EP2369058B1 - Method of compacting soils, application of this method, and device for carrying out the method - Google Patents

Description

The present invention relates to methods for compacting soils. It aims to increase the density of materials in depth, so as to improve the geotechnical characteristics of the layer. It concerns both new construction work such as the construction of foundation layers for road, airport and railway works, as well as maintenance and repair work carried out below a railway line without having to proceed with the construction work. remove rails and sleepers.

It is known that the compaction of soils or granular materials spread in layer is, in the usual way, carried out by means of compactors circulating on the upper part of the layer. The compactors then apply to the upper part of the layer a force which will induce a pressure within the material and cause the irreversible deformations of compaction. The stresses induced within the material decrease with the depth and consequently the density obtained by compaction is not homogeneous over the entire thickness of the layer. As a result, the density distribution within the compacted material also decreases with the depth.

It is known, in the state of the art, to choose the compactors and to define their operating modes for the various cases of soils and materials and of layer thickness in order to obtain a satisfactory bottom layer density, provided that the thickness of the layer is not too important.

So for clay or loamy soils treated with a hydraulic binder (silts, fine sands more or less clayey in particular) the maximum thickness of the compacted layer is in practice limited to 30 or 35 centimeters, because the use of the vibrating machines the most heavy would cause a surface lamination detrimental to the long-term performance of the structure.

The methods of study and calculation of structures in treated soil take into account - of course - the current state of technology. Thus, it is well known that the density of the layer base to be required must be 96% of the normal proctor density (reference used in road geotechnics). It should be known that if a density of the bottom layer equal to 100% of the normal proctor optimum could be guaranteed, the dimensioning of the layer, with an identical lifetime, could be reduced by around 20%. .

It is also known that if one could increase the thickness of a foundation layer in 5 cm treated soil, with a density of the bottom layer equal to 100% of the optimum proctor, its life would be multiplied at least 10

On the other hand, the difficulties of controlling this fundamental parameter of the compactness of the layer bottom produced, in particular its resistance to fatigue, leads to take into account high safety factors.

It therefore appears that the possibility of compaction of the lower part of the layer, and, more generally, compaction beyond the physical limits imposed by compaction from the surface, would be of essential interest. It would then be possible to obtain high compacities at the bottom of the layer and to make thicker layers of pavement in reduced numbers.

It is also known that it is not possible to compact the soil under an existing structure.

Thus in the case of railways laid on a ballast distribution layer, maintenance work, without having to remove the tracks allow the repackaging or substitution of the ballast layer, but without being able to adjust and compact its seat.

The ballast is therefore implemented on a deformed support, low lift where rainwater stagnates and accelerates the damage. After two or three such interventions, it is necessary to rebuild or construct a foundation layer under the ballast layer. This work requires the removal of lanes and the interruption of traffic over a long period.

It is known from the French patent application N ° 2,882,377, filed February 22, 2005 in the name of FIBAC SA, inventor JOLY Claude, to deeply treat dry soils by burying in the soil a treatment liquid more or less loaded with lime. For this purpose, hollow triangular teeth are fixed in the ground, at an adequate depth, fixed on supports and distributed in staggered rows. These supports are fixed on a chassis, itself towed by a vehicle. This allows to inject at this depth, from the back of the teeth, the liquid which is thus distributed over the entire width of this device. This document describes a process according to the preamble of claim 1.

However this device does not allow to compact the soil under the teeth, since these are in principle horizontal, and even, if one refers to the Figure 3 , slightly inclined upwards going from front to rear, the tensile force can only increase this inclination.

The document FR 789415 describes a device according to the preamble of claim 2.

To solve these problems, the invention proposes a method according to claim 1 and a device according to claim 6 which makes it possible to compact the soil, in its thickness, below an overlap or below an existing structure such as a track. railway.

For this, in a first step is inserted into the soil, at a specific depth (H), a soil treatment device, and in a second step is advanced this device by maintaining it at the determined depth; said treatment device being mainly characterized in that it is arranged to continuously compact the soil beneath it, which allows to continuously compact the soil to a depth where compaction processes from above the soil become ineffective.

According to another characteristic, a tool for implementing the invention comprises a wedge-shaped tooth whose leading edge is directed forward to take off the upper layers of the ground; this tooth being fixed to a frame by means of an intermediate piece serving as a common support for the tooth and a blade which is also fixed to the rear of the tooth and which has a curved shape whose concavity is directed towards the top, whose front is at lower level of the soil taken off and the lowest part of which is at the compaction level desired for a single pass of the device.

According to another characteristic, the blade is thick enough not to bend under compaction efforts and its profile has a curved shape, corresponding to the desired average eccentricity.

According to another feature, the blade or spring itself, or is fixed at its front end by a transverse hinge and is held in compression by a spring.

According to another characteristic, the tool comprises a wedge-shaped tooth whose leading edge is directed forward to take off the upper layers of the ground and whose lower part is inclined downwards to perform a first compaction to an intermediate level; this tooth is fixed on a frame with the aid of an intermediate piece which also supports at the rear of the tooth a compaction roller making it possible to carry out a second compaction to obtain the desired level, this roll being or smooth, or streaked, or supporting sheep's feet.

According to another characteristic, the tool comprises a simple wear blade inclined from front to back to take off the upper layers of the ground; this blade is fixed on a frame by an intermediate piece serving as a common support for the blade and a set of rollers fixed on a second intermediate piece itself attached to the first piece; these rollers are arranged substantially next to each other parallel to the surface of the ground and perpendicular to the axis of advance of the device; the first of these rollers is further arranged slightly lower than the wear tip of the wear blade, and the other rollers are slightly offset in depth so that the latter is at the desired level for compaction depth h.

