TECHNICAL FIELD

The present invention relates to particulate retention systems and uses therefor. More particularly, the present invention includes improved methods and apparatus for retaining and stabilising particulate. In addition the present invention provide new applications for the particulate retention systems of the present invention including erosion control and filtration and/or liquid treatment applications.

BACKGROUND ART

For clarity, the present invention will herein be primarily described with respect to the retention and stabilisation of particulates such as soil, rock, vegetation, detritus and the like, for which the present invention has particular application. However, this should not be seen to be limiting as the present invention may also have use in retention of other particulate or indeed other applications altogether.

The term "soil", as used herein should be understood to mean any soil, rock, sand, sediment, detritus or other particulate and should not be seen to be limiting.

The often unstable soil of hillsides, embankments, riverbanks, beaches and the like can quickly and unexpectedly erode or collapse and affect nearby roading, buildings, utilities (e.g. power lines), re-vegetation and other construction. Sufficient erosion can lead to the collapse of the construction itself, potentially leading to loss of life, property, or at least an expense in rebuilding.

The retention and stabilisation of even relatively stable soil can also be a substantial problem in environments where the soil is exposed to rain, ice, earthquakes, heat or combinations thereof. These environmental factors can destabilise the soil and cause erosion or collapse.

The collapse or erosion of roadsides, riverbanks and embankments is a common problem that has typically been addressed by building some form of barrier between the soil and nearby road or construction.

One exemplary method used is providing concrete walls between the unstable region and the nearby construction, e.g. concrete walls are commonly used to reinforce riverbanks.

Another method involves the use of steel netting fences placed between the unstable region and the nearby construction, e.g. netting fences may be placed alongside roads to catch rock and soil falling from an adjacent cliff or hillside

Yet another common method may involve pinning netting or mesh to hillsides to hold the soil in place. Re-vegetating the hillside is also another commonly used option, though is not effective on arid, rocky or highly unstable surfaces.

An exemplary mesh system used to retain soil is described in US5797706 by Segrestin and Jailloux and is preferred over concrete walls in many applications as the mesh allows for vegetation to grow through the mesh and thus provide a relatively more aesthetic facing while also improving stability. Such mesh may also be significantly less expensive to manufacture and use than concrete barriers.

Another method of soil stabilisation involves the use of a rigid cellular framework, such as described in United States Patent No. 4,717,283 by Bach. The Bach framework is placed on a riverbank and has many vertically orientated cells that collect soil, gravel and the like. The riverbank is thus built up and reinforced as the framework fills with rock and sediment.

However, these methods may not be effective in all applications and can be expensive and difficult to implement. For example, the Bach system can be expensive to build and may not be effective where the gradient of the bank is too steep for soil to effectively collect in the cells. The Segrestin and Jailloux system may not be effective in retaining small or fine soil and does not alter the shape of the hillside to improve stability.

Furthermore, none of the prior art systems provide for a way to effectively re-vegetate eroded hillsides or rock-faces where steep, loose and often arid soil or rock fails to retain sufficient water to maintain growth of plants. This problem has been partially addressed in the past by attempting to 'glue' the vegetation to the surface by spraying or coating the surface with a combination of non-toxic glue and plant seed. However, the glue process can be expensive and may not work for all surface-types.

It would thus be advantageous to provide a method and apparatus for the retention of soil and other particulate that can be adapted to a wide range of gradients and can be quickly and easily assembled to suit the application.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

It is acknowledged that the term 'comprise' may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term 'comprise' shall have an inclusive meaning - i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term 'comprised' or 'comprising ¹ is used in relation to one or more steps in a method or process.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF INVENTION

According to a first aspect of the present invention there is provided a framework for retaining particulate to a work surface inclined with respect to horizontal, the framework including:

- two sidewalls having first and second opposing edges, the second edge configured to rest on the work surface;

- a connecting wall joining the sidewalls and extending there between, the sidewalls and connecting wall defining a retention space there between for retaining the particulate; and wherein the first edge of each sidewall is angled to taper away from the connecting wall.

Most preferably, the sidewalls and connecting wall are adapted to be releasably connected to one another.

The sidewalls preferably taper away from the connecting wall to allow particulate to be retained in the retention space to a greater depth adjacent the connecting wall than at the opposing end. Therefore, when the framework is located on the work surface the particulate can be deposited in the retention space up to the upper edges of the walls (i.e. the second edges) and will create an upper particulate surface at a relatively shallower gradient than that of the work surface itself.

The angle of the first edge of the sidewalls in relation to the second edge is dependent on the angle of the work surface on which the framework is fixed, the angle being such that the slope of the first edge becomes substantially horizontal in relation to the slope of said work surface.

In a preferred embodiment the framework can be used to convert a surface with a steep gradient to a relatively shallower gradient by filling the retention space up to the upper edges of the walls. This reduced gradient can improve the stability of a loose or otherwise unstable work surface, e.g. a rocky hillside.

Another preferred embodiment utilises the retention space as a catchment area in a filtration system, the retention space being unfilled forms an area where sediment and other matter are captured, yet smaller particulate and liquid may pass from the retention space via drainage apertures in the connecting wall. In another preferred embodiment the framework is situated in a flow of liquid, the retention space may be left empty and the framework anchored to the work surface. The flow of liquid slows as it passes through the connecting wall releasing any suspended particulate which is then deposited behind the connecting wall, resulting in active recovery of particulate from the liquid flow.

