EP0065486B1 - A constant cross-sectional elongated piece of work and a method of constructing this piece of work - Google Patents

Abstract

The reinforced concrete structure of this construction comprises tubular elements of permanent shuttering, connected by structural parts defined by external pile planks and internal permanent shuttering tangential to the tubular elements. The method of building consists in driving in the tubular elements and the pile planks over the entire length of the construction, emptying the tubular elements of the earth with which they are filled, reinforcing and casting concrete into these elements, excavating the interior of the section defined by these tubular elements and the pile planks, progressively disposing props, inserting the inner shuttering between these props and these tubular elements and subsequently reinforcing and casting concrete between this shuttering and the pile planks.

Description

The present invention relates to an elongated underground structure of constant section having a reinforced concrete structure surrounding at least the part of the cross section of this structure forming a free volume above its bottom, and to a process for manufacturing this structure. work.

The construction of underground structures in particular, of passages under working traffic routes, roads or railways, poses problems because traffic must be able to continue during the works. This construction requires multiple precautions and in particular imposes a slowdown in traffic, especially that of rail traffic.

It has already been proposed, in patent CH-442,404, to form a hollow structure of reinforced concrete having a parallelepiped shape open axially and whose cross section corresponds to that of the underpass. The front edge of this structure is shaped with a sharp edge so that it can be driven into the ground over a certain length using jacks. Then the portion of the soil included inside this hollow structure is excavated. Once the excavation has reached the front end of the reinforced concrete structure, it is once again driven in for a certain length and then excavated, so on until a complete passage is made.

If this solution is supposed to solve the problems inherent in the drilling of an underground passage under a traffic lane in service by avoiding the slowing down of traffic during the works, its implementation requires considerable means, in particular an installation of high power jacks as well as works capable of serving as support for these jacks. The continuous advance of the reinforced concrete structure also poses problems with the length of jacks, the hollow structure advancing while the supporting structures remain fixed. In addition, the necessary pressure is considerable taking into account the friction surface which increases as the structure is pushed in. Consequently, this solution poses fairly complex implementation problems which make it costly to produce due to the additional work caused by the structures serving to support the jacks. If it is undeniable that such a solution makes it possible to solve the problem of piercing a passage under a traffic lane in service without significant slowdown in traffic, it is therefore at the cost of significant practical difficulties and an increase construction costs.

It has already been proposed in US Pat. No. 4,009,579 to drive tubes side by side arranged substantially horizontally in the ground and intended to extend longitudinally to the place where will be delimited what will later become the upper part of an underground structure. Then, we proceed to the excavation below the area covered with tubes and we have, as the work progresses, props in the form of frames made using reinforced concrete beams and oriented according to the successive cross sections of this work. The succession of these frames, adjacent to each other, thus forms a continuous wall. These frames are linked together by mortar injected into the space separating these frames, on the one hand from the tubes and, on the other hand, from the surface excavated in the ground.

The essentially prefabricated construction of this structure is relatively slow. The installation of adjacent frames is complicated by the fact that the excavation of the ground is not precisely delimited which requires the setting of each frame. The filling of the free spaces appearing between the excavated volume and the frames with mortar results in an expenditure of additional cement while the connection of the frames with mortar gives a relatively low resistance to the structure so that the end frames of the passage must be retained axially by a support structure.

This is therefore a satisfactory solution neither technically nor economically. DE-A-1 759 309 also relates to the construction of an underground structure produced using tubes placed side by side in the part intended to form the ceiling of the structure and linked together by elements of tension anchored to these tubes. The establishment of these tubes is carried out by sinking into the ground after which a volume is excavated below these tubes. As the excavation progresses, these tubes are supported by props in the form of frames arranged along the cross section of the structure. These tubes are filled with prestressed concrete and the spaces left free between them are filled with shotcrete. The interior of the structure is then lined with traditional masonry. This document does not specify what the supporting structure of this structure consists of or the nature of the interior masonry, simple coating or reinforced wall. However, it does not seem possible that this load-bearing structure consists only of tubes filled with prestressed concrete due to the lack of cohesion of such a structure, each beam being independent of the adjacent beam and the absence of lateral load-bearing walls. . The masonry work necessary for finishing and the nature of which is not specified, should be significant. Finally, the installation of tension elements anchored to these tubes to link them requires tubes of sufficient diameter to allow a man to enter to do this work. However, since these tubes are then filled with concrete, the volume of concrete required is considerable. These huge concrete cylinders rest, moreover, on the masonry structure which should be load-bearing and therefore require significant formwork and reinforcement work. This is a technically and economically unsuitable solution to the problem of building an underground structure.

