JP2019196623A - Drilling machine and drilling method - Google Patents

Abstract

To provide a drilling machine which drills a water bottom ground with a simple structure.SOLUTION: A drilling machine 10 which drills a ground (a water bottom ground) 2 comprises a body part 11 which locates upper than a water surface WS and has a rotation driving source (a motor), and a rotary drilling device 12 which extends downwardly from the body part 11. The rotary drilling device 12 has a rod part 13 which consists of a plurality of cylindrical rod members 13a connected in the vertical direction, and a ground drilling part 14 connected to a lower end of the rod part 13. The rod part 13 and the ground drilling part 14 rotate by rotation driving force from the rotation driving source (the motor) of the body part 11 with the vertical direction as the rotational axis. The ground drilling part 14 rotates and drills the ground 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an excavator for excavating a submarine ground and a method for excavating a submarine ground using the excavator.

  Patent Document 1 discloses an underwater excavator that can be used in a so-called open caisson method. This underwater excavator has a float disposed in the caisson housing and an excavator provided in the lower part of the float. The float is provided with a gripper. By pressing the inner surface of the caisson housing with the gripper, the float can be fixed at an arbitrary position in the caisson housing.

JP-A-6-81349

  However, in the technique disclosed in Patent Document 1, when the reaction force of ground excavation by an excavator is to be taken from the caisson housing, the size of the reaction force receiving device including a float having a gripper is increased. For this reason, it takes time and labor to assemble the reaction force receiving device and to install the reaction force receiving device in the caisson housing, and to increase the cost of these operations.

  In view of such a situation, an object of the present invention is to excavate underwater ground with a simple configuration.

  Therefore, the excavator according to the present invention is an excavator that excavates the water bottom ground. The excavator according to the present invention includes a main body portion that is located above the water surface and has a rotational drive source, and a rotary excavator that extends downward from the main body portion. The rotary excavator includes a rod portion made of a plurality of cylindrical rod members connected in the vertical direction, and a ground excavation portion connected to the lower end of the rod portion. The rod part and the ground excavation part rotate around the vertical direction by the rotational driving force from the rotational drive source, and the ground excavation part rotationally excavates the water bottom ground.

  In the excavation method according to the present invention, the water bottom ground below the caisson enclosure is removed using the above-described excavator in a state where water is introduced into a cylindrical caisson enclosure that extends vertically and is submerged in the ground. It is a method of excavation. The excavation method according to the present invention is assembled with the first step of assembling the rotary excavator by repeatedly adding and lowering the rod member above the water surface until the ground excavation part reaches the bottom of the ground. A second step of connecting the main body portion to the rotary excavator, and a third step of excavating the submarine ground using an excavator.

  According to this invention, the main-body part which has a rotational drive source is located above a water surface. Therefore, for example, when the main body is suspended by a lifting device located on the ground and can be moved up and down, a reaction force for rotation of the rotary excavator can be obtained from the lifting device on the ground. There is no need to provide a large reaction force receiving device such as a float having the above-described gripper, and therefore, the bottom ground can be excavated with a simple configuration.

It is a figure which shows the schematic structure of the sinking method of the caisson housing | casing in 1st Embodiment of this invention, and an excavator. It is a figure which shows the sinking method of the caisson housing in embodiment same as the above. It is a figure which shows the sinking method of the caisson housing in embodiment same as the above. It is a figure which shows the sinking method of the caisson housing in embodiment same as the above. It is a figure which shows the sinking method of the caisson housing in embodiment same as the above. It is a figure which shows the sinking method of the caisson housing in embodiment same as the above. It is a figure which shows the sinking method of the caisson housing in embodiment same as the above. It is a top view which shows the 1st example and 2nd example of the formation pattern of the drilling hole by the excavator in embodiment same as the above. It is a perspective view of the scaffold for rod member addition work in an embodiment same as the above. It is a perspective view of the rod member support apparatus in an embodiment same as the above. It is a figure which shows the addition method of the rod member in embodiment same as the above. It is a figure which shows schematic structure of the trolley | bogie for rod member addition work in embodiment same as the above. It is a top view which shows the formation pattern of the drilling hole by the excavator in 2nd Embodiment of this invention. It is a perspective view of the rod member support device in a 3rd embodiment of the present invention.

