MXPA96006320A - Channeling of flu circulation - Google Patents

Abstract

The present invention relates to a fluidized pressure flow conduit, comprising a tubular enclosure (1) bounded by a thin wall (1) and fixed on a rigid support slab (2) in molded material. According to the invention, the upper part (12) of the enclosure (1) is constituted, in a straight section by at least three thin-walled segments, two lateral segments (3,3 ') each extending between a lower side (31) and an upper side (32) respectively, and at least one upper segment (4) closing the enclosure (1) that is connected to the upper sides (32, 32 ') of the side segments (3, 3') and each The thin-walled side element (3,3 ') is associated with a rigid support element (5, 5') in molded material fixed at its base to the corresponding side of the slab (2) and comprising an internal face (51, 51). ') turned towards the enclosure (1) which has a profile conjugated to that of the lateral segment and on which it is applied, said internal face (51, 51') of the slab (2) extending to a level (H2) sufficient to maintain the rigidity of said lateral segment throughout its height (H1) without risk of subsidence

Description

CHANNELING OF FLUID CIRCULATION The invention relates to the realization of conduits of very large sections, particularly for the transport of a fluid subjected to an important pressure which can, for example, exceed ten bars. The invention is especially applicable to the construction of forced ducts for hydroelectric plants, of water adduction or sanitation circuits, but it can also be applied to the transport of pressurized gas, for example to gas pipelines or to district heating circuits. Generally, a large section duct consists of an elongated tubular enclosure that can be made of a molded material, such as concrete, or with metal, and when the duct has to withstand strong internal pressure, it is advantageous to make it from metal because it can then be constituted by several juxtaposed relatively light panels, easy to maintain, which can be welded together to form a closed tubular enclosure which generally has a circular section and which resists particularly well to the traction effects generated by the Application of internal pressure Forced ducts, used in hydroelectric installations, are generally carried out in this way, however, the duct must normally rest on the ground, usually by means of spaced points, support points and, although the resistance What it offers when subjected to internal pressure is good, however, has a tendency to deform in absence of pressure, during assembly or even simply if the pressure decreases. This deformation, which is translated by an ovalization of the conduit, is particularly troublesome when assembling the different panels which, to avoid these deformations, must, in general, be mounted on a gauge of the desired section, before welding.

The risk of deformation is even greater in very important sections, for example of several square meters. It is possible to use reinforced concrete tubular elements that have the advantage of not deforming when placed on the floor and covered, but for more important sections, this type of elements are heavy and bulky. On the other hand, a duct of circular section, which rests only on its lower part, exerts on the ground an important localized effort that can cause, due to the punching effect, differential crushes and, therefore, disorders. In addition, it is difficult to realize, between the adjacent elements, joints that are sufficiently watertight to withstand very strong pressures.

To solve such problems, the inventor already proposed, in the patent FR-A-2,685,304, to conduct mixed conduits constituted by a metallic tubular enclosure having, in straight section, a circular shape in a part of the section and presenting a face The bottom is substantially flat and is applied and fixed on a reinforced or prestressed concrete slab. In this way, this duct combines the advantages of the metal construction and the concrete construction since the circular metal part is subjected only to the tensile stresses and can therefore be constituted of a relatively thin wall, while the lower part is placed on the slab that can be provided in such a way that it resists the bending stresses thus generated and that, on the other hand, distributes the load over a large area, which reduces the stress exerted on the ground and the risks of crushing.

FR-A-2,685,304 discloses several particularly advantageous embodiments.

