❖ Problem 3 A sieve analysis was performed on a soil sample, and the results are tabulated below (Table 3). Table 3: Sieve Analysis – Experimental Data (Problem 3) U.S. Standard Opening (mm) Mass Retained (g) Sieve No. 4 4.75 0.0 0 2.00 0.0 20 0.85 0.0 40 0.425 13.5 60 0.25 43.5 100 0.15 75.4 140 0.106 147.6 200 0.075 168.2 PAN <0.075 230.5 A hydrometer analysis was then performed on the fines content of the soil sample (the remaining mass in the pan). The results of the hydrometer analysis are provided in Table 4 below. Table 4: Sieve Analysis - Results (Problem 3) Particle %Finer Diameter (mm) 0.072 78.20% 0.046 58.20% 0.034 50.40% 0.026 42.80% 0.017 38.10% 0.012 35.40% 0.007 30.20% 0.004 25.70% 0.0032 22.90% 0.0024 20.90% 0.0017 18.20% 0.0012 14.5% Analyze the experimental data and present the results. Be sure to include the following: a) Tabulation of sieve analysis experimental results for %Retained, %RetainedcUM, and %Finer b) Tabulation of hydrometer analysis results for modified %finer c) Plot the grain size distribution curve for granular and fine soil content d) Determine the percentage of gravel, sand, silt, and clay according to AASHTO

❖ Problem 3 A sieve analysis was performed on a soil sample, and the results are tabulated below (Table 3). Table 3: Sieve Analysis – Experimental Data (Problem 3) U.S. Standard Opening (mm) Mass Retained (g) Sieve No. 4 4.75 0.0 0 2.00 0.0 20 0.85 0.0 40 0.425 13.5 60 0.25 43.5 100 0.15 75.4 140 0.106 147.6 200 0.075 168.2 PAN <0.075 230.5 A hydrometer analysis was then performed on the fines content of the soil sample (the remaining mass in the pan). The results of the hydrometer analysis are provided in Table 4 below. Table 4: Sieve Analysis - Results (Problem 3) Particle %Finer Diameter (mm) 0.072 78.20% 0.046 58.20% 0.034 50.40% 0.026 42.80% 0.017 38.10% 0.012 35.40% 0.007 30.20% 0.004 25.70% 0.0032 22.90% 0.0024 20.90% 0.0017 18.20% 0.0012 14.5% Analyze the experimental data and present the results. Be sure to include the following: a) Tabulation of sieve analysis experimental results for %Retained, %RetainedcUM, and %Finer b) Tabulation of hydrometer analysis results for modified %finer c) Plot the grain size distribution curve for granular and fine soil content d) Determine the percentage of gravel, sand, silt, and clay according to AASHTO

Principles of Geotechnical Engineering (MindTap Course List)

9th Edition

ISBN:9781305970939

Author:Braja M. Das, Khaled Sobhan

Publisher:Braja M. Das, Khaled Sobhan

Chapter2: Origin Of Soil And Grain Size

Section: Chapter Questions

Problem 2.1CTP: Three groups of students from the Geotechnical Engineering class collected soil-aggregate samples...

