NON-CONTACT TYPE PILE CUTTING APPARATUS USING WATERJET AND CUTTING METHOD THEREOF

Abstract

The present disclosure relates to a non-contact type pile cutting apparatus using a waterjet, particularly to a pile cutting apparatus entering the inside for cutting a pile including: a body that has a pipe form and is put into an inside of the pile; a gripper unit that is provided at an outer side of the body and fixes the body to the pile when the pile cutting apparatus has reached a cutting position of the pile; a waterjet unit that is provided at one side of the body and fixed by the gripper unit, and then sprays an abrasive mixture in which an abrasive and a fluid are mixed, toward the pile in a high pressure; a rotation unit that rotates the waterjet unit around a central axis of the body; a feed line that feeds the abrasive mixture in which the fluid and the abrasive of a set ratio are mixed, to the waterjet unit from the outside; a feed unit that controls a feed pressure of the abrasive mixture fed through the feed line; and a nozzle driving unit that controls a position of the waterjet unit.

Description

BACKGROUND

Technical Field

The present disclosure relates to a non-contact type pile cutting apparatus using a waterjet and methods for operating and controlling the same.

Related Art

An offshore jacket structure is installed integrally with a pile penetrated into the seabed. Namely, the offshore jacket structure is built by seating jacket legs belonging to the lower structure of the offshore jacket structure on the seabed, inserting a jacket pile into a jacket leg so as to penetrate the lower part of the jacket pile into the seabed, fixing the jacket pile and the jacket leg by grouting between them, and filling the inside of the jacket pile with infilled concrete. At this time, when a hard support layer such as rock bed exists, following drilling, is inserted an anchor pile (pin pile), followed by grouting between the jacket pile and the anchor pile for fixation, and treating infilled concrete.

The demolition process of an existing offshore jacket structure includes demolishing the oil well or electrical facility connected to the jacket or seabed and then the topside facility of the offshore jacket structure, following by the remaining penetrated jacket piles.

It is required to remove the jacket pile installed on the seabed to a depth of 3-5 m from the seabed according to international standards.

When installing the jacket structure, the jacket pile inside the jacket leg is penetrated into the seabed, and then the inside of the pile is treated with infilled concrete. Since it is difficult to penetrate the jacket pile into the hard support layer by pile driving, it is general to drill the inside of the jacket pile and installing an anchor pile, followed by grouting between the anchor pile and the jacket pile and treating the rest with infilled concrete.

Further, a waterjet cutting apparatus is an ultraprecise processing apparatus that processes or cuts a workpiece by spraying high pressure water including an abrasive in the form of a particle thereto.

A waterjet or an abrasive waterjet system is used to cut a wide range of materials including stone, glass, ceramics and metal. In the typical waterjet system, high pressure water flows through a cutting head with a nozzle that directs a cutting jet to the workpiece. The waterjet system absorbs or feeds an abrasive medium into or to a high pressure waterjet, so as to form a high pressure abrasive waterjet. Then, the cutting head may be controllably moved across the workpiece so as to cutting the same as desired, or the workpiece may be controllably moved to beneath the waterjet or the abrasive waterjet. For example, a system for generating a high pressure waterjet such as TM 5 axis waterjet system manufactured by Flow International Corporation are currently available. Another example of Mach 4 waterjet system is shown and described in U.S. Pat. No. 5,643,058 of Flow, which is incorporated herein by reference in their entirety.

When applying the abrasive waterjet cutting system to cut penetration piles, it is difficult to determine as to whether seabed penetration piles are cut or not, whether the piles are penetrated through a waterjet or not, etc. Thus, there is a problem in monitoring the entire cutting process.

SUMMARY

Technical Problem

Therefore, the present disclosure is contrived to solve conventional problems as described above. According to the embodiment of the present disclosure, aimed is to provide a non-contact type pile cutting apparatus using a waterjet and methods for operating and controlling the same, wherein an abrasive and a fluid mixed at a set mixing ratio are fed in a mixture from the outside without any separate high pressure fluid and abrasive feed lines, allowing simplifying a feed line, and the pile cutting apparatus is furnished with a gripper unit, allowing facilitating fixation and release thereof inside a penetration pile.