As used herein, the term "wall" refers to any surface, or series of surfaces capable of forming a barrier or partition for inhibiting movement of the particulate there through.

The term "connecting wall" refers to a surface which connects two or more sidewalls and extends there between, the position of the connecting wall may be at any point along the sidewalls. Preferably the connecting wall is positioned at or substantially adjacent the front edge of the sidewalls.

As used herein, the term "edge" should not be seen to be limited to mean 'sharp ¹ or 'narrow' as the edge may be wide and flat without affecting the functionality of the framework. It should also be appreciated that only a portion of the second edge needs to rest on the work surface for the framework to function.

Where an edge is 'narrow' or 'sharp', a flange or similar substantially flat member may be attached to the edge. The provision of such a flange reduces the potential for the 'sharp' upper (first) edge to damage, for example, an animal's feet when walking on the edge.

The term "flange" as used herein, should be understood to mean any ledge, plate, rib, rim or other member protruding from and extending along at least part of the sidewall.

Preferably, the side and/or connecting walls are constructed from a non-biodegradable material such as galvanized steel or other weather and/or corrosion-resistant material. Preferably, the sidewalls are connected to the connecting wall in an interlocking engagement.

Preferably, the sidewalls are releasably connected to the connecting wall.

Preferably, the large end of the sidewalls is substantially matched in height with the height of the connecting wall.

The sidewalls may be connected to the connecting wall in a variety of different ways without departing from the scope of the present invention.

In some embodiments each of the sidewalls may be connected to the connecting wall via a suitably configured connector.

In one preferred embodiment, the sidewalls may be connected to the connecting wall via the interlocking engagement of a protrusion on each sidewall with a corresponding aperture on the connecting wall, or vice versa.

Preferably, the protrusion is a flat tab or the like which can be inserted through the aperture and then bent or folded to secure the walls together. Providing such tabs can ensure the walls can be manufactured and transported separately but can be quickly and easily connected together in a modular and interlocking arrangement. In comparison, the prior art methods of building walls, fencing or the like can be difficult to assemble in an accurate and modular way as the walls or mesh are often required to cover large areas continuously.

Preferably, the sidewalls may be adapted for securing the framework to the work surface. In one preferred embodiment the sidewalls may have a flange with an aperture therein for receiving a peg, pin, screw or the like, which is driven or screwed into the work surface. The framework may thus be 'attached' to the work surface via the flange without requiring expensive and difficult embedding of the framework in the work surface.

Preferably, the connecting wall is joined to the sidewalls so that the face of the connecting wall is backwardly sloped towards the tapered end of the sidewalls. In other words the face of the connecting wall is joined to the sidewalls so as to incline back into the retention space created by the sidewalls and connecting wall.

In a preferred embodiment the retention space is filled with particulate when in use and the weight of said particulate may bear on the connecting wall potentially buckling or bending the connecting wall. Thus, in comparison to a connecting wall extending perpendicular to the second edges, inclining the connecting wall toward the retention space reduces the effective torque placed on the connecting wall about the connection to the sidewalls.

It will be appreciated that the connecting wall need not be connected to an 'end' of the sidewalls and instead can be positioned at any point along the length of the sidewalls.

Preferably, the connecting wall has one or more drainage apertures therein and more preferably, a plurality of said apertures.

In some embodiments said sidewall may have one or more drainage apertures therein.

The provision of drainage apertures in the connecting wall and/or sidewalls allows liquid and/or fine particulate to pass through the apertures while preventing larger particulate from passing through. Thus the drainage apertures may be sized and/or positioned so as to retain particulate and/or control the rate by which liquid (and any suspended material of a small enough size) passes through the connecting wall and/or sidewalls.

In some embodiments decreased flow rates may cause deposition of fine particulate material within the retention space notwithstanding the size of the particulate would otherwise pass through the aperture. The apertures thereby provide a means for filtering and collecting particulate suspended in the liquid flow.

This ability for liquid to pass from the retention space is useful in, for example, preventing soil erosion on riverbanks where large amounts of particulate are water- borne, e.g. as sediment. The sediment collects in the retention space while the water flows through and the particulate can build-up to act as a barrier between the vulnerable riverbank and the water flowing past. Another example illustrating the usefulness of drainage of the retention space is when filtration of a liquid is desired, the retention space captures and retains particulate suspended in a liquid flow, whilst allowing the liquid to pass through, additional matter added within the retention space may be used to further filter and/or alter the composition of the liquid.

The apertures may also be sized and located to regulate the flow of water or other liquid as well as control the size of particulate retained within the retention space. The apertures can thus be used to regulate the amount of water contained in the retention space and therefore can be useful in re-vegetation applications by regulating the amount of water retained in the framework and therefore the amount of water available for plant growth. The framework can also be secured to a steep, arid or rocky face and used to retain sufficient water to promote plant growth. In one embodiment, the apertures are spaced from the second (lower in use) edge of the sidewalls. Thus, water is retained in the retention space to a level just below the apertures, any further increases in non-absorbed water content is drained through the apertures.

