JPH0972183A - Excavation method and excavator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the excavation of a shaft with large caliber and great depth by pouring lubricant supplied from a channel provided to a side wall of a casing during the excavation between the circumferential surface of the casing from a required part on the circumferential surface of the front end of the casing and excavated wall surface. SOLUTION: A following casing 5 connecting an antecedent casing 2 to a ring joint 4 is driven into the ground by a full-swivel type casing rotary press-in machine to excavate, and when the length of an excavated hole becomes deep to a certain extent, earth pressure applied to the circumferential surface of the casing 5 is suddenly increased to increase the circumferential frictional resistance, and the press-in machine is in an incapable state. Then, lubricant led to a ring-shaped space section 16 of the casing 5 on the upper stage is sent to the space section 16 from a linked hole 18 of the lower end casing 15 through a linked hole 17 of the casing 5 on the lower stage, it is led to the inside of an internal passage 21 of the ring joint 4 through a linked hole 20 from the linked hole 18, it is extracted from an extraction outlet 22, and the circumferential frictional resistance is reduced to stat the driving of the casing rotary press-in machine again.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is used to excavate the ground and excavate a large-diameter and deep-deep vertical hole when constructing cast-in-place concrete piles associated with foundation works such as building foundations and bridge foundations. The present invention relates to a ground excavation method and excavation equipment.

[0002]

2. Description of the Related Art Conventionally, in order to excavate a vertical hole for forming a cast-in-place concrete pile, a full-swivel vertical excavator is used to press the soil into the ground while rotating the casing to remove the earth and sand inside the casing. A method of excavating while discharging with a hammer grab is widely practiced.

[0003]

In the excavation using the above-described full swing vertical excavator, the longer the length of the hole and the larger the hole diameter, the more the peripheral pressure applied to the casing by the ground soil pressure. The friction resistance of the casing peripheral surface becomes large. However, in the case of a relatively small bore diameter of around 1000 mm, even if the bore length is considerably long, the casing circumferential surface friction resistance does not become a problem, but the bore diameter is 2
In the case of a large diameter of 000 to 3000 mm, when the drill hole length exceeds, for example, 10 m, the earth pressure applied to the outer peripheral surface of the casing abruptly increases and the peripheral frictional resistance thereof becomes abnormally high. Press-fitting does not proceed,
It cannot be pushed in and out by rotation, which makes it impossible to construct.

In view of the above problems, the present invention reduces excessive circumferential frictional resistance applied to the casing during excavation at a large diameter and a large depth, thereby making it possible to easily excavate a large diameter and a large depth vertical hole. An object of the present invention is to provide an excavation method and an excavation device that can significantly improve the construction efficiency.

[0005]

According to a first aspect of the present invention, there is provided a method for excavating a casing having an excavating blade at a tip thereof, which is press-fitted into the ground while being rotated by a casing rotary press-fitting machine to discharge earth and sand inside the casing. In the excavation method of excavating the ground while performing the excavation, the lubricant supplied from the flow path formed in the side wall of the casing is supplied from the required portion of the outer peripheral surface of the casing to the outer peripheral surface of the casing and wall surface It was designed to be poured out between and.

A second aspect of the present invention is the excavation method according to the first aspect, wherein the casing is rotated and vertically moved while pouring out the lubricant.

The excavating device according to a third aspect of the invention is connected to the casing rotary press-fitting machine 1, the preceding casing 2 having the excavating blade 3, the ring joint 4 connected to the preceding casing 2, the ring joint 4 and being connectable to each other. A plurality of subsequent casings 5 and a swivel device 6 detachably attached to the rearmost rearmost casing 5, and the sidewalls of the respective subsequent casings 5 can communicate with each other in a state where the subsequent casings 5 are connected to each other. A flow channel is provided, and the ring joint 4 is provided with a spout 22 that is connectable to the flow channel of the subsequent casing 5 connected to the ring joint 4 so that the spout 22 is open to the outer peripheral surface. A check valve 23 is provided, and the lubricant is pressurized and supplied to the flow path of the rearmost casing 5 at the rear end through the swivel device 6. That.

