JP2006028830A - Excavator for caisson - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an excavation technology of a caisson capable of easily controlling the settlement of the caisson and, at the same time, excavating the whole area of a cutting edge of the caisson. <P>SOLUTION: The excavator for the caisson comprises excavation bearing machines 30<SB>1</SB>to 30<SB>4</SB>arranged to a plurality of positions of the caisson 10, horizontal excavators 20<SB>1</SB>to 20<SB>5</SB>arranged to the lower surface of the cutting edge of the caisson 10 and horizontal controllers 50<SB>1</SB>to 50<SB>4</SB>arranged around the caisson on the ground side. The excavation bearing machines 30<SB>1</SB>to 30<SB>4</SB>are equipped with a vertical axis 31, a vane 32 and a motor 33. The horizontal controller 50<SB>1</SB>to 50<SB>4</SB>are equipped with a pair of cylinders 51 and 52 and a following means following the displacement of a rod of each cylinder. The excavator for the caisson is so constituted that the settlement of the caisson can be measured through the following means while alternately abutting each rod of a pair of cylinders 51 and 52 on a plurality of projected bodies 13 provided on the circumferential surface of the caisson 10. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a caisson excavator for excavating a direct base board of blade edges of various caissons.

Generally, in the caisson method, the caisson's own weight is used or a forcible loading load is applied to force a sharp blade edge into the ground, and the caisson method is excavated and laid.

The above-described conventional caisson laying technique has the following problems.
(1) Although the operator digs by hand or performs machine digging by a backhoe or the like near the caisson blade edge, the caisson blade edge tends to swell and the worker is exposed to danger.
(2) Due to the need to sink the caisson while maintaining high verticality, the amount of settlement per day is as small as several centimeters.
Therefore, it takes a long time for construction, which is a major factor that increases construction costs.
(3) When there is a variation in the amount of caisson sinking and there is a tilt, there is a problem that it takes a lot of time and a lot of cost for the correction. It is difficult to press-fit while keeping the caisson's exact verticality.
(4) The applicant arranges a plurality of self-propelled excavators directly under the caisson blade edge, and excavates the ground directly under the blade edge while reciprocating these excavators to sink the caisson. 11-172688 and JP-A-11-269890 have been proposed previously.
This invention is technically difficult to excavate to every corner of the caisson with an excavator that reciprocates linearly when the caisson presents a flat rectangle, and with the caisson's own weight in the case of soft ground There is a new problem that the amount of settlement tends to vary.

The present invention has been made to solve the above-described conventional problems, and an object thereof is to provide one of the following caisson excavation techniques.
(1) To provide caisson excavation technology that can easily control caisson settlement.
(2) To provide caisson excavation technology that can excavate the entire area of the caisson blade edge.

The caisson excavating apparatus according to the first invention of the present application is a caisson excavating apparatus for excavating a direct base plate of a caisson blade edge, and a plurality of excavator bearings are arranged vertically at a plurality of locations of the caisson, The excavator is composed of a vertical axis extending downward from the blade edge of the caisson, a blade integrally provided at a lower portion of the vertical axis, and a motor for rotating the vertical axis, and the blade serves as a drilling blade when rotating. In addition to functioning, it functions as a resistance member that contacts the ground when rotation stops and prevents caisson settlement.
A caisson excavator according to a second aspect of the invention is a caisson excavator for excavating a direct base plate of a caisson blade mouth, wherein a excavator and a caisson blade arranged vertically at a plurality of locations of the caisson. It comprises a horizontal excavator disposed on the lower surface of the mouth so as to be reciprocally movable along the blade edge, and the excavator bearing unit is provided integrally with a vertical axis extending downward from the blade edge of the caisson and a lower portion of the vertical axis. A blade that rotates on the vertical axis, and the blade functions as a digging blade when rotating, and also functions as a resistance member that contacts the ground when rotation stops and prevents caisson settlement. It is a feature.
A caisson excavator according to a third aspect of the invention is a caisson excavator for excavating a direct base plate of a caisson blade mouth, and a excavator bearing device arranged vertically at a plurality of locations of the caisson, and a caisson blade A horizontal excavator disposed on the lower surface of the mouth so as to be reciprocally movable along the blade edge, and a horizontal control device disposed around the caisson on the ground side. It consists of a vertical axis that extends, a blade integrally provided at the bottom of the vertical axis, and a motor that rotates the vertical axis. The blade functions as an excavating blade when rotating, and touches the ground when rotation stops. It functions as a resistance member that prevents the caisson from sinking.
The caisson excavator according to the fourth invention is the caisson excavator according to the second or third invention described above, wherein the blades of the excavator bearing are positioned relatively lower than the horizontal excavator, It is characterized by providing a difference.
The caisson excavator according to the fifth invention is the caisson excavator according to the third or fourth invention, wherein the horizontal control device includes a pair of cylinders that expand and contract with a pair of vertical fluid pressures, and each rod of each cylinder. The caisson sinks through the tracking means while the tracking means is provided to follow the displacement, and the rods of the pair of cylinders are alternately brought into contact with a plurality of protrusions provided on the outer peripheral surface of the caisson at a predetermined interval. It is characterized in that the quantity can be measured.

