Systems and units for scour protection of marine infrastructure foundations

Abstract

The present invention provides a scour prevention method and system comprising multiple units, each unit comprising a concrete matrix having a pH of less than 12, each unit interlockable with another unit, said system promoting and enhancing marine flora and fauna in the vicinity of offshore underwater infrastructure.

Description

[Background technology]

[0001] Intensifying development of urban foreshores, coastlines, and offshore areas has led to the removal or modification of natural habitats through the addition of complex man-made infrastructure (e.g., energy, aquaculture, seawalls, etc.) in marine environments, a phenomenon known as "marine sprawl." Due to a lack of available structurally sound, ecologically engineered alternatives, coastal and marine infrastructure (CMI) is being designed and constructed with little or no ecological considerations, resulting in a high environmental footprint. More than 50% of CMI is constructed with standard "gray" concrete, which provides an unfavorable substrate for biological recruitment due to its poor surface chemistry and the resulting barriers to settlement of diverse marine larvae. As a result, communities that develop in CMI are typically less diverse than natural assemblages and dominated by nuisance invasive species.

[0002] The offshore wind industry is one of the fastest-growing energy sources globally, alongside traditional oil and gas. While accounting for only 1% of global wind power installations in 2009, offshore wind now accounts for 10% of the global wind energy industry. Since 2013, the global offshore wind market has grown at an average rate of 24%. Europe has been the traditional market for offshore wind power development, accounting for 75% of global wind power installations. However, in recent years, China has become a major player in offshore wind power, installing 2.4 gigawatts (GW) of offshore wind power in 2019 alone (bringing the global installation total to 6.1 GW in 2019).

[0003] Offshore energy and civil infrastructure development requires foundations to anchor constructed infrastructure, such as wind turbines and oil / gas drilling rigs, to the seabed and stabilize cables, pipes, and other civil infrastructure. Various foundations are used depending on sea surface conditions, sea depth, geological factors, and other environmental considerations. Offshore infrastructure foundations are subject to forces from the ocean below, as well as wind action on wind turbines, substations, and drilling rigs. Various types of offshore foundations are used, with pile foundations, gravity / suction foundations, and floating anchors being the three main types. Concrete is widely used in the construction of offshore facilities as a structural component and / or protective mechanism. Scour is a key challenge to address in the offshore industry, as the abrasive nature of the seabed can lead to damage to offshore infrastructure.

[0004] While regulations vary by country, many governments impose similar conditions on developers for the construction and operation of offshore infrastructure. The International Energy Agency (IEA) has set general guidelines outlining environmental impacts, minimum installed capacity, distance from coastline, and bidding systems (IEA) for over 30 member and associated countries, including the UK, Germany, the US, and China. In addition to the general guidelines, specific national and state / provincial policies have been put in place, many of which are based on government efforts to increase renewable energy generation.

[0005] Environmental impact assessments have shown that the construction and operation of offshore infrastructure, such as wind farms, substation rigs, power cables, oil and gas drilling rigs, pipelines, and other forms of civil infrastructure, can have both positive and negative impacts on the surrounding environment. Key issues that arise include the adverse effects of physical disturbance to local habitats and noise pollution above and below the water surface.

[0006] There is a need to provide a scour prevention system that is cost effective, reduces environmental exposure to harmful pollutants, and promotes and enhances marine flora and fauna in the vicinity of offshore marine or underwater infrastructure.

[0007] As an integral part of CMI, nature-inspired solutions need to be developed to allow ecosystems to thrive on high-performance concrete structures, providing complete structural and bio-enhanced concrete solutions designed to promote the development of rich and diverse marine life. Concrete-based scour prevention systems need to be developed that improve water quality around CMI, increase the compressive strength of concrete, and reduce chloride penetration.

[0008] The system of the present invention provides an eco-scour protection unit that takes advantage of the need for scour protection for offshore infrastructure and creates habitats suitable for offshore ecosystems. Summary of the Invention

[0009] The present invention provides a system including a plurality of units, each unit including a concrete matrix having a pH of less than 12, at least one unit of the plurality of units being interlockable with at least one other unit of the plurality of units, the system being a scour prevention system for underwater infrastructure.