According to another characteristic, the tool comprises an intermediate piece comprising a known support, which comprises a longitudinal hole for receiving tools for unpacking a soil, such as a chisel or a tooth, and said support is completed on its part. lower by one piece flat fixed on the lower end of said support; said flat part comprises at its lower part a first vertical fin having a hole in front and on its rear three holes spaced in height, this assembly forming said intermediate piece; and the device also comprises a compaction member which comprises in turn a curved blade whose concavity is directed upwards, this blade reproducing the compaction curve under the repeated effect of the passage of a compactor acting from the surface ; said blade comprises a second vertical fin fixed on the upper part of the blade and is itself provided with a hole at the front and on its rear three holes staggered in height; these two fins are positioned against each other by making the two front holes coincide and by driving in these two holes fixing means which make it possible to turn the second fin on the surface of the first fin; the rear holes on each of these fins are staggered so that, when rotating the second fin on the first, only one of the rear holes thereof corresponds to a single back hole of the first fin; which thus makes it possible to obtain three positions of the fins relative to one another and thus three different eccentricities for said blade.

According to another characteristic, a tractor vehicle is used to drive a rigid frame provided with means for maintaining, at a determined depth H and adjustable below the ground level, a set of tools as defined above.

According to another characteristic, said frame is subjected to a vibratory movement, it is decoupling, from the point of view of vibration, the frame of the towing vehicle by an elastic attachment.

The device according to the invention comprises a rotor provided with at least one star comprising a set of spokes, is fixed at the end of at least one of these rays a wedge-shaped tool as defined above; this rotor is rotated and is arranged under a protective bell; and the whole is animated with a translational movement horizontal and perpendicular to the axis of the rotor for compact a strip of land slightly wider than the width of the bell.

According to another characteristic, the direction of rotation of the rotor is the same as the direction of advancement of the assembly.

According to another characteristic, the rotor / bell assembly is fixed on a carrier vehicle, either at the front, in the middle or at the rear of said vehicle.

According to another characteristic, the invention is implemented in a stabilizer comprising a rotor provided with stars, at least one of which comprises one of the above devices, and said star comprises at least one thick tooth which use at the same speed as said tool.

According to another characteristic, the invention is implemented by a tool which comprises at least one blade above; this tool is attached to the end of two arms rotatable on a horizontal axis perpendicular to the longitudinal axis of said tool; and the latter comprises means for rotating the arms so as to keep the device below the level of the ballast of a railway track; and it also comprises means for tensioning said compacting blade.

According to another characteristic, the method according to the invention can be implemented with a device comprising at least two other tools comprising a blade; these two blades are distributed transversely between ribs and between lateral faces, on one or more rows at the same depth or at different depths, to form a rigid frame, which makes it possible to compact at one time a layer of great thickness to form a compacted base at the desired density.

According to another characteristic, said blades are stepped in height to obtain a compacted layer whose height is greater than that obtainable with a single passage.

According to another characteristic, the compacting device for implementing the method of the invention comprises, before the compaction means themselves, a small diameter shaft provided with easily exchangeable peaks, to form a small milling cutter which separates the ballast soil before said compacting means to facilitate adjusting and compacting said layer; and the rotor is driven by a geared motor, located inside the vertical uprights forming a box.

According to another characteristic, the method according to the invention is intended for the treatment of soils under the ballast of railway tracks, and it comprises means for the preliminary excavation of at least one trench to engage the engine of the railway. a milling cutter, means for ensuring the adjustment of a binder, means for mixing said binder and said soil, and means for thick-layer compaction of said mixture; and these kneading means comprise a large diameter bur with a horizontal axis perpendicular to the direction of advance of the wagon and on which are fixed bodies such as teeth; which makes it possible to mix all the soil subjected to the treatment with said hydraulic binder.

According to another characteristic, the device according to the invention comprises probes, means for processing the signals of these probes, and means for adjusting the depth of the compacting tool according to the results of this signal processing.

• la fig. 1 : une vue en perspective cavalière d'un modèle de réalisation d'un outillage pour un procédé et un dispositif selon l'invention, limité à une dent de largeur relativement faible ;
• la fig. 2 : une vue de côté d'une variante de réalisation, comportant un gros rouleau au lieu d'une lame ;
• la fig. 3 : une vue de côté d'une variante de réalisation, comportant un alignement de rouleaux de petit diamètre ;
• la fig. 4 : une vue en coupe de la variante de la figure 3 ;
• la fig. 5 : une vue de côté d'un ensemble d'organes connus ;
• la fig. 6 : une vue de côté d'un autre mode de réalisation, utilisant des organes de la figure 5 ;
• la fig. 7 : une vue de côté d'un tracteur remorquant une première application d'un dispositif non revendiqué pour mettre en oeuvre un procédé selon l'invention;
• la fig. 8 : une vue de côté d'un rotor muni d'organes selon les figures 5 et 6 pour un dispositif selon l'invention ;
• les fig. 9 à 11 : des vues de côté de trois véhicules selon l'invention porteurs munis d'un rotor tel que celui de la fig. 8 ;
• la fig.12 : une vue de côté d'un wagon atelier pour mettre en oeuvre un troisième application du procédé selon l'invention ;
• la fig. 13 : une vue de dessus d'un cadre rigide muni de moyens pour mettre en oeuvre une première variante de l'invention;
• les fig. 14 et 15 : des vues de côté d'un wagon atelier muni dudit cadre rigide, en position respectivement de transport et de déplacement non revendiqué pour mettre en oeuvre un procédé selon l'invention;
• la fig. 16 : une vue partielle et en coupe de la fig. 15 ;
• la fig. 17 : une vue schématique d'un dispositif permettant de déplacer le cadre transversalement par rapport au wagon ; et
• les fig. 18 et 19 : des vues de côté et par-dessus d'un wagon atelier pour mettre en oeuvre une deuxième variante du procédé selon l'invention.

