Drilling assembly and device and method for forming a filling column in the soil

Abstract

Drilling arrangement (10) for forming a column of fill material in soil, comprising a drill (11) having a tube body (12) configured to communicate with a material feed container (13) for introducing fill material into a hollow core of the tube body (12), and a displacement drill bit (20) arranged at one axial end of the tube body, the latter having an outlet opening for the fill material from the hollow core of the tube body (12). The displacement drill bit (20) has a tip section (21) extending ahead of the drill in the feed direction and at least one extension section (22, 23) arranged behind the tip section (21) in the feed direction, the extension section being configured to act as a radial displacement body in a borehole, and each having a larger diameter than the tip section (21) and than the tube body (12), at least in the section to be received in the borehole.The drilling arrangement also includes a device (15) for supplying compressed air into the hollow core of the pipe body (12) in order to at least assist the conveyance of the material contained therein towards the outlet opening.

Description

[0001] The invention relates to a drilling arrangement for forming a column of fill material in the ground according to the preamble of claim 1, as well as a device for forming a column of fill material and a method for forming a column of fill material in the ground.

[0002] A filling pipe and a method for creating a column of fill material in the ground, comprising a pipe body which has an outlet opening for the fill material at its lower end, wherein the filling pipe is designed for ramming or vibrating into a soft, displaceable or cohesive soil and wherein a fill material is introduced into the cavity via the outlet opening at the lower end of the filling pipe, at least when the filling pipe is pulled out, and the fill material forms the column of fill material, are known from EP 3 135 819 B1 and DE 103 10 727 B4.

[0003] Materials such as concrete, lime, gravel, sand, crushed stone, or dry mortar can be injected into the ground through a hollow core in the pipe body. This process essentially creates vertical columns of fill material, which stabilize and reinforce the subsoil. These columns can extend down to a load-bearing soil layer capable of withstanding higher vertical forces.

[0004] The filling tube known from DE 103 10 727 B4 has a closure device with closing flaps on its underside. When the filling tube is driven in, the closure device seals the lower outlet opening for the filling material. When the filling tube is withdrawn, the closure device opens, allowing the filling material to trickle through the outlet opening into the resulting cavity in the ground, thus forming the column of filling material.

[0005] In contrast, the filling tube known from EP 3 135 819 B1 does not have a movable closing device; instead, the outlet opening, which is always open, is overlaid and partially covered by a displacement rib, but a passage for the filling material remains. A penetration point is formed on the underside of the displacement rib.

[0006] From DE 36 12 437 A1 a filling tube with a lost closure cap emerges, which closes the outlet opening and is separated from the filling tube when the filling tube is pulled out into the ground, releasing the outlet opening for the filling material, and remains in the ground with it.

[0007] US patent 3,270,511 discloses a method for creating a column of fill material in the ground, in which a filling pipe with multiple openings at its lower end is used. The openings are closed by sealing elements or one-way valves during insertion into the ground.

[0008] From EP 2 694 744 B1, a drilling arrangement for forming a columnar structure in a soil area is known, wherein the drilling arrangement comprises a first drill and a second drill, wherein the first drill comprises a tube and the second drill comprises a spiral and therefore acts as a conveying screw, wherein the first drill and the second drill are concentric, and wherein the second drill is configured to be arranged, at least partially, within the first drill such that, when rotating within the first drill, the second drill conveys a fill material to a lower axial outlet opening of the tube of the first drill and, when the drilling arrangement is simultaneously withdrawn, forms a granular columnar structure with a predominantly vertical compaction. The first drill has a first flared outer section on its feed or...direction of advance (the terms are used synonymously within the scope of this disclosure) front end, a second section and a third section, wherein the second section lies in the direction of advance between the first section and the third section and the first section has a larger diameter than the second section.

[0009] While the filling pipes of the type described above, which are driven into the ground by vibration, are relatively simple in design, the conveyance of the material along the length of the filling pipe relies solely on the effect of gravity and, if applicable, vibration from the vibrating device, and can therefore stall. In contrast, the drilling arrangement according to EP 2 694 744 B1 ensures the active conveyance of the material by means of the second drill bit. However, this design requires two separate rotary drive devices or at least two rotary drive outputs from a gearbox to drive the first and second drill bits. The arrangement is therefore relatively complex and prone to failure due to the use of the driven second drill bit or the active auger.

