1. The pressure versus void ratio data determined from a consolidation test on an undisturbed clay specimen are as follows: Applied Pressure (kPa) 20 40 80 160 320 640 1280 320 80 20 0 Void Ratio 0.953 0.948 0.938 0.920 0.878 0.789 0.691 0.719 0.754 0.791 0.890 (a) Plot this pressure versus void ratio data on a semi-logarithmic graph. (b) Determine the equations for the virgin compression curve and for the rebound curve for unloading starting at 1,280 kPa. (c) What are the corresponding compression and recompression indices for this soil? (d) Estimate the stress to which this clay has been preconsolidated. (After A. Casagrande.)

1. The pressure versus void ratio data determined from a consolidation test on an undisturbed clay specimen are as follows: Applied Pressure (kPa) 20 40 80 160 320 640 1280 320 80 20 0 Void Ratio 0.953 0.948 0.938 0.920 0.878 0.789 0.691 0.719 0.754 0.791 0.890 (a) Plot this pressure versus void ratio data on a semi-logarithmic graph. (b) Determine the equations for the virgin compression curve and for the rebound curve for unloading starting at 1,280 kPa. (c) What are the corresponding compression and recompression indices for this soil? (d) Estimate the stress to which this clay has been preconsolidated. (After A. Casagrande.)

Principles of Geotechnical Engineering (MindTap Course List)