It was proposed in patent BE-872 754 to sink tubes into the ground to form a vault resting on walls at its two lateral ends, prestressed concrete beams being formed transversely to support these tubes filled with concrete, after which the work is excavated. This technique assumes tubes of sufficient diameter to allow a man to circulate there, all the masonry work, including the walls supporting the vault, being completed at the time of excavation.

These solutions often only provide a relative simplification of the construction of an underground structure, require formwork and formwork operations or assume large diameter tubes ill-suited to the construction of underpasses, for example. The limits of the volume to be excavated are not defined except in the aforementioned Belgian patent, however, in this case, it is necessary to form the concrete walls carrying the vault before excavating which, in addition to the tubes of large diameters, requires the drilling of galleries posing problems of evacuation towards the outside of the materials resulting from the excavation of the galleries and volumes delimiting these load-bearing walls. Obviously, such a technique is not suitable for the construction of works such as underpasses.

The object of the present invention is to remedy these drawbacks at least in part and at the same time offer a technically advantageous solution by itself, both for making underground passages under traffic lanes in service and for drilling and construction of any other elongated underground work of constant section.

To this end, the present invention firstly relates to an elongated underground structure of constant section as known from US-A-4009579 and having a reinforced concrete structure surrounding at least the part of the cross section of this structure forming a free volume above its bottom, this structure comprising cylindrical concrete beams injected into tubes extending parallel to each other in the longitudinal direction of this structure, as well as stays in the form of frames arranged transversely to the interior of this structure, characterized in that these tubes are spaced from one another and are interconnected by lost formwork elements, each of which is engaged with two adjacent tubes to delimit the external face of a wall of reinforced concrete , delimited internally by other lost formwork elements disposed between these tubes and said struts spaced longitudinally from each other.

This invention also relates to a method of constructing this underground structure. characterized by the fact that successively, by turning around the straight section of the structure, said tubular elements and said lost formwork elements connecting these tubular elements, of a certain length, are repeated and repeated if necessary this cycle until the total length corresponds to that of the structure, said tubular elements are filled with reinforced concrete, the space delimited by these tubular elements is excavated and the lost formwork elements connecting them, the said props are placed as the said structure is excavated, the lost formwork elements are inserted between these struts and these tubular elements and the spaces delimited by the lost formwork elements connecting the tubular elements and those tangent to them are filled with reinforced concrete .

• La figure 1 illustre une coupe longitudinale d'une forme d'exécution d'un passage souterrain.
• La figure 2 est une vue selon II-II de la fig. 1.
• La figure 3 est une vue de détail en élévation latérale illustrant une phase du procédé.
• Les figures 4 et 5 illustrent deux variantes d'un détail constructif.
• La figure 6 est une vue en élévation d'un autre détail.
• La figure 7 illustre une variante de la fig. 2.

The advantages arising from this invention are numerous. Among these, it should be noted that forming an envelope around the cross section of the passage and over its entire length, before excavating it, this envelope being reinforced with concrete beams over the entire length of this structure. The envelope thus formed is used first of all to delimit the volume to be excavated, then of lost formwork to produce the supporting structure integrating the reinforcement beams of the envelope. The props installed during the excavation to support the longitudinal beams are also used for fixing the lost formwork elements delimiting the internal face of the supporting structure, so that this structure is obtained, after reinforcement, simply by injection of concrete in the formwork previously used to delimit the excavated volume. This technique therefore makes it possible to combine great simplicity with a technically safe solution. Other advantages will become apparent on reading the description of an embodiment and of a variant of the invention which follows, illustrated diagrammatically by the appended drawing.

• Figure 1 illustrates a longitudinal section of an embodiment of an underground passage.
• Figure 2 is a view along II-II of FIG. 1.
• Figure 3 is a detail view in side elevation illustrating a phase of the process.
• Figures 4 and 5 illustrate two variants of a constructive detail.
• Figure 6 is an elevational view of another detail.
• FIG. 7 illustrates a variant of FIG. 2.

