METHOD FOR FORMING A BULKHEAD SEALED WITH MORTAR AND THE BULKHEAD MANUFACTURED THEREBY AND THE TONGUE-AND-GROOVE ELEMENT FOR THE BULKHEAD The present invention relates to a method for forming a bulkhead sealed with mortar by driving a number of bulkhead elements principally of metal into soil, the elements comprising an elongated tongue, the lower end of which is at least partly closed with a tip element, an elongated groove and a web connecting these parts, whereupon the tongue and groove are attached to each other by first registering either one of them to the other and by then pushing them in the longitudinal direction into an interlocking position within each other, and by feeding mortar or a similar substance at least to an area limited by the groove. The invention also relates to a tongue-and-groove element for a bulkhead in soil, and to a bulkhead including a number of such tongue-and-groove members which comprise an elongated tongue the lower end of which is at least in part closed by a tip element, and an elongated groove and a web connecting these, the tongue and groove being of metal and nested in the bulkhead, so that from a tongue of a specific tongue-and-groove element inside a groove, the web extends to the groove of the tongue-and-groove element through the longitudinal slot in this groove.

In excavation, various kinds of bulkheads are used as abutment walls in banks, dock or similar structures and, on the other hand, in environmental technology, as an underground dam wall for restricting the flow of waters, for example, in polluted soil. A supporting wall has to bear the load of soil on its other side, the other side being partly open, while a dam wall may be covered by soil on both sides, the emphasis then being in compactness. The bulkhead may comprise a tubular pile and connection elements, which in this case usually are open profiles, such as overlapping C and T profiles welded over the whole length to the opposite sides of a pile tube of a large diameter. Such structures have been described in a magazine article by Raimo Soininen:"Terasputket paaluina ja pontteina" (Steel tubes as piles and sheet piles), Rakennustekniikka 6/1984, pp 471-474. As sealing methods for such tongue-and-groove joints are in the first place known from the publication JP- 4179725 disclosing the filling of a groove element with fibres strongly absorbing water and the swelling of fibres with water in a direction transverse to the tongue- and-groove joint before inserting the tongue into the groove; and in the second place, from the publication JP-55105023 disclosing the later insertion of flexible steel sheets in the slots of the tongue-and-groove joint inside a tongue-and-groove tube and thereafter the feeding of suitable mortar inside the tongue-and-groove tube.

In the first case, there is the problem of fibres moving during the insertion of the

tongue-and-groove joint, the problem in the latter case being that the cavity for mortar is filled with soil when driving the pile into soil. Further, sealing requires special materials and several stages of operation. In both cases, mortar is only found inside the tongue and groove as a seal so that the exterior surface of the bulkhead thus formed is always entirely of bare metal in relation to the surrounding soil, which may cause corrosion problems.

From the publication US-5,782,583 it is known to form bulkhead elements by bending them from sheets, the elements comprising a web plate, one of the opposite sides of which including a groove formed from a sheet and the other side including a tongue formed from a sheet, which typically are parallel. The publication EP- 0 628 662 discloses similar bulkhead elements, which have been manufactured by hot shaping. As described above, the grooves include a longitudinal slot or a wider opening through which the tongue extends inside the groove. The publication mentioned first discloses a scraper attached to the lower end of the groove for removing soil that has fallen into the groove, while the latter publication describes a rivet or piece fastened to the lower end of the groove for preventing soil from blocking the groove. The publication EP-0 628 662 further discloses a separate tube extending along the whole length of the groove and placed inside it; this tube prevents soil from falling into the tongue and groove, and it may further be used for rinsing the tongue and groove and feeding sealing material into the tongue-and- groove joint. This tube is removed and it may be used again for the same purpose in later tongues and grooves. Correspondingly, the publication US-5,782,583 discloses the rinsing of a tongue-and-groove joint with water after its parts have been inserted into soil, and then the feeding of sealing material into the joint by an injection tube.

These solutions have the disadvantage that soil is first pushed into the groove driven to soil, due to which it is necessary to rinse the tongue and groove with water, which considerably adds to the installation time and costs. Also in both these cases, mortar is only found inside the tongue and groove as a seal so that the exterior surface of the bulkhead formed is always entirely of bare metal in relation to the surrounding soil, which may cause corrosion problems.

The publication WO-95/30056 discloses a bulkhead, each piling element of stainless steel of which consists of several tubes, which are fastened to each other with connection plates, and one tube at the edge of the piling element is of a smaller diameter than the other tubes of the element. The piling element also includes a base comprising a sheet piece of a width of the element; the lower edge of the base is either straight, or it forms an acute angle of, for example, 90° or 60°. In addition to

this, the lower edges of all the tubes and the possible length extensions of the tubes include an injection ring in the interior of the tube provided with a number of upwards directed holes. Near its lower edge, the edge tube of lower diameter is provided with a guide cutter cutting longitudinal slot to the larger tube as the smaller tube is pushed inside the bigger tube of the adjacent element. Thus, the bulkhead is extended in the horizontal direction by taking a thinner tube inside the larger tube, while at the same time cutting a longitudinal slot required by the connection plate to the wall of the larger tube. On the other hand, the publication also discloses other kinds of tongues and grooves, which are used as the thickness of the material exceeds 4 mm; in this case, the tongue is not a tube, but solid material. According to the method of this publication, the piling element is first driven to soil into the final and desired piling depth, and only then mortar is injected into the holes of the injection ring so that mortar is only found around the injection holes and thus possibly only at the lower ends of the tubes as material concentrations. According to the publication, the mutual sealing of adjacent piling elements is carried out during piling because of the elasticity of the stainless steel material of the larger pipe cut open by the guide cutter as the larger pipe is tightly pressed on the smaller tube or, alternatively, by using a rubber seal. The piling element of the publication is expensive, and the longitudinal cutting of the wall of the larger tube during piling increases the necessary impact strength; this requires special parts, which thus have been described in the publication.