Other features and advantages of the invention will become clear in the following description, given by way of non-limiting example with reference to the appended figures which represent:

• the Fig. 1 : a perspective view of a model for making a tool for a method and a device according to the invention, limited to a tooth of relatively small width;
• the Fig. 2 : a side view of an alternative embodiment, comprising a large roll instead of a blade;
• the Fig. 3 : a side view of an alternative embodiment, comprising a small diameter roll alignment;
• the Fig. 4 : a sectional view of the variant of the figure 3 ;
• the Fig. 5 : a side view of a set of known organs;
• the Fig. 6 : a side view of another embodiment, using organs of the figure 5 ;
• the Fig. 7 : a side view of a tractor towing a first application of an unclaimed device to implement a method according to the invention;
• the Fig. 8 : a side view of a rotor with organs according to the Figures 5 and 6 for a device according to the invention;
• the Fig. 9 to 11 : side views of three vehicles according to the invention carriers provided with a rotor such as that of the Fig. 8 ;
• the fig.12 : a side view of a wagon workshop to implement a third application of the method according to the invention;
• the Fig. 13 : a top view of a rigid frame provided with means for implementing a first variant of the invention;
• the Fig. 14 and 15 : side views of a workshop wagon provided with said rigid frame, respectively transport position and displacement unclaimed to implement a method according to the invention;
• the Fig. 16 : a partial view in section of the Fig. 15 ;
• the Fig. 17 : a schematic view of a device for moving the frame transversely relative to the wagon; and
• the Fig. 18 and 19 : views from the side and over a wagon workshop to implement a second variant of the method according to the invention.

The principle of soil compaction according to the invention consists in that at first a soil compaction device carried by a machine is inserted into the soil at a determined depth H. This device comprises at least one tool, wedge-shaped, which has a convex surface, inclined downwards, from front to rear, of convexity turned towards the depth of the ground in the working position of the tool, namely in the recessed position in the ground, parallel to the ground, between a leading edge and a heel lying below the surface generated by the leading edge when moving the tool parallel to the ground. In a second step it advances this device by maintaining the depth determined below the surface, which allows to deform the soil by a height h equal to the difference in height between the front and the back of the corner. This difference, which is the shift between the trajectories described respectively by the leading edge and the heel, will also be called the eccentricity of the tool.

The convex underside of this tool works by compression, and thus the soil can be compacted to a greater thickness than that where top-of-soil compaction processes become ineffective.

The compaction is obtained by the impression of the tool in the ground, caused by the movement of the tool carried by a material. The depth of the footprint is equal to the eccentricity of the tool, that is to say the difference in height between the leading edge and the heel of the sole. It determines the amount of material brought into the soil just below. This height h must be related to the contribution that the soil can accept, without causing a break in view of its state. The thickness of the compacted layer corresponds to the difference in level between the upper part (compacted) and the lower part which reaches the degree of compactness melts this prescribed layer.

The energy used for compaction by this method is not constant. It varies significantly depending on the effort required to overcome the reaction of the soil that undergoes the deformation imposed by the tool. This can be low in the case of a very abundant soil with a low eccentricity of the tool. On the contrary, the energy may be too great compared to what the ground can accept without causing breakage, in the case of excessive eccentricity.

The effectiveness of the compacting device therefore depends on the choice of the eccentricity of the tool and the operating mode.

To allow some variation so as to allow a certain range, the figure 6 , which will be described in detail later, shows a device with a constant profile

From this it follows that, in the context of the invention, one can use many forms of tools, including tools where the eccentricity h is constant, others where the eccentricity can vary by setting, or d still others where the eccentricity may vary by rotation of the sole consisting of a flexible blade or a rigid articulated sole with compression spring, or also mixed tools with rollers to reduce the friction forces.

In the context of the invention will also describe the applications from compacting teeth mounted on a frame with a single translational movement, and such teeth mounted on the stars of a rotor.

Still within the scope of the invention will also be described the applications of the invention, given the compaction possibilities, under the railroad tracks for shaping the support of the ballast layer, also to treat "in situ" the ground below the railway track ballast and for the execution of foundation layers.

The tools represented on the figure 1 corresponds, for the sake of clarity, to a single tool of relatively small width suitable for use in a device according to the invention. If this tool can be used alone to treat a soil on a narrow width, several will be used to treat the soil to the necessary width, corresponding for example to a roadway of a road. This set of teeth will then be fixed on a frame, or a rotor, not shown in the figure, with the teeth arranged either staggered in several rows of the same frame, or on the stars (or branches) of a rotor at least one star compaction device which replaces a kneading tooth.

This tool is formed in this example of a tooth 101 itself wedge-shaped whose leading edge is directed forward, and which is fixed to an intermediate piece 103, itself welded to a vertical post 102 of frame or at the end of the branch of a rotor star. The plate of the piece 103 serves as a common base for all types of compacting tools. The tooth 101 covers the intermediate piece 103, on which it is fixed by a key 108 which allows to replace easily and low cost when worn. The frame 102 makes it possible to drive the tooth 101 under the surface of the ground to a depth such that the upper layer of the soil thus released can be treated from the surface by conventional means, unless it decided to compact a second layer, above the first to a lesser depth, in the case of realization of very thick layers.

This upper layer, of height H, not shown in the figure, is thus detached from the virtual surface 104 which separates the two layers, to slide on the upper surface of the tooth 101, to separate in two parts around the frame 102, and finally falling back of the device on the virtual surface 105 which corresponds to the virtual surface 104 which has descended from a depth h under the effect of compacting treatment. The lower face of the tooth 101 is slightly inclined upwards from front to back to clear this face of the surface 104 in order to avoid undesirable effects, due for example to the friction of this face on the surface 104.

Compaction, object of the invention, is realized, in the embodiment described here, by a blade 106 having a curved shape reproducing the compaction curve under the repeated effect of the passages of a compactor acting from the surface, whose concavity is directed upwards. This blade can be thin and flexible, or thick and rigid. The profile of this blade is made so that its front portion is located substantially at the rear of the tooth 101 so that, in the movement of the device forward, the lower surface of the blade 106 comes progressively tangent the surface 104, which is not virtual here since it has been released by the tooth, then gradually press on this surface to compact the ground so that the surface 104 comes to join the surface 105. The height h, corresponding the difference between the surfaces 104 and 105, is determined so that the lower layers below this surface 106 are compacted to the desired level.

