Method and system of stabilising a landform

Abstract

Known methods for the stabilisation of landforms include the installation of rock bolts. However, such methods may provide a limited amount of support to the landform, and points of failure may merely be translated back from an exterior surface of the landform, adjacent to where the rock bolts terminate. The present invention enables an underground bore (50) to be drilled from a remote location (40), through which a line (70) is passed. The line is connected to a barrier (20) adjacent to an exterior surface (10) of the landform, and tensioned by pulling the line through the bore. This enables the transfer of load from the exterior surface, through the underlying geology and to the remote location, thereby providing adequate stabilisation of the landform with minimal points of failure.

Description

METHOD AND SYSTEM OF STABILISING A LANDFORM

[0001] The present invention relates generally to a method and system of stabilising a landform and finds particular, although not exclusive, utility in stabilising a cliff face or an embankment.

[0002] Unstable landforms can be problematic for any desired activity and / or construction adjacent to, or in the proximity of, the landform. This problem can be exacerbated when the landform has an incline, in particular when the landform has a steep, or substantially vertical, surface. Examples of commonly unstable landforms include cliffs and embankments. Another factor affecting the instability of the landform is the composition of the underlying geology at or adjacent to its exterior surface. Examples of desired activity or construction adjacent to a landform include the construction and maintenance of transport links such as railways and roads.

[0003] Known methods and systems for the stabilisation of landforms include the installation of rock bolts. Typically, boreholes are drilled into an exterior surface of a landform, and rock bolts are inserted into the boreholes. In combination with a wire mesh placed over the surface, the rock bolts transfer loads from the exterior surface into the load bearing solid geology behind the surface. The drawbacks of such techniques include a limited amount of support to the surface, and that the points of failure of the landform may merely be translated from the surface further back into the landform, adjacent to where the rock bolts terminate. Therefore, such techniques may not be suitable for stabilising landforms with high instability and / or steep gradients.

[0004] In a first aspect, the present invention provides a method of stabilising a landform, the method comprising the steps of: arranging a barrier adjacent to an exterior surface of a landform; drilling an underground bore between a remote location and the exterior surface; passing a line through the bore; attaching a first end of the line to the barrier; and tensioning the line by pulling the line through the bore.

[0005] In this way, a landform may be stabilised in a manner that significantly reduces, or substantially prevents, ground movement and / or slippage of the exterior surface of the landform. The tensioned line may connect the barrier with a remote location, and thereby transfer the load from the exterior surface through the underlying geology and to the remote location. Accordingly, the entirety of the underlying geology adjacent to the exterior surface may be stabilised, irrespective of the gradient of the exterior surface and / or the stability of the underlying geology.

[0006] A landform may comprise a natural or anthropogenic land feature, for example a cliff, an embankment, a tunnel, a valley, a ridge, or a hill. An exterior surface of the landform may be part or whole of an outward-facing surface of the landform.

[0007] Stabilising may comprise transferring loads from the exterior surface of the landform to a remote location and / or to the underlying geology. Alternatively or additionally, stabilising may comprise deploying material and / or equipment into the landform to reinforce areas of geological failure.

[0008] The barrier may comprise a mesh, a membrane, a net, a coating and / or a textile. In particular, the barrier may comprise a wire mesh and / or spray applied concrete or mortar. The barrier may comprise a plurality of the same type of barrier and / or different types of barriers.

[0009] In this way, the type and extent of the barrier may be adapted according to the landform and / or underlying geology.

[0010] Adjacent to an exterior surface of a landform may comprise immediately adjacent to the exterior surface, that is, in contact with the exterior surface. Alternatively or additionally, adjacent to an exterior surface of a landform may comprise next to, but spaced from the exterior surface.

[0011] Drilling may comprise directional boring, for example Horizontal Directional Drilling (HDD) or forms of directional drilling used in the oil & gas industry. HDD is capable of boring suitably accurate holes up to only ~800m long with diameters only between 100mm and 1200mm. Alternatively, directional drilling is used in the oil & gas industry, and enables much longer holes to be bored.

[0012] The bore may have a diameter of between 80mm and 1200mm; the bore may have a length of at least 2m, at least 50m, at least 100m, at least 200m, at least 500m or more.

[0013] A plurality of bores may be drilled through the underlying geology, between the remote location and the exterior surface. For example, between 2 and 200 bores may be drilled, in particular between 10 and 50 bores may be drilled, more particularly 25 bores may be drilled. A longitudinal axis of each of the plurality of bores may be substantially parallel to one another, for example where an opening of each bore lies in a two-dimensional or three-dimensional array. Alternatively or additionally, a longitudinal axis of each of the plurality of bores may diverge or converge from one another, dependent on the arrangement of the opening of the bores, the geometry of the landform and / or the composition of the underlying geology.