In another preferred embodiment, the drainage apertures may be sized and positioned to control the size of solid matter retained by a particular retention space and/or the flow rate of a liquid.

According to a further aspect of the present invention there is provided a liquid filtration and/or treatment system wherein the frameworks are arranged to form a cascaded assembly of particulate retention frameworks with the uppermost, or first, retention space(s) having apertures sized to assist with capture of the largest solid matter, and each of the subsequent retention space(s) in the cascade having drainage apertures configured to assist with retaining correspondingly smaller solid matter.

In another embodiment, the drainage apertures may be sized and spaced to control the flow of liquid through the connecting wall, slowing the flow of liquid downstream of the connecting wall, allowing suspended particulate to be released from the liquid flow.

Where an edge is 'narrow' or 'sharp', a flange or similar substantially flat member may be formed from or attached to the edge. The provision of such a flange reduces the potential for the 'sharp' upper (first) edge to damage, for example, an animal's feet when walking on the edge.

Preferably, in use, the flange also protrudes toward the retention space to assist in retaining particulate therein. Preferably, a flange may extend along an edge the connecting wall and more preferably protrudes toward the retention space. Such a flange or ledge assists in retaining the particulate in the retention space in a similar way to the ledge or plate attached to the sidewalls.

The length of the sidewalls can be varied to suit the application. In some applications where the sidewalls are relatively long, the force of the particulate bearing on the sidewalls may be sufficient to bend, buckle or detach the sidewalls from the work surface. To alleviate this problem, the framework is preferably provided with one or more cross-bracing members, extending between and connected to either sidewall.

Preferably, the cross-bracing includes apertures or the like for facilitating drainage there through. The cross-bracing may thus serve a similar function to the connecting wall by providing apertures, preferably similar to those provided on the connecting wall as aforementioned.

Preferably, the cross-bracing is connectable to the sidewalls via mating engagement of a protrusion on either end of the cross bracing with corresponding apertures in the sidewalls or vice versa, e.g. the cross-bracing may be attached using folding tabs similar to that connecting the sidewalls to the connecting wall.

It should be appreciated that the connecting wall may act as a cross-bracing member and vice versa without departing from the scope of the present invention.

According to one preferred embodiment of the present invention there is provided a particulate retention system including a plurality of frameworks as hereinbefore described. Preferably, the frameworks of the particulate retention system may be arranged in a chain or network over the work surface. The network may be in the form of an array or chain of frameworks. The array or chain of frameworks may form a 'stepped' or 'terraced' surface while retaining particulate (e.g. soil) in each retention space of each framework, thereby providing a potentially more productive surface than an otherwise steep, unstable surface.

The array or chain of frameworks can thus be used act to reduce the effective gradient of the work surface to assist in retaining particulate and stabilise the work surface.

As used herein the term 'chain' or 'chained' with reference to the present invention refers to a number of frameworks connected to one another to form an interconnected series of laterally or longitudinally frameworks. It will be appreciated that longitudinal means in a direction extending in line with the longitudinal axis of the sidewalls and conversely lateral means in a direction extending in line with the lateral axis of the sidewalls.

It should be understood that each of the frameworks constituting the network of frameworks need not be the same (i.e. the network may be a plurality of chained frameworks next to one another), nor does the network of frameworks specifically have to be in a cascaded arrangement. However, in some specific embodiments such as in a filtration system the series of frameworks may have a cascaded relationship.

Preferably, laterally aligned adjacent frameworks in a series may be joined together, with the one sidewall being shared by an adjacent framework to form a chain. Preferably, a longitudinally aligned series of frameworks may have a coupling for attaching the sidewalls of one framework to the connecting wall of an adjacent framework to form a chain.

In one preferred embodiment the coupling may be a recess in the first edge on the sidewall. The recess may have at least one securement tab engageable with an aperture in the connecting wall of the adjacent framework or vice versa, wherein said recess is located on the sidewall at the end distal to the connecting wall of the first framework and is inclined from the first sidewall edge toward the retention space of the . second framework, the second framework connecting wall resting on the inclined edge and being connected to the sidewalls of both the first and second frameworks.

Preferably, the coupling between the first and second frameworks is configured such that the first and second frameworks are movable relative to each other.

In a further embodiment, the first and second frameworks may be movable relative to each other to allow the second edges of the first framework to be inclined with respect to the second edges of the sidewalls of the second framework.

As the frameworks are movable relative to each other, the particulate retention system may extend over a surface with an irregular gradient while ensuring the lower edges of each framework are substantially abutting the work surface.

In a preferred embodiment a chain or network of frameworks may thus be formed that can extend along x axis and/or y axis over the work surface, each framework retention space forming a particulate retention cell that when filled with particulate, will have a shallower gradient than the corresponding region of work surface on which it rests. A chain of frameworks can thereby form steps or pathways over, for example, a hillside or riverbank, while a 'network' of frameworks provides a means to stabilise any sized area of hillside or riverbank and thereby prevent erosion.

In one preferred embodiment, two or more frameworks may be connected together in a laterally aligned chain by joining adjacent sidewalls of the frameworks such that the two retention spaces are in a side-by-side relationship, e.g. spaced from each other in a direction substantially parallel to the connecting walls thereof.