The present invention can obtain the following effects.
(1) Not only the excavation function but also the excavation bearing pressure machine that prevents the caisson from sinking can be easily controlled.
(2) In particular, by controlling the horizontal control device and the excavator bearing in combination, the amount of caisson settlement can be controlled easily and accurately.
(3) By providing a level difference between the two excavators of the horizontal excavator with the blades of the excavation bearing pressure machine, it is possible to excavate the ground immediately below the caisson blade edge safely and efficiently.
In particular, when the shape of the caisson blade has a square shape, there remains no excavation of the corner, and the entire surface of the blade can be excavated.

  Embodiments of the caisson excavator of the present invention will be described below with reference to the drawings.

<1> Outline of the Device FIG. 1 shows a plan view of a part of the caisson 10 and a longitudinal sectional view of FIG.
The caisson 10 includes a plurality of horizontal excavators 20 _{1 to} 20 ₅ disposed so as to be capable of reciprocating directly below the blade edge of the caisson 10, and a plurality of excavation pressure bearings 30 ₁ to 30 disposed vertically at a plurality of locations of the caisson 10. ₄ and.

<2> Caisson The caisson 10 is a known concrete box such as an open type or a bottomed type. The caisson 10 is sequentially extended to the upper part of the caisson 10 according to subsidence.
In this example, the case where the horizontal sectional shape of the caisson 10 is a quadrangle is shown. However, the shape of the caisson 10 includes a polygon, a circle, an ellipse, and the like.
Further, the conventional caisson is sharply formed so that the blade edge can be easily pressed into the ground. However, in the present invention, the lower end surface of the blade edge of the caisson 10 does not need to be sharp, and is formed as a thick flat surface.
Moreover, the discharge port 11 is formed in the lower part of the side surface of the caisson 10 as necessary. The discharge port 11 is for discharging excavated soil through the shaft 40 provided on the side of the caisson 10.

<3> Horizontal Excavator A plurality of self-propelled horizontal excavators 20 _{1 to} 20 ₅ are arranged on the lower surface of the blade edge of the caisson 10. As a rule, one horizontal excavator 20 _{1 to} 20 ₅ is arranged on each side of the caisson 10 and the two horizontal excavators 20 ₄ and 20 ₅ are arranged on the side where the discharge port 11 is exceptionally provided. To do.

The horizontal excavators 20 _{1 to} 20 ₅ have a common structure equipped with a traveling body provided with self-propelling means, a pair of horizontal screws provided parallel to the traveling body in parallel, and a rotational driving means for the horizontal screw. For example, the excavator disclosed in Japanese Patent Application Laid-Open Nos. 11-172688, 11-269890, and 2001-20293 previously proposed by the applicant can be applied.

The horizontal boring machine 20 ₁ to 20 _5, while drilling with cutting edge width of the caisson 10, the drilling unit can be discharged excavated soil to the inside of the caisson 10, engages the cutting edge of the caisson 10, the cutting edge lower surface Various excavators other than those described above can be applied as long as the excavator includes traveling means that reciprocates.
Further, the reciprocating movements and the moving distances of the horizontal excavators 20 _{1 to} 20 ₅ are configured to be individually controllable.

<4> Excavation Supporting Machine Each shelf 12 is provided so as to protrude inside the corner of the caisson 10, and the excavation supporting machines 30 ₁ to 30 ₄ are provided on each shelf 12. In addition to the function of rotating and excavating the corners of the blade edge of the caisson 10, the excavation bearing machines 30 ₁ to 30 ₄ obtain a reaction force on the ground immediately below the blade edge and actively prevent the caisson 10 from sinking. Have both.
Excavators having a ground support function have not existed so far, and the excavator bearings 30 ₁ to 30 ₄ are greatly useful for controlling the attitude of the caisson 10 during subsidence, as will be described later.

