What are the common indicators or signs of liquefaction in different types of soils or materials?
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Common indicators of liquefaction in various soils include rapid loss of strength, excess pore water pressure generation, soil behaving as a fluid during ground movement, and recovery to initial stiffness post-earthquake cessation . Factors affecting liquefaction include relative density, confining stress, shear strain, and grain size distributions . Indicators like settlement, cyclic stress ratio, and factor of safety are crucial in assessing liquefaction potential in different soils under varying dynamic loading conditions . Laboratory studies have shown that the addition of cement can enhance soil strength and prevent liquefaction initiation . Additionally, the visualization of liquefaction phenomena through manual tapping on soil-water containers and simulation of soil behavior during dynamic excitations provide valuable insights into the liquefaction process .
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| Papers (5) | Insight |
|---|---|
| Common indicators of liquefaction in soils are low factor of safety (<1 for cohesionless, <2 for cohesive), settlement (>9 cm for cohesionless, >6 cm for cohesive), and high Cyclic Stress Ratio. | |
23 Aug 2022 1 Citations | Common indicators of liquefaction in soils include upward movement of rubber balls, downward movement of needle-fixed rubber balls, and instant water level changes in standpipe piezometers during dynamic excitations. |
| Common indicators of liquefaction in soils include increased pore pressure ratio with shear strain, reduced pore pressure ratio with higher confining pressure and relative density, and enhanced strength with cement addition. | |
23 Citations | Common indicators of liquefaction in soils include rapid loss of strength, soil behaving as a fluid during ground movement, and subsequent recovery of stiffness post-earthquake due to dissipation of excess pore water pressure. |
| Common indicators of liquefaction in different soils include loss of strength under cyclic loading, binary response to seismic forces, and varying relative density affecting soil behavior, as discussed in the study. |
Related Questions
What does liquefaction do to buildings in earthquakes?4 answersLiquefaction in earthquakes can have significant effects on buildings. The cyclic shear stress during an earthquake can cause an increase in excess pore water pressure and a loss of shear strength in saturated soil deposits, leading to liquefaction. This can result in excessive strains and a continued loss of shear strength, causing damage to buildings. Liquefaction can induce settlements and tilts in buildings, affecting their performance and function. The presence of liquefiable layers can lead to ground settlements, which can impact the stability of structures, especially those with spread footings. The magnitude of settlement and tilt can be influenced by various factors, such as building height, footing width, peak ground acceleration, and thickness of the liquefiable layer. Numerical simulations have been used to study the effects of liquefaction on buildings, providing insights into the mechanisms and parameters that contribute to settlement and damage.
Was the term soil liquefaction first coined?5 answersSoil liquefaction was first recognized and named in the early 1950s by Mogami and Kubo. However, it gained attention in the geotechnical engineering profession in 1964 after large earthquakes in Niigata, Japan and Alaska, USA. Since then, extensive research on soil liquefaction has been conducted in various seismically active countries, leading to breakthroughs in understanding the mechanics of liquefiable soils and the development of evaluation procedures. Additionally, a simpler method for laboratory testing of soil liquefaction has been developed, which takes into account the pore water pressure buildup during cyclic shearing. Furthermore, an experimental investigation has been undertaken to evaluate the stress conditions required to initiate liquefaction and the influence of various parameters on those stress conditions. In summary, the term soil liquefaction was first coined in the 1950s, but it gained significant attention in the 1960s, and research has since been conducted to better understand and evaluate this phenomenon.
What are the mechanisms that cause liquefaction to affect pile bucking?5 answersThe mechanisms that cause liquefaction to affect pile buckling include the combination of lateral load and axial load, excessive axial loads, and the effect of soil liquefaction on the lateral displacement of the soil. The buckling failure of piles under the combined action of lateral and axial load has received little attention, but it has been found that the buckling load of the pile decreases with an increase in lateral inertial load. The flexural rigidity of the pile, unsupported length ratio, initial imperfections, and degree of soil layer liquefaction also affect the critical buckling load of the pile in liquefiable soil. Additionally, the liquefaction of sloping ground can induce permanent deformation and a bending moment on the pile due to the lateral displacement of the liquefied soil. The current design methods often overlook the buckling effects of piles in liquefiable soils, and a new design approach is proposed to take these effects into account.
What is soil liquefaction?3 answersSoil liquefaction is a phenomenon in which saturated and cohesion-less soils lose their strength and behave like a liquid due to increased pore water pressures and reduced effective stresses caused by dynamic loading, such as earthquakes. It can lead to major failures of civil engineering structures and is often observed in soils with a high content of fine sand grains and fewer clay particles. Site investigations are essential for determining a site's susceptibility to liquefaction, and unused geotechnical reports from previous construction projects can provide valuable information for identifying potential challenges. Various factors, such as ground elevation, groundwater table elevation, SPT N-value, soil type, and fines content, are considered in assessing the liquefaction hazard. Advanced models, including transfer learning and artificial neural networks, have been proposed to predict soil liquefaction potential and improve accuracy in evaluating site quality. The reduction in effective stress in the soil due to the build-up of pore water pressure is the main cause of soil liquefaction or instability.
What are the effects of soil liquefaction?5 answersSoil liquefaction can have devastating consequences for infrastructure and human lives. It occurs when soil loses its strength or stiffness, leading to structural failure, financial loss, and even death. The effects of soil liquefaction include settlement of existing buildings on liquefiable soils, which can be significant and result in damage. The behavior of liquefiable soil is complex and influenced by the bearing pressure of structures. Heavier buildings tend to experience larger settlement, but the settlement ratio may not be proportional to the bearing pressure ratio. The potential for soil liquefaction is influenced by the content of fine grains, with soils high in fine sand and low in clay having a higher liquefaction potential. Increasing the fine grain content decreases the liquefaction potential of the soil. Understanding the mechanisms and effects of soil liquefaction is crucial for mitigating its impact on infrastructure and ensuring environmentally sound development.
How many principle liquefaction processes are there?5 answersThere are several liquefaction processes for natural gas. These include mixed refrigerant processes, cascade processes, expander processes, and nitrogen expander processes.The mixed refrigerant process is the most commonly used, with over 95% of base-load LNG plants operating on this process.The nitrogen expander processes are suitable for small capacities, while the single or dual mixed refrigerant processes are also promising options.The choice of process depends on factors such as efficiency, flexibility, safety, and sensitivity to ship motions.Overall, there are multiple principle liquefaction processes available for LNG production.