Liquefaction-induced Lateral Spread Displacement PDF Download

Author: T. Leslie Youd
Publisher:
ISBN:
Category : Shear strength of soils
Languages : en
Pages : 62

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Author: Allison Theresa Faris
Publisher:
ISBN:
Category :
Languages : en
Pages : 912

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Author: Liangcai He
Publisher:
ISBN:
Category :
Languages : en
Pages : 886

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Author: Steven F. Bartlett
Publisher:
ISBN:
Category : Earth movements
Languages : en
Pages : 258

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Author: Michael Vernon Little
Publisher:
ISBN:
Category :
Languages : en
Pages : 234

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Book Description
Liquefaction-induced lateral spreading represents an important geohazard during earthquakes due to the significant displacements that are induced. These movements have the potential to cause significant damage to both the overlying infrastructure (e.g., buildings, bridges), as well as embedded infrastructure (e.g., pipelines). The objectives of this research are to use field observations and numerical simulations of lateral spreading to elucidate the important factors influencing lateral spread displacements. High resolution displacement data from the 2011 Christchurch earthquake are used with surface and subsurface data to evaluate the effectiveness of state-of-practice predictive models for lateral spread displacements and to identify topographic and geotechnical factors that have a significant influence on lateral spreading displacements. The results show that limitations in the existing lateral spread displacement predictive models are in need of improvements and that special care should be taken when evaluating lateral spreading displacements at sites with a topographic terrace and multiple free-faces. A set of 132 numerical models of free-face lateral spread sites are analyzed to evaluate the influence of the height of the free-face, the thickness of liquefiable layers, sloping ground behind the free-face, and the presence of a topographic terrace. The results indicate that the main factor driving lateral spread displacements is the combined height of the free-face and liquefiable soil layer thickness. Sloping ground behind the free-face can increase the displacements by as much as 1 m in the zone 50-100 m from the free-face. The presence of a topographic terrace at a distance of up to 400 m from the free-face can result in more than 0.5 m of increased displacements between the free-face and terrace. The results of these analyses are also used to develop a framework for predicting the surface displacement profile behind the free-face of a lateral spread site. Another set of 456 finite element simulations are performed to investigate the effects of earthquake intensity measures (IM) on the triggering of liquefaction and on lateral spreading displacements. The IMs that are best able to distinguish between triggering and non-triggering of liquefaction are cumulative absolute velocity with a minimum acceleration threshold of 50 cm/s2 (CAV50), normalized dissipated energy [equation], and Arias intensity (I [subscript a]). The IM with the most potential for predicting lateral spreading displacements is cumulative absolute velocity (CAV, defined without an acceleration threshold). Considering only the part of the motion after which liquefaction is triggered (IM [subscript post]) as the predictor of lateral spread displacements results in only a marginal improvement in predictive capacity. The largest increase to predictive capacity after selecting the appropriate IM comes from including information about the geometry of the site

Author: National Academies of Sciences, Engineering, and Medicine
Publisher:
ISBN: 9780309440271
Category :
Languages : en
Pages : 350

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Book Description
Earthquake-induced soil liquefaction (liquefaction) is a leading cause of earthquake damage worldwide. Liquefaction is often described in the literature as the phenomena of seismic generation of excess porewater pressures and consequent softening of granular soils. Many regions in the United States have been witness to liquefaction and its consequences, not just those in the west that people associate with earthquake hazards. Past damage and destruction caused by liquefaction underline the importance of accurate assessments of where liquefaction is likely and of what the consequences of liquefaction may be. Such assessments are needed to protect life and safety and to mitigate economic, environmental, and societal impacts of liquefaction in a cost-effective manner. Assessment methods exist, but methods to assess the potential for liquefaction triggering are more mature than are those to predict liquefaction consequences, and the earthquake engineering community wrestles with the differences among the various assessment methods for both liquefaction triggering and consequences. State of the Art and Practice in the Assessment of Earthquake-Induced Soil Liquefaction and Its Consequences evaluates these various methods, focusing on those developed within the past 20 years, and recommends strategies to minimize uncertainties in the short term and to develop improved methods to assess liquefaction and its consequences in the long term. This report represents a first attempt within the geotechnical earthquake engineering community to consider, in such a manner, the various methods to assess liquefaction consequences.

Author: Siang Huat Goh
Publisher:
ISBN:
Category : Piling (Civil engineering)
Languages : en
Pages : 702

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Author: Sorin S. Secara
Publisher:
ISBN:
Category :
Languages : en
Pages : 68

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Liquefaction is a significant earthquake hazard that can generate large horizontal displacements associated with lateral spreading and these displacements cause considerable damage. To improve our understanding of liquefaction-induced lateral spreading and the models that can be used to predict the associated displacements, the collection of high quality field data on lateral spreading displacements is essential. Remote sensing techniques, in particular optical image correlation using satellite imagery, can be used for this purpose. This thesis investigates optical image correlation of satellite images as a remote sensing technique for this purpose using images from the 2010-2011 Canterbury earthquake sequence in New Zealand. Optical image correlation uses two optical images – one before and one after the investigated event – to measure displacements that have occurred between the time of the two image acquisitions. The correlation analysis calculates the horizontal displacement at a specified spacing, and the displacements are post-processed and filtered to attain the final displacement field. The displacement results from optical image correlation agreed favorably with qualitative field observations of the severity of liquefaction and lateral spreading, as well as the general crack patterns along the Avon River. A more quantitative comparison was performed using field measured displacements along four linear transects that extended perpendicular from the Avon River. The displacements from optical image correlation also agreed favorably with the field measured displacement profiles, although the optical image correlation displacements somewhat larger than the field measurements. This discrepancy occurs because field measurements are based on discrete measurements of crack width, while the optical image correlation are based on average displacements over larger areas and include displacements associated with ductile movements that may not result in cracking. The results from this research show that optical image correlation of satellite imagery pairs can provide accurate and detailed measurements of horizontal displacements due to liquefaction and lateral spreading. This approach can be used to create more complete and detailed databases of liquefaction-induced movements, which can be used to improve current predictive models for lateral spread displacements. Future post-earthquake investigations and research should make use of optical image correlation to document the displacements associated with liquefaction.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 7

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Author: Ricardo Dobry
Publisher:
ISBN:
Category : Earth resistance
Languages : en
Pages :

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