The excavation bearing machines 30 ₁ to 30 ₄ illustrated in FIGS. 1 and 2 will be described. The excavation bearing machines 30 ₁ to 30 ₄ are integrated with the vertical axis 31 extending downward from the blade edge of the caisson 10 and the lower part of the vertical axis 31. And a motor 33 that gives rotation to the vertical axis 31.

A vertical axis 31 is rotatably passed through the shelf 12 of the caisson 10.
A support shaft 31 having blades 32 extends below the shelf 12, and the blades 32 are disposed below the horizontal excavator 20.
As shown in FIGS. 3 and 4, the blade 32 is formed by radially cutting a disk, and providing a strip-shaped excavation bit 34 on the lower surface of the end of the remaining radiation blade 33. Use one that can be discharged upward through the notch space. The blade 32 may be a known screw blade having a short axial length.

In addition, the rotation of the blades 33 of the excavation bearing pressure machines 30 ₁ to 30 ₄ can be individually controlled, and the excavation function is exhibited while the blades 32 are rotating. It functions as a member (press-fit resistance member).

Next, the relationship of the excavation range between the horizontal excavators 20 _{1 to} 20 ₅ and the excavation pressure bearings 30 ₁ to 30 ₄ will be described.
As described above, the excavator bearings 30 ₁ to 30 ₄ are positioned relatively lower than the horizontal excavators 20 _{1 to} 20 ₅ .
Thus was formed a height difference on both drilling and avoids the horizontal boring machine 20 ₁ to 20 ₅ to interference (collision) with the drilling bearing capacity machines 30 ₁ to 30 ₄ when the reciprocating, horizontal This is because the excavation range of the excavator 20 is brought close to the corner of the caisson 10.
Figure 5 is a view of a part of corner portions of the caisson 10 from the cutting edge side, planar drilling ranges by excavating Bearing unit 30 ₁ shown in two-dot chain lines, horizontal drilling machines deployed on each side of the cutting edge The diameter of the blade 32 is set so as to overlap with a flat excavation range by the reciprocating movement of 20 ₁ and 20 ₂ . As a result, excavation over the entire length of the blade edge of the caisson 10 becomes possible.

[Action]
Next, the caisson settlement method will be described.

<1> Excavation As shown in FIG. 1, horizontal excavators 20 _{1 to} 20 ₅ are set on each side of the cutting edge of the caisson 10, and excavation pressure bearings 30 ₁ to 30 ₄ are set on the inner corners of the caisson 10. .
The horizontal excavators 20 _{1 to} 20 ₅ cooperate with the excavation pressure bearings 30 ₁ to 30 ₄ to excavate the cutting edge ground of the caisson 10.

Each horizontal excavator 20 _{1 to} 20 ₅ reciprocates along the straight part of the blade edge of the caisson 10 to excavate the straight base board with the blade width of the caisson 10 and discharge the excavated soil to the inside. Further, each excavation bearing machine 30 ₁ to 30 ₄ rotates and excavates just below the edge of the corner of the caisson 10.
Although the above-described horizontal excavators 20 _{1 to} 20 ₅ alone are likely to cause excavation residue at the corners of the caisson 10, the caisson can be provided by providing the excavation pressure bearings 30 ₁ to 30 ₄ with a height difference at the corners of the caisson 10. It becomes possible to excavate the direct base plate of the entire blade edge including 10 corners.

Excavation machines such as backhoes and bulldozers are installed in the caisson 10 in advance, and the excavated soil discharged from the horizontal excavators 20 _{1 to} 20 ₅ and the excavation pressure bearings 30 ₁ to 30 ₄ is located inside the caisson 10. The excavated soil is discharged to the ground through the shaft 40.
By repeating the above operations, the caisson 1 is sunk while evenly excavating the direct base plate of the blade edge 2.

<2> to equalize the horizontal control excavation of caissons, the horizontal excavator 20 ₁ to 20 ₅ which faces back and forth traveling at a constant speed, also the drilling Bearing unit 30 ₁ to 30 ₄ in the diagonal relationship etc It is good to drill at high speed.
Also, if there is a difference in altitude in the ground where the blade contacts, or if there are rocks and gravel, it will not be possible to excavate evenly.