The publication US-5 388 931 discloses a modular wall consisting of plastics, the edges of the modules of which on the one hand comprise an internal tube and, on the other hand, an external tube provided with a longitudinal slot. The lower end of the internal tube comprises holes, and the lower end is open. The modular wall is arranged to soil by digging a pit of desired depth using an excavator and by pumping it full with a mixture of water and bentonite, which prevents the pit edges from collapsing. While the mixture of water and bentonite has not yet hardened, a plastic module is hoisted into the pit by using a crane and a steel plate, the spikes of which are pressed into the holes of a plastic plate connecting the internal tube and the external tube; as the module is in the pit, the steel plate used as help is removed.

Finally, the interior of the internal tube and the space between it and the external tube is rinsed with a cleansing liquid flowing through the openings in the interior tube and/or through the open lower end, after which barrier material, such as mortar, is pumped into the points in question. Such a solution and the use of plastic material is possible, because the mounting is carried out into a very loose mixture of water and bentonite, i. e. which is in a flowing state, and not into actual soil. If one is being

exact, the bulkhead of the publication is not located in soil, but in prearranged bentonite mixture. Also, the strength of the plastic bulkhead is not nearly sufficient in all embodiment tarets. Digging a pit according to the publication is time consuming and expensive, and it is not even possible to do it in every place.

The first object of the invention is to provide a method and structural parts for producing such a waterproof bulkhead at least partly made of metal, which may be used both as a supporting wall and a dam wall and which would have a sufficient strength in various localities. The second object of the invention relates to such a bulkhead and to a method for forming it, in which method the blocking of that part of the tongue-and-groove joint driven first into soil can be prevented as well as possible, and thus it is possible to drive the second counterpart of the tongue-and- groove joint into soil without any problems to form a connection with said first counterpart. The third object of the invention relates to such a bulkhead and a method, with which the tongue-and-groove joint can be made proof against leakage by simple measures and by using inexpensive materials. The fourth object of the invention relates to such a bulkhead and a method, in which the structural parts can be shaped and measured as freely as desired for each specific purpose. The fifth object of the invention relates to such a bulkhead and a method, with which one or both sides of the bulkhead, for example, made of steel, can be made to resist corrosion better than a bare metal surface, when necessary, and at least in some uses. The sixth object of the invention relates to such a bulkhead and a method, which would also have sufficient friction in relation to soil, when necessary.

The above described drawbacks may be eliminated and the above defined objects may be realized with a method of the present invention, which is characterized in what is defined in the characterizing part of claim 1, and with a tongue-and-groove element of the invention, which is characterized in what is defined in the characterizing part of claim 8, and with a bulkhead of the invention, which is characterized in what is defined in the characterizing part of claim 17.

Surprisingly enough, it has now been noted that by arranging the tongue part of a tongue-and-groove joint in a bulkhead of such a pile tube, the lower end of which is provided with a collar of a large diameter formed by the pile shoe and with a relatively long tip element projecting from the collar to the push direction of the pile, i. e. downwards, and by arranging the output of the hardening substance from the interior of the pile tube through holes above the collar and the contact point of the pile tube, a tongue surrounded by hardening substance is produced from this pile tube into soil so that the groove can be later driven to place around the tongue and

into said surrounding hardening substance without problems. In the arrangement of the invention, the tongue of each tongue-and-groove joint is in soil before the respective groove, thus deviating from the above described techniques. Further, the substance sealing the tongue-and-groove joint is spread into place at the same time as a part of the bulkhead wall is driven into soil, and no additional steps are necessary to bring it into position. The hardening hydrous substance is effectively and fast transferred from the interior of the metal tongue through the holes into the cavity formed by the collar around the tongue and groove merely by the action of the into soil driving impacts and/or driving vibrations of the pile. Thus, the groove is then driven into this hardening substance along the tongue so that the substance remains as a seal between the tongues and grooves and to surround the groove.

When according to the invention, in every structural part or element of the bulkhead comprising a tongue, a groove and a web, which can have various forms, connecting these, the groove is arranged sufficiently near the tongue by using a narrow web, and the entire wall may be covered by the hardening substance and later by the hardened substance, which improves corrosion resistance.