[0014] Drilling may be carried out from the remote location towards the exterior surface. In this way, machinery and equipment may be substantially absent from the landform to be stabilised, to reduce risk of damage thereto, and to minimise interruption to adjacent transport links. Alternatively or additionally, drilling may be carried out from the exterior surface towards the remote location.

[0015] The remote location may comprise a location spaced apart from the exterior surface. As will be appreciated, the remoteness of the location may scale in proportion to the size of the landform. The remote location may be spaced from the exterior surface by at least 2m, at least 50m, at least 100m, at least 200m, at least 500m or more. The remote location may comprise a single anchor point, that is, a stable location capable of bearing significant loads without failure. Alternatively or additionally, the remote location may comprise a plurality of anchor points arranged at multiple locations, for example in a two-dimensional array and / or a three-dimension array. The anchor point(s) may comprise pilings. The remote location may comprise foundations and / or other structures to reinforce the remote location and / or integrate it into the underlying geology.

[0016] The line may comprise a cable, chain and / or other suitable line; for example, the line may be strong under tension and / or substantially inextensible, but may be flexible. Alternatively, the line may comprise a shaft, rod and / or other suitable line; for example, the line may be strong under compression and / or substantially uncompressible, and / or the line may be substantially rigid.

[0017] The line may have an exterior diameter less than the interior diameter of the bore.

[0018] Attaching a first end of the line to the barrier may comprise inserting the line through an aperture in the barrier and securing the line via tying, crimping and / or welding. Alternatively or additionally, attaching a first end of the line to the barrier may comprise arranging attachment means adjacent to the line and the barrier. An attachment means may comprise bolts, screws and / or adhesive.

[0019] Pulling the line through the bore may comprise pulling a second end of the line in a direction towards the remote location. Alternatively or additionally, pulling the line through the bore may comprise pulling the line from one or more points along a longitudinal axis of the line towards the remote location.

[0020] The method may further comprise the step of lining a first length of the bore with a pipe.

[0021] In this way, the integrity of the bore may be maintained to facilitate the passing of the line through the bore. In addition, the lining of the bore with the pipe may improve the integrity of the underlying geology, thereby aiding in the stabilisation of the landform.

[0022] Lining the bore with a pipe may comprise deploying a pipe pulling device into the bore to pull pipe along the bore in a direction away from the remote location. A pipe deploying apparatus may be disposed on the line to line the bore with a pipe.

[0023] A first length of the bore may be the entire length of the bore.

[0024] Passing a line through the bore may comprise passing a line through the pipe, before, after or during the step of lining the bore with a pipe.

[0025] The method may further comprise the step of anchoring the pipe into the underlying geology.

[0026] In this way, the pipe may provide a secure structure for the cables to pass through.

[0027] The step of anchoring the pipe into the underlying geology may comprise deployment of material and / or equipment into the underlying geology.

[0028] Deployment of equipment may comprise passing drilling equipment, or some other form of equipment for making a hole, down the bore; and / or using the equipment to make at least one hole at least partially through the pipe. The hole(s) may be made by drilling, piercing, milling, punching, gouging, cutting, and / or any other suitable method. In this way, material and / or equipment may be deployed through the hole in the pipe to anchor the pipe into the underlying geology.

[0029] The equipment may be configured to make the hole at most only partially through the pipe. In this way, exterior material and / or water may be prevented from entering the bore in an uncontrolled manner. In particular, the hole(s) may extend almost all the way through a wall of the pipe (e.g. to less than 2mm, in particular less than 1mm from the outer surface of the pipe wall). In alternative arrangements, the drill / device may be configured to make the hole entirely through the pipe, and may even be configured to drill, etc. into the surrounding geology. The pipe may include the holes prior to insertion into the bore.

[0030] For example, the pipe may be pre-perforated. In this way, time and cost on site may be avoided in situations in which the underlying geology is well understood. The pre-perforated liner may comprise an outer sleeve that covers the perforations; in this way, exterior material and / or water may be prevented from entering the bore in an uncontrolled manner.

