Patent Publication Number: US-11384602-B2

Title: Boring assembly and associated boring method

Description:
The present invention relates to a boring assembly extending along a central axis. The invention also relates to a boring method. 
     In particular, the invention relates to boring in a civil engineering structure, in particular during the dismantlement of nuclear power plants. 
     BACKGROUND 
     The boring technique by hollow core drilling is known using a boring crown with the same diameter as the hole to be made in the structure. 
     However, this technique does not make it possible to produce inclined boreholes in a satisfactory manner. Indeed, at the end of boring, part of the boring crown still pierces the structure, while the rest of the crown protrudes outside the structure and can damage an equipment item located near the structure. 
     Also known from US20120067184 is a boring system for performing the hydrodemolition of concrete. The system comprises a boring head configured to supply a high-pressure jet of water and another boring head configured to supply an abrasive jet. 
     However, the handling of such a system is complicated. 
     SUMMARY 
     The aim of the present disclosure is then to propose a boring system making it possible to simplify handling thereof. 
     To that end, a boring assembly of the aforementioned type is provided, comprising:
         a boring head including:
           at least one first nozzle;   at least one second nozzle, the or each second nozzle being different from the or each first nozzle;   
           a first delivery device configured to deliver a jet of abrasive-free water at a pressure of between 2000 bar and 4000 bar to the at least one first nozzle;   a second delivery device configured to deliver a jet containing at least one abrasive material at a pressure of between 2000 bar and 6000 bar to the at least one second nozzle.       

     The handling of the boring assembly according to the present disclosure is simpler. Indeed, the boring using the boring assembly according the present disclosure does not require the alternating introduction of several boring heads, as is the case for the boring systems of the state of the art, which causes lost time and boring imprecisions. 
     According to other advantageous aspects of the present disclosure, the boring assembly comprises one or more of the following features, considered alone or according to any technical possible combinations:
         the boring head is cylindrical, and has a central head axis extending along the main axis;   the boring head has a diameter of between 200 mm and 1000 mm;   the boring assembly comprises a frame and a first rotational drive of the boring head relative to the frame around the central head axis;   the boring assembly comprises a body, a first cylindrical support having a first support central axis different from the central head axis and a second rotational drive of the first support relative to the body around the first support central axis, the at least one second nozzle being arranged on the first support, and the first support being connected to the body in rotation around the first support central axis;   the boring assembly comprises a second cylindrical support having a second support central axis different from the first support central axis, a third rotational drive of the second support relative to the first support around the second support central axis, the at least one first nozzle being arranged on the second support, and the second support being connected to the first support in rotation around the second support central axis;   the at least one second nozzle is configured to deliver an adjustable jet forming an angle between 0° and 45° relative to an axis passing through the second nozzle and parallel to the main axis;   the boring assembly comprises a rubble suction port, preferably arranged in the body and extending along the main axis;   the boring head comprises a lighting device and a camera, preferably supported by the first support;   the boring assembly comprises a fourth drive of the boring head in translation along the main axis relative to the frame;   the boring head has a front face substantially orthogonal to the main axis, the first nozzle and the second nozzle emerging on the front face.       

     The present disclosure also relates to a boring method using a boring assembly as described above, comprising the following steps:
         first delivery by the first delivery device of a jet of abrasive-free water at a pressure of between 2000 bar and 4000 bar to the at least one first nozzle;   second delivery by the second delivery device of a jet containing at least one abrasive material at a pressure of between 2000 bar and 6000 bar to the at least one second nozzle; the first delivery having taken place before, during and/or after the second delivery.       

     According to another advantageous aspect of the present disclosure, the boring method comprises the following steps:
         demolition of the concrete body by the jet of abrasive-free water delivered during the first delivery,   cutting of a metal element by the jet including at least one abrasive material delivered during the second delivery.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features and advantages of the present disclosure will emerge from the following detailed description, provided for information and non-limitingly, in reference to the appended figures, in which: 
         FIG. 1  is a schematic, partially sectional illustration of a boring assembly according to the present disclosure and a sectional view of a wall in which the boring assembly is introduced; 
         FIG. 2  is a perspective view of the boring head of the boring assembly of  FIG. 1 ; 
         FIG. 3  is a perspective view of the boring head of the boring assembly of  FIG. 1  during a step for delivering a jet of abrasive-free water; 
         FIG. 4  is a perspective view of the boring head of the boring assembly of  FIG. 1  during a step for delivering a jet of abrasive; 
         FIG. 5  is a perspective view of the boring head of the boring assembly of  FIG. 1  during a step for delivering a jet of abrasive oriented differently than in  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION 
     A boring assembly  10  is shown in  FIG. 1 . 