According to the embodiment of the present disclosure, aimed is to provide a non-contact type pile cutting apparatus using a waterjet and methods for operating and controlling the same, wherein a rotation unit is controlled by identifying as to whether a penetration pile is penetrated by a waterjet or not, based on the data measured from a sound sensor and a vibration sensor during the cutting process, allowing remote-monitoring the cutting process without introducing any equipment such as a vision sensor.

Further, according to the embodiment of the present disclosure, aimed is to provide a non-contact type pile cutting apparatus using a waterjet and methods for operating and controlling the same, wherein a waterjet unit includes a guide portion, a nozzle moving unit and a nozzle setting unit, allowing precisely setting a nozzle portion prior to high pressure spaying of the waterjet.

Technical Solution

The present disclosure aims to achieve a non-contact type pile cutting apparatus using a waterjet, as a pile cutting apparatus entering the inside for cutting a pile, includes: a body that has a pipe form and is put into an inside of the pile; a gripper unit that is provided at an outer side of the body and fixes the body to the pile when the pile cutting apparatus has reached a cutting position of the pile; a waterjet unit that is provided at one side of the body and fixed by the gripper unit, and then sprays an abrasive mixture in which an abrasive and a fluid are mixed, toward the pile in a high pressure; a rotation unit that rotates the waterjet unit around a central axis of the body; a feed line that feeds the abrasive mixture in which the fluid and the abrasive of a set ratio are mixed, to the waterjet unit from the outside; a feed unit that controls a feed pressure of the abrasive mixture fed through the feed line; and a nozzle driving unit that controls a position of the waterjet unit.

The non-contact type pile cutting apparatus using a waterjet further includes: a casing which is connected to a lower part of the body, and in which an opening provided as a passage where a nozzle portion of the waterjet unit is protruded and inserted is formed, wherein the rotation unit is installed inside the casing, and the waterjet unit includes: a nozzle housing in which the nozzle portion that is connected to the feed line and sprays the abrasive mixture toward the pile in a high pressure is provided; a nozzle moving unit that moves the nozzle portion in a radial direction of the pile in the nozzle housing; and a guide portion which is provided at one side of the nozzle housing and is in contact in a state that the nozzle portion is being moved toward an inner surface of the pile by the nozzle moving unit, thus maintaining a distance between an end of the nozzle portion and the inner surface of the pile within a set range.

Further, non-contact type pile cutting apparatus using a waterjet further includes: a nozzle setting unit that performs rotation from an inner side of to an outer side of the casing of the nozzle housing, or reversely, wherein the guide portion includes: a rotation roller that is spaced apart from the nozzle portion at a predetermined interval in a length direction, and is provided at a position protruded toward an outer side of the nozzle portion; a tension unit that gives an elastic force to the rotation roller in an outer radial direction while allowing moving the rotation roller in a radial direction; and a tension detection portion that measures the elastic force of the tension unit in real time, and a control portion controls the nozzle moving unit so as to fix a radial direction position of the nozzle portion when the elastic force detected from the tension detection portion has reached a set range.

The gripper unit has a link structure and includes: a plurality of gripper members that is pressurized to and contacted with an inner side of the pile, when performing fixation to the body; and a link driving portion that moves the gripper member toward the pile when performing fixation, while moving the gripper member toward the body when performing release.

Further, a plurality of protrusions is installed on an outer surface of the gripper member. The link driving portion includes: a cylindrical shaped movable housing that moves up and downwardly while covering an outer surface of the body; and a driving link that is installed in a radial direction of the movable housing and drives the movable housing up and downwardly. The link structure includes: a connection link of which an inner end is hinge-connected with the driving link, and of which an outer end is hinge-connected to one side of the gripper member; an upper link of which an inner end is hinge-connected with an upper connection end installed to one side of an upper outer surface of the body, and of which an outer end is hinge-connected with an upper side of the gripper member; and a lower link of which an inner end is hinge-connected with an lower connection end installed to one side of a lower outer surface of the body, and of which an outer end is hinge-connected with a lower side of the gripper member. The gripper member is spread out toward the pile when the movable housing has been moved to a top part by the driving link, while being folded when the movable housing has been moved to a bottom part.