[0031] Deploying material and / or equipment through the hole may comprise extending a probe through the hole such that it passes outside the pipe. In some cases, the probe may project into the surrounding geology. The probe may be configured to punch through the pipe wall; in particular, the probe may be configured to punch through either the small amount of pipe wall remaining after drilling etc., or the sleeve of a pre-perforated pipe. The probe may comprise a needle. The needle may be configured to permit material flow therethrough. Alternatively, the needle may be configured to retract and a material may be injected directly through the hole. The pipe and / or liner may comprise a plastics material, as is well understood in the art.

[0032] Deployment of equipment may comprise passing an integrated drilling and injection device down the pipe. The device may be driven into the pipe and / or underlying geology to a desired depth, after which material and / or fluid may be injected into the underlying geology.

[0033] Deployment of equipment may comprise the insertion of bolts, screws and / or clamps into the underlying geology.

[0034] Deployment of material into the underlying geology may comprise the injection of chemical stabiliser, for instance via chemical delivery nozzles (e.g. within telescopic arms). The amount and type of stabiliser used will be determined by the geology to be stabilised and can be controlled as required, and may comprise cement or any other suitable material such as microcements, mineral grouts (known as colloidal silica), water sensitive polyurethanes (rapid reacting foaming resin to combat water ingress), quick reacting and non-water sensitive polyurea silicate systems (expanding foam for void filling), acrylic resins, jet grouting viz. the in situ construction of solidified ground to a designed characteristic; often known as Soilcrete (RTM), etc.

[0035] The step of lining the bore with a pipe may comprise driving the pipe into the bore. In this way, a device may be deployed from the remote location to drive the pipe into the bore, thereby avoiding the requirement to deploy addition equipment down the bore to line the bore with the pipe. Driving the pipe into the bore may comprise forcing and / or ramming the pipe along the bore, to overcome friction forces between an exterior wall of the pipe and an interior of the bore.

[0036] A second length of the bore adjacent to the barrier may not be lined with a pipe. In other words, a first length of the bore lined with a pipe may stop short of the exterior surface of the landform and / or the barrier. The second length of the bore may be between 2m and 50m, in particular between 5m and 25m, more particularly approximately 10m.

[0037] In this way, the structural integrity of the underlying geology immediately adjacent to the exterior surface may be optimally maintained.

[0038] The method may further comprise the step of deploying material into the pipe. In this way, the line may be further secured within the pipe via contact with the material along a length of the cable.

[0039] Material deployed into the pipe may comprise cement or any other suitable material such as microcements, mineral grouts (known as colloidal silica), water, sensitive polyurethanes (rapid reacting foaming resin to combat water ingress), quick reacting and non-water sensitive polyurea silicate systems (expanding foam for void filling), acrylic resins, jet grouting viz. the in situ construction of solidified ground to a designed characteristic; often known as Soilcrete (RTM), etc.

[0040] The method may further comprise the step of attaching a second end of the line adjacent to the remote location.

[0041] In this way, the transfer of load between the first end and the second end of the line may be maintained.

[0042] Tensioning the line may comprise pulling the line through the bore from the remote location; however, it is conceivable that the line could be pulled through the bore from a point within the bore, and / or from a location outside the bore and spaced from the remote location. The method may further comprise the step of monitoring tension and / or movement of the line.

[0043] In this way, the stability of the landform may be monitored.

[0044] The method may further comprise the step of stabilising the underlying geology.

[0045] Stabilisation may be via ground freezing techniques, for instance by coolant pumped through the pipe and potentially exiting the pipe through perforations. Freezing techniques may be temporary.

[0046] As an alternative, permanent stabilisation may be achieved by injecting chemical stabiliser, for instance via chemical delivery nozzles (e.g. within telescopic arms). The amount and type of stabiliser used will be determined by the geology to be stabilised and can be controlled as required, and may comprise cement or any other suitable material such as microcements, mineral grouts (known as colloidal silica), water sensitive polyurethanes (rapid reacting foaming resin to combat water ingress), quick reacting and non-water sensitive polyurea silicate systems (expanding foam for void filling), acrylic resins, jet grouting viz. the in situ construction of solidified ground to a designed characteristic; often known as Soilcrete (RTM), etc.

[0047]

[0048] In a second aspect, the invention provides a system for carrying out the method of stabilising a landform according to the first aspect, the system comprising: a barrier for arranging adjacent to an exterior surface of a landform; directional drilling apparatus for drilling an underground bore through underlying geology; a line for passing through the bore; attachment means for attaching a first end of the line to the barrier; and tensioning means for pulling the line through the bore.

[0049] The above and other characteristics, features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. This description is given for the sake of example only, without limiting the scope of the invention. The reference figures quoted below refer to the attached drawings.

[0050] is a partially cutaway perspective view of a system for stabilising a cliff face.

