CN-121853510-B - Semi-cylindrical shell floating breakwater with multistage energy dissipation and vibration reduction and flexible anchoring system

CN121853510BCN 121853510 BCN121853510 BCN 121853510BCN-121853510-B

Abstract

The invention discloses a semi-cylindrical shell floating breakwater with a multistage energy dissipation vibration reduction and flexible anchoring system, and belongs to the technical field of ocean engineering. The breakwater aims to solve the technical problems that the existing floating breakwater has limited energy dissipation efficiency under complex sea conditions, the whole motion response is severe and the anchoring system is stressed too much. The breakwater comprises a floating body unit, an energy dissipation and vibration reduction system and a flexible anchoring system, wherein the floating body unit is provided with a semi-cylindrical shell and a buoyancy tank, a plurality of rows of wave dissipation holes are formed in the wave facing side of the shell, the energy dissipation and vibration reduction system is arranged below the buoyancy tank and comprises a vertical connecting rod, a horizontal through hole vibration reduction heave plate, a first vibration reduction damper and a vertical through hole wave dissipation plate, the first vibration reduction damper and the vertical through hole wave dissipation plate are arranged on a section of the vertical connecting rod, and the flexible anchoring system comprises anchor blocks arranged on a seabed, an anchor chain for connecting the anchor blocks with the buoyancy tank and a second vibration reduction damper arranged on the anchor chain. The breakwater is mainly used for wave protection and energy dissipation in ports, coasts and offshore engineering areas.

Inventors

Wan Zhinan
YANG BIAO
WANG YI
XIA WUMIN
Tang Chaozhan
LIU XIAOLEI
WU CHEN
Ye Yatu
LI MUSHI

Assignees

中交第四航务工程勘察设计院有限公司

Dates

Publication Date: 20260508
Application Date: 20260317

Claims (7)

