JPH076354B2 - Muddy water pressure propulsion method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a muddy water pressure propulsion method capable of performing horizontal hole excavation with low propulsion force.

[Conventional technology and its problems]

When constructing a tunnel on the ground, various construction methods are used, and one of them is the stable liquid construction method.

The stable liquid method began in 1914 with oil well drilling, and has been applied to underground continuous wall method, reverse pile method, etc. Came. The basis is, for example, page 3, lines 3 to 6 of the document "Theory and Practice of Underground Continuous Wall Construction Method" (Kiyomitsu Fujii et al., Sankaido, March 1975).
Line "Muddy water, which is a mixture of fresh water and cuttings, fills the well. As the well becomes deeper, this muddy water has the function of suppressing groundwater and gas and safely supporting the fragile strata. It was recognized. ”

In the mud pressure propulsion method, which is based on this stable liquid method, first, a vertical shaft for excavating the excavator and the buried pipe is dug, a plurality of buried pipes are sequentially connected behind the excavator, and the excavation is carried out in the lateral direction. The buried pipe is installed by pushing out the machine and the buried pipe.

In the mud pressure lateral hole excavation method, generally, a face plate type or spoke type cutter is rotated for excavation.
In this case, generally, the shield cylinder equipped with the cutter and the subsequent buried pipe have the same diameter so that the space (tail void portion) from the natural ground is not formed as much as possible. This is because if the tail void part is formed and the tail void part remains unstable, the ground is likely to collapse, the ground is loosened, the pipe is tightened, and the thrust for propelling the buried pipe increases. This is because it causes the inconvenience of having to do so. There is also the problem that the ground above the propulsion unit will sink.

In such a construction method, in order to reduce the thrust,
The lubricant is injected from the inside of the shield cylinder and the inside of the buried pipe toward the outside.

However, with this method, the effect of the lubricant is greatly affected by the soil quality of the natural ground, and is greatly affected by the presence or absence of groundwater, and the certainty is poor. In addition, the injected lubricant is absorbed into the ground, so it is necessary to continuously inject the lubricant during the work, resulting in poor workability and a large amount of lubricant, resulting in poor economy. .

Other methods include those described in JP-A-53-139331 or JP-A-58-101998.
In this method, as shown in FIG. 6, the ground portion is excavated by the cutting portion 71 of the cutter 7 which is rotationally driven by the driving machine 5 via the rotary shaft 6, and the friction provided in front of the shield cylinder 11 is used. The cut 91 forms a tail void portion between the shield cylinder 11 and the propulsion pipe (not shown) and the natural ground. Further, muddy water is injected into the excavation chamber 4 from the muddy water injection port 92 of the partition wall 12 between the excavation chamber 4 and the inside of the shield, and the excavated soil is stirred and mixed with the muddy water in the excavation chamber 4. The agitated mixture in the excavation chamber 4 is discharged or filled under pressure to the tail void portion through a slit or a through hole 93 formed between the friction cut 91 and the shield tube 11 to lubricate them. There is a method to reduce thrust by utilizing the sex.

However, in the above-mentioned conventional method, as shown in FIG. 6, since the muddy water inlet 92 is far from the face, uniform mixing is difficult to be performed. Further, since the muddy water injection port 92 is provided in the middle of the partition wall 12 in the radial direction, the muddy water injected into the excavation chamber 4 passes through the central portion of the excavation chamber 4 and enters the excavation chamber 4. It is discharged from the sludge discharge port 81 provided in the lower part and moves from point to point. For this reason, uniform mixing is not performed in the outer peripheral portion of the excavation chamber 4, and it is difficult to discharge or pressurize the tail void portion from the outer peripheral portion of the excavation chamber 4. Therefore, the tail void portion is left in an unstable state, and the inconveniences such as the subsidence of the ground due to the collapse of the ground and the increase of the thrust due to the tightening of the pipe as described above occur.

As shown in FIG. 7, it is also possible to arrange a mud sending pipe 94 in the hood portion of the shield cylinder 11 and inject mud water from the mud water inlet 95 toward the inside (center part). In this case, compared to FIG. 6, the muddy water inlet 95 is closer to the face, but its position is fixed, so injection is also made from a point and it is difficult to stir and mix, and a liquid material with a high soil particle content is obtained. Absent.

Further, as shown in FIG. 8, it is possible to inject muddy water from the front end portion of the rotary shaft 6 of the cutter 7. in this case,
The muddy water inlet 96 is located at the forefront of the face, but the spread of muddy water is still small, so it is difficult to create a liquid with a high soil particle content near the tail void.

