Ground excavation methods and ground excavation systems

Abstract

To provide a ground excavation method or system that allows for efficient and flexible ground excavation even when hard rock mass is unevenly distributed at the tip of the casing, by displacing the excavator within the casing. [Solution] The ground excavation method includes a casing press-in step in which a cylindrical casing is pressed into place while being rotated by a full-circumference rotating device, and a casing tip excavation step in which, if hard rock mass is present at the tip of the casing during the casing press-in step, the hard rock mass at the tip of the casing is excavated, and the casing tip excavation step includes a table machine installation step in which a table machine to which a hard excavator for excavating the hard rock mass can be operably mounted is installed on the full-circumference rotating device, a hard excavator displacement step in which the hard excavator attached to the table machine is displaced from the center of the casing, and a hard rock excavation step in which the hard rock mass is excavated with the hard excavator.

Description

Technical Field

[0003]

[0001] The present invention belongs to the technical field related to ground excavation, and particularly relates to a casing excavation method and system using a full-rotation device and a table machine.

Background Art

[0002] Conventionally, as a method for excavating the ground, the all-casing method is known. In this all-casing method, a steel pipe called a cylindrical casing is pushed vertically into the ground while being rotated by a full-rotation device to dig down the ground.

[0003] At this time, it may include a process of using a hammer grab provided on a crane to excavate the ground inside the casing while discharging the soil. This hammer grab is suitable for relatively soft ground or shallow excavation, but when reaching a hard rock layer, the excavation speed significantly decreases, which may lead to a deterioration in work efficiency.

[0004] In addition, in the process of excavation while pushing in the casing, the frictional resistance due to the tightening of the rock layer increases. As a result, it becomes difficult to press-fit the casing, not only increasing the load on the machinery required for the work, but also lengthening the excavation period and increasing the cost.

[0005] In the ground excavation method described in Patent Document 1, when the casing is press-fitted by a full-rotation device and excavation is performed using a hammer grab and reaching a hard rock layer, it is proposed to excavate the hard rock layer with a down-the-hole hammer.

[0006] That is, in this technique, a table machine is attached above the full-rotation device, a down-the-hole hammer connected to the table machine is inserted into the casing, and the table machine rotates this to disclose a method for efficiently excavating the rock layer.

Prior Art Documents

Patent Documents

[0007] [Patent Document 1] Patent No. 7016567 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, depending on the ground being excavated, the hard rock mass may be located to the side rather than in the center of the casing tip. In such cases, there was a problem in that a down-the-hole hammer positioned in the center of the casing may not be able to properly excavate the hard rock mass.

[0009] This invention was proposed to solve the above-mentioned problems, and aims to provide a ground excavation method or system that can displace the excavator within the casing and perform ground excavation efficiently and flexibly even when hard rock mass is unevenly distributed. [Means for solving the problem]

[0010] (1) The ground excavation method according to the present invention includes a casing press-in step in which a cylindrical casing is pressed in while being rotated by a full-circumference rotating device, and a casing tip excavation step in which, if hard rock mass is present at the tip of the casing during the casing press-in step, the hard rock mass at the tip of the casing is excavated, the casing tip excavation step includes a table machine installation step in which a table machine to which a hard excavator for excavating the hard rock mass can be operably attached is installed on the full-circumference rotating device, a hard excavator displacement step in which the hard excavator attached to the table machine is displaced from the center of the casing after the table machine installation step, and a hard rock excavation step in which the hard rock mass is excavated by the hard excavator after the hard excavator displacement step.

[0011] This ground excavation method, by incorporating a hard excavator displacement mechanism, allows for precise displacement of the hard excavator to its location even if hard bedrock is present to the side of the casing tip, enabling efficient and reliable excavation. This expands the excavation range within the casing, allows for flexible adaptation to ground conditions, and significantly improves excavation efficiency.

[0012] (2) In the ground excavation method described above, the excavator displacement step may include a radial movement process that moves the hard excavator radially outward from the casing.

[0013] This ground excavation method includes a radial movement process in which the hard excavator is moved radially, allowing for easy changes in the position of the hard excavator and reducing the time required to remove hard rock.

