Classifications

• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
  • E02D29/00—Independent underground or underwater structures; Retaining walls
  • E02D29/045—Underground structures, e.g. tunnels or galleries, built in the open air or by methods involving disturbance of the ground surface all along the location line; Methods of making them

Definitions

• the invention belongs to the field of construction and public works. It relates to an underground structure, more particularly for the passage of vehicles below an inclined ramp.
• the invention also covers prefabricated elements, especially adapted to the realization of such a work.
• the railway lines are built on a platform that follows, as far as possible, the ground level and they are crossed by many crossings that must be removed, for security reasons, when the line remains active.
• underground passages are generally avoided and it is preferred to build a bridge over the tracks.
• This bridge must pass a relatively high height, given the size necessary for the passage of trains and supply lines. It is connected at its ends to two inclined ramps.
• the object of the invention is therefore to solve such problems by means of a standardized construction method which makes it possible to considerably reduce the production costs.
• such an underground passage made below an inclined ramp consists of several adjacent parallel-axis ducts, each limited by a wall consisting of juxtaposed prefabricated elements resting on a laying surface and comprising , in cross section, at least three elements, respectively two side members each comprising a substantially vertical side wall, a lower part bearing on the laying surface and an upper part, and at least one curved upper element resting on the elements of side and forming a vault resting on the upper parts of the two side elements and, all of the ducts being covered with a backfill having an upper part forming a platform whose level may vary with respect to the ground, the dimensions of the prefabricated elements constituting each of the adjacent ducts are determined according to the posi the duct along the platform so that each duct has, in its longitudinal median plane passing through its axis, a height with respect to the ground lower than that of the platform and that the vaults covering two adjacent ducts have a common tangent plane extending at any point to a minimum height below the platform
• the upper part of the embankment covering the ducts is inclined so as to form an access ramp to the deck of a bridge at a height determined relative to the level of the laying surface of the ducts.
• the structure comprises a main pipe having a height determined so as to limit a maximum clearance gauge and two lateral ducts having a lower height, and the assembly is covered with a backfill whose upper part form a platform having two access ramps inclined symmetrically on both sides of the main duct and connected to the top of the main duct.
• the invention also allows the realization of an underground structure with several passage sections, below a fill through a valley whose floor comprises a central portion placed at a lower level and two side portions whose level increases in away from the central portion, said valley being traversed by an embankment whose lower part forms a substantially flat platform.
• the embankment may be traversed by a structure comprising a main pipe of maximum height for crossing the central portion of the valley and at least two lateral ducts placed respectively on either side of the main pipe and presenting each a lower height, less than the height of the platform relative to the ground at the median plane of the duct considered.
• the underpass comprises two adjacent ducts separated by a common intermediate side consisting of elements placed one after the other, each having a lower part forming a base plate on the laying surface and an upper part carrying two support members spaced apart on either side of a longitudinal median plane of the pedestal, on which rest, respectively, the upper elements of the two ducts, said support members being placed at two different levels by relative to the laying surface of the pedestal.
• the adjacent ducts of two adjacent ducts may also be constituted, respectively, of two series of prefabricated elements placed one after the other and having two different heights.
• the elements of the two series are placed back to back in pairs and are interconnected by at least one cross member.
• the invention has the advantage of allowing the use of standardized elements for which the manufacturer normally has several molds to achieve, in particular, elements of different heights.
• each duct comprises an upper element tangentially connected to a side element along a joint plane orthogonal to the connecting parts of the two elements
• two adjacent ducts side elements of different heights which are provided with upper connection parts having the same profile and the same orientation of joint plane, the two ducts being covered by identical upper elements made on the same mold.
• side elements of the same height on which rest upper elements with different arrows it is also possible to use side elements of the same height on which rest upper elements with different arrows.
• Figure 1 shows, in cross section, a first application of the invention.
• Figure 1a is a detail view of an intermediate support.