A conduit of this type perfectly resists the internal stresses * -exercised, in service, by the transported fluid, even under a very strong pressure. However, it can also be subjected to external stresses exerted, for example, by the filling under which the duct has been buried or simply by the atmospheric pressure, when the internal pressure decreases or is suppressed. To better resist external efforts, document FR-A-2.685.304 proposes to provide the conduit with a semicircular section. However, the diameter of such a duct is obviously double, at equal flow rate, of the diameter of a circular section duct. The light of the duct and, therefore, the width of the ditch in which it is placed, are increased. As indicated in the patent FR-A-2.685.304, in certain cases it is possible to get as close as possible to the circular section covering a sector greater than 180 °, being able to reach, for example, up to three quadrants, which decreases the width of the concrete slab. However, by increasing the area covered by the circular part, the risk of deformation of this and, particularly, of the side panels at the time of assembly is increased, which makes it difficult to align the panels for welding, and that the use of a gauge is, in practice, necessary. On the other hand, this duct must be made on a terrace-finished foundation whose leveling is not very precise. The operations of handling and setting of the different elements carried out in the work should be simplified as much as possible. Furthermore, even when the conduit is in service, a mere reduction of the internal pressure or even a mere effect of cavitation can lead to a collapse of the metal part under the weight of the filling. The invention provides a solution to these problems thanks to a "new embodiment that remedies the aforementioned drawbacks while preserving the advantages of the known technique." The invention thus relates to the realization of a fluid transport conduit subjected to a internal pressure, generally composed of a tubular fluid circulation enclosure bounded by a thin wall and fixed to a rigid support slab of molded material; said enclosure is composed of several juxtaposed panels, assembled along their adjacent sides and comprising, in straight section, a lower part applied and fixed to the rigid slab and a curved upper part in the form of a vault, which joins the lower part along both sides of fixing to the slab, the latter comprising an upper face for fastening to the tubular enclosure, a lower supporting face on the floor and two side faces. According to the invention, the upper part of the enclosure is constituted, in straight section, by at least three thin-walled segments, two lateral segments each extending respectively between a lower side and a Top side and at least one upper segment of closure of the enclosure that joins the upper sides of the side segments and each side wall segment thin is associated with a rigid support element in molded material fixed at its base to the corresponding side of the slab and extending upwards; each support element comprises an internal face of application of the lateral segment, with a profile conjugated to the latter and extending from the level of the upper face of the slab to a level sufficient to maintain the rigidity of said lateral segment throughout its height • no risk of sinking, even under the weight of the upper segment and in the absence of internal pressure. A particularly advantageous feature is that the thickness of the thin wall is determined according to the nature of the thin wall to withstand both the tensile stresses generated by the application of the internal pressure and the external filling atmospheric overpressure The level of the upper sides of the lateral segments is determined so that the upper segment, which extends between said upper sides, can be constituted in a single panel rigid enough so that it does not run the risk of sinking under its own weight when placed on the "" * lateral segments. In a preferred embodiment, each support element is limited, below the level of the upper face of the slab, and on the side thereof, by an internal side face of which at least a part is applied against at least one part. a corresponding part of the side face facing the slab, said side faces having conjugate profiles. Both support elements have the advantage of being placed on the floor, on either side of the slab, each of them by means of a base with a flat bottom face, of sufficient width to allow that element to remain straight before joining it with the slab. According to another advantageous arrangement of the invention, both support elements, placed on either side of the slab, are joined to it either by anchor pins or by prestressing cables which pass in the foreseen aligned covers, during the molding operation, inside the support elements and the slab following a profile substantially parallel to that of the corresponding parts of the enclosure; said prestressing cables are supported, after the tensioning, on the support faces provided, during the molding operation, on the support element, at the exit of said covers.

