The following consolidation test data were obtained from an undisturbed clay specimen. Pressure (kPa) Void ratio 20 0.958 40 0.948 80 0.938 160 0.92 320 0.878 640 0.789 1280 0.691 320 0.719 80 0.754 20 0.791 1 0.89 (a) Plot the void ratio vs. the consolidation pressure curve on semilogarithmic graph paper, and estimate the pre-consolidation pressure o. (b) Determine the compression index C, for the virgin compression and the rebound index C, for the unloading starting at 1280 kPa. (c) Calculate the coefficient of volume compressibility m, for the virgin compression.

The following consolidation test data were obtained from an undisturbed clay specimen. Pressure (kPa) Void ratio 20 0.958 40 0.948 80 0.938 160 0.92 320 0.878 640 0.789 1280 0.691 320 0.719 80 0.754 20 0.791 1 0.89 (a) Plot the void ratio vs. the consolidation pressure curve on semilogarithmic graph paper, and estimate the pre-consolidation pressure o. (b) Determine the compression index C, for the virgin compression and the rebound index C, for the unloading starting at 1280 kPa. (c) Calculate the coefficient of volume compressibility m, for the virgin compression.

Structural Analysis

6th Edition

ISBN:9781337630931

Author:KASSIMALI, Aslam.

Publisher:KASSIMALI, Aslam.

Chapter2: Loads On Structures

Section: Chapter Questions

Problem 1P

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A clay sample underwent a consolidation test in the lab. The clay specimen has drainage on both sides and a height of 25.4 mm. Assume that the clay sample's preconsolidation pressure was less than 150 kPa prior to the consolidation test. The void ratio was 0.96 when the applied effective vertical pressure was 150 kPa. When the vertical effective pressure increased from 150 to 220 kPa, the void ratio at the end of consolidation and compression was 0.88. It was discovered that the sample needed 3 minutes to consolidate by 30%. Following the consolidation test, a swelling/unloading test was conducted, in which the vertical effective stress was lowered from 220 to 150 kPa and the end-of-swelling void ratio was determined to be 0.9. Required a. The compression index of the clay b. The swelling index of the clay C. The height of the clay sample at the end of compression d. The coefficient of consolidation of the clay e. The final height of the clay sample at the end of swelling
A 75 mm diameter clay specimen was consolidated in an oedometer under 200 kPa. At the end of consolidation, the void ratio is 0.863 and the specimen thickness is 18.51 mm. When the stress increment of 200 was added to the current vertical stress of 200 kPa, the specimen consolidated to a thickness of 17.56 mm. Assuming that the clay was normally consolidated under the vertical stress of 200 kPa, find the a) coefficient of volume compressibility in (MPa)^-1 and rounded to the 3rd decimal place.b) and the compression index of the clay rounded to the 2nd decimal place.
Example 4.3 The following compression readings were taken during an oedometer test on a saturated clay specimen (G,=D2.73) when the applied pressure was increased from 214 to 429 kPa: TABLE G 1 Time (min) 1 4 9. 16 25 4 Gauge (mm) Time (min) 5.00 4.67 4.62 4.53 4.41 4.28 4.01 3.75 3.49 36 49 64 81 100 200 400 1440 Gauge (mm) 3.28 3.15 3.06 3.00 2.96 2.84 2.76 2.61 After 1440nmin, the thickness of the specimen was 13.60mm and the water content was 35.9%. Determine the coefficient of consolidation from both the log time and the root time methods and the values of the three compression ratios. Determine also the value of the coefficient of permeability.
Н.W 1. For the one-dimensional consolidation test result shown in Figure below, determine my. 1.0 0.9 0.8 Void ratio 0.7 0.6 0.5 0.4 10,000 Vertical effective stress (log scale) - psf 100 1000 100,000 2- The following readings were taken for an increment of vertical stress of 400 psf in a one-dimensional consolidation test on a saturated clay sample 3 in diameter and 0.75 in thick. Drainage was permitted from the top and bottom boundaries. Determine the coefficient of consolidation using the root time method. Time (min) 0.25 ΔΗ (in) 1 2.25 4 9. 16 25 36 64 144 24 hours 0.0047 0.009 0.0133 0.0169 0.023 0.0268 0.0291 0.03 0.032 0.033 0.035
1. Test A set of 4-in diameter direct shear tests were conducted on a lightly cemented sand. Test results are as shown. Plot the data (units = psf) and determine c' (in psf) and '. How would c' change if there were no cementation? Number 1 2 3 Forces At Failure Normal (lb) 60 120 180 Shearing (lb) 40 71 108 Shear Stresses at Failure Normal (psf) Shearing (psf) 688 458 1375 814 2063 1238 c' = c' = 29.5 degrees 57.3 psf 0.4 psi
The coefficient of permeability of sand at a void ratio of 0.80 is 0.47 mm/s. Estimate the coefficient of permeability of this sand at a void ratio of 0.50.
Below are results from three unconsolidated undrained triaxial tests performed on a fully saturated clay specimen: Test No. 1 2 Minor principal stress (psi) Major principal stress at failure (psi) 10 25 33 22 37 45 Moisture content = 21 % Determine: a) Void ratio (e) of the soil. You may use eS = wG_ (assume Gs = 2.70) %3D b) Deviatory stress at failure for each test trial c) Shear strength parameters (cu and ø). Hint: Sketch the Mohr's circles for the three trials. 3.
Question 15 A consolidated-undrained tri-axial test was conducted on a normally consolidated clay sample and the results are as follows: Chamber confining pressure = 109 kPa, Deviator stress at failure = 98 kPa, Pore Water Pressure = 53 kPa. These results were used to determine the drained friction angle of the soil. Compute the deviator stress (kPa) at failure when the drained test was conducted with the chamber confining pressure changed to 151 kPa. Round off to two decimal places.
|!;9 ELABORATE Try solving the following problem: Practice Problem: The following are the results of a consolidation test on a sample soil: a. Plot the e-log o' curve b. Using Casagrande's method, determine the preconsolidation pressure. c. Calculate the compression index, Cc e 1.1 1.085 1.055 1.01 0.94 0.79 0.63 Pressure, o' (ton /ft²) 0.25 0.50 1.00 2.00 4.00 8.00 16.00
indicate the final answer in 3 decimal places.
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