PORE PRESSURE MONITORING DEVICE AND METHOD FOR MONITORING PORE WATER PRESSURE

Abstract

The invention relates to a pore pressure monitoring device, for use in geotechnical engineering, adapted to be deployed underground for monitoring pore-water pressure in the ground, comprising a pressure sensor cavity (2) and a pressure sensor means (4), for sensing a fluid (6) pressure of a fluid in the sensor cavity (2), further comprising a degassing means (10), comprising a gas discharge means (14) and a gas-water filter means (12), wherein the gas-water filter means (12) is adapted for providing a route for gas (8) to escape from the fluid (6) in the sensor cavity (2), towards the gas discharge means (14) for discharging the filtered gas (8) to the atmosphere. The invention also relates to a method for monitoring pore-water pressure.

Claims

1. A pore pressure monitoring device for monitoring pore-water pressure in a surrounding ground, comprising: a pressure sensor cavity; a housing surrounding the pressure sensor cavity; a pressure sensor configured to sense a fluid pressure of a fluid in the pressure sensor cavity, wherein the pressure sensor cavity is in fluid communication with the surrounding ground to enable equalisation of outside and inside pressure of the pressure sensor cavity; and a gas discharge tube and a gas-water filter, wherein the gas-water filter is configured to provide a route for gas to escape from the fluid in the pressure sensor cavity towards the gas discharge tube for discharging filtered gas to an atmosphere.

2. The pore pressure monitoring device according to claim 1, wherein the gas discharge tube extends from the pressure sensor cavity to or above ground establishing a gas connection to the atmosphere.

3. The pore pressure monitoring device according to claim 1, wherein the gas discharge tube comprises an inner lumen extending from the pressure sensor cavity to above ground.

4. The pore pressure monitoring device according to claim 1, wherein the gas discharge tube comprises a discharge tube having an inner lumen.

5. The pore pressure monitoring device according to claim 1, wherein the gas-water filter is guided at least partially within the gas discharge tube.

6. The pore pressure monitoring device according to claim 1, wherein the gas-water filter comprises a gas permeable membrane for separation of the gas from the fluid in the pressure sensor cavity.

7. The pore pressure monitoring device according to claim 6, wherein the gas permeable membrane is made from a hydrophobic material.

8. The pore pressure monitoring device according to claim 6, wherein the gas permeable membrane is provided as a gas permeable membrane fibre or tube.

9. The pore pressure monitoring device according to claim 1, wherein a projecting portion of the gas-water filter projects inside the pressure sensor cavity.

10. The pore pressure monitoring device according to claim 1, wherein the gas-water filter comprises a closed distal end portion, which is impermeable at least for water.

11. The pore pressure monitoring device according to claim 1, wherein the gas-water filter is coupled to and/or at least partially guided within the gas discharge tube.

12. The pore pressure monitoring device according to claim 1, wherein the gas-water filter is provided at least partially as the gas discharge tube.

13. The pore pressure monitoring device according to claim 1, wherein the gas-water filter substantially extends from the pressure sensor cavity to essentially above ground.

14. The pore pressure monitoring device according to claim 1, wherein the gas discharge tube comprises an outer protection sleeve.

15. The pore pressure monitoring device according to claim 1, wherein the gas discharge tube and/or the gas-water filter are made of a flexible material.

16. The pore pressure monitoring device according to claim 1, wherein the housing surrounding the pressure sensor cavity comprises a fluid filter comprising a slotted or screened portion and configured to filter fluid out of a ground.

17. The pore pressure monitoring device according to claim 1, further comprising: a data connection for communicational coupling the pressure sensor with a data receiver positioned substantially outside a ground, wherein the gas discharge tube and the data connection are at least over a section guided within a protection tube.

18. The pore pressure monitoring device according to claim 1, wherein the gas discharge tube is at least over a section guided within the housing and at least partially surrounding the pressure sensor cavity.

19. The pore pressure monitoring device according to claim 1, wherein the housing comprises a bore and the gas discharge tube is at least over a section guided of the housing.

20. A method for monitoring pore water pressure by use of a pore pressure monitoring device, the method comprising: deploying the pore pressure monitoring device underground; monitoring pore-pressure data received by a pressure sensor of the pore pressure monitoring device; discharging gas accumulated in a pressure sensor cavity of the pore pressure monitoring device via a gas discharge tube to an atmosphere.

Description

[0036] These and other features, aspects, and advantages of the devices and methods of the present disclosure will become better understood from the following description, appended claims, and accompanying drawings, wherein:

[0037] FIG. 1a shows a schematic cross-section of one embodiment of the pore pressure monitoring device according to the invention;

[0038] FIG. 1b shows a more detailed schematic excerpt of FIG. 1a;

[0039] FIG. 2 shows a schematic isometric view of the embodiment used in FIG. 1a;

[0040] FIG. 3 shows a schematic isometric view of a part of another embodiment of FIG. 2;

[0041] FIG. 4 shows schematically embodiments of degassing means; and

[0042] FIG. 5 shows schematically the degassing means at least partially inserted into a housing and similar parts of an embodiment of the pore pressure monitoring device according to the invention.