The invention is next described in more detail referring to the enclosed drawings in which Figs. 1A-IE are schematic views of the first steps of the method of the invention, when using a tongue-and-groove element of the first embodiment of the invention and there a pile shoe provided with a long tip element in longitudinal section perpendicular to the ground level, corresponding to the line I-I in Fig. 2B; Figs 1F-1H are respective schematic views to Figs. 1A-1E of third steps of the method of the invention, in which the tongue-and-groove element of the invention is extended in vertical direction with a similar tongue-and-groove element, while at the same time driving the extended bulkhead element deeper into soil; Figs. 11-1L are respective schematic views to Figs. 1A-1H of second steps of the method of the invention, in which the tongue-and-groove element is extended in horizontal direction with similar tongue-and-groove elements, while driving the extending tongue-and-groove element deeper into soil, and of a part of bulkhead thus produced in soil; Figs. 2A and 2B show schematically a part of a finished bulkhead achieved by a tongue-and-groove element of the second embodiment of the invention driven into

soil in a vertical section along the line I-I of Fig. 2 in respect to the ground level and, respectively, in a horizontal section along the line II-II in Fig. 2; Figs. 3A-3B is a schematic vertical section perpendicular to the ground level along the line III-III in Fig. 4 of the first and third steps of the method of the invention, in which a tongue-and-groove element according to the third embodiment of the invention comprising a groove, a tongue provided with a pile shoe, and a principally tubular web, is driven into soil and extended in horizontal direction with similar tongue-and-groove elements, at the same time as the extending tongue-and-groove element is driven deeper into soil; Fig. 4 is a schematic horizontal section along the line IV-IV in Fig. 3B in direction of the ground level of a part of a finished bulkhead achieved by tongue-and-groove elements according to the third embodiment of the invention; Fig. 5A is a more detailed longitudinal section along the line VI-VI in Fig. 5B of the first embodiment of the tongue-and-groove element of the invention, comprising a tongue, a flat web and a pile shoe connected to the tongue, and alternative connections for the tongue and groove for achieving length extensions; Fig. 5B is a more detailed cross-section along the line V-V in Fig. 5A of the first embodiment of the tongue-and-groove element of the invention, the tongue inside the groove being shown in dashed lines; Fig. 6A is a longitudinal section along the line VII-VII in Fig. 6 of a preferred embodiment of the tongue-and-groove element of the invention, comprising a groove, a flat web and a pile shoe connected to the tongue, and a mortar tube provided with a pile shoe in the web, so that the position of the tongue deviates from the position of the groove; Fig. 6B is a cross-section along the line VIII-VIII in Fig. 6A of a second preferred embodiment of the tongue-and-groove element of the invention; Fig. 7A is a longitudinal section along the line IX-IX in Fig. 7B of a fourth embodiment of the tongue-and-groove element of the invention, comprising a groove, a flat web and a pile shoe connected to the tongue. and several mortar tubes without a collar in the web; Fig. 7B is a cross-section of the fourth embodiment of the tongue-and-groove element of the invention along the line X-X in Fig. 7A;

Fig. 8 is a respective cross-section to Fig. 5B of a fifth embodiment of the tongue- and-groove element of the invention, making it possible to form an angle to the bulkhead; and Fig. 9 is a respective cross-section to Fig. 6B of a sixth embodiment of the groove- and-tongue element of the invention, with which it is possible to form an angle to the bulkhead.

The tongue-and-groove element 1 for a bulkhead in soil comprises a generally elongated tongue 3 or longitudinal bead closed at the lower end by a tip element 11 and an elongated groove 2 or longitudinal bead and a web 4 connecting the tongue and the groove. The web 4 may generally be of any type, which may contain sections of different types. In the following, the tongue-and-groove element is usually referred to with the reference number 1, when it is not necessary to separate the different tongue-and-groove elements from each other; alphabets are additionally used, when horizontally adjacent tongue-and-groove elements la, lb, lc, etc. are separated from each other, and footers, when vertically sequential <BR> <BR> <BR> tongue-and-groove elements 1, 12, 13, etc., or a combination of these characters, i. e.<BR> <BR> <BR> <BR> generally la,... N, lbl. N, etc. The same notation is also applied to other reference numbers, when necessary. The tongue and the groove consist of metal, i. e. typically steel, and they nest in the longitudinal direction. According to the invention, the tongue 3 is hollow comprising a tongue tube 7K with a casing or wall 18 closed over the main part of the length, and the groove 2 is also hollow comprising a groove tube 6* with a prefabricated longitudinal slot 8 extending substantially through the entire length of the tongue and groove; the width W4 of the longitudinal slot is at least equal to, but generally slightly larger than the thickness W5 of the web 4.

However, the width W4 of the prefabricated longitudinal slot 8 in the groove is substantially smaller than the outer diameter D2 of the tongue 3 and thus of the <BR> <BR> <BR> tongue tube 7K so that the tongue inside the groove cannot come loose in the transverse direction to the longitudinal direction Ll of the tongues and grooves.