• Figure 2 shows, in cross-section, a second application of the invention.
• FIG. 3 shows another embodiment of an underground passage according to the invention.
• Figure 4 is a partial view of another embodiment.
• Figure 5 is a detail view of the embodiment of Figure 4.
• Figure 6 shows another application of the invention.
• FIG. 1 diagrammatically shows, in cross-section, a first application of the invention in the case of a ramp for access to a bridge 1 comprising an apron 11 resting on abutments 12. Often, to leave a tie the minimum air H between the water level 13 and the apron 11, it must be at a relatively high height h above the ground level 14.
• an access ramp 2 which is inclined to connect the ground level to that of the deck 11. It is economical to realize this ramp by means of a simple embankment placed on the ground 14 and whose height gradually increases to the level of the deck 11. As the slope of the ramp 2 must remain quite low, for example, 5%, the embankment 21 has a fairly long length. However, it often happens that a road runs along the river and must, therefore cross the embankment 21, along the abutment 12 at the bridge 1.
• this transverse passage consists of a bridge having an inclined span resting on two abutments and constituting the upper end of the ramp which connects to the deck 11.
• the same inventor has point and developed, for several years, a technique of construction of underground passages from prefabricated elements, respectively two elements of spaced apart piers resting on the ground by an enlarged base and a curved upper element which is connected tangentially to the upper ends of the elements of piers.
• the prefabrication technique makes it possible to produce molded elements of perfect quality which can therefore be calculated so as to be particularly thin and, to meet various needs, it is advantageous to have in advance several mold sets of which the dimensions vary to achieve ducts of different heights and widths. It is thus possible to produce a range of ducts whose height may vary, for example, between 1.75 and 3.5 m and which limits useful surfaces, for example, from 3.5, 5, 7.5, 10, 12.5 m 2 . It is advantageous, on the other hand, for the piers elements to be curved so as to be connected tangentially to the upper element in order to produce an ovoid section which can be slightly deformed under the load of the embankment while bearing laterally on the latter. this.
• Each duct is then bounded by a tubular wall 3 comprising, in cross-section, an upper element 31 resting on two wall elements 32, 33.
• the upper element 31 and the upper parts of the wall elements 32, 33 are curved and have the same radius of curvature so as to connect tangentially to form a continuous arch.
• the entire wall 3 rests on a flattened surface formed on the ground 14 and forming a horizontal platform 15.
• Each element of the wall 32, 33 is provided with a base 36 allowing the wall to stand straight by itself when he is lying on the ground.
• the intermediate wall 33 placed between two adjacent ducts A, B may consist of a single element having two upper supports, respectively 35a, 35b, for the vault elements 31a, 31b two ducts A, B, which are formed on either side of the median plane of the wall 33.
• the upper supports 35a, 35b are formed on the intermediate platform 33, at different heights (h1, h 2 ) relative to the laying platform 5, so that the height of the vault 31a, 31b decreases as one moves away from the abutment 12 of the bridge. It can be seen that, to produce such plates, the same molds can be used as in the technique of patent EP 0 202 256 simply by adapting the upper part so as to offset the supports 35a, 35b in height relative to one another. to the other.
• the height of the piers 33c, 34 of the duct D farthest from the abutment 12 will be determined so as to clear a template G of minimum height, the other ducts having a greater height.
• This minimum height may correspond to the road gauge, the highest sections A and B being used for the passage of a railway line or for a motorway. But the lower section can also be used for pedestrians or cyclists.
• the upper supports 35a, 35b of the side members have joint planes of the same inclination, so that the upper elements 31 may be identical, even if they rest on piers of different heights.
• Figure 2 shows the application of the invention to the passage of a railway for the replacement of a level crossing.
• it is necessary to make a backfill whose upper part forms two ramps inclined symmetrically on either side of the track E.
• the clearance gauge that must be left for the passage of two rail tracks is relatively important since It is necessary to take into account the height of the trains increased by that of the catenaries 16 carrying the electric lines.
• each intermediate platform 33 is provided, at its upper part, two supports 35a, 35b placed at different heights and on which rest the vault elements 31a, 31b of the two adjacent ducts A 1 , B 1 .
• the heights of the two ducts are determined so that their tangent planes are inclined with respect to the horizontal platform 15 of a sufficient angle so that, after completion of the access ramp 2, it passes a minimum height above the vault 31a, 31b of the conduit, to provide a backfill cover of thickness e sufficient to distribute the forces applied on the wall.
