (2023) present results from linear procedures and the FEMA P-2018 methodology. Congrats to the whole ATC-134 team for this honor and recognition! Siamak Sattar Steven McCabe Dustin Cook Russell Berkowitz Wassim Ghannoum Insung Kim Dawn Lehman Abbie Liel laura lowes Adolfo Matamoros Farzad Naeim Rob Smith John Wallace Andrew Sen Tarbin Basnet, P.E. Ariel Creagh, S.E., P.E. Hamid Khodadadi Ayse Hortacsu

I'm excited to share that our paper entitled: "ASCE/SEI 41 assessment of reinforced concrete buildings: Benchmarking linear procedures and FEMA P-2018 with empirical damage observations" was selected as Editor's Choice in the August 2023 issue of the Earthquake Engineering Research Institute's journal, Earthquake Spectra. This and the companion paper on benchmarking ASCE/SEI 41 nonlinear analysis procedures are great summaries of years of work on the ATC-134 project. I encourage you to read both papers AND the cited National Institute of Standards and Technology (NIST) report (which goes into much more detail) if you interface with ASCE/SEI 41 frequently in research or practice.

As a geotechnical engineer, I can assure that shoring systems are no easy feat. Their impact extends beyond just the soil, affecting surrounding structures and life. It's crucial to consider the structural behavior of the shoring and bracing system to predict every possible failure potential. finally no one can bear the losses that result from the collapse of the shoring system. #GeotechnicalEngineering #ShoringSystem #StructuralBehavior

Liquefaction in drained soils can take place far from an epicenter — why? Read Sarah Derouin's piece in Civil Engineering Online, via the #ASCESource and American Society of Civil Engineers. #civilengineering #civilengineers #liquefaction #research #findings