CN106836117B - Porous floating breakwater - Google Patents
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Abstract
The invention discloses a porous floating breakwater which comprises a plurality of breakwater units which are connected in sequence, wherein each breakwater unit comprises a first floating box, a second floating box, a connecting rod and two layers of vertical plates, the first floating box and the second floating box are rigidly connected through the connecting rod, the first floating box and the second floating box are connected with a mooring balancing weight through anchor chains for mooring, the two vertical plates are fixedly arranged on the connecting rod, a plurality of water through holes are formed in the two vertical plates, and the opening rate of the water through holes of the vertical plates is 9-11%. The porous floating breakwater has the advantages of good wave dissipation effect, small structural stress, good safety, simple structure, convenience in construction and wide application range, and has important practical significance for wave prevention of port engineering.
Description
Technical Field
The invention relates to a porous floating breakwater, and belongs to the field of breakwaters.
Background
The breakwater is an important harbor and coastal engineering building, is mainly used for defending invasion and attack of waves to harbor water areas, provides stable and safe berthing conditions and operation water areas for harbors, improves the design conditions of harbor hydraulic buildings and protects harbor hydraulic buildings. In addition, on sandy or muddy coasts, breakwaters also play a role in reducing or preventing silt from entering the port, and for ports with freezing, breakwaters also reduce the flow of ice out of the port from entering the port. The breakwater has a slope type, a vertical type, a hybrid type, a permeable type, a floating type and the like, wherein the first three types are the traditional bottom-sitting breakwater. Traditional bed formula breakwater can shield waters in the harbor better and service life is longer, however, bed formula breakwater has inevitable limitation: along with the increase of the engineering water depth and the deterioration of foundation conditions, the engineering cost is increased rapidly, and the construction difficulty is increased; the water circulation in the shield area is limited, and sediment deposition and water pollution in the harbor are easy to generate. Meanwhile, the pile foundation open type breakwater is poor in capability of adapting to the change of the tide level, and the shielding effect is difficult to control.
With the development of comprehensive needs of coastal environment protection, sightseeing and traveling, aquaculture and the like, the concept of development of coasts and ports is undergoing a great transformation. In order to adapt to the requirements of deep water, soft foundation, introduction of seawater exchange to improve the water environment in the harbor and low cost, the structural type of the harbor engineering develops to novel structural types such as a permeable structure, an energy dissipation structure, a multifunctional structure and the like.
In recent years, the floating breakwater has received close attention from ports, coasts and ocean engineering circles at home and abroad because it has the following advantages compared to the conventional bottom-set breakwater: (1) when the water depth is larger, the floating breakwater greatly reduces the engineering consumption, and the engineering cost is generally relatively low; (2) foundation treatment is not needed during construction, and the construction method is not limited by foundation conditions, so that the construction difficulty is reduced; (3) the water body exchange function is very strong, the seawater pollution can be prevented, the sediment movement and the fish migration are not influenced, and the aquatic environment of the sheltering zone is protected; (4) the construction quantity is small, the construction is simple and rapid, and the disassembly and the arrangement adjustment are easy; (5) the floating body can be lifted along with the change of the tide level, can adapt to the sea area with large tide difference and is beautiful. In view of the advantages, the floating breakwater can be used as a permanent building or a temporary building and has wide application prospect in the following fields: (1) the deep water wharf is built in a natural deep water bay with a good wind-sheltering condition, and in order to prevent the influence of leading wind waves all the year round, a small number of floating breakwaters can be arranged in a proper area so as to achieve a better wind-sheltering and wave-resisting effect; (2) the floating breakwater can be used as a temporary berthing wharf of a ship; (3) the floating breakwater can shield water areas such as aquaculture, bathing beaches and the like so as to achieve the double effects of saving investment and keeping good water quality; (4) the construction site of the offshore engineering can use the floating breakwater for temporary shielding, so that the construction operation days are increased, the construction period is shortened, and the benefit is improved; (5) the floating breakwater on the military can be used for shielding the water area of the offshore maneuvering wharf and is also an ideal structural type; (6) the floating breakwater can be used as a wave-proof measure for offshore disaster prevention and emergency. However, there are many factors that limit the application of the floating breakwater, such as that the shield effect is inferior to that of the bottom breakwater, the wave-breaking effect is poor when the wave period is long, the dynamic response under the action of the waves causes fatigue damage to the structure and large anchoring force, so that the maintenance requirement is high, and the safety of the floating breakwater structure itself under the extreme storm condition is difficult to guarantee.
