3.36. A site consists of 3 m thick loose sand with an in-situ void ratio of 0.75. The laboratory tests showthat the maximum and minimum void ratios of thesand are 0.85 and 0.50, respectively. Based on thefield SPT value of 5, this soil will be liquefiableat an earthquake magnitude of 6.5. Vibrocompactionmethod with granular backfill is proposed to densifythis soil. Assume the diameter of granular columnsis 0.75 m. To minimize the liquefaction potential, thest densified soil should have an SPT N value of 20, whichcorresponds to the relative density of 70%. Assume theground settles 40 mm after the densífication. Find therequired spacing of granular columns.om21

3.36. A site consists of 3 m thick loose sand with an in- "situ void ratio of 0.75. The laboratory tests show that the maximum and minimum void ratios of the sand are 0.85 and 0.50, respectively. Based on the b or field SPT value of 5, this soil will be liquefiable at an earthquake magnitude of 6.5. Vibrocompaction method with granular backfill is proposed to densify to this soil. Assume the diameter of granular columns is 0.75 m. To minimize the liquefaction potential, the t densified soil should have an SPT N value of 20, which h u corresponds to the relative density of 70%. Assume the A ground settles 40 mm after the densification. Find the oira required spacing of granular columns.

3.36. A site consists of 3 m thick loose sand with an in- "situ void ratio of 0.75. The laboratory tests show that the maximum and minimum void ratios of the sand are 0.85 and 0.50, respectively. Based on the b or field SPT value of 5, this soil will be liquefiable at an earthquake magnitude of 6.5. Vibrocompaction method with granular backfill is proposed to densify to this soil. Assume the diameter of granular columns is 0.75 m. To minimize the liquefaction potential, the t densified soil should have an SPT N value of 20, which h u corresponds to the relative density of 70%. Assume the A ground settles 40 mm after the densification. Find the oira required spacing of granular columns.

Fundamentals of Geotechnical Engineering (MindTap Course List)

5th Edition

ISBN:9781305635180

Author:Braja M. Das, Nagaratnam Sivakugan

Publisher:Braja M. Das, Nagaratnam Sivakugan

Chapter11: Ground Improvement

Section: Chapter Questions

Problem 11.6P

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. A site consists of 3m thick loose sand with an insitu void ratio of 0.75. The laboratory tests show that the maximum and minimum void ratios of the sand are 0.85 and 0.50, respectively. Based on the f ield SPT value of 5, this soil will be liquefiable at an earthquake magnitude of 6.5. Vibrocompaction method with granular backfill is proposed to densify this soil. Assume the diameter of granular columns is 0.75m. To minimize the liquefaction potential, the densified soil should have an SPTNvalueof20,which corresponds to the relative density of 70%. Assumethe ground settles 40 mm after the densification. Find the required spacing of granular columns.
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