Roughly taken, a groove principally of the type of a C profile and a tongue of the type of a T or P profile is generated, although the cross-sectional shape of the <BR> <BR> tongue and groove tubes 7K and 6* may vary within large limits. Generally, it is most preferable to use tubes with a circular cross-section, as in the figures, but it also is possible to use tubes of oval or angular cross-section. Preferably, the cross-sectional shapes of the groove and the tongue are principally similar so that the space between them may be kept relatively small. Such a tongue-and-groove combination is assembled so that, in accordance with the invention, the groove 2 of the next

tongue-and-groove element 1 is positioned in line with the tongue 3 of the tongue- and-groove element 1 in soil M; then the groove 2 is pushed onto the tongue in the longitudinal direction LI of the tongues and grooves so that it sets around the tongue. Such a tongue-and-groove joint also endures forces in all directions transverse to the length Ll of the tongues and grooves without coming loose. The web connecting the tongue and the groove is formed at least of a sheet section 9 in direction of the said tubes, and of possible tubes, which will be described in more detail later.

The tongue-and-groove element further comprises a pile shoe 5 or 5* merely at the lower end of the tongue 3, or possibly a mortar tube 7L in a way which will be described later, the pile shoe comprising a longitudinal tip element 10 and a collar 12, the maximum diameter Dl of which is larger than the tongue 3 or the outer diameter D2 of the tongue tube 7K, and flow apertures 17 opening from the interior 13 of the tongue 3 or the tongue tube 7K above the collar 12 for outflow of mortar B.

The above mentioned possible position points for the pile shoe indicate that the lower end of the groove 2 does not have a pile shoe, but the tongue tube 6* forming the tongue opens downwards, i. e. to soil. For the tongue 3, the theories are applied which have been presented in the non-public patent application FI-982699 by the same applicant. In this case, the feeding of mortar around the tubular pile during installation described in connection of the previous invention is utilized; additionally, the guiding tip element 10 of the pile facilitates the direct progress of the bulkhead element into soil M at the same time as the tubular pile itself works as the male connection element i. e. tongue 3, and the female connection element i. e. groove 2 is able to advance in mortar B surrounding the tongue without problems.

After mortar B has hardened, it forms a strengthening filling in the interior 13 of the tongue, a sealing substance filling the space 40 between the tongue and the groove, and a layer 4 la surrounding and protecting the groove. In some cases, in addition to the tongue and the groove, the bulkhead element 1 comprises a mortar tube or <BR> <BR> <BR> mortar tubes 7L, 7LB which are arranged between the tongue tube 7K and the groove tube 6* and which are all substantially parallel. The pile shoe 5 thus comprises a closed longitudinal tip element 10, the length L2 of which is at least five times the outer diameter D2 of the tube in question, and flow apertures 17, which pass through the pile shoe 5 and/or the connection element 14 described later and/or the wall 16,18 of the tongue tube 7K. Thus the tongue 3 or the tongue tubes 7K, and also <BR> <BR> <BR> the possible mortar tubes 7L, are substantially or totally closed at least directly downwards, i. e. towards soil, as the flow apertures 17 preferably open outside these tubes above the collar 12 of the pile shoe, as is described in more detail later.

Typically, the tongues are closed below the widest point R of the collar 12 of the pile shoe. In the embodiment in Fig. 5A, the flow apertures 17 pass through the wall 16 of the connection element 14; in the embodiment in Fig. 6A, the flow apertures <BR> <BR> 17 pass through the walls 18 of the mortar tube 7L and the tongue tube 7K and<BR> <BR> <BR> <BR> <BR> likewise through the wall 18 of the tongue tube 7K in Fig. 7A. In the embodiment in Figs. 7A-7B, the mortar tubes 7LB contain no flow apertures, but entirely solid tubes, which are filled with mortar B and, when necessary, with reinforcements, such as concrete reinforcements 37 for achieving strong columns bracing the bulk element 1.

According to the invention, the outer diameter D3 of the tip element 10 is at most equal to the outer diameter D2 of the pile tube, and the tip element consists of a metal bar, as in Figs. 6A-6B, or a metal tube, which may be a section of the connection element 14, as in Figs. 5A-5B, or it may be formed of a section of the tongue tube 7K or the mortar tube 7L provided with a collar or the mortar tube 7LB with no collar, as in Figs. 7A-7B. Thus, the distance L2 between the point R corresponding to the maximum diameter D1 of the collar 12 and the lower end 38 of the tip element is at least five, but preferably at least seven, and possibly ten times the outer diameter D2 of the pile tube. At the point of the lower end 38 or somewhere else below the flow apertures 17, the tip element 10 of the tongue 3 is closed either by the tip element 11, or it is closed by the collar 12 or the metal bar or connection element 14 acting as its extension. Similarly, the mortar tubes 7LB are closed by the tip element 11. The collar 12 comprises an outer surface 19 narrowing or tapering at least partly towards the lower end 38, which, when driven into soil, seals the collar, making it thus possible to generate a relatively stable cavity T around the tongue for mortar B and for the groove to be brought in later. The flow apertures 17 typically open outside to the tongue 3 in radial directions and above the widest point R of the collar. Here, the definitions above, above and below, respectively, and below, refer to the relative location in the position of the bulk element so that the latter definition describes the direction coming to soil M and the former the direction towards the ground, no matter whether the ground is horizontal or oblique, or whether the tongue-and-groove element 1 lies straight or inclined in relation to the ground.

