Seismic Response and Cyclic Behavior of Sands PDF Download

Author: Lynn Ann Salvati
Publisher:
ISBN:
Category :
Languages : en
Pages : 608

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Author: Kenji Mori
Publisher:
ISBN:
Category : Sand
Languages : en
Pages : 114

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Author: Harry Bolton Seed
Publisher:
ISBN:
Category : Earthquake engineering
Languages : en
Pages : 90

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Author: Abdulaziz Osman Abdelkadr
Publisher: BoD – Books on Demand
ISBN: 3737610185
Category : Science
Languages : en
Pages : 274

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Book Description
In this study experimental and numerical investigations have been carried out with the emphasis on studying the behaviour and liquefaction state of typical silty sand sampled from the Mekelle area in Ethiopia under monotonic and cyclic undrained loadings. Experiments have been carried out to measure the pore pressure accumulation, deformation characteristics and related effective stress paths. A numerical model was then used to simulate the behaviour and liquefaction state associated with the changes in the stress-strain-pore pressure levels by means of the finite element method (FEM) using the FE code Tochnog (Tochnog Professional Company 2021).

Author: Susumu Iai
Publisher:
ISBN:
Category : Earthquake engineering
Languages : en
Pages : 312

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Author: Kōji Tokimatsu
Publisher:
ISBN:
Category : Buildings
Languages : en
Pages : 90

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Author: Marshall L. Silver
Publisher:
ISBN:
Category : Materials
Languages : en
Pages : 298

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Book Description
The volume change characteristics and the dynamic stress-strain properties of dry sand subjected to cyclic shear strains have been investigated and used to check the applicability of a simple method for predicting the vertical settlements due to compaction in layers of dry cohesionless soils subjected to seismic loading conditions. Dynamic testing of a medium quartz sand, performed by repeated load simple shear equipment, indicated that the shear modulus increased slightly with increasing numbers of cycles and with increasing relative density and decreases significantly with increasing values of shear strain amplitude. Modulus values determined near the upper limit of shear strain amplitude that might be expected to be induced by seismic shaking (0.1 percent) were as much as 40 percent lower than modulus values obtained at the lowest values of shear strain that were investigated (0.01 percent). (Author).

Author: Aikaterini Ziotopoulou
Publisher:
ISBN:
Category : Earthquake engineering
Languages : en
Pages : 0