[0051] is a partially cutaway perspective view of a system for stabilising embankments.

[0052] is a perspective cross-sectional view of a system for stabilising an embankment under a road.

[0053] is a detailed partially cutaway view of ground treatment being carried out through a pair of pipes.

[0054] The present invention will be described with respect to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. Each drawing may not include all of the features of the invention and therefore should not necessarily be considered to be an embodiment of the invention. In the drawings, the size of some of the elements may be exaggerated and not drawn to scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

[0055] Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that operation is capable in other sequences than described or illustrated herein. Likewise, method steps described or claimed in a particular sequence may be understood to operate in a different sequence.

[0056] Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that operation is capable in other orientations than described or illustrated herein.

[0057] It is to be noticed that the term “comprising”, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression “a device comprising means A and B” should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

[0058] Reference throughout this specification to “an embodiment” or “an aspect” means that a particular feature, structure or characteristic described in connection with the embodiment or aspect is included in at least one embodiment or aspect of the present invention. Thus, appearances of the phrases “in one embodiment”, “in an embodiment”, or “in an aspect” in various places throughout this specification are not necessarily all referring to the same embodiment or aspect, but may refer to different embodiments or aspects. Furthermore, the particular features, structures or characteristics of any one embodiment or aspect of the invention may be combined in any suitable manner with any other particular feature, structure or characteristic of another embodiment or aspect of the invention, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments or aspects.

[0059] Similarly, it should be appreciated that in the description various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Moreover, the description of any individual drawing or aspect should not necessarily be considered to be an embodiment of the invention. Rather, as the following claims reflect, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

[0060] Furthermore, while some embodiments described herein include some features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form yet further embodiments, as will be understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0061] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practised without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0062] In the discussion of the invention, unless stated to the contrary, the disclosure of alternative values for the upper or lower limit of the permitted range of a parameter, coupled with an indication that one of said values is more highly preferred than the other, is to be construed as an implied statement that each intermediate value of said parameter, lying between the more preferred and the less preferred of said alternatives, is itself preferred to said less preferred value and also to each value lying between said less preferred value and said intermediate value.

[0063] The use of the term “at least one” may mean only one in certain circumstances. The use of the term “any” may mean “all” and / or “each” in certain circumstances.

[0064] The principles of the invention will now be described by a detailed description of at least one drawing relating to exemplary features. It is clear that other arrangements can be configured according to the knowledge of persons skilled in the art without departing from the underlying concept or technical teaching, the invention being limited only by the terms of the appended claims.

[0065] is a partially cutaway perspective view of a system for stabilising a cliff face. The cliff face comprises an exterior surface 10, which has a relatively steep gradient and for instance may lie adjacent to a railway. A barrier 20 is arranged adjacent to the exterior surface 10, and covers a substantial portion of the cliff face. The right-hand portion of the cliff face is not shown, in order to show the system within the underlying geology.

[0066] Directional drilling apparatus 30 is situated at a remote location 40, and has been used to drill a plurality of underground bores 50 through the underlying geology lying between the remote location 40 and the exterior surface 10 of the cliff face. The bores 50 are only shown in part, so as not to obscure the other features of the system. Each of the bores 50 is lined with a pipe 60, which extends from the remote location 40 to a point adjacent to the exterior surface 10 of the cliff face. Each pipe 60 stops short of the exterior surface 10, in other words, the point at which each pipe 60 terminates within each bore 50 is spaced from the exterior surface 10 by a distance D. The distance D may be the same for each of the plurality of pipes 60. Alternatively, the distance D may vary for each pipe 60, or for combinations of pipes 60.

[0067] A line 70 is arranged within each pipe 60, each line 70 extending between the remote location 40 and the barrier 20. Attachment means 80 attach an end of each line 70 to the barrier 20. A plurality of attachment means 80 are shown in a two-dimensional array which spans the cliff face, at substantially relatively intervals across the barrier 20.

[0068] The remote location 40 is anchored into the underlying geology by anchoring means 90, which are shown as solid foundations penetrating vertically down into the underlying geology. The directional drilling apparatus 30 may also be used to apply tension to the lines 70 after they are attached to the barrier 20 via attachment means 80. The tensioned lines 70 pull the barrier 20 back against the exterior surface 10, thereby transferring load to the remote location 70 and stabilising the cliff face.