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

  1-7 is a figure which shows the sinking method of the caisson housing 1 in 1st Embodiment of this invention. The caisson housing 1 sinking method includes a method of excavating the ground (water bottom ground) 2 below the caisson housing 1. Here, FIGS. 1 to 7 correspond to longitudinal sectional views of the caisson housing 1.

  In the present embodiment, an example in which the excavation method according to the present invention is applied to the construction of a shaft will be described, but the application example of the excavation method according to the present invention is not limited thereto.

  The vertical shaft is constituted by a cylindrical caisson housing 1 that is open at both upper and lower ends and extends in the vertical direction. The caisson housing 1 is made of concrete, for example. In the construction of the shaft in this embodiment, a construction method (so-called open caisson construction method) in which the ground 2 is excavated underwater and the caisson housing 1 is gradually submerged is used. Here, excavation (underwater excavation) of the ground 2 is performed in a state where the water W is introduced into the shaft (caisson housing 1) and the water W is stored in the shaft (caisson housing 1). In the present embodiment, the caisson housing 1 is pressed and submerged into the ground by pressing the caisson housing 1 downward by a ground press-fitting device (not shown). As this press-fitting device, for example, the press-fitting device disclosed in JP-A-10-176477 can be used, but the configuration of the press-fitting device is not limited to this.

  In the present embodiment, the ground (water bottom ground) 2 shown in FIGS. 1 to 7 is a hard ground, and the ground above the ground 2 is a soft ground. In other words, in the present embodiment, from the soft ground side until the ground 2 that is the hard ground is exposed (that is, until the state shown in FIG. 1 is reached), the underwater of the soft ground is within the caisson housing 1. Drilling is performed. This process is referred to as “soft ground excavation process”. In the above-described underwater excavation of soft ground, an excavator 30 (see FIGS. 6 and 7) having a grab bucket 31 (see FIGS. 6 and 7) such as a clamshell bucket that can be freely opened and closed can be used.

  In the method of sinking the caisson housing 1 in the present embodiment, first, as shown in FIGS. 1 and 2, the excavator 10 is placed on the ground 2 in the region adjacent to the inner peripheral surface 1 a of the caisson housing 1 in plan view. Used to drill (perforate) vertically. Thereby, the area | region located in the vicinity of the blade edge part 1b of the caisson housing 1 among the ground 2 is loosened (relaxed). Here, FIG. 2 shows a region (relaxation region) 2a of the ground 2 that has been loosened by a single drilling by the excavator 10.

  In the present embodiment, the excavator 10 forms a plurality of relaxation regions 2a as shown in FIG. These relaxation regions 2a are arranged along the circumferential direction of the caisson housing 1 in plan view. FIGS. 8A and 8B respectively show a first example and a second example of the formation pattern of the drilling holes 3 by the excavator 10 for forming these relaxation regions 2a.

  In the first example shown in FIG. 8A, twelve drilling holes 3 are formed by the excavator 10. Here, the number of the drilling holes 3 is not limited to 12 and is arbitrary. In the first example shown in FIG. 8A, each of the plurality of drilling holes 3 is adjacent to the inner peripheral surface 1 a of the caisson housing 1 in plan view. In the first example shown in FIG. 8A, the plurality of drilling holes 3 are arranged along the circumferential direction of the caisson housing 1 in plan view. That is, in the first example shown in FIG. 8A, excavation is performed using the excavator 10 at a plurality of locations in the ground 2 that are arranged along the circumferential direction of the caisson housing 1 in plan view. In the first example shown in FIG. 8A, a plurality of drilling holes 3 are formed in the ground 2 at intervals in the circumferential direction of the caisson housing 1. In the first example shown in FIG. 8A, the range (volume) of the relaxation region 2a may be greater than or equal to the range (volume) of the drilling hole 3.

