JP5763740B2 - How to start the excavator - Google Patents

Description

  The present invention relates to a start method in which a excavator is started from a start shaft having a relatively small diameter in a semi-shield method.

  Conventionally, when starting an excavator from a small shaft (at the initial excavation), a pushing angle (strut) as a spacer member is inserted between the excavator and the propulsion jack or between the propulsion jack and the reaction wall. On the other hand, a starting method is known in which the excavator is sequentially propelled by extending the propulsion jack one stroke at a time and penetrates into the natural ground (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2003-64982

In a conventional method for starting an excavator from a small shaft, it is necessary to allow a steel pipe to penetrate into a natural ground in advance and to secure a space for accommodating the front portion of the excavator in the steel pipe due to the structure and characteristics of the excavator. In this case, after propelling the steel pipe propulsion pedestal and hydraulic jack and propelling the steel pipe, the excavator starts to start after being replaced with the propulsion cradle for excavator propulsion and the hydraulic jack. Extra work processes such as replacement of hydraulic jacks and steel pipe propulsion were required.
In addition, at the stage of installing the excavator, the wellhead has already been mirror-cut and the natural ground is exposed, so there was a risk of earth and sand eruption in the highly collapsible natural ground.

  Furthermore, the hydraulic jack requires a length in the front-rear direction that is longer than the operating stroke. As a result, the space where the excavator can be installed in the starting pit has become narrower, reducing the workability when installing the excavator. Moreover, depending on the size of the starting shaft, the excavator may have to be divided into several parts and put in, and in that case, it took a lot of time for the division work and the reconnection work.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a method for starting an excavator that reduces the work process during initial excavation of the excavator and improves work safety. It is in.

The present invention is a starting method for starting an excavator from a starting shaft in the semi-shield method, which is a bag body that becomes a mat shape when retracted, and extends in the axial direction when compressed air is supplied into the bag. One air jack is used, and the following first to third steps are included.
In the first step, a propulsion base is laid on the bottom of the start shaft, a reaction wall is installed on the inner wall on the opposite side of the start shaft, so that the front faces the direction and the rear surface abuts the reaction wall. Install an air jack.
In the second step, the excavator is installed on the propulsion gantry, and the peripheral portion of the front surface of the air jack is opposed to the annular wheel provided at the rear end of the excavator with the air jack retracted.
In the third step, the air jack is extended and the excavator is propelled through the wheel.

In the present invention, by using an air jack, it is possible to omit work steps such as replacement of the propulsion base and the main push jack, and steel pipe propulsion.
In addition, since it is possible to start immediately after installing the excavator, it is possible to minimize the state in which the natural ground is exposed, and to avoid the occurrence of earth and sand eruption in the highly collapsible natural ground Can do. Therefore, work safety can be improved.

  Further, since the air jack becomes a mat shape when retracted, the length in the front-rear direction can be significantly reduced as compared with the hydraulic jack. Accordingly, it is possible to secure a wide space for installing the excavator in the start shaft, and to improve the workability when installing the excavator. In particular, when the division at the time of turning on the excavator, which was necessary when using a hydraulic jack, becomes unnecessary, the division work and the reconnection work can be eliminated, and the work time can be greatly shortened.

It is a side view of the 1st process of the starting method of the excavator by one Embodiment of this invention. It is an II direction arrow line view of FIG. It is the III-III sectional view taken on the line of FIG. It is a side view including the wheel at the time of (a) retraction and (b) extension of an air jack used for a starting method of an excavator according to an embodiment of the present invention. It is a V direction arrow directional view of FIG.4 (b). It is a side view of the 2nd process same as the above. It is a VII direction arrow line view of FIG. It is the VIII-VIII sectional view taken on the line of FIG. It is a side view of the 3rd process same as the above. It is a side view of the 1st process of the starting method of the excavator by a prior art. It is a side view of the 2nd process of the starting method of the excavator by a prior art. It is a XII direction arrow directional view of FIG. It is the XIII-XIII sectional view taken on the line of FIG. It is a side view of the 3rd process of the starting method of the excavator by a prior art. It is a side view of the 4th process of the starting method of the excavator by a prior art. It is a side view of the 5th process of the starting method of the excavator by a prior art. It is a XVII direction arrow directional view of FIG. It is the XVIII-XVIII sectional view taken on the line of FIG.

