JPH07158059A - Soil excavation method - Google Patents

Abstract

PURPOSE:To efficiently form a thin excavated channel. CONSTITUTION:An impact and torque are concurrently applied to a drilling bit and circular drilled holes a1 to a3 are formed in advance (1st process). Thereafter, a channel-like drilled holes b1 and b2 are formed in continuous state among the holes a1 and a3, due to the reciprocal motion of a plate type drilling bit (2nd process). The holes b1 and b2 are channel-like drilled holes thinner than the diameter of the holes a1 and a3, and have end sections continuous thereto. When the holes a1 to a3, and b1 and b2 are formed up to the prescribed depth, the first and second processes are sequentially repeated, using the end circular hole a3 as a guide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground excavation method, and more particularly to an excavation method capable of excavating and forming a thin excavation groove in the ground where gravel and the like are mixed.

[0002]

2. Description of the Related Art Soil retaining walls for constructing underground structures,
The underground continuous wall construction method is known as a construction method for constructing a water blocking wall provided around a dam or a waste treatment plant. In this type of underground continuous wall method, a rectangular excavation groove is excavated from the ground surface to a predetermined depth, and a hardened material such as concrete is filled in the excavation groove to form a panel-shaped unit wall body.

Then, by repeating these steps in sequence, the unit wall bodies are sequentially connected laterally to form a continuous underground wall in the ground. by the way,
In such a construction method, it is necessary to excavate a rectangular excavation groove in the ground, and as a ground excavation device used for forming such an excavation groove, for example, a grab-type excavation device or a rotary cutter is used. The drilling rig used was usually adopted.

However, the method of forming the excavation groove using such an excavation device has the following technical problems.

[0005]

That is, the underground wall constructed by the underground continuous wall construction method as described above, except when it is used as a part of the main body, is It is only necessary to have the required wall strength, but it is difficult to excavate a comparatively thin excavation groove with a conventional grab-type excavator or an excavator that uses a rotary cutter,
Even if it is possible to excavate a thin excavation groove to some extent by miniaturizing these excavation devices, for example, it is very difficult to excavate a thin excavation groove in the ground where gravel is mixed,
It was almost impossible.

[0006] Further, when forming an underground wall in the form of a column pile,
A ground excavating device in which a plurality of cylindrical excavating bits are arranged in a straight line is also provided.However, in such a type of ground excavating device, if the diameter of the excavating bit is made small and an impact force applying device is used, gravel Although it is possible to form excavation trenches with a relatively thin thickness in the ground where there are mixed, but if a large number of small-diameter cylindrical excavation bits are arranged in a row, the configuration becomes complicated and the number of arrangements is limited. There is also a problem that the length of the groove formed by excavation is shortened and the excavation efficiency is reduced.

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a ground excavation method capable of efficiently excavating and forming an excavation groove having a thin thickness. It is in.

[0008]

In order to achieve the above object, the present invention is to form a groove-like excavation hole in the ground and fill the inside of the excavation hole with a curable mud to cure it. In a ground excavation method for forming a wall in the ground, a first step of forming a plurality of circular drill holes at predetermined intervals in the ground by rotating the bit while applying an impact, and the circular shape A second step of forming a groove-shaped drilling hole having a thickness smaller than the diameter of the circular drilled hole between the drilled holes to a predetermined depth by reciprocating the plate-shaped drilling bit while applying an impact; After the drill hole is formed to a predetermined depth, the first and second steps are sequentially repeated using the circular drill hole located at the end as a guide.

[0009]

According to the ground excavation method having the above-described structure, the groove-shaped excavation hole having a thickness smaller than the diameter of the circular excavation is continuously formed between the plurality of circular excavation holes. At this time, since an impact force is applied when forming the circular and ditch-shaped excavation holes, even in the ground where gravel is mixed, the impact force can crush the gravel.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. 1 to 4 show an example of a ground excavation device used in a ground excavation method according to the present invention. The ground excavation device shown in the figure is mounted on a caterpillar type work vehicle 10, and the work vehicle 10 is
Swing arm 12 driven by cylinder and tilting cylinder 1
4 is provided, and a holding plate 16 is mounted and supported between the swing arm 12 and the tilting cylinder 14.