The collar 12 comprises a thorough hole 36, the diameter D6 of which is at least nearly equal to or larger than the outer diameter D3 of the tip element for passing through of the mortar tube/tongue tube 7K, 7L or the connection element 14 acting as its extension. The possible connection element 14 is located between the mortar

tubei'tongue tube 7L, 7K and the collar 12, and it extends from above the collar to below thereof, and its upper diameter D4 is bigger than the lower diameter D3. i. e. the outer diameter of the tip element, and the connection element 14 comprises a stop face 27, the upper diameter D4 of which is bigger than the diameter D6 of the collar hole 36 for supporting against the upper surface 28 of the collar. The collar 12 then loosens downwards from the connection element 14 so that the groove 2 or tongue 3 of the bulkhead element lb,. N of the tongue-and-groove element brought to soil later, or its collar or tip element, pushes the loosening collar of the tongue- <BR> <BR> and-groove element la, N previously driven into soil M in front along the tip element 10 and, when necessary, off it, which makes it possible to set the installation depth, as can be seen in Fig. 1L. The connection element 14 or the collar 12, respectively, comprises connection elements 26-for fastening the lower end of <BR> <BR> <BR> the tongue tube or the mortar tube 7L, 7K to it. The fastening with the elements 26 may be carried out either to a sleeve facing the groove, as in Fig. SA, or to a pin facing the tongue, as in Fig. 6A. In the situation mentioned first, the inner diameter of the sleeve is equal to or slightly smaller than the outer diameter D2 of the tongue 3, and in the latter case, the outer diameter D8 of the pin is equal to or slightly larger than the inner diameter of the tongue 3 for achieving a tight crimp connection. The connection may still be secured by a slot 39 receiving the end of the tongue, the principle of the slot having been described in the earlier patent FI-81415 by the same applicant. This slot is shown in Fig. 6A, but it may also be applied to the embodiment in Fig. 5A. Preferably, the collar 12 comprises an upwards-lifted outer edge 25 so that an upwards opening recess 15 surrounding the mortar tube/tongue tube 7K, 7L is formed. The connection elements 26 may also comprise welds, rivets, pins, screws, bolts, etc. not shown in the figures for securing the fastening between the tongue and the connection element or the collar.

The tongue tube and the mortar tube, respectively, comprise at the upper end an opening/openings 29 for feeding liquid mortar B into the interior 13 of the tube in question; the opening 29 may simply comprise an upper end of the tongue 3 which is open either at the moment of feeding the mortar B, or it may be continuously open. It is also possible to use aggregates or an adapter, which are known in themselves or new, such as bends or similar parts, with which mortar B may be fed into the interior 13 of the tongue at the same time as the force F driving the tongue- and-groove element into soil M is directed to the upper end of the tongue.

Correspondingly, the tongue tube 7K, and possibly the mortar tube 7L, comprises at its lower end flow apertures 17 opening above the collar 12, but otherwise the

tongue tube and the mortar tube are at their lower ends closed by the tip element 11 or the collar 12.

In the groove 6 or the groove tube 6* of the tongue-and-groove element 1 of the invention, the said longitudinal slot 8 extends over the entire length of the groove, and the inner diameter D7 of the groove tube is substantially larger than that of the tongue tube 7K or the largest outer diameter D2 or D4 or D8 of its possible extension pieces. Thus, there is a distinct space 40 between the groove and the tongue, as can be seen in Figs. 2B, 4 and 5B. The groove tube 6* then fits to push onto the tongue 3 or the tongue tube 7K in the longitudinal direction LI so that mortar B is not pushed away from the space 40, but it remains in place and forms a seal for the tongue-and-groove joint after hardening.

The tongue 3 and the groove 2 are permanently connected to each other with the web 4, consisting principally of a straight or curved metal sheet section 9, or a section containing bends. In the Figs. 5A-6B and 8 and 9, there are straight sheet sections 9, while the Figs. 7A-7B contain both straight, curved and winding sections in an exemplary way. The sheet section or sheet sections 9 of the web 4 are typically fastened both to the outer surface of the tongue tube and the groove tube by longitudinal connections 31, as weld connections. The tongue, the groove and the web as such may also be manufactured as one piece by casting or extrusion, such as tubes, but this way the parts will probably become too expensive, and there will probably also occur technical difficulties in the manufacture. Normally, it is most preferable to use steel as metal. Further, or alternatively, the web 4 principally consists of one or several pile tubes 20, which are attached to the adjacent pile tubes 20 and/or tongue tube 7K and the groove tube 6* by metal sheet sections 9 and longitudinal connections 31. For example, the pile tube 20 may be a metal tube 21 open from both ends, the diameter D9 of which is in most cases bigger than the diameter D2 of the tongue or bigger than the diameter D10 of the groove, as can be seen from Figs. 3A-4. When piling with force F, the interior of such an open pile tube 21 fills the soil at least in part with material, but with it a very rigid bulkhead wall 30 is easily achieved, although in this case, part of the bulkhead will not <BR> <BR> <BR> covered by a mortar layer. The said pile tube 20 may also be a mortar tube 7L, which comprises at its lower end a pile shoe 5* consisting of the above described longitudinal tip element 10 and collar 12 and flow apertures 17, which open from the interior 13 of the mortar tube above the collar 12 for the outflow of mortar, as is shown in Figs. 6A-6B and 9. Such a mortar tube is usable in a situation, in which the bulkhead 30 has to be made entirely covered by the mortar layer 41a, 41b and

41c, as is shown in Figs. 2A-2B. As a third alternative, the said pile tube 20 may also be a mortar tube 7LB comprising at its lower end only the tip element 11 closing the mortar tube, but no flow apertures for mortar; such a mortar tube may be filled with mortar B and possible concrete reinforcements 37, but it will not be coated with mortar.

