Equivalent number of uniform cycles versus earthquake magnitude relationships for fine-grained soils

2019 ◽  
Vol 56 (11) ◽  
pp. 1596-1608
Author(s):  
Priyesh Verma ◽  
Ainur Seidalinova ◽  
Dharma Wijewickreme
Keyword(s):  
Large Earthquake ◽  
Earthquake Magnitude ◽  
Undisturbed Soil ◽  
Experimental Database ◽  
Cyclic Shear ◽  
Fine Grained ◽  
Evaluation Procedures ◽  
Magnitude Scaling ◽  
Equivalent Number ◽  
Time Histories

In current geotechnical seismic design practice, the empirical correlation between equivalent number of uniform cycles (Neq) of shaking and earthquake magnitude (Mw) forms an integral part of liquefaction potential evaluation. This relationship, in turn, is used to derive the magnitude scaling factors that are commonly used in field-based liquefaction evaluation procedures. The Neq versus Mw relationship for liquefaction assessment was examined for fine-grained soils using time-histories in the range 5 < Mw ≤ 9, especially including strong ground motion time-histories from the latest subduction zone earthquakes with Mw > 8.0. The experimental database available from cyclic direct simple shear tests conducted on natural fine-grained soils retrieved from undisturbed soil sampling was used to obtain the cyclic shear resistance weighting curves for the study. The work presented herein has contributed to further improving the current models used to represent magnitude scaling factor (MSF) values for large earthquake magnitudes and the functional dependency of this parameter on soil type. The MSF–Mw curve derived for low-plastic Fraser River Delta silt lies in-between the MSF curves derived for clean sand and clay, resonating with the inferences that have been made that the silt behavior can neither be considered sand-like nor clay-like.

Earthquake Magnitude Scaling Using Peak Ground Velocity Derived from High-Rate GNSS Observations

2020 ◽  
Vol 92 (1) ◽  
pp. 227-237
Author(s):  
Rongxin Fang ◽  
Jiawei Zheng ◽  
Jianghui Geng ◽  
Yuanming Shu ◽  
Chuang Shi ◽  
...  
Keyword(s):  
Rapid Determination ◽  
Seismic Station ◽  
Scaling Law ◽  
Large Earthquake ◽  
Earthquake Magnitude ◽  
New Method ◽  
High Rate ◽  
Peak Ground Velocity ◽  
Absolute Deviation ◽  
Magnitude Scaling

Abstract Rapid response to destructive tsunami and seismic events requires rapid determination of the earthquake magnitude. We propose a new method that employs peak ground velocities (PGVs) derived from Global Navigation Satellite System (GNSS) data to estimate earthquake magnitudes. With a total of 1434 records from 22 events as the constraints, we perform the regression and obtain a PGV scaling law for magnitude determination. The advantage of the new method is that the PGVs are extracted from the GNSS velocity waveforms, which can be easily computed using broadcast GNSS ephemeris. In contrast, the peak ground displacement (PGD) depends on a sophisticated high-precision GNSS-processing subject to external correction data, realization of which cannot be kept robust constantly, especially in real time. The results show that the PGV magnitudes agree with reported moment magnitudes with mean absolute deviation of 0.26 magnitude units for the 22 events and also agree well with the PGD magnitude. We further demonstrate that GNSS-derived PGV and the modified Mercalli intensity values can be consistent with their counterparts from the U.S. Geological Survey ShakeMap products and therefore the GNSS-derived PGVs have the potential to be included in the ShakeMap as a complementary constraint, especially in areas with sparse seismic station coverage for large earthquake.

scholarly journals Earthquake magnitude scaling using seismogeodetic data

2013 ◽  
Vol 40 (23) ◽  
pp. 6089-6094 ◽  
Author(s):  
Brendan W. Crowell ◽  
Diego Melgar ◽  
Yehuda Bock ◽  
Jennifer S. Haase ◽  
Jianghui Geng
Keyword(s):  
Earthquake Magnitude ◽  
Magnitude Scaling

Effect of Parameters on Equivalent Number of Cycles Using ‎Nonlinear Seismic Site Response Analysis

2011 ◽  
Vol 255-260 ◽  
pp. 2365-2369
Author(s):  
Emad Gheibi ◽  
Mohammad Hosein Bagheripour
Keyword(s):  
Site Response ◽  
Time History ◽  
Current Approach ◽  
Earthquake Magnitude ◽  
Soil Liquefaction ◽  
Site Response Analysis ◽  
Response Analysis ◽  
Nonlinear Site Response ◽  
Equivalent Number ◽  
Number Of Cycles

