Method for carrying out a sheet piling underneath an existing wall and associated device

Abstract

 Method for installing a sheet piling underneath an existing wall or the like (1), whereby the sheet piling of a primary fraction of the wall (1) comprises the steps of excavating soil such that a volume is freed underneath the wall or the like (1), of putting one or several U-shaped revetment parts (4) in place, characterised in that at least one of the U-shaped revetment parts (4) comprises two side walls (5,6) which, when erected, are releasably connected to a partition (7) situated between both side walls (5,6).

Description

[0001] Method for installing a sheet piling underneath an existing wall.

[0002] Sheet-piling a wall mainly consists in deepening a wall and/or foundation.

[0003] Such deepening may for example be required when parking lots or other useful areas are to be provided under an existing building construction.

[0004] It is clear that such an operation should be performed with the necessary precautions and expertise.

[0005] When installing a sheet piling, the wall is divided in fractions having a length of for example 1 metre to 1,50 metres.

[0006] Non-adjacent fractions are provided with a deepened wall part with a proper foundation, further also called the primary fractions, in a first stage. In a second stage, the intermediate fractions or secondary fractions are sheet-piled in a similar manner.

[0007] There are different methods for elaborating each deepened wall fraction, but it is clear that some soil must always be excavated, that an appropriate revetment must be provided, that a reinforcement and a formwork must be provided and that the boxed footings and walls in the revetted space must be concreted.

[0008] BE 1,011,109 describes a method for installing a sheet piling under an existing bearing wall or wall.

[0009] The method mainly consists of the following subsequent steps.

[0010] Against the wall or partition to be sheet-piled is placed, per column or fraction, a box-shaped element, in jargon as well as further also called box, with three closed sides and one open side, whereby the latter is directed towards the bearing wall or wall.

[0011] Soil is removed from within the box which is put on the ground, as a result of which the box sinks, and practically at the same time soil is removed from under the wall to be sheet-piled in the extension of the box, all of this step by step.

[0012] Each excavation and sinking of the box corresponds for example to a depth of 50 cm, in practice the height corresponding to a modular fraction of the height of the box.

[0013] In the space created under the bearing wall or wall is introduced a U-shaped revetment part with its open side towards the box.

[0014] Next, the U-shaped revetment parts are temporarily secured to the vertical edges of two sides of the box.

[0015] The excavation and other steps are repeated. The U-shaped revetment parts sink along with the box. Another U-shaped revetment part is applied in a similar way over the last applied and sunken U-shaped revetment part.

[0016] Thus, U-shaped revetment parts are piled.

[0017] These operations are repeated until the desired depth is reached.

[0018] An enlarged foundation slab is laid on the ground, or squeezed through, under the bottommost U-shaped revetment part.

[0019] A lost form board is secured to the open front side of each of the U-shaped revetment parts, and the bolts between the U-shaped revetment parts and the box are removed.

[0020] The concrete is poured in the thus created formwork.

[0021] The spaces between two adjacent columns are encased in the same manner as described above.

[0022] As soon as the poured concrete has sufficiently hardened, all box-shaped elements piled on top of one another are progressively pushed up, with hydraulic means.

[0023] Each of the columns is built according to a sequence whereby a column having identical or similar dimensions is formed between two already finished columns.

[0024] The walls of the U-shaped revetment parts belonging to two neighbouring columns and serving as lost formwork are used as lateral form parts to that end.

[0025] On the backside of the intermediate column to be formed are applied vertical sheets having a width which is somewhat larger than the width of the column to be formed and a height equal to that of the U-shaped revetment parts.

[0026] This sheet is manually slid with its outer edges behind the already formed U-shaped revetment part, after which the created formwork space is finished in the same manner as described above with sheets which are secured with their edges to the neighbouring U-shaped revetment parts.

[0027] Note that when applying this known method, short reinforcing bars are inserted through holes in the lateral side walls of the U-shaped revetment parts, all of this in view of a good coupling of the subsequent fractions. In addition, conventional reinforcement irons are provided in each column.

[0028] This known method has some major disadvantages.

[0029] It is clear that the U-shaped revetment parts are a significant drawback to the intended monolithic structure.

[0030] Indeed, application of the method as described in BE 1,011,109 results in columns which are mainly separated from one another by the left U-shaped revetment parts, which are usually made of steel.

