ANJUMAN COLLEGE OF ENGINEERING & TECHNOLOGY MANGALWARI BAZAAR ROAD, SADAR, NAGPUR DEPARTMENT OF CIVIL ENGINEERING.

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1 Tutorial Sheet 1 (UNIT 1) 1. Introduction: Formation of soil, residual & transported soil, major deposits found in India, soils generally used in practice such as sand, gravel, organic soil, clay, Betonites, black cotton soil etc. Introduction to clay mineralogy. 2. Phases of soil: Various soil weight & volume inter-relationship. Density index, methods of determining in situ density.

2 1] A cohesive soil specimen was subjected to laboratory tests to obtain the following data: The moisture content w = 22.5 percent; G s = To determine the approximate unit weight, a sample weighing g was placed in a 500-cm 3 container with 382 cm 3 of water required to fill the container. The reader should note the use of standard laboratory units. Solution. Step 1. The wet unit weight is obtained from total sample weight as:- Step 2. The dry unit weight is obtained by:- Step 3. The void ratio e and porosity n require some volume computations as follows:- Step 4. To find the degree of saturation S it will be necessary to find the volume of water in the voids. The weight of water Ww is the difference between the dry and wet weights; therefore, for G w obtain V w = W w when using g and cm 3 ; therefore, Step 5. The dry bulk specific gravity is obtained as (dimensionless):-

3 2] If a soil sample has a dry unit weight of 19.5 KN/m3, moisture content of 8% and a specific gravity of solids particles is Calculate the following: a) The void ratio. b) Moisture and saturated unit weight. c) The mass of water to be added to cubic meter of soil to reach 80% saturation. d) The volume of solids particles when the mass of water is 25 grams for saturation.

4 3] An earth dam require one hundred cubic meter of soil compacted with unit weight of 20.5 KN/m 3 and moisture content of 8%, choose two from the three borrow pits given in the table below, knowing that the first must be one of the two borrow pits, the specific gravity of solid particles is 2.7. Choose the most economical choice. Total required volume from borrow pit#1 =114.68m 3 The available volume from borrow pit #1= 80m 3 The rest required volume from borrow pit #1= = 34.68m 3 Now, we calculate the required volume from borrow pits 2&3 and calculate the cost of each volume and take the lowest cost soil.

5 4] A soil sample has avoid ratio of 0.72, moisture content = 12% and Gs = 2.72 determine the following: a) Dry unit weight, moist unit weight (KN/m 3 ). b) Weight of water in KN/m 3 to be added for 80% degree of saturation. c) Is it possible to reach a water content of 30% without change the present void ratio. d) Is it possible to compact the soil sample to a dry unit weight of 23.5 KN/m 3.

6 5] An undisturbed sample of clayey soil is found to have a wet weight of 285 N, a dry weight of 250 N, and a total volume of 14x103 cm 3 if the specific gravity of soil solids is 2.70, determine the water content, void ratio, and the degree of saturation. 6] A proposed earth dam requires 7500 m3 of compacted soil with relative density of 94%, maximum void ratio of 0.73, minimum void ratio of 0.4 and specific gravity (Gs )=2.67. Four borrow pits are available as described in the following table. Choose the best borrow pit with minimum cost.

7 7] The results of a standard compaction test for a soil having a value of ( =. ) are shown in the table below. Find: a) The optimum water content. b) The maximum dry unit weight. c) The void ratio (e). d) Degree of saturation (S). e) Moisture unit weight. f) Find the weight of water need to be added to 1m 3 to reach 100% degree of saturation. Firstly, we calculate the value of dry unit weight in the following table:-

8 8] A sample of saturated clay was placed in a container and weighed. The weight was 6N. The clay in its container was placed in an oven dray for C. The weight reduced to a constant weight of 5N. The weight of the container is 1N. If Gs = 2.7, determine: (a).water content. (b).void ratio. (c).moist unit weight. (d).dry unit weight. (e).effective unit weight (Submerged unit weight).

9 9] A dry sand is placed in a container having a volume of 0.3 ft 3. The dry weight of the sample is 31 Ib. Water is carefully added to the container so as not to disturb the condition of the sand. When the container is filled, the combined weight of soil plus water is 38.2 Ib. From these data, compute the void ratio of soil in the container, and the specific gravity of the soil particles. [Hint: water density = 62.4 Ib/ft 3 ]

10 10] The moist densiteis and degree of saturation of a soil sample are given in the following table: Determine the weight of water in Kg, that will be in 7 m 3 of the soil when it saturated.

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