To make a tight assembly between the metal panels, the lateral edges facing each side segment and the lower thin-walled segment are separated, at a certain distance, from the joint plane, leaving both parts of it, a notch in which it is placed. Place a welded joint, after installation, on the side segment and on the lower segment so that the continuity of the enclosure wall is restored. According to another advantageous feature, the upper thin-walled segment that closes the enclosure upwards has a width greater than the distance between the upper extremities of the lateral segments, so that it covers them at a certain distance; two weld beads are made, after installation, on both internal and external faces, respectively, of the thin wall, along the ends of each lateral segment and the upper segment respectively. Other advantageous features are the object of the sub-claims. But the invention will be better understood with the following description of some particular embodiments, which are given as an example and are presented in the accompanying drawings. Figure 1 is an overall view, in perspective, of a section of conduit according to the invention. Figure 2 is a cross section of a duct of this type, in a preferred embodiment. Figure 3 is a detail, in perspective, of a transverse junction joint. Figure 4 and Figure 5 are details, in cross section, showing other embodiments of the joint between a support element and the slab. Figure 6 is a cross section of another embodiment of the conduit. FIG. 1 shows a section of a duct according to the invention, generally comprising a metal tubular enclosure 1 fixed on a rigid reinforced concrete slab 2, comprising a flat bottom face 21, two lateral faces 22, 22 ', and an upper face 23. The enclosure is placed on a flattened and crushed surface which may be, for example, the bottom B of a trench C; after construction, the enclosure is filled with filler. The tubular enclosure 1 is limited by a thin metal wall, completely closed in a straight section, comprising a lower part 11 applied to the upper face 23 of the slab 2, and a cylindrically shaped upper part 12 centered on a longitudinal axis 10. The lower part 11, which extends between the two lateral edges 24, 24 'of the slab 2, is flat or slightly curved. The upper part 12 covers, in a straight section, a circular sector and extends, between both lateral edges 24, 24 ', by an angle A greater than 180 °. The metallic tubular enclosure 1 is constituted by juxtaposed panels, welded along their adjacent sides and normally covering, in straight section, four segments of the wall, which are respectively a lower segment 11, which extends along the slab 2 between the two lateral edges 24, 24"of the same, and three segments 13, 13 ', 14, which constitute the upper part 12 of the enclosure, two side segments 3, 3' and an upper segment 4 respectively. Each lateral segment 3, 3 'stands vertically between a lower edge 31 extending along the corresponding lateral edge 24 of the lower part 11 and an upper edge 32, located at a height H1 above said lateral edge 24.

The upper element 4 covers an arc whose rope is a little greater than the distance between the upper edges 32, 32 'of the lateral segments 3, 3', so that the ends 41, 41 * of the upper segment 4 cover, in a certain length, the ends 32, 32 'of the side segments 3, 3'. i AND! The upper segment 4 thus forms a metallic parabola resting on the two lateral segments 3, 3 ', and which can be suspended to a maintenance bar, either by means of clamps which are hooked on the lateral edges 41, 41' or by means of hooks that are attached to the anchor points provided for that purpose in the parabola.

However, the level H1 of the upper extremities 32 of the lateral segments 3 has been determined in such a way that the distance D between the lateral extremities 41, 41 'of the parabola 4 is sufficiently small to avoid an excessive deformation thereof. by its own weight, taking into account the nature of the metal that constitutes the metal wall, its thickness and its rigidity.

According to the essential characteristic of the invention, each lateral segment 3, 3 'is placed on a support element 5, 5', constituted by an elongated piece of reinforced and / or prestressed concrete, capable of being placed next to the slab 2 and which comprises a curved face 51 of profile conjugated to that of the lateral segment 3 which can thus be placed and fixed on the support element 5 along the entire face 51. The latter extends over most of the length of the segment lateral 3 from its lower extremity 31. In this way, only a part of scarce .. - length 33 of the lateral segment 3 extends upward from the level of the upper extremity 52 of the support element 5 and up to the extremity 32 of the element 3. The height H2 of the bearing face 51 is determined so as to maintain the rigidity of the lateral segment 3 over its entire height, the length of the extremity remaining in air 33 being sufficiently reduced for the same no is distorted, even by the weight of the upper parabola 4. Furthermore, in case of need, the support legs 34, in the form of curved elbows, could be bolted to the upper face 52 of the support element 5 to maintain the rigidity of the extremity 33 of the lateral segment 3. In this type of embodiment, the slab 2 is constituted, like the supporting elements 5, 5 ', by prefabricated elements placed edge to edge. The thin-walled segments 3, 11 can be associated, during the molding, with the concrete parts 5, 2 which have the advantage of flat concreting. Each metallic face 3, 11 then constitutes the bottom of the mold and carries protruding anchoring parts 17, which are embedded in the concrete during concreting. After emptying, the concrete element provided with the corresponding metal face is turned over so that it forms the slab 2 or stands up to constitute a support element 5, 5 '. This type of duct can be constructed in advance, by successive sections, in the following way: - the thin-walled curved elements are cut and shaped, respectively covering at least four segments of the periphery of the tubular enclosure 1: two lateral segments 3 , a lower segment 11 and an upper segment 4 respectively, I - Two types of prefabricated reinforced concrete elements, each provided on one side with a thin-walled segment constituting a lost formwork sealed in the concrete, are prepared in advance in the desired quantity. of reinforced concrete covered with a lower segment 11 and support elements 5 having a curved face covered with a lateral segment 3 respectively, - with these prefabricated elements, which will have been contributed in the desired amount to the work, to build a new section from conduit to • - continuation of a part already made, a slab element 2 and two support elements 5, 5 'are placed on the installation surface B, aligning them with the corresponding elements of the part made and applying one on the other the side faces facing to the support elements and to the slab 2, - the welds are made, on the one hand, between the segments 11, 3, 3 'of the section that has just been installed, along the lower sides 31, 31 'and above 32, 32' and, on the other hand, in the transverse plane P of connection, between each segment 3, 11 of the new section and the corresponding segments 3a, 11a of the part already made, along its adjacent sides, - the upper wall segment 4 is placed on the upper ends 32, 32 'of the side segments 3, 3' and said upper segment 4 is longitudinally welded with the side segments 3, 3 'and transversely with the segment It is preferable that each support element 5 rests directly on the ground by a flat face 53 and that it is provided, below the application face 51 of the segment 3, with a supporting face 52 that comes to be placed against the corresponding lateral face 22 of the slab 2.