[0031] The present invention aims to remedy one or several of the above-mentioned and other disadvantages.

[0032] To this end, the present invention concerns a method for installing a sheet piling under an existing wall or the like, whereby non-adjacent primary fractions of the wall or the like are sheet-piled in a first stage, and intermediate fractions or secondary fractions are provided in a second stage, whereby the sheet-piling of a primary fraction comprises the steps of excavating soil, such that a volume is freed underneath the wall or the like or underneath a foundation footing which may be present, providing one or several U-shaped revetment parts, whereby at least one of the U-shaped revetment parts comprises two side walls which, when erected, are releasably connected to a partition situated between two side walls.

[0033] A major advantage which is thus obtained is that both side walls can be easily removed when the secondary fractions are manufactured, and that a monolithic structure can thus be obtained, i.e. that the primary and secondary sheet piling fractions are maximally bonded chemically.

[0034] The present invention also concerns a device for installing a sheet piling under an existing wall or the like, which device is characterised in that it comprises a mainly flat wall part of which at least one edge is provided with a U-shaped profiled channel of which at least one end is bounded by an end stop.

[0035] The advantages of this specific embodiment will become clear from the following detailed discussion with reference to the figures.

[0036] In order to better explain the characteristics of the present invention, the following preferred method and associated device for installing a sheet piling under an existing wall according to the invention are described by way of example only without being limitative in any way, with reference to the accompanying drawings, in which:

figures 1 to 12 schematically represent the steps of the method for installing a sheet piling under an existing wall according to the invention;

[0037] Figures 1 to 10 initially illustrate how, according to an aspect of the method according to the invention, a primary sheet piling fraction is manufactured.

[0038] Figure 1 schematically represents the wall 1 to be sheet-piled with a foundation footing 2, and seen as a section.

[0039] In addition is also represented a box 3 to be put up, which here, prior to being placed, is provided with a first U-shaped revetment part 4a.

[0040] A box 3 is the term used in the art for a U-shaped bent slab or thus composed slab elements, usually made of steel.

[0041] Such a box 3 thus usually comprises three walls, i.e. a back 3A, and two side walls 3B and 3C, and an open side situated against the back 3A which, when in use, is directed towards the wall 1 to be sheet-piled.

[0042] Figure 1 shows, at a height above the foundation footing 2, the ground level before any excavation is performed, by means of a dotted line G, and at a height under the foundation footing 2, by means of a dashed line S1, the volume of sand that, after digging to the bottom side of the foundation footing 2, is additionally excavated before the box 3, coupled to the first U-shaped revetment part 4a, is put in an initial position of use.

[0043] This initial position of use is represented in figure 2 and is characterised more specifically by the precise positioning of the first U-shaped revetment part 4a under the foundation footing 2.

[0044] The method continues with the further excavation of a volume of sand in accordance with the dashed line S2, the sagging or sinking down of the box 3 with a first U-shaped revetment part 4a, and the insertion and coupling of a second U-shaped revetment part 4b.

[0045] The result is represented in figure 3.

[0046] By way of example, this sequence of steps is repeated two more times, with the result as represented in figure 4, i.e. four piled U-shaped revetment parts 4a to 4d under the foundation footing 2 and a box 3 sunk along in proportion.

[0047] According to the invention and as represented in more detail in figure 5, each U-shaped revetment part 4 comprises two side walls 5 and 6 which, when put in position, are disengageably connected to a partition 7 situated between both side walls 5 and 6.

[0048] The partition 7 is a prefabricated reinforced concrete slab 8 in this case, for example having a width of 151 cm and a height of 40 cm. The reinforcement 9 is provided in the core of the actual concrete slab 8, here in the shape of a concrete mesh, as well as extending outside said concrete slab 8, here in the shape of lattice girders, at least on one side thereof.

[0049] Each of the side walls 5 and 6 comprises in particular a mainly flat wall part 5A and 6A having a height H, substantially in accordance with the height of the concrete slab 8, and a width B which is larger than the width of the foundation footing 2.

[0050] On one of the standing edges, as represented in more detail in figure 6, more specifically the standing edge 10 to be put under the wall 1 to be sheet-piled in a position of use, each side wall 5 and 6 is provided with a U-shaped profiled channel 11 whose dimensions are adapted to the geometry of the concrete slab 8, such that it can be inserted in the latter in an appropriate manner.