In such a case, the entire horizontal displacement of the caisson 10 is detected by visual observation of the excavation state of each side of the caisson 10 or by using various sensors and displacement meters. When there is a variation in the total sinking of the caisson 10, in order to prevent further subsidence of the location where the caisson 10 is being excavated, the detected data is used to operate the excavator bearings 30 ₁ to 30 ₄ at predetermined positions. Is temporarily stopped. By stopping any _{one of the} excavation bearing pressure machines 30 ₁ to 30 ₄ , the blades 32 serve as a settlement brake to prevent the caisson 10 from sinking.

In the meantime, the excavation of the portion where the excavation is delayed is advanced to finely adjust the horizontality of the caisson 10. The location where the excavation is delayed is excavated by causing the horizontal excavators 20 _{1 to} 20 ₅ to self-propel or individually operating the excavation supporters 30 ₁ to 30 ₄ .
When the horizontal and vertical fine adjustments of the caisson 10 are completed, the operation of the excavation pressure bearings 30 ₁ to 30 _{4 at} the predetermined positions that have been stopped is resumed.

Although other embodiments will be described with reference to FIGS. 6 to 9, the same parts as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.
Also the corners of the caisson 10, and deploying the drilling Bearing unit 30 ₁ to 30 ₄ via a horizontal boring machine 20 ₁ to 20 ₅ and the difference in height, excavation caused by the reciprocating movement of each horizontal excavator 20 ₁ to 20 ₅ Since the excavation of the entire base plate including the corner portion of the caisson 10 by the rotary excavation by the excavation bearing pressure machines 30 ₁ to 30 ₄ is the same as that in the first embodiment, detailed description is omitted. To do.

This example is an embodiment in which the horizontality of the caisson 10 is controlled by additionally arranging horizontal control devices 50 ₁ to 50 ₄ .

<1> Caisson-side projections As shown in FIGS. 6 and 7, a plurality of projections 13 are provided on the outer peripheral surface of the caisson 10 at regular intervals. The protrusions 13 are arranged in parallel in two rows along the vertical direction, and the protrusions 13 in each row are arranged in a staggered manner with a half pitch shift in the vertical direction. These protrusions 13 are attached in advance when the caisson 10 is constructed.
The protrusion 13 is a rod-like or plate-like protrusion that can come into contact with the rods of the horizontal control devices 50 ₁ to 50 ₄ , and can be removed when the intended purpose is completed. It can be made of possible steel.

<2> Horizontal Control Device As shown in FIGS. 6 and 7, horizontal control devices 50 ₁ to 50 ₄ are arranged at a plurality of locations outside the caisson 10 on the ground side. In this example, a case where a total of four units are arranged opposite each other with respect to the planar quadrangular caisson 10 is shown, but the number of installed units and the arrangement position are appropriately selected.
Reference numeral 60 in the figure denotes a control unit that mainly performs operation control of the horizontal control devices 50 ₁ to 50 ₄ and operation control of the excavation bearing pressure machines 30 ₁ to 30 ₄ .

Since each of the horizontal control devices 50 ₁ to 50 ₄ has a common structure, one unit will be described with reference to FIG.
The horizontal control device 50 includes a pair of first and second cylinders 51 and 52 that expand and contract with a vertical fluid pressure, and tracking means that follows the displacement of the rods 51a and 52a of the cylinders 51 and 52. .

[A pair of cylinders]
A discharge path 53 and a reflux path 54 are connected between the upper and lower portions of the first and second cylinders 51 and 52, respectively, so that the fluid in the pair of cylinders can be circulated and transferred to each other. . When either one of the rods 51a and 52a contracts, the other one of the rods 51a and 52a expands using the contraction force. Since a pump is unnecessary, it becomes a simple structure.
The first and second cylinders 51 and 52 are not members for supporting the total weight of the caisson 10, but are members for following the sinking of the caisson 10 via the protrusions 13 to the last.

An opening / closing valve 55 is interposed in the discharge passage 53.
By opening the on-off valve 55, a circulation flow path is formed between the first and second cylinders 51, 52, allowing the rods 51a, 52a to freely expand and contract, and closing the valve to close the circulation flow path. It shuts off and forcibly stops the expansion and contraction of both rods 51a and 52a.
Accordingly, the on-off valve 55 is controlled to open at least when the rod 51a, 52a of the first or second cylinder 51, 52 is lowered, and to close at other times to close the flow path. The
As the on-off valve 55, an electromagnetic valve that can be remotely controlled by the control unit 60 and various control valves similar thereto are applied.