The application of the support elements 5 against the slab 2 can be carried out, for example, by means of several pins 6 passing through the holes 60 provided in the lower part of the support elements 5 'and whose ends 61 are screwed in the threaded bores 62, constituted by inserts that are sealed during the molding on the sides of the slab 2. But also bars can be used that go through the assembly formed by the slab 2 and both support elements 5. In the mode of simpler embodiment, represented in Figure 1, both side faces 22, 22 'of the slab 2 are flat as well as the bearing faces 52, 52' of the support elements 5, 5 '. Figure 2 shows a more advanced embodiment in which the side faces 22, 22 'of the slab 2 and the conjugated faces 52, 52' of the support elements 5, have a stepped profile comprising, in its central part , inclined or horizontal faces, 25, 55 respectively, creating a socket that avoids the relative movement of the support elements with respect to the slab. It will be noted that the stepped faces 22, 52 can advantageously be consolidated with metal walls that serve as lost formwork, so as to ensure a perfect application of the two faces conjugated one on top of the other and, in addition, the risks of deterioration during the operations are avoided. of maintenance of the prefabricated elements. Thanks to these arrangements, the support elements 5, 5 'are perfectly fitted on the sides of the slab 2 and are not at risk of moving relative to it, which favors the bonding by welding between the lateral segments 3, 3'. and the lower segment 11 of the thin wall.

To improve this connection, it is advantageous to stop the lower edge 31 of each lateral segment 3, 3 'and the leading edge 11' of the lower segment 11, at a certain distance on both sides of the joint plane Q between the slab and the element of support, so as to leave two aligned notches 36, 16 of thickness substantially equal to that of the thin wall, in which a cover 7 is placed constituted by a metal strip of the same thickness and bent so as to have two wings 71, 72 that tangentially join with the lower extremity of the lateral segment 3 - - and with the corresponding end of the lower segment 11 of the thin wall respectively.

As indicated in Figure 2, both sides 36, 37 of the notch can be formed by recessed portions provided along the ends facing the segments of the thin wall 3, 11.

In this way, each cover 7 ensures the continuity of the metal wall without further protrusion towards the interior than the weld beads 73, 73 'which are made between the side edges of the cover 7 and the internal edges of the recessed portions 36, 16 of the lateral segment 3 and of the lower segment 11 respectively.

Along the transverse joints 35 between the adjacent elements, the metal segments can be welded edge to edge. In particular, as shown in Figure 1, the concrete support element 5 must not necessarily cover the entire length of the corresponding metal wall 30 and then it may protrude at the ends to facilitate welding.