[0051] Indeed, the U-shaped profiled channel 11 makes it possible to slide a concrete slab 8 in it.

[0052] In order to prevent any undesired sliding out, each of the channels 11 are bounded here by an end stop 12.

[0053] Note that for the first U-shaped revetment part 4a, the end stops 12 are provided at the bottom, whereas for the other U-shaped revetment parts 4b and so on, the end stops 12 are provided at the top. Naturally, it is possible to provide an end stop 12 on both far ends, i.e. at the bottom and at the top.

[0054] On the other opposite standing edges 13, more specifically the standing edges 13 leaning on the box 3 in a position of use, each side wall 5 and 6 is provided with coupling means 14, here in the shape of passages, for coupling the side walls 5 and 6 to the box 3 which is also provided to that end with associated coupling means 15 through which for example bolts may be provided.

[0055] Whereas in the steps of the method according to the invention as discussed above, there was talk about inserting and coupling a second and/or subsequent U-shaped revetment part 4b, what precedes allows to illustrate how this is preferably performed.

[0056] One can start from an already assembled side wall 5 with a partition 7, in particular the concrete slab 8 whose protruding part of the reinforcement 9 points in the direction of the coupling means 14.

[0057] This assembly, or the composing parts thereof, can be provided on site under the wall 1 to be sheet-piled, and possibly the side wall 5 will be coupled to the box 3 at this stage, after which the other side wall 6 is provided in an appropriate manner, i.e. with the U-shaped profiled channel 11 such that it encloses the side edge of the concrete slab 8, more specifically with the end stop 12 on the top side thereof. This side wall 6 is coupled to the box 3 as well.

[0058] Further excavation and sinking proceeds without any undesired upward sliding of the concrete slabs 8 thanks to the end stops 12.

[0059] When the aimed depth is reached, as represented in figure 4, after applying four piled U-shaped revetment parts 4 under the foundation footing 2 and a box 3 sunk along in proportion, the steps for providing an enlarged footing 16 may also be gone through if necessary.

[0060] For this purpose, mainly just sand will be excavated from underneath the first U-shaped revetment part 4a situated at the bottom, and possibly a revetment will be provided to limit the volume.

[0061] The dimensions of the enlarged footing 16 result from the technical calculations. One and another is illustrated in figure 7.

[0062] In a next step, as represented in figures 8 and 9, recyclable spacers 17 are provided against the side walls 5 and 6 of the currently piled U-shaped revetment parts 4.

[0063] These recyclable spacers 17 consist of two wooden beams 18, here provided vertically up to the concrete slabs 8. It is clear that, as an alternative, the spacers 17 can also be made of concrete or a synthetic material.

[0064] The section of these recyclable spacers 17, in this case the beams 18, is for example rectangular with a width of 12 cm and a thickness of 4 cm.

[0065] On each of these recyclable spacers 17, more specifically on the side directed towards the opposite spacer 17, are then provided prefabricated reinforced concrete beam elements 19 or what are called coupling reinforcement boxes, for example by nailing.

[0066] The prefabricated reinforced concrete beam elements 19 are provided with a reinforcement 20 which may extend from the core of the beam element 19 to the outside, and this on both coupling walls 21 of the beam element 19.

[0067] The coupling walls 21 in this case concern the two opposite walls 21, one of which is directed towards the recyclable spacer 17 and the other towards the opposite spacer 17.

[0068] The prefabricated reinforced concrete beam elements 19 are preferably prefabricated in such a manner that the parts of the reinforcement 20 extending outside the core are bent in a compact manner to near or against the coupling walls 21 of the beam element 19.

[0069] Optionally, and preferably, one of the coupling walls 21, including the downward bent reinforcement parts 20, is protected by a removable liner, which lined coupling wall 21 is mounted against the spacer 17.

[0070] The parts of the reinforcement 20 extending outside the core which are still visible and accessible then, i.e. the bent reinforcement parts near or against the coupling walls 21 of the beam element 19 which are directed towards the opposite concrete beam elements 19, are folded out in the direction of the opposite concrete beam elements 19.