On the front side of the holding plate 16, three columns 18 are fixedly installed at a predetermined interval in the vertical direction. A connecting member 20 that connects the columns 18 is provided on the lower end side of the columns 18, and the connecting member 20 is provided with an outrigger 22 for adjusting the bottoming position on the ground surface. A rod breaker 24 and a rod holder 26 are arranged near the lower ends of the columns 18, respectively.

Further, a percussion head (impact applying device) 28 and a rotation driving device 3 are provided on the upper end side of each column 18.
0 and 0 are arranged respectively. Further, a feeding device 32 for pulling out the ground excavation device is arranged at the upper end of each of the columns 18. Percussion head 28
Has a hydraulically driven piston inside,
An impact force can be obtained by moving the piston up and down.

Further, as the rotary drive device 30, for example, a motor of a hydraulic drive type is used. The excavation bit portion 34, which is a main member of the ground excavation device of this embodiment, is arranged on the lower end side of the percussion head 28, and its details are shown in FIGS. The excavation bit section 34 shown in the figure includes left and right and center excavation bits 36, 3
It is roughly composed of a cylindrical one composed of 8 and 40 and a pair of left and right plate-shaped excavating bits 42 and 44 provided between the excavating bits 36, 38 and 40.

Cylindrical left and right and center drilling bits 36,
38 and 40 are arranged on the front side of the column 18, the upper end of which is attached to the lower end of the percussion head 28, and the lower end of which is supported by the rod holder 26. , An impact force is applied from the upper end side by a percussion head (impact application device) 26, and rotation is given by a rotation drive device 28, and the interval between the excavating bits 36, 38, 40 is the same as the arrangement interval of the columns 18. It has become.

Left and right and center drill bits 36, 38, 4
0 is the tip, middle and upper end cylinders 361, 381, 401, 362, 382, 4 screwed or fixed to each other.
02, 363, 383, 403, and inside thereof, hole portions 364, 384, 404 penetrating in the axial direction are provided, and in the hole portions 364, 384, 404, when excavating the ground, Bentonite mud is supplied to ensure the stability of the excavated hole wall.

Bit blades 365, 385, 405 are provided on the outer circumferences of the tips of the respective tip cylinders 361, 381, 401.
Is fixed, and each tip cylinder 361, 38
On the upper end side of 1,401, bit blades 365, 385, 4
The first expanded portion 366, 38 having a diameter slightly smaller than the diameter of 05.
6, 406 are formed respectively. Further, in this embodiment, the intermediate cylindrical body 362 of the left and right excavating bits 36, 38 is
382 has a shorter overall length than the intermediate tubular body 402 of the center drilling bit 40, and each upper end tubular body 363, 3
At the lower ends of 83 and 403, the first expanded diameter portions 366 and 38 are provided.
Second expanded portion 3 having a truncated cone shape having the same diameter as 6, 406
67, 387 and 407 are formed respectively.

Further, the intermediate cylindrical body 4 of the center drilling bit 40.
A pair of substantially elliptical cams 408 projecting in the same radial direction are integrally formed on the upper and lower ends of 02. on the other hand,
The left and right plate-shaped excavating bits 42 and 44 include substrates 421 and 441 formed in a substantially triangular shape, and a pair of hollow cylinder-shaped left and right sleeves 422 fixed to the outer ends of the substrates 421 and 441.
442, a hollow cylindrical central sleeve 423 fixedly provided so as to straddle the inner ends of the substrates 421, 441, and a plurality of bit pieces 4 fixedly provided at the lower ends of the substrates 421, 441.
24 and 444.