The non-contact type pile cutting apparatus using a waterjet further includes: a determination portion that includes a sound sensor provided at the nozzle housing and measuring sound data during work, and a vibration sensor measuring a vibration state of the nozzle housing, wherein the determination portion determines that the pile has been cut when a sound signal and a vibration value measured from the sound sensor and the vibration sensor are within set ranges.

Further, the non-contact type pile cutting apparatus using a waterjet further includes: database (DB) where stored are a pile thickness, ranges of sound data and vibration during cutting by the abrasive mixture according to materials, and ranges of sound data and vibration following penetration by the abrasive mixture, wherein the determination portion determines as to whether the pile has been cut or not, based on ranges of the sound data and vibration stored in the DB, and the control portion moves the nozzle housing in a circumferential direction up to a set angle by driving the rotation unit when the determination portion determines that the pile has been penetrated by a waterjet.

Advantageous Effects

According to a non-contact type pile cutting apparatus using a waterjet and methods for operating and controlling the same in accordance with the present disclosure, an abrasive and a fluid mixed at a set mixing ratio is fed in a mixture from the outside without any separate high pressure fluid and abrasive feed lines, allowing simplifying a feed line, and the pile cutting apparatus is furnished with a gripper unit, allowing facilitating fixation/release thereof inside a penetration pile.

According to a non-contact type pile cutting apparatus using a waterjet and methods for operating and controlling the same in accordance with the present disclosure, a rotation unit is controlled by identifying as to whether a penetration pile is penetrated by a waterjet or not, based on the data measured from a sound sensor and a vibration sensor during the cutting process, allowing remote-monitoring the cutting process without introducing any equipment such as a vision sensor.

Further, According to a non-contact type pile cutting apparatus using a waterjet and methods for operating and controlling the same in accordance with the present disclosure, a waterjet unit includes a guide portion, a nozzle moving unit and a nozzle setting unit, allowing precisely setting a nozzle portion prior to high pressure spaying of a waterjet.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a non-contact type pile cutting apparatus using a waterjet when performing release according to an embodiment of the present disclosure,

FIG. 2 is a side view of a non-contact type pile cutting apparatus using a waterjet when performing fixation according to an embodiment of the present disclosure,

FIG. 3 is a side view of a non-contact type pile cutting apparatus using a waterjet according to an embodiment of the present disclosure, following setting-up,

FIG. 4 is a front view of a non-contact type pile cutting apparatus using a waterjet according to an embodiment of the present disclosure, following setting-up,

FIG. 5 is a perspective view of a non-contact type pile cutting apparatus using a waterjet according to an embodiment of the present disclosure, following setting-up,

FIG. 6 is a side view of a non-contact type pile cutting apparatus using a waterjet when performing fixation when performing release according to another embodiment of the present disclosure,

FIG. 7 is a side view of a non-contact type pile cutting apparatus using a waterjet when performing fixation according to another embodiment of the present disclosure,

FIG. 8 is a block view showing signal flow of a control portion according to an embodiment of the present disclosure,

FIG. 9 is a flowchart of a non-contact type pile cutting method using a waterjet according to an embodiment of the present disclosure,

FIG. 10 is a cross-sectional view of a nozzle portion according to an embodiment of the present disclosure,

FIG. 11 is a cross-sectional view of a nozzle portion having a structure of a double pipe according to an embodiment of the present disclosure,

FIG. 12 is a structural view of a feed unit according to an embodiment of the present disclosure, and

FIG. 13 is a cross-sectional view of a cooling unit according to an embodiment of the present disclosure.

REFERENCE NUMBERS

• • 1: fee line 2: cooling unit 3: insulation frame 4: evaporator 5: cooling chamber
  • 10: body 20: gripper unit 21: gripper member 22: connection link
  • 23: upper link 24: lower link 25: movable housing 26: driving link 27: driving wheel
  • 30: casing 31: opening 40: nozzle setting unit 50: waterjet unit
  • 51: nozzle housing 52: nozzle moving unit 60: nozzle portion 61: entry area
  • 62: acceleration portion 63: focusing portion 64: exit chamfer 65: double pipe 66: compressed air outlet pipe
  • 70: guide portion 71: rotation roller 72: tension unit 73: tension detection portion 80: rotation unit
  • 90: feed unit 91: fluid tank 92: high pressure pump 93: abrasive tank 94: control valve
  • 95: mixing valve
  • 100: non-contact type pile cutting apparatus
  • 110: control portion 111: sound sensor 112: vibration sensor 113: DB 120: determination portion

DETAILED DESCRIPTION

Best Mode

Hereinafter, described are the structure and function of a non-contact type pile cutting apparatus using a waterjet according to an embodiment of the present disclosure, and methods for operating and controlling the pile cutting apparatus.

