Abstract
Apparatus and method of treating soil. The apparatus is a movable vehicle having a blade device for removing the soil. The removed soil is transferred into a loading space in which the soil is homogenized. One or more binders are mixed to the soil, after which it is taken back to ground by a spreading device. Stabilization of the soil is thus carried out in the movable apparatus.
Claims
1. An apparatus for treating soil, which apparatus is a movable vehicle and comprises: a blade device for removing the soil from ground surface; a loading space for receiving the removed soil; a transfer device for transferring the removed soil into the loading space; a feeding device for feeding at least one binder into the soil; a mixing device configured to mix the soil in the loading space; and a spreading device for spreading the binder-treated soil back to the ground surface from where it was removed by the blade device; wherein the apparatus is configured to feed to the soil at least one activator material which is together with the soil being treated configured to form a hardenable geopolymeric or alkali-activatable mixture.
2. The apparatus according to claim 1, wherein the blade device comprises a cutting blade, which blade configured to scrape a portion of a selected depth off the ground surface by effect of movement between the vehicle and the ground surface.
3. The apparatus according to claim 1, characterized in wherein the mixing device comprises a plurality of movable blades and is configured to crush the removed soil in the loading space.
4. The apparatus according to claim 1, wherein the feeding device is arranged in connection with the spreading device, whereby the binder is fed after mixing of the soil.
5. The apparatus according to claim 1, wherein the apparatus comprises at least one container for the binder.
6. The apparatus according to claim 1, wherein the apparatus is intended for road layer stabilization, wherein soil materials of a load-bearing structure of the road are homogenized and stabilized.
7. A method of treating soil, in which method: soil is treated with at least one binder to improve its compression strength; and the soil is treated in a movable apparatus; wherein a load-bearing structure of a road is stabilized to a compression strength of at least 0.1 MPa by using as the binder an activator which forms together with road aggregate a hardenable geopolymeric or alkali-activatable mixture.
8. The method according to claim 7, wherein homogenization and stabilization treatment of the load-bearing structure of the road are performed in the movable apparatus.
9. The method according to claim 8, wherein soil is removed by a movable removing device and the removed soil is transferred into a loading space of the movable apparatus; the removed soil is treated by a mixing device of the movable apparatus for its homogenization; at least one binder is fed to the soil; and the removed soil is returned back to ground after the treatment by a spreading device.
10. The method according to claim 7, wherein layer stabilization is performed for the road by removing soil of the road in a layer of a predetermined thickness and by treating the removed layer by providing it with binder to increase the compression strength of existing soil.
11. The method according to claim 7, wherein composition of the road aggregate is analysed and the binder and dosage of the binder to be used are selected based on the analysis.
12. The method according to claim 7, wherein at least one industrial side-stream material or product prepared from a side-stream material is mixed into the soil in the movable apparatus.
13. The method according to claim 8, wherein the stabilization treatment is performed for an edge portion of the road by means of the movable apparatus.
Description
SHORT DESCRIPTION OF THE FIGURES
[0083] Some embodiments of the proposed solution are illustrated in more detail in the following figures, in which
[0084] FIG. 1 is a schematical and simplified diagram presenting different layers of a road structure,
[0085] FIG. 2 is a schematical and simplified diagram presenting a composition of one binder-stabilized structural layer,
[0086] FIG. 3 is a schematical and simplified diagram presenting some additional features and components which may be included in a stabilized structural layer,
[0087] FIG. 4 schematically illustrates a cross-section of one road structure as seen from a longitudinal direction of the road,
[0088] FIG. 5 schematically illustrates a cross-section of one road structure and its edges as seen from a longitudinal direction of the road,
[0089] FIG. 6 schematically illustrates one stabilized structural layer with reinforcements as seen from a longitudinal direction,
[0090] FIGS. 7 and 8 schematically illustrate some apparatuses for stabilizing soil as seen from the side,
[0091] FIG. 9 is a schematical and simplified diagram presenting features of yet one apparatus used for stabilization, and
[0092] FIG. 10 is a schematical and simplified diagram presenting features relating to analysis of soil.
