JPH0674714B2 - Tunnel construction method - Google Patents

Description

The present invention relates to a method of constructing a mountain tunnel and various tunnels such as a shield pit for laying water and sewer pipes or various cables, more specifically, a tunnel. The present invention relates to a mortar pressure-feeding method for filling the inside and outside of a lining material provided inside.

[Conventional technology]

Conventionally, for example, when constructing a shield mine for laying a water supply pipe or the like, while supporting a circular hole already excavated in the ground with a cylindrical shield frame, by a cutter rotatably provided at the front end of the shield frame, The above circular holes are sequentially dug.

Then, on the inner surface of the circular hole at the rear of the shield frame, for example, a lining material divided into arcs called segments is installed so that the mortar can be backfilled between the outer surface of the segment and the inner surface of the circular hole. ing. This backfilling is carried out for the purpose of suppressing loosening of the ground, prevention of subsidence of the ground surface, prevention of water leakage into the shield pit, and prevention of concentrated load action on the segments.

Further, after laying a water pipe or the like in the completed shield pit, usually, mortar is filled between the inner surface of the segment and the water pipe.

By the way, in the shield mine, due to circumstances such as the equipment for operating the shield machine, the equipment for carrying out sediment and the equipment for carrying in the segments, etc., the above mortar is usually
It is pumped from the ground by a pump, mixed with a separately supplied coagulant, and then backfilled or infilled. At that time, in order to reduce the specific gravity of the mortar and facilitate the pressure feeding, it is known to add a foaming agent to the mortar, stir while blowing air, foam, and then pressure feed.
The discharge pressure of the pressure feed pump is about 16 kg / cm ² , and the diameter of the pipe for pressure feed is about 2 inches. The specific gravity of the mortar before mixing with air is about 1.8, and the specific gravity of the mortar after mixing with 50% of air is about 0.82.

[Problems to be Solved by the Invention]

However, as described above, even if a foaming agent is added to the mortar before pumping, and air is fed in and stirred to foam, the bubbles in the mortar are crushed by the pressure for pumping, or the pumping distance is increased. Often extends over a long distance of about 2 km or more, so there is a problem that many bubbles dissipate during pumping. In this way, when air bubbles in the mortar are lost, the fluidity of the mortar decreases, and the mortar gradually settles over time,
Since solidification starts, it becomes difficult to carry out pressure feeding over a long distance, and the substantial consumption of mortar increases, resulting in an increase in cost.

In addition, when constructing a mountain tunnel, when the mortar is backfilled between the lining material and the ground, the same problem as described above occurs.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, the tunnel construction method described in claim 1 in the scope of the claims of the present specification, in order to solve the above-mentioned problems, pressure-feeds the mortar through the already-finished portion of the tunnel and removes the pressure-fed mortar. In the tunnel construction method of backfilling the inside of the lining material or filling the inside of the lining material, the synthetic resin particles are mixed into the mortar prior to pressure feeding, and at the time of mixing, the mortar is injected from the top of the mixer. On the other hand, the expanded synthetic resin particles are characterized by being injected from below.

Moreover, the construction method of the tunnel described in claim 2 is
In the method of constructing a tunnel in which mortar is pumped through the already-finished portion of the tunnel, and the pumped mortar is backfilled inside or lining inside the lining material, the mortar contains expanded synthetic resin particles prior to pumping. It is characterized in that a cement film is adhered and formed on the surface of the expanded synthetic resin particles in advance when mixed.

[Action]

According to the tunnel construction method of the above-mentioned claim 1, the foamed synthetic resin particles are mixed into the mortar for back-filling or inside-filling that is pumped into the tunnel. While the expanded synthetic resin particles are injected from below. That is, since the expanded synthetic resin particles have a smaller specific gravity than the mortar, the expanded synthetic resin particles can be mixed uniformly by mixing the expanded synthetic resin particles from below the mortar.

Further, during pressure feeding, the expanded synthetic resin particles do not dissipate into the atmosphere due to the pressure for pressure feeding or disappear from the mortar during long-distance pressure feeding, so the volume of the mortar decreases and the specific gravity decreases. Does not increase. further,
By uniformly mixing the foamed synthetic resin particles with the mortar, it is possible to prevent the deterioration of the fluidity of the non-uniform part that has occurred in the past, so that it is possible to secure sufficient mortar pumping capacity and reduce the consumption of mortar. You will be able to suppress.

Further, in the method of constructing a tunnel according to claim 2, foamed synthetic resin particles are mixed in the mortar in the same manner. However, in general, the mortar and foamed resin particles have not only a difference in specific gravity but also mixing. The affinity when doing is not good.