FIG. 1 is a side view of a non-contact type pile cutting apparatus using a waterjet when performing release according to an embodiment of the present disclosure. FIG. 2 is a side view of a non-contact type pile cutting apparatus using a waterjet when performing fixation according to an embodiment of the present disclosure.

Further, FIG. 3 is a side view of a non-contact type pile cutting apparatus using a waterjet according to an embodiment of the present disclosure, following setting-up, FIG. 4 is a front view of a non-contact type pile cutting apparatus using a waterjet according to an embodiment of the present disclosure, following setting-up, and FIG. 5 is a perspective view of a non-contact type pile cutting apparatus using a waterjet according to an embodiment of the present disclosure, following setting-up.

Further, FIG. 6 is a side view of a non-contact type pile cutting apparatus using a waterjet when performing fixation when performing release according to another embodiment of the present disclosure. FIG. 7 is a side view of a non-contact type pile cutting apparatus using a waterjet when performing fixation according to another embodiment of the present disclosure. Further, FIG. 8 is a block view showing signal flow of a control portion according to an embodiment of the present disclosure,

Further, FIG. 9 is a flowchart of a non-contact type pile cutting method using a waterjet according to an embodiment of the present disclosure.

A non-contact type pile cutting apparatus using a waterjet 100 according to an embodiment of the present disclosure may be configured to include a body 10, a gripper unit 20, a waterjet unit 50, a rotation unit 80, a fee line 1, a feed unit 90, a nozzle moving unit 52, a nozzle setting unit 40, etc., in general.

The body 10 is configured to be put into the inside of a penetration pile that is an object to be cut. The gripper unit 20 is provided at an outer side of the body 10, and configured to fix the body 10 to the penetration pile when the pile cutting apparatus 100 has reached to a cutting position of the pile and to release a fixation between the pile cutting apparatus and the penetration pile following cutting the pile.

Further, the waterjet unit 50 is configured to be provided at one side of a lower part of the body 10 and fixed by the gripper unit 20, and then to spray an abrasive mixture in which an abrasive and a fluid are mixed, toward the pile in a high pressure.

The rotation unit 80 is configured to rotate the waterjet unit 50 around a central axis of the body 10. The feed line 1 is configured to fee the abrasive mixture in which the fluid and the abrasive of a set ratio are mixed, to the waterjet unit 50 from the outside. The feed unit 90 is configured with a high pressure pump, etc. and to control a feed pressure of the abrasive mixture fed through the feed line 1.

Further, the nozzle moving unit 52 may be configured to fix the pile cutting apparatus by the gripper unit 20, and then to control a position of the waterjet 50.

A casing 30 is connected to the lower part of the body 90. In the casing 30, formed is an opening 31 provided as a passage where a nozzle portion 60 of the waterjet unit 50 is protruded and inserted. Further, the rotation unit 80 is installed inside the casing 30.

The waterjet unit 50 according to an embodiment of the present disclosure may be configured to include a nozzle housing 51, a nozzle moving unit 52, a guide portion 70, a nozzle setting unit 40, etc.

The nozzle housing 51 has the nozzle portion 60 that is connected to the feed line 1 and sprays the abrasive mixture toward the pile in a high pressure. The nozzle moving unit 52 is configured to move the nozzle portion 60 in a radial direction of the pile in the nozzle housing 51. The guide portion 70 is provided at one side of the nozzle housing 51, and is configured to be contact in contact in a state that the nozzle portion 60 is being moved toward an inner surface of the pile by nozzle moving unit 52, thus maintaining a distance between an end of the nozzle portion 60 and the inner surface of the pile within a set range.

