Simplified procedure for evaluating soil liquefaction potential
01 Sep 1971-Journal of the Soil Mechanics and Foundations Division (ASCE)-Vol. 97, Iss: 9, pp 1249-1273
TL;DR: Significant factors affecting the liquefaction (or cyclic mobility) potential of sands during earthquakes are identified, and a simplified procedure for evaluating the potential of sand during earthquakes is presented as mentioned in this paper.
Abstract: Significant factors affecting the liquefaction (or cyclic mobility) potential of sands during earthquakes are identified, and a simplified procedure for evaluating liquefaction potential which will take these factors into account is presented Available field data concerning the liquefaction or nonliquefaction behavior of sands during earthquakes is assembled and compared with evaluations of performance using the simplified procedure It is suggested that even the limited available field data can provide a useful guide to the probable performance of other sand deposits, that the proposed method of presenting the data provides a useful framework for evaluating past experiences of sand liquefaction during earthquakes and that the simplified evaluation procedure provides a reasonably good means for extending previous field observations to new situations When greater accuracy is justified, the simplified liquefaction evaluation procedure can readily be supplemented by test data on particular soils or by ground response analyses to provide more definitive evaluations
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TL;DR: In 1996, a workshop sponsored by the National Center for Earthquake Engineering Research (NCEER) was convened by Professors T. L. Youd and I. M. Idriss with 20 experts to review developments over the previous 10 years as mentioned in this paper.
Abstract: Following disastrous earthquakes in Alaska and in Niigata, Japan in 1964, Professors H. B. Seed and I. M. Idriss developed and published a methodology termed the ''simplified procedure'' for evaluating liquefaction resistance of soils. This procedure has become a standard of practice throughout North America and much of the world. The methodology which is largely empirical, has evolved over years, primarily through summary papers by H. B. Seed and his colleagues. No general review or update of the procedure has occurred, however, since 1985, the time of the last major paper by Professor Seed and a report from a National Research Council workshop on liquefaction of soils. In 1996 a workshop sponsored by the National Center for Earthquake Engineering Research (NCEER) was convened by Professors T. L. Youd and I. M. Idriss with 20 experts to review developments over the previous 10 years. The purpose was to gain consensus on updates and augmen- tations to the simplified procedure. The following topics were reviewed and recommendations developed: (1) criteria based on standard penetration tests; (2) criteria based on cone penetration tests; (3) criteria based on shear-wave velocity measurements; (4) use of the Becker penetration test for gravelly soil; (4) magnitude scaling factors; (5) correction factors for overburden pressures and sloping ground; and (6) input values for earthquake magnitude and peak acceleration. Probabilistic and seismic energy analyses were reviewed but no recommen- dations were formulated.
1,766 citations
Cites background from "Simplified procedure for evaluating..."
...Following disastrous earthquakes in Alaska and in Niigata, Japan in 1964, Seed and Idriss (1971) developed and published the basic ‘‘simplified procedure.’’...
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...Seed and Idriss (1971) formulated the following equation for calculation of the cyclic stress ratio: CSR = (t /s9 ) = 0.65(a /g)(s /s9 )r (1)av vo max vo vo d where amax = peak horizontal acceleration at the ground surface generated by the earthquake (discussed later); g = acceleration of gravity;…...
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...1, along with the mean and range of values proposed by Seed and Idriss (1971)....
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TL;DR: In this article, the phenomena of soil liquefaction are described, and suitable definitions and definitions are provided for these phenomena are reviewed and an update of the existing definitions is provided.
Abstract: Soil liquefaction is a major concern for structures constructed with or on sandy soils. This paper describes the phenomena of soil liquefaction, reviews suitable definitions, and provides an update...
1,008 citations
TL;DR: In this article, a simplified procedure for evaluating the liquefaction potential of sand deposits using data obtained from standard penetration tests is reviewed, and the results of this study are then extended to other magnitude earthquakes using a combination of laboratory and field data.
Abstract: The evolution of a simplified procedure for evaluating the liquefaction potential of sand deposits using data obtained from standard penetration tests is reviewed. Field data for sites which are known to have liquefied or not liquefied during earthquakes in the United States, Japan, China, Guatemala, Argentina, and other countries are presented to establish a criterion for evaluating the liquefaction potential of sands in Magnitude 7‐1/2 earthquakes. The results of this study are then extended to other magnitude earthquakes using a combination of laboratory and field data. Available information on the liquefaction resistance of silty sands is also reviewed and a simple procedure for considering the influence of silt content is proposed. A method is presented for using the field data to evaluate the possible magnitude of pore water pressure generation in sands and silty sands which remain stable during earthquake shaking. Finally, the applicability of other in situ field tests, such as the static cone pene...
813 citations
TL;DR: A simplified procedure using shear-wave velocity measurements for evaluating the liquefaction resistance of soils is presented in this paper, which follows the general format of the Seed-Idriss simplified procedure based on standard penetration test blow count.
Abstract: A simplified procedure using shear-wave velocity measurements for evaluating the liquefaction resistance of soils is presented. The procedure was developed in cooperation with industry, researchers, and practitioners and evolved from workshops in 1996 and 1998. It follows the general format of the Seed-Idriss simplified procedure based on standard penetration test blow count and was developed using case history data from 26 earthquakes and >70 measurement sites in soils ranging from fine sand to sandy gravel with cobbles to profiles including silty clay layers. Liquefaction resistance curves were established by applying a modified relationship between the shear-wave velocity and cyclic stress ratio for the constant average cyclic shear strain suggested by R. Dobry. These curves correctly predicted moderate to high liquefaction potential for >95% of the liquefaction case histories and are shown to be consistent with the standard penetration test based curves in sandy soils. A case study is provided to illustrate application of the procedure. Additional data are needed, particularly from denser soil deposits shaken by stronger ground motions, to further validate the simplified procedure.
665 citations
TL;DR: In this paper, semi-empirical procedures for evaluating the liquefaction potential of saturated cohesionless soils during earthquakes are re-examined and revised relations for use in practice are recommended.
651 citations
Cites background or methods from "Simplified procedure for evaluating..."
...STRESS REDUCTION COEFFICIENT, dr Seed and Idriss (1971) introduced the stress reduction coefficient dr as a parameter describing the ratio of cyclic stresses for a flexible soil column to the cyclic stresses for a rigid soil column, as illustrated in Figure 1....
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...The original simplified procedure (Seed and Idriss 1971) for estimating earthquake-induced cyclic shear stresses continues to be an essential component of the analysis framework, although there have been a number of refinements to the various components of this framework....
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...…(6) would provide a sufficient degree of accuracy for engineering applications and it is recommended that these equations be used in lieu of the figure originally published by Seed and Idriss (1971) or any of the equations that have been derived over the past 30 or so years based on that figure....
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