  In the second example shown in FIG. 8B, each of the plurality of drilling holes 3 is adjacent to the inner peripheral surface 1 a of the caisson housing 1 in plan view. In the second example shown in FIG. 8B, the plurality of drilling holes 3 are formed in the ground 2 so as to slightly overlap each other in the circumferential direction of the caisson housing 1. In the second example shown in FIG. 8B as well, excavation is performed using the excavator 10 at a plurality of locations in the ground 2 that are arranged along the circumferential direction of the caisson housing 1 in plan view. In the second example shown in FIG. 8B, the range (volume) of the relaxation region 2a may be equal to or greater than the range (volume) of the drilling hole 3.

In the first example shown in FIG. 8 (A), when the caisson housing 1 is difficult to be pressed and settled (see FIGS. 4 and 5) because the strength of the ground 2 is high, the second example shown in FIG. 8 (B). It is preferable to adopt.
Here, the process of forming the relaxation region 2a shown in FIGS. 1 to 3 and 8 is referred to as a “relaxation region formation step”.

  Next, as shown in FIG. 4, the caisson housing 1 is press-fitted and submerged. The above-described ground press-fitting device (not shown) can be used for the press-fitting and sinking of the caisson housing 1. Thereafter, the caisson housing 1 is press-fitted and subsidized to a predetermined depth by repeatedly constructing a new cylindrical lot so as to be connected to the upper end of the caisson housing 1 and press-fitting and sinking the caisson housing 1 ( (See FIG. 5). Here, the caisson housing 1 may be configured to include a plurality of lots constructed at the construction site, or includes a lot manufactured at a factory or the like away from the construction site (a lot made of a so-called precast material). It may be constituted by.

Next, as shown in FIG.6 and FIG.7, using the excavation apparatus 30 which has the grab bucket 31, the area | region located in the caisson housing 1 in planar view among the ground 2 is excavated. This process is referred to as a “bucket excavation process”. The excavator 30 includes, for example, a mobile crane 32 disposed on the ground and a grab bucket 31 suspended from the tip of a boom 33 of the mobile crane 32. The grab bucket 31 includes a pair of shells 31a that can be opened and closed.
In this way, the caisson housing 1 is laid.

  Returning to FIG. 1, a schematic configuration of the excavator 10 will be described. The excavator 10 is an excavator that excavates the ground 2 in the vertical direction. The excavator 10 includes a main body portion 11 located above the water surface WS in the caisson housing 1, a rotary excavator 12 extending downward from the main body portion 11, and a lifting device 20 located on the ground.

  The main body 11 includes a motor (for example, a hydraulic motor or an electric motor) that functions as a rotational drive source and a speed reducer (both not shown).

  The rotary excavator 12 includes a rod part 13 and a ground excavation part 14 connected to the lower end of the rod part 13. The rod portion 13 includes a plurality of cylindrical rod members 13a (see FIGS. 9 to 11) connected in the vertical direction. Each rod member 13a and the rod part 13 are extended in the up-down direction.

  In the present embodiment, the ground excavation part 14 includes an auger part 15. The auger portion 15 has a shaft portion 15a extending in the vertical direction and a spiral blade 15b provided on the outer periphery of the shaft portion 15a. In addition, the auger portion 15 may have a cutting head (not shown) at the lower end of the shaft portion 15a.

  The upper end of the rod part 13 is connected to the output shaft of the motor of the main body part 11 via the speed reducer of the main body part 11. The lower end of the rod portion 13 is connected to the upper end of the shaft portion 15 a of the auger portion 15. Therefore, the rotary excavator 12 having the rod portion 13 and the ground excavating portion 14 extends downward from the main body portion 11. Further, the rotary excavator 12 having the rod portion 13 and the ground excavating portion 14 rotates about the vertical direction as a rotation axis by the rotational driving force from the motor of the main body portion 11 and also excavates the ground 2.

  In the present embodiment, the lifting device 20 includes a base machine 21 and a boom arm 22 that is pivotally supported by the base machine 21 via a pivot shaft (not shown) and can swing in the vertical direction.