1. A semi-cylindrical hull floating breakwater with a multi-stage energy dissipating vibration damping and flexible mooring system, comprising: the floating body unit comprises a semi-cylindrical shell and a buoyancy tank connected to the bottom of the semi-cylindrical shell, wherein the wave-facing side of the semi-cylindrical shell is provided with a plurality of wave-dissipating holes; energy dissipation vibration damping system, it locates the buoyancy tank below, includes: the plurality of vertical connecting rods are distributed in a matrix manner, the top end of each vertical connecting rod is connected with the bottom of the buoyancy tank, and the bottom end of each vertical connecting rod extends downwards; At least two layers of horizontal through hole vibration reduction heave plates are fixedly sleeved on the plurality of vertical connecting rods at intervals along the vertical direction, and divide each vertical connecting rod into a plurality of sections; The first vibration reduction dampers are respectively arranged on the sections of the vertical connecting rods and positioned between two adjacent layers of horizontal through hole vibration reduction heave plates and between the buoyancy tank and the uppermost layer of horizontal through hole vibration reduction heave plates; The plate surface of the at least one vertical through hole wave-dissipating plate is parallel to the wave incident direction, and two ends of the vertical through hole wave-dissipating plate are respectively connected with two first vibration reduction damper shells positioned at the same height; The flexible anchoring system comprises an anchor block arranged on the seabed, an anchor chain connecting the anchor block with the bottom of the buoyancy tank and a second vibration reduction damper arranged on the anchor chain; The vertical connecting rod comprises an inner layer cylinder and an outer layer sleeve which are coaxially arranged, an annular containing cavity is formed between the inner layer cylinder and the outer layer sleeve, magnetorheological fluid is filled in the annular containing cavity, a piezoelectric sensing layer is arranged on the outer wall of the inner layer cylinder, and a first electrode layer is covered on the outer surface of the piezoelectric sensing layer; The inner cylinder is connected with the outer sleeve at a plurality of positions axially spaced by flexible fold membranes, and the flexible fold membranes seal the annular accommodating cavity and axially divide the annular accommodating cavity into a plurality of independent damping adjustment sections; The vertical connecting rod is provided with a controller, the signal input end of the controller is connected with the piezoelectric sensing layer, and the output end of the controller is connected with the first electrode layer and the second electrode layer of each damping adjusting section; Each energy dissipation cylinder consists of an outer frame and a plurality of layers of metal grid arranged in a staggered way in the outer frame, a catalytic coating is attached to the surface of a grid wire of the metal grid, and porous elastic damping material blocks are filled among staggered gaps of the metal grid; the frame is connected with vertical connecting rod through quick latch mechanism, and quick latch mechanism is a plurality of eccentric cam hasp of circumference equipartition, and the pivot of every hasp runs through the wallboard and the inboard end connection of outer frame sticiss the dish in advance, and when the hasp was closed, the pivot drive sticiss the dish in advance along the axial compress tightly on vertical connecting rod.
2. A semi-cylindrical shell floating breakwater with multi-stage energy dissipating vibration damping and flexible mooring system according to claim 1 wherein the buoyancy tanks are provided on both sides with connectors for connecting adjacent floating body units, and rotary dampers are provided between the connectors.
3. The semi-cylindrical shell floating breakwater with the multi-stage energy dissipation vibration reduction and flexible anchoring system according to claim 1, wherein the flexible anchoring system further comprises a gravity anchor base platform arranged on a seabed, anchor blocks are distributed on the upper surface of the gravity anchor base platform in a dispersed mode through universal hinges, an anchor chain is divided into an upper chain segment and a lower chain segment, a second vibration reduction damper is connected between the upper chain segment and the lower chain segment, and the lower end of the lower chain segment is connected with the center of the gravity anchor base platform through a spherical bearing hinge.
4. The semi-cylindrical shell floating breakwater with the multi-stage energy dissipation vibration reduction and flexible anchoring system as claimed in claim 1, wherein a closed air cabin communicated with the buoyancy tank is arranged in the inner cavity of the semi-cylindrical shell, the air cabin is connected to an air storage tank arranged in the buoyancy tank through a first pipeline, the air storage tank is connected to an air compressor arranged in the buoyancy tank through a second pipeline, the inner end of the wave dissipation hole is communicated with the air cabin, and the wave dissipation hole is communicated with the air cabin.
5. The semi-cylindrical shell floating breakwater with multi-stage energy dissipating vibration damping and flexible mooring system according to claim 1 wherein the open cell design of the horizontal through hole vibration damping heave plate is parametrically adapted according to the characteristic wave height H and average wave period T of the target sea area, wherein: The aperture d of the opening is H/15-d-H/8, the aperture on the same layer plate is increased in a gradient way along the center of the plate to the edge, and the aperture of the edge area is 1.2-1.5 times of that of the center area; The overall porosity eta of the plate is optimized based on the wave period T, and the relation formula eta=k×ln (T) +b is satisfied, wherein k and b are coefficients related to the energy dissipation cylinder level, the through hole rate of each layer plate from top to bottom is gradually decreased, and the gradient difference of the through hole rates is 5-10%.
6. The semi-cylindrical hull floating breakwater with multi-stage energy dissipating vibration damping and flexible anchoring system according to claim 1, further comprising a structurally optimized configuration of the system according to water depth and geological conditions: When the deployed water area is a shallow water area with the water depth less than 20m, adopting simplified two-stage energy dissipation configuration, namely arranging two layers of horizontal through hole vibration reduction heave plates and one layer of vertical through hole wave dissipation plates, wherein the basic thickness t of the horizontal through hole vibration reduction heave plates is increased along with the increase of the water depth h, and the conditions that t=t 0 +0.5× (h-10), wherein t 0 is the basic thickness and the unit mm are satisfied; when the deployed water area is a deep water area with the water depth of more than 30m, adopting enhanced three-stage energy dissipation configuration, adding a third layer of horizontal through hole vibration reduction heave plate, and enabling the lowest vertical through hole wave dissipation plate to extend downwards to a position 3-5m above the seabed surface; The design weight W of the anchor block is optimized according to the submarine geological type, wherein in a muddy soft soil foundation, W is more than or equal to 1.5×Fmax/mu s , in a sandy foundation, W is more than or equal to F max /μ s , F max is the maximum anchor chain tension, and mu s is the anchor block friction coefficient of the corresponding foundation.
7. A semi-cylindrical hull floating breakwater with multi-stage energy dissipating vibration damping and flexible anchoring system according to claim 2, wherein: The rated damping force F d of the first vibration reduction damper and the second vibration reduction damper is required to be 0.3 multiplied by F w ≤F d ≤0.7×F w , wherein F w is the designed wave impact force which is calculated according to Morrison equation and acts on the connecting position of the corresponding components; The torsional rigidity K t of the rotary damper is matched with the size of the connected floating body unit, and an empirical formula K t =C×ρ×g×B 2 xL xD is satisfied, wherein ρ is the density of sea water, g is the gravity acceleration, B is the width of a single floating body unit, L is the length, C is the correlation coefficient with the value range of 0.05-0.15, and D is the draft of the floating body unit.