If, however, a single pass does not achieve the desired degree of compaction, the tooling will be reworked as many times as necessary, taking into account the amount of soil that may be collected before failure. To prevent premature wear of the blade 106, it may for example be covered on its friction face by wear blades 107 arranged against each other. others perpendicular to the direction of device advancement. These wear blades will be fixed by any known means, such as for example welding points.

The desired eccentricity is obtained by the profile of the blade.

In a first case, where the blade is flexible, to limit the bending of the blade and thereby its eccentricity, can be maintained using rods 109 a state of permanent compression. These rods will be maintained using for example eyelets 110 fixed perpendicularly to the inner face of this blade 106, substantially at the lowest level of this blade and allowing them to slide at the other end through localized oblong holes 111 in the upper part of the blade 106. Thus the eccentricity of the blade varies freely between two values, depending on the soil reaction. The eccentricity is maximum when the head of the rods is in abutment against the outer face of the upper part of the blade, and it is minimal, or even zero, when the flexed blade is contained entirely within the surface. 104. This allows to compact with the maximum energy that the soil can accept before breaking. The selection of the appropriate tool is made, beforehand, from shear tests carried out in the laboratory.

In a second case, where the blade is rigid, it will give it a curved shape, corresponding to the desired average eccentricity, and it will eventually be fixed in place with means similar to the bodies 109 - 111, but firmly blocked. It can also be fixed at its front end with a transverse joint and hold it with a compression spring, not shown in the figure.

On the variant embodiment of the figure 2 , there is a corner 201, similar to the corner 101, fixed on a vertical upright, or a rotor branch, 202 with an intermediate piece 203 which is recalled that it serves as a base for all tools. The upper layer, again not shown in the figure, is peeled off by the corner 201 of the virtual surface 204 and undergoes the same treatment as in the previous example. However, in this case the wedge 201 is inclined downwards so that its lower face 211 comes to press the surface 204 to perform a first compaction which gives a real surface 214. The piece 206, fixed by bolts 220 to the plate of the base 203, is formed at the front by a sole of short length 215 and at the rear by a large cylinder which can be smooth or toothed, or include feet of sheep 210. This cylinder is tangent to the extension of the profile of the sole. The cylinder rotates freely about an axis 216 held by the cheeks of the part 206. In contact with the ground, the cylinder rolls and compact the ground with a minimum of resistance. The level of the actual surface 214 is lowered to the desired level 205. As in the first embodiment, the surface 205 is covered at the rear of these second compaction means by the cuttings originating from the stripping of the upper layer by the wedge 201, and which are treated as seen above.

In a third variant, represented on the Figures 3 and 4 , the pickling member is reduced to a single wear plate 301 particularly strong, tungsten carbide for example, fixed on an intermediate part 303 by welding or possibly by removable means. This intermediate piece serves, as above, common support to the blade 301 and organs described below. The upper layer of soil, not shown, is treated as in the two previous embodiments. The compacting of the virtual surface 304, to bring this surface 304 to the desired level of the surface 305 by compacting a height h, is obtained here by a set of small rollers 309 of small diameter. These rollers are arranged substantially next to each other, parallel to the surface of the ground and perpendicular to the axis of advance of the device. They are fixed on another intermediate piece 313 which has downwards here, the shape substantially of a U having two vertical wings located on the sides and delimiting the two lateral faces of the tool. Their height position is defined such that the highest is slightly lower than the attack tip of the blade 301, the second is slightly lower than the first, and so on. In this way, the last roll will be at the surface 305 and will complete the desired compaction of the bottom layer of soil.

We have shown on the figure 5 known members that can be used in a fourth embodiment.

These members comprise an intermediate part 503 which can be mounted on any support, such as for example a branch of a star 522, through a transverse hole 502 and a not shown bolt. It further comprises a longitudinal hole, not visible in the figure, for receiving tools for milling a soil, such as a peak 511 or a tooth 501/531, which are held by a key 504. It will be noted that the peak 511 and the tooth 531 are particularly reinforced compared to the standard tooth 501.

A fourth embodiment, represented according to a first example on the figure 6 comprises an intermediate piece as described above, supplemented by a flat piece 513 fixed, for example by welding, to the lower end of the piece 503 to obtain an intermediate piece within the meaning of the invention

This intermediate piece is fixed by its hole 502 to a vertical upright 522 of a frame, or at the end of a branch of a star. It is provided for example with a peak 511 or a tooth 531 of the same kind as the tooth 501 above, but particularly reinforced with respect to the teeth used in the art. This intermediate piece has a vertical central portion 514 consisting of a first U-shaped profile facing downwards, or two cheeks of relatively small width. This profile is provided with a hole 515 at the front for the engagement of an axis and on its rear three holes 516 staggered in height.

The compacting member 518 comprises a blade 519 of curved shape whose concavity is directed upwards, this blade reproducing the compaction curve under the repeated effect of the passage of a compactor acting from the surface, and two uprights, or walls, vertical 520 forming a second section U upwardly, interlocking from the outside or the inside or on horseback, in the room 514. This is also provided a hole 515 at the front, and on its rear three holes 521 staggered in height.

To fix this compacting part on the intermediate part, the piece 520 is presented which fits into the part 514, making the holes 515 coincide. The pieces are then held together by using a bolt or an axis passing through these two holes and moderately tightened in order to be able to rotate freely and without friction the workpiece 520 relative to the workpiece 514. The holes 516 and 521 on each of the workpieces are staggered in such a way that when the workpiece 518 is rotated, only one of the holes 521 is in front of only one of the holes 516 of the other piece 520, as shown at 521. This provides three positions of the parts relative to each other. In this way we obtain three possibilities for adjusting the height of the blade 519 relative to the part 513 and the corner 501. These three settings correspond to three compaction heights and three values of h.