  The base machine 21 is, for example, a general-purpose hydraulic excavator base machine. The base machine 21 includes a crawler belt 23 which is a traveling means installed in the lower part thereof, a base machine main body 24, and a turning device (not shown) for horizontally turning the base machine main body 24 with respect to the crawler belt 23 above. Is provided. That is, the base machine 21 is an all-round base machine equipped with a crawler belt 23 in the lower part. In the present embodiment, the crawler belt 23 is used as the traveling means of the base machine 21, but the traveling means is not limited to the crawler belt 23, and for example, wheels may be used as the traveling means.

  The boom arm 22 can swing in the vertical direction with respect to the base machine body 24 and can bend and stretch by extending or contracting at least one of the jacks 27 to 29.

  The main body 11 is suspended from the tip of the boom arm 22. Here, the main body 11 is attached to the tip of the boom arm 22 so that a reaction force for the rotation of the rotary excavator 12 can be sufficiently obtained from the lifting device 20. The main body 11 can be raised and lowered by swinging the boom arm 22 in the vertical direction. Further, the excavator 10 can perform rotary excavation while pressing the ground (water bottom ground) 2 downward by the weight of the main body 11 and the rotary excavator 12.

  The rod portion 13 is provided with at least one inclinometer (not shown). When only one inclinometer is provided in the rod portion 13, the inclinometer is provided in the lower half region of the rod portion 13. When there are a plurality of inclinometers provided in the rod portion 13, at least one of the plurality of inclinometers is provided in the lower half region of the rod portion 13. FIG. 1 shows an example in which two inclinometers (not shown) are provided on the rod portion 13, and one inclinometer is provided at each of the positions P1 and P2 shown in FIG. Here, the inclinometer provided at the position P2 located on the lower side among the positions P1 and P2 is located in the lower half region of the rod portion 13.

  The above-mentioned inclinometer is accommodated in the rod part 13, for example. Such an inclinometer is disclosed in Japanese Patent No. 2951945 and Japanese Patent No. 3234774, and since it is a well-known technique, its description is omitted. The data measured by the inclinometer (for example, measurement data such as the degree of inclination of the rod portion 13 in the vertical direction at the installation position of the inclinometer) is, for example, a transmitter (not shown) housed in the rod portion 13. To the ground receiver (not shown), and based on this, the measurement result can be displayed on the ground display. By monitoring this measurement result when the excavator 10 is operated, the worker can easily grasp the inclination state of the rod portion 13 and the bending state of the rod portion 13.

  Next, a method of connecting the rod members 13a (method of adding the rod members 13a) will be described with reference to FIGS. FIG. 9 is a perspective view of the scaffold 40 for rod member addition work in the present embodiment. FIG. 10 is a perspective view of the rod member support device 46 in the present embodiment. FIG. 11 is a diagram illustrating a method of adding the rod member 13a in the present embodiment. In the following description, the front, rear, left and right (see FIGS. 9 and 10) are defined with reference to the orientation of the worker M during the rod member addition work shown in FIG.

  In this embodiment, the scaffold 40 is used for the addition work of the rod member 13a. The scaffold 40 includes a scaffold main body 41 for the worker M to perform the work and a support portion 42 that cantilever-supports the scaffold main body 41. The support portion 42 includes a base portion 43 that is formed on the ground outward in the radial direction of the caisson housing 1 and is fixed to the ground, and a pair of column portions 44 that are erected from the base portion 43. The scaffold body 41 has a rectangular shape in plan view, and in the long side direction, one end portion 41a is fixed to the upper part of the pair of pillar portions 44, and the intermediate portion 41b passes horizontally above the caisson housing 1 horizontally. The other end portion 41 c is located immediately above the water surface WS radially inward of the caisson housing 1. That is, the scaffold body 41 extends from the radially outer side to the inner side of the caisson housing 1, and one end portion 41 a thereof is cantilevered by the support portion 42. The scaffold body 41 is installed above the water surface WS.