[0093] For clarity reasons, some embodiments of the proposed solutions are illustrated in the figures in a simplified form. The same reference numbers are used in the figures to refer to the same elements and features.
DETAILED DESCRIPTION OF SOME EMBODIMENTS
[0094] As seen in FIG. 1, a road structure 1 typically comprises a subsoil 2 over which a pavement structure 3 of the road is provided. The pavement structure 3 comprises a plurality of successive layers 3a which may include a surface layer 4, a base layer 5, a sub-base layer 6 and a drainage layer 7. There may be fewer of more of the structural layers 3a depending on the circumstances. The structural layers 3a may be as known per se in structure and properties. One or more of these structural layers may be treated with a hardenable binder to stabilize the structural layer. This is referred to as a so-called layer stabilization.
[0095] In FIG. 2 it is presented that a stabilized structural layer 8 comprises a hardenable binder 9 by which stone material 10 of the structural layer 8 is reinforced. The stone material 10 may be for example sand, gravel, broken stone, crushed material or the like. The stabilized material or mass may further be applied in a space delimited by a sleeve structure 11. The sleeve structure 11 may be a tubular structure. Alternatively, the stabilized structural layer may be applied over or between one or more filter fabrics or earth construction films.
[0096] FIG. 3 lists additional features which may be included in the binder-stabilized structural layer. As mentioned above in this document, the stabilized mass may comprise a fibre reinforcement 12 and the mass may be foamed 13. Further, for example a geopolymer or an alkali-activatable mixture 14 may be used for the stabilization of the stone material. Additionally, a filler 15 may be mixed in the mass and its strength may be improved by using separate reinforcement elements 16. The mass may be electricity-conducting 17 and storing. The stabilized mass may be applied between, over or under protective layers 18, which protective layers may be a tube or a sleeve structure, a filter fabric and various other films and wovens. Further, various inserts 19 such as, for example, technical installations, devices, sensors, cables, anchoring elements and coupling elements may be arranged in the stabilized mass and structure. Thermally insulating material, paste or paint may be applied to the surface of the structure.
[0097] FIG. 4 illustrates one road structure 1 in which the binder-stabilized structural layer 8 is the base layer 5 over which a levelling layer 20 is further applied. The levelling layer 20 may be a protective layer or a layer that enables shaping of the road surface and protects the stabilized layer 8. The levelling layer 20 may be crushed material. On top there is a surface layer 4 which may be crushed material, oil gravel, concrete or asphalt. Under the structural layer 8 there may be the normal sub-base layer 6 and drainage layer 7 which are part of the pavement structure 3 and of course the subsoil 2 under the pavement structure 3. Further, the stabilized structural layer 8 may be arranged in a space delimited by a sleeve structure 11. The sleeve structure 11 may protect the structural layer 8 against moisture stress and it may be a type of geotube that participates in shaping the cross-section of the structural layer.
[0098] FIG. 5 illustrates one road structure 1 having a binder-stabilized structural layer 8 in its pavement structure 3. Additionally, the edges of the road structure 1 are also provided with binder-stabilized edge portions 8c, 8d. These edge portions 8c, 8d may form the embankment or shoulder of the road structure and may thereby speed up the construction of the road and facilitate road maintenance. Further, the edge portions 8c, 8d may be provided with a ready ditch profile 21 or ditch beam, technical installations 22 or supports 23. The technical installations 22 may be for example conductors, measuring devices and fixing elements. The supports 23 may be for example elements intended for supporting and fixing railings, lampposts, traffic signs and the like. Further, the edge portions 8c, 8d may be provided with integrated or separate extension portions 8e which also comprise a binder-stabilized structure. The counter embankment of the road structure may be supported and construction of the road speeded up by means of the extension portion. Further, maintenance of the road may be facilitated and safety improved when vegetation at the edges of the road may be prevented.
