A mass wasting monitoring stake, system and method

Abstract

It is known to monitor earthworks and embankments such that damage caused by any mass wasting can be mitigated against. Stakes are known to be used; however, stakes that are driven too far into the ground may not be affected by movement of loose topsoil. In contrast, stakes that are not driven far enough into the ground are easily disrupted. In any event, even correctly deployed stakes can sag under their own weight, for example when a relatively heavy tilt sensor is attached off centre. The present invention provides a mass wasting monitoring stake, comprising first and second monitoring parts (1) and a primary connector (5) configured to releasably attach the first and second monitoring parts (1) together. In this way, the stake can be driven into the ground (11), deploying the first and second monitoring parts (1), and the primary connector (5) can subsequently release the first and second monitoring parts (1), such that relative movement between the first and second monitoring parts (1) can be detected if mass wasting were to occur.

Description

A MASS WASTING MONITORING STAKE, SYSTEM AND METHOD

[0001] The present invention relates generally to a mass wasting monitoring stake, system and method, and finds particular, although not exclusive, utility in monitoring mass wasting in earthworks and embankments.

[0002] Mass wasting is the mass movement of rock, soil, etc. under the force of gravity, typically down slopes, and can include some types of erosion. In particular, mass wasting may be via subsidence or via slope movement, for example including creep, solifluction, rockfall, debris flow, and landslides. Mass wasting may take place over timescales from seconds to hundreds of years.

[0003] It is known to monitor earthworks and embankments such that damage caused by any mass wasting can be mitigated against. A particular concern is landslips from embankments encroaching on property, roads or railways; or the collapse earthworks / embankments providing support to an asset such as road or rail or property.

[0004] One conventional method of monitoring such earthworks and embankments is to plant stakes in the ground, and then monitor the above-surface portions of these stakes (for instance with tilt sensors and / or automated total stations). However, stakes that are driven too far into the ground may not be affected by movement of loose topsoil. In contrast, stakes that are not driven far enough into the ground are easily disrupted by human or animal activity, vegetation and / or weather, leading to false alarms. In any event, even correctly deployed stakes can sag under their own weight, for example when a relatively heavy tilt sensor is attached off centre.

[0005] Another conventional method of monitoring such earthworks and embankments is to embed sensors in grout within boreholes below ground. However, these are time consuming and expensive to install, and can often be ineffective at detecting small movements.

[0006] According to a first aspect of the present invention, there is provided a mass wasting monitoring stake, comprising: a first monitoring part; a second monitoring part; and a primary connector configured to releasably attach the first monitoring part to the second monitoring part.

[0007] In this way, the stake may be driven into the ground using a lump hammer, sledgehammer, pile driver or similar tool. The primary connector can releasably attach the first monitoring part to the second monitoring part such that the relative positions of the first and second monitoring parts are maintained during deployment of the stake, the stake can be driven into the ground, thereby deploying the first and second monitoring parts, and the primary connector can subsequently release the first and second monitoring parts, such that the relative positions of the first and second monitoring parts are no longer maintained after deployment of the stake, and relative movement between the first and second monitoring parts can be detected if mass wasting were to occur. As such, the stake can allow for mass wasting measurements, and mass wasting monitoring, across two or more layers of the ground.

[0008] The first and second monitoring parts may be configured to be deployed, for example, into the ground.

[0009] Deployment of the first and second monitoring parts may comprise driving the stake into the ground, such that the first and second monitoring parts are driven into the ground. For example, by using a lump hammer, sledgehammer, pile driver or similar tool.

[0010] The primary connector may releasably attach the first monitoring part to the second monitoring part such that the relative positions of the first and second monitoring parts are maintained during deployment of the stake. For example, the relative position of the first and second monitoring parts may be maintained by preventing lateral and / or longitudinal displacement of the first and second monitoring parts relative to each other.

[0011] In this way, the first monitoring part and the second monitoring part can be held together, such that the impulse directed to the stake while being driven into the ground during deployment would not result in relative movement between the first and second monitoring parts.

[0012] The primary connector may release the first monitoring part from the second monitoring part after deployment of the stake, such that the relative positions of the first and second monitoring parts are no longer maintained.

[0013] In this way, the first and second monitoring part can be displaced from each other after deployment of the stake, such that there would be relative movement between the first and second monitoring parts that can be detected, if mass wasting were to occur.

[0014] The first and second monitoring parts may be configured to monitor mass wasting across and / or through two or more layers of the ground. For example, the first monitoring part may be deployed into the topmost layers of the ground, and the second monitoring part may be deployed into deeper layers of the ground.

