Title of Invention	STABILIZED SOIL STRUCTURE AND FACING ELEMENTS FOR ITS CONSTRUCTION
Abstract	The facing element for a stabilized soil structure comprises a body (4) of cast material inside which a path is formed for a reinforcement strip (2) between two points of emergence (6) situated on a rear face (7) of the element. This path includes two rectilinear portions (8) which are respectively adjacent to the two points of emergence and are each arranged so as to position the strip in the same plane of emergence perpendicular to the rear face, two curved portions (9) which respectively continue the two rectilinear portions and are arranged so as to deviate the strip from the plane of emergence, and a connection portion which joins the two curved portions to one another and has at least one loop (10) situated outside the plane of emergence.

Title of Invention

STABILIZED SOIL STRUCTURE AND FACING ELEMENTS FOR ITS CONSTRUCTION

Abstract

The facing element for a stabilized soil structure comprises a body (4) of cast material inside which a path is formed for a reinforcement strip (2) between two points of emergence (6) situated on a rear face (7) of the element. This path includes two rectilinear portions (8) which are respectively adjacent to the two points of emergence and are each arranged so as to position the strip in the same plane of emergence perpendicular to the rear face, two curved portions (9) which respectively continue the two rectilinear portions and are arranged so as to deviate the strip from the plane of emergence, and a connection portion which joins the two curved portions to one another and has at least one loop (10) situated outside the plane of emergence.

