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Abstract
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Introduction
Methodology
Results and Discussions
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Influence of deformation rate on direct shear test results

Profile image of J Y V Shiva BhushanJ Y V Shiva Bhushan

2ND INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS BEHAVIOUR AND CHARACTERIZATION: ICAMBC_2021

https://doi.org/10.1063/5.0072570
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Abstract

Shear strength is the most important property of soil for determining the ground's stability. This paper focuses on the effect of strain rate on shear strength parameters of sands in wet condition. Locally available red soil has been used in this study to assess the role of strain rate at different density. The index properties like specific gravity, compaction characteristics of soil are obtained. Direct shear tests are performed on soils compacted to various densities and each of their results are observed at different shear deformation rates of 1.25, 0.25, 0.05 and 0.01 mm/min. The test results show apparent cohesion increases and decrease with strain rate and the peak friction angle is maximum at a higher strain rate. The magnitude of decrease or increase in each of shear strength parameter varies with relative density.

Figures (10)
FIGURE 1. Grain size distribution curve for Red soil. Locally available Red soil in the Bachupally area, Hyderabad was taken for the current study. The grain size analysis test was conducted as per the IS Code 2720 - Part IV [11]. As per IS-2720-Part-III [12], Part-VII [13], and Part-XIII [14], various laboratory studies on soil like specific gravity, compaction test, and direct shear test were performed.
FIGURE 1. Grain size distribution curve for Red soil. Locally available Red soil in the Bachupally area, Hyderabad was taken for the current study. The grain size analysis test was conducted as per the IS Code 2720 - Part IV [11]. As per IS-2720-Part-III [12], Part-VII [13], and Part-XIII [14], various laboratory studies on soil like specific gravity, compaction test, and direct shear test were performed.
TABLE 1. Geotechnical properties of soil The direct shear test were done on sand samples prepared with water content equal to 12%. The water content fot samples at different densities was fixed based on the targeted relative compaction. The tests were done at three different normal stresses — 50 kPa, 100 kPa and 150 kPa. Prior to carrying out an extensive testing, repeatability in test results was checked by conducting direct shear tests on two identical samples under a normal stress of 50, 10( and 150 kPa, for all samples. Fig 3 shows the shear stress developed on the horizontal plane versus the horizontal displacement of the box for samples subjected to normal stresses of 50, 100 and 150 kPa at 90% RD at ¢ deformation rate of 0.25 mm/min. The direct shear test results clearly show that the test results are repeatable. Further testing was then carried out. In all these cases of drained direct shear testing on fine sand compacted at OMC, the apparent cohesion is because of moisture film around fine sand particles. At lower shearing rate of 0.05
TABLE 1. Geotechnical properties of soil The direct shear test were done on sand samples prepared with water content equal to 12%. The water content fot samples at different densities was fixed based on the targeted relative compaction. The tests were done at three different normal stresses — 50 kPa, 100 kPa and 150 kPa. Prior to carrying out an extensive testing, repeatability in test results was checked by conducting direct shear tests on two identical samples under a normal stress of 50, 10( and 150 kPa, for all samples. Fig 3 shows the shear stress developed on the horizontal plane versus the horizontal displacement of the box for samples subjected to normal stresses of 50, 100 and 150 kPa at 90% RD at ¢ deformation rate of 0.25 mm/min. The direct shear test results clearly show that the test results are repeatable. Further testing was then carried out. In all these cases of drained direct shear testing on fine sand compacted at OMC, the apparent cohesion is because of moisture film around fine sand particles. At lower shearing rate of 0.05
FIGURE 2. Compaction curve of sand.
FIGURE 2. Compaction curve of sand.
FIGURE 3. Shear stress displacement curve at a deformation rate of 0.25mm/min for a 90% RD and 0.01 mm/min, the soil specimens will have an ample time for the readjustment of particles and resistance to shearing depends upon the density.
FIGURE 3. Shear stress displacement curve at a deformation rate of 0.25mm/min for a 90% RD and 0.01 mm/min, the soil specimens will have an ample time for the readjustment of particles and resistance to shearing depends upon the density.
FIGURE 4. Shear strength envelopes for various deformation rates for RD 90%.
FIGURE 4. Shear strength envelopes for various deformation rates for RD 90%.
FIGURE 6. Shear strength envelopes for various deformation rates of RD 50%. FIGURE 5. Shear strength envelopes for various deformation rates for RD 70%.
FIGURE 6. Shear strength envelopes for various deformation rates of RD 50%. FIGURE 5. Shear strength envelopes for various deformation rates for RD 70%.
FIGURE 7. Variation of Apparent Cohesion with RD for various deformation rates. Fig. 7 provides the variation of apparent cohesion with relative density % at various deformation rates.
FIGURE 7. Variation of Apparent Cohesion with RD for various deformation rates. Fig. 7 provides the variation of apparent cohesion with relative density % at various deformation rates.
FIGURE 8. Variation of Angle of internal friction with RD at various deformation rates. CONCLUSIONS
FIGURE 8. Variation of Angle of internal friction with RD at various deformation rates. CONCLUSIONS

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