[0010] The invention is based on the TaskThe aim is to propose a drilling arrangement for forming a column of fill material in the ground, as well as a device for forming a column of fill material and a method for forming a column of fill material in the ground, which, with a comparatively simple design, enable reliable conveyance of the fill material and formation of the fill material column.

[0011] The problem is solved by a drilling arrangement with the features of claim 1, by a device containing the drilling arrangement with the features of claim 11, or by a method with the features of claim 13. Preferred embodiments of the invention are specified in the respective dependent claims.

[0012] The invention therefore proposes in particular a drilling arrangement for forming a column of fill material in a soil, comprising a drill bit having a pipe body configured to communicate with a material supply container in order to introduce fill material into a hollow core of the pipe body, and having a displacement drill bit arranged at one axial end of which a displacement drill bit is arranged, at which an outlet opening for the fill material from the hollow core of the pipe body opens, wherein the displacement drill bit has a tip section leading in the feed direction of the drill bit and at least one extension section arranged behind the tip section in the feed direction, which is configured to act as a radial displacement body in a borehole, and each has a larger diameter than the tip section and than the pipe body, at least in the section to be received in the borehole.The drilling arrangement further includes a device for supplying compressed air into the hollow core of the pipe body in order to at least assist the conveyance of the material contained therein towards the outlet opening.

[0013] A fundamental aspect of the invention is to provide a displacement section on the displacement drilling tool. This section forces soil material loosened by the drill bit radially outwards, preventing it from falling into a cavity formed by the drill bit. The presence of this displacement section causes radial compression of the loose soil material both when driving the drilling assembly into the ground and when withdrawing it from the borehole. This withdrawal can be continuous or incremental, particularly intermittent or reciprocating. As the filling material is injected into the cavity of the borehole below the displacement drilling tool, a column of fill material is formed in the soil.

[0014] Furthermore, the invention does not provide for an actively rotating auger or a second concentric drill bit within the pipe body to convey the fill material through the pipe body into the borehole. Instead, it is designed such that the pipe body, more precisely its hollow core, communicates with a material feed container to introduce fill material into the hollow core of the pipe body primarily by the force of gravity. The downward transport through the hollow core to the drill's exit opening also occurs primarily by gravity, but with the aid of a device for supplying compressed air into the hollow core of the pipe body. This device assists the conveyance of the fill material towards the exit opening by pressurizing the material in the conveying direction and by suspending the particles of the fill material, thus supporting its flow under the influence of gravity and preventing clumping.

[0015] The rotation and / or pulling motion of the drill bit out of the borehole and the associated vibrations, impulses and inertia also contribute to the transport of the fill material towards the exit opening and through it into the cavity of the borehole.

[0016] Preferably, the hollow core of the pipe body is open / free in a section between the material feed hopper and the outlet opening, in the sense that no drill bit or auger is rotatably mounted within it. However, this does not preclude, for example, the installation of fixed ribs, fins, or other projections on the inner wall of the pipe body that extend a short distance into the interior and serve to mix or transport the filling material without obstruction.

[0017] Preferably, the displacement drilling tool has at least two extension sections arranged in the feed direction behind the tip section, which are connected to each other by a connecting section arranged between the extension sections, and the at least two extension sections are preferably designed to act as radial displacement bodies in a borehole, and to each have a larger diameter than the tip section, than the connecting section and than the pipe body, at least in the section to be received in the borehole.

[0018] One advantage of this design of the displacement drill bit, with several displacement sections spaced axially apart, is that soil material loosened by the tip section and radially displaced by the first expansion or displacement section, but which subsequently falls back into the borehole cavity, is again radially displaced by the second (or subsequent) expansion or displacement section. The smaller-diameter connecting section between the expansion or displacement sections encourages loose soil material to fall back into the borehole for re-displacement. If only a single, possibly longer, displacement section were provided, it would merely prevent the loose soil material from falling back into the borehole, but would not achieve the same level of compaction as that achieved by renewed compaction after a certain period of relaxation.The provision of at least two expansion or displacement sections spaced apart in the longitudinal or axial direction causes radial compression of the loose soil material both when the drilling assembly is driven into the ground and when it is withdrawn from the borehole. This compression can occur continuously or incrementally, particularly intermittently or reciprocally, thereby forming the column of fill material in the soil below the displacement drill bit as it is pumped into the cavity of the borehole. The multiple displacement sections can preferably have the same maximum diameter or different diameters, with the diameter of the upper displacement section (i.e., the one furthest from the tip section) preferably being larger than that of the lower displacement section adjacent to the tip.