[0043] With regard to the accompanying drawings, for identical or similar parts identical reference signs are used, wherein indices might be set.

[0044] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs as read in the context of the description and drawings. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. In some instances, detailed descriptions of well-known devices and methods may be omitted so as not to obscure the description of the present systems and methods. Terminology used for describing particular embodiments is not intended to be limiting of the invention. As used herein, the singular forms a, an and the are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term and/or includes any and all combinations of one or more of the associated listed items. It will be understood that the terms comprises and/or comprising specify the presence of stated features but do not preclude the presence or addition of one or more other features. It will be further understood that when a particular step of a method is referred to as subsequent to another step, it can directly follow said other step or one or more intermediate steps may be carried out before carrying out the particular step, unless specified otherwise. Likewise it will be understood that when a connection between structures or components is described, this connection may be established directly or through intermediate structures or components unless specified otherwise. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control.

[0045] The invention is described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The description of the exemplary embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. In the drawings, the absolute and relative sizes of systems, components, layers, and regions may be exaggerated for clarity. Embodiments may be described with reference to schematic and/or cross-section illustrations of possibly idealized embodiments and intermediate structures of the invention. Relative terms as well as derivatives thereof should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description and do not require that the system be constructed or operated in a particular orientation unless stated otherwise.

[0046] FIGS. 1a and 1b disclose one embodiment of a pore pressure monitoring device 1, and especially a tensiometer or a piezometer, for use in geotechnical engineering and especially for being deployed underground for monitoring pore-water pressure in the surrounding ground 40 according to the invention. FIG. 1b shows a more detailed schematic excerpt of the pore pressure monitoring device 1 according to FIG. 1a.

[0047] The pore pressure monitoring device comprises a pressure sensor cavity 2, in this embodiment surrounded by a housing 26. The housing 26 here comprises a cone tip 27. With regard to the housing, different embodiments are possible to be provided, for example multi-part housings, comprising multiple parts couplable with each other. Further multi-layer housings are possible comprising multiple layers for providing the sensor cavity or similar cavities needed for measurement or storage purposes.

[0048] Within the housing a pressure sensor means 4 is arranged, which is for example arranged for measuring fluid pressure of a fluid 6 in the cavity 2. Besides measurement of pressures, the pressure sensor means could also be provided as any other analysis means, for example for gas analysis, water analysis or a similar fluid analysis, when required. Thereby it is not necessary that means for measuring the pressure of the fluid are provided as well. For ease of understanding therefore in the whole application the pressure sensor means is a means for measuring not only pressure, but also or instead any other variables necessary in geotechnical engineering.

[0049] The pore pressure monitoring device 1 is alternatively further provided with a data connection means 30 for communicational coupling of the pressure sensor means 4 with a data receiving means 32 substantially on or outside the ground 40. This data receiving means can be any kind of means for receiving the data collected by the sensor means 4 in the cavity 2 or any other sensor means arranged at the pore pressure monitoring device deployed in the ground 40. The data connection means 30 can for example be a cable for electric data transmission. Any other embodiments of data connection means are usable. The data connection means 30 may be guided within a protection means 34, here for example provided as a tube extending from the housing 26 of the pore pressure monitoring device to substantially above ground 40/to atmosphere 42. In principle the cavity is in fluid communication with the surrounding ground 40, so as to allow equalisation of outside and inside pressure and ensure that no granular/solid pressure is exerted to the pressure sensor means (4). For that, the housing 26 surrounding the sensor cavity may be provided at least partially fluid permeable, and especially comprising a fluid-solid filter means 13, so as to allow equalisation of outside and inside pressure, i.e. the pressure outside and inside the cavity, and at the same time ensure that no granular/solid pressure is exerted to the pressure sensor means 4.

[0050] Especially in this regard, the housing 26 is alternatively provided with a fluid filter means 28 and especially a particle filter, optionally with a slotted and/or screened and/or porous portion, for filtering fluid 6 out of the ground 40. Dependent on the fluid 6 which has to be filtered different fluid filter means 28 are usable.

[0051] For discharging of gas accumulating in the cavity over time a degassing means 10 is provided arranged within the pore pressure monitoring device 1.