The frameworks may thus be arranged in laterally or longitudinally to form a chain or in a network depending upon the intended usage.

According to another preferred embodiment of the present invention, there is provided a liquid filtration and/or treatment system, including a plurality of frameworks chained or networked together as hereinbefore described.

Preferably, the frameworks of the liquid filtration system are arranged in a substantially chained arrangement with respect to the liquid flow direction, each subsequent framework in the direction of flow having the same sized or smaller apertures to filter either the same sized or substantially smaller particulate from the liquid. The chain of frameworks may then act to sequentially separate ever decreasing sizes of particulate from the liquid flow.

Preferably, the upper, or first framework forms a first retention space, configured to capture the largest solid matter contained within the liquid flow, the second framework is then configured to capture any solid matter overflow or discharge from the first framework, each subsequent retention space being configured to further filter solid matter from the liquid flow. The lower most retention space may be filled with additional matter to improve the filtration of the liquid flow. In a preferred embodiment one or more of the endmost retention spaces in the chain may contain material for further altering the characteristics (i.e. treating) of the liquid. For example, one retention space may include a treatment material such as slag for the removal of phosphates; another retention space may contain a treatment material such as dolomite to lower the pH of the liquid.

In another preferred embodiment, one or more frameworks may be mounted on a surface substantially perpendicular to a liquid flow, for example, upon the sides of a channel or riverbank such that the sidewalls of the framework are upstream of the connecting wall. The connecting wall thereby restricting the flow of water near the surface on which the framework is attached reducing erosion of said surface and promoting deposition of particulate downstream of the connecting wall due to the reduced flow rate.

In another embodiment, a framework may be formed by three sidewalls connected to two connecting walls, wherein one said sidewall is located between the other two sidewalls to partition the framework into two retention spaces, the partitioning sidewall being connected to both said connecting walls. Such a composite framework may be useful in reducing the number of components needed, e.g. only three sidewalls are required in comparison to the four sidewalls used where two frameworks are joined together, side by side.

According to yet another aspect of the present invention there is provided a method of retaining particulate to a work surface inclined with respect to horizontal, the method including:

- securing a framework or a particulate retention system, substantially as hereinbefore described, to the work surface. Preferably, after securing the framework to the work surface, particulate is deposited in the retention space of the framework.

The aforementioned framework and method provides a means to convert an inclined or vertical surface, to a surface with a shallower gradient, while at the same time providing a retention space for retaining particulate.

According to yet another aspect of the present invention there is provided a pathway- framework for constructing a pathway or the like on a work surface, the pathway- framework including:

- two sidewalls releasably attached to a connecting wall extending between the sidewalls, a retention space for retaining particulate defined between the walls, and

characterised in that an edge of at least one said sidewall has a plurality of flanges protruding toward the retention space.

Preferably each flange is spaced from adjacent flanges such that the sidewall can be curved concave with respect to the retention space without the flanges contacting each other.

Preferably, each flange has an edge opposing an edge of an adjacent flange, and wherein the portions of said flange edges distal to the sidewalls are spaced apart from each other at a greater distance than the portions of the edges proximate the sidewalls.

As the flanges are separate from each other they allow the sidewalls to be curved to bring the edges of each flange closer together, the pathway- framework may thus provide curved sidewalls with an upper flat edge formed by the flanges. The flanges also assist in retaining the particulate within the retention space.

In many applications it may be inconvenient to have a pathway with a narrow or 'sharp upper edge, e.g. animals, people or vehicles may travel over the edge and damage their feet or wheels on the sharp edge. The aforementioned pathway- framework can thus be used to reduce the risk of damage to animal's feet or the like.

Preferably, at least a portion of a said sidewall is capable of being bent about an axis co-planar with a said flange to thus permit the sidewall to be curved or bent to follow the contours of the work surface.

Preferably, the portion of sidewall capable of being bent includes a weakened area in the plane of the wall.

Preferably, the weakened area is a line extending in the plane of the wall.

Preferably the weakened area is formed by a perforation, indent, slot, or other weakening in the wall.

In a further embodiment, at least two of the frameworks are joined together, the two sidewalls of a first framework being attached to the connecting wall and/or sidewalls of a second framework.

Preferably, the sidewalls of the first pathway- framework may be connected to the sidewalls of the second framework via the connecting wall, e.g. in one preferred embodiment, the sidewalls of frameworks to be joined together include an aperture proximal to the ends to be joined, each aperture capable of receiving a corresponding protrusion provided on the connecting wall. Thus, the connecting wall not only acts as a 'cross-bracing' member and wall for retaining particulate, but also acts as a 'cross- joining' member for joining frameworks together. Furthermore, where the framework is used as a concrete formwork, the connecting wall may also act as an expansion 'gap'.

Preferably, the connection between the first and second frameworks is configured such that the first and second frameworks are movable (e.g. pivotable) relative to each other.

A 'chain' of frameworks may thus be used to form a pathway over a surface. Each framework retention space forms a particulate retention cell that when filled with particulate can form a solid pathway that potentially will not deteriorate with water induced erosion.