[0015] In this way, the first and second monitoring parts can be affected by movement of two or more layers of the ground, thereby allowing the relative movement between the first and second monitoring parts to be detected and / or measured to monitor mass wasting across two or more layers of the ground.

[0016] The stake may comprise an elongate body (for instance incorporating the first and second mounting parts) terminating in a pointed end of being driven into ground.

[0017] The stake may comprise a third (or more) monitoring part, such that the stake comprises a plurality of monitoring parts.

[0018] The primary connector may be releasably attachable to both the first and the second monitoring part. For example, the primary connector may clamp the first and second monitoring parts together.

[0019] Each of the monitoring parts may comprise a hole therethrough. The primary connector may comprise a line, and the line may be configured to extend through the holes in one or more (or the or each) of the monitoring parts, for example so that all monitoring part(s) are threaded onto the line.

[0020] The stake may further comprise a spike, for example adjacent to a first end of the line. The spike may be attached to the line.

[0021] Alternatively, the spike may be attached to one of the monitoring parts (in use, a lowermost monitoring part). In such cases, the line may not extend through the hole in the lowermost monitoring part, but instead be attached to the lowermost monitoring part, for example by means of co-operating screw threads, cam, or other mechanism.

[0022] The stake may further comprise a cap, for example adjacent to a second end of the line opposing the first end. The cap may be attached to the line.

[0023] The monitoring parts may be clamped together between the cap and the spike.

[0024] The spike may be removably attached to the line, for example by means of co-operating screw threads, cam, or other mechanism. Similarly, the cap may be removably attached to the line, for example by means of co-operating screw threads, cam, or other mechanism.

[0025] The cap may comprise a nut (e.g. a wing nut) and optionally a washer, such that the wing nut may be tightened to clamp the monitoring parts together between the cap and the spike.

[0026] The cap may be embodied as part of one of the monitoring parts (in use, an uppermost monitoring part). In such cases, the line may be attached to the uppermost monitoring part, for example by means of co-operating screw threads, cam, or other mechanism.

[0027] The line may comprise a rod; that is, a substantially rigid member.

[0028] Once in the ground, the cap may be removed and / or released (e.g. the top nut may be unscrewed), and then the rod is twisted to unscrew it from the bottom spike, releasing it and allowing it to be fully withdrawn. The spike and / or monitoring parts may include fins, wings, cut-outs, ridges or other features that resist the turning force required to unscrew or disengage the rod once in the ground.

[0029] The sections left in the ground are then able to move independently, and if the layer of earth they are embedded in moves, they will move with it.

[0030] Alternatively, the line may be flexible. For example, the line may be a cord, string, wire or other flexible component. In particular, the line may be a high tensile cord (e.g. steel wire); in this way, damage to the line can be prevented.

[0031] The line may be attached (e.g. permanently fixed or fixedly attached) to the spike and / or the lowermost monitoring part. The line may be releasably attached to the cap and / or the uppermost monitoring part. In particular, during installation, the line may be held under tension between the spike and the cap, thereby holding the monitoring parts together under compression.

[0032] Once in the ground, the cap may be removed and / or released, releasing the flexible line. The sections left in the ground are then able to move independently, and if the layer of earth they are embedded in moves, they will move with it.

[0033] The line may be provided with an extension portion (e.g. a portion that is not held under tension prior to deployment). For example, the line may be attached to the spike and / or the lowermost monitoring part at a first location along the line (which may be a first end of the line or spaced from the first end of the line), and the line may be releasably attached to the cap and / or the uppermost monitoring part at a second location on the line, spaced from the first location and spaced from a second end of the line opposing the first end. The extension portion may extend from the second location on the line to the second end of the line. The second end of the line may be may be attached (e.g. permanently fixed or fixedly attached) to the cap and / or the uppermost monitoring part. In this way, once deployed, the line may be free to slide through the holes within the monitoring parts to allow them to separate by a first amount, but will prevent relative movement by a larger amount. Accordingly, recovery of the monitoring parts will be enabled.

[0034] As a further alternative, the primary connector may be releasably attachable to the first and / or the second monitoring part. For example, the primary connector may be permanently attached to the first monitoring part and releasably attachable to the second monitoring part.

[0035] For example, the primary connector may comprise permanent and / or electromagnets, frangible members, interlocking components (e.g. including a friction fit), sliding bolts, hook-and-loop fasteners, and / or any other suitable coupling. In some arrangements the primary connector may comprise a ball joint between the first and second monitoring parts.

[0036] The primary connector may be remotely operated, so that the coupling may be releasable upon actuation.