[0069] is a partially cutaway perspective view of a system for stabilising two embankments. The exterior surfaces 10 of each embankment substantially face towards each other, and lie either side of a valley or cutting (for example for a railway or tunnel entrance). A barrier 20 is arranged adjacent to the exterior surface 10 of each embankment, and covers a substantial portion of each exterior face 10. Only the exterior surface 10 and barrier 20 of the left-hand embankment are shown, as the respective features of the right-hand embankment are obscured by the landmass.

[0070] Two directional drilling apparatuses 30 are positioned either side of the valley, at remote locations 110, 120 spaced from the exterior faces 10 of the embankments. The directional drilling apparatuses 30 have been used to drill a plurality of bores 50 through the underlying geology lying between each remote location 110, 120 and the respective exterior surface 10 of each embankment. Since each embankment is substantially longer than it is tall, the bores 50 are drilled in two wide two-dimensional arrays, although many other arrangements, such as an irregular pattern and / or three-dimensional array, are contemplated.

[0071] Only the openings of the bores 50 to the right of the figure are shown, so as not to obscure the other features of the system. Each of the bores 50 is lined with a pipe 60, which extends from each remote location 110, 120 to a point adjacent to the exterior surface 10 of each respective embankment. Each pipe 60 stops short of the exterior surface 10, in other words, the point at which each pipe 60 terminates within each bore 50 is spaced from each exterior surface 10 by a distance D. The distance D may be the same for each of the plurality of pipes 60. Alternatively, the distance D may vary for each pipe 60, or for combinations of pipes 60.

[0072] A line 70 is arranged within each pipe 60, each line 70 extending between each remote location 110, 120 and each respective barrier 20. Attachment means 80 attach an end of each line 70 to each respective barrier 20. A plurality of attachment means 80 are shown in a two-dimensional array which spans the exterior surface 10 of each embankment, at substantially relatively intervals across each barrier 20.

[0073] is a perspective cross-sectional view of a system for stabilising an embankment under a road 130. A portion of the embankment has fallen away in a landslide, exposing a surface 140 underneath. Directional drilling apparatus 30 is situated at a remote location 150. The directional drilling apparatus 30 has been used to drill a plurality of bores 50 through the underlying geology between the remote location 150 and the surface 140. A line is arranged inside each of the plurality of bores 50, extending between the remote location 150 and a barrier covering a substantial portion of the surface 140, attaching to the barrier via attachment means 80. The lines and the barrier are omitted from the drawing for the sake of clarity. The remote location 150 is anchored into the underlying geology by anchoring means 90.

[0074] is a detailed view of ground treatment being carried out through a pair of pipes 60 at a point along its length where it passes through unstable geology. A portion of the unstable surrounding geology and the pipe wall of one of the pipes 60 has been removed so as not to obscure the features of the system, though it is to be appreciated that his is for clarity in the drawings only. A plurality of probes 62 are inserted into unstable surrounding geology to facilitate the deployment of material 160 into the unstable surrounding geology. For example, the material may be a cementitious material configured to reinforce the surrounding geology.

Claims

A method of stabilising a landform, the method comprising the steps of:arranging a barrier adjacent to an exterior surface of a landform;drilling an underground bore between a remote location and the exterior surface;passing a line through the bore;attaching a first end of the line to the barrier; andtensioning the line by pulling the line through the bore.The method of stabilising a landform according to claim 1, the method further comprising the step of lining a first length of the bore with a pipe.The method of stabilising a landform according to claim 2, the method further comprising the step of anchoring the pipe into the underlying geology.The method of stabilising a landform according to claim 3, wherein the step of anchoring the pipe into the underlying geology comprises deployment of material and / or equipment into the underlying geology.The method of stabilising a landform according to any of claims 2 to 4, wherein the step of lining a first length of the bore with a pipe comprises driving the pipe into the bore.The method of stabilising a landform according to any of claims 2 to 5, wherein a second length of the bore adjacent to the barrier is not lined with a pipe.The method of stabilising a landform according to any of claims 2 to 6, further comprising the step of deploying material into the pipe.The method of stabilising a landform according to any preceding claim, the method further comprising the step of attaching a second end of the line adjacent to the remote location.The method of stabilising a landform according to any preceding claim, further comprising the step of monitoring tension and / or movement of the line.The method of stabilising a landform according to any preceding claim, further comprising the step of stabilising the underlying geology.A system for carrying out the method of stabilising a landform according to any preceding claim, the system comprising:a barrier for arranging adjacent to an exterior surface of a landform;directional drilling apparatus for drilling an underground bore through underlying geology;a line for passing through the bore;attachment means for attaching a first end of the line to the barrier; andtensioning means for pulling the line through the bore.

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