JP2536736B2 - Shield machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of excavating while controlling the direction of a shield machine for constructing a tunnel in the ground.

[Conventional technology]

A conventional shield excavator, particularly a mechanical shield excavator, includes a rotating part having a large number of cutters planted on the front surface. The rotating part rotates around the propulsion axis and is propelled into the ground by the propulsion jack. The earth and sand excavated by the cutter is turned into mud and discharged from the rotary part of the excavator. Segments are assembled in the space created by the advance of the excavator to form a tunnel.

In addition to the above-mentioned cutter, the rotating portion is provided with an over-cutter or a copy cutter that projects in the outer peripheral direction at the time of curve construction or direction correction. When making a curve or correcting a direction, an overcutter or a copy cutter is projected from a rotating part to disturb surrounding rocks so that the excavator can easily bend along the curve or the correcting direction.

[Problems to be Solved by the Invention]

As described above, in the conventional mechanical shield machine, the over cutter or the copy cutter is used for the curved construction and the direction control of the tunnel. The use of this overcutter or copy cutter has the following drawbacks.

In other words, the overcutter and copy cutter have the effect of disturbing the surrounding ground, but the range of disturbed earth and sand is limited to the range of the cutter, and as a result, the uptake of disturbed earth and sand is insufficient, It remains in the ground. If you try to control the direction in such a state, the remaining earth and sand will be pressed against the ground and the ground reaction force will be restored. This reaction force makes it difficult to correct the direction of the machine.

Furthermore, as another problem, wear of an overcutter, a copy cutter, or the like occurs due to a difference in soil quality or long-distance excavation. Due to this wear, the projecting stroke at the beginning of design is lost, the range of ground disturbance is narrowed during curve construction and direction correction, and the effect of using the cutter is diminished. In addition, depending on the soil quality, the cutter blade may disappear altogether.

On the other hand, JP-A-57-61198 and JP-B-48-905 disclose that the high pressure water is jetted to relax the ground, as in the present invention described later.

However, none of these methods forcedly remove the cutting soil, and as a result, loose soil stayed there and was compacted again with the progress of the excavator or due to earth pressure. It is difficult to proceed. Therefore,
The present inventors have not obtained information that this type of conventional example was successful.

Therefore, an object of the present invention is to solve the above-mentioned drawbacks and to enable desired curve construction and direction correction without being affected by the difference in sediment and soil quality, and even long-distance excavation. With the goal.

[Means for solving the problem]

The above problem is a method of excavating while rotating the rotating part of the shield machine, in which the excavator outer shell within 1 m behind the tip of the rotating part of the front surface,
15 ° ~ 30 ° to the axis forward of the outer periphery of the machine
Within the angle range of °, high-pressure liquid is sprayed at a pressure of 200 kg / cm ² or more and a flow rate of 10 to 60 liters / min only in the direction in which it is about to bend, and the surrounding ground is dug out, and The feature is that the earth and sand excavated in the overdubbing process is continuously discharged from the front surface of the rotating part of the excavator to the inside to control the direction of the shield excavator.

[Action]

Here, water is usually used as the high-pressure liquid to be sprayed, but muddy water can also be used for the ground that is highly disintegrating. The injection angle θ (see FIG. 8) of the high-pressure liquid injection device with respect to the excavation axis of the excavator varies depending on the mounting position of the injection device, but is 15 ° to 30 °, and optimally 20 °. 15 °
If it is less than, the disturbing range of the ground is narrow and it becomes difficult to control the direction.If it exceeds 30 °, the disturbing range is too wide and the overdug becomes excessively large, and the ground collapses and the effects on the ground part. In addition, it adversely affects the assembly of the segments, and the amount of backing material injected becomes unnecessarily large.

The high-pressure liquid is jetted by the nozzle that constitutes the jetting device. A single nozzle or a plurality of nozzles are provided on the outer shell of the shield machine as needed. The injection pressure varies depending on the soil quality, but a pressure of 200 kg / cm ² or more, the preferred range is 200-
It is 300 kg / cm ² . The diameter of the nozzle should be selected according to the degree of curve construction, direction correction and soil quality. Injection pressure is 200k
If it is less than g / cm ² , the excavation capacity is poor, and it is possible to increase the discharge flow rate for the purpose of enhancing only the excavation capacity, but this is not realistic because the amount of sludge is excessively increased.

