JP2001123794A - Tunnel lining method and arch center therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tunnel lining method capable of preventing the occurrence of cracks at a portion overlapped with an arch center at the secondary lining concrete previously poured by the bearing of the arch center. SOLUTION: In sequentially placing secondary lining concrete throughout the whole length of a tunnel by using an arch center, an end portion where the arch center is overlapped is heated at the time of placing subsequent secondary lining concrete at the secondary lining concrete placed between the placement of the secondary lining concrete and the removal of form, and a required compressive strength is created at this end portion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tunnel lining method in which secondary lining concrete is sequentially poured over the entire length of the tunnel by using a centre, and a centr used for the tunnel lining method.

[0002]

2. Description of the Related Art The general work process of tunnel construction is roughly divided into mining by excavation of ground, primary lining by construction of steel support or spraying of mortar, and secondary lining by casting concrete. The secondary lining forms a finished cross section and is generally referred to as lining.

Conventionally, the secondary lining concrete is cast, for example, as shown in FIG. 4, a gate-shaped base 33a which can run on a rail 32 laid in a tunnel 31, and a base 33a.
It is provided on the upper part via a jack 33b so as to be able to go up and down,
The upper half foam panel 33c along the upper half of the tunnel 31 and both sides of the upper half foam panel 33c are bendably connected to each other, and are connected to the side wall of the tunnel 31 via jacks 33d. Using a centrifuge (steel movable large formwork) 33 which is provided so as to be able to advance and retreat, and is roughly constituted by a side wall foam panel 33e shaped along the side wall of the tunnel 31; Primary lining method 34 and foam panel 3
The placement of the secondary lining concrete between the tunnels 3c and 33e and the movement of the center 33 are sequentially repeated to perform the entire length of the tunnel 31. Then, as shown in FIG. 5, when the center 33 is moved from the already-placed position of the secondary lining concrete 35 to the next placement position, and set, the next secondary lining concrete is already placed. Secondary lining concrete 3
5, a part of the center 33 is overlapped with the end of the next secondary lining concrete in the already laid secondary lining concrete 35 on the side where the next secondary lining concrete is laid (the left side in FIG. 5), and In order to prevent the concrete from leaking from the overlapping portion during the placement of the next secondary lining concrete, the foam panels 33c and 33e are pressed against the already placed secondary lining concrete 35.

[0004] The construction of the secondary lining concrete is sequentially performed over the entire length of the tunnel after the completion of the tunnel digging and the primary lining, so that it is necessary to complete the construction in the shortest possible period. Therefore, from concrete placement
The construction time of one cycle from the movement of the center to the setting of the center is about two days. In addition, the time from the completion of placing concrete to the removal, movement, and setting of the center is about 15 hours.

[0005]

However, according to the conventional tunnel lining method and the centru used therefor, in order to avoid the formation of a gap between the overlapping centur 33 and the secondary lining concrete 35, it is necessary to use a conventional method. Wrap the foam panels 33c and 33e in the jack 33
b and 33d, when the bearing is strongly supported, the secondary lining concrete 35 is cast so that the next secondary lining concrete is cast last, so that the curing time is short. When the compressive strength of the secondary lining concrete 35 at the overlap portion is not sufficiently developed (for example, when the compressive strength is less than 5 N / mm ² ), cracks 36 are easily generated as shown in FIG. . As shown in FIG. 6, the occurrence of the cracks 36 becomes remarkable, in particular, when the line of the tunnel 31 is curved, the end of the center 33 and the already laid secondary lining concrete 35 compete with each other. . Since the crack 36 is still hidden by the center 33, it is difficult to find it. The cracks 36 are local and do not immediately impair the function of the secondary lining concrete 35, but cause peeling and dropping of the secondary lining concrete 35 due to long-term deterioration. Peeling or falling off of the secondary lining concrete 35 must be avoided because it would harm a third person passing through the tunnel 31.

Accordingly, the present invention is directed to a tunnel lining method capable of preventing the occurrence of cracks at the overlapped portion with the centrifugal in the secondary lining concrete that has already been cast by the bearing of the centur, and a centrifugal lining used for the tunnel lining. The purpose is to provide.

