Electro-osmosis is primarily used to
- ADetermine the permeability of soil
- BConsolidate fine-grained soils using an electric fieldCorrect
- CIncrease the shear strength of granular soils
- DPurify the ground water
Solution
Concept
Fine-grained soil consolidation using electro-osmosis
Formula
NONE
Step-by-step solution
1. Electro-osmosis involves applying a direct current electric field across low-permeability fine-grained soil (clay). 2. The electric field drives pore water towards the cathode, dewatering and consolidating the clay soil to increase its stability. 3. Thus, option B accurately describes the primary application of electro-osmosis in soil mechanics. Answer: B
Explanation
Electro-osmosis is a ground improvement technique where direct current is applied across fine-grained soils to drive pore water movement toward a cathode. This forced movement of water reduces soil water content, accelerating consolidation and increasing shear strength in low-permeability clays. Thus, option B correctly states the primary purpose of electro-osmosis.
Why the other options are wrong
A) Soil permeability is determined using falling head or constant head permeameter tests. C) Electro-osmosis is applied to fine-grained cohesive soils like clays rather than granular soils. D) Groundwater purification involves filtration and chemical treatment processes rather than electro-osmotic dewatering.
Shortcut
Electro-osmosis = Dewatering and consolidating fine-grained clay soils using an electric field.
Common mistake
Selecting option C by assuming electro-osmosis applies to granular soils rather than fine-grained soils with low permeability.
Correct answer: B) Consolidate fine-grained soils using an electric field