     The boring assembly  10  is configured to bore a wall  12 , in particular a wall  12  including mineral and metallic elements. In particular, the wall  12  is made from reinforced concrete made up of concrete  14  and metallic elements  16 . The metallic elements  16  are for example bars of iron or steel. 
     The boring assembly  10  extends along a main axis A-A′. 
     The boring assembly  10  comprises a boring head  18  including at least one first nozzle  20  and at least one second nozzle  22 , the or each second nozzle  22  being different from the or each first nozzle  20 . 
     As shown in  FIG. 1 , the boring assembly  10  comprises, in the example illustrated in the figures, a single first nozzle  20  and a single second nozzle  22 . 
     As visible in  FIG. 2 , the boring head  18  is cylindrical. The boring head  18  has a central head axis B-B′ extending along the main axis A-A′. 
     Advantageously, the boring head  18  has a diameter greater than 200 mm. In theory, the diameter has no upper limit. For applications to civil engineering, the boring head  18  has a diameter in particular of between 200 mm and 1000 mm, for example 280 mm. 
     The drilling head  18  has a front face  24 , the front face  24  being configured to be arranged across from the zone of the wall  12  to be bored. The front face  24  is substantially orthogonal to the central head axis B-B′. 
     The or each first nozzle  20  is configured to deliver a jet of fluid, in particular a jet of abrasive-free water. 
     An abrasive refers to a very hard material used to wear down other, softer materials. In particular, the abrasive material has a hardness greater than 6 mohs. An abrasive material is also characterized by its particle size, which is advantageously between 30 and 80 mesh. 
     The or each second nozzle  22  is configured to deliver a jet of fluid, in particular a jet including at least one abrasive material. The abrasive material is for example made up of garnet or almandine. Advantageously, the fluid is water in which the abrasive material is added. 
     The boring assembly  10  further comprises a first delivery device  26  and a second delivery device  28 . 
     The first delivery device  26  is configured to deliver the jet of abrasive-free water to the at least one first nozzle  20 . 
     In particular, the first delivery device  26  is configured to deliver the jet of water at a very high pressure in order to allow the boring by demolition by spalling of the concrete  14 . The very high pressure of the jet of water is between 2000 bar and 3000 bar. The flow rate associated with the jet of water is between 10 l·min −1  and 20 l·min −1 . 
     The boring assembly  10  advantageously comprises at least one third nozzle, not shown in the figures. 
     The first delivery device  26  is further configured to deliver a jet of abrasive-free water at low pressure to the at least one third nozzle in order to allow the discharge of the rubble from the zone of the wall  12  to be bored. In particular, the low pressure of the jet of water is between 2 bar and 10 bar. The flow rate associated with the jet of water is then between 20 l·min −1  and 100 l·min −1 . 
     The first delivery device  26  advantageously includes a tank comprising water, a pump and a pipe from the tank to the or each first nozzle  20 , not shown. 
     The second delivery device  28  is configured to deliver the jet including at least one abrasive material to the at least one second nozzle  22 . The pressure of the abrasive jet is between 2000 and 3000 bars. The flow rate associated with the abrasive jet is then between 200 and 500 g·min −1 . 
     The second delivery device  28  advantageously includes a tank comprising an abrasive material, a pump and a pipe from the tank to the or each second nozzle  22 , not shown. 
     Advantageously, the boring assembly  10  further comprises a frame  30  and a first drive  32 . 
     The frame  30  is a support located separately from the wall  12 . The frame  30  is stationary relative to the wall  12 . 
     The first drive  32  is configured to rotate the boring head  18  relative to the frame  30  around the central head axis B-B′. Advantageously, the amplitude of the rotation allowed by the first drive  26  is 360°. 
