# Geotech Practice Problems

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### #1 PE_2009

PE_2009

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• Discipline:Civil

Posted 04 October 2010 - 03:45 PM

1. A cylindrical specimen of moist clay has a diameter of 38 mm, height of 76 mm and mass of 174.2 grams. After drying in the oven at 105oC for about 24 hours, the mass is reduced to 148.4 grams. Find the dry density, bulk density and water content of the clay.
Assuming the specific gravity of the soil grains as 2.71, find the degree of saturation.

Answer : 82%

2. Soil excavated from a borrow is being used to build an embankment. The void ratio of the soil at the borrow is 1.14 and the porosity of the compacted soil in the embankment is 40%. If the volume of excavation is 200,000 m3, how many cubic metres of embankment can be built using this soil?

Answer : 155,763 cubic meter

3. 75 mm (internal diameter) thin walled sampling tube is pushed into the wall of an excavation and a 200 mm long undisturbed specimen, weighing 1740.6 g, was obtained. When dried in the oven, the specimen weighed 1421.2 g. Assuming that the specific gravity of the soil grains is 2.70, find the void ratio, water content, degree of saturation, bulk density and dry density.

(Ans. 0.679, 22.5%, 89.5%, 1.970 g/cm3, 1.608 g/cm3)

4. A one metre thick fill was compacted by a vibrating roller, and there was 30 mm reduction in the fill thickness. The initial void ratio was 0.94. What would be the void ratio after compaction?

(Ans. 0.883)

5. A 75 mm diameter and 20 mm thick cylindrical saturated clay specimen has a mass of 164.1 g. When dried in the oven at 105oC, the mass is reduced to 121.3 g. What is the specific gravity of the soil grains?

(Ans. 2.66)

6. Soil for a compacted earth fill is available from three different borrow sites. At the earth fill, the soil is to be compacted to a void ratio of 0.62 with a finished volume of 150,000 m3. The in situ void ratios and the costs (soil and transportation) per cubic metre for the three sites are given below. Which site would be economical?

Borrow Void ratio Cost/m3

X 0.85 \$7.80

Y 1.1 \$7.50

Z 1.4 \$6.60

(Ans. Borrow A)

7. A subbase for an airport runway, 100 m wide, 2000 m long and 500 mm thick, is to be constructed out of a clayey sand excavated from a nearby borrow, where the in situ water content is 6%. This soil is being transported in trucks having a capacity of 8 m3, where each load weighs 13.2 tonnes. In the subbase course, the soil will be placed at a water content of 14.2% to a dry density of 1.89 t/m3.
(a) How many truck loads will be required to complete the job?
( How many litres of water should be added to each truck load?
© If the subbase becomes saturated later, without any change in volume, what would be the water content? Assume Gs = 2.7.

(Ans. 15181, 1.03x106 litres, 17.3%)

### #2 PE_2009

PE_2009

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• Location:NJ
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Posted 23 October 2010 - 12:18 AM

QUOTE (PE_2009 @ Oct 4 2010, 11:45 AM) <{POST_SNAPBACK}>
1. A cylindrical specimen of moist clay has a diameter of 38 mm, height of 76 mm and mass of 174.2 grams. After drying in the oven at 105oC for about 24 hours, the mass is reduced to 148.4 grams. Find the dry density, bulk density and water content of the clay.
Assuming the specific gravity of the soil grains as 2.71, find the degree of saturation.

Answer : 82%

2. Soil excavated from a borrow is being used to build an embankment. The void ratio of the soil at the borrow is 1.14 and the porosity of the compacted soil in the embankment is 40%. If the volume of excavation is 200,000 m3, how many cubic metres of embankment can be built using this soil?

Answer : 155,763 cubic meter

3. 75 mm (internal diameter) thin walled sampling tube is pushed into the wall of an excavation and a 200 mm long undisturbed specimen, weighing 1740.6 g, was obtained. When dried in the oven, the specimen weighed 1421.2 g. Assuming that the specific gravity of the soil grains is 2.70, find the void ratio, water content, degree of saturation, bulk density and dry density.

