JPH06173586A - Water sealing method of tail seal of shield machine - Google Patents

Abstract

PURPOSE:To enable sandlike water sealing blocks to prevent back-filling agent and mud water from penetrating from a ground during excavation by filling beforehand back-filling agent into a tail seal part on the side of the ground before excavation. CONSTITUTION:Filling material for water sealing such as grease containing fiber is filled circumferentially into a void 10 on the side of cutting face in the quantities equal to or larger than the volume of a space of the void before starting excavation through a feed pipe 8 provided outside a tail ring 7 and a grout hole 9. And before temporarily assembling segments, the filling agent is filled into a wire brush 1 itself. Next, back-filling agent is filled into a void on the side of a ground from the hole 9 in a similar manner. The back-filling agent is turned into sand-like matters again in a short time so that mud enters voids in the sand-like matters to form a dense blocking. Since there is a hard layer formed by the grease and back-filling agent on the rear side, the grease containing fiber filled into the void on the side of the facing improve further the strength and density difference of a water sealing wall.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of stopping water in a tail seal portion of a shield machine. More specifically, the present invention relates to a water-stopping method capable of increasing a reliable water-stopping effect by using a back-filling injection agent and a water-stopping filler together.

[0002]

2. Description of the Related Art Conventionally, when excavating with a shield machine, it has been generally practiced to prevent muddy water from the ground and the backfill injection agent from entering the machine from the ground side brush through the face side brush. A brush seal as shown in FIG. 4 is used.

In the brush seal (wire brush) shown in FIG. 4, a bundle of straight or waved (corrugated) metal wires 21 are sandwiched between inner and outer steel spring plates 22 and 23. The tail ring 24 is provided with one step or two or more steps at regular intervals. The wire brush is attached by welding or the like along the circumferential direction of the tail ring 24.

However, these wire brushes do not have a function of preventing spring water from the ground, mud water used in the excavation method, and backfill injection material from entering into the machine from the face side brush. If these mud water, backfilling agent, etc., flow into the machine, it will be difficult to carry out the work inside the machine and lead to personal injury, or the operation of the machine will be paralyzed, making excavation impossible.

Therefore, in order to prevent the infiltration of the mud water and the backfilling agent, between the brush seals,
Water is stopped by filling a filler material such as grease containing fibers or grease for the purpose of stopping water between the wires that make up the brush seal. Further, as described in Japanese Patent Application Laid-Open No. 2-176096, these functions have a pressure of 5 kg by maintaining the filling material pressure between the brush seals at a pressure capable of counteracting the groundwater pressure (mud pressure or backfilling agent pressure). /
Experiments have shown that leakage can be prevented even under high water pressure of cm ² or more.

However, in reality, the openings due to the assembling accuracy of the segments, misalignment, and the distortion of the back surface of the segment (especially cracks and scratches easily occur in the RC segment).
Exists. In addition, since fillers such as fiber-containing grease have greater viscosity and pipe resistance than liquids such as oil,
It is impossible to smoothly and instantly enter the gap between the brush seals. Therefore, the mud water and the back-filling agent penetrate into the inside of the machine through these gaps.

Further, since the filling material also contains a considerable amount of air bubbles, and these air bubbles are filled between the brush seals in a state where the air bubbles cannot be easily removed, the filling material contains bubbles (air) in the form of a brush. It is filled in the voids (the space between the brush seals). When excavation is performed in this state, when the bubbles escape from the face side brush (for example, when the backfill injection material is injected at the same time as the excavation, the pressure of the backfill injection material is higher than the pressure of the filling material, Is difficult to escape to the ground side and is driven out to the face of the face), and water leakage occurs.

Further, the grease filled in the voids between the brushes receives pressure from the ground side and adheres to the segments and is removed, so that the volume decreases, and water leaks even if it penetrates this gap. In this case, as a matter of course, the grease of the filler is supplied in an amount commensurate with the amount removed, but the above-mentioned drawbacks act in combination to lead to water leakage.

In particular, using an automatic greasing type supply system,
There is a lot of water leakage in the excavation method that employs simultaneous back-injection (injecting back-filling injectant at the same time as excavation). The reason is that a filler such as fiber-containing grease is injected into the voids between the brushes, the fibers are entangled in the wire brush to fill the gaps between the wires, and at the same time the powder contained in the filler is blocked by the fiber layer. In order to stop water by making a water blocking wall like a dense fiber board, in reality it takes a considerable amount of time to make this water blocking wall, and simultaneous backfilling is more than grease pressure. It is injected at a high pressure at the same time as excavation, and since the injection amount is much larger than the space volume, the pressure of the filling material such as grease cannot completely counter this and leads to water leakage. Especially at the time of initial excavation, there is a lot of water leakage because of the reason and the grease layer does not form a dense water blocking wall as described above. In addition to water leakage, the amount of filler used is large, which is uneconomical. However, in general backfill injection, the backfill injection agent is injected after the segments have been assembled into several links, so there is diffusion and escape into the ground, and the effect on the filler such as grease is less than that of simultaneous backfilling. Although it is small, the above-mentioned drawbacks act and lead to water leakage. In addition, under high water pressure, it is often impossible to stop water with grease containing no fiber.