     The first drive  32  is of any appropriate type to allow said rotation. For example, the first drive  32  is a gear motor. 
     The boring assembly  10  also comprises a body  34 , a first support  36  and a second drive  38 . 
     The body  34  has a cylindrical shape, having the head axis B-B′ as central axis and the same diameter as the boring head  18 . The front face of the body  34  is parallel to and substantially at the same level as the front face  24  of the boring head  18 . 
     The first support  36  is cylindrical, having a first support central axis C-C′ different from the central head axis B-B′. The first support central axis C-C′ is for example substantially parallel to the central head axis B-B′. In a variant, the first support central axis C-C′ forms a non-nil angle, in particular between 0° and 45° with the central head axis B-B′. 
     As shown in  FIGS. 4 and 5 , the or each second nozzle  22  is configured to deliver an adjustable jet forming an angle between 0° and 80° relative to an axis F-F′ passing through said second nozzle  22  and parallel to the first support axis C-C′. 
     As shown in  FIG. 2 , the first support  36  is inserted into the body  34 . Advantageously, the first support  36  is connected in rotation to the body  34  around the first support central axis C-C′. The first support  36  emerges on the front face  24 . The first support front face  36  is for example parallel to and substantially at the same level as the front face  24  of the boring head  18 . 
     The or each second nozzle  22  is arranged on the first support  36  and, in particular, on the front face of the first support  36 . 
     The second drive  38  is configured to rotate the first support  36  relative to the body  34  around the first support central axis C-C′. Advantageously, the amplitude of the rotation allowed by the second drive  28  is 180°. 
     The second drive  38  is of any appropriate type to allow said rotation. For example, the second drive  38  is a gear motor. 
     By combination between the rotation allowed by the first drive  32  and the rotation allowed by the second drive  38 , the nozzles  20 ,  22  are able to follow any desired path on the front face  24 . 
     In one advantageous embodiment, the boring assembly  10  further comprises a second support  40  and a third drive  42 . 
     The second support  40  is cylindrical, having a second support central axis D-D′ different from the first support central axis C-C′. The second support central axis D-D′ is advantageously substantially parallel to the first support central axis C-C′. In a variant, the second support central axis D-D′ forms a non-nil angle with the first support axis C-C′. 
     As shown in  FIG. 3 , the or each first nozzle  20  is configured to deliver a jet forming an angle of between 0° and 45° relative to an axis E-E′ passing through said first nozzle  20  and parallel to the second support central axis D-D′. As shown in  FIG. 2 , the second support  40  is inserted into the first support  36 . Advantageously, the second support  40  is connected in rotation to the first support  36  around the second support central axis D-D′. The second support  40  emerges on the front face  24 . The front face of the second support  40  is parallel to and substantially at the same level as the front face  24  of the boring head  18 . 
     The or each first nozzle  20  is advantageously arranged on the second support  40 . In particular, the or each first nozzle  20  is located on the front face of the second support  40 . 
     The third drive  42  is configured to rotate the second support  40  relative to the first support  36  around the second support central axis D-D′. Advantageously, the amplitude of the rotation allowed by the third drive  42  is 360°. In particular, the third drive  42  is configured to allow a continuous rotation of the second support  40 , in particular at a rotation speed of between 100 and 600 rpm. −1 , for example 500 rpm −1 . 
     The third drive  42  is of any appropriate type to allow said rotation. For example, the third drive  42  is a gear motor. 
     In a variant, the third drive  42  is configured to allow the rotation of the second support  40  using the water flow circulating through the or each first nozzle  20 . 
     Advantageously, the boring assembly  10  comprises a suction port  44 . 
     The suction port  44  is arranged in the body  34  and the opening of the suction port  44  emerges on the front face  24 . The suction port  44  extends along the central head axis B-B′. 
     The suction port  44  is configured to suction, through the opening, rubble originating from the boring of the wall  12  as well as the fluids injected by the nozzles  20 ,  22  and to transport the rubble and the fluids from the front face  24  toward the outside of the wall  12 . 
     The suction port  44  is advantageously connected to a pump, not shown, configured to create a vacuum causing the suction and the transport of the rubble and fluids. 
     The boring assembly  10  advantageously comprises a lighting device  46  and a camera  48 . 