According to a fourth aspect of the present invention, in the excavating device according to the third aspect, the check valve 23 includes a valve hole 28 provided between the internal passage 21 of the ring joint 4 and the spout 22. A valve shaft 29 having a diameter smaller than the inner diameter of the valve hole 28 and longer than the hole length of the valve hole 28, and a valve shaft 29 projecting from the outer end of the valve shaft 29 so as to be positioned inside the spout 22, and the valve hole 29 A valve body 30 for closing the valve 28, and a retaining piece radially provided on the inner end of the valve shaft 29 and abutting against the inner end surface of the valve hole 28 so as to retain the valve body 30 in the open position. It consists of 31 and
The valve body 3 is caused by the pressure of the lubricant introduced into the internal passage 21.
0 is open against earth pressure.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an excavating device according to the present invention, in which 1 is a fully swiveling casing rotary press-fitting machine, 2 is a preceding casing having an excavating blade 3, and 4 is a preceding casing 2. Is a ring joint connected to. Reference numeral 5 denotes a plurality of subsequent casings that are detachably connected to the ring joint 4 and can be connected to each other. Reference numeral 6 denotes a swivel device that is detachably attached to the rearmost casing 5 (the uppermost end). The fully swiveling casing rotary press-fitting machine 1 has a well-known structure which has been conventionally used, and the casing 5 is penetrated into the central portion of the machine frame 7,
While the outer peripheral surface of the casing 5 is gripped by the chuck 8 and rotated by a hydraulic motor (not shown), the casing 5 is press-fitted and withdrawn by a hydraulic cylinder 9 for press-fitting and withdrawing. Further, in FIG. 1, 10, a grout mixer used when pouring grout for forming a concrete pile, 11 is a mortar pump connected to this mixer 10, and the pump 11 is connected to the swivel device 6 via a hose 12. To be done.

2 and 3 are enlarged detailed vertical sectional views of the preceding casing 3, the ring joint 4 and each succeeding casing 5, and FIGS. 4 and 5 are transverse sectional views of the succeeding casing 5, respectively. As you can see from these figures,
Each subsequent casing 5 includes an inner tubular member 13a, an outer tubular member 13b having a diameter slightly larger than the inner tubular member 13a, and both tubular members 13a, 1a.
A casing body 13 composed of a plurality of reinforcing members 13c interposed in an annular space 16 between 3b at required circumferential intervals.
And an upper end casing part 14 integrally connected by welding to the upper end of the casing body 13, and a lower end casing part 15 similarly integrally connected by welding to the lower end of the casing body 13, and the upper end Casing part 14
Is formed with a connecting male portion 14a, the lower end casing portion 15 is formed with a connecting female portion 15a, and the upper and lower casing portions 14, 15 are provided with communication holes 17, 18 at intervals of 45 degrees in the circumferential direction. They are laid vertically one by one. The annular space portion 16 between the inner and outer tubular members 13a and 13b of the casing body 13 has a plurality of reinforcing members 13 as shown in FIG.
The small spaces 16a are partitioned by c and are divided into a plurality of small spaces 16a. The small spaces 16a are communicated with each other by, for example, providing a lateral hole in the reinforcing member 13c.

When connecting the succeeding casings 5 to each other, however, as shown in FIG. 2, for example, the connecting male portion 1 of the upper end casing portion 14 of the lower succeeding casing 5 is connected.
4a includes a lower end casing portion 1 of the upper-stage side subsequent casing 5
5 is engaged with the connecting female portion 15a, and the lower end casing portion 1 and the communication hole 17 of the upper end casing portion 14 are engaged.
5 so that the communication holes 18 of the connection member 5 overlap with each other, and in such a state, a plurality of joint pins 19 (see FIG. 1 and FIG. 5) are passed through the connecting male portion 14a and the connecting female portion 15a to connect them. Good. By joining the two casings 5 and 5 in this manner, the annular space portions 16 and 1 of the two casings 5 and 5 are joined together.
6 are communicated with each other through the communication holes 17 and 18.