[0010] In some embodiments, the average weight of the units of the plurality of units is about 20 to 150 kg.

[0011] In some embodiments, the average weight of the units of the plurality of units is at least about 50 kg.

[0012] In some embodiments, the average weight of the plurality of units is between about 2,000 and 100,000,000 kg.

[0013] In some embodiments, the average weight of the plurality of units is at least about 2,000 kg.

[0014] When referring to a "plurality of units," the system of the present invention shall be understood to include at least 300 units, each unit having the same or different three-dimensional structure formed therefrom and including a concrete matrix having a pH of less than 12.

[0015] Furthermore, each unit of the plurality of units can be interlocked with at least one other unit of the plurality of units. Reference to "interlocking" units should be understood to relate to any type of connection between at least two units of the system of the present invention (one unit above at least one other unit of the plurality of units, one unit below at least one other unit of the plurality of units, one unit locked to at least one other unit of the plurality of units, one unit connected / interconnected to at least one other unit of the plurality of units, one unit linked to at least one other unit of the plurality of units, etc.) such that the movement, displacement, motion, shift, disengagement, misalignment, or actuation of each unit is restricted, inhibited, impeded, or stopped by at least one other unit of the plurality of units.

[0016] It is understood that such interlocking of the units of the system of the present invention is achieved when the system is deployed as a scour protection system for underwater infrastructure (by discharging the units into the aquatic environment at a preferred location). Figures 1-8 show exemplary embodiments of units used by the system of the present invention that enable interlocking.

[0017] Reference to a "scour protection system for marine and underwater infrastructure" should be understood to encompass a system that prevents the loss of marine sediments around any underwater infrastructure placed on a waterbed (seabed, ocean floor, etc.), which when multiple units of the system are deployed (deployed) forms a protective apron, mattress, or any other structure around the base of the underwater infrastructure, with or without the placement of frond devices, or rock and gravel. The system of the present invention is a scour protection system for underwater infrastructure or the environment when multiple units of the system are placed (either randomly, orderly, in a specific arrangement, densely, compactly, orderly, etc.) in or on the waterbed around any underwater infrastructure to prevent the loss of sediments around the underwater infrastructure.

[0018] The term "marine or underwater construction infrastructure" shall be understood to encompass infrastructure of any type, shape, or size defined as suitable for marine or underwater construction, including coastal defense structures such as breakwaters, seawalls, revetments, and dikes, bulkheads, piers, berths, and related infrastructure, as well as infrastructure outside coastal waters such as commercial and international waters. Examples of such marine construction infrastructure include pilings, pier foundations, seaside berms, drilling rig and wind turbine foundations, underwater cable protection and piping casings, mooring units, etc.

[0019] The term "concrete matrix" typically refers to a concrete composition that includes at least one type of cement (e.g., Portland cement or calcium aluminate cement), at least one type of aggregate (e.g., limestone, bluestone), sand (fine aggregate less than 4.75 mm and / or natural or crushed aggregate less than 0-2 mm), and water (potable, containing no more than 1000 ppm chloride or sulfate, and free of harmful substances such as lead, copper, zinc (less than 5 ppm), and phosphates (less than 5 ppm)).

[0020] Reference to an "aquatic environment" should be understood to encompass all types of water bodies, including, but not limited to, marine (including open ocean, deep ocean, intertidal zone, coastal zone, estuaries, salt marshes, coral reefs, lagoons, and mangrove swamps) and freshwater (including stagnant water bodies, flowing water bodies, wetlands, and ponds). The term relates to any depth, any temperature, any time of year, any weather, and any current velocity in said aquatic environment.

[0021] Reference to "flora and fauna" should be understood to encompass any type of plant, organism or animal that is typical of the aquatic ecosystem concerned.

[0022] In some embodiments, the marine or aquatic flora and fauna includes at least one of: (i) engineered species such as corals, oysters, celeriac species, calcareous algae, and barnacles that deposit calcareous skeletons, increasing the structural complexity of structures and creating habitats for other organisms; (ii) filter-feeding organisms such as oysters, mussels, sea squirts, and sponges that use filtering organs to feed while ingesting nutrients and organic particles from the water; and (iii) endolithic / epilithic cyanobacteria, as well as lichens, fungi, and mosses, in some cases when the concrete surface is above water.