In excavation, not only injection pressure but discharge flow rate largely controls. The flow rate is 10 to 60 liters / min.
If the flow rate is less than 10 liters / min, excavation capacity is poor and it becomes difficult to remove mud. If it exceeds 60 liters / min, the excavation capacity becomes large, resulting in good sludge discharge.However, if excessively dug excessively, the ground collapses, the above-ground portion is affected, the backfill injection amount increases, and the segment It adversely affects the assembly of.

In order to obtain high-pressure liquid, a high-pressure pump is used for the liquid injection equipment. The sludge is discharged by introducing it from the front of the rotating part of the excavator.

When the ground around the rotating part is cut with the high-pressure liquid sprayed from the nozzle, most of the cut earth and sand is slit from the front of the rotating part of the shield machine as the rotating part rotates and the machine advances. After that, it enters the rotating part and is discharged through the sludge pipe.

As a result, the cut earth and sand do not stay around the shield machine, and the direction of the shield machine can be controlled without receiving the ground reaction force. Moreover, since the injection pressure can be adjusted from inside the machine, the disturbance range can be adjusted according to the curvature of the construction curve and changes in the soil quality.

〔Example〕

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

FIG. 1 is a sectional view showing the outline of the present invention. The front part of the shield machine 1 is a rotating part 2 that rotates around the shaft. A large number of cutter bits 3 are provided on the front surface of the rotating unit 2.
Has been planted. The ground is cut by these cutter bits 3.

The cut earth and sand enter the rotary unit 2 through a front slit (not shown). In the radial direction of the rotating part 2, as shown in FIG.
Is provided. The cutter device 4 has an overcutter or a copy cutter 5 protruding in the outer peripheral direction, and a jack 6 is used to cause the cutter device 4 to protrude from the outer periphery of the rotating portion 2 when necessary. The cutter device 4 is not always necessary in the present invention.

Rotation of the rotating unit 2 is transmitted from a motor 8 installed in a subsequent cylindrical propelling unit 7 via meshing gears 9a and 9b.

A propulsion jack 10 is provided between the propulsion unit 7 and its succeeding member.
Is provided. The propulsion jack 7 propels the propulsion unit 7 together with the rotating unit 2 into the ground ahead.

The inside of the propulsion unit 7 is provided with a mud pipe 11 for supplying mud water for mudizing the earth and sand excavated by the cutter bit 3 and a mud pipe 12 for discharging the mud to the succeeding part. A shielding plate 13 is interposed between the propulsion unit 7 and the rotating unit 2 so that muddy water in the rotating unit 2 does not enter the propulsion unit 7.

The high-pressure liquid injection device 14 according to the present invention is a shield machine 1
The outer contour of the excavator 1, depending on the size of the excavator 1, is installed within 1 m behind the front of the rotating part 2. Injection device
If 14 is installed at a position farther than 1 m, the collapsed earth and sand will stay in front of the rotating part without detouring, and the ground around the front part will not be excavated, and the reaction force of the ground will be received to achieve the intended purpose. It's difficult. Considering the ground conditions, the installation location of the injection device 14,
It can be installed at any position in the circumferential direction where it is expected that there is a need to overdug. In this case, the installation position of the injection device 14 in the tunnel direction is not related to the radius of the shield machine 1 because the reaching distance of the high-pressure liquid is a problem. However, as the radius increases, the number of high-pressure liquid ejecting devices 14 to be installed in the curved direction needs to be increased. When the injection device 14 is provided on the rotating part 2, the injection device 14 and the water pipe are connected by a swivel joint 26 so that the injection device 14 reaches a circumferential position corresponding to the curving direction of the rotating part 2. At that time, the high-pressure liquid is jetted.