[0007]

In order to solve the above-mentioned problems, a tunnel lining method according to the present invention is applied to a case where secondary lining concrete is sequentially poured over the entire length of the tunnel by using a centrifugal, and a secondary lining concrete is used. During the time between the placement of the concrete and the removal of the centre, the end of the placed secondary lining concrete where the centruel overlaps when the next secondary lining concrete is poured is heated, and this end is heated. The part is characterized by exhibiting a required compressive strength. The required compressive strength is preferably 5 N / mm ² or more.

On the other hand, a tunnel lining method is a centr used for sequentially placing secondary lining concrete over the entire length of the tunnel, and is used for placing the next secondary lining concrete on a foam panel. A heater is attached to the inner surface of the side end. It is preferable that a heat insulating material is provided on the inner surface of the foam panel so as to cover the heater beyond the area where the heater is provided. The heater is
The foam panel is preferably provided over the entire length in the circumferential direction, and is preferably divided into a plurality of blocks in the circumferential direction. Preferably, the heater is provided with a controller for automatically controlling the temperature rise and fall.

If the required compressive strength is less than 5 N / mm ² , there is a possibility that cracks may occur in the overlapped portion of the already laid secondary lining concrete when the centur is overlapped and supported. .

The area where the heater is provided is preferably 20 to 30 cm corresponding to the width of the overlapped portion. The area of the heat insulating material beyond the area where the heater is provided is preferably 20 to 50 cm.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are a perspective view of an essential part showing an example of an embodiment of a tunnel lining method according to the present invention, and a sectional view taken along line II-II in FIG. In the figure, reference numeral 1 denotes a foam panel constituting a part of the center, which is not shown, but is provided via a jack on a top of a gate-shaped pedestal which can run on a rail laid in the tunnel so as to be able to go up and down, and The upper half foam panel and the upper half foam panel along the upper half are connected to both sides of the upper half foam panel in a freely bendable manner, and are provided so as to be able to advance and retreat via a jack to the side wall of the tunnel, And a side wall foam panel shaped along the side wall of the tunnel.

A heater 2 is provided at the front end of the foam panel 1 in the direction of travel of the centre, that is, at the inner surface of the end on the side where the next secondary lining concrete is to be poured, when the next secondary lining concrete is poured. It has a width (for example, 20 to 30 cm) equivalent to the width of the rear end portion in the traveling direction of the sentre that is overlapped with the already placed secondary lining concrete, and is provided over the entire circumference. The heater 2 is used to heat the secondary lining concrete in the overlap portion through the foam panel 1 to increase its initial curing temperature, and is divided into a plurality of blocks in the circumferential direction of the foam panel 1.
The heater 2 includes a controller 3 for automatically controlling the temperature rise and fall of an arbitrary block. Further, the inner surface of the foam panel 1 at the end on the side where the next secondary lining concrete is cast is used to prevent wasteful heat dissipation from the heater 2 and to prevent the secondary lining concrete from overlapping with the overlapping portion. In order to prevent the temperature difference between adjacent portions from increasing, the heater 2 is moved beyond the area where the heater 2 is provided (for example, 2 mm).
A heat insulating material (for example, a fire-resistant heat insulating material) 4 to be coated is provided.

In order to perform secondary lining of the tunnel using the centr having the above structure, first, the bur is moved to a required position in the tunnel where the pit and the primary lining have been completed, set, and then the secondary lining is performed. Cast concrete. Next, the controller 3 controls the temperature rise and fall of the heater 2 so that the end of the secondary lining concrete on the casting side of the next secondary lining concrete has a required compressive strength (for example, While heating to 5 N / mm ² ) or more, cure the secondary lining concrete. The temperature rise and fall of the heater 2 by the controller 3 is, for example, as shown in FIG.
Preliminary time (about 2 hours) from the placement of the secondary lining concrete to the start of heating, the required heating temperature (for example, 40
° C), a heating time at a required heating rate (for example, 10 ° C / hour), a holding time at a required heating temperature, and a cooling time at a required cooling rate (for example, 10 ° C / hour). You. Next, when the curing of the secondary lining concrete is completed, the center is removed from the mold, moved to the casting side of the next secondary lining concrete, and the rear end of the moving direction in the traveling direction is the secondary lining of the already laid concrete. The concrete is set so as to overlap with the end of the concrete, a secondary lining concrete is cast, and the same process is repeated over the entire length of the tunnel.