  A rod member support device 46 is detachably attached to the other end portion 41 c of the scaffold body 41. The rod member support device 46 includes a pair of left and right beam members 47 extending in the front-rear direction, and a rotation suppression unit 48 provided on each beam member 47 and suppressing the rotation of the rod member 13a. The rear end portion of the beam member 47 is detachably attached to the other end portion 41c of the scaffold main body 41 via a clamp (not shown) (eg, Bullman (registered trademark)). There is a gap between the pair of left and right beam members 47, and the rod member 13a can enter the gap. This gap is slightly larger than the outer diameter of the rod member 13a.

  The beam member 47 is formed of H-shaped steel. The rotation suppressing portion 48 is composed of a pair of front and rear square steel members 48 a extending in the left-right direction, and is fixed to the upper flange of the beam member 47. A pair of plate members 13b are fixed in advance on the outer peripheral surface of the upper end portion of each rod member 13a so as to project outward in the radial direction, and the plate members 13b are positioned between the pair of square steel members 48a. In this state, the beam member 47 can be placed on the upper flange. In this placement state, the rotation of the rod member 13a is suppressed by the rotation suppression unit 48 via the pair of plate members 13b.

  In the extension work of the rod member 13a, first, as shown in FIG. 11A, the rod member 13a added last time on the rod member support device 46 detachably attached to the other end portion 41c of the scaffold body 41 is used. Hook a pair of plate members 13b. Thereby, the rod member 13a added last time is supported by the rod member support device 46 via the pair of plate members 13b. At this time, the plate member 13b is placed on the upper flange of the beam member 47 in a state of being positioned between the pair of square steel members 48a.

  Next, as shown in FIG. 11B, the lower end portion of the new rod member 13a added this time is connected to the upper end portion of the rod member 13a added last time. The connected rod members 13a and 13a are suspended and supported by a lifting device such as a crane (not shown).

Next, as shown in FIG. 11 (C), the above-mentioned clamping fittings are loosened, and the rod member support device 46 is moved with respect to the other end portion 41c of the scaffold body 41, so that it is placed on the beam member 47. The plate member 13 b that has been removed is separated from the rod member support device 46. Thereafter, the above-mentioned connected rod members 13a and 13a are lowered while being supported by being suspended.
By repeating the above, the rod members 13a are sequentially added.

The above-described method of sinking the caisson housing 1 (a method of excavating the ground (submarine ground) 2 below the caisson housing 1) may include the following first to third steps.
[First step]
The process of assembling the rotary excavator 12 by repeating the addition of the rod member 13a above the water surface WS and the lowering of the added rod member 13a until the ground excavation unit 14 reaches the water bottom ground (rotary excavator 12) Forming step).
[Second step]
A step of connecting the main body 11 to the assembled rotary excavator 12 (main body connecting step).
[Third step]
A step of excavating the ground (submarine ground) 2 using the excavator 10 (the aforementioned relaxation region forming step).

  Here, the second step described above may include attaching the main body 11 to the tip of the boom arm 22 of the lifting device 20 (main body hanging process).

  According to the present embodiment, the excavator 10 is an excavator that excavates the ground (water bottom ground) 2. The excavator 10 includes a main body 11 that is located above the water surface WS and has a rotational drive source (motor), a rotary excavator 12 that extends downward from the main body 11, and a lifting device 20 that is located on the ground. . The main body 11 can be lifted and lowered by being suspended by the lifting device 20. The rotary excavator 12 includes a rod portion 13 composed of a plurality of cylindrical rod members 13 a connected in the vertical direction, and a ground excavation portion 14 connected to the lower end of the rod portion 13. The rod part 13 and the ground excavation part 14 rotate about the vertical direction by the rotational driving force from the rotational drive source (motor) of the main body part 11, and the ground excavation part 14 rotates and excavates the ground (submarine ground) 2. . Thereby, since the reaction force for rotation of the rotary excavator 12 can be obtained from the lifting device 20 on the ground, the ground (submarine ground) 2 can be obtained with a simple configuration without taking the reaction force from the caisson housing 1. Can be excavated.