     The lighting device  46  is supported by the first support  36 , in particular on the front face of the first support  36 . The lighting device  46  is configured to illuminate the zone of the wall  12  to be bored. The lighting device  46  is advantageously made up of a plurality of bulbs arranged evenly in a circle around the camera  48 . 
     The camera  48  is supported by the first support  36 , in particular on the front face of the first support  36 . The camera  48  is configured to record and transmit to a screen, not shown and located outside the wall  12 , photographs or videos of the zone of the wall  12  to be bored. Advantageously, the camera  48  is configured to instantaneously transmit the acquired images to the screen in order to allow between control of the boring. 
     Advantageously, the lighting device  46  and the camera  48  are configured to go from a hidden configuration in which the lighting device  46  and the camera  48  are protected during the boring, to an active configuration in which the lighting device  46  and the camera  48  are able to illuminate and film the zone of the wall  12  to be bored. 
     Advantageously, the boring assembly  10  comprises at least one fourth nozzle, not shown in the figures, configured to supply a jet of compressed air on the lighting device  46  and the camera  48  in order to clean them and/or protect them from drippings during viewing steps after the boring steps. 
     The boring assembly  10  also comprises a fourth drive  50 . 
     The fourth drive  50  is configured to translate the boring head  18  along the central head axis B-B′ relative to the frame  30  and thus to make it possible to advance the boring of the wall  12  as the reinforced concrete is bored. 
     The fourth drive  50  is of any appropriate type to allow said translation. For example, the fourth drive  50  is a screw-nut system or a rack. 
     A boring method using the boring assembly  10  will now be described. 
     Initially, the boring assembly  10  is separated from the wall  12 . 
     The front face  24  of the boring head  18  is placed facing the wall  12  using the fourth drive  50 , which moves the boring head  18  in translation along the central head axis B-B′ relative to the frame  30 . 
     The first drive  32  and the second drive  38  place the boring head  18  and the first support  36  in the desired position facing the zone of the wall  12  to be bored. 
     If the zone of the wall  12  to be bored is made from concrete  14 , the boring method then comprises a step for first delivery by the first delivery device  26  of a jet of abrasive-free water at very high pressure to the or each first nozzle  20 . The concrete body  14  is then demolished by the very high-pressure jet of abrasive-free water, as shown in  FIG. 3 . Advantageously, a thickness of concrete  14  of between 40 mm and 60 mm is demolished during the first delivery step. 
     In particular, the third drive  42  rotates the or each first nozzle  20  around the second support central axis D-D′ relative to the first support  36 . The described jet of abrasive-free water then describes a cone around the second support central axis D-D′, as shown in  FIG. 3 , thus allowing an easier demolition of a thickness of concrete  14 . 
     By combination between the rotation done by the first drive  32  and the rotation done by the second drive  38 , the or each first nozzle  20  describes the desired path and makes it possible to remove a layer of the wall  12  made from concrete  14  along the diameter of the boring. 
     Additionally, the fourth drive  50  translates the boring head  18  by levels as the zone made from concrete  14  of the wall  12  is demolished. 
     Between each demolition level of the concrete  14 , the lighting device  46  and the camera  48  go from the hidden configuration to the active configuration. The lighting device  46  illuminates the zone to be bored and the camera  48  films and transmits the images of the zone of the wall  12  to be bored in order to control the boring and identify the metallic elements  16  that may be removed, in particular the steel or iron bars. 
     When the front face  24  is across from a metallic element  16 , the step for first delivery of the very high-pressure jet of abrasive-free water stops. 
     When the concrete zone  14  to be bored has been demolished, the first delivery device  26  delivers a low-pressure jet of abrasive-free water to the or each third nozzle in order to remove the rubble present across from the front face  24 . The suction port  44  suctions the water injected by the jet and the rubble and transports them outside the wall  12 . 
     The lighting device  46  and the camera  48  make it possible to identify the position and the shape of the metallic element  16 . 
     The first drive  32  and the second drive  38  place the boring head  18  and the first support  36  in the desired position facing the metallic element  16  to be destroyed. 
     The boring method then comprises a step for second delivery by the second delivery device  28  of a jet including at least one abrasive material to the or each second nozzle  22 . 