In order to make the bulkhead 30 entirely coated with the mortar layer 41 a, 41b and 41c, the distance between the groove and the tongue in each tongue-and-groove element 1 or, in case of a solution with a mortar tube, the distance between the groove and the mortar tube, and between the mortar tube and the tongue, as well as between the collar/collars, and the diameter/diameters, respectively, have to fulfill the following conditions. The distance Wl between the central lines 32 of the mortar tubes 7L with collars and/or the distance Wl between the central lines 32,33 of the tongue tube 7K and the mortar tube 7L have to be at least equal to the maximum diameter Dl of the collar in this direction. Alternatively in tongue-and- groove elements without collars, the distance W2 between the central line 33 of the tongue tube 7K and the nearest point of the outer surface 34 of the groove 6* has to be at most equal to the maximum diameter of the collar in this direction. Further, the outer diameter D10 of the groove tube 6* has to be smaller than the maximum diameter D of the collar 12. With these conditions, the mortar layer 41a, 41b, 41c generated by the collar/collars of the tongue-and-groove element forced into soil M above them is sufficient to surround the groove 2 and the web 4, and to fill the space 40. The steel material of the tongue-and-groove elements 1 and thus of the entire bulkhead 30, with the exception of the tongue-and-groove element la driven into soil first or of the groove 2 of the bulkhead elements lal N extended in the longitudinal direction LI, will be protected, for example, against corrosion.

When a straight bulkhead 30 is needed, the longitudinal slot 8 of the groove in bulkhead elements 1 consisting only of a tongue 3 and a groove 2 is arranged on the opposite side of the groove tube 6 as the tongue, for example in a way which can be seen in the Figs. 2B, 4,5B, 6B and 7B. If the shape of the web 4 deviates from straight and if it has been attached in the groove and/or tongue elsewhere as on the connecting level of their central lines 42,32, the longitudinal slot 8 is respectively located at the deviating place. When angles are needed in the bulkhead 30, for example, a longitudinal slot 8 is arranged to another point on the circumference of the groove 2, or the web 4 is fastened to another point on the circumference of the groove 2. In Figs. 8 and 9 such tongue-and-groove elements 1 are shown for achieving right outer angles or inner angles, but it has to be understood that other

angles may be formed by placing the longitudinal slot 8 or the web 4 to another point. In the tongue-and-groove elements in Fig. 9, the tongue 3 is arranged to the <BR> <BR> side of the mortar tube 7L joined by the sheet section 9 of the second web 4*, the width W3 of the second web 4* forming a predetermined angle K1 in relation to the distance Wl between the first tongue and the groove 6 away from the second tongue. Alternatively, in the groove, the level formed by the tongue-and-groove slot 8 and the central line 42 is at an angle K2 in relation to the distance W2 between the central line 33 of the tongue 3 and the outer surface 34 of the groove tube 6.

As a form for the tongue-and-groove element 1 there is in Fig. 6A shown a solution, in which the pile shoe 5 of the tongue, more precisely said its widest point R is lies a distance L3 lower than the lower edge of the groove 2 for changing the installation depth in a way which is indicated in Fig. 2A. This form of implementation is needed when the collar 12 is not loosening in the previously described way, but it is necessary to cover the tongue-and-groove elements entirely covered with mortar B at the same time as it has to be possible to at least maintain the immersion depth S 1 of the tongue-and-groove elements. In this case, the above described small distance W2 between the groove and the tongue of the tongue-and-groove element 1 causes that the tip element 10 or at least the collar 12 of the adjacent bulkhead element ., driven into soil later hits the collar 12 of the bulkhead element la,... N driven into soil earlier so that the lower end 38 of the tongue-and-groove element lbN, driven into soil later would remain on an upper level than the lower end of the previous tongue-and-groove element/elements, which may be of disadvantage. By providing the bulkhead 30 with the above described tongue-and-groove elements of a specific type at required intervals, it is possible the make their lower end 38 to either remain at the average desired depth S1 or to sink down into the desired depth SI, depending on the distance L3. With a high value for the distance L3, the installation depth for the bulkhead can be increased as the installation of the wall advances, and with a lower value, the installation depth may be kept on average unaltered; then it naturally has to be taken into account that also the density of the placing of the special bulkhead elements changing the installation depth in the bulkhead changes the average installation depth S 1 Apart from the said parts, longitudinally successive tongue-and-groove elements li, <BR> <BR> <BR> 12, ils, 14, and extension pieces 23 or splice joints 22 connecting these tongue-and- groove elements are used for producing higher bulkheads 30. The extension pieces 23 may be internal or external sleeves, on or correspondingly inside of which the ends of the groove tubes 6* and/or tongue tubes and/or mortar tubes 7K, 7L, 7LB