Full Text	The present invention relates to the construction of stabilized soil or reinforced earth structures. This building technique is commonly used to produce structures such as retaining walls, bridge abutments, etc. A stabilized soil structure combines a compacted fill, a facing, and reinforcements usually connected to the facing. The reinforcements are placed in the soil with a density dependent on the stresses that might be exerted on the structure, the thrust forces of the soil being reacted by the soil-reinforcements friction. The invention more particularly concerns the case where the reinforcements are in the form of strips of synthetic material, for example based on polyester fibres. The facing is most often made up of prefabricated concrete elements, in the form of slabs or blocks, juxtaposed to cover the front face of the structure. There may be horizontal steps on this front face between different levels of the facing, when the structure has one or more terraces. The reinforcements placed in the fill are usually secured to the facing by mechanical connecting members that may take various forms. Once the structure is complete, the reinforcements distributed through the fill transmit high loads, in some cases of up to several tonnes. Their connection to the facing needs to be robust in order to maintain the cohesion of the whole. The connecting members exhibit risks of degradation. They are often sensitive to corrosion due to moisture or to chemical agents which are present in or which have infiltrated into the fill. The connecting members are sometimes made on the basis of resins or composite materials so that they corrode less readily. However, their cost is then increased, and it is difficult to give them good mechanical properties. It is therefore desirable to be able to dispense with connecting members between the facing element and the reinforcements of the structure. In some systems, the facing elements are configured in such a way as to present at least one passage intended to receive a reinforcement strip. In US-A-5 839 855, the passage is in the shape of a C within the thickness of the facing element in the form of a panel. When the strip is put in place, its two sections emerging from the facing element are located in two parallel horizontal planes offset in the vertical direction. This condition of emergence of the strips from the panel is not ideal because it makes it necessary . to increase the number of filling and compacting operations, which complicates and prolongs the implementation of the work. This does not easily permit homogeneous tensioning of the strips, because the strip is not retained by the panel when its lower portion is covered with fill. For these reasons, it is generally desirable for the strips to emerge from the facing element in the same horizontal plane. In addition, the C-shaped path of the reinforcement strips is not optimal in terms of the robustness of the anchoring when stressed. The curve of the path near the point of emergence of the strip weakens its anchoring to the element because it causes working in tension of a small thickness of concrete, which, is not a good way of Stressing this material. A similar problem arises with a facing element of the type described in FR-A-2 812 893. This element also has a pre-formed path in the shape of a C. In addition, this C-shaped path is arranged so that each portion of the reinforcement strip emerges from the element oriented in a vertical plane. This is unsatisfactory because the strip placed on the ground positions itself naturally in a horizontal plane, so that each portion of the strip in the fill twists one quarter of a turn. Such twisting is unfavourable in terms of the mechanical behaviour of the reinforcement. It is an object of the present invention to propose a novel method of anchoring reinforcement strips to a facing of a stabilized soil structure, making it possible to reduce the incidence of the problems set out above. The invention thus proposes a stabilized soil structure, comprising a fill, reinforcement strips extending through a reinforced zone of the fill situated behind a front face of the structure, and a facing placed along said front face, the reinforcement strips being anchored to the facing in respective anchoring regions. In at least one anchoring region, the facing incorporates a path formed for a reinforcement strip between two points of emergence situated on a rear face of the facing adjacent to the fill. This path includes two rectilinear portions respectively adjacent to the two points of emergence and each arranged to position the strip in a common plane of emergence perpendicular to said rear face, two curved portions respectively continuing the two rectilinear portions and arranged to deviate the strip from the plane of emergence, and a connection portion joining the two curved portions to one another and having at least one loop situated outside the plane of emergence. The fact that the loop of the strip inside the facing is offset outside the plane of emergence allows this strip to penetrate into the thickness of the facing while remaining oriented in this plane down to a certain depth. This ensures good guiding of the strips as they emerge from the facing and avoids inappropriate stressing of the cast material (generally concrete). This permits good positioning and effective anchoring of the reinforcement strip while ensuring that it does not follow excessively sharp curves and avoiding to subject it to high contraction forces. The rectilinear portions of said path preferably each extend in the plane of emergence by at least half the thickness of the facing. The reinforcement strip typically has a width at most equal to half the thickness of the facing. In one embodiment of the structure, the facing has, in the anchoring region, a protective sheath receiving the reinforcement strip along said path. This sheath separates the strip from the cast material so as to protect the reinforcement against premature damage. In particular, if the reinforcement is obtained using polyester fibres, it is known that these poorly tolerate alkaline environments such as those found in concrete. The aforementioned sheath thus complements the protection conferred by the plastic coating on the polyester fibres of the strip. A second aspect of the invention concerns a facing element for a stabilized soil structure, comprising a body of cast material inside which a path is formed for a reinforcement strip betv?een two points of emergence situated on a rear face of the body. The path includes two rectilinear portions respectively adjacent to the two points of emergence and each arranged to position the strip in a common plane of emergence perpendicular to said rear face, two curved portions respectively continuing the two rectilinear portions and arranged to deviate the strip from the plane of emergence, and a connection portion joining the two curved portions to one another and having at least one loop situated outside the plane of emergence. The strip can be put in place in the path at the time the material of the body is cast, with or without the above-mentioned protective sheath. Various configurations are possible for the path defined for the strip within the facing element. In some embodiments, the two curved portions of the path direct the strip towards a common side of the plane of emergence. In this case, a first possibility is for the path to be formed so as to receive the strip in the two rectilinear portions with the same face of the strip oriented towards this side of the plane of emergence. The path is thus formed so that said face of the strip is placed either on the outer side or on the inner side of the