EP3359744B1 - Foundation structure - Google Patents

Description

Background of the invention

The present invention relates to retaining structures made in the ground, and in particular to structures intended to form port quay walls.

It relates more particularly, as described by the document JP H 08 193332 A , a retaining structure in the ground comprising a front part extending substantially vertically while delimiting a first portion of ground from a second portion of ground.

The invention finds its advantage in particular when the levels of the first and second portions of ground are substantially different, for example when the difference in height between the first and second portions of ground is of the order of 15 to 30 m.

This is the case when the first portion of ground is located under a body of water, the front part of the retaining structure then constituting a quay wall also delimiting the body of water from the second portion of ground.

Traditionally, the front part of such a retaining structure is a flat wall and part of the forces exerted by the second portion of ground on the front part is taken up by elongated metal tie rods which connect the flat wall to an anchoring curtain rear, parallel to the flat wall, and located in the second floor portion, at a distance from the flat wall, which ensures the stability of the structure. The rear anchoring curtain can be located more than 50 meters from the flat wall, and the metal tie rods can be positioned at a depth of around 5 meters. Conventionally, one begins by making the flat wall and the anchoring curtain in the second floor portion. Then the volume of soil is cleared over the distance separating the flat wall from the rear curtain, and over the depth at which the metal tie rods must be positioned.

It is therefore understood that the volume of soil that it is necessary to clear in order to be able to place the metal tie rods is very large, and this all the more so since the flat wall has a great length. In addition, after installing the metal tie rods, it is necessary to backfill the volume of soil that was previously cleared. In general, an underground water table is present, which must be lowered during the duration of the works.

These successive operations of lowering the water table and earthworks, which require moving very large volumes of soil, are particularly long, tedious and expensive.

The document JP H08193332A discloses a retaining structure having a front portion comprising vaulted walls and a rear portion comprising wall members having a greater depth than the vaulted walls.

Subject matter and summary of the invention

An object of the invention is to remedy the aforementioned drawbacks by proposing a retaining structure which is simpler and quicker to produce than that of the prior art, and which does not require the aforementioned earthworks.

• chaque paroi voûtée présentant un intrados en regard de la première portion de sol ainsi qu'un extrados en regard de la seconde portion de sol, et
• l'ouvrage de soutènement comporte en outre une partie arrière reliée à la partie avant et comprenant une pluralité d'éléments de paroi dont les plus grandes faces s'étendent verticalement dans la seconde portion de sol, chaque élément de paroi étant disposé entre deux parois voûtées adjacentes et étant transversal à la partie avant.

To do this, the invention relates to a retaining structure according to claim 1, in which the front part is in the form of a juxtaposition of vaulted walls extending in a longitudinal direction which is vertical,

• each vaulted wall having an intrados facing the first floor portion as well as an extrados facing the second floor portion, and
• the retaining structure further comprises a rear part connected to the front part and comprising a plurality of wall elements whose largest faces extend vertically into the second portion of ground, each wall element being arranged between two walls vaulted adjacent and being transverse to the front part.

It will be understood that, considered in a horizontal section plane, the juxtaposition of the vaulted walls of the front part has the form of a succession of arcs arranged side by side and whose intrados are turned towards the first floor portion.

The wall elements constitute planar tie rods which extend vertically from the ground surface to a predetermined depth. The wall elements are integral with the front part over their entire height. Their function is to take up the forces undergone by the vaulted walls and advantageously replace the slender metal tie rods and the rear curtain of the prior art.

The wall elements are advantageously made from the ground surface. Consequently, according to the invention and contrary to the prior art, the laying of the tie rods is carried out without having to clear and then backfill a large quantity of soil. The invention therefore makes it possible to execute the retaining structure much more quickly once the earthwork operations are dispensed with.

Preferably, each wall element is arranged between two adjacent vaulted walls, being orthogonal to the front part.

Advantageously, the upper level of the front part corresponds substantially to the upper level of the rear part. In other words, the upper faces of the vaulted walls are substantially at the same level as the upper faces of the wall elements.

Advantageously, the front part comprises two vertical end edges, and the rear part further comprises two other wall elements which are transverse to the front part and arranged on either side of said plurality of wall elements in s extending from the vertical end edges of the front part.

