Steenstorten: Voorspelling van het stort als gestort wordt vanuit een vast punt

Steenstorten: Voorspelling van het stort als gestort wordt vanuit een vast punt

Meermans, W.

Civil Engineering and Geosciences

Hydraulic Engineering

1997-01-14

In the construction of dams and in protection of civil engineering works in water courses often use is made of dumped stones. The dumping process can be divided in two stages. During the first stage the resulting mound of stones on the bottom of the water course is built up vertically. In the second stage the stones are under the angle of repose and increase of height of the mound can only be accomplished together with an increase in width of the basis. In the dumping process four sub-processes can be distinguished, i.e. the positioning of the dumping vessel, the start of the falling process, the falling process itself and jumping and rolling of the stones that hit the bottom. Three different partial processes can take place during the falling process. The first one is a (semi-) diffusion process, which results in a swinging motion of a singular stone. The mathematical description of this process is called the "Single Stone Model". On average the distance of the final position of the stones, measured from the projection on the bottom of the point where the fall is started is zero. The spreading ofthe stones is proportional to the square root ofthe water depth. A second possible partial process is caused by the Magnus effect. A constant horizontal force is executed on the vertically falling body. The third partial process can be caused by asymmetric flow separation. This also causes a horizontal force to act on the body. Drag causes the movement to be uniform. Last two mentioned processes result in a ring- shaped mound. The diameter of the ring is proportional to the water depth. The mathematical model of this process is called the "ring model". In practice all processes will take place. The mathematical descriptions can be combined in a combination model.

steenstorten
stone dumping
side stone dumper
bed protection

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© 1997 Meermans, W.