Therefore, when mixing, by forming a cement film on the surface of the expanded synthetic resin particles in advance, the affinity between the expanded synthetic resin particles and the mortar is increased, and the difference in specific gravity between the expanded synthetic resin particles and the mortar is increased. Since the amount is reduced, uniform mixing can be easily performed.

Therefore, it is possible to ensure a sufficient mortar pumping capacity and to suppress the consumption of mortar.

[Embodiment 1] An embodiment relating to a tunnel construction method relating to claims 1 and 2 in the claims section of the present specification will be described with reference to Figs. 1 to 3. , As follows.

As shown in FIG. 2, a shield machine 1 in a construction device for a shield pit 3 as an example of a tunnel includes a rotary excavator 4 equipped with an appropriate cutting blade for excavating the shield pit 3 in a natural ground 2. It is equipped at the tip. Behind the rotary excavation unit 4, a cylindrical shield frame 5 for supporting the excavated shield pit 3 is arranged. At the rear end portion of the shield frame 5, a tail seal 5a inclined rearward inward is provided. Ground 2 to shield frame 5
The load applied to the shield is received by the plurality of shield jacks 40.

A cylindrical casing 41 is arranged in the shield frame 5, and a screw conveyor 42 for carrying out the earth and sand excavated by the rotary excavator 4 is rotatably accommodated in the casing 41. A rotary discharger 43 is arranged at the unloading side end of the screw conveyor 42, and the earth and sand discharged by the rotary discharger 43 are loaded on an appropriate unloading vehicle or the like via the conveyor 44 and carried out of the shield pit 3. It has become so.

As shown in FIG. 1, inside the shield pit 3 behind the shield frame 5, the shield pit 3 is formed into an arc shape as the shield digging proceeds, and a predetermined number of them are arranged in the circumferential direction. .. as the lining material constituting the ring body are sequentially arranged by connecting adjacent ones with a non-bolt or the like. Each segment 6 has a hole for supplying a resin-filled mortar 7 to be described later into the space between the segment 6 and the shield pit 3.
6a is open.

The shield pit 3 communicates with the ground via a vertical shaft 8. On the ground, a mortar pumping section 9 for pumping the resin-filled mortar 7 mixed with the foamed synthetic resin particles to a working position in the shield pit 3, and a resin-filling mortar 7 for setting the resin-filling mortar 7 to the working position. Coagulant supply unit 10 for supplying a coagulant
And are provided.

The mortar pumping section 9 includes a cement silo 11 containing cement and a clay sand silo 12 containing clay sand.
It has and. The cement and clay sand in each of the silos 11 and 12 are metered by metering devices 13 and 14 so as to have a predetermined mixing ratio, and are sent to the mortar mixer 15.

Water is further supplied to the mortar mixer 15 from a raw water tank 16 by a water supply pump 17, and these cement, clay sand and water are kneaded in the mortar mixer 15 to form mortar.

Subsequently, the mortar in the mortar mixer 15 is sent to the mixer 18 and injected into the mixer 18 from above. On the other hand, the expanded synthetic resin particles are stored in the tank 20, and the expanded synthetic resin particles are supplied to the mixer 18 from the bottom.

A mixing means such as a screw conveyor is arranged in the mixer 18, and the mortar and the expanded synthetic resin particles are mixed by this mixing means to form the resin-containing mortar 7. In that case, since the expanded synthetic resin particles have a smaller specific gravity than the mortar, it is preferable to mix the expanded synthetic resin particles into the mortar from below in order to uniformly mix the two.

As the expanded synthetic resin particles, for example, particles composed of polystyrene-based or polyolefin-based closed-cell expanded synthetic resin can be used. The particle size of the expanded synthetic resin particles is set to, for example, about 1 to 3 mm. or,
The expansion ratio of the expanded synthetic resin particles is preferably about 40 to 60 times.

By the way, not only is there a difference in the specific gravity between the mortar and the expanded synthetic resin particles, but since the affinity when mixing is not good, in order to make the mixing of the expanded synthetic resin particles and the mortar easier, The following measures can be considered.

(I) A synthetic polymer emulsion type adhesive is added in advance to water to be mixed with cement or the like in the mortar mixer 15.

(Ii) After adhering an aqueous solution containing a small amount of a surfactant to the expanded synthetic resin particles in advance, cement is contacted with the expanded synthetic resin particles, and a cement film is adhered and formed on the surface of the expanded synthetic resin particles. As a result, the affinity between the expanded synthetic resin particles and the mortar increases, and the difference in specific gravity decreases, so that mixing can be easily performed.