The left and right sleeves 422 and 442 are fitted on the outer circumferences of the intermediate cylinders 362 and 382 of the left and right excavation bits 36 and 38, respectively, and the tip and the top cylinder 36 are attached to the upper and lower ends thereof.
1,381,363,383 first and second expanded diameter portions 3
66, 386, 367, 387 are abutted so as to be scissored, and this abutting portion is provided between the left and right excavating bits 36, 38 to the left and right plate-like excavating bits 42, 44.
An impact force transmitting portion A that transmits the impact force from

The left and right sleeves 422 and 442 are formed with long holes 425 and 445, respectively, on the central axes of which the long axes are located in the plane direction of the substrates 421 and 441. Further, the central sleeve 423 is provided with the central drill bit 40.
Of the intermediate cylindrical body 402, and the first and second expanded diameter portions 406 and 407 of the tip and upper end cylindrical bodies 401 and 403 are abutted to the upper and lower ends of the intermediate cylindrical body 402 so as to scissor. , Center drill bit 40 to left and right plate-shaped drill bit 42,
An impact force transmission portion A that transmits the impact force from the percussion head 28 is formed at 44.

The central sleeve 423 has a substantially elliptical shape in which the major axis side is located on the central axis in the thickness direction of the bit pieces 424 and 444 and the minor axis side is located in the longitudinal direction of the bit pieces 424 and 444. The cam surface 426 is formed so as to penetrate therethrough. As shown in the cross section of FIG. 4, the cam surface 426 is set such that the length on the major axis side is slightly larger than the length of the cam 408 and the length on the minor axis side is substantially the same as the length of the cam 408. .
The cam surface 426 engages with the cam 408 to convert the rotational force applied to the central excavation bit 40 from the rotary drive device 30 into a reciprocating movement to produce the left and right plate-shaped excavation bits 42, 44.
And a moving direction conversion unit B that transmits the

It should be noted that the cam surface 426 is formed by the central sleeve 42.
3 does not need to be provided over the entire length, and, for example, the cam 40
It is also possible to form only in the range that can be engaged with 8.
Further, in the present embodiment, the thickness of the left and right plate-shaped excavating bits 42, 44 including the substrates 421, 441 and the bit pieces 424, 444 has a cylindrical shape.
It is set smaller than the diameter of 40.

Further, a plurality of bit pieces 424, 444
Are located above the tips of the cylindrical drill bits 36, 38, 40, and each has a length of the plate drill bit 4
2 and 44 have substantially the same length as a reciprocating stroke 1 to be described later, and the mountain portions of the bit pieces 424 and 444 are arranged so as to be orthogonal to each other at the adjacent portions along the longitudinal direction. In this case, the peak portions of the bit pieces 424 and 444 do not necessarily need to be arranged orthogonally, and may intersect at a predetermined angle, for example.

Further, a member indicated by reference numeral 46 in FIG. 3 is a stabilizer attached to the outer periphery of the tip end cylinder 40a of the center excavating bit 40, and is excavated by the bit blade 405 as the excavation progresses. It has a function of contacting the hole wall and maintaining the stability of the central drill bit 40. Further, the member indicated by the reference numeral 48 is a connecting member that rotatably connects the left and right and the center excavating bits 36, 38, 40 on the upper end side, and the upper end cylinder 3 of the left and right excavating bits 36, 38.
Hollow left and right cylindrical bodies 48 fitted around the outer circumferences of 63 and 383
1, 482, a central tubular body 483 fitted to the outer periphery of the upper end tubular body 403 of the central drilling bit 40, and these tubular bodies 48.
It is composed of a pair of connecting plates 484 connecting between 1 to 483.

Since the connecting member 48 penetrates into the excavated groove as the excavation proceeds, the diameters of the cylinders 481 to 483 are smaller than the diameters of the excavating bits 36, 38, 40, and the connecting members 48 are connected to each other. The thickness of the plate 484 is smaller than the thickness of the bit pieces 422 and 442. By the way, in the ground excavating device configured as described above, the excavating bit portion 34 is arranged on the front side of the support column 18, and the cylindrical excavating bits 36, 38, 4 are arranged.
Erected so that 0 is almost vertical to the excavated ground surface,
The percussion head 28 and the rotary drive 30 are started. When the percussion head 28 and rotary drive 30 are started, the cylindrical drill bits 36, 38,
An impact force and a rotational force are simultaneously applied to 40 from the upper end side thereof, whereby the ground is excavated by the bit blades 365, 385, 405, and first, as shown in FIG. 5 (A),
Circular excavation holes a _{1 to} a ₃ corresponding to the shapes of the bits 36, 38, 40 are formed in advance (first step).