The injection device 14 may consist of only the injection nozzle 15, but if a stop valve or an adjustment valve 16 is provided as shown in FIG. 1, the injection pressure and the flow rate can be adjusted individually. In the example shown in FIG. 1, the injection nozzles 15 are installed on one side wall at three locations in the vertical direction, but the number can be increased or decreased depending on the soil quality or curved construction.

Desirable injection angle (mounting angle) θ from the injection nozzle 15
Is 15 to the propulsion shaft of the shield machine 1 as described above.
It is 30 °. FIG. 4 shows an example in which the injection nozzle 15 is attached to the propulsion unit 7 at an angle of 20 ° as an example. The diameter of the injection nozzle 15 is selected within the range of 1.6 to 2.4 mm, but it is also possible to select the diameter of the tip 18 within the above range by interposing a removable nozzle tip 18 inside as shown in FIG. . Changing the tip 18 itself makes it easy to change the nozzle diameter.
The pressure-flow rate relationship at each nozzle diameter is shown in FIGS. 6 and 7. FIG. 6 shows the case where fresh water is used as the liquid, and FIG. 7 shows the case where muddy water is used.

The high-pressure liquid to be injected is supplied from the liquid injection equipment 20 as shown in FIG. The liquid injection equipment 20 in this example is a high pressure pump 21.
And aquarium 22. The high pressure pump 21 is shown in FIG. 6 and FIG.
A pump that delivers a flow rate of 10 to 60 liters / min at a discharge pressure of 200 to 300 kg / cm ² is desirable from the usage range shown in the figure. Fresh water or muddy water is stored in the water tank 22 in consideration of soil quality. The liquid injection facility 20 is mounted on a trolley and travels on a rail 24 laid in a tunnel constituted by segments 23. The high-pressure pump 21 of the liquid injection equipment 20 is an injection device via a high-pressure hose 25.
It is connected to 14.

 Next, the method of controlling the direction will be described.

When controlling the direction of the shield machine 1, the high-pressure pump 21 is activated and about 300 kg / m of fresh water or muddy water in the water tank 22 is operated.
Increase the discharge pressure to cm ² and use the high pressure hose 25 to
Supply to. The adjusting valve 16 is adjusted according to the soil quality of the ground to be cut and the degree of direction control, and the injection pressure and flow rate are adjusted. If it is assumed that the shield machine 1 bends to the right, the shield machine 1 has an angle range of 15 to 20 degrees with fresh water or muddy water from the jet nozzle 15 located on the right wall.
It is sprayed on the ground in front of the outer shell of the above and is cut as shown in FIG. The cut earth and sand are pressed by the water pressure to bypass the front surface of the rotating unit 2 and enter the rotating unit 2 through the slit. The soil that has entered is agitated in the rotating part 2 that is rotating, and the mud pipe is discharged.
It is discharged to the rear from 12.

When the cutter device 4 has the injection device 14, the high-pressure liquid is ejected from the injection device 14 at the time when the injection device 14 coincides with the curving direction. The earth and sand cut by the cutter 5 are diverted to the front surface of the rotating part 2 by the jet flow from the injection device 14, and are transferred to the rear part by the sludge pipe 12 in the rotating part 2.

In this way, a space is created in the curving direction of the shield machine 1 that does not hinder the direction control. Next, shield machine 1
Direction control is performed using the jack 10 for propulsion. The direction control is performed by making the stroke of the left-hand propulsion jack 10 longer than that of the right-hand propulsion jack 10 when leaning rightward.
After bending, the segment 3 is assembled in the space formed in the rear part according to the curvature, and the tunnel is completed.

Hereinafter, the effects of the present invention will be described in detail based on examples.

In the actual shield work, the high-pressure water injection device according to the present invention was equipped, and the reaching distance and cutting state of the injection water were investigated while variously changing the injection pressure, the injection flow rate, and the injection angle.

The construction conditions and soil conditions at this time are as shown in Table 1.

In addition, as shown in FIG.
The position was set to 65 cm from the front of the rotating part (face plate), the injection nozzle diameter was φ = 2.0 mm, and fresh water was used as the injection liquid.

 Table 2 shows the test results under the above conditions.