Further, as shown in FIG. 2, the ring joint 4 is made of a cylindrical body having the same thickness as the subsequent casing 5, and the upper end portion thereof has a female portion 15a for connection of the subsequent casing 5.
A connecting male portion 4a that engages with the connecting male portion 4a is formed at the lower end portion, and a connecting female portion 4b that engages with the connecting male portion 2a provided in the preceding casing 2 is formed. Further, the communication hole 18 of the succeeding casing 5 is provided on the upper end side of the ring joint 4.
A communication hole 20 is provided at a position corresponding to
0 communicates with the internal passage 21 of the ring joint 4 (located directly below the communication hole 20), and the internal passage 21
Is a spout 22 that opens to the outer peripheral surface of the ring joint 4.
Leads to. The spout 22 has the communication holes 17, 1
Similar to Nos. 8 and 20, check valves 23 are provided at four positions at intervals of 45 degrees in the circumferential direction of the ring joint 4, and each spout 22 is provided with a check valve 23.

The ring joint 4 and the subsequent casing 5 are connected to each other by connecting male portion 4a on the ring joint 4 side.
And the female part 15a for connection on the side of the subsequent casing 5 are engaged with each other, and the communication hole 18 on the side of the subsequent casing 5 and the communication hole 20 on the side of the ring joint 4 are overlapped with each other so that a joint is formed between both engagement parts. The pin 19 (see FIG. 1) may be passed through, and the ring joint 4 and the preceding casing 2 may be connected by the female portion 4b for connection on the ring joint 4 side.
And the connecting male portion 2a on the side of the preceding casing 2 are engaged with each other, and joint pins (not shown) similar to the above are provided on both engaging portions.
You only have to penetrate. Therefore, ring joint 4
And the subsequent casing 5 are connected, the subsequent casing 5
Of the annular space 16 and the internal passage 21 of the ring joint 4
And are communicated with each other through the communication holes 18 and 20.

As shown in FIGS. 1 and 3, the swivel device 6 introduces the liquid (lubricant) pumped from the pump 11 by the hose 12 into the annular space 16 of the rotating subsequent casing 5. As shown in FIG. 3, a mounting portion 24 that is detachably attached to the connecting male portion 14a of the rearmost casing (uppermost stage) of the subsequent casing 5 and is rotatably mounted thereto, and a hose as shown in FIG. The mounting portion 24 has an annular groove 26 formed in the flange portion 24a that engages with the connecting male portion 14a of the subsequent casing 5 in a relatively rotatable manner. 26
Communicate with a liquid passage 27 extending from the inside of the main body 25. Then, the lubricant that is pressure-fed from the inside of the main body portion 25 through the liquid passage 27 to the annular groove 26 is
6 is introduced into the annular space 16 in the casing 5 through the communication hole 17 in the upper casing 14 of the subsequent casing 5.

The lubricant introduced into the annular space 16 of the rearmost end (uppermost stage) of the subsequent casing 5 as described above passes from the communication hole 18 of the lower end casing portion 15 thereof to the communication hole 17 of the subsequent casing 5 on the lower stage side. Through the communication hole 18 of the lower end casing portion 15 through the communication hole 20 into the internal passage 21 of the ring joint 4 and the spout 22 It will be ejected outside.