The floating breakwater consists of a floating body and an anchoring system and is used for dissipating waves through the interaction of the floating body and the waves. According to the wave-breaking principle of the floating breakwater structure, the floating breakwater can be divided into three types, namely a wave energy reflection type (such as a floating box type and a floating barrel type floating breakwater), a wave energy loss type (such as a bamboo raft, a floating raft type floating breakwater with waste tires and the like) and a reflection-loss mixed type (such as a fence type and a floating box fence type floating breakwater).
The research results and development conditions of the floating breakwater structure are introduced below, and the wave breaking principle, wave breaking performance and structural stress conditions of the floating breakwater with different structural types are mainly analyzed.
Floating box type (float cylinder type) floating breakwater
The conventional pontoon-type floating breakwater mainly utilizes pontoons to reflect incident wave energy to the open sea so as to reduce transmitted waves, and is generally made of steel plates or reinforced concrete and the like, wherein the width range of a single pontoon is generally 8-16 m, and the underwater depth range is generally 1.5-4.0 m. The most simple structure and most application of the floating breakwater are single floating breakwaters. In order to improve the wave eliminating performance of the floating breakwater and expand the application range of the floating breakwater, scholars at home and abroad improve the structure of the floating box from the aspects of increasing wave reflection, wave energy loss and the like, and the floating breakwater mainly comprises a plurality of floating boxes, a floating box-vertical plate type, a floating box-water plate type, a floating box-other wave energy loss structure type floating breakwater and the like.
(1) Multi-float-box type floating breakwater
Compared with a single floating box type floating breakwater, the multi-floating box type breakwater can improve the wave dissipation performance. Williams et al have conducted numerical simulation studies on hydrodynamic characteristics of a floating breakwater composed of two rigidly connected buoyancy tanks and two unconnected buoyancy tanks respectively by applying a boundary element method according to a two-dimensional potential flow theory, and the results of the studies show that the wave reflection coefficient of a double-buoyancy-tank type floating breakwater is largely determined by the width of the structure, the draught, the distance between the two buoyancy tanks, and the rigidity of an anchor chain. Koftis and Prinos apply a constant Reynolds average N-S method (URANS) to solve the problem of interaction of waves and a fixed double-pontoon type floating breakwater, the influence of the relative width of the breakwater and the relative spacing between front and rear buoyancy tanks on wave performance is researched, and the result shows that the transmission coefficients are reduced along with the increase of the relative width, and the change of the transmission coefficients along with the relative spacing between the front and rear buoyancy tanks is not monotonous. Diamantoulaki et al studied hydrodynamic characteristics of different types of double-pontoon type floating breakwaters by using a method combining three-dimensional hydrodynamic analysis with anchor chain static and dynamic analysis, and the results show that the wave-dissipating effect when the front and rear pontoons are rigidly connected is better than that when the single pontoon is not connected with the front and rear pontoons; the wave-dissipating effect can be improved only by increasing the distance between the front buoyancy tank and the rear buoyancy tank within the medium wave frequency range; the maximum anchor chain force tends to decrease as the distance between the front and rear buoyancy tanks increases. Syed and Mani also analyze the wave-breaking performance of the floating breakwater consisting of three rigidly connected buoyancy tanks by using a boundary element method, and research results show that the distance between the buoyancy tanks has obvious influence on the wave transmission coefficient and the reflection coefficient.
(2) Buoyancy tank-vertical plate type floating breakwater
The buoyancy tank-vertical plate type floating breakwater increases wave reflection and interferes with the motion of a water body nearby the buoyancy tank-vertical plate type floating breakwater through the vertical insertion plates, so that the wave-breaking performance is improved, and the floating breakwater is commonly in a pi shape and a T shape. Christian carries out a series of experimental researches on a floating breakwater connected with a vertical inserting plate, and the results show that the transmission coefficient is smaller when the inserting plate is inserted into water to a larger depth in general, but the transmission coefficient is increased by radiation waves caused by the inserting plate under short-period waves when the inserting plate is inserted into water to a larger depth. The Gesraha carries out numerical simulation research on the pi-shaped floating breakwater with two sides connected with the vertical inserting plates by using a characteristic function expansion method, and the result shows that the transmission coefficient of the inserting plates at two sides can be reduced compared with that of a single floating box type floating breakwater, but the transmission coefficient is increased under the action of oblique short-period waves. Ruol et al conducted a series of physical model experimental studies on pi-type floating breakwaters (anchor chain anchoring and vertical guide pile anchoring) of 8 different sizes, and introduced a parameter of relative period (ratio of incident wave period to structural heave natural period) to provide a calculation formula of transmission coefficient of the pi-type floating breakwaters. Alizadeh et al compare wave dissipation effects of a pi-type floating breakwater anchored by a vertical guide pile and a T-type floating breakwater with the lower part of a buoyancy tank connected with only one inserting plate through a physical model test, and research results show that the wave dissipation effect of the pi-type breakwater is obviously superior to that of the T-type breakwater. Koriam and Rageh specially study the influence of the vertical inserting plates on the wave-breaking performance of the floating breakwater through physical model tests, and the study result shows that the transmission coefficient of the floating breakwater is reduced along with the increase of the number of the vertical inserting plates, and the transmission coefficient can be smaller than 0.25 when 4 layers of vertical inserting plates are available.