[0014] (3) In the ground excavation method described above, the excavator displacement step may include a circumferential movement process in which the hard excavator is rotated in an arc shape along the outer circumference of the casing and moved in the circumferential direction.

[0015] This ground excavation method includes a circumferential movement process in which the rigid excavator is moved in an arc along the outer circumference of the casing, enabling excavation along the entire circumference of the casing tip. Combined with the radial movement process of the rigid excavator, this allows excavation with the rigid excavator to be performed at any position along the casing tip.

[0016] (4) In the ground excavation method described above, the circumferential movement process may involve rotating the table machine by rotating the all-around rotating device, thereby moving the hard excavator attached to the table machine in the circumferential direction.

[0017] This ground excavation method employs a configuration in which a table machine is operated by rotating a 360-degree rotating device, thereby moving the hard excavator in the circumferential direction. As a result, the equipment configuration is simplified, and it demonstrates high practicality by reducing equipment costs while maintaining excavation efficiency.

[0018] (5) The casing may include an internal casing drilling step, which involves drilling inside the casing, after the casing press-fitting step and before the casing tip drilling step.

[0019] This ground excavation method allows for the pre-removal of unnecessary soil and rock fragments from the area to be excavated by adding an internal casing excavation step. This improves work efficiency when excavating hard rock, streamlines the excavation process, and increases the overall construction speed.

[0020] (6) The ground excavation system described above comprises a full-circumference rotating device for rotating and pressing in a cylindrical casing, a table machine installed above the full-circumference rotating device, and a hard excavator attached to the table machine that moves inside the casing and excavates the tip of the casing, wherein the table machine is equipped with a hard excavator displacement mechanism that displaces the hard excavator relative to the casing.

[0021] This ground excavation system uses a table machine equipped with a hard excavator to excavate inside the casing, and a displacement mechanism allows it to adjust its position to match the hard rock mass. This configuration allows it to adapt to a variety of ground conditions and achieves high flexibility and construction accuracy, especially in excavation work in hard rock mass.

[0022] (7) In the ground excavation system described above, the hard excavator displacement mechanism may include a radial movement mechanism that moves the hard excavator radially outward from the casing.

[0023] This ground excavation system incorporates a radial movement mechanism that moves the hard excavator radially, effectively expanding the excavation range. As a result, it becomes possible to target specific locations within the casing, eliminating unnecessary excavation and achieving efficient work.

[0024] (8) In the ground excavation system described above, the radial movement mechanism moves the hard excavator radially outward by a predetermined distance.

[0025] According to this ground excavation system, by moving the hard rock excavator radially by a predetermined dimension, the accuracy of excavation is improved. With this configuration, flexible setting according to construction conditions becomes possible, and it becomes possible to reduce materials and working hours by preventing over-excavation.

[0026] (9) The full rotation device includes an installation mechanism to which the table machine is rotatably attached.

[0027] According to this ground excavation system, by having a configuration in which the full rotation device can rotatably install the table machine, while ensuring the stability of the device during the excavation work, easy installation and removal become possible. As a result, the work efficiency is improved and the operation cost of the device is reduced.

[0028] (10) The hard rock excavator may be rotated by the table machine to excavate the hard rock formation at the tip of the casing.

[0029] According to this ground excavation system, a configuration is adopted in which the hard rock excavator is rotated by the table machine for excavation. Thereby, the efficiency of hard rock formation excavation is improved, and the excavation accuracy of the tip portion of the casing is further enhanced. Also, the operation becomes easier due to the simplification of the device.

[0030] (11) Another ground excavation method according to the present invention includes a casing pressing step of pressing a cylindrical casing while rotating it by a full rotation device, and when there is a hard rock formation at the tip of the casing during the casing pressing step, a casing tip excavation step of excavating the hard rock formation at the tip of the casing. The casing tip excavation step includes a hard rock excavator installation process of attaching the hard rock excavator to the full rotation device, a hard rock excavator displacement process of displacing the hard rock excavator attached to the full rotation device from the center of the casing after the hard rock excavator installation process, and a hard rock formation excavation process of excavating the hard rock formation by the hard rock excavator after the hard rock excavator displacement process.