loop situated outside the plane of emergence. A second possibility is for the path to be formed so as to receive the strip in one of the two rectilinear portions with one face of the strip oriented towards said side of the plane of emergence and in the other of the two rectilinear portions with said face of the strip oriented away from said side; of the plane of emergence. In another embodiment, the two curved portions of the path respectively direct the strip towards two opposite sides of the plane of emergence, and the connection portion of the path has two loops which respectively continue the two cux^ved portions of the path, and a part which crosses the plane of emergence and joins the two loops to one another. Other features and advantages of the present invention will become apparent from the description below of some non-limiting illustrative embodiments, with reference being made to the attached drawings, in which: Figure 1 is a schematic view in lateral section of a stabilized soil structure according to the invention in the process of being built; Figure 2 is a cross-sectional view of a facing element according to the invention; Figures 3 to 6 are perspective views of paths that reinforcement strips may follow within facing elements according to the invention; and Figure 7 is a rear view of another facing element according to the invention. Figure. 1 illustrates the application of the invention to the building of a stabilized soil retaining wall. A compacted fill 1, in which reinforcements 2 are distributed, is delimited on the front side of the structure by a facing 3 formed by juxtaposing prefabricated elements 4 in the form of panels, and on the rear side by the soil 5 against which the retaining wall is erected. The reinforcements 2 comprise synthetic reinforcing members in the form of flexible strips extending in horizontal planes behind the facing 3. These may in particular be reinforcement strips based on polyester fibres encased in polyethylene. The reinforcement strips 2 are attached to the prefabricated elements 4 joined together to form the facing 3. These elements 4 are typically made of reinforced concrete. In the example shown, they are in the form of panels. They could also have other forms, in particular the form of blocks. When the concrete of such an element 4 is cast, one or more reinforcement strips 2 are installed in the mould, along a path described below, to provide the strip-element anchorage. After the concrete has set, each strip has two sections which emerge from the element and are to be installed in the fill material. For erecting the structure, the procedure may be as follows: a) Placing some of the facing elements 4 so as then to be able to introduce fill material over a certain depth. In a known manner, the erection and positioning of the facing elements may be made easier by assembly members placed between them. The strips 2 are so positioned on the facing elements 4 that some of them are located at the same horizontal level when the facing is erected. b) Introducing fill material and compacting it progressively until the next specified level for placement of the reinforcement strips 2 is reached. c) Laying the reinforcement strips 2 on the fill at this level. d) Introducing fill material over the reinforcement strips 2 which have just been installed. This fill material is compacted as it is introduced. e) Repeating steps b) to d) if several levels of strips are provided per series of facing elements 4. f) Repeating steps a) to e) until the upper level of the fill is reached. During introduction and compacting of the fill material, the reinforcement strips 2 already placed at the lower levels experience tensioning. This tensioning results from the friction between the strips and the filled material and ensures the reinforcement of the structure. So that the tension is established under good conditions, it is advisable that the strips of one level emerge from their facing elements so that they are all correctly aligned with this level. It is also advisable that they are oriented horizontally as they emerge from the facing, so as to ensure that they do not twist in the filled material. At their points of emergence 6 from a facing element, the two sections of a strip 2 are in a common plane of emergence P (perpendicular to the plane of Figure 2) . When the facing 3 is erected, the elements 4 are so oriented that this plane of emergence is horizontal. Figure 2 shows a facing element that can be used in some embodiments of the invention. As is customary, this element 4 is made of cast concrete. A reinforcement strip 2 is placed in the mould at the moment of casting the concrete therein and is maintained in place until the concrete has set. It can be guided with the aid of the reinforcing bars (not shown) of the concrete, optionally complemented by deviator rods or members fixed to these bars, so that the strip follows the desired path in the anchoring zone. This path is defined inside the element 4 between the two points of emergence 6 of the two portions of the strip on the rear face 7 of the element (face adjacent to the fill) . The path corresponding to the element in Figure 2 is illustrated by Figure 3. It has two rectilinear portions 8 extending perpendicular to the rear face 7 of the element starting from the points of emergence 6. In each rectilinear portion 8, the strip remains in its plane of emergence P. The rectilinear portions 8 extend by at least half the thickness of the body of the element 4, measured perpendicular to its rear face 7. This avoids undesired stressing of the concrete near the rear face 7. Each rectilinear portion 8 of the path of the strip is continued by a respective curved portion 9 where the strip deviates from the plane of emergence P. Beyond this curved portion 9, the strip 2 extends along the front face of the element, set back slightly from this front face so as not to be noticeable at the surface of the structure. The two curved portions 9 are joined to one another by a connection portion which has a loop 10 situated outside the plane of emergence P. In the example in Figures 2 and 3, the strip is directed towards the same side PI of the plane of emergence P in the two curved portions 9 of its path inside the facing element 4. This path is formed in such a way (i) that, in the two rectilinear portions 8, the strip has the same face oriented towards the side PI of the plane of emergence, and (ii) that this face of the strip is placed on the outer side of the loop 10. Consequently, at the middle of the loop 10, the strip is positioned practically perpendicular to the rear face 7 of the element. In the alternative embodiment illustrated in Figure 4, the loop 10' is oriented in the opposite direction, i.e. the face of the strip oriented towards the side PI of the plane of emergence is placed on the inner side of the loop 10'. In the alternative embodiment illustrated in Figure 5, the strip follows one of the two rectilinear portions 8 of its path with one of its two faces oriented towards the side PI of the plane of emergence P and with the other one of the two rectilinear portions 8 having said face oriented towards the side P2 of the plane of emergence opposite from side PI. Other configurations are also possible for the path followed by the reinforcement strip inside a facing element. Figure 6 shows an example in which the connection portion joining the two curved portions 19 to one another includes two loops 20 on each side of the plane P. In this example, the two curved portions 19 of the path respectively direct the strip towards the opposite two sides PI, P2 of the plane of emergence P. The connection portion has a part 21 which crosses the plane P and