In Table 2, the jet arrival distance means the distance in the front direction that the high-pressure water jetted from the jetting device effectively reaches, and the distance from the skin plate means the high-pressure water jetted from the jetting device. This is the distance (outside this range is effectively cut) extending outward from the outer wall surface (skin plate) of the excavator that effectively acts (see FIG. 8).

In Table 2, the quality of excavation and sludge is judged to be good. About the jet arrival distance, the case of about 40 cm or more is good so that the earth and sand excavated by high pressure water can be efficiently pushed forward, and the skin plate As for the distance from, if too much excavation is caused, ground collapse, influence on the ground part, increase of backfill injection amount and adverse effect on segment assembly, etc., so about 7.5 cm or more, preferably 7.5 cm ~ The range of 14 cm was considered good. Details of these evaluation criteria are also shown in Table 2. Moreover, since not only the quality of excavation / sludging but also the size of the overdug has an effect, the comprehensive evaluation including the quality of actual sludge is also shown in Table 2.

As is clear from Table 2, the injection angle θ is 15 ° to 30 °
And a pressure of 200 kg / cm ² or more, preferably 200
Good excavation / sludging and over excavation are performed in the range of ~ 300kg / cm ² (in this case, the flow rate under the condition of nozzle diameter 2.0mm is 30.4-37.2 liters / min). It turns out.

On the other hand, in Table 3, another injection nozzle was prepared, and an experiment was performed in which the discharge flow rate and the injection angle were changed. No. 2 in Table 3
Some of the data in the table are also shown. Further, as is clear from Table 1, the above experiment is an experiment for the ground with fine sand and an N value of 40 to 50, but for the consolidated clay silt ground with an N value of about 20, The same experiment as in Table 3 was conducted.

According to these series of results, although the quality of excavation and sludge and the amount of excess digging change depending on the target ground, the injection angle is preferably 15 ° to 30 °, and the discharge pressure is 200 kg / cm ² or more, It is understood from comprehensive consideration that the discharge flow rate is preferably 10 to 60 liters / min.

〔The invention's effect〕

As described above, according to the present invention, a high-pressure liquid is jetted to the outside of the machine obliquely by the jetting device provided in the outer shell of the shield machine, the ground is cut, and the earth and sand are rotated while rotating the rotating portion. Therefore, the sludge pipe provided inside the machine is used to discharge the sludge to the rear.

Therefore, the sand and sand do not remain in the cut space, and the direction control can be easily performed without receiving the ground reaction force in the direction control of the shield machine.

Further, since the injection pressure and the flow rate of the liquid can be adjusted inside the machine, it is possible to form an appropriate space according to the curvature to be constructed or modified and the soil quality.

When the injection device and the cutter device are installed together, the wear and damage of the over cutter and copy cutter are reduced.

[Brief description of drawings]

FIG. 1 shows an example in which the injection device is provided on the side surface of the propulsion unit, FIG. 2 shows an example in which the injection device is provided, FIG. 3 shows an example in which it is provided on the bottom surface of the propulsion unit, and FIG. A cross-sectional view showing a collapsed state of the ground, FIG. 5 is a cross-sectional view of the injection device, FIGS. 6 and 7 are pressure-flow rate diagrams determined by the diameter of the injection nozzle, and FIG. 8 is an evaluation in the present invention. It is an explanatory view of a standard. 1 ... Shield machine, 2 ... Rotating part, 14 ... High-pressure liquid injection device, 20 ... Injection equipment, 25 ... High-pressure hose.

Claims (1)

(57) [Claims] 1. A method of excavating while rotating a rotating part of a shield machine, comprising: an excavator shell within 1 m rearward from a front rotary part tip; 15 ° -30 °
Within the angle range of, the high-pressure liquid is jetted at a pressure of 200 kg / cm ² or more and a flow rate of 10 to 60 liters / min only in the direction of bending, and the surrounding ground is dug out, and A shield excavation method characterized in that the excess excavated soil in the overexcavation process is continuously discharged from the front of the rotating part of the excavator rotating inward to control the direction of the shield excavator.