(3) Floating box-horizontal plate type floating breakwater
The buoyancy tank-horizontal plate type floating breakwater utilizes the horizontal plate at the bottom of the buoyancy tank to interfere the water body movement around the buoyancy tank and can increase the overall stability of the structure, thereby improving the wave dissipation performance. Ikesue et al propose a double-pontoon type floating breakwater with inner and outer wings, and calculate the transmission coefficient by using a wave numerical value water tank, and research results show that the inner and outer wings have significant influence on the wave-breaking performance of the floating breakwater, and the wave-breaking effect of the double-pontoon type floating breakwater with the inner and outer wings is superior to that of a single-pontoon type floating breakwater with the same size. Physical model tests and numerical simulation researches are carried out on the floating breakwater with the horizontal plate arranged at the lower part of the single buoyancy tank by Dong Hua, and the results show that the transmission coefficient can be reduced by about 0.3 by arranging a layer of horizontal plate at the lower part of the buoyancy tank when the vertical guide piles are anchored, the transmission coefficient is continuously reduced when two layers of plates are arranged, but the reduction range is not obvious, and the wave-absorbing effect of the buoyancy tank-horizontal plate type floating breakwater with the one-layer-plate type vertical guide piles arranged at the lower part of the buoyancy tank for anchoring is ideal; when the anchor chain is anchored, the transmission coefficient of a layer plate is set to be reduced by 0.2 at most, and the motion response and the stress of the anchor chain are both smaller than those of a single floating box type floating breakwater. The boundary element method is applied by the Chinese campsis, the Wang Yongshi and the like to research the interaction problem of waves and the double-buoyancy-tank-horizontal-plate type floating breakwater, the structure comprises a layer of horizontal plate arranged at the lower part of the double-buoyancy-tank, and the numerical simulation result shows that the double-buoyancy-horizontal-plate type floating breakwater has better wave eliminating effect compared with the single-tank-horizontal-plate type floating breakwater under the condition that the total width of the buoyancy tanks is certain, but the motion amplitude is larger and the anchor chain is more stressed. Yangbao et al]The physical model test research is carried out on the floating breakwater with the horizontal plate arranged at the lower part of the double-floating box, and the result shows that the wave dissipation effect of the double-layer plate is better than that of a layer of plateWhen the glass is used, the transmission coefficient can be reduced by about 0.4 at most compared with the case without the horizontal plate; when the relative width is larger than 0.30, the transmission coefficient can be controlled below 0.35, and the motion response is also obviously reduced, but the force applied to the anchor chain is increased.
(4) Floating breakwater with floating box-other wave energy loss structure
The combination of the buoyancy tanks with other wave energy dissipating structures can improve the wave dissipating performance of the floating breakwater, because the combined structure converts the buoyancy tank structure from a wave energy reflection type to a wave energy reflection-dissipation mixed type floating breakwater. The wave energy loss structure mainly comprises a fence structure, a truss structure, a film structure, an air chamber structure and the like.
