Patent Application
20070274786
A pair of piles, inner pile 12, also referred to as tension pile 12, and outer pile 14, also referred to as compression pile 14, are substantially flat, sheet-type piles. Piles 12 and 14 are placed, preferably by driving, into natural ground 16 at the bank of water body 18 (shown as a canal) or, alternatively, into a levee at the bank of a water body. Piles 12 and 14 are preferably made of sheet steel, but they can also be made of wood, plastic, concrete, or a polymer. Pairs of piles 12 and 14 are oriented with broad, sheet faces parallel to each other and are positioned transversely, that is they are separated by approximately three feet to approximately twenty feet.
Piles 12 and 14 are rigidly connected together by connector 20, preferably a reinforced concrete cap. Alternatively, a strut, either a steel beam or a steel pipe or tube can be used to connect piles 12 and 14 together. Connector 20 preferably has an upper surface that is adapted for use as a roadway, a bicycle path, a pedestrian pathway, or the like. The rigidly connected pile pair develops a force couple that places inner pile 12 in tension and outer pile 14 in compression when an external force is applied to the outer face of inner pile 12. The force couple utilizes the cohesion of the soil to the piles to increase the resistance of the rigidly connected pile pair to transverse movement due to a horizontal force applied perpendicularly to the outer face of inner pile 12.
In one embodiment of a floodwall according to the invention, fill material 22, preferably sand or limestone gravel, is placed in the space between piles 12 and 14 in the pair, the fill material being selected to strengthen the pair of piles to help absorb and redistribute the force of any impact from a rapid surge as well as to resist transverse movement when a horizontal force is applied perpendicularly to the outer face of the inner pile. The fill material can be any granular or otherwise compactable material, including rock gravel or concrete gravel.
Riprap 24 can be placed at the bottom of a waterway adjacent to an outside face of inner pile 12 of the pair to protect against scour of the water bottom from tidal movement and/or from pumping operations. Earthen support 26, such as earth fill, can be placed adjacent to an outside face of one of the piles in the pair, for strengthening the pair of piles to resist transverse movement of the piles in the pair. Erosion control matting 28 can be placed over earthen support 26.
The method of protecting against flooding due to rising water according to the invention includes driving or placing a pair of piles into soil at or near an edge of an area to be protected from rising water and water-borne debris so that a portion of the pair of piles extends above the surface of the soil to a height at least equal to the maximum anticipated height of the water. Inner pile 12 is, as a rule of thumb, inserted into the ground 16 or into a levee to a depth of approximately two-thirds of the length of inner pile 12, and deeper if the water body has a bottom slope. Outer pile 14 is, as a rule of thumb, placed into ground 16 to approximately one-half of the depth of inner pile 12. The preference is for the water-side pile to be driven or inserted to a greater depth than the land-side pile, but the relative depth of the piles could be reversed if necessary or desired. It will be apparent to a person of ordinary skill that calculations based on specific soil data can change the total length needed for the piles and can alter the depths of penetration of the piles, as well as the relative depth of penetration as between pairs of piles. In any event one of the piles, preferably the inner pile, must extend below the sheer plane of the levee or soil in which the pile is placed.
The piles in the pair are connected together, preferably near or at the top of the piles, to develop, when an external force is applied to an outer face of the inner pile, a force couple that places one of the piles in tension and the other pile in compression, thereby using the cohesion of the soil to reduce transverse movement over what would occur with a single-layer pile for the same applied force. Some horizontal passive resistance to transverse movement can be anticipated.
Preferably, multiple pairs of piles are longitudinally abutted, overlapped, welded, bolted, or interlocked to form a continuous floodwall.
The disclosed embodiments of the apparatus, system, and method according to the invention are illustrative of the scope of the invention, which is recited in the appended claims. Various modifications of the disclosed embodiments can be made or are apparent from the description contained herein, without departing from the scope of the invention as claimed.