As shown in detail in FIGS. 6 and 7, the check valve 23 has a valve hole 28 provided between the internal passage 21 and the spout 22 of the ring joint 4, and the valve hole 28. A valve shaft 29 having a diameter smaller than the inner diameter and longer than the hole length of the valve hole 28;
A valve body 30 which is provided on the outer end of the valve shaft 29 so as to be located in the spout 22 and closes the valve hole 28 by earth pressure;
The valve shaft 30 is provided radially at the inner end of the valve shaft 29 so as to project radially.
Is held at the valve open position, and a holding portion piece 31 is brought into contact with the inner end surface of the valve hole 28. Therefore, when the pressurized lubricant is not introduced into the internal passage 21 of the ring joint 4 during use in the excavator, the valve element 30 is moved by the earth pressure of the ground around the ring joint 4 as shown in (A) of FIG. In the state shown in (), the valve hole 28 is closed by being pressed against the outer end of the valve hole 28, so that the sediment does not enter the valve hole 28. When the pressurized lubricant is introduced into the internal passage 21 of the ring joint 4, the pressure of the lubricant causes the valve body 30 to open against earth pressure as shown in FIG. 6B. It has become. In FIG. 7A,
Drawing which looked at valve body 30 from the outside of valve hole 28, (B) of the same figure
[FIG. 3] is a view of the valve body 30 as viewed from the inside of the valve hole 28.

According to the check valve 23 having such a structure, the valve body 30 in the spout 22 is moved in the axial direction by the pressure of the lubricant from the internal passage 21 of the ring joint 4 and the earth pressure of the surrounding ground. Since the valve hole 28 is opened and closed, the valve body is structurally robust and has excellent durability as compared with the conventional check valve in which the valve body is a hinge type, and the opening and closing operation is quick. Can be done reliably.

The above-mentioned lubricant is a mixture of water, bentonite and a thickening wall-forming agent (conditioning agent), and a preferable lubricant is 1000 kg of water to which 50 kg of bentonite and 2 kg of thickening wall-forming agent are added. Good. This lubricant is shown in Figure 1.
Mix by the grout mixer 10 shown in FIG. Also,
In the above excavator, the length of the preceding casing 2 is 1
m, the length of the ring joint 4 is 2 m, the length of the succeeding casing 5 is 5 m, and their outer diameter is 3000 mm.
And

An excavation method using the excavation device having the above-described structure will be described with reference to FIG.
First, as shown in FIG. 7 (A), the first succeeding casing 5 to which the preceding casing 2 and the ring joint 4 are connected is press-fitted into the ground while being rotated (normal rotation) by the full-swivel type casing rotary press-fitting machine 1. And this subsequent casing 5
After press-fitting to a certain extent, the earth and sand inside the casing 5 are excavated by the hammer grab 32, and the earth is discharged. After the press-fitting and excavating and discharging soil are repeated to finish the drilling by the first succeeding casing 5, as shown in FIG.
Then, the same press-fitting and excavation and earth removal are continued. It should be noted that the first casing 5 digs up to about 7 to 8 m.

As shown in FIG. 7B, when the second succeeding casing 5 is press-fitted and the hole length reaches, for example, about 10 m, the earth pressure P applied to the outer peripheral surface of the casing 5 rapidly increases. Then, the peripheral frictional resistance becomes abnormally large and the press-fitting is impossible. In such a state, or at a stage slightly before that, the drive of the full-swivel type casing rotary press-fitting machine 1 is temporarily stopped, and (C) in the same figure is provided at the upper end of the succeeding casing 5 at the upper stage (the last end). The swivel device 6 is attached as shown in FIG. Then, the lubricant mixed by the grout mixer 10 is pumped by the pump 11,
The swivel device 6 is supplied under pressure from a mounting portion 24 of the swivel device 6 to a series of passages extending from the upper casing 5 to the lower casing 5 and the ring joint 4, and is discharged from each spout 22 on the outer peripheral surface of the ring joint 4. In this way, while pouring out the lubricant from each pouring port 22, the drive of the fully swiveling casing rotary press-fitting machine 1 is restarted to rotate the succeeding casing 5 and vertically move a predetermined stroke.