Hereinafter, a method for starting an excavator according to an embodiment of the present invention will be described with reference to the drawings while comparing with a conventional technique.
This method is used in an initial excavation stage in which excavation from the start shaft is started in a semi-shielded construction method in which a horizontal shaft is constructed in the ground by a propulsion pipe following the excavator from the start shaft to the arrival shaft. In particular, this method is effective when the inner diameter of the starting shaft is relatively small with respect to the entire length of the excavator, for example, when a propulsion pipe having a nominal diameter of 800 mm is constructed from the starting shaft having an inner diameter of 2500 mm.

(Conventional technology)
Prior to the description of the embodiments of the present invention, a method for starting an excavator according to the prior art will be described with reference to the process diagrams of FIGS. Each process drawing is schematic and does not necessarily show an accurate projection view or cross-sectional view. Each step will be described mainly using a side view (a section of the excavator is a cross-sectional view) viewed from the side in the excavation direction. Moreover, about the 2nd process and the 5th process, the top view (FIGS. 12, 17) and sectional drawing (FIGS. 13, 18) from the shaft back were added. The plan view and the rear view cross-sectional view of other processes are omitted because they can be easily analogized.
Here, the divisions of the first to fifth steps are divisions for convenience in referring to the drawings, and do not necessarily correspond to actual work units.

10 to 18, the vertical axis of the start shaft 9 is denoted by z, the inner wall is denoted by 91, and the bottom is denoted by 92. In addition, an axis in the excavation direction orthogonal to the z axis is denoted by x, and an axis in the left-right direction in the front view of the excavator is denoted by y.
10, 11, 14, 15, 16 which are side views of the respective steps, and FIGS. 12 and 17 which are plan views, the hatched portion indicates a natural mountain, and the left side of the drawing is the digging direction. Hereinafter, the digging direction is referred to as the front, and the side opposite to the digging direction is referred to as the rear. A reaction force wall 85 is installed on the inner wall 91 of the start shaft 9 at the rear, that is, on the right side of the drawing. A foundation frame 80 is laid on the bottom 92 of the start shaft 9. A steel pipe propulsion stand 81 is placed on the foundation stand 80 in FIGS. 10 to 13, and a raised steel member 82 and an excavator propulsion stand 83 are placed in FIGS. 14 to 18.

(Prior art—first and second steps)
As shown in FIGS. 10 to 13, in the prior art, before introducing the excavator 1 into the start shaft 9, a steel pipe 71 for securing a space for accommodating the front portion of the excavator 1 is provided in advance as a steel pipe propulsion wellhead 94. The process of penetrating into is carried out.
After the steel pipe propulsion wellhead 94 is provided on the inner wall 91 of the starting shaft 9, the hydraulic jack 60 is attached to the reaction wall 85 on the steel pipe propulsion base 81 in the first step shown in FIG. Install. Further, an abutment wheel 72 is installed between the piston front end 63 of the hydraulic jack 60 and the rear end of the steel pipe 71.

  Subsequently, in the second step (refer to FIGS. 11 to 13 for the sign), the piston 62 is advanced from the main body 61 of the hydraulic jack 60, and the steel pipe 71 is moved one stroke through the wheel 72 while receiving the reaction force from the reaction force wall 85. Promote minutes. Then, the piston 62 is moved backward, and a push angle 73 is inserted between the wheel 72 and the piston front end 63 to move the piston 62 forward again. This operation is repeated, and as shown in FIGS. 11 and 12, the steel pipe 71 is penetrated deeply into the ground every time the number of push angles 73 is increased.