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Book Description
The development of the sand plasticity model PM4Sand (Versions 2 and 3) for geotechnical earthquake engineering applications is presented. The motivation behind this work is twofold. The first goal is to have a constitutive model that is applicable to the wide range of conditions encountered in geotechnical engineering practice, is easy to calibrate utilizing the limited data that are usually available and can reasonably approximate the behaviors of interest. The second goal is to provide an extensive documentation of the capabilities and limitations of the model. The PM4Sand plasticity model is built upon the basic framework of the stress-ratio controlled, critical state compatible, bounding surface plasticity model for sand presented by Dafalias and Manzari (2004). A series of modifications and additions to the model were incorporated by Boulanger (2010; Version 1) and further herein (Version 2 and Version 3) to improve its ability to approximate the stress-strain responses important to geotechnical earthquake engineering practice; in essence, the model is calibrated at the equation level to provide for better approximation of the trends observed in empirical correlations commonly used in practice. Each stage of its development has been guided by consecutive cycles of formulation, validation and calibration against the whole body of available data (case histories, lab, centrifuge and shake table tests) on the cyclic behavior of sands both at the element and at the system level. The formulation of PM4Sand Version 2 for geotechnical earthquake engineering applications is presented followed by its calibration and implementation. A generalized calibration of the constitutive model is presented which attempts to produce drained and undrained, monotonic and cyclic responses under a broad range of stress conditions that are reasonably consistent with the behaviors expected based on engineering correlations to commonly available in-situ test data (i.e., SPT, CPT and Vs data). Simulated single element responses are compared to design correlations to illustrate the efficacy of the model modifications and evaluate the model’s performance. The constitutive model is shown to be relatively easy to calibrate and provide reasonable responses for key liquefaction behaviors. The numerical implementation as a user defined material for use in a two-dimensional explicit finite difference program is described. The formulation of PM4Sand Version 3 for improved modeling of post-liquefaction reconsolidation strains is presented. Modifications are introduced that provide a means for improved modeling of post-liquefaction reconsolidation strains after the end of strong shaking in a nonlinear deformation analysis. The methodology of the approach along with the calibration is presented, followed by a comparison of the response computed for a field case history. A review is presented on the performance of a number of constitutive models in reasonably predicting liquefaction effects under sloping ground conditions. Example results from undrained cyclic DSS tests on clean sands under zero and nonzero static shear stress ratio conditions are presented and findings from past experimental studies for these types of loading conditions are reviewed. Examples are presented of the performance of selected constitutive models in modeling the observed experimental results. It is shown that they all have certain limitations and that the effect of sloping ground conditions is particularly difficult to simulate. Finally, the formulation of PM4Sand Version 3 is further updated to better account for the effects of sloping ground conditions and irregular cyclic loading on liquefaction behaviors and thus improve simulations of liquefaction-induced deformations of sloping ground. Existing laboratory test data are reviewed and new experimental data from undrained cyclic Direct Simple Shear (DSS) lab tests of liquefiable sand under sloping ground conditions subjected to irregular cyclic loading are introduced. Evidence from the tests shows that it is the effect of loading history on the dilatancy and stiffness characteristics of the response that is not properly captured by the model. The modifications made in Version 3 include a revised dependency of dilatancy and plastic modulus on the fabric tensor and its history. These modifications are introduced using the irregular cyclic DSS testing to illustrate the motivations for the changes in the constitutive equations. Finally, two examples of calibration are presented: one against a specific lab test result for a single sand and one against an engineering correlation describing trends observed for many sands across a broader range of relative densities, confining stresses, and loading conditions. The updated formulation in Version 3 of the model is shown to better approximate liquefaction behaviors for sloping ground conditions.

Author: Robert T. Donaghe
Publisher: ASTM International
ISBN: 0803109830
Category : Anisotropy
Languages : en
Pages : 896

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Book Description
"Although the triaxial compression test is presently the most widely used procedure for determining strength and stress-deformation properties of soils, there have been no books published on triaxial testing since the 1962 second edition of the landmark work The Measurement of Soil Properties in the Triaxial Test by Bishop and Henkel. It is apparent there is a need to document advances made in triaxial testing since publication of Bishop and Henkel's book and to examine the current state of the art in a forum devoted solely to triaxial testing. Because of increasing versatility brought about by recent developments in testing techniques and equipment, it is also important that the geotechnical profession be provided with an up-to-date awareness of potential uses for the triaxial test."--Overview.

Author: Shuying Wang
Publisher: Springer
ISBN: 9811070830
Category : Science
Languages : en
Pages : 167

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Book Description
This book gathers the main research findings on monotonic, cyclic and postcyclic shear behavior of low-plasticity. Drawing on the low-plasticity silt from the Mississippi River Valley, it determines that the silt’s critical state line can be changed due to liquefaction, and thus offers valuable insights and reference data for further investigations on soil mechanics and engineering applications to verify the above research findings. Low-plasticity silt with a plasticity index of less than 10, though commonly found around the world, nonetheless differs greatly from sand and clay in terms of its shear behavior. Failure to take into account the differences in shear characteristics between silt, clay and sand will lead to overconservative designs of offshore structures. In particular, dynamic loading from earthquakes, trains and ocean waves can set off the liquefaction of low-plasticity silt, and with it, major disasters and losses of properties. Additionally, some civil infrastructures have failed not only due to cyclic loading during an earthquake, but also due to reduction of shear strength or stiffness after that.