and/or other pile tubes 20 extending each other are set, as can be seen in Figs. 5A and 7A. These sleeve connections carried out by the extension pieces 23 are preferably made by following the principles described in the earlier patent FI-81415 by the applicant. Such a connection may also be secured or locked by using rivets, screws or welds between the groove tube/tongue tube/mortar tube/pile tube and the extension piece, as is described in the earlier non-public patent application FI- 982699 by the applicant. It is also possible to use a splice joint achieved by the welds between the said tubes. At least the successive tongues 3a,. N, 3b,. N, 3cl.. N, etc. are connected to each other by these extension pieces or splice joints, and the <BR> <BR> grooves 2al N, 2bl N, 2Ct.. N, etc. to each other, and the possible pile tubes 20ai N, 20b,... N, 20c,.. N, etc. to each other. It is generally not necessary to fasten the sheet sections 9 of the webs 4,4* to each other, at least in the case when the entire bulkhead wall is covered by the mortar layer 41a-c but, when necessary, the sheet sections 9 of the webs extending each other may, for example, be welded to each other.

A bulkhead 30 sealed with mortar is formed by driving into soil M a number of bulkhead elements 1 mainly of metal, which in practice usually is steel, so that the tongue and the groove adhere to each other by first directing either one of them as an extension for the other, and then by pushing them in the longitudinal direction LI into an overlapping position in relation to each other, and by feeding mortar or a similar substance at least to an area limited by the groove. According to the invention, first of all, a tongue-and-groove element 1 of a type described above is used, and secondly, action is taken in the way described below. In the first step, the tongue-and-groove element la or lai is driven into soil M by the pulsating force F, either by using a block of big mass or vibration, and then the interior 13 of the tubular tongue is filled with mortar B and the tongue-and-groove element is further driven deeper into soil M with the pulsating force F so that mortar transfers as a flow V through the flow apertures 17 around the tongue 3 into a cavity T made by the pile shoe 5 in soil. Thereafter, mortar B is added into the interior 13 of the tongue either alternately or simultaneously with the driving of the tongue-and- groove element further into soil with the pulsating force F, until the said tongue- and-groove element la or la, has been driven into soil either entirely or almost entirely, according to need. At the same time, a mortar zone has been formed around the tongue, the diameter D 11 of the zone being larger than the outer diameter D10 of the groove. This first chain of steps has been shown in more detail in Figs. 1A- IE, and generally in Fig. 3A. If the total length L4 of one tongue-and-groove element is sufficient for the height of the bulkhead 30, the first tongue-and-groove

element lies at the desired installation depth S 1 so that next the step three is adopted, in which the groove 2 of the next corresponding tongue-and-groove element lb or 1 b i is arranged at the point of and in line with the tongue 3 of the previous tongue- and-groove element lal, after which the next adjacent tongue-and-groove element lb or 1 b is driven into soil M by directing to it the pulsating force F driving into soil, either alternately or simultaneously with the adding of said mortar B into the interior 13 of the tongue, at the same time as a tongue-and-groove joint is formed between the elements, as the groove is directed along with the tongue of the tongue- and-groove element driven into soil first. This is continued, until also this tongue- and-groove element lies at the desired installation depth SI. Depending on the dimensioning of the tongue-and-groove element, the tip element 10 or the collar 12 at the lower end of the tongue of the latter tongue-and-groove element hits the collar of the element driven into soil first at the final stage of installation, as in the cases shown in Figs. 1L and 2A, and, according to the above described structure of the tip element of the tongue-and-groove element, the pile shoe 5 of the latter element either detaches the collar 12 of the former tongue-and-groove element or, alternatively, the forcing of the latter element into soil is stopped. The installation of the second element is stopped here. This third chain of steps is shown in more detail in Figs. 1 I-1 L, and generally in Fig. 3B.

The width of the bulkhead is added in the horizontal direction by arranging the groove 2 of each succeeding tongue-and-groove element Ic, ld, etc., around the upper end of the tongue 3 of the previous tongue-and-groove element lb, and these next adjacent tongue-and-groove elements lc, ld, etc. are driven into soil M by directing the pulsating force F driving into soil to each element for its part either alternately or simultaneously with the adding of said mortar B into the interior 13 of the tongue. A tongue-and-groove joint is then built always between two horizontally adjacent tongue-and-groove elements, the tongue guiding the groove around it.

Depending on the type of the tongue-and-groove element 1, the pulsating force F may be directed only to the web 4, such as the pile tube 20 in accordance with Figs.

3A and 3B so that the force F may easily be used simultaneously with the adding of said mortar B without accessories. If again, because of the type of the tongue-and- groove element 1, the pulsating force F is directed directly to the tongue 3, i. e. to its upper end, the force F is used either alternately with the adding of mortar B, as in Figs. 1A-1L, or, if a previously mentioned aggregate or adapter is used, simultaneously with the adding of mortar B.