Preferably, the framework is constructed from galvanised steel.

Preferably, the front-wall has one or more apertures therein and more preferably a plurality of apertures.

Preferably, a said sidewall has one or more apertures therein.

According to yet another aspect of the present invention there is provided a method of constructing a pathway or the like, the method including:

- securing a plurality of frameworks and/or pathway- frameworks, both substantially as hereinbefore described, to a surface on which the pathway is to be formed, and

- depositing particulate within the retention space of the framework. _.

Preferably, the particulate may be soil, sand, rock or a mixture thereof. However the exact composition of the particulate retained in a retention space should not be seen as limiting.

It should be appreciated that the sidewalls and/or connecting wall as aforementioned may be formed as box members, thin sheets of material or solid members without departing from the scope of the present invention.

The aforementioned 'pathway framework' may thus provide a means for constructing a pathway with improved particulate retention within each retention space of the frameworks.

According to one aspect of the present invention there is provided a framework system wherein the framework system is constructed from a chain or mesh of two or more frameworks wherein each framework includes:

^■ two sidewalls having first and second opposing edges, the second edge configured to rest on the work surface; and

^■ a connecting wall joining the sidewalls and extending there between, the sidewalls and connecting wall defining a retention space there between for retaining the particulate, wherein the sidewalls are tapered such that the first edge of each sidewall is inclined, with respect to the second edge, to taper away from the connecting wall,

A method of treating a liquid characterised by the steps of:

- causing a liquid to be treated to pass through/over a plurality of frameworks each framework defining a retention space; - wherein each retention space or group of retention spaces is/are configured to remove matter in the liquid or otherwise alter the composition of the liquid.

Preferably, the retention space or group of retention spaces contains apertures of a size to capture unwanted matter from the liquid to be treated and/or at least one treatment material which can remove unwanted matter from the liquid to be treated.

Preferably the frameworks used with the method of treatment may be substantially as described herein.

Preferably one or more frameworks are connected together to effectively form a chain of frameworks which spans along a channel or other path along which a liquid flows, such that the flow of liquid must pass through or over the chained retention frameworks, forming a liquid treatment system being constructed from:

- a chain of two or more frameworks, each including:

^■ two sidewalls having first and second opposing edges, the second edge configured to rest on the work surface; and

^■ a connecting wall connected to the sidewalls and spanning the width of the channel or path along which liquid travels, such that liquid must pass through or over the connecting wall in order to pass the retention space.

Preferably each subsequent retention space or group of retention spaces include(s) apertures to retain either the same size or smaller particulate than that of the preceding framework; and wherein downstream retention spaces in the. chain may include additional or different treatment material for further alteration of the characteristics of the liquid.

A method of helping prevent erosion from occurring on the surfaces of uni-directional flow waterways characterised by the steps of:

a) creating a network of connected frameworks along x and y axes over the erosion prone surface of the waterway;

b) fixing the network of frameworks to the erosion prone surface;

c) positioning said network of frameworks so that one sidewall is upstream of the connecting wall(s);

wherein the frameworks include:

- two sidewalls having first and second opposing edges, the second edge configured to rest on the work surface; and

- a connecting wall joining to the sidewalls and extending there between, the sidewalls and connecting wall defining a retention space there between for retaining the particulate,

wherein the first edge of each sidewall is inclined, with respect to the second edge, to taper away from the connecting wall.

In preferred embodiments the longitudinal axis of the upstream side arm of the framework may be positioned to be angled in substantially the same general direction as the flow direction of the waterway. Most preferably, the angle of the longitudinal axis of the upstream sidewall of the framework relative to the flow direction of the waterway may be substantially between 30° - 50°.

According to yet another aspect of the present invention there is provided a method of constructing a. stepped pathway or the like on a sloped surface, the method including:

- hanging a plurality of chained frameworks, substantially as hereinbefore described, to a surface on which the stepped pathway is to be formed, and

- depositing particulate within the retention spaces of the frameworks.

Preferably the framework may be hung on a surface via pegs, spikes or the like.

BRIEF DESCRIPTION OF DRAWINGS

Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which:

Figure 1a shows a pictorial representation of a portion of a longitudinally aligned chain of frameworks according to one preferred embodiment of the present invention;

Figure 1 b shows a pictorial representation of a pathway using the frameworks of figure 1a together with a pathway- framework configured to include a corner according to another preferred embodiment of the present invention; Figures 2a and 2b respectively show a side elevation and plan view of a sidewall of one embodiment of the framework shown in figure 1 ;

Figure 3a and 3b shows a front elevation and profile view of a connecting wall of the framework shown in figure 1 ;

Figure 4 shows a side elevation of the framework on an inclined work surface;

Figure 5 shows an enlarged partial side elevation of a sidewall of a framework;

Figure 6 shows a profile view of a sidewall of a framework;

Figures 7a, 7b and 7c shows a front elevation and profile view of a cross bracing wall of a framework;

Figure 8 shows a pictorial representation of a particlulate retention system in another preferred embodiment of the present invention, the particulate retention system formed from a network or mesh of frameworks to protect the bank of a river from erosion;

Figure 9 shows a plan view of the erosion prevention system which helps prevent erosion from occurring on the surfaces of uni-directional flow waterways around and below the waterline as shown in figure 8 in accordance with one preferred embodiment of the present invention; Figure 10 shows a pictorial plan representation of a liquid filtration/treatment system in another preferred embodiment of the present invention, the frameworks being chained sequentially; and

Figure 11 shows an end on sectional view of the liquid filtration/treatment system shown in figure 10.

