FR2697551A1 - Improved device for the treatment of floors by rotary jet (s). - Google Patents

Abstract

The invention relates to a device for treating the land by a jet comprising a string (1) of rods or tubes (2) coupled to one after another, a device (7, 8) for driving the string of rods or tubes in terms of rotation and, if desired, in terms of translation, mounted on the upper part of the said string, at least one ejection nozzle (4, 5) provided at the lower part of the said string, at least one source (11, 13) of fluid under high pressure, and a pipe connecting the source of high pressure fluid to the said nozzle, characterized in that the device for driving the string of rods or tubes imparts to the latter a reciprocating rotational movement and the feed pipe consists of a flexible hose (10, 12) connecting the said source to the said nozzle. Use in the civil engineering field.

Description

The invention relates to an improved device for the

  Rotary jet soil treatment (s).

  The rotary jet (s) soil treatment method is well known and is used for the production of columnar reinforcing elements and screens

  sealing in the mass of a permeable ground.

  According to this method, an exogenous material or grout is introduced into the field under consideration from a borehole in the form of at least one suitably high-speed directed jet which, in its path, deconstructs the ground in place, and the nature of the said terrain, or mixes with the constituent elements of the latter and leads, after setting, to the formation of a mortar or soil concrete (for example, gravely or sandy ground), or simply replaces the ground and leads, after setting, to the formation of a hardened grout (case, for example, clay soil) or jet (s), depending on the flow, the driving pressure and

  characteristics of the terrain, have a certain radius of action.

  If the tool providing the formation of the jet is rotated

  slow translation inside the borehole, we obtain a more or less cylindrical volume of treated ground having for radius the radius of action of the jet or jets under the conditions considered, and a height corresponding to

  the amplitude of the translational movement.

  It is easily understood that it is thus possible to achieve, by this jet technique, sealing screens by the juxtaposition of a plurality of cylindrical elements (or columns) of land and treated at a certain height, made from a mesh of parallel boreholes of density such that the elements or columns are

  intersect to form a continuous mass.

  The jets used can be of various types, that is,

  that is to say consist of a single grout, or a grout jet surrounded by an air jet ring to increase the radius of action, or a combination of a jet of water surrounded by an annular air jet ensuring the destructuration of the ground and a separate jet of grout, usually provided at a lower level than the jet of water. For the implementation of this method, it is customary to use a device comprising a grouting plant producing slurry feed to one or more connected pumps, via a rotary joint, to an introduced tube train. in the drilling o must be done by jet treatment The train of tubes can be driven in translation and rotation by means of a hydraulic rotary head enclosing the upper end of the tube train, which is itself mounted on a drill pipe La or the pumps deliver the destructuring fluid (grout or water) at pressures of the order of

200 to 700 bars or more.

  The tube train is formed of connectable unitary tubular sections with appropriate seals and each section can be formed of a single tube (single jet) or several coaxial tubes (double or triple jet) Liquids (grout, water ) are ejected by one or more nozzle (s) with a diameter of approximately 2 to 4 mm The tube train sections may have a diameter of 50

about 200 mm.

  A drilling tool may be provided, furthermore,

  below the nozzles, at the lower end of the tube train to carry out the drilling in which the treatment will be carried out Alternatively, the drilling may be performed

  previously by a separate device.

  In practice the jet treatment is started by positioning the jet device at the bottom of the borehole, driving the tube train in a rotational and translational motion towards the head of the borehole until

  obtain a treated field column of the desired height.

  During this translational movement, the upper part of the tube train projects more and more in relation to the surface of the ground. This is not a problem when working under normal site conditions, for example.

example in the open air.

  It happens, however, that we have to work in such conditions (reduced height ceiling, narrow working chamber, etc.) that we do not have in the axis of drilling the necessary space to sufficiently raise the tube train during treatment In this case, it must be disassembled during treatment to remove the stump

tubular upper of the train.

  Such disassembly is however undesirable, in the case of coaxial tubes defining two or more feed channels, because it creates the risk that grout enters the air or water supply duct, which causes the recovery of

  treatment damages or clogs the ejector nozzles.

  Also, during disassembly, it is necessary to stop the supply of fluids and there is the risk that there will be an inadvertent return of ejected grout from

plug the nozzles.

  Finally, note that the trains of coaxial tubes

  are, in a general way; relatively expensive.

  There is therefore a need for a jet treatment device that would allow working in low ceiling spaces or cramped spaces without having to interrupt the

  treatment during a shortening of the tube train.

  There is also a need for a jet device

  not requiring the use of expensive coaxial tubes.

  The invention aims precisely to meet these needs.