If the entire length L4 of one tongue-and-groove element is not sufficient for the height of the bulkhead 30, the said first step or the said third step, respectively, is continued by a second step in the following way. The first tongue-and-groove <BR> <BR> element la, at least partly driven into soil M or the next tongue-and-groove elements 1 b I, l c l, etc. connected to it by a tongue-and-groove extension are extended with a second tongue-and-groove element la2 or with second tongue-and- groove elements lb2, Ic2, ld2, etc. by using splice joints 22 or extension pieces 23.

The tongue-and-groove element thus extended is driven further into soil by using the said pulsating force F and the adding of mortar B into the interior 13 of the tongue, either alternately or simultaneously, as has been described above. These steps are described in more detail in Figs. IF-11. When necessary, the first and the next adjacent tongue-and-groove elements are vertically extended each in turn with new tongue-and-groove elements la3, lb3, lc3, etc., and the tongue-and-groove element thus extended is further driven into soil by using the said pulsating force F and the adding of mortar B into the interior 13 of the tongue, until the tongue-and- groove elements lie at the desired depth Sl. The final result of these steps can be seen in Figs. 1L and 2A.

As generally is defined, the driving of each tongue-and-groove element or the <BR> <BR> <BR> tongue-and-groove element combinations la,.. N, lb,,.. N, 1CL N, etc. extended with extensions in the longitudinal direction is continued into soil M, until the tip element 10 of the lowermost tongue-and-groove elements lal, lbl, lcl, etc. reaches the intended depth Sl in soil M. When the adjacent two tongue-and-groove elements la and lb, lb and lc, lc and Id, etc. interlocked with each other by a tongue-and- groove joint have reached the desired final depth, the mortar B is let to harden around the groove, between the groove and the tongue, and in the interior 13 of the tongue 3, thus resulting in a finished bulkhead 30. Between shifts or at other times, depending on the situation, slowly hardening mortar B can be used. The bulkhead can be closed as a circle so that the last tongue is hit to the groove hit into soil first by using a collar, the maximum diameter D1 of which is smaller than the inner diameter D7 of the groove. Another alternative is to rinse clean the groove inserted into soil first and to install the tongue with mortar to it.

In the method of the invention, mortar B can be fed into the interior 13 of the tongue without substantial overpressure. As already has been mentioned, the pulsating force F is generated by impacts and/or vibration, and its maximum value is such that a pressure impact occurs in the interior of the pile tube, which is at least 10 bar and preferably at least 15 bar. The mortar used is concrete based mass, i. e. a mixture of a

hydraulically hardening binding agent, a filler, such as stone material, and water; or cement based mass, i. e. a mixture of hydraulically hardening binding agent and water; or bentonite based mass, i. e. a mixture of bentonite and water.

When using tongue-and-groove elements in which the tip element or collar of the previous element hits the non-loosening collar of the previous element, the lower end of the bulkhead 30"grows"upwards. If it is desired to keep the lower end of the wall continuously at a certain depth S1, an adjacent tongue-and-groove element with a tongue lowered by the distance L3, such as a tongue-and-groove element of Figs.

6A-6B, is struck inbetween. According to what has been described, i. e. unless the purpose is to keep the whole bulkhead covered with mortar B, it is clear that no mortar tube or mortar tubes 7L according to Figs. 8 or 9 are needed in the tongue- and-groove element provided with a lowered tongue. Analogically with this, according to plan or need, tongue-and-groove elements according to Fig. 8 or Fig. 9 or elements forming an angle deviating from these may be struck at certain points of the bulkhead between the previous and later tongue-and-groove elements, i. e. positioned horizontally side by side, these elements being likewise extendable in the longitudinal direction LI as the other tongue-and-groove elements. The webs 4,4* of the tongue-and-groove elements of the bulkhead may, if using wide sheet sections, be formed in a desired way to be stiffening or, for example, bearing the one-side load of soil by using curvatures, wave forms, or other suitable shapes, as is in an exemplary way shown in Figs. 7A-7B. The shapes are not limited to the ones shown.

In the bulkhead 30 of the invention, the interior 13 of the tongue and the space 40 between the tongue and the groove is thus substantially filled with mortar B, and at least the grooves 2 are covered by the mortar layer 41a. Further, in a preferred embodiment, but not necessarily, the webs 4 of each tongue-and-groove element are covered by an integrated mortar layer 41b together with the mortar layer 41a covering the successive grooves 2. When necessary, the bulkhead 30 comprises separate mortar tubes 7L, in which case preferably, but not necessarily, both the mortar tubes and the webs 4 connecting them to each other and/or to the tongues or grooves are covered by an integrated mortar layer 41c. The bulkhead consists of <BR> <BR> <BR> several tongue-and-groove elements la,... N, lbl N, lcl 5t, etc. arranged to extend each other horizontally and/or vertically, and in the bulkhead, at least the tongues and/or pile tubes 3,20, and in most cases, also the grooves 2 are connected with extension pieces 23 or splice joints 22 in the vertical direction, i. e. in the longitudinal direction of the bulkheads. The mortar B used is concrete based mass or cement based mass or bentonite based mass. Due to the rigidity of the bulkhead, for example, polluted or otherwise removable soil may be transported away, and the mortar pile wall may be left as an edge for the excavation.