(Ans. 0.679, 22.5%, 89.5%, 1.970 g/cm3, 1.608 g/cm3)

4. A one metre thick fill was compacted by a vibrating roller, and there was 30 mm reduction in the fill thickness. The initial void ratio was 0.94. What would be the void ratio after compaction?

(Ans. 0.883)

5. A 75 mm diameter and 20 mm thick cylindrical saturated clay specimen has a mass of 164.1 g. When dried in the oven at 105oC, the mass is reduced to 121.3 g. What is the specific gravity of the soil grains?

(Ans. 2.66)

6. Soil for a compacted earth fill is available from three different borrow sites. At the earth fill, the soil is to be compacted to a void ratio of 0.62 with a finished volume of 150,000 m3. The in situ void ratios and the costs (soil and transportation) per cubic metre for the three sites are given below. Which site would be economical?

Borrow Void ratio Cost/m3

X 0.85 \$7.80

Y 1.1 \$7.50

Z 1.4 \$6.60

(Ans. Borrow A)

7. A subbase for an airport runway, 100 m wide, 2000 m long and 500 mm thick, is to be constructed out of a clayey sand excavated from a nearby borrow, where the in situ water content is 6%. This soil is being transported in trucks having a capacity of 8 m3, where each load weighs 13.2 tonnes. In the subbase course, the soil will be placed at a water content of 14.2% to a dry density of 1.89 t/m3.
(a) How many truck loads will be required to complete the job?
( How many litres of water should be added to each truck load?
© If the subbase becomes saturated later, without any change in volume, what would be the water content? Assume Gs = 2.7.

(Ans. 15181, 1.03x106 litres, 17.3%)

Hardly 4 days left.
How is everybody doing?

### #3 boo

boo

Project Manager

• Senior Member
• 122 posts
• Discipline:Civil

Posted 23 October 2010 - 04:53 PM

QUOTE (PE_2009 @ Oct 22 2010, 06:18 PM) <{POST_SNAPBACK}>
QUOTE (PE_2009 @ Oct 4 2010, 11:45 AM) <{POST_SNAPBACK}>
1. A cylindrical specimen of moist clay has a diameter of 38 mm, height of 76 mm and mass of 174.2 grams. After drying in the oven at 105oC for about 24 hours, the mass is reduced to 148.4 grams. Find the dry density, bulk density and water content of the clay.
Assuming the specific gravity of the soil grains as 2.71, find the degree of saturation.

Answer : 82%

2. Soil excavated from a borrow is being used to build an embankment. The void ratio of the soil at the borrow is 1.14 and the porosity of the compacted soil in the embankment is 40%. If the volume of excavation is 200,000 m3, how many cubic metres of embankment can be built using this soil?

Answer : 155,763 cubic meter

3. 75 mm (internal diameter) thin walled sampling tube is pushed into the wall of an excavation and a 200 mm long undisturbed specimen, weighing 1740.6 g, was obtained. When dried in the oven, the specimen weighed 1421.2 g. Assuming that the specific gravity of the soil grains is 2.70, find the void ratio, water content, degree of saturation, bulk density and dry density.

(Ans. 0.679, 22.5%, 89.5%, 1.970 g/cm3, 1.608 g/cm3)

4. A one metre thick fill was compacted by a vibrating roller, and there was 30 mm reduction in the fill thickness. The initial void ratio was 0.94. What would be the void ratio after compaction?

(Ans. 0.883)

5. A 75 mm diameter and 20 mm thick cylindrical saturated clay specimen has a mass of 164.1 g. When dried in the oven at 105oC, the mass is reduced to 121.3 g. What is the specific gravity of the soil grains?

(Ans. 2.66)

6. Soil for a compacted earth fill is available from three different borrow sites. At the earth fill, the soil is to be compacted to a void ratio of 0.62 with a finished volume of 150,000 m3. The in situ void ratios and the costs (soil and transportation) per cubic metre for the three sites are given below. Which site would be economical?