FIG. 10 is a cross-sectional view of a nozzle portion 60 according to an embodiment of the present disclosure. As shown in FIG. 10, it is seen that the nozzle portion 60 according to the present disclosure may be configured to include an entry area 61, a conical shaped acceleration portion 62, a focusing portion 63 and an exit chamfer 64.

Preferably, the nozzle portion 60 is an acceleration nozzle that has an exit with a smaller diameter that that of the entry area 61. This allows converting the pressure inside a stream to an ultrahigh-speed stream. As forming an exit with a smaller diameter than that of a slurry stream on a nozzle entry, the effect thereof will be increased more.

Preferably, the nozzle portion 60 has the focusing portion 60 with a uniform diameter at an external end thereof, and the conical shaped acceleration portion 62 in which a diameter between the entry area 61 and the focusing portion 63 becomes decreased. This allows an output stream to achieve both desired speed and direction. A cone angle of the acceleration portion 62 does not exceed 27°. Preferably, the cone angle is about 13.5°. This provides a good balance between effective acceleration and a non-turbulent flow maintained. Preferably, the focusing portion 63 of the nozzle portion 60 has a ratio of length to diameter larger than 5:1, preferably a ratio of length to diameter larger than about 10:1. Further, it is preferable that the ratio of length to diameter is smaller than about 30:1.

The nozzle portion 60 is a mixing nozzle that has the acceleration nozzle 62 formed with a material harder than that of the focusing portion 63. The focusing portion 63 has a diameter that is the same as or smaller than the acceleration area with the smallest diameter so as to prevent introduction of turbulence. The exit includes the exit chamfer 64 with a cone angle of about 45°. This angle is sufficient to ensure flow separation in the exit.

FIG. 11 is a cross-sectional view of a nozzle portion having a structure of a double pipe 65 according to an embodiment of the present disclosure. As shown in FIG. 11, according to the present disclosure, the structure of the double pipe 65 may be configured to feed compressed air to an outer side of the nozzle portion, allowing a high pressure abrasive mixture to have a spiral current generation area.

In the structure, provided are an annular slit-typed compressed air outlet pipe 66 that feeds compressed air to a nozzle outlet and a point reduced inner wall surface that is toward the compressed air outlet pipe 66 from this slit, and a Coanda spiral air flow generation area is formed by the annular slit and the point reduced inner surface. Further, in an outlet portion of an inner pipe are placed an annular slit for feeding high pressure water and a point reduced inner wall surface that is toward an outlet, thereby forming a Coanda spiral current generation area of high pressure water.

According to an embodiment of the present disclosure, an abrasive mixture tank is provided. In the abrasive mixture tank, an abrasive mixture in which an abrasive and a fluid (water) are mixed at a set ratio is stored and a high pressure abrasive mixture is fed to the waterjet unit 50 through the feed line 1 by the feed unit 90.

FIG. 12 is a structural view of a feed unit according to an embodiment of the present disclosure. Further, as shown in FIG. 12, the feed unit 90 according to an embodiment of the present disclosure includes a fluid to be pumped, in a fluid tank 91, and the fluid flows to a high pressure pump 92 through a pipe. The high pressure pump 92 increases pressure. The part of the fluid flow from the high pressure pump 92 changes for flowing in the pipe and then flows to the inside of an flexible slurry control valve 94 and a friction type abrasive tank 93 including abrasive. In general, 10% fluidity is directed to the friction type abrasive tank 93 by a flowing pipe and the flexible slurry control valve 94. The fluidity may controls the fluid which the abrasive is used in to remain with stopping flowing. In an example of the estimated blocking time, the flow in a reference line may modulate an abrasive concentration so as to provide as 18% fluid. In the present disclosure, it is matter to maintain a diamond abrasive according to the concentrated fluid ratio, as much as the type of the diamond abrasive such as a container, Garnet, various kinds of silica, copper slag and synthetic materials. Alternatively, Corundum is used. The slurry of the fluid (i.e. water) and the abrasive is maintained at sufficient velocity sue to the volume of the fluid directed to the friction type abrasive tank 93. The abrasive is mixed with the fluid flow of the high pressure pump 92 by performing mixing through an abrasive mixing valve 95. The mixing valve 95 generates jet effect, hereby further including a Venturi that generates vacuum assistance in drawing water. With the described orientation, the abrasive mixture come out from the spray nozzle portion 60 may achieve ultrasonic velocity.