[0031] This ground excavation method, by incorporating a hard excavator displacement mechanism, allows for precise displacement of the hard excavator to its location even if hard bedrock is present to the side of the casing tip, enabling efficient and reliable excavation. This expands the excavation range within the casing, allows for flexible adaptation to ground conditions, and significantly improves excavation efficiency.

[0032] (12) Another ground excavation system according to the present invention comprises a full-circumference rotating device for rotating and pressing in a cylindrical casing, and a hard excavator attached to the full-circumference rotating device, wherein the hard excavator is attached to the full-circumference rotating device so as to be movable in the radial direction of the casing, and moves in the circumferential direction as the full-circumference rotating device rotates.

[0033] This ground excavation system uses a table machine equipped with a hard excavator to excavate inside the casing, and a displacement mechanism allows it to adjust its position to match the hard rock mass. This configuration allows it to adapt to a variety of ground conditions and achieves high flexibility and construction accuracy, especially in excavation work in hard rock mass. [Effects of the Invention]

[0034] According to the present invention, in the all-casing method, regardless of the location of the hard rock mass at the tip of the casing, it is possible to accurately displace the hard rock drilling machine to that location and perform drilling efficiently and reliably. [Brief explanation of the drawing]

[0035] [Figure 1] This is a flowchart showing the steps of a ground excavation method according to an embodiment of the present invention. [Figure 2] Figure 1 is a flowchart showing the process of the casing press-fitting step. [Figure 3] Figure 1 is a flowchart showing the process of the casing drilling step. [Figure 4] Figure 1 is a flowchart showing the process of the casing tip drilling step. [Figure 5]Figure 4 is a plan view showing the deformation flow of the ground excavation system during the displacement process of the hard excavator. [Figure 6] This is a front view of a ground excavation system according to an embodiment of the present invention. [Figure 7] This is a side view of a ground excavation system according to an embodiment of the present invention. [Figure 8] This is a plan view of a ground excavation system according to an embodiment of the present invention. [Figure 9] This is a flowchart showing the process of the tip excavation step of a ground excavation method according to a modified example of the present invention. [Figure 10] Figure 9 is a plan view showing the deformation flow of the ground excavation system during the displacement process of the hard excavator. [Modes for carrying out the invention]

[0036] A ground excavation method S and a ground excavation system D according to an embodiment of the present invention will be described with reference to the drawings.

[0037] <Ground excavation methods> As shown in Figure 1, the ground excavation method S according to this embodiment includes a casing press-in step S1, a casing internal excavation step S2, a casing tip excavation step S3, a casing re-press-in step S4, a casing internal re-excavation step S5, and a finishing step S6. If the tip of the casing 2 reaches hard rock G after the casing internal re-excavation step S5, the process may return to the casing tip excavation step S3.

[0038] As shown in Figure 2, the casing press-fitting step S1 includes a full-circumference rotating device installation step S11 (see Figure 2(A)) in which the full-circumference rotating device 1 is installed on the ground, a casing attachment step S12 (see Figure 2(B)) in which the cylindrical casing 2 is attached to the full-circumference rotating device 1, and a casing press-fitting step S13 (see Figure 2(C)) in which the casing 2 attached to the full-circumference rotating device 1 is rotated and press-fitted.

[0039] In the full-circumference rotation device installation process S11, the device is adjusted to a stable horizontal position on the ground surface and positioned in an operational state. In the casing attachment process S12, the cylindrical casing 2 is fixed to the full-circumference rotation device 1 so that the casing 2 can rotate properly and be pressed into place. In the casing press-fitting process S13, the full-circumference rotation device 1 is activated, and the tip of the casing 2 moves forward while scraping the ground, pressing the casing 2 into the ground, so that excavation and press-fitting proceed simultaneously.

[0040] In the casing press-in process S13 of the casing press-in step S1, the tip of the casing 2 advances while scraping the ground, so that excavation and press-in are performed simultaneously. In this embodiment, the casing press-in process S13 is performed until the tip of the casing 2 reaches hard ground.