[0019] Preferably, the drilling arrangement within the device for supplying compressed air into the hollow core of the pipe body includes a closure mechanism designed to selectively connect and isolate the hollow core of the pipe body from the environment, in particular the material feed container. The closure mechanism, in the form of an airlock, is preferably arranged between an outlet of the material feed container and an inlet for the material into the hollow core of the pipe body. Selectively isolating the inlet for the material from the environment, in particular the material feed container, prevents the compressed air from escaping directly via the feed container, but instead forces the compressed air into the hollow core of the pipe body towards the outlet opening for the material. This creates a conveying pressure on the material introduced into the hollow core.

[0020] It is particularly preferred and advantageous if the closure mechanism is actuated so selectively that pressurized air is supplied essentially only when the hollow core of the tube is sealed off from the environment, in particular the material feed container. This reduces the loss of compressed air and, by alternately opening and closing the closure, preferably in conjunction with the supply of material from the material feed container, creates a pressure change on the material, which improves its conveying.

[0021] In a particularly advantageous variant, the compressed air itself or a selective supply thereof can be used to actuate the locking mechanism, for example to open it against a preload force in the closing direction.

[0022] Preferably, the pipe body, within the device for supplying compressed air into the hollow core of the pipe body, has channels that allow the compressed air to be directed towards the outlet opening for the filling material. This is achieved by allowing at least a portion of the compressed air to pass relatively unimpeded through the filling material in the hollow core in the feed direction and exit into the hollow core at one or more points along the axial direction of the pipe body. This can be accomplished, for example, by simple grooves or recesses in the inner wall of the pipe body, or by stable tubes or half-tubes inserted into the pipe body, which, in addition to transporting the air, also loosen the filling material to some extent during rotation.

[0023] Preferably, the drilling arrangement includes a material feed container at the other axial end (i.e., the upper end in the typical drilling orientation) for receiving the fill material, from which an outlet is connected to the hollow core of the pipe body. The container can be designed as a box-shaped, open-topped funnel that widens upwards, has a certain storage volume, and into which fill material can be supplied as needed via an external conveying device, for example, a hose conveyor or a bucket excavator.

[0024] Preferably, at least one expansion section of the displacement drill bit, but preferably several expansion sections, if present, have a conical transition section to the respective adjacent section of the tip section and / or the connecting section and / or the pipe body. The conical transition section progressively pushes the loose soil material outwards through a wedge effect during rotation and simultaneous feed, leading to radial compression and stabilization of the borehole walls.

[0025] Preferably, the tip section of the displacement drill tool has a raised auger section with a helix / pitch direction oriented in a direction of rotation towards the drilling motion. The auger section assists in loosening the soil material and causes a certain amount of conveyance against the feed direction towards the displacement areas. Furthermore, as is known from the previously described prior art of filling tubes, the tip section can have one or more closing flaps that close the outlet opening formed on the tip section, for example, at its axially leading end. These flaps can be opened for filling with the filling material when the drill assembly is withdrawn, or they can be detached as a "lost" component. The outlet opening can also be permanently open and / or partially covered by a displacement rib, as also previously described in connection with the prior art.

[0026] It is also preferred that at least one first of the expansion sections, which is preferably an expansion section arranged behind a second of the expansion sections in the feed direction, is provided with raised ribs which preferably run parallel to the axial direction of the tube body or inclined to the axial direction, and in the case of an inclined course have a twist direction / slope direction oriented opposite to the direction of rotation to the drilling.