The buoyancy tank type floating breakwater with the combination of the buoyancy tank and the fence or the truss structure utilizes the fence structure or the truss structure to enhance the turbulent fluctuation of water body and break waves to increase the wave energy loss, thereby improving the wave eliminating performance. Mani provides a Y-shaped floating breakwater with cylinders arranged at the bottom of a buoyancy tank at equal intervals, and a row of cylinders at the lower part can attenuate wave energy, and research results show that the transmission coefficient of the floating breakwater is less than 0.5 when the relative width of the floating breakwater is about 0.15, so that the requirement on the width of the floating breakwater when the wave period is long is reduced. Murali and Mani propose a cage-type floating breakwater consisting of front and rear rows of buoyancy tanks and closely-arranged circular pipes at the lower part of the buoyancy tanks, and research results show that the floating breakwater can achieve the wave-breaking effect when the relative width of most of the structures of the breakwater is 0.4 when the relative width is 0.15. Huang Zhenhua and the like compare hydrodynamic characteristics of the floating breakwater with or without a slotted structure connected to the bottom of the buoyancy tank through physical model tests, and the results show that the slotted structure connected to the bottom of the buoyancy tank can obviously improve the wave-breaking effect of the floating breakwater without increasing the motion response of the floating breakwater. Matsunagaga et al studied the wave-breaking performance of a floating breakwater designed by Saiki steel company of japan, which consists of a pontoon and front and rear steel trusses, and showed that the steel trusses in front of the pontoon can break incident waves to improve the wave-breaking effect.
The single-layer or multi-layer film structure (nylon film, glass fiber cloth and the like) can be used as a floating breakwater to eliminate waves and shield the relevant water area. The single-layer or multi-layer film structure is arranged at the bottom of the buoyancy tank, so that the wave dissipation performance of the floating breakwater can be improved. Hermanson proposes a floating box type floating breakwater with a single-layer film connected to the bottom, and test and research results show that the wave dissipation effect of the floating box type floating breakwater with the single-layer film connected to the bottom under all working conditions is better than that of the floating breakwater without the film, the transmission coefficient is reduced by about 12% on average, and can be reduced by 17% at most. Numerical simulation research is carried out on the floating box type floating breakwater with the bottom connected with the 3-layer film structure by Sung Tai Kee, and the result shows that the 3-layer film structure at the bottom can enhance the overall wave eliminating effect of the floating breakwater under the action of forward waves and oblique waves.
(5) Floating raft type floating breakwater
The floating raft type floating breakwater is a wave energy loss type floating breakwater, and incident waves are attenuated by mainly utilizing the friction action of a floating body and a water body near the water surface and interference on the motion of the water body near the water surface. The buoyant raft type floating breakwater is easy to manufacture and maintain, and has low cost compared with a buoyant box type floating breakwater and a buoyant barrel type floating breakwater, but the wave dissipation effect is relatively poor, and the width of the buoyant raft structure generally can achieve about one time of wavelength to effectively dissipate waves. The research and the application of the waste tire type floating breakwater are relatively more at home and abroad. The waste tire type floating breakwater is divided into a Wave-Maze type, a Goodyear type, a Wave-Guard type and the like according to different arrangement types, wherein tires of the Wave-Guard type are connected into a rigid whole by a rod piece, and the Wave-breaking effect is better compared with other types of waste tire type floating breakwaters. Wu Viden et al improve the steel tube-tire type floating breakwater structure from the aspects of rigidity, gradient, wave-blocking area, self-vibration frequency and the like of the raft body, can increase the reflection and consumption of the floating raft on wave energy, and can ensure that the transmission coefficient of the floating raft reaches 0.22 at the lowest under the unfavorable incident wave condition. The experimental study of Taiwan Shulilun and Shuyijun on a waste tire type floating breakwater shows that the floating breakwater has good wave eliminating effect on sea conditions with small water flow velocity and large wave height. The experimental study of Zhang Yu and Wang Yongchang on the waste tyre floating breakwater shows that the transmission coefficient is less than 0.5 in the experimental range when the width of the breakwater is more than 0.6 times of the wavelength; the influence of the rigidity of the anchor chain and the length of the anchor chain on the transmission coefficient is not obvious; the hawse force increases with increasing wave height and hawse stiffness and decreases with increasing towage length of the hawse.
For the buoyant raft type floating breakwater, other types of buoyant raft type floating breakwaters are proposed in addition to the waste tire type. Wu Jing Nu etc. imitate the structural style of the aquatic plant "buoy", have designed a new form of breakwater, connect multiple round plank flexibility into an organic whole, pave on the surface of water, the research result shows that the structure has effects of dissipating waves, and the effect of dissipating waves is superior to the situation moored to the bank side when adopting the way of mooring under water to fix. Wu-tucha and Wu-Song-ren have carried out physical model test research on the bamboo raft type floating breakwater for shielding wharf construction areas, and test results show that the bamboo raft type floating breakwater has certain engineering practical value as a wave-breaking measure, and the wave-breaking effect in the shelter area is obvious. Hegde et al developed physical model test studies on a buoyant raft type floating breakwater formed by horizontally arranging multiple layers of PVC circular tubes in a staggered manner, and the transmission coefficient was about 0.6 when the relative width of the floating breakwater was 1.0 in the test range.