[0041] As shown in Figure 3, the casing excavation step S2 includes a ground excavator insertion step S21 (see Figure 3(A)) in which a ground excavator 3 suspended by a crane is inserted into the casing 2, a ground excavator operation step S22 (see Figure 3(B)) in which the ground excavator 3 is made to capture soil and sand inside the casing 2, and a ground excavator soil removal step S23 (see Figure 3(C)) in which the soil and sand captured by the ground excavator 3 is carried out of the casing 2, thereby removing soil and rock fragments from inside the casing 2. In this embodiment, the ground excavator 3 is described as a hammer grab.

[0042] In the excavator insertion process S21, the hammer grab 3 is designed to fit the inner diameter of the casing 2 and is capable of capturing soil and debris. In the excavator operation process S22, the hammer grab 3 is operated to capture the soil and crushed ground inside. If necessary, the hammer grab 3 can also activate its claws to break up hard layers. In the excavator soil discharge process S23, the captured soil and debris are discharged to the outside of the casing 2. This series of processes is repeated to advance excavation to the design depth.

[0043] In the casing excavation step S2, the ground is excavated to the required depth by repeating the ground excavator insertion step S21, the ground excavator operation step S22, and the ground excavator soil removal step S23. In addition, the casing excavation step S2 is performed after the tip of the casing 2 has advanced to a predetermined depth by the casing press-in step S1, but if the length of the casing 2 is insufficient to reach the desired depth, a casing 2 addition step may be included in which an additional casing 2 is added.

[0044] As shown in Figure 4, the casing tip drilling step S3 includes a table machine installation step S31 (see Figure 4(A)), a hard drilling machine installation step S32 (see Figure 4(B)) in which a hard drilling machine 5 such as a down-the-hole hammer is attached to the table machine 4, a hard drilling machine displacement step S33 (see Figure 4(C)) in which the hard drilling machine 5 attached to the table machine 4 is displaced from the center of the casing 2, a hard rock drilling step S34 (see Figure 4(D)) in which the hard drilling machine 5 drills into hard rock G at the tip of the casing 2, and a hard drilling machine removal step (not shown) in which the hard drilling machine 5 is removed from the casing 2. The casing tip drilling step S3 is performed when the tip of the casing 2 reaches the hard rock G by the casing press-fitting step S1.

[0045] In the table machine installation process S31, the table machine 4 is installed on top of the all-around rotating device 1. The table machine 4 rotates the hard drilling machine 5. In the hard drilling machine mounting process S32, the hard drilling machine 5, such as a down-the-hole hammer, is attached to the table machine 4 and connected to a drive device (not shown). The roughly cylindrical hard drilling machine 5 has an outer diameter smaller than the inner diameter of the casing 2.

[0046] As shown in Figure 5, the hard drilling machine displacement process S33 includes a radial movement process in which the hard drilling machine 5 (see Figure 5(A)), which is mounted approximately at the center of the table machine 4, is moved radially outward from the center of the casing 2 (see Figure 5(B)), and a circumferential movement process in which the table machine 4 is rotated by the circumferential rotation device 1, causing the hard drilling machine 5 mounted on the table machine 4 to rotate (revolve) in an arc along the outer circumference of the casing 2 and move circumferentially (see Figure 5(C)). Note that the intersection of the dashed-dotted line X and the dashed-dotted line Y in Figure 5 indicates the center of the casing 2.

[0047] In the hard drilling machine displacement process S33, the hard drilling machine 5 is displaced, allowing for concentrated drilling of a portion of the inner circumference of the tip of the casing 2. The radial and circumferential movement distances are adjusted according to the position of the hard rock mass G.

[0048] In the hard rock drilling process S34, the hard drilling machine 5 rotates (rotates on its own axis) on the table machine 4 to drill through the hard rock G and ground at the tip of the casing 2, advancing to the required depth. In the hard drilling machine removal process, after the drilling of the hard rock G is completed, the hard drilling machine 5 and the table machine 4 are removed from the 360-degree rotating device 1.

[0049] The casing re-pressing step S4 includes a casing mounting step (not shown) in which the cylindrical casing 2 is reattached to the circumferential rotating device 1, and a casing re-pressing step (not shown) in which the casing 2 attached to the circumferential rotating device 1 is rotated and pressed in.