[0037] As a further alternative the primary connector may comprise a first primary connection portion permanently attached to the first monitoring part, and a second primary connection portion permanently attached to the second monitoring part, and the first and second primary connection portions may be releasably attachable to each other.

[0038] Releasable attachment in the context of any part of this application may comprise frangible attachment, or re-securable attachment.

[0039] In addition to the primary connector, the stake may comprise a secondary connector between the first and second monitoring parts.

[0040] The secondary connector may also be configured to releasably attach the first monitoring part to the second monitoring part. However, in preferred embodiments, connection provided by the secondary connector may be more easily broken by mass wasting than connection provided by the primary connector. The secondary connector may be releasably attachable to the first and / or the second monitoring part. For example, the secondary connector may be permanently attached to the second monitoring part and releasably attachable to the second monitoring part. Alternatively, the secondary connector may be releasably attachable to both the first and the second monitoring part. As a further alternative the secondary connector may comprise a first secondary connection portion permanently attached to the first monitoring part, and a second secondary connection portion permanently attached to the second monitoring part, and the first and second secondary connection portions may be releasably attachable to each other.

[0041] For example, the secondary connector may comprise permanent and / or electromagnets, frangible members, interlocking components (e.g. including a friction fit), hook-and-loop fasteners, and / or any other suitable coupling. This would allow them to resist small amounts of movement, but still pull apart if there was significant movement.

[0042] In some arrangements the secondary connector may comprise a ball joint between the first and second monitoring parts.

[0043] The secondary connector may comprise a flexible connector, such as a line, cable or wire. In this way, the first and second monitoring parts may remain indirectly connected even after they have been moved relative to each other.

[0044] The secondary connector may be a resilient connector, for example comprising a spring, elastic, etc.

[0045] Each monitoring part may comprise a sensor, only one sensor, at least one sensor or a plurality of sensors for determining relative movement between the first and second monitoring parts.

[0046] The or each sensor may comprise a proximity sensor for determining the relative location of the respective monitoring part relative to another one of the monitoring parts (e.g. an adjacent monitoring part).

[0047] The proximity sensor may comprise, for example, a Hall effect sensor. In particular, the Hall effect sensor on one monitoring part may measure the strength of a magnetic field of a (e.g. permanent) magnet on an adjacent monitoring part. The proximity sensor may comprise a plurality of Hall effect sensors (e.g. three Hall effect sensors arranged to measure respective directional axes; i.e. a 3D Hall effect sensor).

[0048] The proximity sensor may comprise processing means for determining a distance and / or direction of the monitoring part. However, in alternative arrangements and processing may be carried out remotely, as described below.

[0049] The or each sensor may comprise a tilt sensor, inclinometer and / or gyroscope for determining a change in orientation of the respective monitoring part, and these may be operable to provide an orientation about three independent axes.

[0050] The or each sensor may comprise an accelerometer and / or Inertial Measurement Unit for determining movement and / or vibration of the respective monitoring part.

[0051] The or each sensor may comprise environmental sensors, for determining factors such as moisture or water level (e.g. through resistivity).

[0052] Each sensor may be provided with a respective power supply, and may be configured to communicate wirelessly with each other, or with a separate processor. However, in preferred embodiments, each sensor may be connected via a flexible connector, such as a line, cable or wire, to allow power supply and / or communication therealong. The length of the flexible connector may be sufficiently long enough so that the sections can move freely and completely away from each other. For example, the flexible connector may be coiled inside or between adjacent monitoring parts during installation.

[0053] The stake may further comprise a control unit that may be disposed in the uppermost monitoring part (in use), above the uppermost monitoring part (in use), for instance adjacent to (e.g. on) the ground surface, and / or in the cap. A single control unit may be connected to a plurality of stakes, or only one stake.

[0054] The control unit may comprise a power supply (e.g. battery or solar cell), a microprocessor (and / or associated memory components), a transmitter (and optionally a receiver), and / or any other suitable component such as a user interface. In this way, the control unit may process signals from the sensors to determine movement and report this to a remote station, and / or may forward the signals from the sensors to a remote station for further processing by the remote station to determine movement.

[0055] For example, a potential implementation may involve a magnet in the top of each monitoring part and in the spike, and a 3D Hall effect sensor in the bottom of each monitoring part (and optionally in the control unit). These would allow the orientation and distance of each section relative to another to be monitored. In addition, the top monitoring part and / or the cap may contain a 3D tilt sensor or accelerometer to accurately and independently determine its orientation in all three axes.

