Machine for Making a Continuous Wall in the Ground

Abstract

The machine for making a continuous wall in the ground comprises a rear portion having means for filling the portion of trench located behind the machine with concrete; a front portion having cutter means for making a portion of trench in front of the machine; and means for modifying the distance between said front and rear portions in a horizontal direction. The machine is characterized in that said cutter means include vertical guide means, at least one rotary cutter having an axis of rotation that is horizontal and parallel to the width of the trench, and means for moving said cutter along the guide means between a bottom position corresponding to the bottom of the trench and a top position disposed above the trench, said cutter being suitable both for cutting the ground of the trench and for kneading it in order to obtain a material in the pasty state.

Description

This is a 371 national phase application of PCT/FR2006/050941 filed 25 Sep. 2006, claiming priority to French Patent Application No. FR 0509956 filed 29 Sep. 2005, the contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a machine for making a continuous wall in the ground, and to a method of making such a wall.

BACKGROUND OF THE INVENTION

To make continuous walls in the ground, the technology that is most commonly used consists in digging a trench corresponding to the path of the wall that is to be made, and filling the trench with concrete, possibly together with reinforcement. More precisely, the trench is usually made in successive sections, with a dug section of trench then being filled with concrete to constitute a panel of the continuous wall.

When the depth of the wall that is to be made is not very great, it is possible to use an excavator machine that is moved along the trench as the various sections of the trench are made.

U.S. Pat. No. 3,893,302 describes a machine and a method of excavating trenches and constructing walls in the excavated trenches. The machine comprises a cutter tool disposed in the front portion of the machine, which tool is in the form of an endless excavator chain carrying buckets. The rear portion of the machine has a vertical duct for delivering concrete from a container situated outside the trench to behind the machine so as to fill the trench that has just been dug.

That machine presents a certain number of drawbacks, and in particular from the fact that the continuous bucket chain does not enable the trench to be extracted in all types of terrain, in particular such a cutter tool cannot be used in hard terrain. It is known that certain trenches need to be made in geological layers of differing hardnesses.

SUMMARY OF THE INVENTION

A first object of the present invention is to provide a machine for making continuous walls in the ground and that remedies the above-mentioned drawbacks.

To achieve this object, the machine for making a continuous wall in the ground comprises:

• • a rear portion comprising:
    • first anchor means for anchoring in the side walls of the trench; and
    • means for filling the portion of the trench located behind the machine with concrete;
  • a front portion comprising:
    • second anchor means for anchoring in the side walls of the trench;
    • cutter means for making a portion of trench in front of the machine;
    • extractor means for extracting the ground cut away by the cutter means; and
  • means for modifying the distance between said front and rear portions in a horizontal direction;

the machine being characterized in that said cutter means comprise:

• • vertical guide means;
  • at least one rotary cutter having an axis of rotation that is horizontal and parallel to the width of the trench; and
  • means for moving said cutter along the guide means between a bottom position corresponding to the bottom of a trench and a top position disposed above the trench, said cutter being suitable both for cutting the ground of the trench and for kneading it in order to obtain a material in the pasty state.

It will be understood that by using a cutter having its axis of rotation horizontal and perpendicular to the length of the trench, the cutter can indeed be fitted with tools that are capable of passing through all of the layers of terrain that are conventionally present in building sites. Such cutter tools can be constituted by cutter picks.

In addition, during its upward and downward movements along the full height of the trench, the cutter acts not only to cut the ground, but also to knead it together with the water that is usually naturally present in the ground. This produces a material in the pasty state that can subsequently be extracted easily.

In some circumstances, it is desirable to inject materials during digging, in particular if the quantity of water that is already present is not sufficient for obtaining the pasty state. Such materials may be mud, with or without polymer, and also ground conditioning additives for modifying its consistency and/or its permeability.

Another object of the invention is to provide a method of making continuous walls in the ground making use particularly but not exclusively of the above-described excavator machine.