Each spout 22 on the outer peripheral surface of the ring joint 4
The lubricant poured out from the front casing 2 as shown in FIG. 7 (C) as the rear casing 5 rotates and moves up and down.
It sufficiently penetrates into the gap between the outer peripheral surface and the outer peripheral surface of the succeeding casing 5 and the wall surface of the borehole, and improves the sliding between the outer peripheral surface of the casing and the wall surface of the borehole to reduce the frictional resistance of the casing peripheral surface.
As described above, since the frictional resistance of the casing peripheral surface is reduced by the pouring of the lubricant, it is possible to easily carry out the work of boring a hole having a large diameter of 3000 mm up to a large depth of several tens of meters. While pouring the lubricant, the casing 5
It may be rotated and press-fitted as it is, but the casing 5
By rotating the above as described above and moving it up and down by a predetermined stroke, the lubricant can be widely spread in the gap between the casing 5 and the hole wall, and the casing circumferential surface friction resistance can be reduced more effectively. .

Further, in the above-described excavating device of the present invention, the spout 22 through which the lubricant is spouted is not provided in the preceding casing 2 or the succeeding casing 5, but the outer peripheral pressure acts most and the peripheral frictional resistance is large. Since the ring joint 4 is provided, for example, 2 to 3 m above the tip of the excavating blade 3, the casing circumferential surface friction resistance can be reduced more effectively, and the preceding casing 2 and the following casing 5
It is advantageous in terms of manufacturing as compared with the case where

Further, a flow path for supplying a lubricant is provided on the side wall of each succeeding casing 5 so as to be able to communicate with each other while the succeeding casings 5 are connected to each other, and the flow path of each succeeding casing 5 is poured. Since it can be connected to the outlet 22, no special piping is required, and the mutual connection of the flow paths becomes simple. In particular, since the flow path of each succeeding casing 5 uses the annular space 16 formed in the casing body 13 of the succeeding casing 5 and the communication holes 17 and 18 are provided therein, the flow path is formed. Is easy. Also,
Since the check valve 23 is provided at the pouring port 22, soil or the like does not enter the pouring port 22 during excavation work. Also,
Since the swivel device 6 is used to pressurize and supply the lubricant to the flow path of the trailing casing 5 at the rearmost end, the lubricant can be supplied while the casing 5 is rotated, and the swivel device 6 can also supply the lubricant. Since it can be attached and detached, it may be attached only when the lubricant is supplied. Further, since the lubricant is mixed by the mixer 10 used for pouring grout and is pressure-fed to the casing side by the mortar pump 11 connected to the mixer 10, it is special for mixing and pressure-feeding the lubricant. Unnecessary equipment is unnecessary.

[0024]

According to the excavating method according to the first aspect of the present invention, during excavation, the lubricant supplied from the flow path formed in the casing side wall is supplied to the casing outer peripheral surface and the excavation hole from the front end side outer peripheral surface required portion of the casing. By pouring between the walls,
It is possible to improve the sliding between the outer peripheral portion of the casing and the wall surface of the hole and reduce the frictional resistance of the outer peripheral surface of the casing. Therefore, with a large diameter of 2000-3000 mm,
This makes it possible to easily carry out excavation work for large-diameter, deep-deep vertical holes with a length of several tens of meters.

According to claim 2, while pouring out the lubricant,
By rotating the casing and moving the casing up and down by a predetermined stroke, the lubricant can sufficiently spread in the gap between the casing and the side wall of the hole, and the casing circumferential surface friction resistance can be more effectively reduced.

By using the excavating device according to the third aspect, it is possible to easily carry out excavation work for a large-diameter, large-depth vertical hole. Particularly, according to this drilling device, the spout for pouring the lubricant is not provided in the preceding casing or the succeeding casing, but the ring joint from the tip of the excavating blade, which has the largest outer peripheral pressure and the large frictional resistance on the peripheral surface. Since it is provided in a part, the frictional resistance on the casing peripheral surface can be effectively reduced, and the production becomes easier as compared with the case where it is provided in the preceding casing or the succeeding casing.