[0052] The degassing means comprises a gas discharge means 14 for discharging gas 8 separated from the fluid 6 in the sensor cavity 2 to above ground 40 and/or to the atmosphere 42. The discharged gas 8 can be discharged to the atmosphere 42, which is also meant to be any position or means close to above ground 40, at the ground surface or above ground 40 or to any other further storage or analysis means. For that reason alternatively an atmosphere connection means 24 is provided for further processing of the filtered gas, i.e. for discharging it to the atmosphere 42 or for guiding it to further processing means, like storage tanks, analysis means, etc. Optionally, the gas discharge means extends from the sensor cavity to or above the ground surface and further optionally allows for other purposes such as sampling and in-situ calibration.

[0053] As shown with FIGS. 1a and 1b, the sensor means 4 can be arranged within the cavity 2.

[0054] Alternatively, the gas discharge means 10 extends from the sensor cavity 2 to above ground 40 and/or the atmosphere connection means 24, and especially in such a way that it is establishing fluid connection to above ground 40, allowing for discharge of the gas.

[0055] As shown with FIGS. 4 and 5, alternatively the gas discharge means comprises an inner lumen 16 especially extending from the sensor cavity 2 above ground 40. The discharge means 14 can for example be provided as a discharge tube or a similar means having an inner lumen 16.

[0056] The degassing means further comprises a gas-water filter means 12 for separating gas 8 out of the fluid 6. It is possible to guide the gas-water filter means 12 at least partially within the gas discharge means 14 and especially within an inner lumen of the gas discharge means, especially when the gas discharge means 14 is provided as a tube. It is, for example, possible to arrange the gas-water filter means 12 in such a way that it can be entered and distracted from the gas discharge means 14 even when the pore pressure monitoring device is already deployed in the ground.

[0057] With regard to the gas discharge means, it is possible to couple the gas-water filter means 12 to that gas discharge means 14 or to guide the gas-water filter means within the gas discharge means in total, especially from the cavity 2 to above ground 40 or to the atmosphere connection means 24 etc. Connecting the gas-water filter means 12 to the gas discharge means can be done via a coupling element arranged at the proximal and distal portions of the two means respectively or via guiding the gas-water filter means at least partially within the discharge means 14 and fixing the respective means together after a respective portion. Of course, also guiding of the gas-water filter means 12 at least partially outside and especially over the gas discharge means 14 is possible. Here also the above mentioned coupling of the gas-water filter means 12 to the gas discharge means 14 is possible.

[0058] In general, it is also possible that the gas-water filter means 12 is provided at least partially as the gas discharge means 14 and arranged for discharging the gas 8 from the cavity 2 to above ground 40 etc. or to a gas discharge means arranged distant from the cavity 2. If the gas-water filter means is, for example, a permeable membrane tube, it is possible to use that membrane tube for discharging the gas from the cavity to above ground 40 or to a gas discharge means arranged distant from the cavity 2. As schematically shown with FIG. 1a, the gas-water filter means 12 comprises a gas permeable membrane 18 for separating or filtering the gas 8 from the fluid 6 in the sensor cavity. This filtered gas 6 can then be discharged via the discharge means 14 to above ground 40. The gas-water filter means is especially adapted for providing a route for gas 8 to escape from the fluid 6 in the sensor cavity 2 towards the gas discharge means 14 for discharging the filtered gas 8 to above ground and especially to the atmosphere 42.

[0059] As in detail shown with FIGS. 2 and 3, the housing 26 at least partially provides the cavity 2. Within that cavity 2 the sensor means 4 is arranged.

[0060] By reliably coupling the degassing means 10 to the cavity 2, so that the fluid 6 within the cavity can make contact with the degassing means, dissolved gasses can migrate towards and trough the degassing means. The water remains in the cavity occupying all space, while the separated gas escapes therefrom; the degassing means 10 is alternatively guided within a bore 36 in the housing 26 or at least a part 37 of the housing. It is possible to fix the degassing means 10 within that bore 36, for example via friction bonding, gluing etc. and especially gas and/or fluid tight gluing or similar fixation.

[0061] As shown with this embodiment, the gas-water filter means 12 can be arranged at the most upper portion of the cavity 2, so that gases accumulating in the cavity 2 are directed to the degassing means.

[0062] FIGS. 4 and 5 disclose embodiments of the degassing means 10 comprising the discharge means 14 and the gas-water filter means 12.

[0063] As already mentioned before, the gas discharge means 14 can comprise a discharge tube having an inner lumen 16. Within that inner lumen 16 the gas-water filter means 12 can be at least partially guided and can for example extend from the cavity 2 to a position above ground 40. For filtering the gas out of the fluid 6, which preferably is water, the gas-water filter means 12 can be provided or can comprise a gas permeable membrane 18 especially made from a hydrophobic material. The gas permeable membrane 18 can be provided as a gas permeable membrane fibre 19 as, for example, shown with FIGS. 4 and 5. For securing reliable gas separation, it is possible to provide the gas-water filter means and especially such a filter means 12 provided as a gas permeable membrane fibre 19 with a closed distal end portion 22, which is impermeable at least for water.

