scholarly journals Simple Method for Prediction of Undrained Shear Strength of Saturated Soil Subjected to Cyclic Loading

2020 ◽  
Vol 15 (2) ◽  
pp. 241-256
Author(s):  
Kazuhiro UENO ◽  
Akira IZUMI ◽  
Antoine DUTTINE ◽  
Sumio YAZAKI ◽  
Toshikazu HORI
Keyword(s):  
Shear Strength ◽  
Cyclic Loading ◽  
Undrained Shear Strength ◽  
Saturated Soil ◽  
Simple Method ◽  
Undrained Shear

Stability threshold for cyclic loading of saturated clay

1989 ◽  
Vol 26 (1) ◽  
pp. 122-131 ◽  
Author(s):  
Guy Lefebvre ◽  
Denis LeBoeuf ◽  
Benoît Demers
Keyword(s):  
Shear Strength ◽  
Cyclic Loading ◽  
Strain Rate ◽  
Undrained Shear Strength ◽  
Triaxial Tests ◽  
Repeated Loading ◽  
Loading Test ◽  
Stability Threshold ◽  
The Stability ◽  
Undrained Shear

This paper presents the results of an experimental investigation performed to study the stability threshold under cyclic (repeated) loading, and the postcyclic static strength of a sensitive clay from the Hudson Bay region. The strain rate and structure effects were also studied by carrying out monotonic and cyclic triaxial tests at both slow and rapid strain rates or frequencies, and at confining pressures above and below the apparent preconsolidation pressure. The stability threshold for both structured and normally consolidated Grande Baleine clay is about 60–65% of the original undrained shear strength measured at the same strain rate as that used in the repeated loading test. The undrained shear strength and the failure envelope remain essentially unchanged if the repeated preloading is kept below the threshold. The clay structure remains unaltered by this preloading. Key words: clay, stability threshold, cyclic loading, earthquake, postcyclic strength.

Study on the Variation Regularity of Shear Strength of Saturated Soft Clay under Cyclic Loading

2011 ◽  
Vol 250-253 ◽  
pp. 2388-2391 ◽  
Author(s):  
Xiao Ping Wang ◽  
Jian Qi Wu
Keyword(s):  
Shear Strength ◽  
Cyclic Loading ◽  
Bearing Capacity ◽  
Triaxial Test ◽  
Soft Clay ◽  
Undrained Shear Strength ◽  
Saturated Soft Clay ◽  
Undrained Shear

The stiffness and shear strength of soft clay attenuate under long-term cyclic loading, resulting in reduced foundation bearing capacity of road. The variation regularity of undrained shear strength of saturated soft clay which is normally consolidated or over consolidated under cyclic loading was studied with two-way vibration triaxial test, and some useful results are obtained.

scholarly journals Post-Cyclic Mechanical Behaviors of Undisturbed Soft Clay with Different Degrees of Reconsolidation

2021 ◽  
Vol 11 (16) ◽  
pp. 7612
Author(s):  
Yuan Lu ◽  
Jian Chen ◽  
Juehao Huang ◽  
Libo Feng ◽  
Song Yu ◽  
...  
Keyword(s):  
Shear Strength ◽  
Cyclic Loading ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Undrained Shear Strength ◽  
Excess Pore Water Pressure ◽  
Undrained Shear ◽  
Excess Pore

Soft soil is often subjected to cyclic loading such as that imposed during storms, under traffic, or in an earthquake. Furthermore, the cyclic-loading-induced excess pore water pressure can be partially dissipated after cyclic loading. Thus, different reconsolidation processes should be considered. A series of static and dynamic triaxial tests were conducted on undisturbed soft soil to determine the post-cyclic mechanical behavior thereof, such as the variation of undrained shear strength, the development of excess pore water pressure, and the evolution of effective stress path. The effects of consolidated confining pressure, cyclic stress ratio, and degree of reconsolidation were analyzed. Results show that the trend of all stress–strain curves is similar under different conditions. The effect of the degree of reconsolidation is such that, with increasing the degree of reconsolidation, the shear strength is enhanced. Meanwhile, compared with undrained shear strength without cyclic loading, the shear strength after cyclic loading with full reconsolidation is increased. These factors also have a significant effect on the undrained shear strength: the greater both the confining pressure and cyclic stress ratio are, the higher the undrained shear strength. A positive excess pore water pressure is always observed during post-cyclic shearing process, irrespective of different factors. The S-shaped effective stress paths under different test conditions are observed and cross the critical state line. The microstructures of undisturbed soil and post-cyclic specimens with different degrees of reconsolidation were quantitatively investigated. Besides that, the degree of influence of different factors on the post-cyclic undrained strength was analyzed. Based on the test results, the undrained shear strength with cyclic load-history was well predicted by existing models.

scholarly journals Effects of compaction on soil undrained shear strength deteriorating during undrained cyclic loading and controlling seismic stability of embankment

2019 ◽  
Vol 92 ◽  
pp. 18003 ◽  
Author(s):  
Antoine Duttine ◽  
Fumio Tatsuoka ◽  
Kazuhiro Ueno
Keyword(s):  
Shear Strength ◽  
Cyclic Loading ◽  
Seismic Analysis ◽  
Undrained Shear Strength ◽  
Seismic Stability ◽  
Triaxial Tests ◽  
Response Analysis ◽  
Total Stress ◽  
Earth Fill ◽  
Undrained Shear

Effects of compaction on the undrained shear strength of saturated earth-fill dam materials are presented. Poorly and well compacted saturated soils may exhibit undrained shear strengths, respectively, significantly lower and higher than corresponding drained shear strength and this trend is amplified as the undrained strength deteriorates by preceding undrained cyclic loading. These features are implemented in a new simplified seismic analysis to evaluate residual deformation of earth-fill dams. The analysis consists of: 1) a modified Newmark sliding block analysis; and 2) a pseudo-static non-linear FEM analysis, both formulated in a unified framework based on the cumulative damage concept, total stress earthquake response analysis and a direct total stress modelling of undrained monotonic and cyclic stress-strain behaviours obtained by triaxial tests. The analysis simulates very well the collapse of an earth-fill dam by the 2011 Off the Pacific Coast of Tohoku Earthquake, Japan, and indicates a substantially higher seismic stability under the same conditions of the newly restored dam completed in 2017. Paramount effects of soil compaction on the seismic stability of earth-filled dam are demonstrated.

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