[0023] "Promoting the growth of flora and fauna" shall be understood to encompass the qualitative or quantitative promotion, intensification, reinforcement, enhancement, recruitment, or support of the stability, growth, health, and reproduction of flora and fauna already existing or viable in the aquatic environmental ecosystem, as measurable by any parameter known in the art (such as population or species numbers, life cycle, surface coverage, etc.).

[0024] In some embodiments, the promotion of marine flora and fauna promotes mineral deposition on the surface of the structure, resulting in a mineral deposition rate of about 50-1000 gr / m after 12 months at a depth range of 1-10 m. 2 The chlorophyll concentration at the surface of the structure can reach values ​​of approximately 100-800 μgr / m after 12 months at a depth of 1-10 m.

[0025] In another embodiment, the promotion of marine flora and fauna results in a coral colonization rate on the surface of the structure of about 5-25 colonies per 15x15 surface area after 12 months in a range of 1-10 meters of water depth, and a coral colonization rate on the surface of the structure under laboratory conditions of about 5-60% in less than one month.

[0026] In a further aspect, the present invention provides a method for promoting the growth of endolithic and epilithic plants, comprising providing a scour protection system for underwater infrastructure comprised of a concrete matrix having a surface pH of less than 12. It is noted that such infrastructure may also be a Mediterranean land-based bioactive structure (i.e., a bioactive structure above the water surface, but where sufficient humidity and sediment are present to promote the growth of terrestrial plants as in natural systems).

[0027] The term "endolithic and epilithic flora" should be understood to include lichens, fungi, mosses, and blue-green algae. It should be noted that such endolithic and epilithic flora can also grow in terrestrial environments, provided sufficient moisture and sediment are available. In some embodiments, infrastructure such as those described herein above is a "bioactive wall" element designed to rapidly cover the walls of inland buildings with vegetation. Vegetative green cover significantly improves urban landscapes, provides cleaner, healthier air, and reduces the ecological footprint of urban development. The physical and chemical properties of the wall substrate significantly affect its ability to support and promote growth. In some embodiments, such bioactive wall structures induce the natural growth of plants, endolithic algae, lichens, and mosses that attach to the wall. In some further embodiments, the bioactive wall structures have a high degree of complexity and porosity, allowing for the creation of moist niches that support flora without the need for complex soil systems.

[0028] In another aspect, the present invention provides a method for promoting the growth of endolithic and epilithic anaerobic and aerobic flora and fauna, comprising providing a scour protection system for underwater infrastructure comprised of a concrete matrix having a pH of less than 12.

[0029] In a further aspect, the present invention provides a method of scour prevention for underwater infrastructure, comprising providing a system comprising a plurality of units, each unit comprising a concrete matrix having a pH of less than 12, and each unit being interlockable with at least one other unit of the plurality of units.

[0030] In some embodiments the underwater infrastructure relates to marine infrastructure, in some embodiments the underwater infrastructure relates to offshore underwater infrastructure, in some embodiments the underwater infrastructure relates to freshwater infrastructure.

[0031] In some embodiments, the scour prevention system of the present invention has a porosity of at least 30%. In other embodiments, the scour prevention system of the present invention has a porosity of at least 40%. In other embodiments, the scour prevention system of the present invention has a porosity of at least 50%. In other embodiments, the scour prevention system of the present invention has a porosity of between about 30% and about 60%.

[0032] Because the scour prevention system of the present invention includes multiple units, references to "porosity" should be understood to refer to the ratio of the void volume (voids present between the multiple units of the system) of the scour prevention system to the total volume of the scour prevention system, defined as p = Vp / VT. The porosity parameter indicates the relationship between the amount of voids present within a given volume occupied by a bulk scour prevention system (including multiple units). The porosity value of a system including multiple units depends on its physical characteristics and the method of placement. Among the most important physical characteristics that affect the porosity of a system including multiple units are the shape, surface roughness, roundness, size, and mass distribution (grading) of the system units. To provide accurate estimations, the characteristics of the cladding stones are standardized to a normalized grading according to EN 13383, the most widely used standard grading in the industry. Among the standard gradings, those commonly used are those between 60 and 300 kg. Regarding the placement method, a system including multiple units can be randomly, normally, densely, or specially placed. In some embodiments, the placement of a system including multiple units is performed in a random manner.