• one of the advantages of this buried construction technique lies in the interaction between the embankment and the concrete wall which may have some flexibility, especially if it is articulated. The embankment thus makes it possible to distribute the load and to dampen the vibrations due to the circulation of the vehicles both inside the ducts and on the crossing ramp of the buried passage.
• the embankment 21 has, at the side piers, a fairly reduced height, it may be preferable to ignore the flexibility of the wall and, on the contrary, to provide the vault elements 31 b 31c ribs 31 'which allow to apply vertical forces on the upper ends of the side piers.
• the bases 36 of the wall elements 32, 33 are advantageously connected by concrete longitudinal joints or by a raft 37 cast in place.
• the entire structure thus relies on a continuous base that distributes the applied loads over a large area and thus withstands differential settlements.
• Such an advantage is particularly interesting for the realization of an underground passage on a relatively unstable ground, which is quite common along the river or along the tracks.
• FIG. 3 shows an exemplary embodiment of a structure with two passage sections comprising two contiguous ducts A, B each limited by a wall comprising, in cross-section, an upper element 31 resting on two pedestal elements. 32, 32 '.
• the side members 32'a, 32'b placed on the adjacent sides of the two ducts A, B are advantageously connected by two cross members, upper 38 and lower 38 ', respectively.
• the two adjacent elements 32'a, 32'b may be slightly spaced so as to provide a space between them in which extend reinforcements left in waiting at their base and which are embedded in a sealing mortar so as to form a lower crossbar 38 '.
• the two elements can also be provided with waiting armatures which are embedded in a reinforced concrete crossmember 38 cast in place.
• the adjacent elements 32'a, 32'b placed back to back are secured in pairs and behave as a single element.
• each duct A, B may be constituted by a raft 37a, 37b cast in place by drowning the pending reinforcements left on the inner sides of the bases 36 of the side elements in order to constituting, over the entire width of the duct, a continuous soleplate making it possible to distribute the load over a very large area and, thus, to avoid differential settlements.
• the wall elements 32a, 32b which have different heights hi, h 2 form, at their upper ends 35a, 35b, supports having a joint plane inclined at the same angle, for example 45 °.
• a joint plane inclined at the same angle for example 45 °.
• FIGS. 4 and 5 Such an embodiment has been shown in FIGS. 4 and 5. It can be seen that, in this case, the two adjacent ducts A, B are separated by an intermediate crossmember 33 of symmetrical shape comprising upper supports 35 arranged at the same level. On the other hand, the vault elements 31a, 31b have arrows f 2 different so as to vary the height of the two ducts A, B.
• the supports 35a, 35b of the two vault elements 31a, 31b advantageously form articulations that allow, if necessary, to vary the inclination of the vault at birth.
• the invention therefore provides multiple possibilities and allows, from standardized elements, to adapt to the most diverse situations.
• the invention is not limited only to the case of an embankment forming an inclined ramp but can also be applied to the crossing of a valley comprising a relatively deep central portion in which passes, for example, the main bed of a river and two lateral parts that can be covered by the river in case of flood.
• it is generally necessary to construct a multi-pile viaduct comprising a central span above the main bed and lateral bays allowing the passage of the river in case of widening of its bed.
• the invention makes it possible to very economically solve such a problem by replacing the viaduct with a backfill whose upper part forms a substantially horizontal running platform, but whose height may vary with respect to the natural terrain.
• FIG 6 there is shown, by way of example, such an application.
• the main bed of the river is crossed by a central duct Ai flanked by lateral ducts B 1 , Ci which rest on a laying surface 15b, 15c placed at a higher level than in the central part, and whose elements are dimensioned. so as to give the lateral duct a lower height, the assembly being covered with a backfill 21 limited by a platform 2 which passes at a minimum height above the vaults of the ducts A 1 , B 1 , Ci.
• the adjacent side members are connected by a cross member 38, as described above.
• each duct having a height determined according to the height of the embankment with respect to the ground, at its plane longitudinal median.

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• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Mining & Mineral Resources (AREA)
• Paleontology (AREA)
• Civil Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Structural Engineering (AREA)
• Bridges Or Land Bridges (AREA)
• Lining And Supports For Tunnels (AREA)

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• 2006
  • 2006-03-10 AU AU2006340312A patent/AU2006340312A1/en not_active Abandoned
  • 2006-03-10 EP EP06726234A patent/EP1994231A1/de not_active Withdrawn
  • 2006-03-10 WO PCT/FR2006/050210 patent/WO2007104839A1/fr not_active Ceased

Non-Patent Citations (1)

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