  More particularly, the invention relates to a jet field treatment device comprising a set of rods or tubes connected one after the other, a device for driving the set of rods or tubes in rotation and / or in translation mounted. on the upper part of said train, at least one ejection nozzle provided at the lower part of said train, at least one source of fluid under high pressure, and a conduit connecting the source of fluid under high pressure to said nozzle, characterized in that that: the driving device of the drill string or tubes imparts an alternating rotational movement to the latter, and the feed pipe consists of a pipe

  flexible connecting said source to said nozzle.

  The device of the invention will usually comprise one, two or three grout nozzles, plus possibly water nozzles. When two or three grout nozzles are present, they will usually be directed in different directions, at 1800 (case of two nozzles)

  or 1200 (three nozzles) from each other.

  Each flexible hose can feed a single nozzle or

  several nozzles via a distributor.

  The flexible pipe or hoses can be left free or held in contact with or near the outer surface of the drill string or tubes, for example by fixing them in loops integral with the drill string or tubes or by inserting them in recesses. planned on

the train of rods or tubes.

  In addition to the presence of flexible hoses, the device of the invention is characterized in that the drive device prints the train of rods or tubes an alternating rotational movement doubled, when desired, a translational movement L 'angle of rotation in one direction, then in the other depends on the number, the type,

  and the relative positioning of the ejection nozzles.

  For a device comprising a single grout ejection nozzle, the angle of rotation will be 360 (one complete revolution) in one direction, then in the other. For a device comprising two grout ejection nozzles oriented at 1800 l one of the other, the angle of rotation could be 1800 (one half-turn) in one direction, then in the other The all is that the whole ground surrounding the drilling o is arranged the device of the invention is treated during

of the alternating rotation cycle.

  In particular situations, for example in the vicinity of obstacles, the angle of rotation may be limited so as not to cover voluntarily the whole of the

field surrounding the borehole.

  In the device of the invention, the tube train no longer serves as a fluid supply duct and has only a mechanical function, namely to transmit to the nozzles the alternating and optionally translational rotation movement that it prints. As a result, the train no longer needs to be hollow and the hollow tube train can be replaced by a string of rods.

full, if desired.

  When it is therefore desired, for any reason, to shorten the string of rods or tubes, during the ascent of the latter, it is sufficient to remove the (s) stem (s) or upper tube (s) of said train this can easily be done without having to interrupt the fluid supply because it is provided by the flexible hoses. Any risk of obstruction

nozzles are thus avoided.

  Optionally but preferably, a reel can be provided for each of the hoses present to facilitate the descent of the jet device of the invention in the borehole and its recovery, thus avoiding the presence of flexible pipes scattered on the ground that could be dangerous because of the high pressure of the fluids conveyed. For the remainder, the structure and the implementation of the jet device of the invention are similar to those of the devices of the prior art and it therefore seems quite

  superfluous to describe them in detail.

  The following description, made with regard to the

  single figure attached, will make clear the present invention. The single figure is a schematic view of a

device according to the invention.

  In this figure is shown a train 1 of elementary tubes 2 connected to each other, at the bottom of which is fixed a terminal element 3 equipped with

  two ejection nozzles 4 and 5 and a drill bit 6.

  The train 1 can be rotated alternately and / or in translation by a driving device consisting of a hydraulic rotating head 7 enclosing the upper end of the train, itself mounted on a slide 8 substantially parallel to the tube train As shown in the figure, the tool 6 is of a larger diameter than the tube train to provide a free annular space between said train and the drill wall 9 made by the tool 6 in the field The nozzle 4 is connected by a flexible hose 10 to a source 11 of water under high pressure, while the nozzle 5 is connected by a flexible hose 12 to a source 13 of high pressure curable grout. As illustrated, reels 14 and 15, for the pipes 10 and 12, respectively, are provided on the surface, for winding or unwinding the flexible pipes in order to adjust their length to the needs and avoid that they drag on the ground, which in case of variations abrupt fluid pressure could cause dangerous "lashing". The train 1 of tubes no longer serving as fluid conduit (s), there is nothing to prevent it being shortened, as needed, during its ascent by removing the section of

  upper tube located above the head 7.

  It goes without saying that the described embodiment is only an example and that it could be modified, in particular by substitution of technical equivalents, without going out for

that of the scope of the invention.

Claims (2)

  A jet field treatment device comprising a train (1) of rods or tubes (2) connected one after the other, a driving device (7, 8) of the drill string or tubes in rotation and / or in translation mounted on the upper part of said train, at least one ejection nozzle (4, 5) provided at the lower part of said train, at least one source (11, 13) of fluid under high pressure, and a conduit connecting the source of fluid under high pressure at said nozzle, characterized in that: the driving device of the drill string or tubes impresses the latter with an alternating rotational movement, and the feed pipe consists of a pipe   flexible (10, 12) connecting said source to said nozzle.   2 Device according to claim 1, characterized in that it further comprises a reel (14, 15) associated with each hose.