Effective stress acting within a soil mass_____________?
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Answer: C. decreases both voids ratio and permeability
Explanation
An increase in effective stress compresses the soil skeleton, decreasing both void ratio and permeability. Tighter packing of soil particles reduces the size and continuity of interconnected pore channels. Reduced pore space restricts fluid flow, leading directly to lower hydraulic conductivity in the soil. Effective stress is the inter-granular pressure transmitted through direct solid particle contacts. Void ratio measures the volume of pore spaces relative to the volume of solid soil particles. Permeability depends heavily on the geometry and size of pore passages within the soil matrix.
Deep foundation loading increases effective stress in underlying clay layers, reducing their permeability. Groundwater flow modeling must account for decreasing permeability as consolidation progresses over time. Understanding stress-permeability relationships is vital for analyzing consolidation settlement rates. Option A suggests void ratio increases, which contradicts the basic mechanics of soil compression under load. Option B suggests both increase, ignoring the fact that compression reduces pore space and flow capacity. Option D suggests void ratio decreases while permeability increases, which violates fluid flow principles.
- Subject
- Engineering
- Category
- Civil Engineering
- Topic
- —
- Difficulty
- medium
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