The structure, illustrated in figs 1 and 2, consists of an underground passage which includes a reinforced concrete structure 2 surrounding the cross section of this passage 1. This reinforced concrete structure is formed on the one hand inside 'tubular elements 3 serving as lost formwork, extending longitudinally at passage 1 and distributed around its cross section, as illustrated in fig. 2. On the other hand, this structure is delimited internally by a lost formwork 4 tangent to the tubular elements and formed by metal profiles protected against corrosion and externally, by sheet piles 5 whose longitudinal edges have profiles 5a engaged in slides longitudinal 6 fixed in substantially diametrically opposite positions against the external face of each tubular element 3. Shores assembled so as to form frames arranged substantially at equal distance from each other inside the reinforced concrete structure 2, extend in respective planes corresponding to the cross section of the passage 1. The side walls and the ceiling of this passage are formed by profiled sheets 8 fixed inside the stays 7 in the form of frames. The bottom of the passage receives a raft covered with a covering 9.

The method of construction of this passage consists in first of all pushing in the tubular elements 3 and the sheet piles 5 one after the other over a certain length. The tubular elements 3 and the sheet piles 5 can moreover be dimensioned with the length corresponding to that of the desired insertion, for example 10 to 12 meters. The slides 6 and the edges 5a of the sheet piles 5 are mutually engaged to guide them as they are driven into the ground. This depression is achieved using a pneumatic horizontal threshing apparatus 10 illustrated schematically in FIG. 3. This device comprises a cylinder containing a free piston of 20 to 160 kg driven in an alternating movement at a frequency between 320 and 460 Hz depending on the model, supplied with pressurized air supplied by a compressor 12, at a pressure of 6 bar. The air consumption is between 1 and 6 m ³ / min and the force developed is between 7 and 85 kpm. The diameter of the cylinder enclosing the piston is from 70 to 155 mm depending on the model and its end ends in an adapter cone 11 to the tubular element 3 between 140 and 400 mm in diameter. This threshing device, of Soviet construction, exists in four models sold in Switzerland by the house R. Lehmann AG 8606 Werrikon b / Uster under the references IP 60. IP 4605, IP 4603 and IP 500. For the insertion of tubular elements 3, in this example steel tubes 200 mm in diameter, 12 meters in length and 4.5 mm in wall thickness, the apparatus 10 is positioned in the extension of the longitudinal axis of a tubular element 3 and the cone 11 is applied against the end of this tubular element 3, for example using tension cables 13 anchored in the ground and hooked around the base of the adaptation cone 11. We then supply the 'apparatus 10 in compressed air supplied by the compressor 12. As soon as the first beats, the adapter cone gets stuck in the opening of the tubular element 3, so that the tensioning cables 13 become unnecessary.

Different variants are possible. The front end of the tubular element 3 can be left open, in which case the earth fills the interior of this tubular element as it is pushed in. Depending on the nature of the soil and the length of the passage to be drilled, the front end of this tubular element 3 can be provided with a conical cover 14, (fig. 4) which avoids having to remove the soil from the interior of this tubular element 3 thereafter. Finally we have shown in fig. 5 another variant according to which the front end of the tubular element 3 is surrounded by a ring 15 intended to cut in the ground a hole of diameter slightly greater than that of the tubular element 3, which makes it possible to reduce the friction forces and is useful in particular for drilling relatively long passages.

Once a tubular element 3 has been partially depressed, a sheet pile 5 is arranged by engaging its profiled edge 5a in one of the slides welded along the tubular element. The adapter cone 11 is replaced at the front of the apparatus 10 by a slot template 16 (fig. 6) intended to receive the rear edge of the sheet pile 5 and the latter is pressed in the same manner as the tubular element 3. In this example, the distance between the tubular elements 3 is 65 cm.

Thus, successively, partially, each tubular element 3 and each sheet pile 5 are pressed in alternately until the entire straight section of the underground passage 1 is delimited by this structure.

In case the length of the passage exceeds that of the tubular elements 3 and of the sheet piles 5, a second tubular element and a second sheet pile end to end are added to each tubular element and to each sheet pile driven in during the previous threshing operation. In this case, these tubular elements and these sheet piles are welded in line with each other. Such an operation can be repeated several times, until the passage of desired length is obtained.