[Tracking means]
The tracking means is a device that is provided in each of the first cylinder 51 and the second cylinder 52, and individually follows the rods 51a and 52a as they are raised and lowered.
The tracking means includes a pair of feed bolts 70, 70 erected in parallel with the cylinders 51, 52, a lift body 71 that is screwed up and down with each feed bolt 70, a sensor 72 provided on each lift body 71, A servo motor 73 that rotates the feed bolt 70 and a rotation transmission mechanism 74 that transmits the rotation of the motor 73 to both the feed bolts 70 and 70 are configured.

[Elevator and feed bolt]
A guide rod 75 erected in parallel with the feed bolt 70 passes through each elevating body 71 and regulates the tilting and lateral shaking of the elevating body 71.
The pair of elevating bodies 71, 71 can be screw-fed in different directions on the feed bolts 70, 70. That is, when one lifting body 71 of the pair of lifting bodies 71, 71 descends, the other lifting body 71 rises by the same distance as the descending amount, and in the opposite case, the opposite movement is performed. The minimum feed amount is obtained by the thread pitch of the feed bolt 70.
In order to screw-feed the pair of elevating bodies 71 and 71 in different directions, a combination of the direction of forming the male screw of each feed bolt 70 and the direction of rotation of each feed bolt 70 is appropriately selected.

[Sensor]
The sensor 72 is a sensor for detecting the elevation of one of the rods 51a and 52a of the cylinders 51 and 52. For example, as shown in the figure, a limit switch or a pressure sensor that does not operate unless a certain level of pressure is applied is used. The first and second cylinders 51 and 52 are arranged at positions where they can abut against a part of the rods 51a and 52a.
In this example, a case is shown in which a limit switch sensor 72 is disposed so as to be able to contact the lower surfaces of the upper ends of the rods 51a and 52a.

[Rotation transmission mechanism]
The rotation transmission mechanism 74 is a gear transmission mechanism or a belt transmission mechanism for transmitting the rotation of the servo motor 73 to the feed bolts 70 and 70.

[Servomotor]
In this example, a servo motor 73 is used as means for imparting rotation to the feed bolts 70 and 70. This is to accurately control the lifting and lowering of the lifting body 71 in millimeter units (preferably 1 mm to 2 mm).
The servo motor 73 is controlled to rotate and stop based on a control command from the control unit 60.
The rotation direction of the servo motor 73 is switched depending on whether the sensing object to be contracted is the first or second cylinder 51 or 52.

[Control unit]
Control targets of the control unit 60 are at least the motors 33 of the excavator bearings 30 ₁ to 30 ₄ shown in FIG. 6, the servo motors 73 and the on-off valves 55 of the horizontal control devices 50 ₁ to 50 ₄ , as necessary. The control unit 60 may control the operations of the horizontal excavators 20 _{1 to} 20 ₅ .

The control unit 60 individually controls the operation of the on-off valve 55 of each of the horizontal control devices 50 ₁ to 50 ₄ and the operation of the servo motor 73 individually to set the settling amount of the caisson 10 as a whole, and a preset settling amount setting range. In this way, repeated measurement is performed to monitor excessive subsidence, and when variations occur in the amount of subsidence, each part is corrected and controlled.

The control unit 60 controls the open / close valve 55 of each of the horizontal control devices 50 ₁ to 50 ₄ and the servo motor 73 as follows.

(I) With respect to the on-off valve 55 When the switch of the pair of left and right sensors 72, 72 is a combination of on and off, the valve is opened.
When the switches of the pair of left and right sensors 72, 72 are both turned on, the valve is closed.

(Ii) Servo motor 73 When the switch of the pair of left and right sensors 72, 72 is a combination of on and off, operation control is performed.
When the switches of the pair of left and right sensors 72, 72 are both turned on, control is performed to stop the operation.

The control unit 60 not only controls individually each horizontal controller 50 _{1-50 4} as described above, for controlling the horizontal size and vertical size of the entire caisson 10, a plurality of drill Bearing unit 30 ₁ The control of the 30 ₄ motor 33 is performed as follows.
(I) When the amount of subsidence of the caisson 10 varies more than a predetermined value through the horizontal control devices 50 ₁ to 50 ₄ , the operation of the motor 33 of any one of the excavation pressure bearings 30 ₁ to 30 ₄ is stopped. To control.
(Ii) Control is performed so that the operation of the motors 33 of all the excavation bearing pressure machines 30 ₁ to 30 ₄ is resumed when the amount of settlement of the horizontal control devices 50 ₁ to 50 ₄ is equal.