In order to reduce thrust and enable long-distance propulsion, excavated earth and sand are stirred and mixed with muddy water to form a liquid material with a high soil particle content, and this is surely filled in the tail void portion with the ground under pressure. There is a need. If the mixture of muddy water and excavated soil is not a liquid material but a plastic material or a material close to it, it will be difficult to fill the tail void portion. Since the tail void portion is formed on the outer circumference of the shield cylinder 11 and the buried pipe 2, the outer circumference of the face must be a well-mixed liquid material with a high soil particle content. However, in FIGS. 6 to 8 described above, since the muddy water inlets 92, 95, 96 are far from the outer peripheral portion, it is difficult to stir the most important outer peripheral portion. Therefore, a uniform liquid material is not formed, and the tail void portion cannot be reliably filled. This is because the injected muddy water has better fluidity than the excavated earth and sand, and therefore tends to flow to the mud discharge port 81 first, and does not become a sufficiently stirred liquid material at the outer peripheral portion.

The present invention has been devised in order to solve the above problems, and an object thereof is to fill a tail void portion on the outer circumference of a shield cylinder and a buried pipe with a liquid material having a uniform high soil particle content. .

[Means for solving problems]

In order to achieve the above object, the muddy water pressure propelling method of the present invention excavates and propels while injecting muddy water from the outer peripheral portion of the cutter having a diameter larger than the shield cylinder, so that the outer peripheral portion of the face is sufficiently stirred and mixed with the excavated soil. To obtain a liquid with a high soil particle content,
It is characterized in that the tail void portion behind the cutting portion is filled with the liquid in a pressurized state.

〔Example〕

Hereinafter, features of the present invention will be specifically described based on embodiments with reference to the drawings.

FIG. 1 is a schematic sectional view for explaining a mud pressure propelling method according to the present invention.

In FIG. 1, reference numeral 1 designates a tubular machine as a whole, and a plurality of buried pipes 2 are sequentially connected behind the machine 1.
Inside the shaft A for loading the excavator 1 and the buried pipe 2,
A source push jack 3 is provided, and the rear end portion of the buried pipe 2 is pressed toward the excavator 1 by the source push jack 3, whereby the excavator 1 and the buried pipe 2 propel in the formation B.

A partition 12 is provided in the shield cylinder 11 of the excavator 1. In front of the partition wall 12, a rotary shaft 6 which is given a rotational force by a driving machine 5 such as a motor, and a cutter 7 which is connected to the rotary shaft 6 and has an outer diameter larger than that of the excavator 1 are provided. There is. A cutting portion 71 is provided at a predetermined position on the center portion and the outer peripheral portion of the front surface of the cutter 7.

In addition, muddy water injection port at one or more locations on the tip of the cutter 7.
Along with the central axis of the rotary shaft 6, there is a tubular hollow portion 72 from the muddy water inlet 72 to the drive unit 5 side.
61 is perforated, and a mud pipe 62 is connected to the hollow portion 61.
The hollow portion 61 does not necessarily have to be tubular inside the cutter 7, and the hollow portion of the cutter 7 itself may be used.

FIG. 2 is an enlarged view of the muddy water inlet 72 of the cutter 7. The muddy water inlet 72 has an inclined portion 72a that opens outward at the outlet.
Is provided.

A sludge discharge port 81 is formed in the partition wall 12, a sludge discharge pipe 82 and a valve 83 are provided in communication with the sludge discharge port 81, and a sludge storage tank 84 is installed at an end of the valve 83 on the sludge discharge side. .

Further, a stirring rod 63 may be attached to the rotary shaft 6 so that the excavated earth and sand of the face are quickly dissolved in the mud water.

Next, the operation of the excavator used in the propulsion method according to the present invention will be described.

First, mud water is injected from the mud pipe 62 through the hollow portion 61 in the rotary shaft 6 and the mud water injection port 72 toward the outer peripheral direction of the cutter 7, and the excavation chamber 4 formed between the face and the partition wall 12 is formed. Is filled with muddy water and the face of the face is pressurized with muddy water.

Next, the rotating shaft 6 is rotated by the driving machine 5, and the cutter 7 excavates while injecting muddy water from the muddy water inlet 72 in the outer peripheral direction of the cutter 7. If a swivel joint or the like is provided in the middle of the mud pipe 62, the muddy water can be injected even while the rotary shaft 6 is rotating.