(6) Other types of floating breakwaters
In addition to various pontoon type (pontoon type) and raft type floating breakwaters, other types of floating breakwaters have been proposed, such as a-frame floating breakwaters, plate-net and perforated floating breakwaters, and the like. The a-frame floating breakwater is proposed by canadian scholars and is designed on the principle that the structure of the breakwater has large moment of inertia. A plate-net type floating breakwater composed of a plate, a net and a sinker is proposed in the Dong sea and Zheng Yanna, wave-dissipating performance of the plate-net type floating breakwater under the combined action of pure waves and wave currents is researched through a physical model test, and research results show that the floating breakwater has a good wave-dissipating effect and can be applied to deep sea aquaculture, but specific design parameters need to be determined according to actual local wave and water flow conditions. On the basis of considering blocking reflection, turbulent energy consumption, wave crest dissipation and the like, Wang Huanyu and Sun Zhaochen propose a porous structure floating dike formed by assembling a plurality of layers of multi-rhombus modules, and carry out physical model test research on the structure floating dike. The design method and the research thought of the floating breakwater structure types provide positive reference for further researching the floating breakwater structure types and improving the wave dissipation effect of the floating breakwater.
The structure is a rigid member composed of two floating square boxes and two layers of horizontal plates, and is connected with water bottom by means of anchor chain to form the floating breakwater, and its wave-breaking performance is related to the factors of relative width, relative wave height and anchor chain rigidity. The existing floating breakwater structure mainly has the following defects:
(1) the existing floating breakwater has the defect of poor wave dissipation effect, especially when the wave period is long. The floating breakwater moves greatly along with the waves when the wave period is long, the reflection effect and the wave energy loss effect on the waves of the ocean are weakened, and the waves penetrating to the breakwater become larger;
(2) when the wave height is larger, the floating breakwater structure is stressed more, and the safety of the structure in the service life is difficult to guarantee. The floating breakwater is anchored by anchor chains or vertical guide piles, the floating breakwater moves along with the waves under the action of the waves, the floating breakwater can move violently under the action of the large waves, the movement of the buoyancy tank is limited, great force can be generated on the structure, and the safety of the structure is difficult to guarantee.
(3) For some floating breakwaters with complex structures and good wave dissipation performance, although the structure types proposed at home and abroad are more, the floating breakwater structure is subjected to large wave force during heavy waves, the safety of the structure is difficult to guarantee, and the safety of the structure is reduced. For example, for a double-buoyancy tank-horizontal plate type floating breakwater, although the wave-breaking effect is improved compared with that of the traditional single-buoyancy tank type floating breakwater, the stress of an anchor chain is increased, the wave force applied to the lower horizontal plate is also large, and the safety of the structure is reduced.
Disclosure of Invention
The purpose of the invention is as follows: in order to overcome the defects in the prior art, the invention provides the porous floating breakwater which has the advantages of good wave-breaking effect, small structural stress, good safety, simple structure, convenience in construction, wide application range and important practical significance for wave prevention of port engineering.
The technical scheme is as follows: in order to solve the technical problem, the porous floating breakwater comprises a plurality of breakwater units which are connected in sequence, wherein each breakwater unit comprises a first buoyancy tank, a second buoyancy tank, a connecting rod and two layers of vertical plates, the first buoyancy tank and the second buoyancy tank are rigidly connected through the connecting rod, the first buoyancy tank and the second buoyancy tank are connected with a mooring balancing weight through anchor chains for mooring, the two vertical plates are fixedly arranged on the connecting rod, a plurality of water passing holes are formed in the two vertical plates, and the opening rate of the water passing holes of the vertical plates is 9% -11%.
Preferably, the first buoyancy tank and the second buoyancy tank are consistent in shape, the width of each buoyancy tank is B, the distance between the first buoyancy tank and the second buoyancy tank is D, and the range of D/2B is 1.0-1.5.
Preferably, the two vertical plates are provided with holes within the height range of the first buoyancy tank and the second buoyancy tank, and the hole opening rate of the water passing holes of the vertical plates is 9-11%.
