Case Study 1: Wet Method for Embankment Support

A highway embankment is to be constructed over a deposit of soft, saturated marine clay with an undrained shear strength ($s_u$) of $25\text{ kPa}$. The engineer decides to install stone columns using the Wet Vibro-Replacement method to increase bearing capacity and accelerate consolidation.

Case Study 2: Dry Method for a Commercial Building Foundation

A single-story commercial building is planned on a site underlain by $8\text{ meters}$ of firm but compressible silty clay ($s_u = 45\text{ kPa}$). The water table is relatively low. The project has strict environmental constraints regarding slurry run-off.

Case Study 3: The Concept of Stress Concentration

Following the installation of stone columns beneath a large circular oil storage tank, settlement monitoring reveals that the total settlement of the tank is significantly less than what the original soft clay would have allowed.

Case Study 4: Radial Drainage and Accelerated Consolidation

In the same oil storage tank project (Case Study 3), piezometers installed in the soft clay between the stone columns show that the excess pore water pressure dissipates rapidly, much faster than predicted by 1-D vertical consolidation theory.

Case Study 5: Bulging Failure in Extremely Soft Clay

A contractor attempts to install stone columns in a deposit of highly sensitive, organic "peat-like" clay with an extremely low undrained shear strength ($s_u < 10\text{ kPa}$). Upon loading the test embankment, the foundation fails excessively, and the embankment sinks.

Case Study 6: Bearing Capacity (Punching) Failure

Stone columns are designed to support a square spread footing for a heavy column load. The columns are installed through $4\text{ meters}$ of soft clay but terminate within the clay layer, $2\text{ meters}$ above a dense gravel bearing stratum. During proof loading, the footing settles dramatically without significant bulging of the columns.