The method of making a continuous wall in the ground comprises the steps of:

• • digging a trench in the ground in successive sections with the help of a machine that moves horizontally in the trench;
  • extracting the ground corresponding to digging the successive sections of the trench;
  • moving the machine in successive steps corresponding to the sections of the trench; and
  • filling the section of trench located behind the machine with concrete;

said method being characterized in that the digging of sections of trench is performed by vertically moving a rotary tool suitable both for cutting the ground in the trench and for kneading the ground cuttings in the trench in order to transform them into a material in the pasty state.

Other characteristics and advantages of the invention appear better on reading the following description of various embodiments of the invention given as non-limiting examples.

BRIEF DESCRIPTION OF THE DRAWINGS

The description refers to the accompanying figures, in which:

FIG. 1 is a perspective view showing the excavator machine as a whole, outside the wall and carried by a handling crane;

FIG. 2 is a perspective view showing the bottom portion of the excavator machine;

FIG. 3 is a perspective view showing a preferred embodiment of means for extracting material in a pasty state;

FIG. 4 is a plan view of the bottom portion of the machine; and

FIG. 5 is a perspective view showing the machine as a whole while in use.

DETAILED DESCRIPTION

FIG. 1 shows a handling crane comprising a platform 10 preferably fitted with crawler tracks 12 and carrying a substantially vertical boom 14. This boom serves to support cables forming a pulley block 16 with the excavator machine proper 18 being suspended from the bottom ends of the cables. The cutter tool of the excavator machine is a cutter 20 that is described in greater detail below. The cutter 20 can be moved vertically along the structure of the excavator machine 18 with the help of a control bar 22 or “kelly”. The control bar 22 can be moved vertically with the help of a winch on the handling crane. Reference 24 identifies a structure for guiding the control bar 22 at the surface.

With reference more particularly to FIGS. 2 and 4, there follows a description of a preferred embodiment of the excavator machine 18. It is constituted by a front portion 26 and by a rear portion 28.

The front portion 26 comprises a structure constituting a vertical guide part 29, a device for extracting ground cuttings 30, and preferably tubes for injecting a liquid additive into the cuttings, these tubes being referenced 32 and 34. The front portion 26 also has two series of two side shoes for anchoring in the side walls of the trench and given respective references 36 and 38. These shoes are controlled by actuators 40. In the extended position, the shoes 36 and 38 press against the walls 42 of the trench, thereby holding the front portion 26 of the excavator machine stationary.

The rear portion 28 of the excavator machine is constituted essentially by a vertical structure 44 and by a pipe 46 for pouring concrete into the section of trench that has been made. The rear portion 28 also has two sets of guide shoes 48 and 50 controlled by actuators 52. In the extended position, the shoes 48 and 50 form anchor means engaging the side walls 42 of the trench and thereby holding the rear portion 28 of the excavator machine 18 stationary.

The front portion 26 is also fitted with the cutter tool 20 mounted at the bottom end of the control bar 22. The cutter tool is preferably constituted by a cutter comprising two drums 54 and 56 of horizontal axis parallel to the width of the trench to be made. The cutter is mounted to rotate on a support 58 that is guided to move in translation by the guide part 29. The drums 54 and 56 are fitted with conventional cutter picks 59.

In a variant embodiment, the cutter tool 20 constituted by the drums 54 and 56 could be mounted on a support that is guided by the vertical guide 29, the support being fitted with a motor enabling the cutter tool 20 to be moved in translation between a bottom position corresponding to the bottom of the trench and a top position in which the cutter tool is disposed above the trench.

The front and rear portions 26 and 28 of the excavator machine are interconnected by at least two horizontally-acting actuators, respectively a bottom actuator 60 and a top actuator 62. These actuators serve to vary the horizontal distance between the front and rear portions 26 and 28 of the excavator machine and to apply thrust on the front portion 26 of the excavator machine. This intermediate portion of the excavator machine is preferably also fitted with a system 64 for enabling the front and rear portions to take up a certain angle in a horizontal plane. By way of example, this system can be constituted by a control actuator 66 mounted on the cylinder of the top actuator 62, the control actuator 66 controlling a link 68 having one end secured to the end of the rod of the control actuator 66 and another end connected to the structure of the front portion 26 of the excavator machine. A second link 70 co-operates with the first link 68 to constitute a deformable parallelogram. It can thus be understood that by controlling the control actuator 66, it is possible to give a certain angle to the front portion 26 of the excavator machine relative to its rear portion in a horizontal plane. Thus, it is possible to make a trench that is not rectilinear. Prior to imparting such an angle, the cutter tool 20 is caused to be raised so that it is located above the trench. This makes it easier to obtain an angle since the cutter tool does not oppose resistance to taking up an angle.

