JPH02136496A - Method and device for propulsive construction of bulky gravel stratum - Google Patents

Abstract

PURPOSE:To conduct positive operation, in which trouble is hardly generated, at atmospheric pressure by excavating and propelling a facing while muddy water is forward into an excavating chamber and discharging floating stone to the outside of the excavating chamber. CONSTITUTION:A facing 3 is excavated and propelled while high-concentration high specific-gravity muddy water is fed into an excavating chamber 4 formed between a partition wall 2 and the facing 3 in a shielding cylinder 1. Stone 6 being separated from the facing 3 and having a comparatively large diameter is floated into a mixed liquefied body 5 in which muddy water and excavated soil and sand are mixed and agitated. The internal pressure of the liquefied mixed body 5 is kept by blocking an expansible contractible discharge cylinder 7 by an extensible substance fitted to the partition wall 2, and stone 6 is discharged outside the excavating chamber 4 as it is from the discharge cylinder 7. The discharge cylinder 7 is opened and closed instantaneously by air pressure going in and out from an air inlet, and an inner pipe is made of a rubber and the holding of foreign matters such as stone 6 and the blow- off of muddy water from the clearance of a valve are prevented. Accordingly, space scaling up a sludge port can be maintained, thus reducing trouble.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention relates to a coarse gravel bed propulsion method for constructing a tunnel in a sand and gravel bed containing relatively large-diameter stones, and its covering.

"Conventional technology" Relatively large diameter stones called boulder targets (75 to 400
When constructing sewage pipes, etc. in strata that contain a large amount of am), the conventional mud water pressurization propulsion method uses dilute mud water with a relatively low specific gravity, so the goal of cobblestones in the excavated soil is how well it can be stirred inside the excavation room. However, it is difficult to suspend them in the muddy water and they settle to the bottom of the excavation chamber.If excavation continues in this state, there is a risk that the excavation chamber will become clogged and it will be impossible to excavate. Furthermore, even if it were possible to suspend the gravel in muddy water and take it into the shield machine, this construction method uses a pump to circulate the mud, so it would have to be finely crushed by a crusher in the shield machine, or the mud and gravel would have to be separated using a trommel, etc. However, since these devices are very large, it is difficult to apply them to shield machines with relatively small diameters.

On the other hand, in the case of the earth pressure balance type propulsion method, the cutter is a spoke type cutter without a cutter face, and it is easy to take the cobblestone target into the excavation chamber, and the excavation chamber is also filled with mud that is close to the excavation ground. However, since the inside of the excavation chamber is a plastic body or a state close to it, the excavated soil must be forcibly taken in by a machine such as a screw conveyor in order to be taken into the shield machine. In general, screw conveyors with a structure in which an auger is inserted into the casing can only take in stones up to about 1/3 of the diameter of the auger, so if you want to take in a target of 300 mo+, for example, the diameter of the auger itself is 9001m
1 is required, and the shield machine itself has a fairly large external shape.

In addition, when propelling the shield tube, muddy water is injected into the excavation chamber to turn the excavated soil into a plastic slurry, and when relatively large-diameter boulders separated from the face are discharged from the inclined pipe to the outside of the excavation chamber along with the mud, the mud is It was necessary to create a pressurized air chamber inside the shield machine to suppress the formation of debris (Utility Model Publication No. 59-183569). Furthermore, muddy water was injected into the excavated soil to make it liquid, and the boulders that had settled at the bottom of the excavation chamber were tilted. A method of discharging from a pipe has been developed, but it is necessary to create a pressure chamber inside the shield machine (Japanese Patent Application Laid-Open No. 59-210190), and it is difficult to easily propel a coarse gravel layer with atmospheric pressure inside the shield machine. Met.

For the above-mentioned reasons, when constructing a pipe of about 800 to 1000 mm in the ground where there are many cobblestone targets, manual digging has been mainly carried out. However, this construction method also had the drawbacks of being extremely expensive, requiring injection of chemicals over the entire length, and requiring pressurized air, and a poor working environment.