(Prior art-3rd and 4th steps)
After the steel pipe 71 has penetrated to a predetermined depth, the hydraulic jack 60 for steel pipe propulsion is withdrawn in a third step shown in FIG. Further, in order to adjust the height at which the excavator 1 is installed, the raised steel material 82 and the raised steel material 84 are placed on the bottom of the steel pipe 71 and the excavator propulsion frame 83 is laid. . Further, a natural ground is exposed at the front end of the steel pipe 71, and a wellhead 74 for the excavator 1 is provided.
Subsequently, in the fourth step shown in FIG. 15, the hydraulic jack 65 for propelling the excavator is installed on the propulsion rack 83 for the excavator with the rear surface in contact with the reaction force wall 85.

(Prior art-5th process)
As shown in FIGS. 16 to 18, the excavator 1 is installed on the excavator propulsion rack 83 in the fifth step. At this time, the excavator 1 is suspended from the crane with the front portion inclined downward, and the rear portion is gradually lowered while the front portion is housed in the steel pipe 71 and installed horizontally. With the excavator 1 installed on the propulsion frame 83, the front end 68 of the hydraulic jack 65 faces the wheel 25 attached to the rear end of the excavator 1. From this state, the excavator 1 is pushed by the hydraulic jack 65 through the wheel 25 to cause initial excavation.
Further, in a sixth process (not shown) for propelling the excavator 1 following the fifth process, the hydraulic jack 65 is advanced by inserting a pushing angle between the wheel 25 and the hydraulic jack 65.

Here, the schematic structure of the excavator 1 will be described. Note that FIG. 16 is originally a cross-sectional view in a side view and FIG. 17 is a cross-sectional view in a plan view, but the same figure is shared for convenience. Moreover, in FIG. 17, the code | symbol of each part in the excavation machine 1 is abbreviate | omitted.
The excavation drive part provided in the front part of the excavator 1 includes a non-rotating fixed part and a rotating part. The fixed portion includes a hood 11, an inner cone 14, a partition wall 15 and the like. The rotating unit includes a cutter head 12, an outer cone 13, and the like, and is rotationally driven by a cutter motor 16.

Regarding the fixed portion, the cylindrical hood 11 covers the outer periphery of the outer cone 13. The partition 15 partitions the front shield space and the rear control space. An inner cone 14 is fixed in front of the center of the partition wall 15 and a cutter motor 16 is fixed in the rear. The partition wall 15 is provided with a soil pressure gauge 17. A sludge pipe 18 is connected to the rear of the partition wall 15 at a position where it does not interfere with the cutter motor 16.
The output of the cutter motor 16 is decelerated via the pinion and the gear and transmitted to the outer cone 13.
The inner cone 14 includes a cylindrical portion that pivotally supports the center portion of the cutter head 12 and a tapered portion that has a diameter that increases from the cylindrical portion toward the rear.

Next, the cutter head 12 as a rotating part is fixed to the front end of the outer cone 13 and rotates together with the outer cone 13.
The cutter head 12 excavates mud and crushes gravel using a plurality of types of cutter bits provided on the front surface. The excavated material flows into a shield space defined by the inner wall of the outer cone 13, the outer wall of the inner cone 14, and the partition wall 15.

  The outer cone 13 is disposed inside the hood 11, and a mortar portion that is gradually thickened from the front end side toward the rear end side is formed on the inner wall. The rotation center of the mortar part is provided so as to be eccentric with respect to the axis of the tapered part of the inner cone 14. Further, the mud is scraped up by a scraping plate formed in the mortar portion, and the gravel is guided between the outer cone 13 and the inner cone 14.

The work to be excavated sent to the shield space is crushed by earth pressure. Furthermore, hard gravel or the like that is not crushed by earth pressure is crushed by being compressed between the mortar portion of the outer cone 13 and the tapered portion of the inner cone 14 by the rotational force of the outer cone 13. And it introduce | transduces into the mud pipe 18 connected to the partition 15 with earth pressure.
A cutter motor 16, a mud drain pipe 18, and the like are accommodated in the pipe of the control pipe 19 connected to the rear of the hood 11.
In the semi-shield method, a horizontal shaft is constructed from the start shaft 9 toward a reach shaft (not shown) by the excavator 1 having such a schematic configuration.