joins the two loops 2 0 to one another. In order to easily follow a path such as the ones illustrated in Figures 3 to 6, it is preferable that the width of the strip 2 is less than or at most equal to half the thickness of the facing element 4. This thickness is typically between 14 and 16 cm. It will be possible to use strips having a width of about 45 mm. When the reinforcement strip has components (for example polyester fibres) sensitive to alkaline environments, it may be advantageous to place a protective sheath made of plastic between this strip and the concrete facing. This sheath ensures that the alkalinity of the concrete does not propagate down to the sensitive component. The f lexibles sheath receives the strip before being placed together with it in the mould. It is thus surrounded by the poured concrete and it receives the reinforcement strip cilong its path in order to separate it from the concrete. It is conceivable that the reinforcement strip is not yet fitted in its sheath 15 at the time the element is produced. It is thus convenient to use a rigid sheath that has been shaped beforehand to the desired path. Figure 7 shows the rear face of a facing element 4 formed in this way and capable of receiving two reinforcement strips at vertically spaced levels. The sheaths 15 define the paths inside the element 4 between the points of emergence 6. They can be pre- formed rigid sheaths, for example according to one of the shapes illustrated in Figures 3 to 6. A configuration according to Figure 7 requires an operation of threading the strips along their paths. However, it has the advantage of making it possible to choose the strip length independently of the production of the facing element. Generally speaking, the proposed method of connection, between the facing of a stabilized soil structure and at least some of its reinforcement strips, is compatible with a large number of structural configurations, strip lengths, strip positioning densities, etc. WE CLAIM : 1. A stabilized soil structure, comprising a fill (1) , reinforcement strips (2) extending through a reinforced zone of the fill situated behind a front face of the structure, and a facing (3) placed along said front face, the reinforcement strips being anchored to the facing in respective anchoring regions, wherein the facing incorporates, in at least one anchoring region, a path formed for a reinforcement strip between two points of emergence (6) situated on a rear face of the facing (7) adjacent to the fill, characterized in that the path includes two rectilinear portions (8) respectively adjacent to the two points of emergence and each arranged to position the strip in a common plane of emergence (P) perpendicular to said rear face, two curved portions (9; 19) respectively continuing the two rectilinear portions and arranged to deviate the strip from the plane of emergence, and a connection portion joining the two curved portions to one another and having at least one loop (10; 10'; 10"; 20) situated outside the plane of emergence. 2. The structure of Claim 1, wherein the facing (3) is made from elements (4) in the form of panels, and wherein the rectilinear portions (8) of said path each extend in the plane of emergence (P) by at least half the thickness of a panel-shaped facing element. 3. The structure of Claim 1 or 2, wherein the reinforcement strip (2) has a width at most equal to half the thickness of the facing (3). 4. The structure of any one of the preceding claims, wherein the facing (3) has, in the anchoring region, a protective sheath (15) receiving the reinforcement strip (2) along said path. 5. A facing element for a stabilized soil structure, comprising a body (4) of cast material inside which a path is formed for a reinforcement strip (2) between two points of emergence (6) situated on a rear face of the body, characterized in that the path includes two rectilinear portions (8) respectively adjacent to the two points of emergence and each arranged to position the strip in a common plane of emergence (P) perpendicular to said rear face, two curved portions (9; 19) respectively continuing the two rectilinear portions and arranged to deviate the strip from the plane of emergence, and a connection portion joining the two curved portions to one another and having at least one loop (10; 10'; 10"; 20) situated outside the plane of emergence. 6. The facing element of Claim 5, wherein the body (4) is in the form of a panel, and wherein the rectilinear portions (8) of said path each extend in the plane of emergence (P) by at least half a thickness of the body, measured perpendicular to the rear face (7). 7. The facing element of Claim 5 or 6, wherein the body (4) has, perpendicular to the rear face (7) , a thickness at least equal to twice the width of the reinforcement strip (2). 8. The facing element of any one of Claims 5 to 7, further comprising a protective sheath (15) surrounded by the cast material of the body (4) , in order to receive the reinforcement strip (2) along said path and separate the strip from the cast material. 9. The facing element of Claim 8, wherein the strip (2) is not installed in the sheath (15) at the time the element is produced. 10. The facing element of any one of Claims 5 to 8, wherein the strip (2) is placed in said path when the material of the body (4) is cast. 11. The facing element of any one of Claims 5 to 10, wherein the two curved portions (9) of the path direct the strip (2) towards a common side (PI) of the plane of emergence (P) , and wherein said path is so formed that the strip is received in the two rectilinear portions (8) with a common face of the strip oriented towards said side of the plane of emergence. 12. The facing element of Claim 11, wherein said path is so formed that said face of the strip is placed on an outer side of the loop (10) situated outside the plane of emergence (P). 13. The facing element of Claim 11, wherein said path is so formed that said face of the strip is placed on an inner side of the loop (10') situated outside the plane of emergence (P). 14. The facing element of any one of Claims 5 to 10, wherein the two curved portions (9) of the path direct the strip (2) towards a common side (PI) of the plane of emergence (P) , and wherein said path is so formed that the strip is received in one of the two rectilinear portions (8) with one face of the strip oriented towards said side of the plane of emergence and in the other one of the two rectilinear portions with said face of the strip oriented away from said side of the plane of emergence. 15. The facing element of any one of Claims 5 to 10, wherein the two curved portions (19) of the path respectively direct the strip (2) towards two opposite sides (PI, P2) of the plane of emergence (P) , and wherein said connection portion has two loops (20) respectively continuing the two curved portions of the path, and a part (21) crossing the plane of emergence and joining the two loops to one another. The facing element for a stabilized soil structure comprises a body (4) of cast material inside which a path is formed for a reinforcement strip (2) between two points of emergence (6) situated on a rear face (7) of the element. This path includes two rectilinear portions (8) which are respectively adjacent to the two points of emergence and are each arranged so as to position the strip in the same plane of emergence perpendicular to the rear face, two curved portions (9) which respectively continue the two rectilinear portions and are arranged so as to deviate the strip from the plane of emergence, and a connection portion which joins the two curved portions to one another and has at least one loop (10) situated outside the plane of emergence.

