What does a caisson provide during excavation?

A caisson, when used during excavation, primarily provides lateral support. It is a large, often cylindrical, structure that is sunk into the ground to create a stable base for deep foundations. The sides of the caisson act to resist lateral earth pressures that can occur due to the surrounding soil, especially in unstable or saturated conditions. This is crucial during excavation because it helps prevent soil collapse and maintains the integrity of the excavation site.

While deep foundation support is a key function of caissons once they are installed, during the excavation phase, their role is to provide lateral support to the walls of the excavation. The design of caissons allows them to handle heavy loads while providing a safe working environment by keeping the excavation site stable.