[0056] Alternatively, the monitoring parts may comprise only passive components; that is, no active sensing components. In this way, active sensor components could be placed down the holes in the monitoring parts once the rod has been removed, and the active sensor components could then monitor movement of the monitoring parts in a similar manner to that discussed above, for example by the inclusion of permanent magnets on the monitoring parts, and 3D Hall effect sensors as part of the active sensor components.

[0057] The stake may be substantially cylindrical in shape; that is, having a circular cross section along a majority of its length. Alternatively, the stake may be substantially blade like; that is having a length substantially greater than its width, and the width substantially greater than its depth (in this context, substantially greater meaning at least five times greater, in particular at least ten times greater). However, other shapes and / or cross sections are also envisaged.

[0058] The stake may be between 30cm and 4m in length, in particular between 50cm and 2m, more particularly between 70cm and 1.5m. However, in some arrangements the stake may be longer than 4m.

[0059] The stake could be made of any material robust enough to take the force of being driven into the ground and remain chemically stable for the duration of the monitoring project. The material may comprise metal, plastics material, glass-reinforced plastic (GRP) or other fibre reinforced plastic / resin. The material may be biodegradable (e.g. wood, PLA, etc), so that this would eventually leave just the sensors in the ground after significant periods of time had passed.

[0060] According to a second aspect of the present invention, there is provided a mass wasting monitoring system, comprising: the mass wasting monitoring stake of the first aspect; and a stake driver to sit over an upper end of the stake, in use, to distribute force of hammer blows over the stake.

[0061] According to a third aspect of the present invention, there is provided a method of monitoring mass wasting, the method comprising the steps of: providing the mass wasting monitoring stake of the first aspect; driving the stake into the ground; using the primary connector to release the first monitoring part from the second monitoring part.

[0062] In some implementations, the method may further comprise the step of forming a pilot hole in the ground, before driving the stake into the ground, e.g. in the pilot hole. For example, a hand-held auger (manual or power tool) may be used.

[0063] The first monitoring part may determine relative moment of the second monitoring part, relative to the first monitoring part.

[0064] 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.

[0065] is a perspective view of a first mass wasting monitoring stake.

[0066] is a partially exploded view of the first mass wasting monitoring stake of.

[0067] is a partial cutaway view of the first mass wasting monitoring stake ofdeployed below ground.

[0068] is a schematic representation of mass wasting of a portion of ground, with the mass wasting monitoring stake ofdeployed therein.

[0069] is a perspective view of a stake driver atop the first mass wasting monitoring stake of.

[0070] is a detailed view of an interface between the stake driver ofand the first mass wasting monitoring stake of.

[0071] is a perspective view of a second mass wasting monitoring stake in a first configuration.

[0072] is a perspective view of the second mass wasting monitoring stake ofin a second configuration.

[0073] is a detailed exploded view of the primary connector of the second mass wasting monitoring stake of.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] Similarly, it is to be noticed that the term “connected”, used in the description, should not be interpreted as being restricted to direct connections only. Thus, the scope of the expression “a device A connected to a device B” should not be limited to devices or systems wherein an output of device A is directly connected to an input of device B. It means that there exists a path between an output of A and an input of B which may be a path including other devices or means. “Connected” may mean that two or more elements are either in direct physical or electrical contact, or that two or more elements are not in direct contact with each other but yet still co-operate or interact with each other. For instance, wireless connectivity is contemplated.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] is a perspective view of a first mass wasting monitoring stake, comprising four monitoring parts 1 stacked atop each other, a spike 3 located below the lowermost monitoring part, a rod 5 extending through a central hole (not shown) of each of the four monitoring parts 1 and threadedly engaged with the spike 3, and a wingnut 7 threadedly mounted on the rod 5 to clamp the four monitoring parts 1 together against the spike 3.

[0087] is a partially exploded view of the first mass wasting monitoring stake of, in which the rod 5 can be seen extending between the monitoring parts 1 and into the spike 3. In addition, on an upper surface of each of the monitoring parts is a magnet 9, located such that a Hall effect sensor (not shown) in each adjacent monitoring part 1 may be able to determine movement of the monitoring part 1 relative to the adjacent monitoring part 1.

[0088] is a partial cutaway view of the first mass wasting monitoring stake ofdeployed below a ground surface 11, and after the rod (not shown) has been removed. Located above the uppermost one of the monitoring parts 1, and on the ground surface 11, is a control unit 13 for receiving and processing signals from the Hall effect sensors (not shown). The control unit 13 is provided with an antenna 15 for communicating any mass wasting to a remove station.

[0089] is a schematic representation of mass wasting of a portion of ground, with the mass wasting monitoring stake ofdeployed therein, and with the rod (not shown) removed. The ground in which the four monitoring parts 1 are placed has been divided into twenty-three distinct layers 17. The layers 19 in which the lowermost two monitoring parts 1a, 1b are located have not moved.

