Constructing underground circular storage tank - made of concrete panels without reinforcement but using spaced deformable screen inside structure during excavation

摘要

Flat, unreinforced concrete panels are used to form the vertical wall of an underground tank having a roughly circular cross-section. Before the tank is excavated a deformable screen with an approx. circular cross-section is installed at a short distance inwards from the wall panels, and sunk to a depth below ground level which is approx. equal to the depth of the wall panels. The screen is given a starting thickness of about 10cm. and is for pref. positioned at about 50cm from the wall panels. The thickness given to the wall panels is abt. 1m. The screen is formed from a suspension of bentonite. The wall panels are formed in the ground and run down to a natural or artificial layer which excludes water.