Question

Select the incorrect statements about the flexible wall permeameter.

1. Principle stresses are controlled.
2. Sidewall leakage is avoided.
3. Chemical reaction may take place between membrane and liquid in soil samples.
4. All of above.

1. Select the correct statement about mechanisms responsible for stress cracking in geomembrane (GM).

1. Development of friction forces along the side slope.
2. Hydration process in liner system
3. Localized subsidence induced by poorly compacted solid waste
4. Generation of wrinkles due to poorly installation and thermal expansion.

Answer 1

Solution:

First question:

Answer: C. Chemical reaction may take place between membrane and liquid in soil samples.

In flexible wall permeameter, there is a flexible membrane which provides a better attachment of the soil sample with the wall and due to this, no gap is left between the soil sample and the wall and ultimately there is no side leakage. And in flexible wall permeameter, the stresses principal confining stresses can be controlled in order to test for the field ( site ) stress conditions.

Second question:

Answer: D. Generation of wrinkles due to poorly installation and thermal expansion.

The geo-membranes are not allowed for much expansion as they are designed for low thermal properties in order to ensure dimensional stability. But due to temperature variation ( increased temperature ) , thermal expansion takes place which causes wrinkles and cracks along the liner resulting in the failure of the geo-membrane.