[0027] Naturally, the second extension section, i.e., the one located immediately behind the pointed section in the feed direction, can also be provided with such an inclined or spirally raised rib. This rib (the singular is used here to also encompass multiple, discontinuous, and non-continuous spiral ribs) can have a helix / pitch direction oriented in the same direction as the direction of rotation during drilling, or a helix / pitch direction oriented opposite to the direction of rotation during drilling, in order to support the drilling action of the pointed section and to continue the conveying action of material away from the point or to transport material towards the point.

[0028] Preferably, the drilling assembly is designed to be coupled to a rotary drive for rotating the pipe body about its longitudinal axis and / or to a vibrator for the pipe body. The rotary drive is typically located in the region of the upper end of the drilling assembly and is a known prior art unit that is guided on the mast of a construction machine and drives the drilling assembly into the ground by rotating it in the feed direction, and then retracts it upwards along the mast. The rotary drive and, if present, the vibrator are externally powered and are adapted to the drilling assembly for the purposes of coupling and power transmission. The rotary drive and, if present, the vibrator cause the drill bit of the drilling assembly to be driven into the ground and, if necessary, assist in conveying the backfill material to the exit opening.

[0029] The invention also relates to a device, in particular a construction machine, for creating a column of fill material in a soil, with a mast which is held on a support base and along which a drilling arrangement according to the invention is movable and rotatable in an axial direction of the mast, and a rotary drive for rotating the drill of the drilling arrangement in order to drive it into the soil while displacing soil material.

[0030] The device (construction machine) can also be additionally equipped with a vibrator device for shaking the drilling arrangement, which supports the advancement of the drilling arrangement into the ground and the conveyance of the fill material.

[0031] The device according to the invention can be designed as a mobile, self-propelled construction machine, in which the support base is designed as a mobile carrier device with a chassis, in particular a crawler chassis, or can be designed as a stationary frame that is moved to the respective drilling point via another machine, for example a crane or cable excavator.

[0032] The invention also relates to a method for forming a column of fill material in soil, comprising the following steps: Arranging a device according to the invention for creating a column of fill material at a drilling point (i.e., self-propelled or via another machine); inserting the drilling arrangement into the ground by rotating and pressing it in, whereby a borehole is created in the ground by displacing soil material until the displacement drilling tool has reached a predetermined final depth; and introducing fill material from the material feed container via the hollow core of the pipe body and through the outlet opening on the drilling displacement tool into the borehole, while the drilling arrangement is continuously or stepwise, in particular intermittently or reciprocally, withdrawn from the borehole, thereby creating a column of fill material.While the filling material is poured into the cavity of the borehole below the displacement drill bit, forming the fill material column in the ground, the process involves supplying pressurized air to the hollow core of the drill assembly during the introduction of the fill material to at least assist the conveyance of the fill material contained therein towards the exit opening.

[0033] In the inventive method, by reciprocating the drill of the drilling arrangement to form the fill material column, i.e., by gradually pulling it out and repeatedly partially lowering it to compact the fill material introduced into the ground, a particularly dense and therefore stable fill material column can be produced in the ground, since both the soil material in the wall area of ​​the borehole is stabilized by being pressed or displaced outwards into the borehole wall, and the introduced fill material is compacted in the longitudinal direction of the borehole.

[0034] The displacement tool, specifically the at least one expansion or displacement section or the several expansion or displacement sections spaced apart in the longitudinal or axial direction, causes radial compression of the loose soil material both when driving the drilling arrangement into the ground and when withdrawing it from the borehole.

[0035] The transport of the filling material located in the pipe body towards the exit opening through the hollow core downwards to the exit opening of the drill is primarily driven by gravity, but is at least supported by the supply of compressed air into the hollow core of the pipe body, by pressurizing the filling material in the conveying direction, and by the air suspending the particles of the filling material, thus enabling continuous trickling under the influence of gravity and preventing clumping.

[0036] Preferably, the air is supplied under pressure, while the hollow core of the pipe body is selectively, preferably intermittently and further preferably alternately, sealed off from the environment, in particular the material supply container, with a supply of filling material into the pipe body.

[0037] Preferably, the filling material used in the process is a free-flowing or pourable material, in particular gravel, pebbles, sand and / or gypsum, which may in particular contain aggregates.