A first application of the process according to the invention, represented on the figure 7 consists in mounting, on a chain tractor 712 for example, the compaction tool described 711. This device will preferably be fixed on the rear of the tractor for stability reasons of the assembly. This fixing is done here using two longitudinal arms 713 and 714 and a vertical part 715 forming a deformable parallelogram which will, with the aid of a jack 716 fixed between the rear of the tractor and the arm 714 , to fix the depression of the device in the ground.

The whole is represented on the figure 7 during a second pass of the device. The first pass made it possible to compact the soil deeply to obtain a first layer 701 compacted over a height h. For the second pass, the device is reassembled using the cylinder 716 of the height H2 to compact a second layer 702 resting on the first layer 701. This layer 702 itself will be compacted over a height h. The difference H2 - h is equal to the difference between the leading edge of the tooth and the lower part of the two tools 717 and 718 described below.

The device is composed of two rows of tools 717 and 718, such as those described above. They are preferably arranged in staggered rows and supported by supports 719 and 720. These supports are themselves fixed to a rigid frame 721 which is itself fixed directly to the vertical part 715. The fixing of the supports 719 and 720 to the frame 721 is itself steplessly adjustable with holes 723, to complete the action of cylinder 716.

Alternatively, the tools / supports / frame can be animated by a vibratory movement represented by the arrow 723 and obtained using a known mechanism and not shown. In this case only elastic means 722 of the "silentbloc" type are useful to prevent the transmission of vibrations to the tractor. This makes it possible to reduce the traction force to a certain extent and to increase the compaction efficiency in the case of certain soils.

According to another variant, the supports 719 and 720, as well as the compaction teeth 717 and 718, may be hollow so as to allow the passage of powdery binders under pressure and their dispersion above the compacted layer. A summary dispersion of the binder with this top soil is carried out using a small rotor of diameter substantially equal to H2, not shown in the figure. This improves the mechanical characteristics of the upper layer before it is compacted with the same means.

A second application of the process of the invention, represented on the figure 8 consists in mounting tools on the branches of a rotor 801 provided with stars 802. In this example, a device according to the invention with a single star is shown, and it comprises four arms. Two of these diametrically opposed arms support known members 804 and 814 such as those shown in FIG. figure 5 , and the other two diametrically opposed arms of the compaction members 803 described, such as those shown in FIG. figure 6 . Note the wear of the tooth 804 and the good behavior of the tooth 814, the latter having been reinforced according to the invention. It is therefore necessary to replace the worn tooth 804 with a reinforced tooth of the tooth type 814.

This application relates in particular to the apparatus according to the invention known as "stabilizer". It then requires the replacement on each star of at least one tooth (preferably two) by a compaction tool as described, to allow compaction of a band. It also requires the change of the other teeth by teeth performing the same work, but reinforced, for example by thickening or by a tungsten carbide pellet, to have a wear identical to that of compacting tools.

This makes it possible to compact the support soil and to mix the layer at the same time. In this second application, it is useful to place this rotor inside a thick and strong protection bell, which gives both protection against projections and is a chamber for mixing. The rotor / bell assembly is attached to a carrier, either at the front, in the middle or at the rear thereof, as shown respectively on the Figures 9 to 10 . In these exemplary embodiments, the carrier vehicles are provided with large diameter tires.

In the example of the figure 9 , where the bell 920 and the rotor 921 are fixed to the front of a machine 922, the means for driving the rotor in rotation are known and not shown, here and as in all the other figures, to facilitate the reading of those -this.

This second application makes it possible to compact the treated layer from bottom to top by successive passages of the compacting machine.

This is the case on the figure 9 , in which the bell 920 and the rotor 921 form a material dedicated to this application. In this embodiment, the rotor rotates in the direction of travel. This allows the soil 923 at the bottom of the layer to abut against a soil 924 already compacted. If the rotor rotated in the other direction, the compacted soil would be pushed forward towards a non-compacted soil abutting against a soil 924 already compacted. By doing so, it is possible to obtain a higher degree of compactness with a reduced risk of cracking. If the rotor rotated in the other direction, the compacted soil would pushed back towards a non-compacted soil, which would limit the compaction rate and lead to a risk of cracking.

The bell provided with its rotor can therefore be fixed, either at the front as shown on the figure 9 similar to a "vibrating ball" compactor, or in the center as on the figure 10 similar to a stabilizer, or the back of a powerful agricultural tractor, as on the figure 11 . We notice on the figure 9 that the bell has been provided with a screen 926 made of materials such as sheet metal, to prevent the projection of rubble and especially dust.

The advantage of benefiting from a specific equipment bell / rotor mounted for example at the rear of an agricultural tractor, or a carrier created for this purpose, is to reduce the costs of construction and operation by retaining only the specifications necessary for compaction.

In this case, the rotor can be fixed relative to the bell with protective housings at the front and rear such as the organs 926. These housings can be lowered by rotation for example. The diameter of the rotor can then be smaller. Moreover this material can have all the functions to automate the production.

Moreover, it is possible to add to the equipment a water tank and a watering boom located in the bell, to provide the materials to be compacted with additional water inside the bell, if necessary.

A third, relatively more complex application consists in applying the method according to the invention to the repair of railway tracks, as shown in FIG. figure 12 .

It is recalled that the ballast plays a role of spring and damper to transmit the ground forces due to the passage of trains and prevent the sleepers do not sink gradually into the ground.

However, as the trains pass, the pebbles that make up the ballast fragment by attrition, resulting in a settlement of the ballast and therefore a degradation of its performance.

To repair this, a specialized train is used with wagons equipped with a chassis 1501 and bogies 1502, which make it possible to raise the track, to screen the ballast, to reinforce it with new pebbles of good dimensions, and to proceed to setting of the track.