FIG. 3 shows a preferred embodiment of the system 30 for extracting cuttings. The extractor system is constituted by a cylindrical part 80 of height not less than the height of the structure of the excavator machine. Within this cylindrical part 80 an auger 82 is mounted to rotate about a vertical shaft 84. The top portion of the part 80 has a motor 86 mounted thereon for turning the auger. The top end of the part 80 also has an outlet for delivering the expected cuttings. The cylindrical part 80 has a plurality of openings up its height such as 88 that are of large dimensions so as to enable the cuttings for removal to be placed on the auger 82.

Naturally, other cutting-extractor systems could be used, e.g. a bucket chain or a telescopic tube provided with a valve, or indeed a flexible tube flattened by wheels using the principle of peristaltic pumps, and providing the means in question are not purely hydraulic.

The term extractor means that are not purely hydraulic is used herein to cover means that do not make use of the debris that results from the action of the cutter tool being put into suspension in a liquid. In particular, the use of such extractor means is made possible by the fact that the ground cuttings are transformed into a material in the pasty state. The fact that debris is extracted without using large quantities of liquid considerably simplifies the processing of the spoil.

There follows a description of how the above-described machine is used, and thus of the method of the invention for making a continuous wall in the ground.

A first section, constituting one panel having the depth of the work, is made by using conventional means such as a cable bucket or a hydraulic bucket. The width of this first section of trench corresponds to the width dimension of the excavator machine. To ensure stability of the terrain, the panel is filled with mud.

The excavator machine 18 is then inserted into this section of trench, and then it is positioned so as to begin the horizontal digging process. For this purpose, the machine is initially held stationary by the front actuators 36 and 38. The cutter tool 20 is caused to penetrate vertically into the ground. As explained above, this cutter tool is constituted by a cutter having drums that are driven, preferably by a hydraulic motor, the drums being provided with cutter picks.

The cutting capacity of such a tool is suitable for enabling it to pass through all of the layers of terrain that are conventionally present on building sites. During this descent stage, cuttings are not extracted. They are cut away and mixed with water present in the ground and preferably also with materials injected by the pipes 32 and 34 during digging. These materials may be mud with or without polymer and ground-conditioning additives for modifying its consistency and/or its permeability. Thus, the drums serve not only to cut the ground in order to make the trench, but also to knead the ground cuttings. Once the cutter tool 20 has reached the bottom, it may optionally change its direction of rotation and rise towards the surface. During the upward and downward movements of the cutter tool, it acts not only to cut the ground but also to knead the ground cuttings in order to transform them into a material in the pasty state.

When a section of trench has been extracted and transformed into material in the pasty state, the rear shoes 50 and 52 are put into the extended position in order to anchor the rear portion 28 of the machine in the trench, and the front shoes are retracted. Taking their reaction from the rear shoes, the horizontal actuators 60 and 62 apply thrust to the front portion 26 of the excavator machine and in particular to the system 30 for extracting material in the pasty state. This thrust enables the extractor system to be fed through the openings 82. The auger 84 then extracts the material in the pasty state.

In the following step, the front side shoes 36 and 38 are moved to the extended position in order to anchor the front portion 26 of the extractor machine, and the rear shoes are retracted. The horizontal actuators 60 and 62 are retracted so as to cause the rear portion 28 to move closer to the front portion 26, thereby releasing a section of trench behind the machine. This section of trench is filled immediately with concrete or with other materials suitable for this kind of work with the help of the concreting system 46. It will be understood that during the concreting operation, while the excavator machine is held stationary by its front shoes, it is possible to restart the digging stage with the help of the cutter tool 20 so as to make a new section of trench.