[0050] The casing re-excavation step S5 includes a ground excavator re-insertion step in which the hammer grab 3, suspended by a crane, is reinserted into the casing 2 after the hard excavator 5 and table machine 4 in the casing tip excavation step S3 have been removed from the circumferential rotating device 1; a ground excavator restart step in which the ground excavator 3 is made to capture soil inside the casing 2; and a ground excavator re-excavation step in which the soil captured by the hammer grab is carried out of the casing 2. In the casing excavation step S2, the ground excavator re-insertion step, the ground excavator restart step, and the ground excavator re-excavation step are repeated to excavate to the required depth.

[0051] In the ground excavator re-insertion process, after the table machine 4 and hard excavator 5 are removed, the hammer grab 3 is reinserted into the casing 2. In the ground excavator restart process, soil and excavated material inside the casing 2 are captured. By re-excavating with the hammer grab 3, any residue inside the casing 2 generated in the casing tip excavation step S3 can be completely removed. In the ground excavator re-excavation process, the captured excavated material is carried out to the outside of the casing 2 and excavated. By repeating the ground excavator re-insertion process, the ground excavator restart process, and the ground excavator re-excavation process, excavation is carried out to the required depth.

[0052] In the finishing step S6, once the casing 2 has reached the planned depth through the re-excavation step S5, a reinforcing cage is inserted into the casing 2 and concrete is poured. The casing 2 may be used as is or it may be removed.

[0053] <Ground Excavation System> The ground excavation system D according to this embodiment is used in the so-called all-casing method, which is a ground excavation method S using the casing 2 as described above. As shown in Figures 2 to 5, the ground excavation system D comprises a full-circumference rotating device 1 for pressing in the casing 2, a hammer grab 3 for removing soil, rock fragments, etc. from inside the casing 2, a table machine 4 installed above the full-circumference rotating device 1, and a hard excavator 5 attached to the table machine 4.

[0054] As shown in Figures 6 to 8, the full-circumference rotating device 1 comprises a device body 11 installed on the ground, a first rotation mechanism 12 for rotating a cylindrical casing 2 at a constant speed and torque, and a pressing mechanism 13 for pushing the casing 2 in the vertical direction. The outer surface of the roughly cylindrical casing 2, which is long in the rotation axis direction (vertical longitudinal direction) of the full-circumference rotating device 1, is gripped inside the gripping hole of the full-circumference rotating device 1, and the casing 2 is pressed into the ground while rotating it around the entire circumference. The full-circumference rotating device 1 can adjust the rotation speed and pressing force according to the depth and ground conditions.

[0055] Casing 2 is a cylindrical steel pipe used to support the ground during excavation, as is commonly known. Its diameter varies depending on the ground conditions and pile dimensions, and its length can be extended according to the working depth. Casing 2 has a drilling blade (not shown) attached to its tip, allowing it to advance while cutting into the ground. Casing 2 may also be equipped with screw-type or flange-type joints for connecting multiple casings.

[0056] In this embodiment, the ground excavator 3 is a hammer grab, a device connected to a crane for collecting excavated material from the casing 2 and for removing the soil. It has dimensions smaller than the inner diameter of the casing 2 and has openable and closable claws (not shown) for capturing the ground and excavated material. The hammer grab also has a heavy hammer (not shown) for crushing hard ground, and can effectively crush the ground through vertical movement.

[0057] The table machine 4 is installed above the 360-degree rotating device 1. Specifically, a hollow cylindrical first joint (not shown) is provided at the top of the casing 2, and a hollow cylindrical second joint (not shown) corresponding to this joint is provided at the bottom of the table machine 4, with the first and second joints constituting the installation mechanism.

[0058] The table machine 4, which is mounted on the circumferential rotation device 1, is installed in such a way that it is rotatable relative to the circumferential rotation device 1, and the table machine 4 rotates (rotates on its own axis) due to the first rotation device of the circumferential rotation device 1.

[0059] Furthermore, by fitting the second joint into the first joint, the table machine 44 can be attached to the top of the casing 2. The second joint also serves as the reaction force support for the table machine 4.