Foaming synthetic resin particles are supplied to the tank 20 from a foaming machine 45 by a pump 46. The foaming machine 45 stores an undiluted solution of synthetic resin and, if necessary, produces expanded synthetic resin particles from the undiluted solution.
In this way, if the expanded synthetic resin particles are produced at any time in the construction site, only a small amount of undiluted solution needs to be transported to the site, so the effort of transporting the expanded synthetic resin particles to the site one by one. There are advantages such as saving and drastically reducing transportation costs.

The resin-filled mortar 7 formed in the mixer 18 is pressure-fed to the construction position of the shield pit 3 by the mortar pressure feed pump 21 through the mortar pressure feed pipe 22 extending into the shield pit 3 through the vertical shaft 8. There is. A stabilizer or the like is added to the resin-containing mortar 7 as needed.

On the other hand, in the coagulant tank 23 in the coagulant supply unit 10,
A coagulant for rapidly solidifying the resin-containing mortar 7 is stored at the construction position in the shield pit 3. The coagulant is transferred to the adjusting tank 25 by the transfer pump 24, and is appropriately stirred here. The coagulant in the adjusting tank 25 is continuously supplied to the shield shaft 3 by the coagulant supply pump 26 via the vertical shaft 8.
It is adapted to be sent to a construction position in the shield pit 3 through a coagulant supply pipe 27 extending inward.

At the construction position in the shield pit 3, the resin-filled mortar 7 that is pumped by the mortar pumping pipe 22 and the coagulant that is supplied by the coagulant supply pipe 27 are mixed in the mortar filling member 28, and the holes of the segment 6 Backfilling is performed by filling the space between the segment 6 and the shield shaft 3 via 6a (FIG. 2).

Table 1 shows an example of the mixing ratio of mortar and the mixing ratio of mortar, expanded synthetic resin particles and coagulant.

Next, the control system will be described.

The kneading of cement, clay sand and water in the mortar mixer 15 is controlled by the kneading operation panel 30. or,
The mortar pressure-feeding pump 21 and the coagulant supply pump 26 pressure-feed the resin-filled mortar 7 and the coagulant into a two-liquid pressure-feed control panel 31
Controlled by. Further, the filling operation of the resin-filled mortar 7 in the shield pit 3 is configured to be remotely controlled by the remote operation panel 32 via the shield machine operating unit 33 installed in the shield pit 3. .

The shield machine operating unit 33, the remote control relay board 34,
An operation box 35 and a remote supply pressure operation panel 36 are provided. The supply pressure remote control panel 36 monitors the supply pressure between the resin-filled mortar 7 and the coagulant via the supply pressure monitoring device 37 provided in the mortar pressure feed pipe 22 and the coagulant supply pipe 27. .

In the construction device having the above configuration, the shield machine 1 excavates the shield pit 3 and the segments 6.6 ... Are sequentially arranged on the inner surface of the shielded pit 3 that has been excavated, so that the segments 6.6 ... Backfilling is performed by filling the space between and with the resin-containing mortar 7.

If this shield pit 3 is for laying waterworks, for example, then, as shown in FIG. 3, waterworks pipes 38 are installed in the segments 6 ... Then, the space between the segments 6, 6 ... And the water supply pipe 38 is filled with the resin-filled mortar 7 in the same procedure as the backfilling described above, and the filling is performed.

As a modification, the shield shaft 3 can be used as sewer. In that case, only the backfilling of the resin-filled mortar 7 between the segments 6, 6 ... and the inner surface of the shield pit 3 is performed, and the inner filling is not performed.
・ 6 ... is used as it is as a sewer pipe. The shield shaft 3 can also be used for laying various cables, for example. Since the shield shaft 3 used for laying a sewer pipe or a cable is used only for backfilling, it is included in the tunnel of claim 1 in the scope of claims.

[Example 2] Next, an example of a method for constructing a mountain tunnel included in claim 1 of the claims will be described.

As shown in Fig. 4, when constructing a mountain tunnel,
First, a horseshoe-shaped tunnel hole 50 is excavated in the natural ground 49 by an unillustrated excavator, and the resin-filled mortar 51 is sequentially sprayed onto the inner surface of the excavated tunnel hole 50. At this time, the resin-containing mortar 51 used for spraying is pressure-fed by the supply pipe as in the first embodiment, and is mixed with the coagulant separately supplied at the site.

Next, the segments 52, 52 ... Are arranged inside the inner surface of the tunnel hole 50 sprayed with the resin-filled mortar 51 at a predetermined interval, and adjacent ones are connected to each other to form a primary lining member. To do. Furthermore, inside the segments 52, 52 ...
After arranging an unillustrated center as a secondary lining member, the outer surface of the segment 52, 52 ... and the tunnel hole 50 sprayed with the resin-filled mortar 51 are inserted through the unillustrated holes provided in the segments 52, 52 ... The gap between the inner surface and the inner surface is filled with resin-filled mortar 53 to backfill.