[0033] Compared to known piled-up scour protection systems, advantages of the system of the present invention, which includes a plurality of units designed such that at least one unit of said plurality of units is interlocked with at least one other unit, include the ability to densify and interlock the scour protection, compared to a random pile of rocks randomly placed on the seabed, which provides a regular and consistent unit shape and grading curve, and further includes the layer packing together with the unit shape and grading controlling the interlocking between units and therefore the shear strength of the units within the scour protection pile and between layers of units.

[0034] It should be noted that the hydraulic stability of the scour prevention system of the present invention is comparable to the hydraulic stability of rock scour prevention systems known in the art, as determined using parameters for evaluating the hydraulic stability of rock structures (typically consisting of a combination of hydraulic parameters and material parameters, including wave and current attack, armor unit properties, cross-section of the system structure, response of the system structure, etc.).

[0035] In some embodiments, the structure described herein is a "live rock" structure, i.e., a structure according to the present invention disposed in an isolated, enclosed marine environment, such as an aquarium (e.g., a saltwater aquarium). Such live rock structures provide several benefits sought by saltwater aquarists in enclosed marine environments. The live rock structures of the present invention provide an excellent biological filter, hosting both aerobic and anaerobic nitrifying bacteria necessary for the nitrogen cycle to process waste. Thus, the live rock serves as the primary biological nitrification substrate or biological filter in a saltwater or freshwater aquarium. Additionally, the live rock structures of the present invention may have a stabilizing effect on water chemistry, particularly helping to maintain a constant pH through the release of calcium carbonate. Furthermore, the live rock structures are decorative elements within the aquarium and provide shelter for the organisms.

[0036] It should be noted that it promotes the growth of endolithic and epilithic anaerobic and aerobic flora and fauna, such as Nitrobacter and Nitrosomonas.

[0037] In some embodiments, the concrete matrix has a pH of less than about 11. In other embodiments, the concrete matrix has a pH of about 9 to about 10.5. In some embodiments, the pH of the concrete matrix is ​​substantially the pH of the entire concrete infrastructure. In other embodiments, the pH of the concrete matrix is ​​substantially the pH of the top surface of the infrastructure. In yet other embodiments, the thickness of the top surface is about 5 cm or greater.

[0038] In some embodiments, the salinity of the aquatic environment is between about 0 and 45 ppt (i.e., the salinity can be 0, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45 ppt).

[0039] The enhancement of flora and fauna concerns aquatic environments exposed to sufficient light, i.e. within the photosynthetically active zone (maximum depth of 0-100 metres) and the area from the seabed to the splash zone, or even above it in the case of bioactive structures supporting terrestrial plants.

[0040] In some embodiments, the at least one unit has a surface roughness of at least 12. In other embodiments, the infrastructure has an RA value of at least 50 microns. Further, the infrastructure has a surface texture with an RA value of 5 to 20 mm.

[0041] In other embodiments, the concrete matrix has a volumetric weight of about 1100 to about 2500 kg / m. In further embodiments, the concrete matrix has a volumetric weight of about 1100 to about 1800 kg / m.

[0042] In a further embodiment, the concrete matrix comprises additives and cement in an amount of from 0 to about 90% by weight of the Portland cement weight, or completely replaces the Portland cement.

[0043] In other embodiments, the concrete matrix comprises at least one of microsilica / silica fume, metakaolin, and calcium aluminate cement. In some embodiments, the silica and / or metakaolin and / or calcium aluminate cement are added to the concrete matrix to replace an equivalent weight percent amount of Portland cement in the matrix. In some further embodiments, the concrete matrix has an average compressive strength of about 20-80 MPa (i.e., about 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, or 80 MPa).