FIG. 13 is a cross-sectional view of a cooling unit according to an embodiment of the present disclosure. Further, according to an embodiment of the present disclosure, the cooling unit may be further provided at one side of the fee line 1. A cooling unit 2 may include an insulation frame 3, an evaporator 4, a cooling chamber 5, etc. Further, a water temperature control unit may be installed which maintains the temperature of an abrasive mixture by controlling a temperature sensor detecting the temperature of the abrasive mixture to be fed and a cooling capability of the cooling unit according to the temperature detected from the temperature sensor. Cutability is improved by using the feature that the viscosity depends on the temperature, for example, by increasing viscosity by cooling an ultrahigh pressure abrasive mixture with the cooling unit.

The nozzle setting unit 40 may be included, which rotates the nozzle housing from an inner side of to an outer side of the casing, or reversely. This nozzle setting unit 40 may be configured to include a link structure and a hydraulic cylinder for driving this link structure.

Further, the guide portion 70 may be configured to include a rotation roller 71 that is spaced apart from the nozzle portion 60 at a predetermined interval in a length direction, and is provided at a position protruded toward an outer side of the nozzle portion 60; a tension unit 72 that gives an elastic force to the rotation roller 71 in an outer radial direction while allowing moving the rotation roller 71 in a radial direction; and a tension detection portion 73 that measures the elastic force of the tension unit 72 in real time.

Therefore, a control portion 110 controls the nozzle moving unit 52 so as to fix a radial direction position of the nozzle portion 60 when the elastic force detected from the tension detection portion 73 has reached a set range.

Description of Embodiments

Hereinafter, described is a method for cutting a pile through a non-contact type pile cutting apparatus using a waterjet according to an embodiment of the present disclosure. Firstly, a pile cutting apparatus is put into the inside of a pile through a putting apparatus 51.

When the pile cutting apparatus has reached a cutting position of the pile S2, a control portion 110 operates a gripper unit 20 to fix the pile cutting apparatus 100 to the inside of the pile S3.

Hereinafter, described is the configuration of the gripper unit 20. The gripper unit 20 has a link structure, and is configured to include a plurality of gripper members 21 that is pressurized to and contacted with an inner side of the pile, when performing fixation to the body 10, and a link driving portion that moves the gripper member 21 toward the pile when performing fixation, while moving the gripper member 21 toward the body 10 when performing release.

More particularly, a plurality of protrusions is installed on the outer surface of the gripper member 21. The link driving portion includes a cylindrical shaped movable housing 25 that moves up and downwardly while covering an outer surface of the body 10 and a plurality of driving links 26 that is installed in a radial direction of the movable housing 25 and drives the movable housing 25 up and downwardly. Further, a driving wheel may be provided to the driving link 26, thus driving the movable housing 25 up and downwardly by driving of the driving wheel 27.

Further, the link structure is connected to the respective driving links 26, and is configured to include a connection link 22, an upper link 23 and a lower link 24. An inner end of the connection link 22 end is hinge-connected with the driving link 26 and an outer thereof is hinge-connected to one side of the gripper member 21. An inner end of the upper link 23 is hinge-connected with an upper connection end installed to one side of an upper outer surface of the body 10 and an outer end thereof is hinge-connected with an upper side of the gripper member 21. An inner end of the lower link 24 is hinge-connected with a lower connection end installed to one side of a lower outer surface of the body 10 and an outer end thereof is hinge-connected with a lower side of the gripper member 21.

Thus, it is seen that when the movable housing 25 has been moved to the top part by the driving link, as shown in FIG. 2 and FIG. 7, the gripper member 21 is spread out toward the pile. It is also seen that when the movable housing 25 has been moved to the bottom part, as shown in FIG. 1 and FIG. 6, the gripper member 21 is folded.

When the pile cutting apparatus 100 has been fixed to the pile by the gripper unit 20, a waterjet nozzle is protruded toward an outer side of the opening 31 by the nozzle setting unit 40. The nozzle portion 60 of the waterjet nozzle is moved close to the inner surface of the pile by the nozzle moving unit 52.