[0060] The table machine 4 comprises a machine body 41, a connecting mechanism 42 to which a hard drilling machine 5 (described later) is connected, and a hard drilling machine displacement mechanism 43 that displaces the casing 2. The connecting mechanism 42 has a joint section (not shown) that rotatably fixes the body of the hard drilling machine 5 and connects it to the table machine 4, and a second rotation mechanism for rotating the hard drilling machine 5, allowing the connected hard drilling machine 5 to rotate (rotate).

[0061] The hard drilling machine displacement mechanism 43 includes a radial movement mechanism 44 that moves the hard drilling machine 5 radially outward from the casing 2. The radial movement mechanism 44 has a sliding frame, and by sliding the joint portion of the hard drilling machine 5 along the frame, the hard drilling machine 5 can be displaced outward from the center of the casing 2. The sliding of the hard drilling machine 5 may be done manually or automatically by a cylinder or motor.

[0062] The table machine 4 is rotatably mounted on the omnidirectional rotating device 1. By rotating (rotating) with the omnidirectional rotating device 1, the hard drilling machine 5, which has moved radially outward within the casing 2, rotates (revolves). By adjusting the radial movement amount of the radial movement mechanism 44 and the rotation amount of the omnidirectional rotating device 1, the hard drilling machine 5 can be moved to any position on the plane within the casing 2.

[0063] In this embodiment, the hard drilling machine 5 is a so-called down-the-hole hammer, designed to be smaller than the inner diameter of the casing 2 and capable of operating within the casing 2. The down-the-hole hammer has a hammer body with a piston (impacting body) built inside, which reciprocates using air pressure, and a bit made of high-hardness tungsten carbide or diamond-coated material provided at the tip of the hammer body.

[0064] The down-the-hole hammer rotates on its own axis due to the rotation of the table machine 4. The down-the-hole hammer is an impact drilling device that can be used to drill through hard rock G and ground using the impact of rotation and piston motion.

[0065] <Variations> In this embodiment, the tip drilling step was described in which a table machine 4 to which a hard drilling machine 5 is attached is installed on the 360-degree rotating device 1. However, the tip drilling step can be performed without using the table machine 4.

[0066] Specifically, as shown in Figure 9, the modified tip drilling step S3 includes a hard drilling machine installation step S131 (see Figure 9(A)) in which the hard drilling machine 5 is attached to the circumferential rotating device 1, a hard drilling machine displacement step S132 (see Figure 9(B)) in which the hard drilling machine attached to the circumferential rotating device is displaced from the center of the casing, and a hard rock drilling step S133 (see Figure 9(C)) in which the hard drilling machine 5 drills hard rock G or the like at the tip of the casing 2.

[0067] In this modified example, the hard drilling machine 5 is positioned above the circumferential rotation device 1, attached to an auger device (not shown) by a drilling device (not shown) such as an earth auger. The hard drilling machine 5 can move the auger device radially, and can also move circumferentially by rotating the circumferential rotation device 1.

[0068] In the modified tip drilling step S3, as shown in Figure 10, the hard drilling machine displacement step S132 includes a radial movement process in which the hard drilling machine 5 (see Figure 10(A)), which is mounted approximately at the center of the circumferential rotating device 1 casing 2, is moved radially outward from the center of the casing 2 (see Figure 10(B)), and a circumferential movement process in which the circumferential rotating device 1 is rotated, causing the hard drilling machine 5 mounted on the circumferential rotating device 1 to rotate (revolve) in an arc along the outer circumference of the casing 2 and move in the circumferential direction (see Figure 10(C)). Note that the intersection of the dashed-dotted line X and the dashed-dotted line Y in Figure 5 indicates the center of the casing 2.

[0069] In the hard drilling machine displacement process S132, the hard drilling machine 5 is displaced, allowing for concentrated drilling of a portion of the inner circumference of the tip of the casing 2. The radial and circumferential movement distances are adjusted according to the position of the hard rock mass G.

[0070] In the hard rock excavation process S133, the hard excavator 5 is rotated (rotated on its own axis) by, for example, an auger device to excavate the hard rock G or ground at the tip of the casing 2 and advance to the required depth. Subsequently, in the hard excavator removal process (not shown), after the excavation of the hard rock G is completed, the hard excavator 5 is removed from the 360-degree rotation device 1.