The cutting front of the trench is supported by the cutter tool 20 bearing against the terrain in the pasty state. Lateral support can be provided by a biodegradable fluid exerting hydrostatic pressure on the limited volume of the thrust module.

It is also possible to verify that the excavator machine is vertical. The top and bottom pairs of thrust shoes respectively in the front portion 26 and in the rear portion 28 of the excavator machine make it possible to ensure that the structure of the machine is indeed in a vertical position. Such position monitoring is performed prior to inserting the cutter tool for the purpose of making the next section of trench. Any error in verticality can be corrected by acting appropriately on the various front & rear, and bottom & top shoes.

In addition, as mentioned above, the excavator machine preferably includes a system 64 for enabling a certain angle to be imparted in a horizontal plane between the front and rear portions 26 and 28 of the excavator machine. This makes it possible to make a trench that is not rectilinear, or on the contrary, when making a rectilinear trench, to correct for any horizontal path error.

Claims

1. A machine for making a continuous wall in the ground, the machine comprising:

a rear portion comprising: a first anchor device for anchoring in the side walls of the trench; and a device for filling the portion of the trench located behind the machine with concrete;

a front portion comprising: a second anchor device for anchoring in the side walls of the trench; a cutter device for making a portion of trench in front of the machine comprising a vertical guide device, at least one rotary cutter having an axis of rotation that is horizontal and parallel to the width of the trench; and a device for moving said cutter along the guide device between a bottom position corresponding to the bottom of a trench and a top position disposed above the trench, said cutter being suitable for cutting the ground of the trench and for kneading it in order to obtain a material in the pasty state; an extractor apparatus for extracting the ground cut away by the cutter device; and

a device for modifying the distance between said front and rear portions in a horizontal direction.

2. A machine according to claim 1, wherein said front portion further comprises an injector device for injecting a liquid additive into the ground cuttings in order to facilitate obtaining material in a pasty state.

3. A machine according to claim 1, wherein said cutter is mounted on a support that is constrained to move along a vertical guide device, said support being moved with the help of a vertical control bar.

4. A machine according to claim 3, wherein said control bar is moved by means of a winch of a handling crane.

5. A machine according to claim 1, wherein said cutter is mounted on a support constrained to move along a vertical guide device, said support being fitted with a motor apparatus.

6. A machine according to claim 1, wherein said device for extracting material in the pasty state is a device that is not purely hydraulic.

7. A machine according to claim 6, said extractor apparatus comprises a hollow cylindrical part extending substantially along the entire height of the trench and pierced with openings facing towards the front of the machine, together with a vertical-axis auger mounted in said cylindrical part.

8. A machine according to claim 7, wherein said device for modifying horizontal distance is suitable for applying thrust to the front portion of the machine when said first anchor device is activated.

9. A machine according to claim 1, further comprising a device for imparting an angle in a horizontal plane between the front and rear portions of the machine.

10. A method of making a continuous wall in the ground, the method comprising the steps of:

digging a trench in the ground in successive sections with the help of a machine that moves horizontally in the trench;

extracting the ground by digging the successive sections of the trench;

moving the machine in successive steps corresponding to the sections of the trench; and

filling the section of trench located behind the machine with concrete;

wherein each of the trench sections is dug by moving a rotary tool solely in a vertical direction, which rotary tool is suitable, during vertical downward movement, for cutting the ground in the trench, and during both the vertical downward movement and the vertical upward movement of the rotary tool, for kneading the cut ground in the trench in order to transform it into a material in the pasty state.

11. A method according to claim 10, wherein an additive is injected into the ground cuttings in order to facilitate obtaining the material in the pasty state.

12. A method according to claim 10, wherein the cutter tool is a rotary cutter having an axis of rotation that is orthogonal to the travel direction of the machine, said cutter being moved vertically.

13. A method according to claim 10, wherein the material in the pasty state is extracted from the trench with the help of a system that is not purely hydraulic and that is mounted on the machine.

14. A method according to claim 10, wherein forward thrust is exerted with the help of a machine for maintaining the cutting front of the trench.

15. A method according to claim 10, wherein a certain angle is imparted in a horizontal plane between the front and rear portions of the excavator machine in order to make a trench that is not rectilinear.