That is, the nozzle moving unit 52 moves the nozzle housing 51 provided with the nozzle portion 60 in a radical direction of the pile, and is in contact in a state that the nozzle portion is being moved toward an inner surface of the pile by the nozzle moving unit, thus maintaining a distance between an end of the nozzle portion and the inner surface of the pile within a set range S4. That is, as mentioned above, the guide portion 70 includes the rotation roller 71 that is provided at a position protruded toward the outer side of the nozzle portion 60, the tension unit 72 that gives an elastic force to the rotation roller 71 in an outer radial direction while allowing moving the rotation roller 71 in a radial direction, and the tension detection portion 73 that measures the elastic force of the tension unit 72 in real time. The control portion 110 controls the nozzle moving unit 52 so as to fix a radial direction position of the nozzle portion 60, when the elastic force detected from the tension detection portion has reached a set range.

The abrasive mixture in which a fluid and an abrasive of a set ratio are mixed is fed to the feed line 1 with the waterjet unit 50 from the outside by the feed unit 90 S5, and the abrasive mixture is sprayed toward the pile in a high pressure from the nozzle portion 60 of the waterjet unit 50, which is connected to the fee line 1 S6.

The rotation unit 80 rotates the waterjet unit 50 around a central axis of the body 10 to cut the pile.

Hereinafter, described is a method for controlling a cutting process by the waterjet unit 50 according to an embodiment of the present disclosure.

The embodiment of the present disclosure may be configured to include a sound sensor 111 provided to one side of the pile cutting apparatus 100 and measuring sound data during work, and a vibration sensor 112 measuring a vibration state of the nozzle housing 51.

A determination portion 120 determines that the pile has been penetrated when a sound signal and a vibration value measured from the sound sensor 111 and the vibration sensor 112 are within set ranges. That is, generated is a difference between a sound signal in a state of not cutting and a sound signal received following pile penetration, during a spraying process, and the determination portion 120 determined as to whether the pile has been penetrated or not, based thereon S7.

Further, in database (DB) 113, are stored a pile thickness, ranges of sound data and vibration during cutting by the abrasive mixture according to materials, and ranges of sound data and vibration following penetration by the abrasive mixture. The determination portion 120 determines as to whether the pile has been cut and penetrated or not as comparing the measured sound signal to the ranges of sound data and vibration stored in the DB 113.

Further, the control portion 110 drives the rotation unit 80 to move the nozzle housing 51 in a circumferential direction up to a set angle when the determination portion 120 determines that the pile has been penetrated by the waterjet S9. That is, following spraying, it is determined as to whether the pile is penetrated or not. When it is determined that the pile has been penetrated, the waterjet unit 50 is moved up to a certain angle. When a sound signal according to penetration is still received following the movement thereof, it is determined that pile cutting has been completed S8. When a sound signal in a range of non-penetration is received after the movement at a certain angle, the pile is cut and penetrated by driving the waterjet. This process is continued repeatedly until determining that the pile cutting has been completed.

When it is determined that the pile cutting has been completed, it is stopped to feed the abrasive mixture 510, and the fixation between the pile and the pile cutting apparatus 100 is released S11, followed by taking the pile cutting apparatus out S12.

Claims

1. A non-contact type pile cutting apparatus using a waterjet, as a pile cutting apparatus entering the inside for cutting a pile, comprising: a body that has a pipe form and is put into an inside of the pile;a gripper unit that is provided at an outer side of the body and fixes the body to the pile when the cutting apparatus has reached a cutting position of the pile;a waterjet unit that is provided at one side of the body and fixed by the gripper unit, and then sprays an abrasive mixture in which an abrasive and a fluid are mixed, toward the pile in a high pressure;a rotation unit that rotates the waterjet unit around a central axis of the body;a feed line that feeds the abrasive mixture in which the fluid and the abrasive of a set ratio are mixed, to the waterjet unit from the outside;a feed unit that controls a feed pressure of the abrasive mixture fed through the feed line; anda nozzle driving unit that controls a position of the waterjet unit.