As described above, in the starting method of the excavator 1 according to the prior art, the propulsion base 81 for propelling the steel pipe and the hydraulic jack 60 are installed to propel the steel pipe 71, and then the propulsion base 83 for the excavator and the hydraulic jack 65 are used. The excavator 1 starts to be started after being replaced with a new one, and work steps such as replacement of the propulsion frame and hydraulic jack and steel pipe propulsion are necessary.
Further, at the stage of installing the excavator 1, the wellhead has already been mirror-cut and the natural ground is exposed, so there was a risk of earth and sand eruption in the highly collapsible natural ground.

  Further, the hydraulic jack 65 needs to have a length in the front-rear direction equal to or longer than the operating stroke. Accordingly, the space where the excavator 1 can be installed in the start shaft 9 is reduced, and the workability when installing the excavator is reduced. Moreover, depending on the size of the start shaft 9, there are cases where the excavator 1 has to be divided into several parts and put in, and in that case, it takes a lot of time for the division work and the reconnection work. .

(One embodiment of the present invention)
Next, a method for starting an excavator according to an embodiment of the present invention devised to solve the problems of the prior art will be described with reference to FIGS. The annotations relating to each process diagram of the present embodiment are based on each process diagram of the prior art. Moreover, in the figure of this embodiment, the same code | symbol is attached | subjected to the structure substantially the same as a prior art, and description is abbreviate | omitted.

(First step)
As shown in FIGS. 1 to 3, in this embodiment, the propulsion frame 83 for the excavator is laid on the foundation frame 80 after placing the raised steel material 82 on the foundation frame 80. Then, on the propulsion base 83, the rear surface 51 is brought into contact with the reaction force wall 85, and the “air jack 5” which is a characteristic configuration of the present embodiment is installed. Further, a start pit 93 is formed in the inner wall 91 of the start pit 9 in the digging direction.
The first step of this embodiment corresponds to the fourth step of the prior art (see FIG. 15) in the sense that preparation for installing the excavator 1 on the propulsion frame 83 is completed.

The configuration of the air jack 5 will be described with reference to FIGS.
The air jack 5 is a so-called “mat-type air jack”, and is, for example, a rubber bag that becomes a mat shape when retracted, as shown in FIG. An air hose 57 is connected to the air jack 5 from an air source 55 such as a compressor. When the air jack 5 is not used, the air valve 56 is closed. When the air jack 5 is retracted, the thickness from the rear surface 51 to the front surface 53 is relatively thin, for example, about 30 mm.

  On the other hand, when the air valve 56 is opened, as shown in FIG. 4B, compressed air is supplied from the air source 55 into the bag of the air jack 5 and extends in the axial direction to, for example, several hundred mm. Although FIG. 4B illustrates an example in which the stretchable portion 52 swells in a three-stage taper shape, the number of steps and the shape of the bulge are not limited to this, and any specification may be used.

FIG. 4B and FIG. 5 show a state in which the extended air jack 5 is in contact with the annular wheel 2. The cylindrical portion 22 of the wheel 2 is fitted to the inner diameter of the propulsion pipe 19 of the excavator 1, and the flange portion 21 of the wheel 2 abuts against the rear end surface of the propulsion pipe 19.
5 corresponds to the contact area S between the front surface 53 of the air jack 5 and the wheel 2. The air jack 5 presses the wheel 2 with a force obtained by multiplying the compressed air pressure by the contact area S. The pressing force increases as the diameter of the central hole 23 of the wheel 2 decreases, and a pressing force equivalent to that of the hydraulic jack 65 can be obtained depending on the setting of the contact area S. Further, by using the wheel 2, the force of the air jack 5 can be uniformly transmitted to the excavator 1.

(Second step)
6-8, the 2nd process of this embodiment respond | corresponds to the 5th process (refer FIGS. 16-18) of a prior art, the excavation machine 1 is installed on the propulsion mount frame 83, and air jack In this step, the front surface 53 is opposed to the wheel 2 provided at the rear end of the excavator 1.
Here, when FIG. 6 of this embodiment is compared with FIG. 16 of the prior art, the thickness of the air jack 5 at the time of degeneration is smaller in this embodiment than in the prior art using the hydraulic jack 65. There is enough space ahead.