Advantageously, the wall elements are flat. Preferably, the front part has a longitudinal direction and the wall elements are perpendicular to said longitudinal direction of the front part.

Advantageously, the wall elements are parallel to each other. Preferably, the wall elements are regularly spaced from each other.

According to the invention, the wall elements have a height which is strictly less than the height of the front part. In other words, the depth of the wall elements is strictly less than that of the front part.

Thus, over the height of the wall elements, the retaining structure according to the invention behaves like a monolithic structure: each vaulted wall making up the front part works as a vault like a circular wall, blocked at its ends by the wall elements , which work like flat tie rods. The assembly above, including the volume of soil contained between the wall elements, functions similarly to that of a “gravity wall”. This makes it possible to substantially reduce the intensity of the bending moments applied to the front part, and to reduce the value of the displacements. In addition, below the wall elements, the retaining structure behaves like a conventional flat wall.

In other words, the retaining structure according to the invention exhibits hybrid behavior.

Preferably, the height of the front part is substantially equal to twice the greatest height of the wall elements. Within the meaning of the invention, the "height" is considered in a vertical direction, while the "length" of the wall elements is considered in a horizontal direction.

The greatest height of the wall elements can be constant over the entire length of said wall elements. However, and advantageously, considered according to its length, at least one of the wall elements comprises a first end connected to the front part, and a second end opposite the first end, and the height of the wall element decreases from the first end towards the second end of said wall element. This decreasing height has the advantage of reducing the concentration of stresses at the location of the junction between the wall element and the vaulted walls which are immediately adjacent to it. Another interest is to support the diffusion of tensile stresses along the wall elements forming flat tie rods. Yet another advantage is to reduce the quantity of materials necessary to form the rear part, which makes it possible to reduce the cost of the retaining structure. Preferably, the profile of the underside of the wall elements is stepped.

Preferably, the length of the wall elements is greater than the greatest height of said wall elements.

Advantageously, the distance between two adjacent wall elements is less than the length of one of the wall elements. Preferably, the distance between two adjacent wall elements is substantially equal to half the length of one of the wall elements. One advantage is to improve the absorption of forces by the rear part of the retaining structure.

According to a preferred embodiment, at least two vaulted walls are connected to each other and to one of the wall elements by a coupling element which has a first connecting part connected to the wall element and second and third connecting parts connected to the two vaulted walls. It is understood that the arched walls act in compression on the coupling element.

Advantageously, the front and/or rear parts are made of reinforced concrete.

Preferably, the vaulted walls comprise reinforcement cages which are arranged next to each other. Furthermore, when the rear part also contains reinforcements, these are connected to the reinforcement cages of the first part, preferably by means of the coupling elements, so as to achieve structural continuity between the reinforcements of the front parts. and back.

According to a first embodiment, the front part and/or the rear part is a molded wall. When the front part is a molded wall, at least some of the vaulted walls are preferably made up of a juxtaposition of plane unit screens arranged in an arc of a circle. The diaphragm walls are conventionally executed by alternating or successive elementary panels. You can use formwork at the ends, such as those described in the document EP 0 101 350 . Alternatively, with tools of the wall cutter type, the connection between panels can be obtained by re-biting the concrete of the panel already poured.

According to a second embodiment, the front part is made of reinforced concrete, while the wall elements comprise sheet piles.

According to another variant, the rear part is produced using a "soil-mixing" technique, combining a step of excavating a trench and mixing in situ the soil in place of the trench with a binder . If necessary, sheet piles can then be placed in the trench.

According to yet another variant, the rear part is produced using the grout wall technique, known elsewhere, in which the reinforcements may possibly be installed.

The present invention also relates to a port quay comprising at least one retaining structure according to the invention, in which the first portion of ground is located under the bottom of a body of water so that the front part also delimits the plane of water from the second portion of soil.

This port quay can be a maritime quay, a river quay, or any other type of quay in contact with a body of water.

Preferably, but not necessarily, the bottom of the body of water is between the lower level of the rear part and the level of the lower end of the forward part.

Advantageously, the port quay according to the invention further comprises a first rail which is transverse to the wall elements of the rear part while being supported by several of said wall elements, and the port quay further comprises a second rail parallel to the first rail.

