What does the layering of materials in an embankment help improve?

Layering materials in an embankment contributes to multiple important engineering properties, which is why the correct answer encompasses all of the listed improvements: stability, drainage, and load-bearing capacity.

When materials are layered, it allows for better distribution of stress throughout the embankment. This practice enhances stability by ensuring that the weight and forces acting on the embankment are evenly spread, reducing the risk of failure or sliding. Each layer can be compacted to specific densities, which further strengthens the overall structure.

Additionally, the layering can facilitate improved drainage. Properly designed layers can provide pathways for water to flow through or drain away, preventing the buildup of pore water pressure that could weaken the embankment. This is particularly important in areas where water saturation could lead to increased instability.

Furthermore, layering affects load-bearing capacity by allowing the structure to support heavier loads without failing. Different materials can be selected for each layer based on their physical properties, optimizing the overall performance of the embankment under varying load conditions.

In summary, the technique of layering materials in an embankment plays a crucial role in enhancing stability, drainage, and load-bearing capacity, making it essential for effective engineering design in excavating, grading, and surfacing practices.