[0071] Next or previously is provided a reinforcement mesh 22, preferably coupled to the protruding parts of the reinforcement 9 of the concrete slab 8 and/or to the parts of the reinforcement 20 extending outside the core of the concrete beam elements 19.

[0072] In a subsequent step, as illustrated in figure 10, a formwork 23 is provided on the open side of the U-shaped revetment parts 4 directed towards the box 3, i.e. between the two side walls 5 and 6 of the U-shaped revetment part 4.

[0073] The formwork 23 may be composed of mainly flat slabs, or alternatively, as applied in the embodiment as discussed and as shown, of prefabricated reinforced concrete slabs 8B, mainly corresponding to the concrete slabs 8 and thus to the associated reinforcement 9B.

[0074] In the last applied variant, the concrete slabs 8B are part of the monolithic structure, and thus these concrete slabs 8B are put in line with the intended front wall of the sheet piling with their flat wall, which is situated opposite the wall provided with the protruding parts of the reinforcement 9B.

[0075] When flat slabs are used, they are put up in such a manner that the side directed towards the revetment to be manufactured is placed in line with the intended front wall of the sheet piling. This requires an appropriate sizing of the recyclable spacers 17.

[0076] Indeed, the formwork elements 23 are placed on top of one another from bottom to top by each time placing each element 23 against the recyclable spacers 17, in which position they are temporarily secured by means of struts 24.

[0077] At the height of the upper U-shaped revetment part 4d, however, the formwork is installed in a different manner.

[0078] A front slab or slide 25 secured in a slanting manner, which as shown here extends in front of and above the foundation footing 2, provides for a hopper 26. This slide 25 is also called overflow formwork in jargon.

[0079] Now that the entire volume of the sheet piling fraction has been revetted, the concrete can be poured and vibrated.

[0080] After appropriate curing, for example after a day, the front slab or slide 25 can be removed and the excess concrete can be cut off.

[0081] By thus providing primary sheet piling fractions, for example at an intermediate distance which mainly corresponds to the width of each sheet piling fraction, a stable basis is obtained for sheet-piling the intermediate wall fractions after said curing.

[0082] It should be noted that the primary sheet piling fractions are preferably realised in two sub-phases of the primary phase, one and another such that the treated fractions are maximally removed from one another.

[0083] If the fractions were numbered from 1 to 14 for example, the fractions 1, 5, 9 and 13 would be treated in the first phase, followed by fractions 3, 7 and 11.

[0084] The same applies for the secondary phase described below, whereby the secondary fractions are preferably realised in two sub-phases.

[0085] In the logic of the example cited, the fractions 2, 6, 10 and 14 are realised first in the secondary phase, and finally the fractions 4, 8 and 12.

[0086] The following steps of the method are illustrated in figures 11 and 12, seen in plan view here for clarity's sake.

[0087] Figure 11 shows two semi-finished primary sheet piling fractions seen in plan view, provided at a distance from one another, and represented left and right in the figure.

[0088] In order to manufacture the intermediate or secondary sheet piling fraction, the earth should be removed step by step, in layers of for example 40 or 50 cm.

[0089] All of this is carried out between the two boxes 3, which are still on the spot and in line with the leaning primary sheet piling fractions.

[0090] Temporary struts 24 are provided in the box if necessary.

[0091] According to an aspect of the invention, the two side walls 5 and 6 of the U-shaped revetment part 4 are subsequently detached and recycled.

[0092] This can be easily done by disconnecting the bolts, provided through the passages 14 and 15 in the side walls 5 and 6 on the one hand, and the box 3 on the other hand.

[0093] Subsequently, the simple inward tilting of the side walls 5 and 6 results in the release of the U-shaped profiled channel 11 and the side wall 5 or 6 concerned.

[0094] Next, a prefabricated reinforced concrete slab 8C is placed behind the concrete slab 8 leaning left and right.

[0095] Preferably, this is done by first putting one side edge thereof behind for example the left leaning concrete slab 8, namely by putting the concrete slab 8C so deep behind the concrete slab 8 that the second opposite edge can be put alongside and subsequently behind the right leaning concrete slab 8.

[0096] To this end, the width of said prefabricated reinforced concrete slab 8C must be somewhat wider than the distance between the left and right leaning concrete slabs 8.