Further, a flow path for supplying a lubricant is provided on the side wall of each succeeding casing so as to be able to communicate with each other while the succeeding casings are connected to each other, and the flow path of each succeeding casing is connected to the spout. Since this is possible, no special piping is required and the flow paths can be easily connected to each other. Further, since the check valve is provided at the spout, soil and sand will not enter the spout during excavation work. In addition, since the swivel device is used to pressurize and supply the lubricant to the flow path of the subsequent casing at the rearmost end, the lubricant can be supplied while rotating the casing, and the swivel device is detachable from the subsequent casing. Since it is possible, it is necessary to mount it only when the lubricant is supplied.

According to the fourth aspect, the valve body in the pouring port is moved in the axial direction by the pressure of the lubricant from the internal passage of the ring joint and the earth pressure of the surrounding ground to open and close the valve hole. Therefore, compared with the conventional check valve in which the valve body is a hinge type, it is structurally robust and has excellent durability, and the opening / closing operation can be performed quickly and reliably.

[Brief description of drawings]

FIG. 1 is an overall side view of an excavation device according to the present invention.

FIG. 2 is an enlarged vertical sectional view of a casing.

FIG. 3 is an enlarged vertical sectional view showing how the swivel device is attached to the casing.

FIG. 4 is an enlarged sectional view taken along line XX of FIG. 1;

5 is a cross-sectional view taken along line YY of FIG.

FIG. 6 is a vertical cross-sectional view showing a check valve, (A) showing a closed state, and (B) showing an open state.

FIG. 7A is a front view of the check valve as viewed from the outside of the valve hole, and FIG. 7B is a front view of the check valve as viewed from the inside of the valve hole.

8 (A) to (C) are explanatory views sequentially explaining an excavation process.

[Explanation of symbols]

 1 Full swivel type casing rotary press-fitting machine 2 Preceding casing 3 Drilling blade 4 Ring joint 5 Subsequent casing 6 Swivel device 22 Lubricant spout 23 Check valve 24 Swivel device 28 Valve hole 29 Valve shaft 30 Valve body 31 Holding piece

Claims (4)

[Claims] 1. A method for excavating the ground, wherein a casing equipped with an excavating blade at its tip is pressed into the ground while being rotated by a casing rotary press-fitting machine, and earth and sand are discharged while the inside of the casing is discharged. An excavation method in which a lubricant supplied from a flow path formed on a side wall of the casing is poured out from a required portion on the outer peripheral surface on the tip end side of the casing between the outer peripheral surface of the casing and the wall surface of the borehole along the way. 2. The excavation method according to claim 1, wherein the casing is rotated and vertically moved while pouring out the lubricant. 3. A casing rotary press-fitting machine, a leading casing having an excavating blade, a ring joint connected to the leading casing, a plurality of trailing casings connected to the ring joint and connectable to each other, and a trailingmost trailing casing. It consists of a swivel device that is detachably attached,
The side wall of each of the succeeding casings is provided with a flow path that can communicate with each other while the succeeding casings are connected to each other, and the ring joint is connectable to the flow path of the succeeding casing connected to the ring joint. The excavator is provided so that the outlet is opened to the outer peripheral surface, the check valve is provided at the outlet, and the lubricant is pressurized and supplied to the flow path of the subsequent casing at the rearmost end through the swivel device. apparatus. 4. The check valve includes a valve hole provided between an internal passage of the ring joint and the spout, and a diameter smaller than an inner diameter of the valve hole and longer than a hole length of the valve hole. A valve shaft, a valve body projecting at an outer end of the valve shaft so as to be located in the pouring port, and closing a valve hole by earth pressure, and a valve body radially projecting at an inner end of the valve shaft. A holding part that abuts the inner end surface of the valve hole so as to hold the body in the open position, and the pressure of the lubricant introduced into the internal passage opens the valve body against earth pressure. The excavation rig according to claim 3, wherein