Description

Semi-cylindrical shell floating breakwater with multistage energy dissipation and vibration reduction and flexible anchoring system Technical Field The invention relates to the technical field of ocean engineering. More particularly, the present invention relates to a semi-cylindrical hull floating breakwater with a multi-stage energy dissipating vibration damping and flexible mooring system. Background In recent years, a floating breakwater has been attracting attention as a marine structure that is suitable for a deep water environment and reduces the influence on the ecology of the seabed. The basic working principle is that a floating body floating on the water surface is used for obstructing wave propagation, and the motion of a water particle is interfered by the motion of the floating body, so that wave energy is consumed, and the purpose of wave dissipation is achieved. Compared with the traditional bottom-sitting breakwater, the floating structure has the advantages of strong adaptability to water depth change, low requirement on submarine geological conditions, convenient and movable construction, relatively small influence on hydrodynamic environment and ecology of sea areas and the like. However, in practical engineering application and long-term operation, the conventional floating breakwater still generally faces a plurality of technical problems which are not properly solved, and the full play of the performance and the improvement of the reliability are restricted. First, in terms of wave-absorbing performance, conventional floating breakwaters rely primarily on reflection of the above-water portion of the floating body and rigid body motions (e.g., heave and pitch) of the floating body as a whole under wave action to dissipate energy. The energy dissipation mechanism is single, has a certain effect on short-period waves, but has obviously reduced reduction efficiency on the waves with concentrated energy and longer period. The root cause is that wave energy is not uniformly distributed in the water body, but decays exponentially from the water surface to the water depth, and the traditional floating body structure is difficult to effectively intervene and dissipate the wave kinetic energy of the middle and lower water bodies. Therefore, the existing design often has the problems of narrow wave-absorbing frequency band and limited long wave energy-absorbing effect, and is difficult to meet the engineering requirements of open sea areas or environments needing to cope with complex wave spectrums. Second, dynamic response control of the structure under wave action is another significant challenge. The float is excited by continuous wave load and produces multiple degrees of freedom including heave (up and down motion), pitch (back and forth pitch) and roll (side to side). The overlarge movement amplitude can not only reduce the stability of the shield water area at the rear part and influence the poising condition, but also lead to stress concentration and easy fatigue of the connecting part of the structure, and the damage and even the destruction of the structure can be caused for a long time. The prior art generally focuses on inertial damping of motion by increasing the size or mass of the float, but this adds significantly to the amount of material and cost and is not effective in damping high frequency vibrations. On the premise of not obviously increasing dead weight and cost, the vibration caused by waves of the structure in multiple directions is effectively attenuated, and the vibration damping device is a continuously existing technical difficulty. Furthermore, the long-term reliability and viability of the mooring system is under serious test. As a key subsystem for fixing the position of the floating breakwater, the mooring system directly bears the dynamic environmental load transmitted from the floating body. Under the alternating action of wind, wave and current, especially in extreme sea conditions, the anchor chain bears great cyclic tension and impact load, fatigue damage and even fracture are very easy to occur, and the whole breakwater structure is caused to drift and lose effectiveness. Conventional mooring designs have focused on providing sufficient static mooring forces and lack a systematic solution for how to effectively cushion and dissipate dynamic impact loads acting on the chain. The anchor chain becomes a weak link in the floating breakwater system, and the fatigue life problem directly affects the operation safety and maintenance period of the integral structure. In addition, the problems are related to each other, and the difficulty of comprehensive solution is increased. For example, insufficient wave-absorbing efficiency means that more wave energy needs to be carried by the structure itself and its mooring system, exacerbating the structure vibrations and chain loads, while excessive structure movement can adversely affect the stability of the wave-absorbin