| 摘要 |
<p>PURPOSE:To obtain a water purifying bank preventing stagnation with an uniform purifying zone, by setting the permeability coefficient of the bank body material smaller at the nearby zone of the central part of the axial line and larger at the nearby position of both ends. CONSTITUTION:In a water purifying bank 20, a bank body material having a larger permeability coefficient, a bank body material 21 having a larger diameter for instance, is arranged at both sides and a bank body material 22 having a smaller diameter is arranged at the central part. And these are piled up to form a nearly trapezoidal shape from the bottom of the sea and coated with covering stones 4. The seawater passing through the clearances among the bank body material flows slowly at the central zone and faster at both ends. The inflow distribution of the seawater into the inside zone shows a curve indicated in fig. 31 when only the diameter of bank body material is taken into consideration. The seawater does not transfer in the land 11, the speed distribution of the seawater is as shows in the curve 32 when the diameter of the bank body material is uniform. The inflow speed of the seawater flowing through the bank 20 is as shown in the combined line and the inside zone is purified in a uniform flow distribution.</p> |