Full Text

The present invention relates to the construction of
stabilized soil or reinforced earth structures. This
building technique is commonly used to produce
structures such as retaining walls, bridge abutments,
etc.
A stabilized soil structure combines a compacted fill,
a facing, and reinforcements usually connected to the
facing. The reinforcements are placed in the soil with
a density dependent on the stresses that might be
exerted on the structure, the thrust forces of the soil
being reacted by the soil-reinforcements friction.
The invention more particularly concerns the case where
the reinforcements are in the form of strips of
synthetic material, for example based on polyester
fibres.
The facing is most often made up of prefabricated
concrete elements, in the form of slabs or blocks,
juxtaposed to cover the front face of the structure.
There may be horizontal steps on this front face
between different levels of the facing, when the
structure has one or more terraces.
The reinforcements placed in the fill are usually
secured to the facing by mechanical connecting members
that may take various forms. Once the structure is
complete, the reinforcements distributed through the
fill transmit high loads, in some cases of up to
several tonnes. Their connection to the facing needs to
be robust in order to maintain the cohesion of the
whole.
The connecting members exhibit risks of degradation.

They are often sensitive to corrosion due to moisture
or to chemical agents which are present in or which
have infiltrated into the fill. The connecting members
are sometimes made on the basis of resins or composite
materials so that they corrode less readily. However,
their cost is then increased, and it is difficult to
give them good mechanical properties. It is therefore
desirable to be able to dispense with connecting
members between the facing element and the
reinforcements of the structure.
In some systems, the facing elements are configured in
such a way as to present at least one passage intended
to receive a reinforcement strip.
In US-A-5 839 855, the passage is in the shape of a C
within the thickness of the facing element in the form
of a panel. When the strip is put in place, its two
sections emerging from the facing element are located
in two parallel horizontal planes offset in the
vertical direction. This condition of emergence of the
strips from the panel is not ideal because it makes it
necessary . to increase the number of filling and
compacting operations, which complicates and prolongs
the implementation of the work. This does not easily
permit homogeneous tensioning of the strips, because
the strip is not retained by the panel when its lower
portion is covered with fill.
For these reasons, it is generally desirable for the
strips to emerge from the facing element in the same
horizontal plane.
In addition, the C-shaped path of the reinforcement
strips is not optimal in terms of the robustness of the
anchoring when stressed. The curve of the path near the
point of emergence of the strip weakens its anchoring
to the element because it causes working in tension of
a small thickness of concrete, which, is not a good way
of Stressing this material.
A similar problem arises with a facing element of the
type described in FR-A-2 812 893. This element also has
a pre-formed path in the shape of a C. In addition,
this C-shaped path is arranged so that each portion of
the reinforcement strip emerges from the element
oriented in a vertical plane. This is unsatisfactory
because the strip placed on the ground positions itself
naturally in a horizontal plane, so that each portion
of the strip in the fill twists one quarter of a turn.
Such twisting is unfavourable in terms of the
mechanical behaviour of the reinforcement.
It is an object of the present invention to propose a
novel method of anchoring reinforcement strips to a
facing of a stabilized soil structure, making it
possible to reduce the incidence of the problems set
out above.
The invention thus proposes a stabilized soil
structure, comprising a fill, reinforcement strips
extending through a reinforced zone of the fill
situated behind a front face of the structure, and a
facing placed along said front face, the reinforcement
strips being anchored to the facing in respective
anchoring regions. In at least one anchoring region,
the facing incorporates a path formed for a
reinforcement strip between two points of emergence
situated on a rear face of the facing adjacent to the
fill. This path includes two rectilinear portions
respectively adjacent to the two points of emergence
and each arranged to position the strip in a common
plane of emergence perpendicular to said rear face, two
curved portions respectively continuing the two
rectilinear portions and arranged to deviate the strip
from the plane of emergence, and a connection portion
joining the two curved portions to one another and
having at least one loop situated outside the plane of
emergence.
The fact that the loop of the strip inside the facing
is offset outside the plane of emergence allows this
strip to penetrate into the thickness of the facing
while remaining oriented in this plane down to a
certain depth. This ensures good guiding of the strips
as they emerge from the facing and avoids inappropriate
stressing of the cast material (generally concrete).
This permits good positioning and effective anchoring
of the reinforcement strip while ensuring that it does
not follow excessively sharp curves and avoiding to
subject it to high contraction forces.
The rectilinear portions of said path preferably each
extend in the plane of emergence by at least half the
thickness of the facing. The reinforcement strip
typically has a width at most equal to half the
thickness of the facing.
In one embodiment of the structure, the facing has, in
the anchoring region, a protective sheath receiving the
reinforcement strip along said path. This sheath
separates the strip from the cast material so as to
protect the reinforcement against premature damage. In
particular, if the reinforcement is obtained using
polyester fibres, it is known that these poorly
tolerate alkaline environments such as those found in
concrete. The aforementioned sheath thus complements
the protection conferred by the plastic coating on the
polyester fibres of the strip.
A second aspect of the invention concerns a facing
element for a stabilized soil structure, comprising a
body of cast material inside which a path is formed for
a reinforcement strip betv?een two points of emergence
situated on a rear face of the body. The path includes
two rectilinear portions respectively adjacent to the
two points of emergence and each arranged to position
the strip in a common plane of emergence perpendicular
to said rear face, two curved portions respectively
continuing the two rectilinear portions and arranged to
deviate the strip from the plane of emergence, and a
connection portion joining the two curved portions to
one another and having at least one loop situated
outside the plane of emergence.
The strip can be put in place in the path at the time
the material of the body is cast, with or without the
above-mentioned protective sheath.
Various configurations are possible for the path
defined for the strip within the facing element. In
some embodiments, the two curved portions of the path
direct the strip towards a common side of the plane of
emergence. In this case, a first possibility is for the
path to be formed so as to receive the strip in the two
rectilinear portions with the same face of the strip
oriented towards this side of the plane of emergence.
The path is thus formed so that said face of the strip
is placed either on the outer side or on the inner side
of the loop situated outside the plane of emergence. A
second possibility is for the path to be formed so as
to receive the strip in one of the two rectilinear
portions with one face of the strip oriented towards
said side of the plane of emergence and in the other of
the two rectilinear portions with said face of the
strip oriented away from said side; of the plane of
emergence.
In another embodiment, the two curved portions of the
path respectively direct the strip towards two opposite
sides of the plane of emergence, and the connection
portion of the path has two loops which respectively
continue the two cux^ved portions of the path, and a
part which crosses the plane of emergence and joins the
two loops to one another.

