Introduction: Failure Mechanisms

Question 1

What are common soil failure mechanisms?

Answer 1

1. Heave – Upward movement due to groundwater uplift.
2. Squeezing – Soil pushed out due to high stress.
3. Sliding – Slope failure due to excessive water.
4. Piping – Underground erosion forming channels.
5. Erosion – Removal of soil by water, wind, or ice.
6. Bulking – Increase in soil volume due to disturbance.

Question 2

What is internal erosion?

Answer 2

The removal of soil particles due to seepage, leading to instability (e.g., sand boils).

Question 3

What is negative lateral friction or downdrag?

Answer 3

A force acting downward on piles due to soil settlement, reducing their effective load-bearing capacity.