7.2 A specimen of normally consolidated clay (= 28°) was consolidated under achamber-confining pressure of 280 kN/m². For a drained test, by how much docsthe axial stress have to be reduced to cause failure by axial extension?17.3 A normally consolidated clay specimen (= 31°) was consolidated under achamber-confining pressure of 132 kN/m². Failure of the specimen was caused byan added axial stress of 158.1 kN/m in an undrained condition. Determine &u, Afand the pore water pressure in the specimen at failure.>

For pore water pressure we have the concept of effective stress

2 7.3 A normally consolidated clay specimen (d=31°) was consolidated under a chamber-confining pressure of 132 kN/m². Failure of the specimen was caused by an added axial stress of 158.1 kN/m² in an undrained condition. Determine , A and the pore water pressure in the specimen at failure.

2 7.3 A normally consolidated clay specimen (d=31°) was consolidated under a chamber-confining pressure of 132 kN/m². Failure of the specimen was caused by an added axial stress of 158.1 kN/m² in an undrained condition. Determine , A and the pore water pressure in the specimen at failure.

Principles of Geotechnical Engineering (MindTap Course List)

9th Edition

ISBN:9781305970939

Author:Braja M. Das, Khaled Sobhan

Publisher:Braja M. Das, Khaled Sobhan

Chapter12: Shear Strength Of Soil

Section: Chapter Questions

Problem 12.20P

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The figure below shows a 20 m thick layer of normally consolidated clay (ϒt = 18.6 kN/m3) that is one-dimensionally loaded by Δσv = 60 kPa. The clay layer is below a 5 m thick layer of granular fill (ϒt = 19.6 kN/m3), and a dense, compacted glacial till underlies the clay. The water table is located at the top of the clay layer. A 1-D consolidation test is performed on a 3.00 cm thick, doubly drained specimen from the middle of the clay layer. When the stress conditions from the field (including the Δσv = 60 kPa) are applied to this specimen, it takes 1.5 minutes for 60% average consolidation to occur.a. From the lab test data, determine cv for the soil.b. Compute pore water pressure at 20 m depth 7 years after the Δσv is applied to the clay layer. c. Compute the average degree of consolidation 7 years after Δσv application.
A consolidated-drained triaxial test on a normally consolidated clay yielded a friction angle, Φ', of 28°. If the all-around confining pressure during the test was 140 kN/m2, what was the major principal stress at failure?
The figure below shows a 24 m thick layer of normally consolidated clay (ϒt = 18.6 kN/m3) that is one-dimensionally loaded by Δσv = 100 kPa. The clay layer is below a 4 m thick layer of granular fill (ϒt = 19.6 kN/m3), and a dense, compacted glacial till underlies the clay. The water table is located at the top of the clay layer. A 1-D consolidation test is performed on a 2.50 cm thick, doubly drained specimen from the middle of the clay layer. When the stress conditions from the field (including Δσv = 100 kPa) are applied to this specimen, it takes 6 min for 90% average consolidation to occur.a. From the lab test data, determine cv for the soil.b. Compute the pore pressure at depth 22 m before and immediately after the 100 kPa stress is applied.c. At depth 22 m, compute the pore pressure 8.5 years after the 100 kPa is applied.
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