The invention proposes to use the method described above, without having to remove the track, to enable work to be performed such as the adjustment and compacting of the form under the ballast, the construction of a foundation layer by treatment in place, or the construction of a foundation layer with contribution of materials, serious, serious cements etc, after having proceeded to the earthworks necessary for the setting in safe. This work is then performed "in situ" under the ballast, without having to remove the rails and before the ballast treatment and lane adjustment operations.

For this purpose, a device is used which makes it possible to implement the method according to the invention. This device may be for example one of those described above, or any other device adapted to implement the method of the invention. In the case illustrated on the figure 12 , which represents a workshop car comprising a frame 1501 and bogies 1502, this wagon is provided with such a device 1520 adapted to implement the method of the invention. It comprises a blade 1528 whose cutting edge is directed towards the direction of advance of the wagon, that is to say to the left in the figure. This blade is inclined down from front to back to compact the soil according to the invention. The blade is as thin as possible to limit the settlement of the ballast against the sleepers and its recovery between these sleepers. The upper part of the blade is horizontal, or even slightly inclined to limit the friction forces in contact with the ballast.

The blade is fixed, in a manner described below, at the lower ends of two arms 1521. These two arms are extended upwards and connected at their upper ends by a not shown transverse jack. The lower parts of these two arms, to which is fixed the blade 1528 according to the invention, are constituted by two thin blades narrow and tapered capable of making their mark in the ballast which overflows each side of the track beyond the sleepers.

If necessary it could be useful to fix at the front of the wagon two known chain slicers in themselves, not shown in this figure but present on the figure 18 . They make it possible to make two lateral trenches at the border of the ballast to allow the lower ends of the arms to pass in order to obtain the positioning of these in the ground at the height corresponding to the layer to be treated. These trenches also make it possible, if necessary, to improve the drainage of the railway track.

The transverse cylinder meanwhile, pulls on the upper ends of the two arms 1521, so that when the blade 1528 is active, it exerts traction to tension this blade so as to reduce compressive stress and "in fine To reduce its thickness.

We can see in the figure only that of the left side in relation to the advancement, because it masks the one on the right side. It is the same for all the mechanism for fixing and adjusting the position of the compaction device.

These arms are rotatably attached to the ends of a shaft 1523. A longitudinal cylinder 1522 makes this rotation possible.

This shaft is itself fixed to the frame 1501 by triangulated arms 1524 which maintain the shaft above the rails, parallel to the axes of the wheels and substantially at the same height as these relative to the level of the rails. This axis 1523 overflows on both sides of the wagon to maintain the arms 1521 at the level where the ballast stops in width. It is thus possible to maintain the compacting device 1520 under the ballast at the interface between the latter and the ground.

Maintaining the desired depth is done by acting on a cylinder, for example using a servomechanism.

The arm assembly 1521, cylinders 1522 and compacting device 1520 is dimensioned such that this device is positioned with a correct angle so that the blade 1528 has its compacting effect on the ground beneath the ballast, for average dimensions. the thickness of the whole ballast / sleepers / rail.

Outside this average position, the adjustment by pivoting about the axis 1512 causes a certain variation in the positioning angle of the blade 1528. To overcome this variation, which plays a great deal on the packing effect, in this embodiment, for example two small cylinders 1526 and 1527 are used which make it possible to slightly modify the orientation of the lower part of the arm 1521 and therefore of the device 1520.

If necessary, it will be possible to use a servomechanism to keep the compacting device 1520 at the correct height and with good inclination by acting on the cylinders 1522 and 1526/1527.

The forces exerted on the compaction device 1520 tend to raise it, as well as all the rest of the wagon, quite significantly. It will therefore be necessary to have on the chassis of the car 1529 weights, whose number and weight will be determined experimentally.

It is clear that the assembly thus shown is in the operating position. To start the work it will be necessary to perform earthworks to set up the compaction device 1520.

For this the blade 1528 is detached from the uprights 1521. The assembly is carried out during the advancement of the wagon on approach by the engagement of tenons uprights 1521, not shown here, in housing integral with the blade. Unrepresented locks block everything. This assembly and disassembly operation is to be repeated from time to time to change the blade 1528, when the degree of wear of the blade will be too advanced and between each daily worksite interruption. The blade remains in place.

According to another variant of the method according to the invention, useful for example for compacting a thicker layer, it is possible to use a rigid frame 1610 such as that shown alone on the figure 13 , and fixed on a car represented on the Figures 14 and 15 . The figure 16 represents a partial and enlarged view of the figure 15 , limited to the active part of box 1610. Finally, the figure 17 schematically represents a device for moving the frame transversely relative to the wagon.

On the figure 14 , the frame 1610 is in the raised position, for example to move the wagon between two working positions.

On the figure 15 this frame is lowered into the working position to be able to compact the thickness of the ground 1607 located under the ballast layer 1606.

The displacement of the frame between these two positions is by sliding along four vertical posts fixed to the wagon so as to correspond to the four corners of the frame. It is blocked on the posts by known means, bolts for example.

To allow transverse displacement of the frame, each post is in this example attached to two cylindrical bars 1631 placed respectively above and below the frame 1501. These bars can slide in hollow cylinders 1632 fixed, for example by welding on the top and on the underside of the chassis. We can thus decenter the frame on the right as on the left, according to the needs of the building site. We can also use more or less large frames, depending on the available material for example.

This frame comprises for example two side plates 1611 which are fixed together at their lower part by two blades according to the invention 1619. Two stiffeners 1614, in the figure, make it possible to stiffen the assembly, to form a frame rigid which supports without deforming the forces which will be applied to it during the compaction.

According to another variant, the blades are shorter and their length is equal to the distance between a side plate 1611 and the stiffener 1614 closest thereto. The inter-axes of these side plates between each and the closest stiffener, as well as the between-axis between the stiffeners are the same, so as to have these blades staggered.