Incidentally, the curing temperature, time and compressive strength of the concrete used as ordinary secondary lining concrete, when the underground temperature (concrete temperature) is 20 ° C., is about 1.5 N / mm at a curing time of 15 hours. ^{2. The} curing time is about 3.0 N / mm ² for 24 hours, but if the concrete temperature is 30 ° C., the curing time is about 3.0 N / mm ^{2 for} 15 hours.
0N / mm ^2, is about 9N / mm ² approximately in curing time 24 hours, also, when the concrete temperature is 40 ° C., about 9N / mm ² in curing time 15 hours, about 12N / mm ² approximately in curing time 24 hours Becomes Therefore, in order to make the compressive strength of the end where the centru overlaps at the time of placing the next secondary lining concrete in the already laid secondary lining concrete 5 N / mm ² or more, a temperature of about 40 ° C. Hold for about 13 hours.

[0015]

As described above, according to the tunnel lining method of the present invention and the sentence used therein, during the curing of the already laid secondary lining concrete, the next secondary lining concrete is poured. Since the end of the pre-cast secondary lining concrete that sometimes overlaps with the centre has the required compressive strength, no cracking occurs even if the centre bearing pressure acts on this end. In addition, the curing time of the secondary lining concrete is the shortest, and the strength development of the wives where the support of the centre acts acts is promoted more than other parts, so the curing time of the secondary lining concrete can be shortened. It is possible to shorten the tunnel lining period. On the other hand, by providing a heat insulating material on the inner surface of the foam panel to cover the heater beyond the area where the heater is provided, unnecessary heat radiation from the heater can be prevented, and the overlap of the secondary lining concrete and the vicinity thereof can be prevented. It is possible to prevent the temperature difference in the portion from becoming large, and to shorten the curing time in this portion. Further, since the heater is provided over the entire length of the foam panel in the circumferential direction and is divided into a plurality of blocks in the circumferential direction, each block can be set to an individual required temperature. Furthermore, since the heater is provided with a controller that automatically controls the temperature rise and fall, the strength of the overlap portion with the centre in the secondary lining concrete can be unmanned.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part showing an example of an embodiment of a tunnel lining method according to the present invention.

FIG. 2 is a drawing viewed from arrows II-II in FIG.

FIG. 3 is an explanatory diagram showing an operation of a controller in the sentence of FIG. 1;

FIG. 4 is a schematic front view of a conventional center.

FIG. 5 is a cross-sectional view showing an operation at the time of lining a tunnel using the sentence of FIG.

FIG. 6 is a cross-sectional view showing another operation at the time of lining a tunnel using the sentence of FIG. 4;

[Explanation of symbols]

 1 Foam panel 2 Heater 3 Controller 4 Insulation material

Claims (6)

[Claims] When a secondary lining concrete is sequentially poured over the entire length of a tunnel using a centur, the secondary lining concrete is poured from a time after the secondary lining concrete is poured to a time when the centur is removed. A method of lining a tunnel, comprising heating an end portion of the second lining concrete where the centruel is overlapped at the time of placing the next second lining concrete, and developing a required compressive strength at the end portion. 2. The tunnel lining method according to claim 1, wherein the required compressive strength is 5 N / mm ² or more. 3. A sentence which is used for sequentially placing secondary lining concrete over the entire length of a tunnel, wherein the inner surface of the foam panel at the end of the next secondary lining concrete is placed. A centr for tunnel lining, which is provided with a heater. 4. A tunnel lining method according to claim 3, wherein a heat insulating material is provided on an inner surface of the foam panel so as to cover the heater beyond an area where the heater is provided. 5. The tunnel covering according to claim 3, wherein the heater is provided over the entire length of the foam panel in the circumferential direction, and is divided into a plurality of blocks in the circumferential direction. Center for construction method. 6. The tunnel lining method according to claim 3, wherein the heater is provided with a controller for automatically controlling a temperature rise and fall of the heater.