When designing a group of friction piles in a soft clay, what critical failure mechanism, distinct from individual pile failure, must be assessed for the entire group?

When designing a group of friction piles in soft clay, the critical failure mechanism distinct from individual pile failure that must be assessed for the entire group is block failure, also known as group failure. This mechanism occurs when the entire block of soil encompassed by the pile group, including the piles themselves, behaves as a single, rigid unit and fails by pushing through the surrounding or underlying soil. Instead of each pile failing individually by losing its skin friction or end bearing capacity, the soil mass around and beneath the entire group fails in shear alo....