[0071] <Other variations> In this embodiment, the casing press-fitting step S1 was described in a form that includes a full-circumference rotating device installation step S11 in which the full-circumference rotating device 1 is installed in the ground. However, the full-circumference rotating device installation step S11 may be omitted, and the full-circumference rotating device 1 may be installed in advance.

[0072] In this embodiment, the casing press-fitting step S1 was described in which the tip of the casing 2 advances while scraping away the ground. However, the tip of the casing 2 may not have a scraping mechanism and may be directly pressed into the ground.

[0073] In this embodiment, the casing excavation step S2 was described in which a ground excavator 3 suspended by a crane is inserted into the casing 2. However, other lifting devices may be used instead of a crane.

[0074] In this embodiment, the ground excavator operation process S22 describes a configuration in which a hammer mechanism is used to break up a hard layer. However, a configuration in which excavation is performed using a mechanism other than a hammer mechanism is also possible.

[0075] In this embodiment, the casing tip drilling step S3 was described in which the hard drilling machine 5 is displaced outward from the center of the casing 2 during the displacement step. However, drilling may also be carried out along the central axis of the casing 2 without performing the displacement step.

[0076] In this embodiment, the casing tip drilling step S3 was described in which the table machine 4 is rotated by the all-around rotating device 1 and moves in an arc shape. However, in the casing tip drilling step S3, the hardening rotating machine may be moved linearly to a predetermined position.

[0077] In this embodiment, the casing tip drilling step S3 describes a configuration in which the hard drilling machine 5 is removed after the completion of drilling through the hard rock mass G. However, in the casing tip drilling step S3, the hard drilling machine 5 may not be removed, and drilling may proceed as is.

[0078] In this embodiment, the casing re-excavation step S5 describes a configuration in which the hard drilling machine 5 and table machine 4 used in the casing tip excavation step S3 are removed from the circumferential rotating device 1. However, it is also possible to continue excavating inside the casing 2 without removing the table machine 4.

[0079] In this embodiment, the finishing step S6 describes a configuration in which a reinforcing cage is inserted into the casing 2 and concrete is poured. However, a configuration in which concrete is directly filled without using a reinforcing cage is also possible.

[0080] In this embodiment, the hard drilling machine displacement mechanism 43 has been described in which the hard drilling machine 5 is moved within the casing 2 by the radial movement of the radial movement mechanism 44 and the rotation of the table machine 4 by the all-around rotation device 1. However, the hard drilling machine displacement mechanism 43 may also have a separate circumferential movement mechanism for moving the hard drilling machine 5 in the circumferential direction, and the hard drilling machine 5 may be moved within the casing 2 by the radial movement of the radial movement mechanism 44 and the circumferential movement of the circumferential movement mechanism.

[0081] Furthermore, the hard drilling machine displacement mechanism 43 may have, instead of the radial movement mechanism 44 and the circumferential movement mechanism, a vertical movement mechanism for moving the hard drilling machine 5 in a planar vertical direction and a lateral movement mechanism for moving it in a planar horizontal direction, thereby moving the hard drilling machine 5 within the casing 2 by the planar vertical movement of the vertical movement mechanism and the planar lateral movement of the lateral movement mechanism.

[0082] In this embodiment, the ground excavator 3 was described as a hammer grab. However, the ground excavator 3 may also be an auger drill or a bucket clamshell, as long as it can excavate and remove soil and other materials from inside the casing.

[0083] In this embodiment, the hard drilling machine was described as a down-the-hammer hole. However, the hard drilling machine may be other equipment such as a rotary drill or core drill, as long as it can drill through hard rock. [Industrial applicability]

[0084] This invention can be used in ground excavation methods and ground excavation systems. [Explanation of Symbols]