Other features and advantages of the present invention
will become apparent from the description below of some
non-limiting illustrative embodiments, with reference
being made to the attached drawings, in which:
Figure 1 is a schematic view in lateral section of
a stabilized soil structure according to the
invention in the process of being built;
Figure 2 is a cross-sectional view of a facing
element according to the invention;
Figures 3 to 6 are perspective views of paths that
reinforcement strips may follow within facing
elements according to the invention; and
Figure 7 is a rear view of another facing element
according to the invention.
Figure. 1 illustrates the application of the invention
to the building of a stabilized soil retaining wall. A
compacted fill 1, in which reinforcements 2 are
distributed, is delimited on the front side of the
structure by a facing 3 formed by juxtaposing
prefabricated elements 4 in the form of panels, and on
the rear side by the soil 5 against which the retaining
wall is erected.
The reinforcements 2 comprise synthetic reinforcing
members in the form of flexible strips extending in
horizontal planes behind the facing 3. These may in
particular be reinforcement strips based on polyester
fibres encased in polyethylene.
The reinforcement strips 2 are attached to the
prefabricated elements 4 joined together to form the
facing 3. These elements 4 are typically made of
reinforced concrete. In the example shown, they are in
the form of panels. They could also have other forms,
in particular the form of blocks. When the concrete of
such an element 4 is cast, one or more reinforcement

