JPH05156895A - Concrete jointing method for tunnel covering concrete - Google Patents

Abstract

PURPOSE:To improve initial strength and durability of concrete substantially by ensuring discharge of excess water from jointed concrete which has not hardened yet. CONSTITUTION:This is a method of jointing fresh concrete with already applied concrete 10 by supplying the fresh concrete 11 into a space 15 defined by a form 12 for tunnel covering work and the inner circumferential surface 14 of the tunnel. Filters 20a and 20b having water discharging function are attached to the joint surface 16 and/or gable surface 17 so as to discharge excess water from the fresh concrete 11. The fresh concrete 11 which has been supplied into the space 15 but has not hardened yet is pressurized by side pressure even at end portions of the space 15 where concrete may stand still, and excess water in the concrete is discharged through the filters 20a and 20b from slits 22a and 22b and the like formed in lower parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method of casting concrete using a formwork for tunnel lining.

[0002]

Prior art and its problems: In the lining of various tunnels, between the inner surface of the ground (or the segment, the primary lining portion of shotcrete) and the outer surface of the tunnel lining formwork (centre). Concrete is pumped into the space formed in the building to form the tunnel lining concrete. For example, when constructing an arch concrete for a tunnel using an arch-shaped centle, as shown in the tunnel cross-sectional view of FIG. 6, a fresh concrete is pumped by a concrete pump on an inspection window that can be opened and closed provided on the side wall of the centle. And a blow-up type injection port 2 provided at the top of the center. Then, the fluid fresh concrete is from the bottom of the center to the legs,
The side wall, shoulder, and top end rise in sequence.

It is necessary to compact concrete in order that the cast concrete exhibits a predetermined strength. The concrete can be compacted up to the shoulder portion by projecting a bar-shaped vibrator from the inspection window, but it is difficult to perform compaction at the top end portion. That is, at the top end, as shown in FIG. 7, concrete naturally flows from the inlet 2 along the outer surface 3 of the center and the inner surface 4 of the ground (or the segment, the primary lining portion of the shotcrete). It is only injected and filled in the state. Therefore, in the splicing section 5 and the end plate section 6 with the existing hardened concrete, the flow of concrete is stagnant and stagnates, and the compaction process is not performed.
It will be hardened and cured.

Therefore, conventionally, the following problems have occurred. When fluid is flowed into a tunnel such as a headrace tunnel or a drainage tunnel regardless of the presence or absence of pressure, the joint part of the tunnel lining concrete is easily damaged, and when pressure is applied, especially when there is pressure fluctuation. Has a tendency to be largely damaged at the splice portion at the top end. Also,
Even in road tunnels and railway tunnels, the concrete at the top joint part may peel off and fall under the influence of wind pressure and vibration.

Regarding compaction of concrete, it may be considered that a wall-mounted vibrator is attached to the inner surface of the center and the concrete in contact with the center is vibrated to be compacted. However, there is little effect even if the fresh concrete having a high slump value is momentarily vibrated, and if it is vibrated for a long time, the concrete in contact with the centle may be separated and the quality may be deteriorated.

On the other hand, it is well known that the strength and durability of concrete are enhanced by discharging excess water and air in uncured concrete. The applicant of the present application previously provided water passage holes in the face plate constituting the center,
On the side of the face plate that contacts the concrete, we proposed a centle with a dewatering function that has a filter that allows the passage of excess water in the uncured concrete immediately after casting and prevents the passage of cement particles in the concrete ( JP 62
280451). However, as described above, the problem actually required in the tunnel lining concrete is to improve the quality of the joint portion of the concrete having a small thickness.

[0007]

OBJECT OF THE INVENTION The purpose of the present invention is to splice concrete in a tunnel lining concrete, which can surely discharge excess water in the uncured concrete that has been spliced, thereby significantly improving the initial strength and durability of the concrete. To provide a construction method.

[0008]

According to the present invention, concrete is supplied into a space defined by a tunnel lining form and a tunnel inner peripheral surface,
In a method of joining existing lining concrete, a filter that allows the passage of excess water in the uncured concrete immediately after placing and blocks the passage of cement particles in the concrete, is a joining surface with the existing concrete. And / or sticking to the end plate surface to discharge excess water in the uncured concrete.

[0009]

The uncured fresh concrete supplied into the space is compacted by the action of the lateral pressure even at the end of the space where the concrete tends to stand still, and excess water in the concrete has the drainage function. It is discharged from a slit or the like formed below the filter.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. In the drawings, the tunneling direction side is called front, front, front, etc., and the opposite side is rear, rear,
It is called the rear surface. FIG. 1 is a partial vertical cross-sectional side view in the central portion of the tunnel showing a state in which fresh concrete 11 is spliced onto existing tunnel lining concrete 10. In the figure, an arch-shaped space 15 between the face plate 13 of the tunnel lining formwork 12 and the tunnel inner peripheral surface 14 of which the supporting work is omitted is shown. The rear end surface of the arched space 15 is a joint surface 16 with the existing concrete 10. Therefore, the front end face is defined by the end plate 17.