BEST MODES FOR CARRYING OUT THE INVENTION

With respect to figure 1 there is shown a partial a chain of frameworks 1 which has two longitudinally connected frameworks 1000 made of galvanised steel. This chain of frameworks 1 can be used for retaining and stabilising particulate as part of a particulate retention system or as part of a stepped path on a sloped surface such as a hill. Figure 4 shows side view of one of the frameworks 1000 in the chain 1.

The framework 1000 is configured to retain particulate in the form of soil 6 to a work surface in the form of a hill 5.

The framework 1000 has two sidewalls 100 attached to a connecting wall 200 extending between the sidewalls 100.

Retention spaces 8 for retaining the particulate 6 are respectively defined between the walls 100,200 of the frameworks 1000.

As shown in figure 2 and 6, the sidewalls 100 are tapered such that the first edge 101 of each sidewall 100 is inclined with respect to the second edge 102, from a 'small' end 103 distal to the connecting wall 200 (not shown in figure 2). The angle of the first edge 101 may vary depending on the steepness of the surface on which the second edge

102 rests; this is most clearly shown by the dashed lines in figure 6.

The framework 1000 has two sidewalls 100, each with first 101 and second 102 opposing edges. The second edge 102 is configured to rest substantially parallel to an inclined hillside 5.

The first edge 101 of the sidewalls 100 and upper edge 201 of the connecting wall 200 define an upper boundary for soil 6 deposited in the retention space 8.

The soil 6 can thus be collected in the retention space 8 to a greater depth adjacent the connecting wall 200, than at the opposing end 103. Therefore, when the framework 1000 is located on an inclined work surface 5, the retention space 8, when filled with particulate 6, will create an upper surface 7 at a relatively shallower gradient than that of the hillside 5. Thus, the framework 1000 can be used to convert a steep hill side 5 to a relatively shallower surface 7 to thereby enhance the stability of the hillside 5 and resistance to erosion. Figure 6 illustrates how the relationship between the angle of the first 101 and second 102 opposing edges might vary depending upon the slope (not shown in figure 6) on which the framework 1000 is attached.

As shown more clearly in figures 2 and 3, the sidewalls 100 are attached to the connecting wall 200 via the insertion of hooked tabs 105 through slots 203 in the connecting wall 200.

The hooked tabs 105 are pre-formed into shape and the connecting wall 200 is located such that slots 203 are positioned onto the hooked tabs 105. The connecting wall 200 is retained in place by the weight of particulate 6 in the retention space 8 bearing on the rear of the connecting wall 200, holding the slots 203 in the connecting wall 200 against the tabs 105 of the sidewalls 100.

The use of hooked tabs 105 provides for quick and easy assembling of the framework 4, which can be important in many applications in remote locations or on surfaces that are steep, muddy, slippery or otherwise difficult to access.

As the hooked tabs 105 slot into the apertures 203 in a 'loose-fit' arrangement, (e.g. allowing some relative movement of connected frameworks 1000) the frameworks 1000 can be linked together such that the second edges 102 are not required to be co- linear, allowing the retention system 1 to follow the contours of the surface 5 without the necessary surface modification (e.g. flattening) necessary to implement the prior art barrier systems.

The sidewalls 100 also include an attachment provided in the form of a 'securement' flange 107 which has an aperture 108 through which a peg is passed and driven into the work surface 5 to secure the framework 1000 to the work surface 5. The use of pegs 114 allows the framework 1000 to be 'hung' via the pegs 114 from steep surfaces, in contrast to prior art terracing which involves modification of the surface or embedding of walls. The framework 1000 can thus be secured to a range of surface types and gradients.

The connecting wall 200, when connected to the sidewalls 100, is backwardly inclined at an angle θ with respect to the sidewall 100 second edges 102. 'Reverse' inclining the connecting wall 200 toward the retention space 8 reduces the effective torque placed on the connecting wall 200 about the connection to the sidewalls 100 by the weight of particulate 6 bearing on the connecting wall 200. The front-wall also has a plurality of apertures 205 that allow liquid and/or particulate 6 small enough to pass through the apertures 205 to pass from the retention space 8. Draining liquid from the retention space 8 is useful to reduce the liquid content that could potentially mobilise the particulate 6 by carrying the particulate 6 over the upper edges 101 and 201 of the framework 1000 out of the retention space 8, the uncontrolled fluid flow could then cause erosion of the surrounding surface 5.

The apertures 205 are sized and located to control the flow of water and particulate 6 from the retention space 8 to ensure the water content does not exceed that suitable for promoting plant growth.

The apertures 205 are located above the lower edges 102, 202 so that the framework 1000 retains enough water to promote plant growth. This water retention can be useful for re-vegetation on steep, arid or rocky surfaces.