[0097] Alternatively, this prefabricated reinforced concrete slab 8C is placed exactly between the left and right leaning concrete slabs 8 and fixed there in an appropriate manner, for example by resting on a leaning edge of the primary sheet piling fraction.

[0098] To this end, the width of such a prefabricated reinforced concrete slab 8C should mainly correspond to or be somewhat smaller than the distance between the left and right leaning concrete slabs 8.

[0099] In this phase is also provided a secondary back revetment 27, for example wooden beams or a metal slab, behind the left and right leaning backs 3A of the leaning boxes 3 which were dug in during the manufacture of the primary fractions.

[0100] The above steps with respect to the secondary fractions are repeated step by step until the desired depth is reached.

[0101] Next, an enlarged footing 16 is provided if need be, mainly in accordance with the method for the primary fractions.

[0102] In a subsequent step, the recyclable spacers 17 are removed from both leaning primary fractions.

[0103] As a result, the removable lining provided on the downward bent reinforcement parts 20 is released for removal, after which the downward bent reinforcement parts 20 or the so-called guard reinforcement can be folded out in the direction of the opposite concrete beam elements 19 which had already been provided in the primary fractions.

[0104] The following steps of the method according to the invention are strongly analogous to the corresponding steps for manufacturing the primary fractions.

[0105] In short, what it comes down to, is that a reinforcement mesh 22 is provided, preferably coupled as previously explained, a formwork 23 is provided on the open side currently directed to the box 3 of the currently partly revetted volume under the existing wall 1.

[0106] The formwork 23 may be composed of mainly flat slabs or, alternatively, as applied in the embodiment as discussed and as shown, of prefabricated reinforced concrete slabs 8D, mainly corresponding to the concrete slabs 8B and thus to the associated reinforcement 9D.

[0107] In the last applied variant, the concrete slabs 8D are part of the monolithic structure, and thus these concrete slabs 8D are put in line with the intended front wall of the sheet peeling with their flat wall, which is situated opposite the wall provided with the protruding parts of the reinforcement 9D.

[0108] Displacement in the direction of the volume to be confined, i.e. in the direction of the concrete slab 8C, can be prevented by providing support elements in the volume to be confined, or by providing the concrete slab 8D with a shoulder on the visible side, incorporated or provided on the spot.

[0109] If flat slabs are used, they are placed such that the side directed towards the revetment to be manufactured is in line with the designed front wall of the sheet piling.

[0110] Such flat slabs can be placed against the currently visible side of the leaning primary fractions.

[0111] Whatever formwork 23 one chooses, the formwork elements 23 are placed on top of one another from bottom to top and maintained in their position by means of struts 24 resting against the secondary back revetment 27 or against the leaning boxes 3.

[0112] At the height of the upper U-shaped revetment part 4d, the formwork is installed in a different manner in view of providing a slide 25 and a hopper 26, all of this mainly in accordance with the above-described method.

[0113] Also pouring the concrete, vibrating it, making it partly cure and cutting it off are mainly in accordance therewith.

[0114] Thus are manufactured the secondary sheet piling fractions, having as a major feature that they form an actual monolithic structure with the primary fractions.

[0115] Naturally, the struts 24 will have to be removed in an appropriate manner, if necessary also the flat slabs of the formwork 23, the secondary back revetment 27 and that of the boxes 3, and the dug pit will have to be filled again, one and another after providing the necessary bracing if need be, for example by means of ground anchors.

[0116] It should be noted that no unused lost formworks are implemented, i.e. all form parts are either recycled or integrated in a chemically bound and/or mechanically connected manner in the actual sheet piling.

[0117] It is clear that the quality of the sheet piling is considerably improved by maximally preventing soil from ending up in the volume to be concreted in all steps of the method according to the invention.

[0118] The present invention is by no means restricted to the embodiments described by way of example and represented in the figures; on the contrary, such a method for installing a sheet piling under an existing wall and an associated device according to the invention can be made in many different shapes and dimensions while still remaining within the scope of the invention.