  Further, according to the present embodiment, the lifting device 20 includes a fully-rotating base machine (base machine 21) equipped with traveling means (for example, a crawler belt 23) in the lower part, and a base end portion pivotally supported by the base machine 21. And a boom arm 22 that can swing in the vertical direction. The main body 11 is suspended from the tip of the boom arm 22. Thereby, a general-purpose hydraulic excavator base machine can be used as the lifting device 20 constituting the excavator 10.

  According to the present embodiment, the excavator 10 further includes at least one inclinometer provided in the rod portion 13. The inclinometer is provided in the lower half region of the rod portion 13. Thereby, it is possible to monitor the lower half region of the rod portion 13, which tends to be inclined or bent more than the upper half region of the rod portion 13.

  Moreover, according to this embodiment, the ground excavation part 14 contains the auger part 15 which has the spiral blade 15b. Thereby, the earth auger used with what is called Anguilas pile driver and RX pile driver can be used as the auger part 15.

  In addition, according to the present embodiment, the ground below the caisson housing 1 using the excavator 10 in a state where the water W is introduced into the cylindrical caisson housing 1 extending in the vertical direction and set in the ground. The method of excavating the (water bottom ground) 2 includes adding the rod member 13a above the water surface WS and lowering the added rod member 13a until the ground excavating section 14 reaches the ground (water bottom ground) 2. By repeating (see FIGS. 9 to 11), a first step of assembling the rotary excavator 12, a second step of connecting the main body 11 to the assembled rotary excavator 12 (see FIG. 1), and excavation And a third step (see FIGS. 1 to 3 and FIG. 8) for excavating the ground (water bottom ground) 2 using the machine 10. Thereby, for example, even if the rod portion 13 has a length of several tens of meters, the rod portion 13 can be formed by simply connecting (adding) a plurality of rod members 13a.

  Further, according to the present embodiment, in the above-described third step, the excavator 10 is used to excavate the area adjacent to the inner peripheral surface 1a of the caisson housing 1 in plan view in the ground (water bottom ground) 2. (See FIGS. 1 to 3 and FIG. 8). Thereby, the area | region located in the vicinity of the blade edge part 1b of the caisson housing 1 can be loosened among the grounds (water bottom ground) 2 (that is, the ground can be loosened).

  Further, according to the present embodiment, in the above-described third step, excavation is performed using the excavator 10 at a plurality of locations arranged along the circumferential direction of the caisson housing 1 in plan view in the ground (water bottom ground) 2. (See FIGS. 1 to 3 and FIG. 8). Thereby, the area | region located in the vicinity of the blade edge part 1b of the caisson housing 1 among the grounds (water bottom ground) 2 can be loosened over a wide range (for example, over the entire circumference).

  According to the present embodiment, in the method of excavating the ground (water bottom ground) 2 below the caisson housing 1 using the excavator 10 in a state where the water W is introduced into the caisson housing 1, Prior to the first step, the submarine ground (soft ground) is excavated using the excavator 30 having the openable and closable grab bucket 31 (refer to the aforementioned “soft ground excavation step”). Thereby, when caisson housing 1 is press-fitted and subsidized in soft ground, the ground can be efficiently excavated by excavator 30 having grab bucket 31.

  Moreover, according to this embodiment, the caisson housing 1 is press-fitted and sunk after the above-mentioned third step (see FIGS. 4 and 5). As a result, the caisson housing 1 can be pressed and settled after the strength of the region located in the vicinity of the edge 1b of the caisson housing 1 in the ground (submarine ground) 2 can be lowered. ) Even if 2 is hard ground, the caisson housing 1 can be press-fitted and subsidized efficiently.

  Moreover, according to this embodiment, the rod member 13a addition work in the first step is performed on the scaffold 40 (scaffold body 41) installed above the water surface WS (see FIGS. 9 to 11). Thereby, the addition work of the rod member 13a can be performed with a simple configuration. In this embodiment, the rod member 13a is added on the scaffold 40 (the scaffold body 41). Instead, the rod member 13a is added on the watercraft 50 that floats on the water surface WS. You may carry out above (refer FIG. 12). Here, FIG. 12 is a diagram showing a schematic configuration of the trolley 50 for rod member addition work. Also in this case, the rod member support device 46 described above can be used. That is, the rod member support device 46 can be detachably attached to the carriage 50.