As best shown in figures 3b and 6, the connecting wall 200, is formed from folded galvanised steel shaped with an upper 201 and lower 202 flanges that each extend along upper and lower edges of the connecting wall 200. The upper flange 201 protrudes toward the retention space 8 to assist in retaining the particulate 6 within the retention space 8.

As is best shown in figure 5 the lower flange 202 is provided to facilitate secure fitment of the connecting wall 200 inner slots 204 (not shown in figure 5) to the sidewall 100 tabs 106.

It should be appreciated that while not shown in the drawings, the sidewalls 100 may also have flanges similar to that of the connecting wall 200 as described above. The method of attaching the connecting wall 200 to the sidewalls 100 is now described with reference to figures 2, 3 and 5.

The connecting wall 200 has 'outer' slots 203 that receive hooked tabs 105 on the larger end 104 of the sidewall 100. This larger end 104 has an edge 109 inclined with respect to the second edge 102. The connecting wall 200 can thus be secured to the sidewalls 100 at an inclined angle θ with respect to the second edge.

The walls 100 and 200 are connected by hooked tabs 105 that are pre-bent at right angles to the sidewall 100 and then folded back toward the smaller end 103 of the sidewall 100 to form a hook feature. The connecting wall 200 is then positioned so hooked tabs 105 hook though slots 203.

The connecting wall 200 also has 'inner' slots 204 that receive tabs 106 on the smaller end 103 of the sidewalls 100. The sidewalls 100 include an inclined edge 110 inclined with respect to the second edge 102 at the same angle θ as the other end 104.

The connecting wall 200 can thus act as a medial interface between two sets of sidewalls 100, whereby the sidewalls 100 forming a retention space 8 with the medial connecting wall 200 are connected via hooked tabs 105 through slots 203 and the sidewalls 100 to the front of the connecting wall 200 are connected with tabs 106 through slots 204.

Attaching the tabs 106 of the smaller end 103 of the sidewall 100 to the inner slots 204 of the connecting wall 200 and the larger end 104 of another framework 1000 to respective outer slots 203, ensures that not only is the 'depth' of the retention space 8 tapered, but also the width, i.e. the width is tapered to a wider part at the connecting wall 200. It should be appreciated that the chain of frameworks 1 and/or multiple chains of frameworks 1 can be also be positioned and/or joined in 'parallel' where required to create a network.

The frameworks 1000 can also be arranged in a network over a hillside 5 to reduce the effective gradient of the hillside and assist in retaining soil 6 - refer figure 8 discussed below.

As shown in figure 1 b.there is provided a pathway generally indicated by arrow 2000. The pathway 2000 has frameworks 1000 (of which only one is shown) together with pathway- frameworks 2001. For ease of reference only the sidewalls and connecting sidewalls of the pathway - framework 2001 will generally be referred to with the same reference numerals as used for the framework 1000 as they both retain particulate and connect to one another via tabs (not shown). The pathway- framework 2001 differs from the framework 1000 in that the sidewalls 100 have parallel upper 201 and lower edges 202 which are not tapered like the upper edge 101 and lower edge 102 of the framework side wall 100.

The upper edges 101, 201 of each of the walls 100 includes an upper edge flange 112, 208, 201 , being either a single flange 208 extending the length of said edge 101 , or a plurality of flanges 112 spaced along the length of said edge, the flanges protruding toward the retention space 8. Each of the plurality of flanges 112 is spaced from adjacent flanges 112 such that the sidewall 100 can be curved concave with respect to the retention space 8 without the flanges 112 contacting each other and restricting curvature.

A slot or notched space 113 is provided between each flange 112. The flanges 112 are tapered so that as the sidewalls 100 are bent into a curve, the edges of adjacent flanges 112 are brought closer together to provide curved sidewalls 100 with an upper flat edge formed by the flanges 112. The flanges 112 also assist in retaining the particulate 6 within the retention space 8.

Drainage apertures 205 are formed in the sidewalls 100 and act to assist in draining liquid from lateral sections of the retention space 8.

Flanges 107 are provided on a lower edge 102 of the sidewalls 100 for facilitating securement of the framework 1000 to the surface 5 via pegs 114, as shown in figure 1.

The pathway -framework 2001 may also be provided with cross-bracing members 206 that extend between sidewalls 100. The cross-bracing members 206 (as best shown in figure 1 , and 7) are connected between sidewalls 100 by tabs 207 inserted through slots 113 in the sidewalls 100. The tabs 207 are then bent at right angles. The cross- bracing 206 also has drainage apertures (not shown) for facilitating drainage of liquid there through.

The cross-bracing 206 has an upper flange 111 which serves the same function as the flanges 201 on the connecting wall 200.

The cross-bracing 206 may thus serve a similar function to the connecting wall 200 and can thus be considered substantially the same as one another.

The sidewall 100 may have slots 113 at a midpoint and at one end for respectively receiving the tabs 207 of the cross-bracing 206 member.

Once the particulate retention system 1 is assembled, the retention spaces 8 are filled with particulate 6, e.g. soil, and thus provide a far more stable surface than the corresponding hillside 5 on which it is placed. As shown in Figures 8 and 9, in another preferred embodiment, particulate retention and erosion prevention systems may be used in prevention of erosion of river and levee banks 14.

