Israel Eduardo Rendon Villalon
Study on watetight performance of wire brush by Element tests.
Mitsutaka Sugimoto
The pneumatic caisson method consists of a watertight retainer structure used for construction that allows the worker to be up to 70m underground. The water that applies pressure to the chamber is balanced with pressure within the chamber itself. This means that in order to go 70m underground the chamber has to have 0.7MPa of air pressure.
Whether it is a bridge pier, a concrete dam or even for the repair of ships, the pneumatic caisson method is the most suitable there is. Nevertheless, passing those 70m represents a big challenge, since the human body cannot resist more than 0.7MPa of pressure.
My job here was to try out different equipment combinations until I find one that could help the chamber to go deeper without increasing the pressure. I used three different types of equipment: ¡Èwire brushes¡É ¡Èclearance plates¡É and ¡Èsimulating bars¡É, each one with its own purpose. The wire brushes (which are always covered with grease) are found attached to the chamber, and slide against the excavation surface. The clearance plates represent the space found between the excavation surface and the chamber. The last piece of equipment is known as ¡Èsimulating bars¡É. These bars are made of steel and are attached to the plate resembling the irregularity of the excavation surface. With this experiment I could understand that:
1) Without the simulating bars the pressure applied to the grease can go up to 1.5Mpa. However, it is very difficult to find an excavation surface that is uniform and smooth.
2) The equipment that had the most effect on grease pressure were the simulating bars. The higher the simulating bars were, the lower the pressure was.
3) The smaller the clearance, the higher the grease pressure
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