strips 2 are installed in the mould, along a path
described below, to provide the strip-element
anchorage. After the concrete has set, each strip has
two sections which emerge from the element and are to
be installed in the fill material.
For erecting the structure, the procedure may be as
follows:
a) Placing some of the facing elements 4 so as then
to be able to introduce fill material over a
certain depth. In a known manner, the erection and
positioning of the facing elements may be made
easier by assembly members placed between them.
The strips 2 are so positioned on the facing
elements 4 that some of them are located at the
same horizontal level when the facing is erected.
b) Introducing fill material and compacting it
progressively until the next specified level for
placement of the reinforcement strips 2 is
reached.
c) Laying the reinforcement strips 2 on the fill at
this level.
d) Introducing fill material over the reinforcement
strips 2 which have just been installed. This fill
material is compacted as it is introduced.
e) Repeating steps b) to d) if several levels of
strips are provided per series of facing elements
4.
f) Repeating steps a) to e) until the upper level of
the fill is reached.
During introduction and compacting of the fill
material, the reinforcement strips 2 already placed at
the lower levels experience tensioning. This tensioning
results from the friction between the strips and the
filled material and ensures the reinforcement of the
structure. So that the tension is established under
good conditions, it is advisable that the strips of one
level emerge from their facing elements so that they
are all correctly aligned with this level. It is also
advisable that they are oriented horizontally as they
emerge from the facing, so as to ensure that they do
not twist in the filled material.
At their points of emergence 6 from a facing element,
the two sections of a strip 2 are in a common plane of
emergence P (perpendicular to the plane of Figure 2) .
When the facing 3 is erected, the elements 4 are so
oriented that this plane of emergence is horizontal.
Figure 2 shows a facing element that can be used in
some embodiments of the invention. As is customary,
this element 4 is made of cast concrete. A
reinforcement strip 2 is placed in the mould at the
moment of casting the concrete therein and is
maintained in place until the concrete has set. It can
be guided with the aid of the reinforcing bars (not
shown) of the concrete, optionally complemented by
deviator rods or members fixed to these bars, so that
the strip follows the desired path in the anchoring
zone. This path is defined inside the element 4 between
the two points of emergence 6 of the two portions of
the strip on the rear face 7 of the element (face
adjacent to the fill) .
The path corresponding to the element in Figure 2 is
illustrated by Figure 3. It has two rectilinear
portions 8 extending perpendicular to the rear face 7
of the element starting from the points of emergence 6.
In each rectilinear portion 8, the strip remains in its
plane of emergence P. The rectilinear portions 8 extend
by at least half the thickness of the body of the
element 4, measured perpendicular to its rear face 7.
This avoids undesired stressing of the concrete near
the rear face 7.
Each rectilinear portion 8 of the path of the strip is
continued by a respective curved portion 9 where the
strip deviates from the plane of emergence P. Beyond
this curved portion 9, the strip 2 extends along the
front face of the element, set back slightly from this
front face so as not to be noticeable at the surface of
the structure.
The two curved portions 9 are joined to one another by
a connection portion which has a loop 10 situated
outside the plane of emergence P.
In the example in Figures 2 and 3, the strip is
directed towards the same side PI of the plane of
emergence P in the two curved portions 9 of its path
inside the facing element 4. This path is formed in
such a way (i) that, in the two rectilinear portions 8,
the strip has the same face oriented towards the side
PI of the plane of emergence, and (ii) that this face
of the strip is placed on the outer side of the loop
10. Consequently, at the middle of the loop 10, the
strip is positioned practically perpendicular to the
rear face 7 of the element.
In the alternative embodiment illustrated in Figure 4,
the loop 10' is oriented in the opposite direction,
i.e. the face of the strip oriented towards the side PI
of the plane of emergence is placed on the inner side
of the loop 10'.
In the alternative embodiment illustrated in Figure 5,
the strip follows one of the two rectilinear portions 8
of its path with one of its two faces oriented towards
the side PI of the plane of emergence P and with the
other one of the two rectilinear portions 8 having said
face oriented towards the side P2 of the plane of
emergence opposite from side PI.
Other configurations are also possible for the path

followed by the reinforcement strip inside a facing
element. Figure 6 shows an example in which the
connection portion joining the two curved portions 19
to one another includes two loops 20 on each side of
the plane P. In this example, the two curved portions
19 of the path respectively direct the strip towards
the opposite two sides PI, P2 of the plane of emergence
P. The connection portion has a part 21 which crosses
the plane P and joins the two loops 2 0 to one another.
In order to easily follow a path such as the ones
illustrated in Figures 3 to 6, it is preferable that
the width of the strip 2 is less than or at most equal
to half the thickness of the facing element 4. This
thickness is typically between 14 and 16 cm. It will be
possible to use strips having a width of about 45 mm.
When the reinforcement strip has components (for
example polyester fibres) sensitive to alkaline
environments, it may be advantageous to place a
protective sheath made of plastic between this strip
and the concrete facing. This sheath ensures that the
alkalinity of the concrete does not propagate down to
the sensitive component. The f lexibles sheath receives
the strip before being placed together with it in the
mould. It is thus surrounded by the poured concrete and
it receives the reinforcement strip cilong its path in
order to separate it from the concrete.
It is conceivable that the reinforcement strip is not
yet fitted in its sheath 15 at the time the element is
produced. It is thus convenient to use a rigid sheath
that has been shaped beforehand to the desired path.
Figure 7 shows the rear face of a facing element 4
formed in this way and capable of receiving two
reinforcement strips at vertically spaced levels. The
sheaths 15 define the paths inside the element 4
between the points of emergence 6. They can be pre-
formed rigid sheaths, for example according to one of

the shapes illustrated in Figures 3 to 6.
A configuration according to Figure 7 requires an
operation of threading the strips along their paths.
However, it has the advantage of making it possible to
choose the strip length independently of the production
of the facing element.
Generally speaking, the proposed method of connection,
between the facing of a stabilized soil structure and
at least some of its reinforcement strips, is
compatible with a large number of structural
configurations, strip lengths, strip positioning
densities, etc.