[0064] As shown with FIGS. 3 and 5, the gas-water filter means 12 can comprise a projecting portion 20 which projects inside the cavity 2. It is possible to arrange the gas-water filter means 12 in such a way that it projects from the gas discharge means 14 as well, which is for example shown with FIGS. 4 and 5. As mentioned, it is also possible to provide the gas-water filter means as the gas discharge means 14. With such an embodiment, the gas-water filter means is arranged in such a way that it can also discharge the gas in direction to above ground and within a special embodiment from the cavity 2 to above ground 40. Here also additional protection tubes and sleeves, respectively, can be used for protecting the gas-water filter means 12. In general, it is possible to provide the discharge means and/or the gas-water filter means made of a flexible material and especially plastic material. Especially for the gas-water filter means it is possible to provide it made from a hydrophobic material. This, of course, also applies for the material of the gas discharge means 14.

[0065] As for example shown with FIG. 1a, the degassing means 10 and the data connection means 30 can at least over a section be guided within a joint protection means 34 and especially a protection tube. It is also possible to provide distinct protection tubes for each of the means 10, 30. Further, it is possible to provide the pore pressure monitoring device with respective coupling devices 38 for coupling such means 30 extending to above ground 40 to the housing 26 or a similar parts of the pore pressure monitoring device 1 deployed in the ground. Multiple and/or individual coupling means can for example be provided with individual parts of the degassing means 10, e.g. the discharge means 14, the gas-water filter means 12 and/or the data connection means 30. Here, individual coupling means as well as grouped coupling means for connecting multiple of these parts simultaneously are usable.

[0066] The invention also relates to a method for monitoring pore-water pressure by use of the pore pressure monitoring device as explained before. This method comprises the steps of deploying the pore pressure monitoring device 1 underground; monitoring pore-pressure data received by the pressure sensor means 4, discharging gas 8 accumulated in the sensor cavity 2 of the pore pressure monitoring device 1 via the degassing means 10 above ground 40 and especially to the atmosphere. For deploying the pore pressure monitoring device 1 into ground, it is inter alia possible to either introduce the device 1 into a bore hole 52 and seal the bore hole via clay, bentonite, concrete or a similar sealing means 54 (this is shown, for example, with FIG. 1a) or to push the device 1 into ground to the installation and intended measurement position.

[0067] For the purpose of clarity and a concise description, features are described herein as part of the same or separate embodiments, however, it will be appreciated that the scope of the invention may include embodiments having combinations of all or some of the features described.

[0068] While the present systems and methods have been described in particular detail with reference to specific exemplary embodiments thereof, it should also be appreciated that numerous modifications and alternative embodiments may be devised by those having ordinary skill in the art without departing from the scope of the present disclosure. For example, embodiments wherein devices or systems are disclosed to be arranged and/or constructed for performing a specified method or function inherently disclose the method or function as such and/or in combination with other disclosed embodiments of methods or systems. Furthermore, embodiments of methods are considered to inherently disclose their implementation in respective hardware, where possible, in combination with other disclosed embodiments of methods or systems. Furthermore, methods that can be embodied as program instructions, e.g. on a non-transient computer-readable storage medium, are considered inherently disclosed as such embodiment.

[0069] Finally, the above-discussion is intended to be merely illustrative of the present systems and/or methods and should not be construed as limiting the appended claims to any particular embodiment or group of embodiments. The specification and drawings are accordingly to be regarded in an illustrative manner and are not intended to limit the scope of the appended claims. In interpreting the appended claims, it should be understood that the word comprising does not exclude the presence of other elements or acts than those listed in a given claim; the word a or an preceding an element does not exclude the presence of a plurality of such elements; any reference signs in the claims do not limit their scope; several means may be represented by the same or different item(s) or implemented structure or function; any of the disclosed devices or portions thereof may be combined together or separated into further portions unless specifically stated otherwise. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage. In particular, all working combinations of the claims are considered inherently disclosed.

LIST OF ITEMS

[0070] 1 pore pressure monitoring device [0071] 2 sensor cavity [0072] 4 pressure sensor [0073] 6 sensor cavity fluid [0074] 8 gas pressure equalisation/discharging route [0075] 10 de-gassing means [0076] 12 gas-fluid filter means [0077] 13 fluid-solid filter means [0078] 14 gas discharge means [0079] 16 inner lumen [0080] 18 gas permeable membrane [0081] 20 projecting portion of the hydrophobic gas filter means [0082] 22 closed distal end portion [0083] 24 atmosphere connection means [0084] 26 sensor cavity housing [0085] 27 cone tip [0086] 28 fluid filter means [0087] 30 data connection means [0088] 32 data receiving means [0089] 34 protection means [0090] 36 bore [0091] 37 part of the housing providing a bore. [0092] 38 coupling devices [0093] 40 ground/soil matrix [0094] 42 atmosphere