Concept explainers
(a)
Mention whether the given statement is true or false.
(a)
Answer to Problem 3.1P
The given statement, “Moisture content must be always less than 100%” is
Explanation of Solution
Calculation:
The moisture content (w) is the ratio of weight of water
If the water content in the soil exceeds 100%, the weight of water
Hence, the moisture content may be greater than 100%.
Therefore, the given statement, “Moisture content must be always less than 100%” is
(b)
Mention whether the given statement is true or false.
(b)
Answer to Problem 3.1P
The given statement, “Plastic limit is always less than plasticity index” is
Explanation of Solution
Calculation:
Write the equation for the relationship between the plasticity index (PI), liquid limit (LL), and the plastic limit (PL) as follows:
When the plastic limit is equal or greater than the liquid limit, the plasticity index is considered as zero. In this case the plastic limit is greater than the plasticity index.
The given statement is not satisfying the condition.
Therefore, the given statement “Plastic limit is always less than plasticity index” is
(c)
Mention whether the given statement is true or false.
(c)
Answer to Problem 3.1P
The given statement, “Liquidity index cannot be negative” is
Explanation of Solution
Calculation:
Write the equation for liquidity index (LI) as follows:
Here, the in situ moisture content of the soil is w, plastic limit is PL, and liquid limit is LL.
For sensitive clays, the in situ moisture content is greater than the liquid limit
In this condition liquidity index is greater than 1
For soils that are heavily over consolidated, the in situ moisture content is less than the plastic limit
The liquidity index can be less than zero.
Therefore, the given statement “Liquidity index cannot be negative” is
(d)
Mention whether the given statement is true or false.
(d)
Answer to Problem 3.1P
The given statement, “The dry unit weight is always less than the moist unit weight” is
Explanation of Solution
Calculation:
Find the moist unit weight
Find the dry unit weight
From the equations of moist unit weight and the dry unit weight, the dry unit weight will be less than the moist unit weight.
Therefore, the given statement “The dry unit weight is always less than the moist unit weight” is
(e)
Mention whether the given statement is true or false.
(e)
Answer to Problem 3.1P
The given statement, “Relative density increases with void ratio” is
Explanation of Solution
Calculation:
Write the equation for relative density
Here, in situ void ratio of the soil is e, void ratio of the soil in the loosest condition is
Refer to the relative density equation, the relative density is inversely proportional to the void ratio.
When the void ratio increases, the relative density decreases.
Therefore, the given statement “Relative density increases with void ratio” is
Want to see more full solutions like this?
Chapter 3 Solutions
Fundamentals of Geotechnical Engineering (MindTap Course List)
- Water depth in a lake is 3 m. A soil sample was collected from the sediment in the lake and the following properties are obtained.Calculate the following pressures at a depth of 12 m below the bed levelof the lake (assume the entire top clay layer is saturated):(A) The total pressure(B) The pore pressure(C) The intergranular pressurearrow_forwardA moist soil has a volume of 0.0081 m³ and weighs 151.2 N. The oven dry weight of soil is 138.6 N. Assume Gs = 2.7 and find the following in requested units: a. water content, w (%) b. total unit weight, y (kN/m²) c. dry unit weight, yd(kN/m²) d. void ratio, earrow_forwardDetermine the value of void ratio if porosity 0.79arrow_forward
- A sand has Gs = 2.66. Calculate the hydraulic gradient that will cause boiling for e = 0.35, 0.45, 0.55, 0.7, and 0.8.arrow_forwardFor a normally consolidated soil, the following is given: Determine the following: a. The compression index, Cc. b. The void ratio corresponding to pressure of 200 kN/m2arrow_forwardDetermine void ratio if porosity 0.39arrow_forward
- Principles of Geotechnical Engineering (MindTap C...Civil EngineeringISBN:9781305970939Author:Braja M. Das, Khaled SobhanPublisher:Cengage LearningPrinciples of Foundation Engineering (MindTap Cou...Civil EngineeringISBN:9781305081550Author:Braja M. DasPublisher:Cengage LearningFundamentals of Geotechnical Engineering (MindTap...Civil EngineeringISBN:9781305635180Author:Braja M. Das, Nagaratnam SivakuganPublisher:Cengage Learning