[0038] The invention is further explained below with reference to a preferred embodiment, which is schematically illustrated in the accompanying drawings. The drawings show: Fig. 1: a side view of an embodiment of a device according to the invention for creating a column of fill material, in which the drilling arrangement is attached; Fig. 2: an enlarged side view of the displacement drilling tool of the drilling arrangement of the device. Fig. 1 Fig. 3 an isolated representation of the drilling arrangement according to the invention, Fig. 4 an enlarged perspective view of a Fig. 3 The feed unit of the drilling assembly is marked by a circle, and Fig. 5 shows an enlarged front side view of the assembly. Fig. 4 shown feed unit.

[0039] In the Fig. 1A device 50 according to the invention for creating a column of fill material in the form of an exemplary selected construction machine is shown as a mobile, self-propelled carrier unit, which has a support base 51 with a chassis or undercarriage 52, in particular a tracked undercarriage. A superstructure 54 can be rotatably arranged on the tracked undercarriage 52. The drive units for the functional units of the device and an operator station 55 are arranged on the superstructure 54 in a known manner. A substantially vertical mast 56 can be adjustably, in particular tiltably, attached to the superstructure 54 via a linkage 58. In the illustrated embodiment, the mast 56 is designed as a mast. A support device 57 can be provided at the rear end of the device to selectively improve the support of the device in order to relieve the tracked undercarriage and to increase the support span.Such an additional support device can also be arranged on the underside of the mast 56 in its extension, as shown in . Fig. 1 indicated at 57'.

[0040] A rotary drive 60 is mounted along the mast 56 so as to be movable via an upper holding device 62. The rotary drive 60 is coupled to an upper end section of a drilling assembly 10 for forming a column of fill material in the ground, which forms a feed unit 14 for fill material and compressed air, such that the entire drilling assembly 10, and with it a drill bit 11 of the drilling assembly 10, is mounted so as to be movable and rotatable in an axial direction along the mast 56 and can be driven to rotate by the rotary drive 60 and simultaneously advanced in the axial direction in order to drive the drill bit 11 of the drilling assembly 10 into the ground while displacing soil material. The drill bit 11 of the drilling assembly 10 is additionally mounted so as to be rotatable and guided longitudinally via a further holding device 63 at the lower end of the mast 56.This further, lower holding device is preferably fixed stationary on the mast at least during the drilling process, while the upper holding device 62 effects the advance and retraction of the drill along the mast 56 via a cable pull mechanism of the construction machine.

[0041] The drill 11 has a pipe body 12 configured to communicate with a material feed container 13 for introducing a free-flowing, free-form, or pourable fill material (in particular gravel, crushed stone, sand, and / or gypsum, which may also contain further aggregates) into a hollow core of the pipe body 12. The material feed container 13 is shown schematically here as a box-shaped hopper open at the top and widened at the top. It is attached to the feed unit 14 and, via the feed unit, to the upper support device 62. The feed unit 13 moves along the mast together with the drill 11 and therefore synchronously with it, but is not rotated by the rotary drive 60. However, the material feed container 13 can also be arranged to be stationary or movable independently of the drill along the mast. In this case, it preferably communicates with the hollow core of the pipe body 12 via a pipe or hose.

[0042] The hollow core of the pipe body 12, i.e., its interior in the section between the material feed container 13 and the outlet opening, is open / free in the sense that no drill or auger is rotatably mounted within it. However, this does not preclude, for example, the possibility that webs, ribs, or other projections are permanently installed on the inner wall of the pipe body, extending a short distance into the interior and serving to mix or transport the filling material.

[0043] The pipe body 12 of the drill 11 can, as in Fig. 1 It is indicated that, to achieve a desired length in accordance with a borehole depth, several sub-segments 12a, 12b and 12c can be assembled, as is known in the prior art.

[0044] A displacement drilling tool 20 is arranged at the lower axial end of the drilling arrangement 10 or at the lower end of the pipe body 12 of the drill 11, at which an outlet opening for the filling material from the hollow core of the pipe body 12 opens.