2. The non-contact type pile cutting apparatus using a waterjet of claim 1, further comprising: a casing which is connected to a lower part of the body, and in which an opening provided as a passage where a nozzle portion of the waterjet unit is protruded and inserted is formed, whereinthe rotation unit is installed inside the casing, andthe waterjet unit comprises:a nozzle housing in which the nozzle portion that is connected to the feed line and sprays the abrasive mixture toward the pile in a high pressure is provided;a nozzle moving unit that moves the nozzle portion in a radial direction of the pile in the nozzle housing; anda guide portion which is provided at one side of the nozzle housing and is in contact in a state that the nozzle portion is being moved toward an inner surface of the pile by the nozzle moving unit, thus maintaining a distance between an end of the nozzle portion and the inner surface of the pile within a set range.

3. The non-contact type pile cutting apparatus using a waterjet of claim 2, further comprising: a nozzle setting unit that performs rotation from an inner side of to an outer side of the casing of the nozzle housing, or reversely, whereinthe guide portion comprises:a rotation roller that is spaced apart from the nozzle portion at a predetermined interval in a length direction, and is provided at a position protruded toward an outer side of the nozzle portion;a tension unit that gives an elastic force to the rotation roller in an outer radial direction while allowing moving the rotation roller in a radial direction; anda tension detection portion that measures the elastic force of the tension unit in real time, anda control portion controls the nozzle moving unit so as to fix a radial direction position of the nozzle portion when the elastic force detected from the tension detection portion has reached a set range.

4. The non-contact type pile cutting apparatus using a waterjet of claim 1, wherein the gripper unit has a link structure and comprises:a plurality of gripper members that is pressurized to and contacted with an inner side of the pile, when performing fixation to the body; anda link driving portion that moves the gripper member toward the pile during fixation, while moving the gripper member toward the body when performing release.

5. The non-contact type pile cutting apparatus using a waterjet of claim 4, wherein a plurality of protrusions is installed on an outer surface of the gripper member,the link driving portion comprises:a cylindrical shaped movable housing that moves up and downwardly while covering an outer surface of the body; anda driving link that is installed in a radial direction of the movable housing and drives the movable housing up and downwardly,the link structure comprises:a connection link of which an inner end is hinge-connected with the driving link, and of which an outer end is hinge-connected to one side of the gripper member;an upper link of which an inner end is hinge-connected with an upper connection end installed to one side of an upper outer surface of the body, and of which an outer end is hinge-connected with an upper side of the gripper member; anda lower link of which an inner end is hinge-connected with an lower connection end installed to one side of a lower outer surface of the body, and of which an outer end is hinge-connected with a lower side of the gripper member, andthe gripper member is spread out toward the pile when the movable housing has been moved to a top part by the driving link, while being folded when the movable housing has been moved to a bottom part.

6. The non-contact type pile cutting apparatus using a waterjet of claim 5, further comprising: a determination portion that comprises a sound sensor provided at the nozzle housing and measuring sound data during work, and a vibration sensor measuring a vibration state of the nozzle housing, whereinthe determination portion determines that the pile has been cut when a sound signal and a vibration value measured from the sound sensor and the vibration sensor are within set ranges.

7. The non-contact type pile cutting apparatus using a waterjet of claim 6, further comprising: database (DB) where stored are a pile thickness, ranges of sound data and vibration during cutting by the abrasive mixture according to materials, and ranges of sound data and vibration following penetration by the abrasive mixture, whereinthe determination portion determines as to whether the pile has been cut or not, based on ranges of the sound data and vibration stored in the DB, andthe control portion moves the nozzle housing in a circumferential direction up to a set angle by driving the rotation unit when the determination portion determines that the pile has been penetrated by a waterjet.

8. A method for cutting a pile through a non-contact type pile cutting apparatus using a waterjet comprising steps of: putting a pile cutting apparatus into an inside of a pile through a putting apparatus;fixing the pile cutting apparatus to the inside of the pile by operating a gripper unit by a control portion when the pile cutting apparatus has reached a cutting position of the pile;setting a waterjet to move a waterjet unit provided at one side of a body toward an inner surface of the pile through a nozzle driving unit;feeding an abrasive mixture in which a fluid and an abrasive of a set ratio are mixed, to a feed line with the waterjet unit from the outside by a feed unit, and spraying the abrasive mixture toward the pile in a high pressure from a nozzle portion of the waterjet unit, which is connected to the fee line; andcutting the pile by rotating the waterjet unit around a central axis of the body by a rotation unit.