Preferably, two ends of each of the two vertical plates are respectively provided with a transverse baffle, the transverse baffles and the vertical plates form a Chinese character 'jing', the transverse baffles are also provided with a plurality of water through holes, and the opening rate of the water through holes is 9% -11%.
Preferably, the connecting rod is provided with external threads, the vertical plate is locked on the connecting rod through first locking nuts on two sides, the two ends of the vertical plate are provided with grooves, the two ends of the transverse baffle plate extend to form bosses, the bosses penetrate through the grooves, an L-shaped connecting piece is connected between each boss and the vertical plate, and the L-shaped connecting piece is connected with the bosses and the vertical plate through bolts.
Preferably, the vertical plate has an arc shape.
Preferably, four corners of the vertical plate are respectively provided with a connecting boss, the connecting bosses are connected with supporting rods through bolts, the supporting rods are connected with a connecting sleeve, and the connecting sleeve is locked on the connecting rod through a second locking nut.
Has the beneficial effects that: the porous floating breakwater has the advantages of good wave-breaking effect, small structural stress, good safety, simple structure, convenience in construction and wide application range, and has important practical significance for wave prevention of port engineering. The porous floating breakwater can be applied to water areas with medium wave strength, is applied to the fields of ports and docks, offshore construction, mariculture, seaside bathing grounds and the like, exerts the advantages of no isolation of water body exchange inside and outside ports, reduction of sedimentation inside the ports, small restriction of water depth, quick construction and convenient maintenance, and plays a positive promoting role in port and coastal engineering construction, coastal resource development and utilization and environmental protection in China; the popularization and application of the porous floating breakwater bring great social and economic benefits.
Drawings
FIG. 1 is a schematic structural diagram of the present invention.
Fig. 2 is a side view of the present invention.
FIG. 3 is a schematic structural view of the vertical plate shaped like Chinese character 'jing' in the present invention.
Fig. 4 is a schematic structural view showing that the vertical plate is arc-shaped in the present invention.
Fig. 5 is a graph showing a comparison between the present invention and a conventional single pontoon type floating breakwater.
FIG. 6 is a graph showing the relationship between the vertical plate structure opening and the structure stress influence.
Detailed Description
As shown in fig. 1 and 2, the multi-hole floating breakwater comprises a plurality of breakwater units which are connected in sequence, adjacent breakwater units can be flexibly connected through hinges, each breakwater unit comprises a first buoyancy tank 1, a second buoyancy tank 4, a connecting rod 2 and two layers of vertical plates 3, the first buoyancy tank 1 and the second buoyancy tank 4 are rigidly connected through the connecting rod 2, the first buoyancy tank 1 and the second buoyancy tank 4 are connected with an anchoring counterweight 7 through an anchor guiding hole 5 and an anchor chain 6 for anchoring, the two vertical plates 3 are fixedly arranged on the connecting rod 2, a plurality of water passing holes are formed in the two vertical plates 3, and the opening rate of the water passing holes of the vertical plates is 9% -11%. When the trompil on vertical board 3 is too much, can not block wave propagation well, the energy dissipation effect is not good, when the trompil is too little on vertical board 3, because vertical board 3 bears the impact of wave completely, lead to that vertical board 3 atress is great, easy loss, the security and the durability of reduction structure, long-time use practicality is poor, through long-time research, when the percent opening in water hole is 9% ~11%, the energy dissipation of vertical board is effectual, and the security and the durability of vertical board are good, long service life.
In the invention, the first buoyancy tank 1 and the second buoyancy tank 4 are consistent in appearance and B in width, the distance between the first buoyancy tank 1 and the second buoyancy tank 4 is D, the range of D/2B is 1.0-1.5, the wave transmission coefficient of the double-buoyancy-tank type floating dam is the smallest when the relative distance D/2B between the front buoyancy tank and the rear buoyancy tank is 1.0-1.5, and the wave dissipation effect of the double-buoyancy-tank type floating dam is the best. The vertical plates 3 are provided with holes in the height ranges of the first buoyancy tank 1 and the second buoyancy tank 4, and the wave transmission coefficient of the floating dike is larger than that of the vertical plates when the holes are formed in the height ranges of the floating tanks when the holes are formed in the height ranges of the double buoyancy tanks. Within the test range, the wave transmission coefficient of the floating dike increased by 5.6% on average when the vertical plates were perforated over the full plate height range, compared to when the vertical plates were perforated over the buoyancy tank height range. Therefore, in order to improve the wave dissipating performance of the porous floating breakwater, the porous vertical plate structure arranged between the double buoyancy tanks needs to be provided with holes within the height range of the buoyancy tanks.