[0044] In some further embodiments, the concrete matrix has a hydraulic penetration resistance of about 5 to 50 mm (i.e., about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 mm) (EN12390-8) under a pressure of 7 bar.

[0045] In other embodiments, the concrete matrix has a chloride penetration resistance of about 500 to 2000 coulombs (i.e., about 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000 coulombs) (ASTM c 1202).

[0046] The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. However, the invention, both as to organization and method of operation, together with its objects, features, and advantages, may best be understood by reference to the following detailed description when read in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0047] [Figure 1] 1A to 1C show structural embodiments (top view, bottom view, and cross-sectional view) of a unit among the plurality of units used in the system of the present invention. [Figure 2]1A to 1C show structural embodiments (top view, bottom view, and cross-sectional view) of a unit among the plurality of units used in the system of the present invention. [Figure 3] 1A to 1C show structural embodiments (top view, bottom view, and cross-sectional view) of a unit among the plurality of units used in the system of the present invention. [Figure 4] 1A to 1C show structural embodiments (top view, bottom view, and cross-sectional view) of a unit among the plurality of units used in the system of the present invention. [Figure 5] 1A to 1C show structural embodiments (top view, bottom view, and cross-sectional view) of a unit among the plurality of units used in the system of the present invention. [Figure 6] 1A to 1C show structural embodiments (top view, bottom view, and cross-sectional view) of a unit among the plurality of units used in the system of the present invention. [Figure 7] 1A to 1C show structural embodiments (top view, bottom view, and cross-sectional view) of a unit among the plurality of units used in the system of the present invention. [Figure 8] 1A to 1C show structural embodiments (top view, bottom view, and cross-sectional view) of a unit among the plurality of units used in the system of the present invention. [Figure 9] 1 shows multiple units of the system of the present invention before being manually dropped into the water from a wooden fennel to simulate a barge-side drop mechanism. [Figure 10] 1 shows the underwater deployed system of the present invention and the interlocking pattern achieved. [Figure 11] 1 shows the underwater deployed system of the present invention and the interlocking pattern achieved.

[0048] It will be understood that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. DETAILED DESCRIPTION OF THE INVENTION

[0049] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the present invention.

[0050] Boundary conditions such as hydrodynamic conditions, soil type, and location were considered during product design, with a primary focus on ensuring the external stability of the scour protection could withstand waves and currents.

[0051] These are technical criteria on hydraulic / soil properties for product identification: defined return period (e.g. 50 years), wind speed (m / s), current speed (m / s), significant wave height and peak period, seabed track velocity, main wave direction, main current direction, soil type, and the effect of depth on the most effective scour protection.

[0052] The product size was derived from the typical size of rocks used for scour protection in reference offshore projects, taking into account various parameters such as average depth, soil type, internal friction angle, estimated length of scour protection, and estimated rock size at locations with different local boundary conditions.

[0053] From these studies, a typical D50 = 0.45m W50 = 276kg (e.g. grading of 200-400kg) is used in European offshore wind farms for water depths greater than 20m.

[0054] Additional relevant data were extracted: pile diameter depends on foundation type, ranging from 10 to 17 m for gravity foundations, and from 4 to 6 m for single piles; D50 is 0.42 to 0.55 m; Dn50 is 0.35 to 0.46 m; W50 is 113 kg to 255 kg (rock ρ (density): 2650 kg / m3); layer thickness: >2D50 2Dn50 = 0.70-0.92 m; layer thickness in five examples: 1.20 m to 1.80 m; length of scour protection. Several calculation formulas have been proposed. One of the most widely used is that proposed by DNV (which depends on the maximum scour depth, the coefficient of internal friction, and the pile diameter).

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[0055] On the other hand, the weight of the cover rock unit considered in Empire Wind is 70 kg. In addition, the internal stability of the scour protection must ensure that fine material does not move through gaps and voids in the protection layer. Flexibility of the scour protection.

[0056] ECOncrete infrastructure is based on a series of concrete mixtures and scientifically based designs that provide suitable biological and environmental conditions for the development of a rich and diverse flora and fauna while reducing the ratio of invasive to native species. ECOncrete infrastructure enhances the ecological value of the constructed structures and mimics natural conditions, promoting the settlement of marine life and the recovery of local ecosystems.