These two rails constitute a track allowing freight handling cranes, such as container gantries, to move parallel to the longitudinal direction of the front part of the structure.

Preferably, the first rail is preferentially fixed to the wall elements.

Preferably, but not exclusively, the second rail is supported by the front part. Also, thanks to the invention, the first and second rails are supported by the retaining structure. Preferably, the rails are also integral with the retaining structure. Consequently, the wall elements form crosspieces, which makes it possible to ensure a constant spacing between the two rails.

In addition, the weight of the container crane is advantageously taken up by the retaining structure, which has the double advantage of reducing the vertical forces to be taken into account for the dimensioning of the front part, and of avoiding the risk of movement. differentials between the two rails, likely to occur with retaining structures of the prior art.

Brief description of the drawings

• la figure 1 est une vue en perspective d'un quai portuaire selon l'invention constitué d'un ouvrage de soutènement selon un premier mode de réalisation de l'invention ;
• la figure 2 est une vue latérale en coupe du quai portuaire de la figure 1 , sur laquelle ont été représentés un portique à conteneurs installé sur une paire de rails supportée par l'ouvrage de soutènement ;
• la figure 3 est une vue de dessus du quai portuaire de la figure 1 ;
• la figure 4 est vue une latérale en coupe d'une variante du quai portuaire de la figure 1 comprenant un ouvrage de soutènement selon un deuxième mode de réalisation de l'invention ;
• les figures 5A et 5B sont des graphiques comparatifs qui illustrent les valeurs de déplacement et de moments fléchissant en fonction de la profondeur ;
• la figure 6 est une vue de dessus en coupe du quai portuaire selon un premier exemple de réalisation de l'invention ; et
• la figure 7 est une vue de dessus en coupe du quai portuaire selon un deuxième exemple de réalisation de l'invention.

The invention will be better understood on reading the following description of embodiments of the invention given by way of non-limiting examples, in which:

• the figure 1 is a perspective view of a port quay according to the invention consisting of a retaining structure according to a first embodiment of the invention;
• the figure 2 is a cross-sectional side view of the harbor quay of the figure 1 , on which a portico with containers installed on a pair of rails supported by the retaining structure;
• the picture 3 is a top view of the harbor quay of the figure 1 ;
• the figure 4 is a cross-sectional side view of a variant of the port quay of the figure 1 comprising a retaining structure according to a second embodiment of the invention;
• the figures 5A and 5B are comparative graphs which illustrate the values of displacement and bending moments as a function of depth;
• the figure 6 is a sectional top view of the port quay according to a first embodiment of the invention; and
• the figure 7 is a sectional top view of the port quay according to a second embodiment of the invention.

Detailed description of the invention

On the picture 1 , there is illustrated a port quay 10 according to the invention, which comprises a retaining structure 12 in a ground S according to a first embodiment. The retaining structure 12 comprises a front part 14 which extends substantially vertically, and which delimits a first portion of ground S1 from a second portion of ground S2.

By referring to figure 1 and 2 , it can be seen that the first portion of ground S1 is located under the bottom F of a body of water P and that the front part 14 has a depth greater than that of the body of water. It is therefore understood that the front part 14 of the retaining structure 12 also delimits the body of water P from the second portion of soil S2.

It is understood that the front part 14 of the retaining structure constitutes a retaining wall whose function is to prevent the second portion of soil from collapsing into the body of water P.

As can be seen on the figure 2 , the height H1 of the front part 14 of the retaining structure 12 is strictly greater than the height H2 of the body of water P, it being understood that the height H2 of the body of water P is defined between the bottom F and the surface of the body of water P. More specifically, the front part 14 of the retaining structure 12 extends vertically below the bottom F of the body of water P over a height H3. Also, the front part 14 of the retaining structure 12 delimits the portion of ground S1 from the second portion of ground S2 over this height H3.

Furthermore, the front part 14 of the retaining structure 12 extends vertically above the surface of the body of water P over a height H4.

