Tukikaivoja

Tukikaivoja, often translated as "support wells" or "caisson wells," are specialized excavation structures used in civil engineering and construction. They are particularly employed in situations where it is necessary to excavate deep shafts or foundations in challenging ground conditions, such as water-bearing soil, soft clay, or unstable sand. The primary function of a tukikaivo is to provide a stable, watertight, and structurally sound excavation pit that allows for the safe construction of underground elements like bridge piers, tunnels, or deep basements.

The construction of a tukikaivo typically involves excavating the ground within a large, cylindrical or rectangular caisson, which is a prefabricated, watertight structure. As excavation progresses, the caisson is sunk into the ground, either by its own weight or through the application of external forces. This process continues until the caisson reaches the desired depth, often resting on a stable bearing stratum. In water-bearing conditions, dewatering techniques may be employed within the caisson to maintain a dry working environment. Once in position, the caisson itself becomes an integral part of the final structure, serving as permanent formwork and a structural element. Specialized equipment, such as grab excavators and slurry pumps, are often used in the excavation process. The use of tukikaivoja is common in bridge construction, especially for foundations in rivers or lakes, as well as for the construction of underground railway stations and other large-scale infrastructure projects where traditional open excavation methods are impractical or unsafe.