Definition of a pile — choose the most general and correct statement describing how a pile transfers load to the ground.

Introduction / Context:
Piles are deep foundation elements used when shallow soils are weak or when loads must be transferred to deeper, stronger strata. A concise, correct definition should encompass both end bearing and skin friction mechanisms and should not restrict the material type unnecessarily.

Given Data / Assumptions:

• Piles may be timber, concrete, or steel; they are slender relative to their length.
• Load transfer occurs via tip (end bearing) and/or shaft (skin friction) to the surrounding ground.
• Ground conditions dictate the dominant mechanism.

Concept / Approach:

The most general definition highlights interaction with the surrounding soil. A pile transfers load to the ground through a combination of end bearing at its toe and friction along its shaft. Statements that say “only end” or “only friction” are incomplete; restricting piles to concrete also misses common materials such as steel H-piles and timber piles.

Step-by-Step Solution:

Verification / Alternative check (if short method exists):

Foundation textbooks define pile load transfer as a combination of shaft resistance and base resistance, aligning with option B.

Why Other Options Are Wrong:

Option A and C are partial mechanisms only; option D restricts material to concrete; option E is incorrect on both material and mechanism.

Common Pitfalls (misconceptions, mistakes):

Thinking all piles are concrete; assuming a single mechanism always dominates regardless of soil profile.

Final Answer:

A pile is a slender member which transfers its load to the surrounding soil.