[0045] The free-flowing, free-form, or pourable fill material is introduced from the fill material container 13 through the hollow liner of the pipe body 12 and through the (not shown) outlet opening at the lower end of the drill 11, particularly when the drill 11 is withdrawn from the ground, into the cavity formed by the drilling process. In this way, the cavity formed by the displacement drill 20 can be completely filled with fill material when the drill 11 is withdrawn, thereby creating a fill material column to stabilize and increase the load-bearing capacity of the soil.

[0046] The drilling arrangement 10 has a Figs. 4 and 5The device 15 shown is for supplying compressed air into the hollow core of the pipe body 12 in order to at least assist the conveyance of the material contained therein towards the outlet opening. This device 15 includes a compressed air connection 36 in the area of ​​the non-rotating section of the feed unit 14, through which compressed air is supplied from an external compressed air source, for example on the construction machine or a separate supply unit at the drilling site.

[0047] Below the compressed air connection 36 is a rotary feedthrough 35, which decouples the rotatable section of the feed unit 14 from the non-rotatable section thereof. Below the rotary feedthrough 35 is a transition 34 to the pipe body 12. This allows material to be fed from the material feed container 13, located in the non-rotatable section, into an inlet of the pipe body and thus into its hollow core, while the pipe body 12 can rotate relative to the non-rotatable section.

[0048] The device 15 for supplying compressed air to the hollow core of the pipe body 12 further comprises a closing mechanism 37, which is arranged in the area between the outlet of the material feed container 13 and the rotary feedthrough 35 (or an inlet for the material into the hollow core of the pipe body) and above the compressed air connection 36, and which is designed to selectively connect the hollow core of the pipe body 12 to the environment, in particular the material feed container 13, and to seal it off from it. In the sealed state, compressed air supplied to the hollow core cannot escape towards the material feed container 13, but is forced into the hollow core in the direction of the desired material flow.

[0049] The closure mechanism 37 can be designed as a mechanical orifice or gate element, for example in the form of a closure plate, which is actuated by an actuator to open and close and is arranged, for example, such that it interrupts or releases the passage of material from the outlet of the material feed container 13 and simultaneously provides a sufficient seal for the compressed air towards the feed container. However, the functions of shutting off the material and sealing or shutting off the compressed air can also be implemented as separate functional units.

[0050] In one variant (not shown), the compressed air itself, or a selective supply thereof, can be used to actuate the closure mechanism, for example, to open it against a preload force acting in a closing direction. In this variant, a change in the supply of filling material and the supply of compressed air into the hollow core of the pipe body is effected almost automatically.

[0051] Furthermore, the pipe body 12 can, for example, have channels that allow compressed air to be directed towards the outlet opening for the filling material and compressed air to be released at several points along the axial length of the pipe body 12 in order to improve the conveying of the material.

[0052] The displacement drilling tool 20, which is in Fig. 2The drill, shown in an enlarged view, has a tip section 21 extending ahead of the drill in the feed direction and at least one, in this example two, extension sections 22, 23 arranged behind the tip section 21 in the feed direction, which are connected to each other by a connecting section 24 arranged between the extension sections 22, 23. The extension section(s) 22, 23 are designed to act as radial displacement bodies in a borehole and each has a larger diameter than the tip section 21, the connecting section 24 and the pipe body 12, at least in the section to be received in the borehole.

[0053] At least one of the extension sections 22, 23 (preferably both) has (have) a conical transition section 30, 31; 32, 33 to the respective adjacent section of the tip section 21 and / or the connecting section 24 and / or the pipe body 12. The conicity of the transition sections in the axial direction causes, when the drill is moved in the axial direction, the application of a radial force outwards to soil material on the inner wall of the borehole, but also to loose soil material that has fallen into the borehole.

[0054] The tip section 21 has a worm section 25 raised outwards above a base body, which has a helix direction / pitch direction oriented in a rotational direction towards the drilling process. The outlet opening for the filling material can be opened axially at the lower axial end of the displacement drill tool 20, or only or additionally radially, or it can be closed by a flap and opened when the drill is withdrawn.

[0055] Furthermore, at least one first expansion section 23, which is preferably arranged behind a second expansion section 22 in the feed direction, also has radially projecting ribs 27 raised above a base body, which here run parallel to the axial direction of the tube body 12 and are distributed at regular intervals around the outer circumference. The ribs also continue over the adjacent conical transition sections 32, 33 and taper wedge-shaped towards their ends in the axial direction.