Then, such circular drill holes a _{1 to} a _{3 are formed.}
When the formation progresses and the left and right plate-shaped excavation bits 42, 44 reach the ground surface, the percussion head 2 is attached to the left and right plate-shaped excavation bits 42, 44 via the impact force transmission portion A.
In addition to transmitting the impact force of No. 8, the reciprocating movement force is transmitted via the movement direction conversion unit B, so that the left and right plate-shaped excavating bits 42, 44 apply the impact force to the ground while reciprocating. Become.

FIG. 6 shows the details of the operation of the moving direction converting portion B for converting the rotational force applied to the central excavating bit 40 via the rotary drive device 30 into reciprocating movement. Now, for example, in the initial state as shown in FIG. 6A, it is assumed that the cam 408 is aligned with the minor axis direction of the cam surface 426.
If the center excavating bit 40 rotates clockwise, the cam 408 rotates approximately 90 ° from the position shown in (A), and when the cam 408 coincides with the long axis direction of the cam surface 426, the cam surface 426. Since the long axis of the plate is slightly longer than the entire length of the cam 408, the sleeve 40b is formed by the plate-shaped drill bit 42,
Almost no movement occurs in the plate thickness direction of 44.

Then, the center excavating bit 40 further rotates clockwise, and as shown in FIGS. 6A to 6B, the cam 408 is approximately 180 so that it is aligned with the minor axis direction of the cam surface 426. When rotated by a degree, the cam 408 moves the cam surface 426 to the right in FIG. 6 in this process, and this movement causes the central sleeve 423 to move in the same direction.
2 is connected via the substrates 421 and 441,
As a result, the left and right plate-shaped excavating bits 42, 44 move in the same direction by the same amount.

Next, the center excavating bit 40 further rotates clockwise, and as shown in FIGS. 6B to 6A, the cam 408 is approximately 180 degrees so as to coincide with the minor axis direction of the cam surface 426. When rotated, the cam 408 moves the cam surface 426 to the left in FIG. 5 in this process, and the left and right plate-shaped excavating bits 42 and 44 move to the left by the same amount in the same manner as described above. After that, the center excavating bit 40 moves one reciprocation every one rotation, and the moving stroke l is
The length is equivalent to the protruding portion of the cam 408.

In this case, during the rotation process of the cam 408, the left and right excavating bits 36, 38 and 40 are connected to the connecting member 48.
Although it is possible to rotate by the, the movement in the other directions is restricted, so the left and right plate-shaped excavating bits 42, 44 are
Moves only in the direction of the straight line connecting the centers of the drill bits 36, 38, 40, and hardly moves in the thickness direction of the bit pieces 424, 444. When such reciprocating movement is performed, the bit pieces 424 and 444 of the left and right plate-shaped excavating bits 42 and 44 are formed.
Since the ground between the circular excavation holes a _{1 to} a ₃ is excavated at this time, and the impact force is also applied at the same time at this time, for example, it is necessary to form the groove-shaped excavation grooves b _{1 and} b ₂ which are thin even in the ground where gravel is mixed. Can be performed (second step, see FIG. 5B).

In particular, in the excavator having the above-mentioned structure, the length of the bit pieces 424 and 444 is substantially the same as the reciprocating stroke l, and the ridges are arranged so as to be orthogonal to each other. Can be excavated. Then, when the excavation proceeds and the upper ends of the excavation bits 36, 38, 40 approach the excavation ground surface, the excavation is temporarily stopped, and the percussion head 28 and the excavation bits 36, 38, 40 are stopped.
The connection with and is disconnected by the rod breaker 24, and the drill bits 36, 38, 40 are supported only by the load holder 26,
A new rod is added to the upper end, the same operation as described above is performed, the excavation is performed again, and the excavation groove is formed to a desired depth by appropriately repeating such an operation.