The concept of equivalent number of uniform stress cycles, is essential for assessment of soil liquefaction potential. In this regard, various procedures are used to convert random acceleration time history to uniform cycles having amplitude of 0.65 of peak acceleration. Equivalent number of cycles (Neq) defines equivalent energy generated by harmonic loading as that imposed by irregular motion during an earthquake. Neq is assumed to be a function of earthquake magnitude. Over the past years, in accordance with development in methods of soil liquefaction evaluation, various methods have been proposed to determinate equivalent number of cycles. In particular, parameters like site to source distance (r), have been related directly to Neq. In this study, more than 80 earthquake records have been investigated and their Neqs are assessed using energy approach and nonlinear site response analysis. It is shown that equivalent number of cycles is related to earthquake magnitude (M), r and depth of originated signals. Unlike previous methods which result in scatter in output data, current approach has led to more uniform and consistent results for each earthquake.

scholarly journals From Word To Sense Embeddings: A Survey on Vector Representations of Meaning

2018 ◽  
Vol 63 ◽  
pp. 743-788 ◽  
Author(s):  
Jose Camacho-Collados ◽  
Mohammad Taher Pilehvar
Keyword(s):  
Theoretical Background ◽  
Comprehensive Overview ◽  
Lexical Meaning ◽  
Fine Grained ◽  
Knowledge Based ◽  
Evaluation Procedures ◽  
Word Level ◽  
Wide Range ◽  
Sense Representation ◽  
Vector Representations

Over the past years, distributed semantic representations have proved to be effective and flexible keepers of prior knowledge to be integrated into downstream applications. This survey focuses on the representation of meaning. We start from the theoretical background behind word vector space models and highlight one of their major limitations: the meaning conflation deficiency, which arises from representing a word with all its possible meanings as a single vector. Then, we explain how this deficiency can be addressed through a transition from the word level to the more fine-grained level of word senses (in its broader acceptation) as a method for modelling unambiguous lexical meaning. We present a comprehensive overview of the wide range of techniques in the two main branches of sense representation, i.e., unsupervised and knowledge-based. Finally, this survey covers the main evaluation procedures and applications for this type of representation, and provides an analysis of four of its important aspects: interpretability, sense granularity, adaptability to different domains and compositionality.

scholarly journals NEW NATIONAL STANDARD FOR SELF-COMPACTING CONCRETE MIXES

2021 ◽  
pp. 30-40
Author(s):  
Simon KAPRIELOV ◽  
Andrey SHEYNFELD ◽  
Igor ARZUMANOV ◽  
Igor CHILIN
Keyword(s):  
Reinforced Concrete ◽  
Precast Concrete ◽  
Test Methods ◽  
National Standard ◽  
Light Weight ◽  
Self Compacting Concrete ◽  
Fine Grained ◽  
Evaluation Procedures ◽  
Concrete Mixtures ◽  
Slump Flow

The information about the new national standard GOST R «Self-compacting concrete mixtures. Specifications», developed by the «Research Institute for Concrete and Reinforced Concrete» named after A.A. Gvozdev, of JSC «Research Center of Construction», is presented. The standard applies to ready-to-use selfcompacting concrete mixtures of heavyweight, fine-grained, light-weight and reactive powder concretes, as well as fiber reinforced concretes, for the production of monolithic or precast concrete structures and products, the shape and reinforcement of which makes it difficult to place and compaction of an ordinary concrete mixture. The standard establishes new terms and definitions, types and designations, uniform requirements for new technological characteristics (slump-flow, segregation, viscosity and flowability), acceptance rules and test methods, production and transportation processes, control and evaluation procedures conformity of quality indicators of self-compacting concrete mixes.

scholarly journals THE APPLICABILITY OF DISINTEGRATION TESTS FOR COHESIVE ORGANIC SOILS

2015 ◽  
Vol 23 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Anne-Katrin GROßE ◽  
Stefan CANTRÉ ◽  
Fokke SAATHOFF
Keyword(s):  
Boundary Conditions ◽  
Large Scale ◽  
Erosion Resistance ◽  
Construction Materials ◽  
Aggregate Stability ◽  
Organic Soils ◽  
Fine Grained ◽  
Evaluation Procedures ◽  
Dredged Materials ◽  
Top Soil