Claims

1. Method for installing a sheet piling underneath an existing wall or the like (1), whereby in a first phase, non-adjacent primary fractions of the wall or the like (1) are sheet-piled, and in a second phase intermediate fractions or secondary fractions are provided, whereby the installation of the sheet piling of a primary fraction comprises the steps of excavating soil, such that a volume is freed underneath the wall or the like (1) or underneath a foundation footing (2) which may be present, providing one or several U-shaped revetment parts (4), characterised in that at least one of the U-shaped revetment parts (4) comprises two side walls (5,6) which, when erected, are releasably connected to a partition (7) situated between both side walls (5,6).

2. Method according to claim 1, characterised in that the partition (7) is a prefabricated concrete slab (8).

3. Method according to claim 2, characterised in that the prefabricated concrete slab (8) is provided with a reinforcement (9) in the core of the actual concrete slab (8) as well as extending outside this concrete slab (8), at least on one side thereof.

4. Method according to claim 1, 2 or 3, characterised in that each of the side walls (5,6) comprises a mainly flat wall part (5A,6A), whereby one of the standing edges, when installed, more specifically the standing edge (10) to be put under the wall to be sheet-piled in a position of use, is provided with coupling means which can work in conjunction with the side edges of the partition (7).

5. Method according to claim 4, characterised in that the coupling means concern a U-shaped profiled channel (11) whose size is adapted to the geometry of the side edges of the partition (7), one and another such that it can be applied in the latter in an appropriate manner, for example by sliding it in.

6. Method according to claim 5, characterised in that the U-shaped profiled channel (11) is bounded tight by an end stop (12) on at least one far end, one and another so as to prevent any sliding out along the far end concerned.

7. Method according to one or several of the preceding claims, characterised in that after one or several of the U-shaped revetment parts (4) have been put in place, spacers (17) are provided against the side walls (5,6) of one or several piled U-shaped revetment parts (4).

8. Method according to one or several of the preceding claims, characterised in that after one or several of the U-shaped revetment parts (4) have been put in place, and possibly after spacers (17) have been put in place which can be provided against the side walls (5,6) of said one or several piled U-shaped revetment parts (4), prefabricated reinforced concrete beam elements (19) are provided directly against the side walls (5,6) or on each of the recyclable spacers (17).

9. Method according to claim 8, characterised in that the prefabricated reinforced concrete beam elements (19) are provided with a reinforcement (20) extending from the core of the beam element (19) to the outside, and this on two opposite walls thereof, called the coupling walls (21) of the beam element (19).

10. Method according to claim 9, characterised in that the prefabricated reinforced concrete beam elements (19) are prefabricated such that the parts of the reinforcement (20) extending outside the core are folded in a compact manner near or against the coupling walls (21) of the beam element (19), of which preferably one of the coupling walls (21), including the downward bent reinforcement parts (20), is protected by a removable lining, which lined coupling wall (21) is mounted against the side wall (5,6) or the spacer (17).

11. Method according to one or several of the preceding claims, characterised in that after one or several of the U-shaped revetment parts (4) have been put in place, a formwork (23) is provided between the two side walls (5,6) of the U-shaped revetment part (4), more specifically at a distance from the partition (7), which formwork (23) comprises one or several prefabricated reinforced concrete slabs (8B).

12. Method according to one or several of the preceding claims, characterised in that the installation of the sheet piling of a secondary fraction between two primary fractions comprises the steps of excavating soil in view of making accessible the side walls (5,6) as used when manufacturing the leaning primary fractions, and when detaching and recycling the side walls (5,6).

13. Method according to claim 12, characterised in that one or several prefabricated reinforced concrete slabs (8C) are provided behind or between the left and right leaning concrete slabs (8).

14. Method according to claim 13, characterised in that any possible spacers (17) are removed from both leaning primary fractions, and in that the removable lining provided on the downward bent reinforcement parts (20) is removed, after which the downward bent reinforcement parts (20) or so-called guard reinforcement is folded out in the direction of the opposite concrete beam elements (19) which had already been provided in the primary fractions.

15. Method according to claim 12, 13 or 14, characterised in that a formwork (23) is provided on the currently open side, which formwork (23) comprises one or several prefabricated reinforced concrete slabs (8B).

16. Device for installing a sheet piling under an existing wall or the like (1), characterised in that it comprises a mainly flat wall part (5A,6A) of which at least one edge is provided with a U-shaped profiled channel (11), of which at least one far end is bounded by an end stop (12).

Drawing