[0056] Alternatively, the ribs 27 can also run inclined to the axial direction, and in the case of an inclined course, have a twist direction / slope direction oriented in one / the direction of rotation opposite to the drilling direction.

[0057] In the embodiment of the displacement drill 20 shown here, the second extension section 22, located immediately behind the pointed section in the feed direction, also has such an inclined or spirally raised rib 26. This rib 26 (the singular is used here also to mean that the term encompasses several discontinuous ribs in a spiral shape) has a helix / pitch direction oriented in the direction of rotation corresponding to the drilling direction, but can also have a helix / pitch direction oriented opposite to the drilling direction in order either to continue and support the drilling and conveying action of the pointed section or to support the conveyance of material towards the drill tip. Here, too, the rib 26 continues over the adjacent conical transition sections 30, 31.

[0058] Finally, the connecting section 24 arranged between the extension sections 22, 23 can also have an inclined or spiral raised rib 28 with a smaller diameter than these, here with a helix direction / slope direction oriented in the direction of rotation for drilling, but alternatively also with a helix direction / slope direction oriented opposite to the direction of rotation for drilling.

[0059] In the embodiment of the drilling arrangement 10 shown here, as in Fig. 3As shown, in a transition area 38 between a lower end section of the pipe body 12 and the displacement drill bit 20, a further spiral rib 29 is formed on the outer circumference with an orientation or pitch that has a helix direction / pitch direction opposite to the direction of rotation for drilling. This rib 29 (which may also comprise several ribs) serves to transport material expelled from the borehole back into the borehole and, in conjunction with the downwardly adjacent expansion section, which has a larger outer diameter than the transition area, to displace the soil material radially into the borehole wall when the drill bit is withdrawn.

[0060] The entire drilling assembly 10 can be movably guided on the mast in its longitudinal direction and may also have a (not shown) vibrator device at the upper end of the drilling assembly 10, for example in the area of ​​the feed unit 14, for vibrating the drilling assembly 10. In this device, rotating unbalance units are used in a manner known per se to generate vibrations that are transmitted to the drilling assembly or the drill bit 11 thereof to support the advance in the feed direction. The vibrator device can also be referred to as a vibratory hammer.

[0061] By applying targeted vibrations via the vibrator device and moving the drilling assembly 10 downwards along the mast 56, the drilling assembly 10, with the displacement drill bit 20 arranged at its lower axial end, can be more easily driven into soft, displaceable soil while simultaneously rotating the drill bit of the drilling assembly in the feed direction via the rotary drive 60. The vibration also assists in conveying the fill material downwards through the pipe body 12.

[0062] As an alternative to a self-propelled carrier device, as shown and described, the device can also be designed as a stationary frame that does not have an undercarriage or chassis 52, but is mobile because it is erected at a drilling point with the help of a crane and fixed to the ground via anchoring points.

Claims

1. Drilling arrangement (10) for forming a column of fill material in soil, comprising a drill (11) having a pipe body (12) configured to communicate with a material feed container (13) to introduce fill material into a hollow core of the pipe body (12), and having a displacement drill tool (20) at one axial end of the pipe body, with an outlet opening for the fill material from the hollow core of the pipe body (12), wherein the displacement drill tool (20) has a tip section (21) extending ahead in the feed direction of the drill and at least one extension section (22, 23) arranged behind the tip section (21) in the feed direction, which is configured to act as a radial displacement body in a borehole, and each has a larger diameter than the tip section (21) and than the pipe body (12), at least in the section to be received in the borehole.and a device (15) for supplying compressed air into the hollow core of the pipe body (12) in order to at least assist the conveyance of the material contained therein towards the outlet opening.

2. Drilling arrangement (10) according to claim 1, characterized by that the displacement drilling tool (20) has at least two extension sections (22, 23) arranged in the feed direction behind the tip section (21), which are connected to each other by a connecting section (24) arranged between the extension sections (22, 23), and that which are designed to act as radial displacement bodies in a borehole, and each have a larger diameter than the tip section (21), the connecting section (24) and the pipe body (12), at least in the section to be received in the borehole.

