Question

A 500 g sample of dry soil was used for a combined sieve and hydrometer analysis (152 H type hydrometer). The soil mass passing through the 75u sieve is 120 g. Hydrometer analysis was carried out on a mass of 40 g that passed through the 75u sieve. The average temperature recorded during the test was 30°C. Given: Gs = 2.55, Cm = 0.50, Co= 2.5, u = 8.15x10-3 poises. The actual hydrometer reading Ra is 15 after a lapse of 120 min after the start of the test. Determine the 5.1) particle size D, 5.2) percent finer P'%) and 5.3) P(%).

Answer 1

To determine the particle size, percent finer, and percent passing of a soil sample based on the given data, specific gravity, and hydrometer reading.

Step-by-step explanation:

In this question, we are given the mass of a dry soil sample (500 g), the mass of soil passing through a 75u sieve (120 g), and the mass of soil used for the hydrometer analysis (40 g). We are also given the hydrometer reading (Ra = 15) after 120 minutes and other relevant parameters such as Gs, Cm, Co, and u. To determine the particle size (D), we can use the formula D = R/(GtCmCo), where R is the hydrometer reading after a lapse of time, Gt is the temperature correction factor, and Cm, Co are the specific gravity calibration factors. By substituting the given values into the formula, we can calculate the particle size.

To determine the percent finer (P'%) and percent passing (P%), we can use the equations P'% = (100 - Ra) * (1 - (Gs/Gt)) and P% = 100 - P'%. By substituting the given values into the equations, we can calculate the percent finer and percent passing.