<3> Operation of One Horizontal Control Device The operation of one horizontal control device 50 will be described with reference to FIG.
As the caisson 10 sinks, for example, the lowermost protrusion 13 in the left row contacts the upper end of the rod 51a of the left first cylinder 51 as shown in the figure, so that the fluid pressure causes the right second cylinder 52 to move. The rod 52a is pushed down, and at the same time, the left and right lifting bodies 71 track the lifting displacement of the rods 51a and 51b.

  This will be described in detail. When the switch on the left sensor 72 is turned on by contacting the left rod 51a, the opening / closing valve 55 of the discharge passage 53 is opened through the control unit 60, and the first and second valves are opened. A circulation flow path is formed between the cylinders 51 and 52, and at the same time, the servo motor 73 rotates in a predetermined direction to rotate the pair of left and right feed bolts 70 and 70.

Since the on-off valve 55 is opened to allow fluid movement in the first cylinder 51 and the second cylinder 52, the left rod 51a continues to descend while contacting the left row of protrusions 13, and the right The rod 52a of the second cylinder 52 continues to rise toward the lowest protrusion 13 in the right column.
As the servo motor 73 rotates, the left elevating body 71 is screwed to the left feed bolt 70 and descends. Similarly, the right elevating body 71 is raised by being screwed to the right feed bolt 70. In this way, the left and right lifting bodies 71, 71 move up and down following the lifting of the left and right rods 51a and 52a.

As described above, the control unit 60 measures the amount of caisson settlement within a preset range. Therefore, the sinking of the caisson 10 accompanying the contraction of the first cylinder 51 is measured in the same manner. The amount of settlement can be easily obtained from the rotational speed of the servo motor 73 based on the known screw pitch of the feed bolt 70.
The reason why the caisson sinking amount is monitored within a predetermined range is to continuously compare the sinking amount relative to other horizontal control devices 50 in a short time.

  As shown in FIG. 9, the rod 52a of the right second cylinder 52 is in contact with the lowest protrusion 13 in the right row, and the right sensor 72 is switched on (the left and right sensors 72, 72 are on). When switching to, the on-off valve 55 is closed, and at the same time, the operation of the servo motor 73 is stopped, whereby the operation of the tracking means is completed.

When the rod 51a of the left first cylinder 51 has been contracted for one stroke, the lowermost protrusion 13 in the left column indicated by the broken line in FIG. 9 is removed. As a result, the sensor 72 on the left first cylinder 51 side is turned off.
As a result, since the switch of the left sensor 72 is off and the switch of the right sensor 72 is on, the on-off valve 55 opens, and at the same time, the servo motor 73 rotates in the direction opposite to the aforementioned direction. To do.
Accordingly, as indicated by the arrow in FIG. 9, the second cylinder 52 is contracted and the first cylinder 51 is extended in accordance with the caisson 10 sinking. The left and right lifting bodies 71 and 71 move up and down following the expansion and contraction of the cylinders 51 and 52.

As described above, the caisson 10 sinks by repeatedly performing the steps of alternately performing contraction and extension operations by the left and right cylinders 51 and 52 and the step of alternately removing the lowest protrusions 13 of the left and right rows. taking measurement.

<4> Control of a plurality of horizontal control devices The above-described settlement measurement of the caisson 10 is performed at a plurality of points where the horizontal control devices 50 ₁ to 50 ₄ shown in FIG. 6 are installed.
When variation occurs in the amount of subsidence measured by each of the horizontal control devices 50 ₁ to 50 ₄ , the control unit 60 controls the motors 33 of the plurality of excavation bearing pressure machines 30 ₁ to 30 ₄ as follows.

When the predetermined amount of subsidence is reached earliest among the horizontal control devices 50 ₁ to 50 ₄ , it is determined that the range is pre-settled compared to other parts, and any of the level control devices 50 ₁ to 50 ₄ is closest to this range. The operation of the motor 33 of the excavation bearing pressure machines 30 ₁ to 30 ₄ is stopped. As a result, the blades 32 that have stopped rotating come into contact with the ground and resist the caisson 10 from sinking.

