A Sample of soil was tested in the laboratory with the following results Liquid limit =30% Plastic limit =12% U.S. Sieve Size                  Percentage Passing 3/8 in.                                         100.0 No. 4                                           76.5 No. 10                                         60.0 No. 40                                         39.7 No. 200                                       15.2 Classify the soil sample by the USCS classification system.

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.

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%

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)

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 2.4 with the following data. 2.4 The following are the results of a sieve analysis. a. Determine the percent finer than each sieve and plot a grain-size distribution curve. b. Determine D10, D30, and D60 for each soil. c. Calculate the uniformity coefficient Cu. d. Calculate the coefficient of gradation Cc.

How is the plasticity index of a soil determined?

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.

Repeat Problem 2.11 with the following data. 2.11 The grain-size characteristics of a soil are given in the following table. 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 using the USDA system. d. Repeat Part b using the AASHTO system.

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.