A soil profile is shown in Figure 1. Determine the total consolidation settlement of the clay layer 7 years after the completion of primary consolidation settlement. (Take necessary data from Figure 2 and Figure 3. (Note: Time for completion of primary settlement is 2.5 years) Also, determine the time to complete 60% consolidation of this type of soil; if the coefficient of consolidation is 0.053 m²/yr. Ag= Last two digits of Roll/Registration No. (kN/m²) 6 ft Ya= 15.1 kN/m³ Ya= 14.2 kN/m O = 12% Degree of Saturation, S = 75% G, = 2.68 8 ft 13 ft Ysat= 19.7 kN/m³ Sand Clay Figure 1: Soil Profile

A soil profile is shown in Figure 1. Determine the total consolidation settlement of the clay layer 7 years after the completion of primary consolidation settlement. (Take necessary data from Figure 2 and Figure 3. (Note: Time for completion of primary settlement is 2.5 years) Also, determine the time to complete 60% consolidation of this type of soil; if the coefficient of consolidation is 0.053 m²/yr. Ag= Last two digits of Roll/Registration No. (kN/m²) 6 ft Ya= 15.1 kN/m³ Ya= 14.2 kN/m O = 12% Degree of Saturation, S = 75% G, = 2.68 8 ft 13 ft Ysat= 19.7 kN/m³ Sand Clay Figure 1: Soil Profile

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 11.15P

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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.
C 5. For the soil profile given below, assume that the primary consolidation settlement for the clay layer is completed in 3 years. Estimate the secondary consolidation settlement for the clay layer at the end of 10 years. Yw= 10kN/m³, Ca = 0.03 t 1m 1.5m 2m Groundwater table 0.5m 90 = 100kPa BXL = 2m x 4m Sand y = 17.0 kN/m³ Sand Ysat = 19.0 kN/m³ = Normally consolidated Clay Ysat = 20 kN/m³ eo = 0.7 Cs= 0.09 Cc = 0.2
A site is underlain by a saturated clay layer with thickness = 5m. A sample extracted from the center of the clay layer was recently tested for consolidation parameters. The results indicate that the compression index is 0.33, the recompression index is 0.09, and the void ratio is 1.2. The results also indicate that the layer is normally consolidated. Calculate the preconsolidation stress of the clay. Express your answer in kPa. Note: this is a short problem; read the problem statement carefully. Use unit water weight = 10 kN/m3.
The vertical soil profile shown below is loaded with a uniform surcharged pressure of 60 kPa on the ground surface. If the water table is at the ground surface, calculate the total consolidation settlement at the ground surface? Note: Clay Properties from laboratory consolidation on clay sample taken from these clay layers are: - Ot - Uw 7 o=(20x3)-(9.8x3) z o=30.6 kPa oc=80 kPa, Cs 1+ eo Sol: 1- Clay layer -1 (consider mid depth) oo + Ao' =30.6+60=90.6 kPa - σ' + Δσ'>σ 907 80 Therefore, the soil is overconsolidated 1 Sc 9.4 mm... Clay layer -2 ( Cc 1+eo = 0.01 oven حمل = 0.1 -6.0 m 2m- خارف 80.0 Sc= 0.01 x 1 x log. 30.6 20 ميسي تأثريا لا سلام Ю Δισ S. - (H/ (Glog & + Culog ²% + An) Sc 1+% oc Sand Y = 20 kN/m² Clay layer -1 7 = 20 kN Sand Yar = 20 kN m² Clay layer -2 Sand Yar = 20 kN Ys 20 kN m Rock +0.1 x 1.0 x log; 90.6 80.0 (20) 3x20) + (6 +22) + (20 +22A VA -3
For the soil profile given below, assume that the primary consolidation settlement for the clay layer is completed in 3 years. Estimate the secondary consolidation settlement for the clay layer at the end of 10 years. Yw= 10kN/m³, Ca= 0.03 1m 1.5m 2m BxL= 2m x 4m Groundwater table 0.5m 90 = 100kPa Sand y = 17.0 kN/m³ Sand Ysat 19.0 kN/m³ a retaining wall are shown in Normally consolidated Clay Ysat 20 kN/m³ eo = 0.7 Cs=0.09 Cc = 0.2
3. A stratum of normally consolidated clay is 25 feet thick and the water content is measured as 50% (Gs=2.7). Consolidation tests on undisturbed samples of the clay indicate Ce = 0.68. On top of the clay is 5 feet of sand with a total unit weight of 120 pcf. To build a parking lot, 8 feet of fill is now placed on top of the sand. Tests on the fill indicate that the average water content is 10% and the average dry unit weight is 115 pef. The water table is located 2 ft below the ground surface. Calculate the settlement of the clay due to the added weight of the fill. Treat the clay as one layer and compute the stresses and change in void ratio at mid-depth in the clay.
5. For the soil profile given below, assume that the primary consolidation settlement for the clay layer is completed in 3 years. Estimate the secondary consolidation settlement for the clay layer at the end of 10 years. Yw= 10kN/m³, Ca = 0.03 1m 1.5m 2m Groundwater table 0.5m BXL = 2m x 4m Sand y = 17.0 kN/m³ 90 = 100kPa Sand Ysat = 19.0 kN/m² Normally consolidated Clay Ysat = 20 kN/m³ eo = 0.7 Cs = 0.09 Cc = 0.2 -
The laboratory consolidation data for an undisturbed clay specimen are as follows: e1 = 1.12 P₁ = 90 kPa e2 = 0.90 P2 = 450 kPa 1. Compute the value of the compression index. 2. Compute the value of the swell index assuming it is equal to 1/6 the value of the compression index. 3. Compute the void ratio for a pressure of 600 kPa. 4. Compute the coefficient of compressibility. 5. Compute the value of the coefficient of volume compressibility.
In the soil profile shown below, if the water table changes from level WT0 to level WT1 permanently, what is the change in the ground surface elevation in mm in the long term after primary consolidation is completed? Assume that the clay layer is initially normally consolidated. Use a single clay layer in your calculations and positive value for settlement. (Acceptable tolerance = 4%)
The laboratory consolidation test is conducted on a clay sample. The following data results were obtained P1 =55 kPa P2 = 130 kPa e1= 0.95 e2= 0.80 Thickness of the sample of clay= 35mm Time for 50% consolidation = 3.0 min Tv= 0.197 a. Find the coefficient of volume compressibility b. Determine the coefficient of consolidation if a sample of clay was drained on both sides c. Compute the hydraulic conductivity of the clay
Compressibililty: Consolidation and Settlement of Soil 500 kN 4m x 3m 3.5m Dry Sand = 15 kN/m Yary Sand Y = 17 kN/m³ 1.5m Clay = 19 kN/m Ysat e. = 1.0 LL = 50% 4.5m 2. Find the total consolidation settlement of the clay 4 years after the completion of primary consolidation settlement. The time for the completion of the primary consolidation settlement is 3 years. Ca = 0.020 (E; = 18 MPa, Poisson's Ratio = 0.20, I = 1.0)
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.)