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Three groups of students from the Geotechnical Engineering class collected soil-aggregate samples for laboratory testing from a recycled aggregate processing plant in Palm Beach County, Florida. Three samples, denoted by Soil A, Soil B, and Soil C, were collected from three locations of the aggregate stockpile, and sieve analyses were conducted (see Figure 2.35). (a) (b) Figure 2.35 (a) Soil-aggregate stockpile; (b) sieve analysis (Courtesy of Khaled Sobhan, Florida Atlantic University, Boca Raton, Florida) a. Determine the coefficient of uniformity and the coefficient of gradation for Soils A, B, and C. b. Which one is coarser: Soil A or Soil C? Justify your answer. c. Although the soils are obtained from the same stockpile, why are the curves so different? (Hint: Comment on particle segregation and representative field sampling.) d. Determine the percentages of gravel, sand and fines according to Unified Soil Classification System.
Refer to Problem 2.C.1. Results of the sieve analysis for Soils A, B, and C are given below. To obtain a more representative sample for further geotechnical testing, a ternary blend is created by uniformly mixing 8000 kg of each soil. Answer the following questions. a. If a sieve analysis is conducted on the mixture using the same set of sieves as shown above, compute the mass retained (as a percentage) and cumulative percent passing in each sieve. b. What would be the uniformity coefficient (Cu) and the coefficient of gradation (Cc) of the mixture?
A hydrometer test has the following result: Gs = 2.65, temperature of water = 26 C, and L = 10.4 cm at 45 minutes after the start of sedimentation (see Figure 2.25). What is the diameter D of the smallest-size particles that have settled beyond the zone of measurement at that time (that is, t = 45 min)? Figure 2.25 ASTM 152H type of hydrometer placed inside the sedimentation cylinder (Courtesy of Khaled Sobhan, Florida Atlantic University, Boca Raton, Florida)
Repeat Problem 2.8 using the following data. 2.8 The following are the results of a sieve and hydrometer analysis. a. Draw the grain-size distribution curve. b. Determine the percentages of gravel, sand, silt and clay according to the MIT system. c. Repeat Part b according to the USDA system. d. Repeat Part b according to the AASHTO system.
Following results are obtained for a liquid limit test using a fall cone device. Estimate the liquid limit of the soil and the flow index.
Repeat Problem 2.14 with the following values: Gs = 2.75, temperature of water = 21C, t = 88 min, and L = 11.7 cm. 2.14 A hydrometer test has the following result: Gs = 2.65, temperature of water = 26 C, and L = 10.4 cm at 45 minutes after the start of sedimentation (see Figure 2.25). What is the diameter D of the smallest-size particles that have settled beyond the zone of measurement at that time (that is, t = 45 min)? Figure 2.25 ASTM 152H type of hydrometer placed inside the sedimentation cylinder (Courtesy of Khaled Sobhan, Florida Atlantic University, Boca Raton, Florida)
The subsurface characteristics for a highway pavement rehabilitation project in the southeastern United States are shown in a boring log in Figure 5.13. The highway structure consists of the asphalt pavement underlain by four different soil strata up to a depth of 20 ft, after which the boring was terminated. Some data on the grain size and plasticity characteristics are also provided for each stratum. Perform the following tasks: 1. Determine the AASHTO soil classification and the group index (GI) for each layer. 2. Determine the most probable group symbols and group names for the various layers according to the Unified soil classification system. Use Table 5.3 and the soil characteristics given in the boring log.
The following data were obtained by conducting liquid limit and plastic limit tests on a soil collected from the site. Liquid limit tests: Plastic limit test: PL = 19.3% a. Draw the flow curve and determine the liquid limit. b. Using the Casagrande plasticity chart (Figure 4.21), determine the soil type.
Since laboratory or field experiments are generally expensive and time consuming, geotechnical engineers often have to rely on empirical relationships to predict design parameters. Section 6.6 presents such relationships for predicting optimum moisture content and maximum dry unit weight. Let us use some of these equations and compare our results with known experimental data. The following table presents the results from laboratory compaction tests conducted on a wide range of fine-grained soils using various compactive efforts (E). Based on the soil data given in the table, determine the optimum moisture content and maximum dry unit weight using the empirical relationships presented in Section 6.6. a. Use the Osman et al. (2008) method [Eqs. (6.15) through (6.18)]. b. Use the Gurtug and Sridharan (2004) method [Eqs. (6.13) and (6.14)]. c. Use the Matteo et al. (2009) method [Eqs. (6.19) and (6.20)]. d. Plot the calculated wopt against the experimental wopt, and the calculated d(max) with the experimental d(max). Draw a 45 line of equality on each plot. e. Comment on the predictive capabilities of various methods. What can you say about the inherent nature of empirical models?
Results from a liquid limit test conducted on a soil are given below. a. Determine the liquid limit of the soil. b. If it is known that the PI = 6.5, what would be the plastic limit of the soil? c. Determine the liquidity index of the soil if win situ = 23.8%
The properties of seven different clayey soils are shown below (Skempton and Northey, 1952). Investigate the relationship between the strength and plasticity characteristics by performing the following tasks: a. Estimate the plasticity index for each soil using Skemptons definition of activity [Eq. (4.28)]. b. Estimate the probable mineral composition of the clay soils based on PI and A (use Table 4.3) c. Sensitivity (St) refers to the loss of strength when the soil is remolded or disturbed. It is defined as the ratio of the undisturbed strength (f-undisturbed) to the remolded strength (f-remolded)) at the same moisture content [Eq. (12.49)]. From the given data, estimate f-remolded for the clay soils. d. Plot the variations of undisturbed and remolded shear strengths with the activity, A, and explain the observed behavior.
How is the plasticity index of a soil determined?