[0057] Bio-enhanced concrete acts as a means of adding resilience to coastal and marine infrastructure by leveraging the growth of ecosystem-engineered biological crusts, which continually grow and layer on the infrastructure. Biogenic sediments are calcium crusts that often form on eco-engineered / bio-enhanced structures, acting as a protective layer that may strengthen the structure while also increasing the infrastructure's carbon storage value. After determining a specific installation site, EConcrete's biology team surveys the area to identify habitats and inhabiting species. Target species are defined in collaboration with local authorities, and the proposed infrastructure is designed according to their preferred habitats.

[0058] Due to the lack of specific locations, the hydrodynamics, wave, current and soil properties are unknown. The units to be designed will accommodate an average rock size of approximately 20-70 kg for scour protection (estimated concrete density: 2,400 kg / m3), placed on top of a filter layer (estimated 5-20 kg) laid on the seabed, and extend for 10 m around the area occupied by the armor layer.

[0059] The hydraulic stability of the ECOncrete Armor units is intended to be achieved not only by their weight but also by their design. The units are cast from C35 / 80Mpa concrete and are designed to withstand being unloaded from the factory to the work dock, onto the ship, and then deployed from the ship to the seabed.

[0060] Marine infrastructure is constructed to strict building codes and standards, with long design lives and intensive use in mind. Examples include ports, marinas, breakwaters, oil and gas platforms, and wind turbines. The application of ecosystem enhancements to these facilities requires compliance with (1) national and international construction standards, such as ASTM International Standards, European Standards (EN), and the American Association of State Highway and Transportation Officials (AASHTO), (2) local construction and labor laws, (3) the structure's design life, and (4) economic feasibility. These strict constraints often result in traditional design and construction processes that preclude ecological design principles and, as a result, can limit the infrastructure's ability to support marine flora and fauna native to the local ecosystem. Scour-resistant cladding is applied to large-scale projects in various climates around the world and is designed to withstand the strong hydrodynamic forces acting on coastal or offshore infrastructure. Concrete units must withstand forces imposed by operational activities, from storage to marine and land-based vessel movements. Additionally, the weight of the individual blocks and their interlocking capacity play a key role in the structural integrity and functionality of the blocks. Because scour protection measures are applied under extreme intertidal conditions (variations in salinity and temperature, wet-dry cycles, hydrodynamic forces, and freeze-thaw cycles), any addition of ecologically relevant features must undergo extensive structural testing. In addition to validating the design life, no compromises can be made to ensure performance results meet or exceed standards.

[0061] Investigation of the free fall of concrete units of the present system underwater and the interlocking of units at the bottom of the water

[0062] Location: All testing took place in Israel. Day 1 of testing (preliminary design evaluation) took place in a 130cm deep pool in Holon, Israel. Day 2 of testing (detailed design evaluation) took place in a 190cm deep pool in Yafit, Israel.

[0063] Date and time: Design evaluation tests were conducted on July 28th, starting at 10:00 local time. Detailed performance evaluation tests were conducted on August 16th, starting at 7:30 local time. Temperature: fluctuated between 30 and 35°C on both days. Weight sensitivity: The scale used to measure the weight of the model unit had a sensitivity of ±30g. Water properties: Freshwater with an estimated density of 1,000kg / m3.

[0064] Material Specifications and Unit Characteristics: The EConcrete scour protection model unit tested was manufactured with the following mix: 1 part sand, 0.6 parts cement, 0.3 parts water, and 0.8g plasticizer. Mix density: 2,400kg / m³. Scale: 1:8.25.

[0065] Manufacturing method: Wet casting into rubber molds. Water properties: Fresh water with an estimated density of 1000 kg / m3.

[0066] The density difference between seawater (1,030 kg / m3) and freshwater (1,000 kg / m3) was not taken into account in the evaluation. To ensure that the relative density of the prototype and the model were the same, the density of the model unit had to be 2,329 kg / m3 instead of 2,400 kg / m3. As a result, the model unit was heavier than it would be in seawater. A tape measure was used to collect data on the deployed diameter. All tests were recorded with strategically placed video cameras that allowed the tests to be tracked. Additionally, photographs and videos were taken of the vicinity of each unit after each drop. The unit's position and orientation were recorded and classified after each drop.