[0090] However, the layers 21 in which the second-highest monitoring part 1c is located has slipped by a first distance to the right of the figure. Movement of the associated monitoring part 1c can also be seen to have moved a similar distance. The relative movement of the associated monitoring part 1c relative to the second-lowest monitoring part 1b can be detected by the Hall effect sensors (not shown).

[0091] Similarly, the layers 23 in which the uppermost monitoring part 1d is located has slipped by a second distance, double the first distance, to the right of the figure. Movement of the associated monitoring part 1d can also be seen to have moved a similar distance. The relative movement of the uppermost monitoring part 1d relative to the second-highest monitoring part 1c can also be detected by the Hall effect sensors (not shown).

[0092] is a perspective view of a stake driver 25 atop the first mass wasting monitoring stake of. The stake driver is provided with a large flat top for receiving hammer blows thereon. This enables the impulse from even inexpertly-directed hammer blows to be directed towards appropriate parts of the mass wasting monitoring stake, for example so as to avoid contact with the wingnut (not shown) which might otherwise prevent removal of the wingnut, and thereby the rod (not shown), due to damage thereto.

[0093] is a detailed view of an interface between the stake driver 25 ofand the first mass wasting monitoring stake of. The stake driver 25 includes a cutout portion 27 corresponding to the shape of the wingnut 7, and an internal bore 29 shaped to receive the rod 5, such that hammer blows made onto the flat top of the stake driver 25 will be directed to the uppermost monitoring part 1, avoiding the wingnut 7 and the rod 5.

[0094] is a perspective view of a second mass wasting monitoring stake in a first configuration, in which a first monitoring part 31 sits above a second monitoring part 33. In contrast to the first mass wasting monitoring stake of the preceding figures, no rod is necessary. In addition, no spike or sensors are shown for clarity only; these could be incorporated in some embodiments.

[0095] Connection between the first monitoring part 31 and the second monitoring part 33 is via mutually engaging parts as follows. A first arm 35 extends downward from the first monitoring part 31 toward a laterally extending first hook 37. Similarly, a second arm 39 extends upward from the second monitoring part 33 toward a laterally extending second hook 41. The respective arms 35, 39 and hooks 37, 41 are of similar size and shape, and are configured for mutual engagement.

[0096] Secure connection such as this can ensure that the mass wasting monitoring stake can be effectively driven into the ground, without lateral or longitudinal displacement of the two parts, relative to each other.

[0097] is a perspective view of the second mass wasting monitoring stake ofin a second configuration in which the first monitoring part 31 has been rotated 90 degrees about a vertical axis, such that the respective hooks 37, 41 no longer engage with each other.

[0098] This rotation can be performed to disengage the first 31 and second 33 monitoring parts after deployment into the ground.

[0099] is a detailed exploded view of the primary connector of the second mass wasting monitoring stake of, shown where the first monitoring part (not shown) has been moved substantially axially away from the second monitoring part 33, as might occur during mass wasting.

Claims

A mass wasting monitoring stake, comprising:a first monitoring part;a second monitoring part; anda primary connector configured to releasably attach the first monitoring part to the second monitoring part.The mass wasting monitoring stake of claim 1, comprising a third monitoring part.The mass wasting monitoring stake of claim 1 or claim 2, wherein the primary connector is configured to clamp the first and second monitoring parts together.The mass wasting monitoring stake of any preceding claim, wherein each of the monitoring parts comprises a respective hole therethrough, and the primary connector comprises a rod configured to extend through the holes in the monitoring parts.The mass wasting monitoring stake of claim 4, further comprising a spike removably attached to the rod at a first end of the rod.The mass wasting monitoring stake of claim 5, further comprising a cap removably attached to the rod at a second end of the rod opposite the first end.The mass wasting monitoring stake of claim 6, wherein the monitoring parts are clamped together between the cap and the spike.The mass wasting monitoring stake of any preceding claim, wherein each monitoring part comprises a sensor for determining relative movement between the first and second monitoring parts.The mass wasting monitoring stake of any preceding claim, further comprising a control unit disposed adjacent to the ground surface.A mass wasting monitoring system, comprising:the mass wasting monitoring stake of any preceding claim; anda stake driver to sit over an upper end of the stake, in use, to distribute force of hammer blows over the stake.A method of monitoring mass wasting, the method comprising the steps of:providing the mass wasting monitoring stake of any one of claims 1 to 9;driving the stake into the ground;using the primary connector to release the first monitoring part from the second monitoring part.

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