In the invention, two ends of two vertical plates 3 are respectively provided with a transverse baffle 9, the transverse baffle 9 and the vertical plates 3 form a Chinese character 'jing', a plurality of water through holes are also arranged on the transverse baffle 9, and the opening rate of the water through holes is 9-11%. By arranging the wave dissipation structure in a shape like a Chinese character jing between the first buoyancy tank 1 and the second buoyancy tank 4, waves can be absorbed in multiple directions, and the impact of the waves is greatly reduced. Be equipped with the external screw thread on connecting rod 2, vertical board 3 is equipped with the groove through the first lock nut 10 of both sides with vertical board 3 locking on connecting rod 2 at the both ends of vertical board 3, and the both ends of horizontal baffle 9 extend there is the boss, and the boss passes the recess, is connected with L type connecting piece 8 between boss and the vertical board 3, is connected L type connecting piece 8 and boss and vertical board 3 through the bolt. Through L type spare, very convenient the unrestrained structure that disappears of "well" font is installed and is dismantled, and all structures can be installed and adjust at the scene moreover, and transportation and construction are all very convenient.
In the invention, the vertical plate 3 is arc-shaped, the four corners of the vertical plate 3 are respectively provided with a connecting boss, the connecting bosses are connected with the supporting rods 11 through bolts, the supporting rods 11 are connected with the connecting seats on the connecting sleeve 12 through bolts, the connecting sleeve 12 is locked on the connecting rod 2 through the second locking nut 14, and the whole structure is similar to an umbrella-shaped structure. For the whole arc-shaped vertical plate 3, the floating dam structure can be reduced along with the wave motion due to the asynchronous wave action, and the wave dissipation effect is better. And because the vertical plate is arc-shaped, the strength structure of the whole vertical plate 3 is also well improved, and the service life is greatly prolonged.
Front and back flotation tank and porous structure combine together, and two flotation tank structures make the inertia grow of floating breakwater on the one hand, and the floating breakwater diminishes along with the motion of wave, and the floating breakwater strengthens the reflex action of wave, and on the other hand the wave sees through preceding flotation tank and is got more by the loss of the vertical board of porous between two flotation tanks, and the wave energy loss has been strengthened to the vertical board of porous between two flotation tanks. The porous floating breakwater forms a wave energy reflection-loss mixed type structure, the wave dissipation effect of the floating breakwater is improved from the aspects of increasing wave reflection to the open sea and enhancing wave energy loss, and meanwhile, the porous structure is small in stress, good in safety, simple in structure and convenient to build.
Wave transmission coefficient CtThe method is an important index of the wave-breaking effect of the floating breakwater, and the index is the ratio of the transmission wave height behind the breakwater to the incident wave height in front of the breakwater. Wave transmission coefficient CtThe smaller the size, the better the wave breaking effect of the floating breakwater. The wave transmission coefficient of the porous floating breakwater and the existing single-pontoon type floating breakwater are contrastively analyzed through a two-dimensional water tank physical model test, as shown in fig. 5, wherein a represents the contrast relationship between the wave transmission coefficient of the porous floating breakwater and the existing single-pontoon type floating breakwater when the wave height is 1.5m, and b represents the contrast relationship between the wave transmission coefficient of the porous floating breakwater and the existing single-pontoon type floating breakwater when the wave height is 2.5 m. Compared with the existing single-floating-box type floating breakwater, the wave transmission coefficient of the porous floating breakwater is reduced by 0.16-0.25, the average wave transmission coefficient is relatively reduced by 33.5%, and the wave breaking effect of the porous floating breakwater is greatly improved compared with the existing single-floating-box type floating breakwater.
FIG. 6 shows the wave force F applied to the first layer of vertical plate when the vertical plate between the double buoyancy tanks is perforated and not perforated when the wave height is 2.5mbWherein a represents a graph of the forward force versus the wave period, and b represents a graph of the reverse force versus the wave period. When two-layer vertical board is set between two buoyancy tanks, the vertical board is compared when the vertical board of first layer receives positive wave power and is reduced 10.1% on average, reverse wave power on average reduces 16.7% when the vertical board of box height within range trompil 10.7% with not trompil. Compare when not trompil with vertical board, during vertical board trompil, the positive and reverse wave power that vertical board received all obviously reduces, and vertical board trompil can improve the security of floating breakwater structure.