But it is also possible, as shown in FIG. 3, to provide recessed portions 37, 37a at the ends facing the front of the adjacent segments 3, 3a, 11, 11a to limit a notch in which a cover band 77 is placed. This can be arranged on the outside to facilitate assembly, or on the inside, such as the longitudinal strips 71, if the projections inside the conduit are to be avoided. In order to avoid cross welding, it is possible to displace the transverse joint planes, on the one hand between the lateral segments 3, 3a and, on the other hand, between the upper segments 4, 4a and the lower segments 11, 11a. It should be noted that the application of the lateral faces 22, 52, of the slab and of the supporting elements on one another can be done on one side only 22a, 52a thereof, in which the holes for the passage of the pins have been provided. 6, with interposition of a compressible gasket 64 surrounding the pin. Each pin 6 is preferably perpendicular to the application faces 22a, 52a, as indicated in Figure 2. However, it may be advantageous in certain cases to tilt the pin 6 with respect to the application faces 22a, 52a, as indicated in Figure 4. To lighten the slab 2 and improve its resistance to the bending stresses generated by the application of the internal pressure, it is advantageous to subject it to a transversal pretension. In this case, the pins 6 serve essentially to the provisional maintenance of the support elements 5 that are definitely joined to the slab 2 by pre-tension cables 8 surrounding the lower part of the conduit passing in the built-in covers 80, during molding, in the elements of slab 2 and the support elements 5, and which are tangentially joined in the joint planes. Each prestressing cable 8 is provided with an anchor head 81 that takes support on a corresponding face 57 provided on the outer side of the support element 5 perpendicular to the direction of the cable, at the exit thereof. Likewise, slabs 2 can be provided with sheaths 83 parallel to the axis 10 of the conduit and, possibly, in the support elements 5 to allow the passage of cables 82 which, after the power-up, ensure the joining of the adjacent sections. with a longitudinal pretension of the assembly that allows, in particular, better resist the differential crushing. In the upper part, as already indicated, each parabola element 4 simply has a width greater than the distance between the upper extremities 32, 32 ', of the lateral segments 3, 3' so as to cover them, and they are made in the interior weld seams 74, 75, along the edges 32, 32 'of the side segments 3, 3' and on the outside, along the edges 4, 4 'of the parabola 4. For improving the stability of the support elements 5, it may be advantageous to provide them, at their base, with shoe-shaped parts extending outwards to widen the lower face 53 of each element 5. On the other hand, such shims improve the stability of the support element 5 opposing the overturning towards the outside thereof before the filling is added. Of course, the invention is not limited to the details of both embodiments that have just been described as a simple example; other variants may be projected without departing from the protection framework defined in the claims. For example, in another embodiment using the technique called "confined concrete", each element of the slab 2 is limited, on all sides, by a closed metal wall that covers not only the upper face 11 but also the face lower 21 and the side faces 22, so that a hollow caisson is formed that is filled with concrete with a slight overpressure that allows to compensate the shrinkage. It is then possible to suppress armor that is replaced by the walls of the drawer.

But the slab 2 can also be concreted on the site in advance, between two formworks or between the internal faces 52, 52 'of the maintenance elements 5, 5'. In this case, the lower part 11 of the metal wall can be formed by cut segments that are applied to the concrete before it sets. The previously prepared concrete slab can also have notches filled with mortar and into which the anchoring parts welded in the lower part of each wall segment 11 are inserted, a grout can be injected between the metal segment and the upper face 23 of the slab to ensure the solidarity and the transmission of pressure efforts.

In this case, for example, after having carried out the duct in a certain length and having prepared a flat installation surface in its extension, the maintenance elements 5, 5 ', provided with the lateral segments 3, 3', are placed first. respectively, aligning them with the already installed part and welding the adjacent lateral segments along their transverse edges 35. The iron reinforcement of the slab 2 is then placed and, if applicable, the pre-tensioning sheaths that are aligned with the covers corresponding to the side elements 5, 5 '. The concrete slab is then concreted to which the lower segment 11 is sealed. The prestressing cables that are put into tension are then passed and with the different elements correctly applied, the segment 11 is welded along the its transverse edge 15 with the segment 11a of the part already installed and along its lateral edges with the edges 31 of the lateral segments 3, 3 '.