By locating the frameworks 1000 in a 'network' of frameworks 3000 on the face of a river or levee bank 14 the system can protect the bank from slippage and erosion.

Around and below the waterline (refer Figure 9) there is provided an erosion prevention system 4000 for a uni-directional flow waterway. In the system 4000 the frameworks 1000 are positioned with the sidewalls having their first and second edges 101 and 102 in a horizontal plane whereas the connecting wall 200 has its longitudinal axis located in a vertical plane.

The frameworks 100 are also positioned so the connecting walls 200 are located downstream of the sidewalls 100 and are angled with respect to the general direction of the predominant water flow, as indicated by arrow(s) A. In use, the flow rate of water passing over the connecting wall 200 upper flange 201 increases, whilst the flow rate through the apertures 205 in the connecting wall 200 is reduced. This lowers the flow rate and pressure immediately adjacent the river bank or levee face, reducing erosion therefrom, whilst at the same time creating a turbulent vortex action B in the water immediately downstream of the connecting wall 200. This has the effect of freeing sediment suspended in the water flow, which will then be deposited in the retention space downstream of said connecting wall 8, actively accumulating new material to rebuild the river or levee bank. As shown in Figures 10 and 11 , another preferred embodiment of the present invention is for treating liquid. One such application of the system controlling the discharge of material into waterways and the like. A series of cascaded frameworks 1000 are positioned in and configured to substantially span the width of a culvert or drainage channel 14 or the like, such that any material flowing into the channel, shown by arrow A, must pass through each frameworks 1000 faceplate 200 apertures 205.

In preferred embodiments a first retention space 8 is configured with large apertures 205 in order to retain large solid matter, such as grass or sticks, subsequent retention spaces 8, of which there could be any number, are configured to retain subsequently smaller solid matter, and have correspondingly smaller apertures 205.

In preferred embodiments, retention spaces 8 may also be filled with additional filter material 10, 11 to aid in the separation of solid matter from the liquid flow, or a filter material may be added to separate specific substances from or alter the composition of the liquid flow, as an example, the end most retention spaces 8a, 8b may contain material such as slag 10 for filtering of phosphates, or dolomite 11 for reducing the pH of the water flow. The filtered liquid, shown leaving the filtration system, as shown by arrow B, may then pass safely into waterways without risk of eutrification or contamination of bodies of water fed from said waterway.

In preferred embodiments, removal of accumulated solid matter from each of the retention spaces 8 for suitable disposal or recycling is possible, Figure 11 illustrates that removal of the channel cover 12 allows for such removal of accumulated matter.

As will be evident from the aforementioned discussion, the particulate retention system 1 and/or frameworks 1000, have a wide range of applications in retaining and stabilising particulate 6. The following description provides brief examples of particular uses for which the present invention has application, though these examples should not be seen to be limiting. Riverbank erosion and slumping occurs predominantly due to the weight and dislodgement of soil due to animal traffic or the erosion and wear by the water on the bank.

Erosion and slumping caused by animals can be reduced by locating an array of frameworks 1000 in 'parallel' so that the connecting walls 200 of each framework 1000 face the river and the array extends along the vulnerable stretch of riverbank around and below the waterline. The gradient of the riverbank is thus reduced while the frameworks 1000 retain any soil pushed toward the river by the animals.

Erosion caused by river water flow can be reduced by locating the frameworks 1000 in a array with the longitudinal axis of the connecting walls 200 generally to the predominant water flow - refer figures 8 and 9. The disruption in flow caused by the connecting walls 200 thus lowers the liquid pressure at the face 9 and sediment carried in the water will be deposited in the retention space.

The 'slumping' or collapse of inclined roadsides is a common problem which can be addressed by locating the frameworks 1000 along the surface of the roadside to form a more 'rigid' and stable roadside while free-draining the soil to inhibit water-induced slumping.

The frameworks 1000, can also be used to reduce liquid flow from an outlet, e.g. from a dam, by locating the connecting wall 200, 'downstream' of the liquid flow.

The framework 1000 can be used to reduce the risk of culverts and the like being blocked by locating frameworks 1000 in series upstream of the culvert to reduce the velocity of water and collect particulate 6 in the water. This arrangement may also be used in reducing liquid flow along embankments, levees and the like to reduce the water velocity and therefore level of erosion.

The frameworks 1000 can also be positioned around the shores of lakes, water supplies and conservation areas to collect and retain sedimentation, liquidised minerals and/or chemicals that may be washed from the surrounding area into the water. The retention spaces 8 can be planted with soil and grass, sedges and other plants to stabilise the soil and filter the minerals, nitrogenous particles and other potentially harmful chemicals from the water flowing off the surrounding land. It will be appreciated that for optimum effect, the frameworks 1000 may be located to cover an area between anticipated high and low water, inclusive of lee shore wave action.

The frameworks 1000 can be used to stabilise gravel beds in streams and the like for re-habitation for aquatic species of insects, fish or invertebrates. As gravel builds up in the retention space 8, the frameworks 1000 may be progressively lifted and repositioned on top of the previously collected gravel to provide a resultant gravel bed of any required depth.

It will also be appreciated that the frameworks 1000 may also be used as a formwork for bedding concrete.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope of the appended claims.