Bearing capacity is technically the vertical load that soil can support before it gives way resulting in catastrophic failure. The failure plan is an arc that extends from the foundation edge, below the foundation, and reaches the surface about 1 to 2 foundation widths away. However, most soils will exhibit excessive settlement before they reach failure. As such, failure in geotechnical engineering is governed almost exclusively by settlement. However, for ease of structural design, the allowable soil bearing capacity is generally given as the bearing load that the soil can withstand without experiencing more than 1 inch of settlement.