[0010]

As described above, according to the conventional water blocking method, water leakage continues until the water blocking wall or the water blocking film is formed, or the filtered grease base material is removed from the face blade brush inside the machine. There is a problem that it will be leaked to the building and the work on the premises will be dangerous. Also, a large amount of grease is required, which is costly and wastes time for injection.

It is also conceivable that due to the influence of the segment assembly, for example, when the RC segment is assembled in a cracked state, the surface state becomes complicated, so that the water blocking wall alone cannot stop the water.

In view of the above circumstances, it is an object of the present invention to provide a water stopping method capable of sufficiently stopping water in an automatic filling system and simultaneous back-filling, as well as during initial excavation and continuous excavation.

[0013]

A water stopping method according to the present invention is a water stopping method for a tail seal portion, which is a brush seal attached to at least three stages on a tail ring of a shield machine, before starting excavation. It is necessary to fill the gap between the brush seal on the most natural side and the brush seal on the inner side with the backfill filler, and to fill the gap between the remaining brush seal and the brush seal with the water blocking filler. It has a feature.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The water stopping method of the present invention will be described below with reference to the accompanying drawings.

1 to 3 are cross-sectional explanatory views of the water stopping method of the present invention.

FIG. 1 shows a state in which a brush seal consisting of wire brushes 1 attached to a tail ring of an excavator at three steps at regular intervals is in contact with a segment 2 temporarily assembled before excavation. For the wire brush 1,
A bundle 3 of elastic wire material such as steel wire, aramid fiber (for example, Kevlar (registered trademark) manufactured by DuPont), nylon fiber, polyacetal fiber is sandwiched by an inner peripheral side protective plate 4 and an outer peripheral side protective plate 5 to be integrated. A molded product or the like can be used. As the inner peripheral side protection plate 4 and the outer peripheral side protection plate 5, a steel plate or a SUS material having a thickness of about 1 mm can be used. In addition, 6 is a U-shaped steel which is a fixture for attaching the wire brush 1 to the tail ring 7.

First, as shown in FIG. 2, from the supply pipe 8 and the grout hole 9 provided on the outer side of the tail ring 7, the face 10 on the face of the cutting face (the wire brush on the most face and the wire brush on the inner side thereof) (The gap between them)
The same amount as the space volume, or a slightly larger amount of fiber-filled grease or other water-stopping filler is filled so as to rotate evenly around the circumference. In this case, in the embodiment shown in FIGS. 1 to 3, the wire brush has three stages, but in the case of four stages, the filler is similarly filled in the void of the second chamber from the face side.

However, before the segment 2 is temporarily assembled, the wire brush itself is sufficiently filled with a filler such as a grease containing fibers.

Then, as shown in FIG. 3, the tail ring 7 is attached to the ground side void (the space between the wire brush closest to the ground side and the wire brush inside thereof).
The backfill injection material is filled from the supply pipe and the grout hole 9 provided on the outside.

As the back-filling injecting agent, a suspension type (cement, mortar milk type, water glass-clay type), a solution type (water glass-hardening agent type) and the like which are commonly used can be used. . Since the backfilling agent is initially a liquid, it may flow out from the brush seal to the ground side slightly behind at the beginning, but it generally solidifies into a soft sand in 10 seconds, which does not lead to a large trouble due to the outflow. When the amount of outflow is large, it can be dealt with by increasing the curing speed by changing the ratio of the curing agent. Commonly used backfill injection is basically 2
Since it is in liquid form, the reaction rate and hardness can be easily changed.

The hardened backfilling injecting agent has a property of being crushed into a sandy shape when pressed, and is not a solid lump like stone or iron. Therefore, it is possible to sufficiently deal with eccentricity of segments. it can. Therefore, there is no possibility of damaging or breaking the surface of the segment.

However, when the state after curing is hard and uneasy, an organic powder, for example, a fine powder of polyethylene or paraffin wax, or a fine powder of rubber or plastic is mixed in the back-filling injection agent. As a result, elasticity can be provided and hardness can be adjusted, and adverse effects on the segment surface can be eliminated. In addition, a clay component or a water-soluble polymer may be added to increase the viscosity of the backfill injection material.

Regarding the anticorrosion, there is no fear of corrosion because the backfilling agent itself is alkaline.

When the inter-brush voids are filled with the fiber-containing grease and the back-filling injecting agent by such a procedure, it is possible to suppress water leakage which may occur in actual excavation, particularly in the initial stage of excavation. In order to improve the effect, fill the back-filling injectant and then refill the face side voids with a water blocking filler such as grease containing fibers to create a more delicate and hard grease layer. Is preferred. That is, if the grease containing fibers is filled in the vertical pile as in the past (the filling agent is not filled in the past), it is possible to fill the grease containing fibers with a pressure higher than the rigidity resistance of the wire brush. Although it is not possible, after filling the backfilling agent as described above, this backfilling agent acts as a kind of wall, so it is possible to fill grease containing fibers up to a pressure of about 3.0 to 5.0 kg / cm ^2. You can do it.