3. Drilling arrangement (10) according to claim 1 or 2, characterized by that The device (15) for supplying compressed air into the hollow core of the pipe body (12) has a closure mechanism (37) which is designed to selectively connect and shut off the hollow core of the pipe body (12) from the environment, in particular the material supply container (13), wherein the closure mechanism (37) is preferably arranged between an outlet of the material supply container (13) and an inlet for the material into the hollow core of the pipe body (12).

4. Drilling arrangement (10) according to one of claims 1 to 3, characterized by that the pipe body (12) has channels which allow the compressed air to be directed towards the outlet opening for the filling material.

5. Drilling arrangement (10) according to one of claims 1 to 4, characterized by thatThe drilling arrangement (10) in the area of ​​the other axial end has the material feed container (13) for receiving the filling material, from which an outlet is connected to the hollow core of the pipe body (12).

6. Drilling arrangement (10) according to one of claims 1 to 5, characterized by that which has at least one extension section (22,23), preferably several extension sections, if present, a conical transition section (30,31;32,33) to the respective adjacent section of the tip section (21) and / or the connecting section (24) and / or the pipe body (12).

7. Drilling arrangement (10) according to one of claims 1 to 6, characterized by that the tip section (21) has a raised worm helix section (25) which has a helix direction / pitch direction oriented in a direction of rotation towards drilling.

8. Drilling arrangement (10) according to one of claims 2 to 7, each in combination with claim 2, characterized by that at least one first (23) of the expansion sections (22,23), which is preferably an expansion section arranged in the feed direction behind a second (22) of the expansion sections (22,23), is provided with raised ribs (27) which preferably run parallel to the axial direction of the tube body (12) or inclined to the axial direction, and in the case of an inclined course have a twist direction / slope direction oriented in one / the direction of rotation opposite to the drilling direction.

9. Drilling arrangement (10) according to one of claims 1 to 8, characterized by that the drilling arrangement (10) is designed to be coupled to a rotary drive (60) for rotating the pipe body (12) about its longitudinal axis and / or to a vibrator device for the pipe body (12).

10. Drilling arrangement (10) according to any one of claims 1 to 9, characterized by that the hollow core of the pipe body (12) is open / free in a section between the material feed container (13) and the outlet opening, in the sense that no drill and no auger are rotatably mounted in it.

11. Device (50), in particular construction machine, for creating a column of fill material in a soil, comprising a mast (56) which is held on a support base (51) and along which a drilling arrangement (10) according to one of claims 1 to 10 is movable and rotatable in an axial direction of the mast (56), and a rotary drive (60) for rotating the drill (11) of the drilling arrangement (10) in order to drive it into the soil while displacing soil material.

12. Device (50) for creating a column of filling material according to claim 11, characterized by thatthe support base (51) is designed as a mobile carrier device with a chassis or undercarriage (52), in particular a crawler chassis, or as a stationary frame.

13. Method for forming a column of fill material in a soil, comprising the steps of: arranging a device (50) for creating a column of fill material according to claim 11 or 12 at a drilling point; introducing the drilling arrangement (10) into the soil by rotating and pressing it in, whereby a borehole is created in the soil by displacing soil material until the displacement drilling tool (20) has reached a predetermined final depth;and the introduction of fill material from the material feed container (13) via the hollow core of the pipe body (12) and through the outlet opening on the drilling displacer tool (20) into the borehole, while the drilling arrangement (10) is continuously or stepwise, in particular intermittently or reciprocally, withdrawn from the borehole, thereby forming the fill material column in the ground, wherein, during the introduction of fill material, pressurized air is supplied into the hollow core of the pipe body (12) of the drilling arrangement (10) to at least assist the conveyance of the fill material contained therein towards the outlet opening.

14. Method for forming a column of fill material according to claim 13, characterized by thatThe air is supplied under pressure, while the hollow core of the pipe body (12) is selectively, preferably intermittently and further preferably alternately, sealed off from the environment, in particular the material supply container (13), with a supply of filling material into the pipe body (12).

15. Method for forming a column of fill material according to claim 13 or 14, characterized by that The fill material used is a flowable, pourable or free-flowing material, in particular gravel, pebbles, sand and / or gypsum, which may contain aggregates.

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