  For this reason, in the prior art, the rear part of the excavator 1 suspended by a crane has to be carefully lowered while tilting the front part downward so as not to hit the hydraulic jack 65. The excavator 1 can be lowered in the state of Therefore, the installation workability of the excavator 1 is improved.

(Third step)
The third step of the present embodiment shown in FIG. 9 corresponds to a sixth step not shown in the prior art.
When the air valve 56 is opened from the second step and compressed air is supplied from the air source 55 into the bag of the air jack 5, the expansion / contraction part 52 of the air jack 5 extends and presses the wheel 2. as a result,
The anchor 21 of the wheel 2 abuts against the rear end surface of the propelling pipe 19 to propel the excavator 1, so that the excavator 1 is inserted into the ground behind the start pit 93. The operator can closely observe the situation when the excavator 1 penetrates into the natural ground, and can respond quickly if an abnormality occurs. Thereafter, a horizontal shaft to the final shaft is constructed by a “main excavation process” in which the ground mud is excavated by the cutter head 12 of the excavator 1.
In addition, the air jack 5 after use can make compressed air in a bag open | release to air | atmosphere, can degenerate, and can return to the original mat shape.

As described above, in the starting method of the excavator 1 according to the present embodiment, by using the air jack 5, the replacement of the propulsion gantry and the hydraulic jack corresponding to the first to third steps of the above description of the conventional technology, In addition, work steps such as steel pipe propulsion can be omitted.
In addition, since it is possible to start immediately after installing the excavator 1, it is possible to minimize the state where the natural ground is exposed (the state after so-called mirror cutting), and in a highly collapsible natural ground Eruption of earth and sand can be avoided. Therefore, work safety can be improved.

  Further, since the air jack 5 becomes mat-like when retracted, the length in the front-rear direction can be significantly reduced as compared with the hydraulic jack 65. Accordingly, a wide space for installing the excavator 1 in the start shaft 9 can be secured, and workability at the time of installing the excavator can be improved.

In addition, in description of said prior art, when throwing the excavator 1 into the starting vertical shaft 9, it does not touch on dividing the excavator 1. However, depending on the size of the starting shaft 9, there are cases where the excavator 1 has to be divided into several parts and put in, and in that case, it takes a lot of time for the division work and the reconnection work. .
On the other hand, in this embodiment, since the installation space can be secured widely, there is a high possibility that the excavator 1 can be installed in an undivided state. In that case, the division work and the reconnection work can be abolished, and the work time can be greatly shortened.

  As mentioned above, this invention is not limited to such embodiment, In the range which does not deviate from the meaning of invention, it can implement with a various form.

1 ... excavator,
2 ... this wheel,
5: Air jack 51: Rear surface 53: Front surface
83 ... (for excavator) propulsion stand,
85 ... reaction wall,
9 ... Starting shaft, 91 ... Inner wall, 92 ... Bottom.

Claims (2)

In the semi-shield method, a starting method for starting the excavator (1) from the starting shaft (9),
Using a single air jack (5) that is a bag that is matted when retracted and that extends in the axial direction when compressed air is supplied into the bag,
A propulsion frame (83) is laid on the bottom (92) of the start shaft, a reaction wall (85) is installed on the inner wall (91) opposite to the start direction of the start shaft, and the front surface (53) is the direction of travel A first step of installing the air jack so that the rear surface (51) faces the reaction force wall;
The excavator is installed on the propulsion gantry, and with the air jack retracted, the peripheral edge of the front surface of the air jack is opposed to an annular wheel (2) provided at the rear end of the excavator. Two steps,
A third step of extending the air jack and propelling the excavator through the wheel;
The starting method of the excavator characterized by including.   The method of starting an excavator according to claim 1, wherein in the second step, the excavator can be installed on the propulsion base in an undivided state.

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