[0085] S: Ground excavation method S1: Casing press-fitting step S2: Casing drilling step S3: Casing tip drilling step S4: Casing re-pressing step S5: Re-excavation step inside the casing S6: Finishing step S11: Installation process for the full-circumference rotating device S12: Casing installation process S13: Casing press-fitting process S21: Ground excavator insertion process S22: Ground excavator operation process S23: Soil removal process using a ground excavator S31: Table machine installation process S32: Hard drilling machine installation process S33: Hard drilling machine displacement process S34: Hard rock excavation process S131: Hard drilling machine installation process S132: Hard drilling machine displacement process S133: Hard rock excavation process 1: Full rotation device 2: Casing 3: Ground excavator (hammer grab) 4: Table Machine 5: Hard drilling machine 11: Main unit of the device 12: First Rotation Mechanism 13: Pressing mechanism 41: Machine body 42: Connection mechanism 43: Hard excavator displacement mechanism 44: Radial movement mechanism D: Ground excavation system G: Hard bedrock X: dash-dotted line Y: Dot-dashed line

Claims

1. A casing press-fitting step in which a cylindrical casing is pressed in while being rotated by a full-circumference rotating device, The casing includes, if hard rock is present at the tip of the casing during the casing press-fitting step, a casing tip drilling step in which the hard rock at the tip of the casing is drilled. The aforementioned casing tip drilling step is, A table machine installation step involves installing a table machine, on which a hard drilling machine for drilling the hard rock mass can be operably mounted, into the 360-degree rotating device. Following the table machine installation step, a hard drilling machine displacement step is performed to displace the hard drilling machine installed on the table machine from the center of the casing. A ground excavation method comprising, after the hard excavator displacement step, a hard rock excavation step of excavating the hard rock mass with the hard excavator.

2. The ground excavation method according to claim 1, wherein the excavator displacement step includes a radial movement process that moves the rigid excavator radially outward from the casing.

3. The ground excavation method according to claim 2, wherein the excavator displacement step includes a circumferential movement process in which the rigid excavator is rotated in an arc shape along the outer circumference of the casing and moved in the circumferential direction.

4. The ground excavation method according to claim 3, wherein the circumferential movement process rotates the table machine by rotating the all-around rotating device, and moves the hard excavator attached to the table machine in the circumferential direction.

5. A ground excavation method according to any one of claims 1 to 4, comprising a casing excavation step of excavating inside the casing after the casing press-in step and before the casing tip excavation step.

6. A full-circumference rotating device that rotates and press-fits a cylindrical casing, A table machine installed above the aforementioned 360-degree rotating device, The table machine is equipped with a hard drilling machine that is attached to the table machine and moves through the casing to excavate the tip of the casing. The aforementioned table machine is A ground excavation system comprising a hard excavator displacement mechanism for displacing the hard excavator relative to the casing.

7. The ground excavation system according to claim 6, wherein the hard excavator displacement mechanism comprises a radial movement mechanism for moving the hard excavator radially outward from the casing.

8. The ground excavation system according to claim 7, wherein the radial movement mechanism moves the hard excavator radially outward by a predetermined distance.

9. The ground excavation system according to claim 7, wherein the all-around rotating device is equipped with an installation mechanism that allows the table machine to be rotatably mounted.

10. The ground excavation system according to any one of claims 6 to 9, wherein the hard excavator is rotated by a table machine to excavate the hard rock mass at the tip of the casing.

11. A casing press-fitting step in which a cylindrical casing is pressed in while being rotated by a full-circumference rotating device, The casing includes, if hard rock is present at the tip of the casing during the casing press-fitting step, a casing tip drilling step in which the hard rock at the tip of the casing is drilled. The aforementioned casing tip drilling step is, The hard drilling machine installation process involves attaching the hard drilling machine to a 360-degree rotating device, Following the hard drilling machine installation step, a hard drilling machine displacement step is performed to displace the hard drilling machine, which is attached to the all-around rotating device, from the center of the casing. A ground excavation method comprising, after the hard excavator displacement step, a hard rock excavation step of excavating the hard rock mass with the hard excavator.

12. A full-circumference rotating device that rotates and press-fits a cylindrical casing, The device comprises a hard excavator attached to the aforementioned full-circumference rotating device, The hard drilling machine is mounted on a circumferential rotating device so as to be movable in the radial direction of the casing. Furthermore, the ground excavation system moves in the circumferential direction as the aforementioned all-around rotating device rotates.

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