Because the porous floating breakwater forms a wave energy reflection-loss mixed type structure, the wave dissipation effect of the floating breakwater is greatly improved from the aspects of increasing the wave energy reflection to the open sea and enhancing the wave energy loss, and the wave dissipation effect of the porous floating breakwater is improved by 33.5 percent compared with the existing single-floating-box type floating breakwater; the vertical plate is provided with the holes, so that the wave force borne by the structure is obviously reduced, and the safety of the structure can be improved through the vertical plate holes. Meanwhile, the porous floating breakwater is simple in structure and convenient to build, the application range of the floating breakwater is expanded, and the porous floating breakwater can be applied to the water areas with medium wave intensity and applied to the fields of ports and docks, offshore construction, mariculture, bathing beaches and the like.
The wave energy reflection-loss mixed structure of the porous floating breakwater greatly improves the wave dissipation effect of the floating breakwater from the aspects of increasing wave energy reflection to the outside sea and enhancing wave energy loss, has small structural stress, good safety, simple structure and convenient construction, can be applied to water areas with medium wave intensity, is applied to the fields of ports and docks, offshore construction, mariculture, seaside bathing grounds and the like, plays the advantages of no partition of water body exchange inside and outside ports, reduction of deposition inside the ports, small restriction on water depth, quick construction and convenient maintenance, and plays a positive promoting role in port and coastal engineering construction in China, coastal resource development and utilization and environmental protection.
The above description is only of the preferred embodiments of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.
Claims (5)
1. A porous floating breakwater is characterized in that: the breakwater unit comprises a plurality of breakwater units which are connected in sequence, the adjacent breakwater units can be flexibly connected through hinges, the breakwater unit comprises a first floating box, a second floating box, a connecting rod and two layers of vertical plates, the first floating box and the second floating box are rigidly connected through the connecting rod, the first floating box and the second floating box are connected with an anchoring balancing weight through anchor chains for anchoring, the two vertical plates are fixedly installed on the connecting rod, a plurality of water passing holes are formed in the two vertical plates, and the aperture ratio of the water passing holes in the vertical plates is 9% -11%; the first buoyancy tank and the second buoyancy tank are consistent in appearance, the width of each buoyancy tank is B, the distance between the first buoyancy tank and the second buoyancy tank is D, and the range of D/2B is 1.0-1.5; the two ends of the two vertical plates are respectively provided with a transverse baffle plate, the transverse baffle plates and the vertical plates form a 'well' -shaped structure, the transverse baffle plates are also provided with a plurality of water through holes, and the aperture ratio of the water through holes is 9% -11%.
2. The porous floating breakwater according to claim 1, wherein: the vertical plates are provided with holes within the height range of the first buoyancy tank and the second buoyancy tank, and the hole opening rate of the water holes of the vertical plates is 9% -11%.
3. The porous floating breakwater according to claim 1, wherein: be equipped with the external screw thread on the connecting rod, vertical board is through the first lock nut of both sides with vertical board locking on the connecting rod, is equipped with the recess at the both ends of vertical board, and the both ends of horizontal baffle extend there is the boss, and the boss passes the recess, is connected with L type connecting piece between boss and the vertical board, is connected L type connecting piece and boss and vertical board through the bolt.
4. The perforated floating breakwater according to claim 1, wherein: the vertical plate is arc-shaped.
5. The porous floating breakwater according to claim 4, wherein: four angles of vertical board all are equipped with the connection boss, and the connection boss has the bracing piece through bolted connection, and the bracing piece is connected with the adapter sleeve, and the adapter sleeve passes through second lock nut locking on the connecting rod.
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CN110457847B (en) * | 2019-08-20 | 2022-12-13 | 交通运输部天津水运工程科学研究所 | Floating breakwater design parameter determination method |
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CN113265981B (en) * | 2021-05-31 | 2022-05-24 | 华南理工大学 | Parabolic double-body floating box type breakwater device and installation method thereof |
CN113818395A (en) * | 2021-07-28 | 2021-12-21 | 广州船舶及海洋工程设计研究院(中国船舶工业集团公司第六0五研究院) | Breakwater floating block unit and floating breakwater structure |
CN113326560B (en) * | 2021-08-02 | 2021-10-29 | 中国海洋大学 | Design method of open-hole breakwater and breakwater |
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