In this exemplary embodiment, two other plates 1621 are attached to the lateral plates, outside and at a small distance from them, which have a plow blade profile at the front, so as to push back laterally. ballast and reduce traction efforts.

In the case illustrated on Figures 13 to 16 this frame supports two blades 1619 whose cutting edge is directed towards the direction of advance of the wagon, that is to say to the left in the figures. These blades are inclined down from front to back to be able to compact the ground according to the invention. The number of blades is fixed here to be able to treat in a single pass the entire layer.

They can also be arranged recessed in height and back, in the manner of the steps of a staircase, at different depths, so as to compact in a single pass a thicker layer. The inclination of the blades is different. It corresponds to the thickness and the density of the compacted layer to obtain the same density.

The height of attachment and the number of different blades are fixed relative to the thickness of the layer 1607 and the height of the fraction of this layer that can be compacted by each of the blades.

The invention further proposes, to promote the penetration of the blades 1619, to place in front of said blades a mini rotor, or small strawberry, 1616.

This cutter is formed, in this embodiment, by a small diameter shaft 1656 supporting a set of tools 1666, such as peaks for example, fixed regularly on this shaft. Each peak is disposed in a cylindrical or slightly conical housing where it is held by a ring. Each housing is extended by a cylindrical hole of small diameter opening diametrically on the other side of the housing. These holes can drive the peaks when they are worn.

The shaft is secured to the side plates and ribs 1614 by bearings. It is rotated relatively fast relative to the progress of the wagon by known means such as hydraulic geared motors 1617, fixed in this example inside the boxes formed by the space between the plates 1611 and 1621, which protects them against the friction of the lands or the ballast of the furrows and against the projections of all kinds resulting from the treatment of the ground.

The advantage of this arrangement lies in the fact that the bur breaks the ballast / soil interface to separate them more easily, in order to treat the ballast on the one hand and to compact the soil on the other hand

The fact of having several blades for compaction makes it possible to reinforce the structure of the compacting tool, which is subjected to significant deformation forces, giving it greater rigidity. It also makes it possible to compact in a single passage a greater thickness. By proceeding in this way, the support platform is of better quality and yields are increased.

The ballast 1606 is processed by known means, not shown, which sort the pebbles become too small and replace them with normal-sized pebbles, resulting in the thickening of the layer 1627 ballast to the back of the soil treatment organs. We notice, of course, the figures 15 and 16 , that the upper surface of the ground 1607 and compacted is lower than the upper surface of the ground 1627, which corresponds to the increase in thickness of the ballast layer, due to the treatment thereof.

Note also the two veins 1627 compacted soil, which extend below the ballast and treated 1626.

A second variant of the previous application, shown from the side on the figure 18 , and on top of figure 19 allows the treatment in place of the soil.

For this, we use a car very similar to that of Figures 14 and 15 and for the clarity of the figures, only the different members between these two groups of figures have been referenced.

The wagon is thus provided with a frame 610 which comprises devices (here three blades) 619 according to the invention for simultaneously compacting and treating a layer 507 of the ground situated under the ballast 606, which is treated at the same time by one methods described above, to give a revamped ballast layer 521.

The soil is initially separated from the ballast by a thin and strong blade 615 placed at the front of the frame.

This soil thus exposed is triturated and expanded to the desired thickness by a large rotor, or mill, 616. This is formed, in a known manner, by a shaft provided with members such as picks, chisels, etc.

During this operation, products are poured onto the ground, by means known in the art that are not shown, intended to improve its physical characteristics, for example a hydraulic binder. The nature and volume of these products are determined in advance by a soil analysis.

The products thus spread are intimately mixed with the soil by the action of the strawberry.

The mixture thus obtained can then be compacted by the devices 619 to obtain a soil 527 with improved characteristics both by treatment and compacting.

The milling cutter 615 is driven by motors 617 which overflow on each side of the frame. To let them pass, the method according to the invention proposes to provide on each side of the car a trench of sufficient size. For this, we will use slicers 601 of known type.

The device according to the invention also allows a servo-control between the machine parameters and the compactness rate to be obtained, in order to provide driving assistance as well as continuous monitoring and control of the compaction.

It is recalled that the device according to the invention compacts a thin layer. This thickness is related to the deformation, imposed by the profile of the sole, the required compactness rate with a single passage of the material.

Under these conditions the friction forces of the sole in contact with the ground and the pressure exerted by the equipment must at all times be identical. To know these values, according to the application, one measures, during a test board, using sensors or probes for example, carefully selected parameters, correlated with the friction forces and the pressure. exercised. Then, during compaction, simply adjust the depth of the compaction tool continuously to match the values of the parameters measured during compaction, with the reference values defined during the test. The permanent adjustment of the depth can be automated. If these are too low, the thickness of the layer should be reduced.

Otherwise, if the measured parameters are higher than the reference values, to satisfy the conditions of compaction, the thickness of the layer must be increased.

By proceeding in the same manner, layer by layer, progressively raising the sole of the tool, the total thickness required is obtained with a regular compactness rate, substantially constant and independent of the depth.

According to another embodiment of the invention, by adding to the preceding device a guidance system and positioning in x, y, z, with recording, one can obtain continuous and controlled compaction.

In the case of the invention, each passage makes it possible to obtain the desired level of compactness over a reduced layer thickness, provided that the thickness of the layer is constantly adjusted, since the tool is worn. For this, from the response of the ground / equipment pair, it suffices to make the necessary adjustments. The compaction of a larger layer will require several passes under the same conditions after having each time raised the tool by the thickness of the previously compacted layer. In the end, this makes it possible to obtain a compacted layer of the desired thickness, with a regular and high level of compactness throughout its thickness.

In the case of compaction with usual means, the compactor multiplies the number of passages, as long as the rigidity of the measured platform is sufficient. However, this procedure does not make it possible to be certain of obtaining the required level of compactness at the bottom of the layer, the compactness gradient being decreasing.