FIG. 13 is a plan view showing a formation pattern of the drilling holes 3 by the excavator 10 in the second embodiment of the present invention.
Differences from the first embodiment will be described.

  In the above-described relaxation region forming step, that is, the step of excavating the ground (water bottom ground) 2 using the excavator 10, a plurality of drill holes 4 are formed in the central portion of the caisson housing 1 in plan view. Moreover, in this embodiment, the some drilling hole 4 is formed in the ground (water bottom ground) 2 so that it may be enclosed by the some drilling hole 3 by planar view. In the present embodiment, four holes 4 are formed in the ground 2, but the number of holes 4 is not limited to this and is arbitrary.

  Here, FIG. 13 shows a case where a plurality of holes 4 are added in the first example of the formation pattern of the holes 3 by the excavator 10 shown in FIG. It goes without saying that a plurality of holes 4 can be added also in the second example of the formation pattern of the holes 3 by the excavator 10 shown in FIG.

  In particular, according to the present embodiment, since the plurality of drill holes 4 can be formed in the ground (water bottom ground) 2 using the excavator 10 in the above-described relaxation region forming step, the ground (water bottom ground) 2 is spread over a wide range. It can be loosened, and as a result, the earth and sand of the ground can be easily grasped by the grab bucket 31. Therefore, the workability of excavation in the above-described bucket excavation process can be improved. Here, it is preferable that the interval between the adjacent holes 4 is narrower than the maximum opening width of the grab bucket 31 (the opening width of the grab bucket 31 in the opened state of the grab bucket 31 shown in FIGS. 6 and 7).

FIG. 14 is a perspective view of a rod member support device 46 according to the third embodiment of the present invention.
Differences from the first embodiment will be described.

  In the first embodiment described above, the rotation suppressing portion 48 provided on each beam member 47 is composed of a pair of front and rear square steel members 48a. In the present embodiment, the front side of the pair of front and rear square steel members 48a. The square steel material 48a is replaced with a plate-shaped steel material 48b.

  The plate-like steel material 48b is substantially the same height as the plate member 13b. The adjacent plate-like steel material 48b and the plate member 13b can be detachably fixed to each other by a clamp (not shown) (for example, Bullman (registered trademark)). Thereby, rotation of the rod member 13a at the time of rod member addition work can be suppressed significantly.

  In the first to third embodiments described above, the bucket excavation step is performed after the caisson housing 1 is press-fitted and submerged. Good.

  In the above-described first to third embodiments, the lifting device 20 of the excavator 10 includes the base machine 21 and the boom arm 22, but the configuration of the lifting device 20 is not limited thereto. For example, the lifting device 20 may be a mobile crane (eg, a rough terrain crane). When the lifting device 20 is a rough terrain crane, the main body 11 can be suspended at the tip of the boom. Even in this case, the main body 11 can be attached to the tip of the boom so that a reaction force for rotating the rotary excavator 12 can be sufficiently obtained from the lifting device 20.

  In the first to third embodiments described above, the ground excavation unit 14 constituting the rotary excavation device 12 is configured to include the auger unit 15, but the configuration of the ground excavation unit 14 is not limited to this, for example, the lower end A rod including a cutting head may be included.

  In the first to third embodiments described above, the cross-sectional shape of the caisson housing 1 is circular. However, the cross-sectional shape of the caisson housing 1 is not limited to a circle, and may be, for example, an ellipse or a rectangle.

  In the first to third embodiments described above, the example in which the excavation method according to the present invention is applied to the construction of a shaft has been described, but the application example of the excavation method according to the present invention is not limited thereto. For example, the excavation method according to the present invention may be applied to the construction of underground structures other than shafts and the construction of foundations of structures.