Originally, the backfill injecting agent is used to fill the space between the ground produced by excavation during the main excavation and the outer peripheral surface of the segment, and is injected from the grout hole or the supply pipe at a pressure higher than the groundwater pressure. . That is, in the conventional technology, the backfill injecting agent in the liquid state and muddy water, which easily intrudes into the ground side void, spring water, etc., are apt to cause water leakage as described above, but in the present invention, the backfilling injecting agent filled in advance is Is hardened in a mixture with grease. Therefore, the back-filling injecting agent that invades here becomes sandy again in a short time, and the mud enters the sandy gap to perform more dense clogging. Also,
Even if water passes through, it will be blocked by the grease containing fibers in the face side voids, so it will not invade the inside of the plane and will escape to the ground, or it will be left behind as it is. More importantly, the fiber-filled grease that fills the voids on the face side has a sand-like hard layer in the back, where the grease and backfilling agent are mixed, so a much denser and harder grease layer than the conventional technology is required. It is made on the circumference, and the fibers are entangled quickly and become dense. For this reason, the strength and the density difference of the water blocking wall far exceed the prior art.

According to JP-A-2-176096, if the filling material pressure is maintained at a pressure that can withstand the groundwater pressure (mudwater pressure or backfilling agent pressure), water can be stopped even at a high water pressure of 5.0 kg / cm ² or more. As mentioned above, in reality, the filling material is filled in the standing piles at normal pressure, so the pressure of the filling material can withstand only the pressure due to the steel property of the wire brush, which is less than 1 kg / cm ^{2 on} average. . That is, during the initial excavation, the filling material pressure is not enough to withstand the groundwater pressure during actual excavation. While trying to maintain the counter pressure gradually while excavating, the above-mentioned various conditions influence and lead to water leakage. However, according to the water stopping method of the present invention, it is a filling material that already retains a pressure capable of counteracting the groundwater pressure during the initial filling performed in the vertical pile.

Further, excess oil, grease and the like that are compressed enter the sandy gap to enhance the water resistance and further form a sticky sandy water stop block having no voids.

[0028]

As described above, according to the water stopping method of the present invention, the backside injection agent is filled in the natural tail seal portion in advance before excavation. For this reason, the sand-like water blocking block mixed with fiber-containing grease, etc., made by the backfilling agent reliably prevents the backfilling agent and mud water from entering from the ground during excavation.

Further, since the water blocking block serves as a resistor, a water-filling filler such as a fiber-filled grease that fills the voids on the face side is used for a water-stopping purpose. It is possible to finish the water stop wall that has been made early and to be strong. This combined action, that is, the ability to maintain a filling material pressure that can counteract the ground pressure at the time of actual excavation at the time of initial filling performed in a vertical pile is an excellent advantage that the prior art does not have. In the conventional technology, it takes time for the grease containing fibers to be gradually pressurized to form a dense grease layer under ground pressure or water pressure, and during that time, water leakage may occur and grease is wasted. However, the present invention is an excellent technique for creating two types of waterproof structures and functions that differ depending on the atmospheric pressure stage in the vertical pile.

It is also economical because a backfilling agent used to fill the space created by excavation can be used in combination. Further, the backfill injection agent has a high work efficiency because it can be injected in a liquid state when it is injected into the ground side void. In addition, the elastic sandy layer formed by the backfill pouring agent forms a finer sandy layer each time it comes into contact with the backfill pouring agent and mud water that intrude from the ground, which makes it more stable as drilling progresses. It is possible to stop water safely.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of a water stopping method of the present invention.

FIG. 2 is an explanatory cross-sectional view of the water stopping method of the present invention.

FIG. 3 is a cross-sectional explanatory view of the water stopping method of the present invention.

FIG. 4 is an explanatory diagram of an example of a wire brush used in the water stopping method of the present invention.

[Explanation of symbols]

 1 wire brush 2 segment 3 tail ring

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sueishi, 18-21 Chayamachi, Kita-ku, Osaka Toyosaki Building Nikko Grease Co., Ltd. Stock company Tsuchiura factory

Claims (3)

[Claims] 1. A method of stopping water in a tail seal part comprising a brush seal attached to at least three stages on a tail ring of a shield machine, wherein the brush seal on the most natural side and the brush seal on the inner side thereof are provided before the start of excavation. The back seal material is filled in the gap between the seal seal and the gap between the remaining brush seals and the brush seal, and the tail seal part of the shield machine is stopped. Water way. 2. The water stopping method according to claim 1, wherein the water stopping filler is a grease containing fibers. 3. The tail seal portion is a brush seal integrally formed by sandwiching a bundle of elastic wire rods between an inner peripheral side protection plate and an outer peripheral side protection plate in the axial direction of the tail ring at regular intervals. The water stopping method according to claim 1 or 2, which is provided.