In this non-limiting example, the height H1 of the front part 12 is 43 meters, the height H2 of the body of water is of the order of 25 meters, the height of the emerged part H4 of the front part 14 is the order of 6 meters. Finally, the height H3 of the portion of the front part 14 which extends under the bottom of the body of water P is of the order of 12 meters.

According to the invention, the front part 14 of the retaining structure 12 is in the form of a juxtaposition of vaulted walls 16 which extend in a longitudinal direction which is vertical. The vaulted walls are aligned by being arranged side by side so as to form a continuous wall which extends along a mean vertical plane X1 which extends along the longitudinal direction of the front part. As shown in the picture 3 , each vaulted wall 16 has a cross section, taken in a horizontal plane, which generally has the shape of an arc of a circle.

Each vaulted wall 16 has an intrados 18 which faces the first portion of ground S1, and also towards the body of water P. Each vaulted wall 16 also has an extrados 21, opposite to the intrados 18, which is look of the second portion of floor S2.

In this example, each vaulted wall 16 has a thickness E1 which is of the order of 1 meter. It is further understood that each arched wall 16 extends vertically from the surface along substantially the entire height H1 of the front part 14 of the retaining structure 12. Still in this example, each arched wall 16, considered in a horizontal plane , has a radius of curvature R, which is of the order of 15 meters.

The retaining structure 12 further comprises a rear part 20 which is integral with the front part 14 so as to form a one-piece structure. The rear portion 20 includes a plurality of wall members 22 formed in the ground and which extend vertically from the ground surface to a predetermined depth. It is therefore understood that the largest faces 24 extend vertically in the second portion floor S2. In the first embodiment illustrated in figure 2 , the largest face 24 of the wall elements 22 has a substantially planar and rectangular shape.

By referring to the figure 2 , it can be seen that the upper level of the front part corresponds substantially to the upper level of the rear part. In other words, the wall elements 22,26 extend vertically from the upper level of the front part. What is more, the wall elements 22 are integral with the front part 14 over their entire height.

As can be seen on the picture 3 , each wall element 22 is secured to the front part by being arranged between two adjacent vaulted walls 16 , while being transverse to the front part 14. More specifically, in this first embodiment, the wall elements 22 extend in vertical planes X2, which are perpendicular to the mean plane X1 in which extends the front part 14 of the retaining structure 12.

Furthermore, the wall elements 22 are parallel to each other, the distance d between two successive wall elements 22 being of the order of 15 meters.

In this first embodiment, the front part 14 comprises two vertical end edges 14a and 14b, opposite to each other, as illustrated in picture 3 . The rear part 20 further comprises two other wall elements 26 which are also transverse to the front part 14, and which are arranged on either side of the plurality of wall elements 22. These other wall elements 26 s extend from the end edges 14a, 14b of the front part 12, so that all the wall elements 22,26 are parallel to each other.

More specifically, in this first embodiment, the wall elements 22,26 are identical and parallel to each other, so that we will limit ourselves to describing the wall element 22 which is illustrated in picture 2 .

Advantageously, the wall elements 22,26 have a greater height H5M, which, in this example, is constant over the entire length of the wall elements. In addition, all the wall elements 22,26 have the same greater height. However, without leaving the In the context of the present invention, the wall elements could have different greatest heights.

The greatest height H5M is strictly less than the height H1 of the front part 14. What is more, the depth of the wall elements 22.26 is strictly less than that of the front part 14.

This conformation has the effect that, according to the height H5M, the retaining structure behaves like a circular wall, while below the wall elements 22,26, the retaining structure behaves like a flat wall.

Moreover, in the example of the figure 2 , it can be seen that the level of the bottom F of the body of water P is between the lower level 14a of the front part 14 and the lower level 20a of the rear part 20. The lower level 14a of the front part 14 corresponds to the lower end of the vaulted walls, while the lower level of the rear part corresponds to the underside of the wall elements 22,26.

In this example, the height H1 of the front part is substantially equal to twice the greatest height H5M of the wall elements 22.26. In this example, the wall elements extend along a length L which is oriented horizontally. The length L of the wall elements 22,26 is greater than the greatest height H5M of said wall elements, as illustrated in figure 2 .

In addition, the distance d between two adjacent wall elements 22,26 is substantially equal to half the length L of the wall elements 22,26. Such a configuration makes it possible to improve the retaining properties of the retaining structure according to the invention.

