JPH0784836B2 - Pedestal ring for press jack installation of shield machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a tunnel construction technique for in-situ casting concrete, and more specifically to a pedestal ring in a cast-in-place lining method.

<Prior Art> In constructing a shield tunnel, there are a method of assembling ready-made segments on site and a method of placing concrete on site using a formwork.

The present invention relates to the latter construction technique.

Generally, when concrete is cast in situ, an inner formwork is arranged inside a tail plate of a shield machine, and a plate material called a gable plate is installed between the end of the inner formwork and the tail plate to form a framework.

<Problems to be Solved by the Present Invention> Considering the outflow of fresh concrete, the gap between the end plate and the inner peripheral surface of the tail plate cannot be set large.

Since the distance between the inner peripheral surface of the tail plate and the end plate is extremely small as described above, the end plate interferes with the operation of the shield machine when the excavation method is corrected or a curve is constructed, and the maneuverability of the shield machine is deteriorated.

In particular, when the curvature of the curve becomes small, the construction may become impossible.

In addition, the gable plate and the tail plate do not compete with each other when correcting the excavation direction or when making a curve.

Further, in the cast-in-place lining method, concrete is pressed at a high pressure in the tail plate, so that it is necessary to increase the cross section of the press ring or reduce the interval between the tie rods.

<Purpose of the present invention> The present invention has been made in view of the above points. The shield machine is excellent in maneuverability even when the excavation direction is corrected or when a curve is constructed, and the cross section of the press ring can be downsized. It is an object of the present invention to provide a pedestal ring in a cast-in-place lining method that can reduce the installation interval of the.

<Structure of the Present Invention> (a) Press Ring The press ring 1 is of a prefabricated type for the purpose of prestressing the lining in cooperation with the tie rods 2 and being buried to reinforce the tunnel lining. It is a ring member.

An example of the press ring 1 is shown in FIGS.

This press ring 1 is formed by arranging cylindrical ribs 12 having different diameters in two rows in parallel on one side of a disc-shaped ring plate 11.

Further, a plurality of holes 13 for penetrating the tie rods 2 are formed on the plate surface of the ring plate 11.

In order to improve the maneuverability of the shield machine 4, the plate width of the ring plate 11 is set smaller than the working thickness of the lining.

When the plate width of the ring plate 11 is reduced, the gap between the tail plate 41 of the shield machine 4 and the inner formwork 5 is increased, and the outflow of fresh concrete is expected. Conversely, when the plate width of the ring plate 11 is increased. It is expected that the maneuverability of the shield machine will deteriorate when the direction is corrected or when a curve is constructed.

Therefore, in the present invention, first, the plate width of the ring plate 11 is reduced to avoid contact with the respective surfaces of the tail plate 41 and the inner formwork 5, and the maneuverability of the shield machine 4 is ensured.

Then, the pedestal ring 3 described below is used to control the outflow of fresh concrete.

(B) Pedestal ring (Figs. 3 and 4) The pedestal ring 3 is a disk that is repeatedly used for each span, and is installed in the shield machine 4 for use.

The pedestal ring 3 has a hat-shaped cross section, and has a pedestal surface 31, support legs 32 extending to both ends of the pedestal surface 31, and grounding surfaces 33 extending from the respective support legs 32 in parallel with the pedestal surface 31.

An annular gap that matches the press ring 1 is provided in the center of the ground contact surface 33 to restrict the radial movement of the press ring 1.

Further, the inner diameter of the ground contact surface 33 is smaller than the inner diameter of the press ring 1 and the outer diameter is larger than the outer diameter of the press ring 1, so that the concrete cover allowance of the press ring 1 is kept constant.

The plate surface of the pedestal surface 31 has insertion holes 34 formed at the same positions as the holes 13 of the press ring 1 and working holes 35 formed on both sides of each insertion hole 34.

The insertion hole 34 is a dedicated hole for inserting the tie rod 2, and the working hole 35 is a working hole for tightening the fixing tool 21 described later.

The length of the support leg 32 is such that when the rib 12 is directed to the support leg 32 and the press ring 1 is tied together, the tip end surface of the rib 12 is the pedestal surface 31.
The jack pressure is set to a length that can disperse and transmit the jack pressure to the press ring 1 mainly through the ribs 12 by grounding on the back side of the.

A rubber packing is attached to the grounding surface 33 so that it can be brought into close contact with the ring plate 11 when tying it together with the press ring 1.

The inner and outer diameters of the grounding surface 33 are formed so as not to come into contact with the respective surfaces of the inner mold 5 and the tail plate 41, as shown in FIG.

Further, an expansion / contraction seal 36 that can freely adjust the ground contact width of the ground contact surface 33 by taking in and out pressurized fluid is continuously provided on the outer end surface of the ground contact surface 33.

That is, the expansion / contraction seal 36 is formed so as to shield the space area that cannot be shielded by the press ring 1 by the expansion operation, and to secure a gap between the inner mold 5 and the tail plate 41 by the contraction operation of the expansion / contraction seal 36.

(C) Press Jack The press jack 6 is used by being installed on the pedestal ring 3, and for example, a center hole type jack or the like can be used.

<Operation of the present invention> Next, a tunnel construction method will be described.

(A) Extension of tie rod Figure 5 shows the end of the lining 7a constructed in the previous step.

The press ring 1 and the tie rod 2a are exposed at the end of the lining 7a, and the fixing tool 21 is provided at the end of each tie rod 2a.
Is attached.

To splice a new lining on this lining 7a, first tie rod 2a protruding from the existing lining 7a.
The connection tool 22 is screwed onto the and the tie rod 2b is connected.

(B) Assembly of rings (FIG. 5) Next, the press ring 1 divided into the tunnel is carried in and assembled in the tail plate 41 of the shield machine 4 in a ring shape.