"Problems to be Solved by the Invention" The present invention maintains the inside of the shield machine at atmospheric pressure, easily propels the coarse gravel layer through a relatively small-diameter shield tube, and separates the coarse gravel from the face (approximately 75 mm to 400 mm). The purpose of this project is to construct a mud water pressure propulsion method that can easily take in boulders or targets) into the shield machine.

"Means for Solving the Problems" In order to achieve the above-mentioned object, the present invention provides the above-described method by driving the face to excavate while sending muddy water into the excavation chamber formed between the partition wall provided in the shield cylinder and the face. Relatively large-diameter stones separated from the face are suspended in a stirred mixed liquid body of mud water and excavated soil, and the internal pressure of the liquid body is maintained by blocking an expandable discharge tube made of an elastic material provided on the partition wall. , the coarse gravel layer propulsion method according to the invention, wherein the liquid material is discharged from the discharge tube to the outside of the excavation chamber in accordance with the coarse gravel layer propulsion construction method characterized in that the stones are discharged from the discharge tube to the outside of the excavation chamber. Coarse gravel layer propulsion method according to the above invention in which a thickening agent is contained in the muddy water The coarse gravel layer propulsion method according to the above invention, in which the stones are coarse gravel, and its apparatus are constituted.

"Operation" Therefore, the base end of the shield tube 1 is brought into contact with the tip of the buried pipe 8, the base end of the buried pipe 8 is pushed and propelled with a jack while feeding muddy water into the excavation chamber 4, and the face 3 is excavated with the cutter 9. ,
In the excavation chamber 4, the excavated earth and sand and mud are stirred into a mixed liquid body 5, and the coarse gravel 6, such as the cobbles released from the face 3 and the target, are suspended in the liquid body 5. This flotation causes muddy water to become highly concentrated and has a high specific gravity (
(approximately 1.5 to 1.8), and by adding a thickener to the muddy water, it becomes highly viscous. Furthermore, since it is stirred by the rotation of the cutter arm 10, relatively large diameter stones such as coarse gravel 6 are used. floats in the liquid 5. As the face 3 is excavated and the shield tube 1 is propelled, the internal pressure of the liquid material 5 in the excavation chamber 4 increases, but this internal pressure is prevented by blocking the expandable discharge tube 7 with an elastic material such as rubber provided on the partition wall 2. By opening this, the liquid 5 and the stone 6 are discharged into the shield cylinder 1 outside the excavation chamber 4.

``Example'' This construction method is a mud water pressure propulsion construction method in which mud is injected from the outer periphery of a spoke-type cutter 9 without a cutter face, and is stirred and mixed with excavated soil in the excavation chamber 4 to create a highly concentrated mud with a high soil content. A liquid material 5 with high specific gravity is prepared. A thickener (such as sodium or carboxymethyl cellulose, which dissolves in water and becomes paste-like) is mixed with the muddy water. Although it is a liquid, it has a very high specific gravity and viscosity, and because the inside of the excavation chamber 4 is constantly stirred by the cutter arm IO and arm holder, the large laminar particles 6 remain suspended without settling to the bottom. ing. In this state, a thrust force is applied by the original pusher jack, so that the pressure inside the excavation chamber 4 increases. Therefore, the underground water pressure +0.21'+ which is known as the stabilized liquid construction method.
When the rubber expandable discharge tube 7 (control valve) is opened and closed to maintain the pressure in the excavation chamber 4 at about /aft, the target etc. 6 floating due to the pressure inside the excavation chamber 4 will be shielded with highly concentrated muddy water. discharged inside. Here, discharge tube 7
has the structure shown in the figure, with air inlets and outlets 15', 15
The valve can be opened and closed instantaneously by the air pressure flowing in and out of the valve, and the face is stabilized.The inner cylinder, that is, the discharge cylinder 7, is made of rubber, so even if a foreign object such as a stone 6 is caught in the valve when it is closed, the valve will not close. The muddy water with high concentration mixed with the gravel target taken into the partition wall 2 of the shield tube 1 is separated into the gravel target and muddy water by the screen 13 of the mud storage tank 12. . This screen 1
3 is just a net and does not mechanically vibrate 6 The separated gravel target 6 is discharged by a truck or the like, and the muddy water is discharged outside the mine via a pipe 14 by a vacuum suction device. In this way, no pump or the like is used in the sludge removal line, and the sludge is conveyed only under atmospheric pressure, so if the sludge is smaller in diameter than the sludge removal vibrator 14, it will remove sludge without any problem even if it contains small-diameter cobbles σ, etc. I can do it. Therefore, there is no need for a bulky classifier or crusher such as a trommel.The cobbles are 75 to 300 mm, and the target is stones of 300 mm or more.
The structure is only for injecting and discharging compressed air into the cavity a, so the external shape is very small and there are no mechanically moving parts.The one indicated by 16 in the figure is the discharge pipe. 7 is a reinforcing cloth embedded inside, 17 is a muddy water injection pipe, 18 is a muddy water inlet, 19 is a tail void, and 20 is a prime mover.