When the circular excavation holes a _{1 to} a ₃ and the groove-shaped excavation grooves b _{1 and} b ₂ are formed to a predetermined depth as described above, the rods to which the excavation bits 36, 38 and 40 are added are removed. After being pulled up by the feeding device 32, the first and second steps are sequentially performed by using the circular excavation hole a ₃ located at the end as a guide, and the circular excavation holes a _{4 to} a ₅ and the grooved excavation hole b _{3 are performed. ,} b ₄ are formed. Then, by successively repeating the same steps successively, a drilling hole of a predetermined length is formed in the ground, for example, by replacing the bentonite mud filled in the drilling hole with concrete, the continuous underground wall Is formed.

The circular drilling hole a ₁
According to ...... a _n and the groove-shaped borehole b ₁ ...... b _n and method of the present invention for forming a between the plurality of circular borehole a ₁ ~a _3, than the diameter of the circular drilling a ₁ ~a ₃ Since the groove-shaped drill holes b _{1 and} b ₂ having a small thickness are formed, and at this time, the impact force is applied when the circular and groove-shaped drill holes a _{1 to} a _3, b _{1 and} b ₂ are formed. Even on the ground where gravel is mixed, the gravel can be crushed by this impact force.

According to the construction method of this embodiment, circular excavation is performed.
Hole a₁~ A₃These circular drill holes after preforming
a₁~ A₃In between, reciprocating movement of the plate-shaped drilling bits 42, 44
The ends are circular drill holes a₁~ A₃In succession
And a circular drilling hole a₁~ A ₃Thinner than the diameter of
Ditch hole b_1,b₂The formation of drill holes
Efficiency is also improved.

In the above embodiment, the circular excavation hole a _{1 is} formed by the plate-shaped excavation bits 42, 44 which reciprocate in the same direction.
Although the case where the grooved excavation holes b _{1 and} b ₂ are formed between the a to a ₃ has been illustrated, for example, a plurality of cams of the movement direction conversion portion B are provided, and the left and right plate-shaped excavation bits 42 and 44 have different directions. The grooved excavation holes b _{1 and} b ₂ may be formed by reciprocating.

Further, in the above-mentioned embodiment, the construction method in which three circular drill holes are formed in advance is exemplified.
A plurality of the above can be adopted.

[0036]

As described above in detail in the embodiments,
According to the ground excavation method of the present invention, an excavation hole having a thin thickness can be efficiently excavated.

[Brief description of drawings]

FIG. 1 is a side view of a work vehicle equipped with an excavating bit portion of an excavating device used in a ground excavating method according to the present invention.

FIG. 2 is a front view of FIG.

FIG. 3 is a front view of an excavating bit unit mounted on the work vehicle of FIG. 1.

4 is a cross-sectional view taken along the line AA of FIG.

FIG. 5 is a process explanatory view showing the steps of the excavation method of the present invention in order.

FIG. 6 is an explanatory diagram when forming a trench excavation hole in the process explanatory diagram shown in FIG. 5;

[Explanation of symbols]

a _{1 to} a ₅ circular drill hole b _{1 to} b ₄ grooved drill hole 28 percussion unit (impact application device) 30 rotary drive device 34 drill bit part 36 left drill bit 38 right drill bit 385 bit blade 40 center drill bit 405 bit Blade 408 Cam 42 Left plate-shaped drill bit 426 Cam surface 44 Right plate-shaped drill bit A Impact force transmission part B Moving direction conversion part

Claims (1)

[Claims] 1. A ground excavation method for forming a wall in the ground by forming a groove-shaped excavation hole in the ground and filling the interior of the excavation hole with a curable mud to cure. Firstly formed in advance by rotating a plurality of circular drill holes at predetermined intervals while applying impact to the bit
And a step of forming a groove-shaped drilling hole having a thickness smaller than the diameter of the circular drilled hole between the circular drilled holes to a predetermined depth by reciprocating while moving the plate-shaped drilling bit while applying an impact. And a step of forming the circular drilling hole to a predetermined depth, and then sequentially repeating the first and second steps using the circular drilling hole located at the end as a guide.