Referring again to the picture 3 , it can be seen that at least two adjacent vaulted walls 16 are connected to each other and to one of the wall elements 22 by a coupling element 30 which has a first connecting part 30a connected to the element wall 22 and first and second connecting parts 30b, 30c connected to the two adjacent vaulted walls. This coupling element 30 facilitates the connection between the vaulted walls and the connecting element.

Referring again to the figure 2 , it is noted that the port quay 10 further comprises a first rail 40 and a second rail 42, parallel to the first rail 40 on which a container gantry crane 50 can move parallel to the front part 14, in order to load a container cargo ship 52.

The first rail 40 is transverse to the wall elements 22.26 while being supported by said wall elements 22.26. The second rail 42 is meanwhile, in this example, supported by the front part 14. Without departing from the scope of the present invention, the second rail 42 could also be supported by the wall elements 22,26. In this example, the first and second rails 40,42 are fixed to the retaining structure 12.

On the figure 4 , there is illustrated another port quay 10' according to the invention, which comprises a retaining structure 12' according to a second embodiment of the invention.

Considered along its length L, each wall element 22' has a first end 22'a which is connected to the front part 14' and a second end 22'b which is opposite to the first end 22'a.

The retaining structure 12' according to this second embodiment differs from the first embodiment in that the wall elements 22' of the rear part 20' have a non-uniform height.

As illustrated in figure 4 , considered along the length of the wall element, the height of said wall element 22 decreases between the first end 22'a and the second end 22'b of the wall element 22. In the example of the figure 4 , the lower face 22'c of the wall element 22' has a stepped shape, the greatest height H5M of the wall element 22' being close to the front part 14'.

We will now describe an example of a method for producing the port quays described above.

To make the port quay 10, one begins for example to make the front part 14 of the retaining structure 12. To do this, one forms in the ground S a diaphragm wall of depth H1 whose cross section, taken in a plane horizontal, has the shape of a succession of arcs, as represented in picture 3 . This diaphragm wall is made of reinforced concrete. To do this, we can use a drilling tool, such as the one described in EP 2 295 648 .

Then, or concomitantly, the wall elements 22,26 are made, either in the form of diaphragm walls, or else by making excavations using a “soil-mixing” technique in which sheet piles are introduced. This can be done using a drilling and mixing tool, such as the one described in FR 2 889 608 . The coupling elements 30 are also placed between the wall elements 22 and the vaulted walls 16

In the examples of figure 6 and 7 , the coupling elements 30′, 30″ are built with the tools used to make the front part.

This is for example a diaphragm wall tool implementing formwork such as those described in the document EP 0 101 350 , which make it possible to make the connections between the coupling element and the vaulted walls.

The figure 6 illustrates a first embodiment of the coupling elements 22 30'. In this first example, the first connecting part 30'a is coupled with the wall element 22 by shape cooperation. In this first example, the wall element 22 is made of a diaphragm wall with continuous reinforcements, as described in the document EP 0 833 987 for example. It can be seen that the reinforcing cage 31' of the coupling element 30' is connected with the reinforcing cage 23 of the wall element 22. Each of the second and third connecting parts 30'b, 30'c is also provided with a reinforcing cage and is in the form of a connecting arm which is coupled with one of the vaulted walls 16 by shape cooperation.

In the second embodiment illustrated in the figure 7 , the 30" coupling element is similar to that of the figure 6 except that the second and third connecting parts 30"b and 30"c have the shape of a recess and not of a connecting arm. The vaulted wall 16 which is connected to the second connecting part 30"b consists of two unitary elements 16 ₁ and 16 ₂ connected to each other.

Furthermore, in this second embodiment, the wall element 22 comprises a wall of sheet piles 25 connected to the reinforcement cage 31" of the coupling element 30". This sheet pile wall can be driven directly into the ground, or placed in the excavation by the “soil-mixing” technique, as described above, or even as a grout wall well known elsewhere.

To make the wall elements 22' of the second embodiment of the figure 4 , four adjacent trenches are dug, the respective heights of which decrease between the first end 22'a and the second end 22'b. We then obtain the staircase shape illustrated in figure 4 .