Borrow Void ratio Cost/m3

X 0.85 \$7.80

Y 1.1 \$7.50

Z 1.4 \$6.60

(Ans. Borrow A)

7. A subbase for an airport runway, 100 m wide, 2000 m long and 500 mm thick, is to be constructed out of a clayey sand excavated from a nearby borrow, where the in situ water content is 6%. This soil is being transported in trucks having a capacity of 8 m3, where each load weighs 13.2 tonnes. In the subbase course, the soil will be placed at a water content of 14.2% to a dry density of 1.89 t/m3.
(a) How many truck loads will be required to complete the job?
( How many litres of water should be added to each truck load?
© If the subbase becomes saturated later, without any change in volume, what would be the water content? Assume Gs = 2.7.

(Ans. 15181, 1.03x106 litres, 17.3%)

Hardly 4 days left.
How is everybody doing?

today i start rewive the all-in-one

sun 6 min. water and struc.

mon 6 min struc and transport.

tue transpo and construc

wed and thu 6 min geo

### #4 PE_2009

PE_2009

Intern

• Senior Member
• 45 posts
• Gender:Male
• Location:NJ
• Discipline:Civil

Posted 23 October 2010 - 05:41 PM

QUOTE (boo @ Oct 23 2010, 12:53 PM) <{POST_SNAPBACK}>
QUOTE (PE_2009 @ Oct 22 2010, 06:18 PM) <{POST_SNAPBACK}>
QUOTE (PE_2009 @ Oct 4 2010, 11:45 AM) <{POST_SNAPBACK}>
1. A cylindrical specimen of moist clay has a diameter of 38 mm, height of 76 mm and mass of 174.2 grams. After drying in the oven at 105oC for about 24 hours, the mass is reduced to 148.4 grams. Find the dry density, bulk density and water content of the clay.
Assuming the specific gravity of the soil grains as 2.71, find the degree of saturation.

Answer : 82%

2. Soil excavated from a borrow is being used to build an embankment. The void ratio of the soil at the borrow is 1.14 and the porosity of the compacted soil in the embankment is 40%. If the volume of excavation is 200,000 m3, how many cubic metres of embankment can be built using this soil?

Answer : 155,763 cubic meter

3. 75 mm (internal diameter) thin walled sampling tube is pushed into the wall of an excavation and a 200 mm long undisturbed specimen, weighing 1740.6 g, was obtained. When dried in the oven, the specimen weighed 1421.2 g. Assuming that the specific gravity of the soil grains is 2.70, find the void ratio, water content, degree of saturation, bulk density and dry density.

(Ans. 0.679, 22.5%, 89.5%, 1.970 g/cm3, 1.608 g/cm3)

4. A one metre thick fill was compacted by a vibrating roller, and there was 30 mm reduction in the fill thickness. The initial void ratio was 0.94. What would be the void ratio after compaction?

(Ans. 0.883)

5. A 75 mm diameter and 20 mm thick cylindrical saturated clay specimen has a mass of 164.1 g. When dried in the oven at 105oC, the mass is reduced to 121.3 g. What is the specific gravity of the soil grains?

(Ans. 2.66)

6. Soil for a compacted earth fill is available from three different borrow sites. At the earth fill, the soil is to be compacted to a void ratio of 0.62 with a finished volume of 150,000 m3. The in situ void ratios and the costs (soil and transportation) per cubic metre for the three sites are given below. Which site would be economical?

Borrow Void ratio Cost/m3

X 0.85 \$7.80

Y 1.1 \$7.50

Z 1.4 \$6.60

(Ans. Borrow A)

7. A subbase for an airport runway, 100 m wide, 2000 m long and 500 mm thick, is to be constructed out of a clayey sand excavated from a nearby borrow, where the in situ water content is 6%. This soil is being transported in trucks having a capacity of 8 m3, where each load weighs 13.2 tonnes. In the subbase course, the soil will be placed at a water content of 14.2% to a dry density of 1.89 t/m3.
(a) How many truck loads will be required to complete the job?
( How many litres of water should be added to each truck load?
© If the subbase becomes saturated later, without any change in volume, what would be the water content? Assume Gs = 2.7.

(Ans. 15181, 1.03x106 litres, 17.3%)

Hardly 4 days left.
How is everybody doing?

today i start rewive the all-in-one

sun 6 min. water and struc.

mon 6 min struc and transport.

tue transpo and construc

wed and thu 6 min geo

Don't get confused with All in one book. I had bad experience. CERM is the best for morning session.

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