The use of ripened fine-grained organic dredged materials as construction materials, e.g. as top soil on slopes such as landfills or dikes, is an important contribution to environmental engineering science. The materials are legally considered a waste and need to be beneficially re-used. Therefore, not only standard geotechnical parameter shave to be determined but also their erosion resistance which is a particularly critical environmental parameter. There is a variety of different tests to determine the flow dependent erosion resistance of soils, such as the erosion function apparatus (Briaud et al. 2001). In this study, however, the focus lays on the aggregate stability as an indicator for the erosion resistance under static loading, which can be determined using wet sieving and disintegration tests. The disintegration tests after Weißmann (2003) and Endell (RPW 2006) have a similar setup; however, the specific boundary conditions for the tests as well as the evaluation procedures are different. Weißmann proposed his test to determine the erosion stability of dike cover materials while the Endell test should be used for mineral sealing liners in navigation channels. In this study both tests have been used to evaluate the aggregate stability of fine-grained organic dredged materials that have been installed in large-scale research dike facilities and in the recultivation layers of different landfills. The materials showed good visual performance with respect to rainfall induced erosion so far; however, problems in determining erosion and aggregate stability indices limit the value of the studies: both disintegration tests investigated have major limitations with respect to the organic soils tested. Particularly the evaluation methods are not suitable for the soils but also some boundary conditions are critical and are discussed in this paper. The gained knowledge is a valuable basis for the development of standard characterisation methods for dredged materials in environmental and geotechnical applications.

Reversing Cyclic Elastic Demands on Structures during Earthquakes and Applications to Ductility Requirements

1984 ◽  
Vol 1 (1) ◽  
pp. 7-32 ◽  
Author(s):  
Virgilio Perez ◽  
A. Gerald Brady
Keyword(s):  
Elastic Limit ◽  
Epicentral Distance ◽  
Large Earthquake ◽  
Earthquake Magnitude ◽  
Maximum Response ◽  
Plastic Behavior ◽  
Maximum Displacement ◽  
Long Period ◽  
Elastic Demands ◽  
Number Of Cycles

The study of all earthquake-induced oscillator response peaks from selected records shows how these peaks decrease in amplitude with the number of cycles attaining them. These studies concentrate on the ratio between the peak amplitudes of response experienced throughout the duration of a given number of cycles and the maximum response. The ratio shows a trend that is fairly independent of the structure's period, the epicentral distance, and the earthquake magnitude. If during a very large earthquake a structure is forced into displacements beyond the elastic limit it must withstand them successfully with well-designed ductility. For long-period structures, these inelastic displacements, if assumed to result from idealized elasto-plastic behavior, are approximately equal to the elastic displacements under study. The trends shown here consequently indicate that the amplitudes of the elasto-plastic displacements still attained after two, four, or eight cycles, remain at levels that are appreciably high percentages of the maximum displacement.

Cyclic shear response of fine-grained mine tailings

2005 ◽  
Vol 42 (5) ◽  
pp. 1408-1421 ◽  
Author(s):  
Dharma Wijewickreme ◽  
Maria V Sanin ◽  
Graham R Greenaway
Keyword(s):  
Shear Strength ◽  
Simple Shear ◽  
Mine Tailings ◽  
Mechanical Response ◽  
Constant Volume ◽  
Confining Stress ◽  
Cyclic Shear ◽  
Shear Response ◽  
Fine Grained ◽  
Direct Simple Shear

The mechanical response of three different types of fine-grained mine tailings is examined using data from constant-volume cyclic direct simple shear (DSS) tests. Under cyclic DSS loading, fine-grained tailings typically exhibit a cumulative decrease in effective stress along with progressive degradation of shear stiffness. The observed shear strain development due to cyclic mobility is similar in form to that of the previously observed cyclic shear response for natural silts. The cyclic resistance ratio (CRR) of laterite tailings is observed to increase with an increase in the initial effective confining stress (σ′vc). For this material, the dilative tendency due to stress densification seems to have overridden the contractive tendency due to the increase in confining stress. In contrast, the CRR of copper–gold–zinc tailings is insensitive to the initial effective confining stress, suggesting a response similar to that of normally consolidated clay. The postcyclic maximum shear strength ratio (Su-PC /σ′vc) obtained from constant-volume monotonic DSS tests is noted to increase with a decrease in the void ratio. For the fine-grained tailings considered in this study, the liquefaction susceptibility predicted using commonly used empirical criteria is not always in agreement with the liquefaction triggering determined from cyclic DSS tests.Key words: tailings, liquefaction, cyclic stress ratio, postcyclic shear strength, direct simple shear testing.

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