As shown by the arrow P in FIG. 2, the sent mud water is supplied to the vicinity of the face of the cutter 7 and the outer peripheral edge thereof, and the excavated earth and sand are easily dissolved in the sent mud water, which is caused by the solid particles of the sent mud water and the excavated earth and sand. The filling effect is promoted, and the face is pressed through the formed mud film to stabilize the face.

At this time, since the outer diameter of the cutter 7 is selected to be larger than the diameter of the shield cylinder 11, a tail void portion C is formed between the outer periphery of the shield cylinder 11 and the buried pipe 2 and the ground after excavation. The tail void portion C is filled with a liquid material having a high soil particle content that is sufficiently agitated and mixed with the excavated soil and sand as it is propelled.

In the present embodiment, while performing the overcut by the cutter 7, the mud water injection port 72 is installed in the outer peripheral portion of the cutter 7, and the mud water and the excavated earth and sand of the ground are agitated and fused, whereby the mud water is sent. A liquid material having a high solid soil particle content, which has a high solidification effect utilizing not only the filling material but also the soil particles contained in the excavated sediment, is formed on the outer peripheral portion of the cutter 7.
The tail void portion C formed by is filled up. This liquid with a high content of solid soil particles has a pressing force to the face, for example, a groundwater pressure of ± 0.2 kg / cm ² and the same pressure, forming a mud film on the ground surface in the same manner as the face, and the pressing force Suppressing the collapse of the ground of the tail void portion C, preventing loose earth pressure,
The thrust is reduced by eliminating the tightening of the ground to the buried pipe.
Therefore, propulsion can be performed with low thrust, which is suitable for the long-distance propulsion method.

After the excavation, the excavated earth and muddy water pass from the sludge discharge port 81 through the sludge discharge pipe 82, and are stored in the mud tank 84 by opening and closing the valve 83 due to the pressure difference between the liquid material at the face and the atmospheric pressure inside the excavator 1. The sludge is discharged, and the slurry is transported by pipes to be transported inside the pipes and discharged outside the mine.

It should be noted that, during the excavation work, the muddy water inlet 72 may be clogged with gravel or the like, but in the present embodiment, the outlet of the muddy water inlet 72 is provided with the inclined portion 72a that opens outward, and thus the hollow portion. 61
By applying a high pressure as indicated by arrow Q, it is possible to blow off and remove the gravel and the like clogged in the ejection port.

FIG. 3 shows another embodiment according to the present invention, and FIG. 4 shows an enlarged view of the same.

In the cutter 7 shown in the figure, the muddy water injection port 73 is provided obliquely forward so that muddy water can be injected in the cutting face direction from between the cutting portions 71 of the cutter 7 as shown in FIG. There is. In this case, in the face part, the excavated earth and sand are more easily dissolved in the mud water, and the effect of clogging the face is increased. In this case as well, the inclined portion 73a for preventing clogging is provided as in FIG.

〔The invention's effect〕

As described above, according to the present invention, by injecting muddy water from the outer peripheral portion of the cutter, a sufficiently agitated liquid material having a high soil particle content can be obtained on the outer periphery of the face. When the tail void portion is pressurized and filled with this uniform liquid material, the ground is self-supporting, and the shield cylinder and the buried pipe are not tightened due to the looseness of the ground. Therefore, the thrust is reduced,
The long-distance propulsion method can be easily performed.

[Brief description of drawings]

FIG. 1 is a schematic sectional view for explaining a propulsion method according to the present invention, FIG. 2 is an enlarged sectional view of a main part of a cutter, FIG. 3 is a sectional view of a cutter according to another embodiment, and FIG. 4 is the same. Enlarged view of essential parts,
FIG. 5 is a front view of the same, and FIGS. 6 to 8 are schematic sectional views for explaining a conventional propulsion method. 1: excavator, 2: buried pipe 3: original push jack, 4: excavation chamber 5: drive machine, 6: rotating shaft 7: cutter, 11: shield cylinder 12: partition wall, 62: mud pipe 72: muddy water inlet , C: Tail void part

Claims (1)

[Claims] 1. A liquid material having a high soil particle content that is sufficiently agitated and mixed with the excavated earth and sand in the outer peripheral portion of the face by excavating and propelling muddy water from the outer peripheral portion of the cutter having a diameter larger than that of the shield cylinder. A muddy water pressure propulsion method characterized in that a tail void portion behind a cutting portion is filled with a liquid in a pressurized state.