9th Edition

ISBN:9781305970939

Author:Braja M. Das, Khaled Sobhan

Publisher:Braja M. Das, Khaled Sobhan

Chapter11: Compressibility Of Soil

Section: Chapter Questions

Problem 11.3P

See similar textbooks

Similar questions

A CID TXC test was performed on a sample of sand. At the end of consolidation, the back pressure was 140 kPa, and the cell pressure was 340 kPa. At failure, the deviator stress was (ơ1 – 03)f = 200 kPa. a. What was the total pore water pressure, u, at failure? b. Calculate the principle effective stresses, ơi' and os', at failure. c. Calculate the friction angle, d', for this soil.
Part #2 Effective Stress (kPa) Void Ratio (%) The following are the results of laboratory consolidation test conducted on clayey soil sample. Determine, graphically, the compression and recompression indices, Cc, C, of this soil. Using Casagrande's method, determine graphically the preconsolidation pressure. 0.891 54 0.866 107 0.841 214 0.802 429 0.737 858 0.653 1716 0.560 3432 0.467
Question 2 The result presented in Table Q2a were obtained from a consolidated drained (CD) triaxial test on a normally consolidated clay sample of 75mm height x 38mm diameter tested at a confining pressure of 50 kPa. Table Q2a. CD triaxial test result Axial strain (%) 1 2 5 10 15 Applied force (kN) 0.01 0.03 0.05 0.08 0.10 Page 3 of 6 (a) Draw the Mohr circle for each stress state in the sample and the total stress path (TSP) throughout the test and determine the slope of the TSP to the horizontal.
A series of unconsolidated undrained (UU) triaxial compression tests have been performed on two "identical" clay specimens. The test results are as follows: Test Number Confining Pressure (kPa)| Deviator Stress at Failure (kPa) 102 96 (i) (ii) 1 2 50 100 Plot the total stress Mohr circles for both specimens at failure (indicate the major and minor principal stresses on the plot). Draw the total stress Mohr-Coulomb failure envelop (i.e., the "p=0" envelop). Estimate the undrained shear strength.
The following results were obtained from a liquid limit test on a clay using the Casagrande cup device. Number of blows Moisture content (%) 6 12 20 28 32 52.5 47.1 43.2 38.6 37.0 a) Determine the liquid limit b) If the natural water content is 38% and the plastic limit is 23%, calculate the liquidity index. c) Would you expect a brittle failure? WHY?
During the 1-dimensional consolidation test, the following measurements were made: Before commencement of the test: Diameter (mm) 49.7 Height (mm) Total mass of specimen (g) 19.9 66.843 After unloading the specimen: Total mass of specimen (g) 60.756 Oven dried mass of specimen (g) 42.197 Total change in dial reading (mm) 3.835 The initial void ratio e, is: O a. 2.55 O b. 2.17 O c. 2.72 O d. 2.94 е. 2.11
The following results were obtained from a set of consolidation test on a specimen of a clay sample taken from a 4.8 m thick clay layer on one of the construction site which are overlaid and underlain by a thick layer of coarse sand. Pressure (kN/m2) Void Ratio after the test 400 0.96 800 0.78 The initial thickness of the tested sample was 19.6 mm with a moisture content of 18%. The sample takes 8 minutes to achieve 25% of consolidation. 1. Estimate the total consolidation settlement of the clay layer based on the variation of the pressure as given in Table 2. Estimate the time to achieve 50% and 90% degree of consolidation and suggest ONE (1) method to accelerate the consolidation process of the above clay layer. Use sketches to support your answers.
9. A consolidated drained test was carried out on a sandy clay under a cell pressure of 250 kPa. A constant back pressure of 120 kPa applied throughout the test. The dimensions of the sample were 76 mm x 38 mm. Addional test data recorded at failure were: Load transducer force = 368 N 3 Measured change in volume = 2.42 x 10 m³ Axial deformation = 2.05 mm Determine the major principal stress, o, at failure. (455 kPa)
Can TRIAXIAL TESTS be performed on sand samples? Briefly explain. The results of an undrained triaxial test on a clay soil sample are given in table below Cell Pressure (kN/m2) 200 400 600 Additional Axial Load at Failure (N) 342 388 465 Each sample, originally 76mm long and 38mm in diameter, experienced a vertical deformation of 5.1mm. Evaluate the stress at failure for each cell pressure given in table above. Draw Mohr Circles and determine the shear strength parameters of the soil.
Please answer all questions based on the scenario Question #1: Considering the water upstream of the dam, a) What will be the seepage loss of that water downstream per year? b) What will the uplift force be on the dam? Question #2: What would the stress in the center of the dam be at the middle of the bottom layer? Consider both the overburden pressure and that due to the loading. Question #3: A sieve analysis was performed on a sample of the top layer of the soil, with the results shown below: Sieve Size (in.) 1/2 3/8 No. 4 No. 8 No. 16 No. 30 No. 40 No. 50 No. 100 No. 200 pan Amount retained (g) 0 0 21.6 39.5 77.6 102.6 89.1 95.6 90.6 60.4 33.3 Do the following: a) Calculate the percent retained and percent passing each sieve, and graph the results on a semi-log graph (you may use the attached chart, or graph in Excel and include with your submission). Then, characterize…
Following are the results of a consolidation test on a sample of undisturbed clay obtained from the field. Pressure ơ' (kN/m²) Final Height of Specimen (mm) 24 10 23.78 20 23.30 50 22.22 100 20.58 200 19.04 400 17.52 800 16.31 17.75 The height of the specimen at the beginning of the test was 24 mm and the area of specimen was 50 cm? volume of specimen was 120 cm³. The mass of dry specimen was 180.4 g. Gs= 2.68. 1. Plot the e-log ơ' curve, 2. Using Casagrande's method, determine the preconsolidation pressure. 3. Calculate the compression index, Cc
A series of identical samples have been tested with drained triaxial test and some of the values are given in the tabulated table 3(Below). Calculate the remaining values as in the blank box. PARAMETER |cell pressure, o3 (kPa) total axial stress, 01 (kPa) pore pressure at failure, u¡ (kPa) |change in volume, Av effective cell pressure, o3' (kPa) effective total axial stress, o,' (kPa) |difference in stress, q (kPa) CD test 150 284 i 1.8 ii i iv O i = 134; ii = 16; iii = 150; iv = 0 O i = 134; ii = 284; iii = 150; iv = 0 O i = 0; ii = 16; iii = 150; iv = 134 O i = 0; ii = 150; iii = 284; iv = 134