[0067] The pool bottom had rubber matting attached to a plastic sheet to simulate a surface texture. The unit was manually slid into the water from a wooden funnel to simulate the barge-side drop mechanism (Figure 9).

[0068] Preliminary geometric design for design evaluation: The preliminary geometric design of the unit was carried out based on the following criteria: geometric potential for confirming biological characteristics, feasibility of mass production and operation, structural robustness for impact with the bottom surface or other units after free fall in water, and interlocking of at least two units of the system.

[0069] The designs shown in Figures 1 to 8 were developed and tested during a preliminary evaluation phase. Measurements are in millimeters and were taken from scale models.

[0070] Single-unit alignment test protocol: A single unit of each type was dropped at three different alignments to test the effect on alignment at the bottom of the pool. This procedure was repeated three times for each design.

[0071] Group Drop Test Protocol: A group of 40 units was dropped into the water through a funnel. The funnel was 15cm high above the water surface. The resulting spread of the units was measured in three variables: spread diameter, pile height, and interlocking ability. This procedure was repeated three times for each design.

[0072] Test Results: Units tend to orient themselves towards surfaces that distribute mass evenly, and if possible, land on surfaces with angular surfaces rather than parallel surfaces, resulting in less drag. The direction of the drop has little or no effect on landing orientation. Units with an off-center center of gravity tend to rock and flip more than other units.

[0073] Units with slots and sharp angles appear to interlock better. Dropping multiple designs together does not significantly affect the quality of the results.

[0074] Figures 10 and 11 show the deployment of the system of the present invention as a scour protection and the interlocking pattern of said units.

[0075] While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will occur to those skilled in the art, and it is therefore to be understood that the appended claims are intended to cover all such modifications and changes that fall within the true scope of the present disclosure.

Claims

1. 1. A system comprising a plurality of units, each unit comprising a concrete matrix having a pH less than 12, each unit interlockable with another unit, said system being a scour protection system for underwater infrastructure.

2. The system of claim 1, wherein the average weight of the units is between about 20 kg and about 150 kg.

3. 3. The system of claim 1 or 2, wherein the average weight of the units is at least about 50 kg.

4. 4. The system of claim 1, wherein the plurality of units has an average weight of at least about 2000 kg.

5. 5. The system of claim 1, wherein the pH is less than about 11.

6. The system of any one of claims 1 to 5, wherein the pH is about 9 to 10.

5.

7. 7. The system of claim 1, wherein the pH of the concrete matrix is ​​the pH of the top surface of the unit.

8. The system of claim 1 , wherein the surface has a thickness of at least about 5 cm.

9. 9. The system of any one of claims 1 to 8, wherein the salinity of the aquatic environment is about 0 to 45 ppt.

10. 10. The system according to claim 1, wherein the unit has a surface roughness with a roughness rating of at least 12.

11. 11. The system of any one of claims 1 to 10, wherein the concrete matrix has a weight per volume of about 1100 to about 2700 Kg / m3.

12. 12. The system of any one of claims 1 to 11, wherein the concrete matrix has a weight per volume of about 1100 to about 1800 Kg / m3.

13. 13. The system of any one of claims 1 to 12, wherein the concrete matrix comprises 0 to about 90% Portland cement.

14. 14. The system of any one of claims 1 to 13, wherein the concrete matrix has an average compressive strength of about 30 to 80 MPa.

15. 15. The system of any one of claims 1 to 14, wherein the concrete matrix is ​​capable of promoting marine or aquatic flora and fauna.

16. 16. The system of claim 15, wherein the marine or aquatic flora and fauna is selected from engineered and native species, corals, and filter-feeding organisms.

17. 1. A method of scour protection for underwater infrastructure, comprising providing a system comprising a plurality of units, each unit comprising a concrete matrix having a pH of less than 12, and each unit being interlockable with at least one other unit of the plurality of units.

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