     The metallic element  16  is then cut by the abrasive jet, as shown in  FIGS. 4 and 5 . 
     The or each second nozzle  22  orients the abrasive jet as a function of the shape and the orientation of the metallic element  16 . 
     In particular, the or each second nozzle  22  makes it possible to cut a metallic element  16  oriented in substantially the same direction as the front face  24 , as shown in  FIG. 4 . 
     The or each second nozzle  22  also makes it possible to cut a metallic element  16  oriented substantially along the central head axis B-B′, as shown in  FIG. 5 , with a different orientation of the abrasive jet. 
     By combination between the rotation done by the first drive  32  and the rotation done by the second drive  38 , the or each second nozzle  22  describes the desired path and makes it possible to destroy the metallic element  16  precisely. 
     When the metallic element  16  has been demolished, the first delivery device  26  delivers a low-pressure jet of abrasive-free water to the or each third nozzle in order to remove the rubble present across from the front face  24 . The suction port  44  suctions the water injected by the jet and the pieces of iron and transports them outside the wall  12 . 
     In a variant, the suctioning is done during the demolition steps of the wall  12 , in order to remove the concrete rubble  14  and the cut metallic elements  16  continuously. 
     The terms “first delivery” and “second delivery” are used as simple terminology, but do not imply any relationship of temporal correlation between the steps of the boring method. The first delivery can thus be done before, during or after the second delivery. 
     Similarly to what has been described above, the boring method subsequently alternatively comprises first delivery steps to demolish the concrete zones  14  of the wall  12  and second delivery steps to destroy the metallic elements  16  present in the wall  12 . 
     The boring method therefore allows boring in a reinforced concrete wall  12  not requiring the alternating introduction of several boring heads and thus allowing easier handling of the boring assembly  10 . In addition to the time savings allowed by keeping the machine in place, the absence of round-trip is favorable to the reduced dispersion of rubble and effluents, which is a major point when working in a contaminated environment. 
     Additionally, the different drives  32 ,  38 ,  42 ,  50  and the orientation of the jets at the outlet of the nozzles  20 ,  22  make it possible to split the different elements  14  of the wall  12  into small enough residual rubble to be removed and transported by the suction port  44  using the stream of water injected by the or each third nozzle. In particular, the hydrodemolition allowed by the or each first nozzle  20  and the first delivery device  26  makes it possible to split the concrete  14  into pieces, the size of which is given by the mineral elements, such as stones, included in the composition of the concrete  14 . The precise cutting of the metal elements  16  using the controlled path of the or each second nozzle  22  makes it possible to split the metallic elements  16 , such as steel or iron bars, into small segments that are easily transportable by the suction port  44 . 
     The boring assembly  10  also makes it possible to perform an inclined boring without damaging the equipment items located near the wall  12 . 
     Inclined boring refers to boring done in a direction forming a non-nil angle with the axis normal to the outlet face, in particular an angle greater than 20° as shown in  FIG. 1 . The inclined boring is in particular advantageously done in a direction going from top to bottom. 
     Indeed, the metallic elements  16  are usually found in a civil engineering structure at least 50 mm inside the wall  12 . The alternating use of the nozzles  20 ,  22  and abrasive cutting being able to be done in a targeted manner on the metallic sections, the end of the borehole may emerge outside the wall  12  without using the abrasive cutting jet. The use of the abrasive-free jet alone makes it possible not to cut any metallic elements beyond the borehole, and in particular to bore any metallic wall to be preserved. 
     Additionally, the alternating use of the two delivery devices  22 ,  24  makes it possible to optimize the quantity of abrasives used, which makes it possible to reduce costs, as well as the ecological impact of the boring. 
     Lastly, the boring assembly  10  makes it possible to reduce the reaction forces of the jets, typically less than 10 daN, which lightens the structure and the necessary weight of the boring assembly  10 , unlike boring done with a pneumatic drill, for example, which leads to cracks in the structure. 
     The boring assembly  10  is in particular advantageously used to dismantle nuclear power plants having experienced accidents such as the Fukushima plant, for example. 
     The boring assembly  10  is also used to form openings in civil engineering structures when it is important to preserve the reinforcement bordering the opening so as to be able to subsequently remesh the structure when there is a new need.