On the figure 5A , the curve G1 illustrates the displacement in millimeters of the retaining structure 12 of the figure 1 as a function of the depth, measured from the surface of the body of water P. The curve G2 illustrates the displacement of a retaining structure according to the prior art described above.

On the figure 5B , the curve M1 illustrates the value of the bending moments undergone by the retaining structure 10 of the figure 1 depending on the depth. Curve M2 illustrates the value of the bending moments undergone by the retaining structure according to the prior art described above.

It emerges from the calculations carried out that the retaining structure according to the invention has displacements and bending moments which are, in absolute value, substantially lower than those of the previous structure.

Claims (15)

1. A retaining structure (12, 12') in the ground (S) including a front part (14) extending substantially vertically while delimiting a first ground portion (S1) from a second ground portion (S2), wherein

   the front part (14) is in the form of a juxtaposition of arched walls (16) extending along a longitudinal direction which is vertical,

   each of said arched walls (16) has an intrados (18) facing the first ground portion (S1) as well as an extrados (21) facing the second ground portion (S2),

   the retaining structure (12) further includes a rear part (20) connected to the front part (14) and comprising a plurality of wall elements (22) whose largest faces (24) extend vertically in the second ground portion (S2), each wall element (22) being disposed between two adjacent arched walls (16) and being transverse to the front part (14), characterized in that the wall elements (22) have a height (H5M) strictly lower than the height (H1) of the front part (14), whereby the depth of the wall elements is strictly less than that of the front part.
2. The retaining structure according to claim 1, wherein the front part (14) includes two vertical end edges, and wherein the rear part (20) further includes two other wall elements (26) which are transverse to the front part (14) and disposed on either side of said plurality of wall elements (22) extending from the vertical end edges (14a, 14b) of the front part.
3. The retaining structure according to claim 1 or 2, wherein the wall elements (22, 26) are planar.
4. The retaining structure according to any one of the preceding claims, wherein the wall elements (22, 26) are parallel to each other.
5. The retaining structure according to any one of the preceding claims, wherein the height (H1) of the front part is substantially equal to twice the greatest height (H5M) of the wall elements (22, 26).
6. The retaining structure according to any one of the preceding claims, wherein, considered along its length (L), at least one of the wall elements (22') includes a first end (22'a) connected to the front part (14'), and a second end (22'b) opposite to the first end (22'a), and wherein the height of the wall element (22) decreases between the first end (22'a) and the second end (22'b) of said wall element (22).
7. The retaining structure according to any one of the preceding claims, wherein the length (L) of the wall elements (22, 26) is greater than the greatest height (H5M) of said wall elements.
8. The retaining structure according to any one of the preceding claims, wherein the distance (d) between two adjacent wall elements (22, 26) is less than the length (L) of one of the wall elements (22 ,26).
9. The retaining structure according to any one of the preceding claims, wherein at least two adjacent arched walls (16) are connected to each other and to one of the wall elements (22) by a coupling element (30, 30', 30") which has a first connecting part (30a, 30'a, 30"a) connected to the wall element (22) and second and third connecting parts (30b, 30c; 30'b, 30'c; 30"b, 30"c) connected to the two adjacent arched walls.
10. The retaining structure according to any one of the preceding claims, wherein the front (14) and/or rear (20) parts are made of reinforced concrete.
11. The retaining structure according to any one of the preceding claims, wherein the front part (14) and/or the rear part (20) is a diaphragm wall.
12. The retaining structure according to any one of the preceding claims, wherein the front part (14) is made of reinforced concrete, while the wall elements include sheet piles.
13. A harbor dock (10) including at least one retaining structure (12) according to any one of the preceding claims, wherein the first ground portion (S1) is located under the bottom (F) of a water body (P) so that the front part (14) delimits the water body (P) of the second ground portion (S2).
14. The harbor dock according to claim 13, characterized in that it further includes a first rail (40) which is transverse to the wall elements (22, 26) of the rear part while being supported by several of said wall elements (22, 26), and in that the harbor dock further includes a second rail (42) parallel to the first rail.
15. The harbor dock according to claim 14, characterized in that the second rail (42) is supported by the front part (14).

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