What is the sensitivity of soil?
Soil sensitivity is defined as the ratio of peak to remoulded shear strength. Problem soil materials are those that show large strength losses on disruption, resulting in catastrophic failure, liquefaction and long run-out distances.
Can sensitivity of soil be less than 1?
Soils generally have a sensitivity value 1 or greater than 1. But if stiff soils have fissures or cracks it may sometimes exhibit a sensitivity value of less than 1, because these cracks present in an undisturbed soil may be removed upon remoulding. Hence their strength will increase after remoulding.
Which soil type has sensitivity less than 1?
Detailed Solution
| Classification | Sensitivity |
|---|---|
| Insensitive clay | < 1 |
| Slightly sensitive clay | 1-2 |
| Medium sensitive clay | 2-4 |
| Very sensitive clay | 4-8 |
What is index test of soil?
Soil index properties are properties which facilitate identification and classification of soils for engineering purposes. Plastic soils (clays) are normally described as cohesive as a distinction from non-plastic soils (sands and gravels) which are often called granular or non-cohesive.
How do you determine soil sensitivity?
A four bladed vane is inserted into the soil specimen, and the torque necessary to rotate the vane is measured and is related to the undrained shear strength. It is used on both undisturbed and remoulded soil samples to measure the soil sensitivity, i.e.
What is sensitivity of normal clay?
It is formed when the size of the particle is less than 0.0002 mm….Detailed Solution.
| Classification | Sensitivity |
|---|---|
| Slightly quick clay | 8-16 |
| Medium quick clay | 16-32 |
| Very quick clay | 32-64 |
| Extra quick clay | >64 |
What is sensitivity of clay?
The degree of sensitivity of a clay is defined as the ratio of (compressive strength undisturbed) to (compressive strength remoulded), remoulding being carried out in such a manner as to avoid any change in water content.
What is soil density index?
DEFINITIONS. Relative density or density index is the ratio of the difference between the void ratios of a cohesionless soil in its loosest state and existing natural state to the difference between its void ratio in the loosest and densest states.
What is index property test?
Tests to determine index properties that in turn serve to identify the soil type and indicate its consistency.
How do you find C and Phi of soil?
c’ and φ’ vary in terms of soil types. As both of this parameters denotes the effective condition but there is a simple method to estimate this. The strength of soil can be determined by Mohr coulumb equation. The formula is Ԏ = C + σ tanФ.
What do you mean by sensitivity and thixotropy of clay?
Explanation: Sensitivity is the degree of disturbance due to ‘remoulding’ and the thixotropy is the process of softening of clay due to ‘remoulding’, followed by time-dependent gain in strength. So, it can be said that they are directly proportional to each other.
How do you measure the sensitivity of clay?
The degree of sensitivity of a clay is defined as the ratio of (compressive strength undisturbed) to (compressive strength remoulded), remoulding being carried out in such a manner as to avoid any change in water content. Compressive strength is usually measured by the unconfined compression machine1.
What is the density index formula?
Explanation: The density index is defined as the difference between the voids ratio of the soil in its loosest state emax and its natural void ratio e to the difference between the voids ratio in the loosest and densest state. ID=\frac{(e_{max} – e)}{(e_{max}-e_{min})}.
What is the unit of density index?
Density Index / Relative Density / Degree of Density It is the Unit less. It is defined as ratio of difference of void ratio of soil in loosest state & natural state to the difference of void ratio of soil in loosest state & densest state. e = void ratio of soil in natural state.
What are index properties of soil Why are they important?
Index properties are the properties of soil that help in identification and classification of soil. These properties are generally determined in the laboratory. In situ density and relative density require undisturbed sample extraction while other quantities can be determined from disturbed soil sampling.
What is C value in soil?
Cohesion (c) This is almost zero for dry loose sandy soils and can rise to over 100 kN/m2 for hard dry clay soils. Friable (moist) sandy loam soils are typically in the range 5 to 15 kN/m2 and moist plastic clay soils 10 to 40 kN/m2.
What is sensitivity How are soils classified on sensitivity?
Soil sensitivity is defined as the ratio of the undrained shear strength of undisturbed soil to the undrained shear strength of remoulded soil at the same water content, i.e.
What is sensitivity and thixotropy of clay?
Thixotropy of clay is the process of strength loss and gain with no alteration in volume or water content. This can also be defined as “a softening process caused by remoulding, followed by a time-dependent return to the original harder state.”
What does Index property mean?
Index properties are the properties of soil that help in identification and classification of soil for general engineering purpose. These properties are generally determined in the laboratory. Disturbed samples or remoulded samples can be used to determine the index property of the soil.
What is soil sensitivity?
This behaviour is referred to as soil sensitivity, which is described as the ratio of shear strength in the undisturbed state to that in the completely remoulded state.
What is a highly sensitive clay soil?
sensitive clays. Different levels of soil sensitivity have been shown in different versions of CFEM and their errata. The current manual. CFEM (2006) classifies clay as highly sensitive if its sensitivity is greater than 40 (classified as Class F soil).
How sensitive is soil to marine environment?
1 Soil that has been deposited in a marine environment is usually very sensitive. 2 The sensitivity of some quick clays will exceed 100. 3 Soils that have been over-consolidated have been observed to be insensitive.
What are soil quality indicators?
Soil quality indicators are physical, chemical, and biological properties, processes, and characteristics that can be measured to monitor changes in the soil. The types of indicators that are the most useful depend on the function of soil for which soil quality is being evaluated.