Filters 20a and 20b are attached to the insides of the connecting surface 16 and the end plate 17 (in the space 15). As the filters 20a and 20b, those made of geotextile such as woven cloth and non-woven cloth can be used.
The filter disclosed in 5467 is particularly preferred. The filters 20a, 20b allow passage of excess water and air in the uncured concrete and prevent passage of cement particles in the concrete. The filters 20a and 20b are composed of the entire connecting surface 16 and the fresh concrete 11 of the end plate 17.
It is affixed to a range where they contact, that is, a vertical surface forming the space 15. As a method of sticking, a method such as an adhesive, a double-sided adhesive tape or nailing is used.

Reference numerals 22a and 22b denote filters 20a and 20a.
20b is a slit formed by sticking 20b downward from the filter.
Excess water that has passed through 0b and flows out is in the slit 22.
It is discharged to the outside via a and 22b. Reference numeral 23b is a water passage hole that penetrates both inner and outer surfaces of the end plate 17, and has the same function as the slit 22b. Also, reference numeral 24
Is a spacer for facilitating the formation of the slits 22b, and the mounting plate 18 of the tunnel lining formwork 12 and the end plate 1
7 and the filter 20b so that a space equal to or larger than the thickness of the filter 20b can be maintained.

In FIG. 1, the uncured fresh concrete supplied into the space 15 is consolidated by the action of the lateral pressure at the front end and the rear end where it is likely to remain stationary and the slits 22a, Excess water in the concrete is discharged from 22b and the water passage hole 23b. The filter 20b attached to the end plate 17 can be used again as the filter 20a when the next splicing surface 16 is constructed without being removed from the concrete after the mold is removed.

In another embodiment shown in FIG. 3, the filter is further attached to the front end and the rear end of the face plate 13, and the filling space 15 near the splicing face 16 and the end plate 1.
The function of discharging excess water from the 7th side is promoted. It is sufficient that the portions to which the filters 20c and 20d are attached are within a range of about 30 cm from each end.

FIG. 4 shows a case where joints 26 are provided in the jointing portion of the lining concrete, and the jointing method of the present invention is modified so that the filter 20e is attached to the inclined surface 13 of the face plate 13.
It can be dealt with by sticking along a.

As described above, the position where it is difficult to compact the lining concrete is within the range of 45 degrees from the top end to the left and right around the tunnel axis. Therefore, FIG.
As shown in FIG. 5, if the filters 20a and 20b are attached within a range of approximately 60 degrees to the left and right from the top end with the tunnel axis 30 as the center, the effect of discharging the excess water becomes large.

[0017]

EFFECTS OF THE INVENTION The splicing method for tunnel lining concrete according to the present invention ensures the surplus water in the spun uncured concrete by devising the attachment position of the filter having the surplus water discharging function. It can be discharged, and the strength and durability of concrete can be greatly improved.

[Brief description of drawings]

FIG. 1 is a partial vertical cross-sectional side view in a central portion of a tunnel showing a concrete splicing method.

FIG. 2 is a view showing the top of the tunnel, the left half of which is a front end view, and the right half of which is II-II in FIG.
It is a line vertical section front view.

FIG. 3 is a partially longitudinal side view of a tunnel central portion showing another embodiment.

FIG. 4 is a partial vertical cross-sectional side view in a central portion of a tunnel showing a modified example in which joints are provided in a joint portion.

FIG. 5 is a tunnel cross-sectional view showing a preferable attachment range of filters 20a and 20b.

FIG. 6 is a sectional view of a tunnel showing a flow state of fresh concrete at a top end portion.

FIG. 7 is a vertical side view taken along the line VII-VII of FIG.

[Explanation of symbols]

 10 (hardened) existing concrete 11 (uncured) fresh concrete 12 tunnel lining formwork 13 face plate 16 joint surface 17 gable plate 20a, b, c, d, e filter 22a, b slit 23b, c, d water passage hole

Claims (2)

[Claims] 1. In a construction method in which concrete is supplied into a space defined by a tunnel lining formwork and an inner circumferential surface of the tunnel and the existing lining concrete is spliced, surplus of uncured concrete immediately after casting is surplus. Attaching a filter that allows the passage of water and blocks the passage of cement particles in the concrete to the splicing surface with the existing concrete and / or the end plate surface to discharge excess water in the uncured concrete. Tunnel lining concrete jointing method characterized by. 2. A slit is formed downward from the filter having the drainage function.
Tunnel splint concrete splicing method described.