During this time, the excavation is continued in the range where the excavation is delayed by the horizontal excavator 20 and the remaining horizontal control devices 50 ₁ to 50 ₄ . During this time, any of the excavator bearings 30 ₁ to 30 ₄ described above waits while stopping until excavation catches up.

When all of the horizontal control devices 50 ₁ to 50 ₄ have settled down, the operation of any one of the excavator bearing pressures 30 ₁ to 30 ₄ that has been stopped is resumed.
As described above, the check of variation in the amount of subsidence of the caisson 10 and the correction of variation are repeatedly performed within a preset subsidence range, so that the caisson 10 can be subsidized while maintaining high levelness and verticality.

In some cases, the horizontal excavator 20 may be omitted, and the excavator directly below the blade edge of the caisson 10 may be excavated with only the excavator support 30.

It is explanatory drawing of Example 1 which concerns on invention, Comprising: The top view of the caisson which fractured | ruptured one part Sectional view of II-II in FIG. Top view of excavator bearing blades Sectional view of IV-IV in Fig. 3 Partial enlarged view of caisson corner viewed from ground side It is explanatory drawing of Example 2 which concerns on invention, Comprising: The top view of the caisson which fractured | ruptured one part Sectional view of VII-VII in FIG. Model diagram of horizontal control device when first cylinder contracts Model diagram of horizontal control device when second cylinder contracts

Explanation of symbols

10 ... Caisson 11 ... Caisson outlet 12 ... Caisson shelf 13 ... Protrusions 20 _{1 to} 20 ₅ Horizontal excavators 30 ₁ to 30 ₄ Excavator 31... Vertical axis 32... Blade 33... Radiation blade 34 ... Excavation bit 40 ... Vertical shafts 50, 50 ₁ to 50 ₄ ... Horizontal control device 51 ······· First cylinder 51a ··· Rod 52 ······· Second cylinder 52a ··· Rod 53 ··· Discharge passage 54 ··· Recirculation passage 55 ··· Opening and closing valve 60 ··· Control units 70, 71 ... Feed bolts 71, 71 ... Lifting bodies 72, 72 ... Sensor 73 ... Servo motor 74 ... Rotation transmission mechanism 75 ... Guide rod

Claims (5)

A caisson excavator for excavating a direct base of a caisson blade,
A plurality of excavator bearings are arranged vertically at multiple locations in the caisson,
The excavator bearing is a vertical axis extending downward from the edge of the caisson;
A blade integrally provided at the bottom of the vertical axis;
A motor that gives rotation to the vertical axis,
The blade functions as an excavating blade during rotation, and functions as a resistance member that contacts the ground when rotation stops and prevents the caisson from sinking.
Caisson drilling rig. A caisson excavator for excavating a direct base of a caisson blade,
Excavator bearings arranged vertically in several locations of the caisson;
It consists of a horizontal excavator arranged on the lower surface of the blade of the caisson so as to be able to reciprocate along the blade,
The excavator bearing is a vertical axis extending downward from the edge of the caisson;
A blade integrally provided at the bottom of the vertical axis;
A motor that gives rotation to the vertical axis,
The blade functions as an excavating blade during rotation, and functions as a resistance member that contacts the ground when rotation stops and prevents the caisson from sinking.
Caisson drilling rig. A caisson excavator for excavating a direct base of a caisson blade,
Excavator bearings arranged vertically in several locations of the caisson;
A horizontal excavator disposed on the lower surface of the blade of the caisson so as to be reciprocally movable along the blade;
It consists of a horizontal control device placed around the ground caisson,
The excavator bearing is a vertical axis extending downward from the edge of the caisson;
A blade integrally provided at the bottom of the vertical axis;
A motor that gives rotation to the vertical axis,
The blade functions as an excavating blade during rotation, and functions as a resistance member that contacts the ground when rotation stops and prevents the caisson from sinking.
Caisson drilling rig.   4. The caisson excavation device according to claim 2, wherein the blades of the excavation supporter are positioned relatively lower than the horizontal excavator and a difference in height is provided between the two excavators. 5. The caisson outer peripheral surface according to claim 3 or claim 4, wherein the horizontal control device comprises a pair of cylinders that expand and contract with a pair of longitudinal fluid pressures, and tracking means that follows the displacement of each rod of each cylinder. The caisson is configured so that the amount of caisson settlement can be measured through the tracking means while the rods of the pair of cylinders are alternately brought into contact with a plurality of protrusions provided at regular intervals. Drilling rig.

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