Then parabola 4 can be placed by welding it with parabola 4a already installed and with the lateral segments 3, 3 '. On the other hand, the stepped profile of the lateral faces 22, 52 of the slab 2 and of the supporting elements 5, 5 'can also be inverted in the manner indicated in Figure 4, the slab 2 is then provided with lower flanges 26. passing under the upper flanges 56 of the support element 5. This type of arrangement allows, when a new section is constructed, first place one or more slab elements in the extension of the part already installed, joining them, if necessary, to the same with prestressing bars and that the support elements 5, 5 'are then placed in the desired amount,? both sides of the slab that constitutes the alignment reference. As indicated in Figure 5, the side edges facing each support element 5, 5 'and the slab 2 can be covered with the protection elbows 57, 27, forming lost formwork and on which the ends 31, 11 are welded. 'of the wall segments 3, 11, which stop at a certain distance from the joint plane Q to provide the two sides 36, 16 of the notch in which the cover plate 7 is placed. On the other hand, it may be advantageous, particularly To reduce the width of the trench C, mount the pins 6 from the interior of the duct, as indicated in Figures 5 and 6. In this case, to make a new section of the duct, first place the two support elements 5, 5 ', aligning them with the corresponding elements of the part already made. The elements 5, 5 'are provided with lower flanges 54 in which internally threaded inserts 62 have been sealed. After the joints 64 have been placed in the outlet of each insert 62, the slab elements 2 are placed which fit between the support elements 5, 5 'and which are provided with holes 60 that come in the alignment of the inserts 62 The pins 6 are then placed whose head 63, which can be constituted by a nut, is housed in a notch 27 provided in the upper face of the slab 2. After having blocked the pins 6, the cover 7 is placed and weld in the elbows 28, 58. It will be noted that, in the case where the risks of landslides are significant, the upper segments 4 can be placed in the side elements 3, 3 'from the assembly of the slab elements 2 so as to protect the workers during the operations of placing the pins and welding the joints. According to another advantageous feature, shown in Figure 6, the passage holes 60 of the pins 6 completely pass through the slab 2 and the support elements 5. After having placed the prefabricated elements, perforations in the floor can be made in the floor. which are sealed the straps 6 'of great length. Such an arrangement can be used, for example, in the case where the duct is immersed in the water table and there is a risk that the ballast effect provided by the support elements 5, 5 'and the slab 2 sufficiently understand the push of Archimedes. As also shown in Figure 6, it is also possible to give the slab 2 a thickness less than that of the side faces 52 of the support elements 5, 5 ', so that the slab 2 does not rest on the floor but only on the floors. support elements 5, 5 ', by upper flanges 26a. The profile of the slab 2, in cross section, must then simply be provided to allow, having the iron reinforcement counting, to resist the bending stresses applied by the lower segment 11 subjected to the pressure that reigns inside the enclosure . The reference signs inserted after the technical characteristics mentioned in the claims have for - "only objective to facilitate the understanding of them and do not limit in any way the scope.

Claims (22)

1. Fluid circulation conduit under internal pressure which comprises, in general, a tubular enclosure (1) bounded by a thin wall (1) and fixed to a rigid support slab (2) in molded material, said enclosure (1) being constituted by several juxtaposed panels, assembled along their adjacent sides and comprising, in straight section, a lower part (11) applied and fixed to the rigid slab (2) and a curved top part (12) in the shape of a dome that is it connects the lower part (11) along both lateral sides (31, 31 ') of fixing on the slab, the latter comprising an upper face (23), a lower face (21) and two side faces (22, 22"), characterized in that the upper part (12) of the enclosure (1) is constituted, in a straight section, by at least three thin-walled segments, two lateral segments (3, 3 ') each extending respectively between a lower side (31). ) and an upper side (32) and at least one upper closure segment (4) of the enclosure (1) that joins the upper sides I (32, 32 ') of the side segments (3, 3') and because each thin wall side segment (3, 3 ') is associated with a rigid support element (5 5') in molded material fixed at its base to the corresponding side of the slab (2) and extending upwards, each support element (5, 5 ') comprises an inner face (51, 51') turned towards the enclosure (1) having a profile conjugated to that of the lateral segment and on which the latter is applied, said internal face (51, 51 ') extends from the level of the upper face (23) of the slab (2) to a level (H2) sufficient to maintain the stiffness of said segment l ateral throughout its height (H1) without risk of subsidence, even under the weight of the upper segment (4 > and without application of internal pressure.

2. Conduit under pressure according to claim 1, characterized in that the thickness of the thin wall (1) is determined according to the nature of the same, to simply resist the tensile stresses generated by the application of the internal pressure and that the level (H1) of the upper sides (32, 32 ') of the side segments (3, 3') is determined so that the upper segment (4) extending between said upper sides can be formed in a single panel rigid enough so that it does not run the risk of sinking with its own weight when placed on the lateral segments (3, 3 ').