By the way, at the time of the above-mentioned backfilling, the resin-filled mortar 53 becomes insufficiently filled in a portion where the space between the segments 52, 52 ... And the layer of the resin-filled mortar 51 on the inner surface of the tunnel hole 50 is large. Cavity 54 may occur. Such a cavity 54
If such a phenomenon occurs, the supporting strength of the tunnel hole 50 will decrease.

Therefore, after the resin-containing mortar 53 is solidified, a blind hole 55 is bored at an arbitrary position in the layer of the resin-containing mortar 53, and the blind hole 55
The resin-containing mortar 56 is fed in through. As a result, the cavity 54 is filled with the resin-containing mortar 56, so that the cavity 54 can be eliminated. In this embodiment, the blind hole 55 is formed after the resin-containing mortar 53 is solidified. However, before the resin-containing mortar 53 is filled, the blind hole 55 is formed between the segments 52, 52 ... And the inner surface of the tunnel hole 50. A pipe for injecting the resin-filled mortar 56 for refilling may be arranged.

〔The invention's effect〕

As described above, the method for constructing a tunnel according to claim 1 in the scope of the claims of the present specification is such that the mortar is mixed with the expanded synthetic resin particles prior to the pressure feeding, and at the time of mixing, Mortar is injected from the top of the mixer, while expanded synthetic resin particles are injected from the bottom.

As a result, the expanded synthetic resin particles are mixed into the mortar for backfilling or inside filling that is pumped into the tunnel.
Upon mixing, mortar is injected from the top of the mixer, while expanded synthetic resin particles are injected from the bottom. That is, since the expanded synthetic resin particles have a smaller specific gravity than the mortar, the expanded synthetic resin particles can be mixed uniformly by mixing the expanded synthetic resin particles from below the mortar.

Further, during pressure feeding, the expanded synthetic resin particles do not dissipate into the atmosphere due to the pressure for pressure feeding or disappear from the mortar during long-distance pressure feeding, so the volume of the mortar decreases and the specific gravity decreases. Does not increase. further,
By uniformly mixing the expanded synthetic resin particles with the mortar, it is possible to prevent the decrease in fluidity of the non-uniform portion, which has been conventionally caused. Therefore, when the mortar is pressure-fed, it is possible to secure a sufficient pressure-feeding capability and easily supply the mortar even over a long distance of, for example, about 2 km. Further, by preventing the volume of the mortar from decreasing during the pressure feeding, there is an effect that the consumption amount of the mortar can be suppressed and the construction cost can be reduced.

Moreover, the construction method of the tunnel described in claim 2 is
This is a method in which expanded synthetic resin particles are mixed into the mortar prior to pressure feeding, and at the time of mixing, a cement film is adhered and formed on the surface of the expanded synthetic resin particles in advance.

As a result, by adhering a cement film to the surface of the expanded synthetic resin particles in advance during mixing, the affinity between the expanded synthetic resin particles and mortar increases, and the difference in specific gravity between the expanded synthetic resin particles and mortar is increased. Therefore, uniform mixing can be easily performed.

Therefore, it is possible to ensure a sufficient mortar pressure-feeding ability and to suppress the consumption of mortar.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention, FIG. 1 is an explanatory view showing the overall construction of a shield pit construction apparatus, and FIG. 2 is an enlarged explanatory view of the main parts of the construction apparatus. FIG. 3 is a schematic vertical sectional view in a completed state when the shield shaft is for waterworks, and FIG. 4 is a schematic vertical sectional view of a mountain tunnel in the second embodiment. 3 is a shield pit (tunnel), 6/52 is a segment (lining material), 7/51/53/56 is resin-filled mortar, 9 is a mortar pumping section, and 50 is a tunnel hole.

Claims (2)

[Claims] 1. A method for constructing a tunnel in which mortar is pressure-fed through a portion where the tunnel has already been constructed, and the mortar that has been pressure-fed is backfilled inside or inside the lining material. A method for constructing a tunnel, wherein expanded synthetic resin particles are mixed, and at the time of mixing, mortar is injected from the upper part of the mixer, while expanded synthetic resin particles are injected from the lower part. 2. A method for constructing a tunnel in which mortar is pressure-fed through a portion where the tunnel has already been constructed, and the pressure-fed mortar is backfilled inside or inside the lining material. A method for constructing a tunnel, characterized in that expanded synthetic resin particles are mixed, and at the time of mixing, a cement film is adhered and formed on the surface of the expanded synthetic resin particles in advance.