The following operation consists in emptying the tubular elements 3 in the event that these were not provided with a conical cover 14 such as that illustrated in FIG. 4. To this end, a pressurized water jet is advantageously used, which makes it possible to fluidize the earth and to entrain it outside the tubular conduit. You can also use compressed air or push the earth plug with a piston.

Once the tubular elements 3 have been emptied, reinforcement is introduced and concrete is injected under pressure. After taking this one begins the excavation of the earth included inside the space delimited by the tubular elements 3 and the sheet piles 5. As the excavation progresses, the props 7 are placed assembled in the form of frames spaced 1 meter apart in this example. The reinforced concrete beams formed in the tubular elements 3 and the struts 7 are calculated to withstand the stresses which are exerted on this structure during the excavation of the passage. Once this operation has been completed, the lost formwork 4 is inserted between the struts 7 and the tubular elements 3, a reinforcement is then introduced into the spaces provided between the sheet piles 5 and the formwork elements 4 and concrete is injected to fill these spaces and thus complete the reinforced concrete structure. The resistant structure is thus finished and it remains to carry out the covering using sheets 8 fixed inside the spacers and to be coated with the bottom of a raft covered with a coating 9.

The realization of the underground structure object of the invention therefore does not require any particular accessory infrastructure except supports for the tubular elements and sheet piles during the initial phase of the threshing process. As an indication, the advance of the tubular elements by threshing is between 8 and 12 cm / min so that a tubular element of 12 m can be inserted in about two hours.

Of course, this invention is not limited to a work of rectangular section. In addition, it is not necessary in all cases that the reinforced concrete structure extends around the entire straight section of the structure, the bottom of this section may not include such a structure since this party is not coerced.

The variant illustrated in FIG. 7 shows an underground structure whose section is substantially semi-circular. The reinforced concrete structure is identical to that of the passage illustrated in fig. 2 and comprises tubular elements 3 ′ alternating with sheet piling 5 ′, the structure being internally limited by lost formwork elements 4 ′ slipped between the tubular elements 3 ′ and props each formed by a hoop 17 whose ends are maintained separated by a spacer 18. The bottom of the structure does not have a reinforced concrete structure but is simply covered with a slab receiving a coating 9 '. This variant is obviously applicable to the example of FIG. 2 as it would also be possible to produce the variant of FIG. 7 with a reinforced concrete structure with tubes and sheet piles around the entire cross section of the structure.

Claims (4)

1. Underground passage work of constant cross-section comprising a reinforced concrete structure (2) surrounding at least a portion of the right cross-section area of the work which forms a free space above its bottom, this structure comprising cylindrical concrete beams made of concrete injected into tubes (3) which extend in parallel relationship one to the other along this work, as well as frame-like supports (7) arranged transversally inside of said structure, characterized in that the tubes (3) are placed at a separating distance from each other and are braced together with disposable shuttering or coffering elements (5) each of which is joined to two neighboring tubes so as to define the external face of a reinforced concrete wall, the latter being delimited inside by other disposable coffering elements or stays (4) located between these tubes and said frame-like supports, the latter being longitudinally spaced from each other.

2. The work according to claim 1, characterized in that the external face of each tubular element is provided with diametrically opposed longitudinal slides and that the longitudinal edges of the disposable coffering elements (5) connecting these tubes (3) are shaped so as to engage with these slides.

3. A method for building the underground passage work according to claim 1, characterized in successively sinking to a certain distance into the ground around the cross-sectional area of the work said tubes (3) and said disposable coffering elements (5), this cycle being repeated if needed until the total distance will correspond to the length of the work, filling said tubes with reinforced concrete, excavating the space defined by said tubular elements and the connecting disposable coffering elements, mounting said supports (7) while said excavating of the work progresses, inserting the other disposable coffering elements (4) between these supports and these tubes and filling with reinforced concrete the volumes defined by the disposable coffering elements (5) connecting together the tubes and the other disposable coffering elements (4) arranged tangentially thereto.

4. The method of claim 3, characterized in sinking said tubes (3) both ends being open and emptying them with a fluid under pressure before filling with reinforced concrete.

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