[0099] FIG. 6 illustrates a binder-stabilized structural layer 8 having a plurality of longitudinal reinforcement elements 16 arranged to its base P side. Due to bending, the base P side of the structure is subject to tensile stress that is well absorbed by the reinforcements 16. The reinforcements 16 may have a desired profile and they are fixed to the surrounding hardened mass.
[0100] FIG. 7 illustrates an apparatus 24 for treating a structural layer of a road structure 1 or any ground soil. The apparatus 24 comprises a movable vehicle 25 having a blade device 26 for removing the soil from the surface of the road structure 1 or ground while the apparatus 24 is being moved in a driving direction A. The blade device 26 may be for example a milling machine. Alternatively, the blade device 26 comprises a cutter plate 26a which is pushed into the soil while the apparatus 24 is moving and removes the soil by scraping. The soil may be cut for example to a depth of 200-400 mm. The removed soil is transferred into a loading space 28 of the apparatus by a transfer device 27, which loading space is provided with a mixing device 29. The mixing device 29 may not only mix the soil but also crush its larger constituents, such as stones. The mixing device 29 may comprise a plurality of movable blades 29a. The transfer device 27 may be a conveyor or an inclined surface. A feeding device 30 is configured to feed one or more stabilizing materials into the soil. The apparatus 24 may comprise one or more containers 31 for the stabilizing material. After mixing and homogenization, the mass may be transferred by means of conveyors 32 and 33 from the loading space 28 to a spreading device 34 which spreads the mass onto the ground surface as a structural layer having a desired layer thickness and width. The mass may be compacted by means of a vibrator V.
[0101] As seen in FIG. 7, the binder or binder mixture being used in the stabilization may be fed from a feeding device 30 into the loading space 28, from a feeding device 30a to the conveyor 33 or from a feeding device 30b to the spreading device 30b.
[0102] For analysis of the soil to be removed, the apparatus 24 may comprise a sensor S1 and an optical measuring device 35 or a camera. In connection with the loading space 28 there may be a sensor S2 to identify properties of the mass and the soil. Sensors and measuring devices may also be arranged in connection with the transfer device 27 and the conveyors 32, 33. The measurement data are transmitted to a control unit CU of the apparatus 24. Alternatively or additionally, measurement data may also be transmitted to one or more external control units CU', servers or electronic terminal devices.
[0103] The apparatus 24 may comprise a feeding device 36 for feeding a film, fabric, geotube or the like together with the stabilized mass. Further, the apparatus 24 may comprise a feeding device 37 for feeding reinforcements or cables onto the ground surface together with the mass.
[0104] FIG. 8 illustrates another apparatus 24 having a slightly different construction than the scraper vehicle illustrated in FIG. 7. However, the main components and the operating principle are the same. The difference is that after mixing, the mass is fed from the loading space between two films 38a, 38b. In this case, the spreading device 34 comprises film feeding devices 39a, 39b and a coupling device 40 for joining the edges of the films to each other. Alternatively one film is used, the longitudinal edges of which film are guided to the upper surface side of the mass and coupled to each other. In both cases, the spreading device 34 feeds the tubular structure along the conveyor surface 32 onto the surface of ground. The tubular structure is a geotube or sleeve structure 11 which protects the stabilized structural layer 8.
[0105] FIGS. 7 and 8 further introduce a foaming device 41 by which the mass may be foamed to reduce its density.
[0106] FIG. 9 further lists the features of one apparatus 24. The apparatus differs from those illustrated in FIGS. 7 and 8 in that the blade device 26 comprises a boom and a bucket. The boom may be movably coupled to the chassis 25 of the apparatus 24 and different buckets may be coupled to its outer end. The blade device 26 may thus be the boom of an excavator.
[0107] FIG. 10 presents the stages, devices and features relating to analysis of the soil being treated. These aspects have already been described above in this document.
[0108] Although the invention is illustrated in the figures in relation to a road structure, the apparatus is also suitable for other earth and foundation construction. Several examples of this have been introduced under short description of the invention of the specification.
[0109] The figures and their description are only intended to illustrate the idea of the invention. However, the scope of protection of the invention is defined in the claims of the application.