WE CLAIM :
1. A stabilized soil structure, comprising a fill
(1) , reinforcement strips (2) extending through a
reinforced zone of the fill situated behind a
front face of the structure, and a facing (3)
placed along said front face, the reinforcement
strips being anchored to the facing in respective
anchoring regions, wherein the facing
incorporates, in at least one anchoring region, a
path formed for a reinforcement strip between two
points of emergence (6) situated on a rear face of
the facing (7) adjacent to the fill, characterized
in that the path includes two rectilinear portions
(8) respectively adjacent to the two points of
emergence and each arranged to position the strip
in a common plane of emergence (P) perpendicular
to said rear face, two curved portions (9; 19)
respectively continuing the two rectilinear
portions and arranged to deviate the strip from
the plane of emergence, and a connection portion
joining the two curved portions to one another and
having at least one loop (10; 10'; 10"; 20)
situated outside the plane of emergence.
2. The structure of Claim 1, wherein the facing (3)
is made from elements (4) in the form of panels,
and wherein the rectilinear portions (8) of said
path each extend in the plane of emergence (P) by
at least half the thickness of a panel-shaped
facing element.
3. The structure of Claim 1 or 2, wherein the
reinforcement strip (2) has a width at most equal
to half the thickness of the facing (3).
4. The structure of any one of the preceding claims,
wherein the facing (3) has, in the anchoring
region, a protective sheath (15) receiving the

reinforcement strip (2) along said path.
5. A facing element for a stabilized soil structure,
comprising a body (4) of cast material inside
which a path is formed for a reinforcement strip
(2) between two points of emergence (6) situated
on a rear face of the body, characterized in that
the path includes two rectilinear portions (8)
respectively adjacent to the two points of
emergence and each arranged to position the strip
in a common plane of emergence (P) perpendicular
to said rear face, two curved portions (9; 19)
respectively continuing the two rectilinear
portions and arranged to deviate the strip from
the plane of emergence, and a connection portion
joining the two curved portions to one another and
having at least one loop (10; 10'; 10"; 20)
situated outside the plane of emergence.
6. The facing element of Claim 5, wherein the body
(4) is in the form of a panel, and wherein the
rectilinear portions (8) of said path each extend
in the plane of emergence (P) by at least half a
thickness of the body, measured perpendicular to
the rear face (7).
7. The facing element of Claim 5 or 6, wherein the
body (4) has, perpendicular to the rear face (7) ,
a thickness at least equal to twice the width of
the reinforcement strip (2).
8. The facing element of any one of Claims 5 to 7,
further comprising a protective sheath (15)
surrounded by the cast material of the body (4) ,
in order to receive the reinforcement strip (2)
along said path and separate the strip from the
cast material.
9. The facing element of Claim 8, wherein the strip

(2) is not installed in the sheath (15) at the
time the element is produced.
10. The facing element of any one of Claims 5 to 8,
wherein the strip (2) is placed in said path when
the material of the body (4) is cast.
11. The facing element of any one of Claims 5 to 10,
wherein the two curved portions (9) of the path
direct the strip (2) towards a common side (PI) of
the plane of emergence (P) , and wherein said path
is so formed that the strip is received in the two
rectilinear portions (8) with a common face of the
strip oriented towards said side of the plane of
emergence.
12. The facing element of Claim 11, wherein said path
is so formed that said face of the strip is placed
on an outer side of the loop (10) situated outside
the plane of emergence (P).
13. The facing element of Claim 11, wherein said path
is so formed that said face of the strip is placed
on an inner side of the loop (10') situated
outside the plane of emergence (P).
14. The facing element of any one of Claims 5 to 10,
wherein the two curved portions (9) of the path
direct the strip (2) towards a common side (PI) of
the plane of emergence (P) , and wherein said path
is so formed that the strip is received in one of
the two rectilinear portions (8) with one face of
the strip oriented towards said side of the plane
of emergence and in the other one of the two
rectilinear portions with said face of the strip
oriented away from said side of the plane of
emergence.
15. The facing element of any one of Claims 5 to 10,

wherein the two curved portions (19) of the path
respectively direct the strip (2) towards two
opposite sides (PI, P2) of the plane of emergence
(P) , and wherein said connection portion has two
loops (20) respectively continuing the two curved
portions of the path, and a part (21) crossing the
plane of emergence and joining the two loops to
one another.

The facing element for a stabilized soil structure
comprises a body (4) of cast material inside which a
path is formed for a reinforcement strip (2) between
two points of emergence (6) situated on a rear face (7)
of the element. This path includes two rectilinear
portions (8) which are respectively adjacent to the two
points of emergence and are each arranged so as to
position the strip in the same plane of emergence
perpendicular to the rear face, two curved portions (9)
which respectively continue the two rectilinear
portions and are arranged so as to deviate the strip
from the plane of emergence, and a connection portion
which joins the two curved portions to one another and
has at least one loop (10) situated outside the plane
of emergence.

STABILIZED SOIL STRUCTURE AND FACING ELEMENTS FOR ITS CONSTRUCTION

Documents:

Inventors:

PCT Conventions: