Breakwater

Abstract

A breakwater, in which the surface thereof facing the sea (H) is a curved surface rendering the cross section of the breakwater a trapezoid with curved side (ABCDEFG) which comprises a shorter top side (EF), a longer bottom side (AG), and a curved side (ABCDE) facing the sea (H). The curve profile is similar to a recumbent concaved-up parabola.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a tsunami breakwater capable of effectively withstanding the attack of tsunami, storm surge or ocean waves.DESCRIPTION OF THE RELATED ART[0002]Recently, reports on catastrophes caused by the attack of tsunami or storm surge are impressive. For example, causes for tsunami, especially, the catastrophes caused by the Chilean Tsunami and the Indonesian Tsunami are particularly described in detail and vividly in “Climate Change and Natural Disaster” (edited by HUANG Jianmin and XU Zhihua, December 2005, Meteorological Press, Beijing).[0003]Causes of tsunami generally come from the seabed, such as a seabed earthquake, a volcanic eruption or seabed strata movement, and a tsunami may be also caused if meteorites fall into the sea. A tsunami occurs on average once per year, resulting in tremendous losses to human beings.[0004]The tsunami is almost consistent in terms of its current velocity from the sea level to the sea floor. When...

AI Technical Summary

Benefits of technology

[0028]An object of the invention is to provide a breakwater capable of effectively withstand the attack of tsunami, so that at the time when a tsunami arrives suddenly, towns, streets, ports and so on close to the seashore can be protected from catastrophes resulted from the tsunami. The present invention also provides a method for protecting a bay by using the tsunami breakwater to protect vessels anchored within the bay from the attack of tsunami.

[0029]In order to achieve above objects, the tsunami breakwater of the invention has a special shape. The surface of the breakwater facing the sea is a curved surface. When viewed from its cross section, the breakwater exhibits a curved side trapezoid with a shorter top side, a longer bottom side, and a side facing the sea and in the form of a curve. The position of the curved side trapezoid close to the seashore is the lowest point. The neighborhood of the lowest point is relatively flat. As the curve bends upward gradually from the lowest point to a position close to the breakwater, a bending radius thereof is decreased by degrees and a center of curvature thereof is also lowered by degrees. The center of curvature at a position close to the top surface of the breakwater has been lowered below the height of the breakwater. The curve from here on extends to the top surface of the breakwater in the form of a vertical line, or a straight line or a curve slightly inclined outwards. The profile of the curved side of the curved side trapezoid is similar to a recumbent concaved-up parabola, representing that the surface of the tsunami breakwater facing the sea is in the form of a paraboloid shaped surface. The breakwater has a suitable height, an appropriate wide, a proper sectional profile and reasonable construction intensity. The top surface of the breakwater can be used as a road, a footpath or a sightseeing stand. In addition, on the top and rear surfaces of the breakwater, trees, flowers and grasses can be planted so as to provide a garden, such that the breakwater can become both a breakwater which can effectively withstand the attack of tsunami and a pleasing, magnificent and beautiful landscape in coastwise cities.

[0030]The method for protecting a bay by using the tsunami breakwater of the invention is that constructing the tsunami breakwater at an entrance of the bay according to the applicable terrain or the shape of the seashore, wherein the breakwater is built by the sea and extends into the seawater at the entrance of the bay, and the sea area at the entrance of the bay is not completely closed by the breakwater such that a section of the sea area is left free of connections and serves as a channel for navigation of vessels. The bay built in this way is not only convenient for vessels to navigate into or out of the bay, but also greatly weakens an impact force caused by the surges at the time when the tsunami arrived due to a reduced channel area through which the ocean waves can get into or out of the bay by the tsunami breakwater, thereby protecting the vessels within the bay from the attack of tsunami.

[0031]Thanks to the curved surface with a profile of a parabola provided on the surface of the tsunami breakwater facing the sea, at the time of a tsunami, ocean waves rush to the seashore with a tremendous force, and the front end thereof first contacts the lowest position of the curved surface close to the seashore and then makes a gradual upward bending movement along the profile of the curved surface. Meanwhile, the tremendous impact force of the ocean waves is transferred to the foundation of the breakwater in a normal direction of the curved surface. The foundation then transfers a reaction force through the curved surface back to ocean waves after receiving the tremendous impact force, thereby keeping the ocean waves moving in a tangential direction of the curved surface. The ocean waves, initially rushing horizontally to the seashore, finally rush to the sky in the tangential direction of the curved surface since the reaction force from the curved surface of the breakwater gradually changes the moving direction of the ocean waves. The seawater falling back after vertically rushing to the sky also functions to prohibit the impact of the ocean waves.

[0033]First, at the time when the surges resulted from the tsunami directly rush to the breakwater, the curved surface of the breakwater gradually weakens the tremendous force of the surges, thereby changing a fashion in which the ocean waves lash at the bank from an instantaneous impact to a gradual impact, thus, the impact force of the ocean waves is reduced greatly, correspondingly, the capacity of the breakwater of withstanding the ocean waves is improved due to a balanced stress thereon.

[0034]Second, the ocean waves rushing rapidly to the seashore rush to the sky vertically along the profile of the curved surface, and then fall back into the sea, since the reaction force provided by the curved surface of the breakwater changes the moving direction of the ocean waves gradually. Thus, tremendous catastrophes caused by the ocean waves passing across the breakwater are avoided in which buildings are swept away by the seawater and lands are flooded.

Problems solved by technology

The bay built in this way is not only convenient for vessels to navigate into or out of the bay, but also greatly weakens an impact force caused by the surges at the time when the tsunami arrived due to a reduced channel area through which the ocean waves can get into or out of the bay by the tsunami breakwater, thereby protecting the vessels within the bay from the attack of tsunami.

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