  The illustrated embodiments are merely examples of the present invention, and the present invention includes various improvements and modifications made by those skilled in the art within the scope of the claims in addition to those directly illustrated by the described embodiments. Needless to say, it is included.

  DESCRIPTION OF SYMBOLS 1 ... Caisson housing, 1a ... Inner peripheral surface, 1b ... Blade edge part, 2 ... Ground (water bottom ground), 2a ... Relaxation area, 3, 4 ... Drilling hole, 10 ... Excavator, 11 ... Main part, 12 ... Rotation Excavator 13 ... Rod part, 13a ... Rod member, 13b ... Plate member, 14 ... Ground excavation part, 15 ... Auger part, 15a ... Shaft part, 15b ... Spiral blade, 20 ... Lifting device, 21 ... Base machine, DESCRIPTION OF SYMBOLS 22 ... Boom arm, 23 ... Track, 24 ... Base machine main body, 27-29 ... Jack, 30 ... Excavator, 31 ... Grab bucket, 31a ... Shell, 32 ... Mobile crane, 33 ... Boom, 40 ... Scaffold, 41 ... Scaffolding body, 41a ... One end, 41b ... Intermediate part, 41c ... Other end, 42 ... Supporting part, 43 ... Base part, 44 ... Column part, 46 ... Rod member supporting device, 47 ... Beam member, 48 ... Rotation Suppression part, 48a ... Square steel, 48 ... plate-shaped steel, 50 ... barge, M ... worker, P1, P2 ... position, W ... water, WS ... water surface

Claims (12)

An excavator for excavating underwater ground,
A main body having a rotational drive source located above the water surface;
A rotary excavator extending downward from the main body;
With
The rotary excavator has a rod part composed of a plurality of cylindrical rod members connected in the vertical direction, and a ground excavation part connected to the lower end of the rod part,
The rod part and the ground excavation part rotate about the vertical direction as a rotation axis by the rotational driving force from the rotational driving source,
The ground excavation unit is an excavator that rotates and excavates the bottom of the ground. Further comprising a lifting device located on the ground,
The excavator according to claim 1, wherein the main body portion is lifted and lowered by the lifting device. The lifting device is
An all-swivel base machine equipped with traveling means at the bottom,
A boom arm pivotally supported in the base machine and pivotable in the vertical direction;
Have
The excavator according to claim 2, wherein the main body is suspended from a tip of the boom arm.   The excavator according to claim 2, wherein the lifting device is a rough terrain crane. Further comprising at least one inclinometer provided in the rod portion;
The excavator according to any one of claims 1 to 4, wherein the inclinometer is provided in a lower half region of the rod portion.   The excavator according to any one of claims 1 to 5, wherein the ground excavation part includes an auger part having a spiral blade. The caisson housing using the excavator according to any one of claims 1 to 6, in a state where water is introduced into a cylindrical caisson housing that extends in the vertical direction and is submerged in the ground. A method of excavating a lower bottom ground,
A first step of assembling the rotary excavator by repeating the addition of the rod member above the water surface and the lowering of the added rod member until the ground excavation part reaches the bottom of the ground;
A second step of connecting the main body to the assembled rotary excavator;
A third step of excavating submarine ground using the excavator;
Including a drilling method.   8. The excavation method according to claim 7, wherein in the third step, an area adjacent to an inner peripheral surface of the caisson housing in a plan view is excavated using the excavator in the water bottom ground.   The excavation according to claim 7 or 8, wherein, in the third step, excavation is performed by using the excavator at a plurality of locations arranged along the circumferential direction of the caisson housing in a plan view in the bottom of the ground. Method.   The excavation method according to any one of claims 7 to 9, wherein, prior to the first step, the submarine ground is excavated using an excavator having a grab bucket that can be freely opened and closed.   The excavation method according to any one of claims 7 to 10, wherein the caisson housing is press-fitted and settled after the third step.   The addition work of the rod member in the first step is performed on a scaffold installed above the water surface, or is performed on a base boat that floats on the water surface. Drilling method as described in.