The servo-control method proposed is to use sensor information to measure tensile and mass forces in the case of displacement compaction, and in addition to using sensors for the measurement of vibrations or accelerations in the case of compaction by displacement and rotation of the tools, to correlate these measurements with the compactness curves obtained elsewhere, to determine the optimal operating conditions.

Under these conditions, it is possible to vary by servo the depth of the tool so that the "response" corresponds permanently to the reference determined from the realization of a test board.

By preferably associating a device for positioning and measuring the depth of the tool, with recording, the material receives the information necessary to proceed to a new passage, and this until the layer corresponding to the projected thickness of the material is obtained. compactness rate prescribed on any height.

Claims (11)

1. Method for compacting soils, wherein in a first stage, a soil compacting device (101-103; 107-109) is inserted into the soil (104, 105), at a specified depth (H), and comprises at least one wedge-shaped tool having a convex surface, tilted downwards, from front to rear, with a convexity toward soil depth in a working position of the tool, namely in a position pressed into the soil and parallel to the soil, between a leading edge formed by the ridge of the wedge-shaped tool and a heel at the other end of the convex surface and arranged below the surface generated by the leading edge when the tool is advanced parallel to the soil, and wherein in a second stage, this device is advanced while being maintaining at the specified depth, which allows a continuous soil compacting at a depth where the methods for compacting from above the soil become ineffective.
2. Device for compacting soils, comprising a rotor (801) having at least one star provided with a set of spokes (802), wherein a wedge-shaped tool has a convex surface and is attached at the end of at least one of said spokes, the rotor being rotated and being disposed under a protective hood (920), the whole assembly being driven in a translation movement which is horizontal and perpendicular to the axis of the rotor to compact a land strip (924) with a width inferior to the width of the hood, characterized in that, in the working position of the tool, namely in the lowest position of the end of said spoke, the tool is pressed into the soil, the convex surface of the tool being tilted downwards, from front to rear, with a convexity toward soil depth, between a leading edge formed by the ridge of the wedge-shaped tool and a heel at the other end of the convex surface and arranged below the surface generated by the leading edge when the tool is advanced.
3. Device according to claim 2, wherein the or each wedge-shaped tool (101) is a tooth whose leading edge is facing forward in order to remove the upper layers of the soil, said tooth being attached on a frame (102) by an intermediate part (103) acting as a common support for the tooth and for a blade (106) which is also attached at the rear of the tooth and has a curved shape whose concavity is facing upwards, whose front is at the bottom level (104) of the removed soil and whose lowest portion is at the desired level of compaction for a single pass of the device.
4. Device according to claim 3, wherein the blade (106) acts itself as a spring or is attached at its front end by a transverse joint and is maintained compressed by a spring.
5. Device according to claim 2, wherein the or each one wedge-shaped tool (201) is a tooth whose leading edge is facing forward in order to remove the upper layers of the soil and whose bottom portion (211) is tilted downwards to perform a first compaction at an intermediate level (214); said tooth being attached to a frame (202) by an intermediate part (203) which also supports, at the rear of the tooth, a compacting roller (209) for performing a second compaction to obtain the desired level (205), said roller being smooth or ridged, or supporting sheep's foot rollers (210).
6. Device according to claim 2, comprising a single wear blade (301) tilted from front to rear to remove the upper layers of the soil; said blade being attached on a frame (302) by an intermediate part (303) acting as a common support for the blade (301) and a set of rollers (309) attached to a second intermediate part (313) which in turn is attached to the first part; these rollers being disposed substantially next to each other, parallel to the soil surface and perpendicular to the advance direction of the device; the first of these rollers being further located slightly below the leading edge of the wear blade (301), and the other rollers being slightly shifted in depth so that the last one is at the desired level for the depth of compaction (h).
7. Device according to claim 2, comprising an intermediate part provided with a known support (503), which includes a longitudinal hole (502) for receiving soil decompacting tools, such as a chisel (511) or a tooth (501), wherein a flat part (513) is added on the lower portion of said support (503), said flat part (513) being attached on the lower end of said support (503); said flat part being provided, on its lower portion, with a first vertical fin provided with a hole (515) at the front and, at its rear, with three holes (516) spaced in the height direction, this assembly (503, 513, 514) forming said intermediate part; and wherein the device also includes a compacting part (518) provided with a blade (519) having a curved shape whose concavity is facing upwards, said blade reproducing the curve of settlement under the repeated effect of the passage of a compactor acting from the surface; said blade (519) comprising a second vertical fin (520) attached on the upper portion of the blade (519) and being itself provided with a hole (515) at the front and, at its rear, with three holes spaced in the height direction; these two fins being positioned against one another by aligning the two front holes (515) and by pushing into these two holes fastening means which allow rotation of the second fin (520) on the surface of the first fin (514), the rear holes (516, 521) on each of these fins being spaced so that, when the second fin (520) is rotated on the first fin, only one of the rear holes thereof corresponds to only one rear hole of the first fin (519); which allows to obtain three positions of the fins relative to each other and thus three different eccentricities for said blade (519).
8. Device according to one of claims 2 to 7, wherein the direction of rotation of the rotor (920) is the same as the advance direction of the whole assembly.
9. Device according to one of claims 2 to 8, wherein the rotor/hood assembly (920, 921) is attached to a carrier vehicle (922) either at the front, at the middle or at the rear of said vehicle.
10. Device according to claim 9, wherein the carrier vehicle is a stabilizer comprising a rotor (921) provided with stars, at least one of the stars being provided with a wedge-shaped tool (803), and said star having at least one thick tooth (814) which wears at the same rate as said wedge-shaped tool.
11. Device according to one of claims 2 to 10, comprising probes, means for processing signals from these probes, and means for adjusting the depth of the compacting tool based on the results of the signal processing.

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