Conduit under pressure according to one of claims 1 and 2, characterized in that both support elements (5, 5 ') are placed on the ground on both sides of the slab (2), each of them by means of a base with flat bottom face (53).

4. Conduit under pressure according to one of claims 1 to 3, characterized in that each support element (5, 5 ') is limited, below the level of the upper face (23) of the slab (2) and the side of the slab (2). the latter by an internal side face (52) of which at least one part (52a) is applied against at least a corresponding part of the side face facing front (22) of the slab (2), said side faces having (22) ) of the slab and (52) of the maintenance elements (5) conjugated profiles.

Conduit under pressure according to claim 4, characterized in that each support element (5, 5 ') is associated with means (6, 8) for joining the support elements (5, 5') to the slab (2) by applying one on the other at least of the corresponding parts (52a, 22a) of the conjugate side faces (52, 22).

Conduit under pressure according to claim 5, characterized in that the means for joining the two support elements (5, 5 ') to the slab (2) are constituted by several transverse prestressing cables (8) that pass in the covers aligned (81) provided, during the molding, inside the support elements (5, 5 ') and the slab (2) following a profile substantially parallel to that of the corresponding parts of the enclosure, said prestressing cables taking support (8), after the tensioning, on support faces (57 ') provided, during molding, in the support element, at the exit of said covers (81).

7. Conduit under pressure according to claim 5, characterized in that the means (6) for joining the support elements (5, 5 ') to the slab (2) are constituted by several pins (6) that extend transversely to the parts of conjugate application (52a, 22a) of said side faces and distributed along the length of each element (5), each pin (6) taking support by one end (63) on the support element (5) and the other end ( 61) on the slab (2) or vice versa.

8. Conduit under pressure according to claim 7, characterized in that each fastening pin (6) passes in aligned holes provided in the support element (5) and the slab (2), and comprises an internal end (61) sealed in the slab ( 2) and a support head (63) on the support element (5), or vice versa.

9. Conduit under pressure according to claim 8, characterized in that the fastening pins (6) are placed from the outside and take each support, by its head (63), on the external side face (50) of the support element (5). ).

10. Conduit under pressure according to one of claims 4 to 9, characterized in that the conjugated lateral faces (52) (22) of each support element (5, 5 ') and of the slab (2) have a stepped profile that leaves, along said conjugate side faces (52) (22) protruding and recessed portions, respectively, which fit together.

Conduit under pressure according to claim 10, characterized in that the conjugated lateral faces (52) of the support elements (5) and (22) of the slab (2) comprise, in their central part, an application part (52a) ) (22a) that forms an angle less than 45 ° with the horizontal.

The pipeline under pressure according to one of claims 10 and 11, characterized in that the internal side face (52) of each support element (5) comprises, at its base, a lower flange on the projection (54) that is hooked by under a corresponding flange (25) provided in the upper part of the corresponding lateral face (22) of the slab (2).

13. Conduit under pressure according to claim 12, characterized in that the slab (2) has a thickness less than the distance between the lower part (11) of the wall (1) and the floor (B) and takes support, by its flanges higher (25) in the two support elements (5, 5 ') that frame it.

14. Conduit under pressure according to one of claims 10 to 13, characterized in that the fastening pins (6) are placed from the interior of the enclosure (1) and pass through the application parts (52a, 22a), each pin (6). ) takes support, by its head (63) on the upper face (23) of the slab (2).

15. Conduit under pressure according to claim 14, characterized in that the fastening pins (6) are extended so that they extend into perforations provided in the underlying ground and are sealed thereto.

16. Conduit under pressure according to one of the preceding claims, characterized in that the lower edge (35) of each side wall segment (3) and the corresponding side edges (11 ') of the lower segment (11) applied to the slab ( 2), are separated at a certain distance from the joint plane (Q) between the support element (5) and the slab (2), leaving on both sides of said plane (Q) a notch covered by a cover (7) which is welded, after installation, with the lateral segment (3) and the lower segment (11), so as to restore the continuity of the internal face of the enclosure.

17. Conduit under pressure according to claim 16, characterized in that the front ends (35) to each side segment (3) and (11 ') of the lower segment (11) are provided with recessed portions (36, 16) that limit the notch in which the cover (7) is placed.

18. Conduit under pressure according to one of the preceding claims, characterized in that the thin-walled upper segment (4) closing the enclosure upwards has a width greater than the distance between the upper extremities (32, 32 ') of the lateral segments ( 3, 3 '), so that these are re-located at a certain distance with two weld seams (74, 75) which are made, after installation, on both internal and external sides of the thin wall respectively, along the extremities of each lateral segment (3) and the upper segment (4) respectively.

19. Method of construction of a fluid transport conduit, placed on a flattened and crushed surface (B), and constituted by a tubular enclosure limited by a thin wall and fixed to a rigid support slab in molded material, characterized in that: - thin-walled curved elements are cut and shaped, respectively covering at least four segments of the periphery of the tubular enclosure (1), two lateral segments (3), a lower segment (11) and an upper segment (4) respectively, - Two types of prefabricated reinforced concrete elements each provided on one side of a thin wall segment constituting a lost formwork sealed in the concrete, of slab elements (2) are made in advance and in the desired number. of reinforced concrete covered with a lower segment (11) and supporting elements (5) with a curved face covered with a lateral segment (3) respectively, - with these prefabricated elements, which will have been provided, in the desired number to the To build a new section of duct after a part already made, a slab element (2) and two support elements (5, 5 ') are placed on the installation surface (B), aligning them with the corresponding elements of the part made and applying one on the other side faces facing the support elements (5) and the slab (2), ' - the welds are made, on the one hand, between the segments (11, 3, 3 ') of the section that has just been installed, along the lower (31, 31') and upper (32, 32 ') sides and , on the other hand, in the transverse plane (P) of connection, between each segment (3, 11) of the new section and the corresponding segments (3a, 11a) of the part already made, along its adjacent sides, - the upper wall segment (4) is placed on the upper ends (32, 32 ') of the side segments (3, 3') and said upper segment (4) is longitudinally welded with the side segments (3, 3) ' and transversally with the upper segment of the part already made,

20. Method according to claim 19, characterized in that the two support elements (5, 5 ') are first placed on the installation surface on both sides of the longitudinal axis of the duct and they are aligned with the corresponding elements of the part already installed, then the slab element is placed (2) between said support elements (5, 5 ').

21. Method of construction of a fluid transport conduit, placed on a surface (B) flattened and crushed and constituted by a tubular enclosure limited by a thin wall and fixed on a rigid support slab in molded material, characterized in that: - the thin-walled curved elements are cut and shaped, respectively covering at least four segments of the periphery of the tubular enclosure (1), two lateral segments (3), a lower segment (11) and an upper segment (4) respectively , - prefabricated reinforced concrete support elements (5, 5 ') each having a curved face on it is applied in advance and, in the desired quantity, a thin-walled side segment (3) is sealed. it constitutes a lost formwork, - with these prefabricated elements, that will have been contributed in the desired quantity to the work, to build a new section of conduit after a part already made, they are placed on the s installation surface (B) two supporting elements (5, 5 '), aligning them with the corresponding elements of the part made, - with the support elements (5, 5') thus installed and aligned at a certain distance, a concrete corresponding slab length (2) between the side faces (52, 52 ') of the support elements (5,5') and a desired number of thin-walled lower segments (11) is sealed on said slab (2); - the welds are made, on the one hand, between the segments • (11, 3, 3 ') of the section that has just been installed, along the lower (31, 31 *) and upper (32, 32') sides and, on the other hand, in the transverse plane (P) of connection, between each segment (3, 11) of the new section and the corresponding segments (3a, 11a) of the part already made, along 5 its adjacent sides, I - the upper wall segment (4) is placed on the upper extremities (32, 32 ') of the lateral segments (3, 3') and "" welds said upper segment (4) longitudinally with the lateral segments (3, 3 ') and transversely with the upper segment of the part already made 0.

22. Method according to one of claims 19 to 21, characterized in that, in case of risks of landslides, the upper segment (4) is first placed on the ends (31, 31 ') of the lateral segments (3, 3') and then the whole of the welds is made in the interior of the enclosure (1) thus closed.