When the press ring 1 is assembled, each tie rod 2a is passed through the hole 13 of the press ring 1 as shown in FIG.

Next, the pedestal ring 3 is mounted on the press ring 1, and the press jacks 6 are set on the tie rods 2 that are exposed by penetrating the insertion holes 34 of the pedestal ring 3.

(C) Assembly of formwork The inner formwork 5 is assembled inside the tail plate 41.

(D) Press-fitting of concrete (Fig. 6) The expansion / contraction seal 36 of the pedestal ring 3 is expanded to form a shielded space between the inner formwork 5 and the tail plate 41.

Concrete 7b is poured into the entire shielded space from a concrete injection pipe connected to the inner formwork 5.

(E) Pressurization of concrete (Fig. 7) Next, when the press jacks 6 are simultaneously actuated to pull the tie rods 2b, the concrete 7b is pressurized and excess water in the concrete 7b is drained.

During pressurization of the concrete 7b, the expansion / contraction seal 36 provided on the pedestal ring 3 expands to come into contact with the respective surfaces of the tail plate 41 and the inner formwork 5 to restrict the outflow of the concrete 7b.

(F) Shield excavation (Fig. 8) The shield machine 4 is advanced while extending the excavation jack 42 provided on the shield machine 4 side to obtain a reaction force to the inner formwork 5.

Then, at the same time as the shield machine 4 moves forward, the tail plate 41 is moved to the face side.

As a result, the concrete is pressed against the ground exposed by the passage of the tail plate 41.

Pressing with the press jack 6 is continued until the concrete 7b comes into close contact with the ground.

(G) Fixing of press ring When the predetermined strength is developed in the concrete, the working hole 35 of the pedestal ring 3 is used to tighten the fixing tool 21 to fix the press ring 1.

As the fixing tool 21, a screwing type, a wedge type, or a type in which depressions are arranged on the outer circumference of the tie rod 2 and a clip type that can be mounted from the lateral direction of the tie rod 2 can be adopted.

(H) Removal of pedestal rings After the fixing work of the press ring 1 is completed, the pedestal ring 3 is removed together with the press jack 6.

By repeating the above steps, the linings are successively spliced to construct a predetermined tunnel.

(I) When making a curve and correcting the direction When making a curve on the tunnel or correcting the direction of excavation, the expansion / contraction seal 36 is applied according to the direction of excavation of the shield machine 4.
By adjusting the expansion amount and adjusting the clearances at both ends of the inner and outer circumferences of the pedestal ring 3, the shield machine 4 is allowed to move freely, so that the shield machine 4 can be installed smoothly.

<Other Example 1> In the above examples, the case where the reaction force at the time of excavation of the shield machine 4 is obtained from the inner formwork 5 has been described, but the following method can be adopted.

(1) A method of directly obtaining reaction force of excavation from fresh concrete that has been placed.

(2) A method of obtaining a reaction force from the hardened lining constructed several spans ago.

<Other Example 2> In the above example, the case where the sealing material having the expansion / contraction function is used as the outflow preventing means of fresh concrete has been described, but it is also possible to use a known O-ring as another sealing material. .

<Effects of the Present Invention> Since the present invention is as described above, the following effects can be obtained.

(A) The finished surface of the lining can be finished neatly.

(B) Curve construction can be done smoothly.

(C) The width of the press ring that presses the concrete cast in-situ into the shield is formed smaller than the width between the inner surface of the tail plate and the outer surface of the inner mold form in consideration of the curve construction of the shield.

Therefore, when the press ring is moved to press the concrete, a position of the press ring is displaced and a portion where the concrete cover amount is thin occurs, which is a structural problem.

Therefore, according to the present invention, an annular gap that matches the press ring is provided in the center of the grounding surface of the pedestal ring to restrict the radial movement of the press ring.

Further, the inner diameter of the ground contact surface is smaller than the inner diameter of the press ring, and the outer diameter is larger than the outer diameter of the press ring, so that the concrete cover allowance of the press ring is kept constant.

Furthermore, considering things such as the curve construction of the shield,
It is possible to prevent the concrete from flowing out by providing expandable and contractible sealing materials on the inner and outer circumferences of the grounding surface so as to follow the change in the width between the inner surface of the tail plate and the outer surface of the inner formwork.

(D) Since the force of the press jack is distributed and transmitted, the interval between the tie rods and the cross section of the press ring can be reduced.

[Brief description of drawings]

Figure 1: Longitudinal section of tunnel Figure 2: Front view of press ring Figure 3: Front view of pedestal ring Figure 4: Explanatory drawing when assembling press ring and pedestal ring Figure 5: Pouring concrete Fig. 6: Illustration of concrete injection process Fig. 7: Illustration of concrete pressurization by press jack Fig. 8: Concrete pressurization process during excavation of the shield machine Illustration

Front Page Continuation (72) Inventor Koji Maeda 1-16-22 Naruse, Machida, Tokyo (56) Reference JP 62-45899 (JP, A) JP 56-85095 (JP, A) JP Showa 47-9474 (JP, B1)

Claims (1)

[Claims] 1. A pedestal ring for installing a press jack for pressurizing cast-in-place concrete in a shield machine, having a through-hole for inserting a reinforcing material arranged in cast-in-place concrete, and installing a press jack. Surface, the support legs extending to both ends of the base surface, the support legs extending in parallel to the base surface, and an annular gap for matching the press ring at the center of the support ring. A press for a shield machine, which comprises a ring body having a grounding surface having a smaller inner diameter than that of the press ring and a larger outer diameter than the outer diameter of the press ring, and the expandable and contractible sealing material is provided on the inner circumference and the outer circumference of the ring body, respectively. Pedestal ring for jack installation.