21 is a drive gear, 22 is an internal gear, 23 is a seal, and 24 is a swing bearing.

``Effects'' As described above, the present invention does not require any complicated valves or pumps from excavation to sludge removal, so the mechanism is simple, and the process from taking in coarse gravel such as a cobblestone target to sludge removal is reliable and trouble-free. Work can be carried out at atmospheric pressure. In addition, since the present invention has a simple mechanism, space for enlarging the mud removal port can be maintained, and for example, a mud removal port and discharge tube 7 (control valve) with an internal diameter of 300 + a + s can be installed in a shield excavator with a finished internal diameter of 900 am. is possible.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal side view showing the mud water pressurization propulsion method of the present invention;
Figure 2 is a front view of Figure 1 seen from the left, Figure 3 is a side view of the expandable discharge tube, Figure 4 is a side view of the coarse gravel being discharged,
FIG. 5 is a vertical sectional view taken along the line A-A in FIG. 3, and FIG. 6 is an enlarged longitudinal sectional view of the end of the expandable and retractable discharge pipe. 1. Shield tube, 2. Partition wall, 3. Face, 4. Excavation chamber, 5. Stirring mixed liquid, 6. Stone, 7. Expandable discharge tube, 8. Buried pipe, 11・・Shield machine, 15・
・Outer cylinder.

Claims (6)

[Claims] (1) The face is excavated while sending high-concentration, high-density mud into the excavation chamber formed between the partition wall provided in the shield cylinder and the face, and the mud is separated from the face into a stirred mixed liquid body of the mud and excavated soil. A stone with a relatively large diameter is suspended, and the internal pressure of the liquid is maintained by closing an expandable discharge tube made of an elastic material provided on the partition wall, and the stone is delivered in a round form to the outside of the excavation room from the discharge tube. A coarse gravel layer propulsion method characterized by discharge. (2) The coarse gravel bed propulsion method according to claim (1), wherein the liquid material is discharged from the discharge pipe to the outside of the excavation chamber during propulsion. (3) Claim (1) or (2) that muddy water contains a thickener.
) The coarse gravel layer propulsion method described in ). (4) Claim (1), (2) or (3) in which the stone is coarse gravel.
The coarse gravel layer propulsion method described in . (5) A partition wall is provided in the shield cylinder, a rotary cutter is provided in the partition wall, an excavation chamber is provided between the cutter and the partition wall, and the excavation chamber is formed so as to convey high concentration and high specific gravity muddy water, and the shield cylinder is In a shield machine that fills the excavation chamber with the stirring liquid mixture of muddy water and excavated earth and sand by propulsion, an outer cylinder communicating with the outside air is provided on the partition wall, an expandable discharge tube made of an elastic material is provided inside the outer cylinder, and the The outer periphery of both ends of the ejector tube is connected to the inner circumference of the outer tube, and fluid is allowed to enter and exit between the inner surface of the outer tube and the outer surface of the ejector tube, so that the ejector tube can be opened and closed freely, and the outlet of the outer tube is connected to the atmosphere. A coarse gravel layer propulsion device that is open to the public. (6) The coarse gravel layer propulsion device according to claim (5), wherein the shield tube is propelled by a buried pipe connected to the shield tube.