JPH01190899A - Cast-in-place shield excavator - Google Patents

Abstract

PURPOSE:To perform smooth formation of a curve having a small radius, by a method wherein an annular end plate is brought into contact with the inside of a tail plate and freely movable in a circumferential direction in an annular box. CONSTITUTION:An inner form 5 is annularly positioned at the rear of the inside of a shield excavator 4. The shield excavator 4 is advanced by exerting a reaction force on the inner form 5. Outflow of concrete 7 from the end side is blocked by means of a press ring formed with an annular box 3 and an annular end plate 8. The annular end plate 8 is brought into contact with a tail plate 41 and is freely movable in the annular box 3 to perform normally complete blocking of the end side.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a shield excavator constructed by pouring concrete on-site.

<Conventional Technology> There are two methods for constructing a shield tunnel: one is to assemble ready-made segments on-site, and the other is to use formwork to pour concrete on-site.

The present invention relates to the latter construction technique.

Generally, when pouring concrete on-site, an inner formwork is placed behind the tail plate of the shield excavator, and the formwork takes the reaction force to advance the excavator, and at the same time places concrete between the formwork and the ground. A shield tunneling machine is used.

In this case, a frame is formed by arranging a plate material generally called a end plate between the face side end of the inner formwork and the tail plate.

Problems to be solved by the present invention> The conventional technology has the following problems.

That is, considering the outflow of fresh concrete, the distance between the end plate and the inner circumferential surface of the tail plate cannot be set large.

Since the distance between the inner circumferential surface of the tail plate and the end plate is thus very small, the end plate becomes an obstacle when correcting the excavation direction or constructing a curve, resulting in poor maneuverability of the shield excavator.

In particular, if the radius of the curve is small (sometimes construction becomes impossible).

Purpose of the Invention The present invention was made in view of the above points, and an object thereof is to provide a shield excavation machine with excellent operability even when modifying the excavation direction of the shield excavation machine and when constructing curves. do.

<Configuration of the Present Invention> An embodiment of the present invention will be described below with reference to the drawings.

<A> Configuration of the entire device (Fig. 1) An inner formwork 5 is placed in an annular shape at the rear inside of the shield tunneling machine 4.

The shield tunneling machine 4 moves forward by taking a reaction force to the inner formwork 5.

On the other hand, the poured concrete 7 is prevented from flowing away from the end side by a press ring, which will be described later.

The poured concrete 7 is pressurized by a press jack 6 via a press ring, and after the press ring is removed, the concrete is continued to be pressurized by a pressure holding ring 1.

<Port> Pressure retaining ring (Fig. 1) The pressure retaining ring 1 is an annular disk.

This pressure holding ring 1 is a prefabricated ring whose purpose is to work together with tie rods 2 to continue pressurizing the concrete and leet 7, and then to be used as is = 3 - to reinforce the concrete 7 of the tunnel. It is a member.

A plurality of holes are formed in the plate surface of the pressure retaining ring 1 for the tie rods 2 to pass through.

In order to improve the maneuverability of the shield tunneling machine 4, the plate width of the pressure retaining ring 1 is set to be smaller than the concrete lining thickness.

When the plate width of the pressure holding ring 1 is made smaller, the amount of gap between the tail plate 41 of the shield excavator 4 and the inner formwork 5 becomes larger, and fresh concrete is expected to flow out.

On the other hand, if the plate width of the pressure holding ring 1 is increased, it is expected that the maneuverability of the shield tunneling machine during direction correction, curve construction, etc. will deteriorate.

Therefore, the present invention first reduces the plate width of the pressure holding ring 1 to avoid contact with each surface of the tail plate 41 and the inner formwork 5, thereby ensuring maneuverability of the shield tunneling machine 4.

Then, the outflow of fresh concrete is controlled by the press ring described below.

<C> Press Ring (FIGS. 1 to 3) The press ring is composed of an annular box 3 and an annular end plate 8.

(1) Annular box The annular box 3 is a container in the shape of a long hollow prismatic cylinder bent into an annular shape.

As shown in FIG. 2, this annular box 3 is constructed so that the side surface on the face side can be separated.

The face-side side surface of the annular box 3 is configured to be detachable, for example, with bolts 32 or the like.

Furthermore, as shown in FIG. 3, the annular box 3 is configured to be divisible in the circumferential direction.

The divided annular boxes 3 can be connected and disconnected using bolts or the like.

Then, this annular box 3 is slidably mounted on the outer side of the most advanced thrust transmission formwork 51 on the face side of the inner formwork 5.

Further, insertion holes 33 for a large number of tie rods 2 are opened on the front and rear surfaces of the annular box 3, and work holes 34 for performing tie rod joining work are opened on the body side of the annular box 3.

Furthermore, a center hole jack is attached as a press jack 6 to the surface of the annular box 3 on the machine body side.

Further, a slit 31 is provided on the outer peripheral surface of the annular box 3 over the entire circumference.

(2) Annular end plate The annular end plate 8 is positioned within the slit 31 of the annular box 3.

This annular end plate 8 is not fixed to the annular box 3, but is positioned so as to be freely slidable in the circumferential direction inside.

The outer diameter of this annular end plate 8 is approximately equal to the inner diameter of the tail plate 41.

(2) Operation of the annular end plate The annular end plate 8 is slidably housed in the annular box 3.

And the annular box 3 is the thrust transmission formwork 5 at the end of the inner formwork 5.
It is installed on top of 1.

On the other hand, the inner formwork 5 maintains an accurate center line, and it is inevitable that the shield excavator 4 moves up and down, left and right, and deviates from the center line during excavation.

However, the outer periphery of the annular end plate 8 of the present invention is
is in contact with the inside of the tail plate 41 of.

Therefore, the annular end plate 8 moves freely within the annular box 3 and always functions as an end plate to prevent concrete from flowing out.

Effect of the present invention> Next, the tunnel construction method will be explained.

(a) Extension of tie rod Figure 4 shows the end of the concrete 7 constructed in the previous step.

A pressure retaining ring 1 and a tie rod 2 are exposed at the end of the concrete 7, and a fixing device 21 is attached to the end of each tie rod 2.

In order to pour new concrete onto this concrete 7, first, a separate tie rod 2 is connected by screwing the connector 22 onto the tie rod 2 protruding from the existing concrete 7.

(b) Assembling rings (Fig. 5) Next, the divided pressure holding ring 1 is carried into the tunnel.

In the tail plate 41 of the shield tunneling machine 4, the thrust transmission form 51 is separated from the inner form 5 and moved toward the machine body by one span.

Therefore, the pressure retaining ring 1 is temporarily fixed to the side surface of the annular box 3 positioned above the thrust transmission formwork 51 and assembled.

When assembling the pressure retaining ring 1, as shown in FIG.
Penetrate the inside.

(C) Assembling the formwork (FIG. 6) Next, the inner formwork 5 is assembled inside the tail plate 41.

(d) Press-fitting of concrete (Fig. 7) The gable side is closed by the annular end plate 8 and the annular box 3,
A shielded space surrounded by the inside of the inner formwork 5 and the tail plate 41 is formed.

Concrete 7 is injected into the entire area within this shielded space from a concrete injection pipe connected to the inner formwork 5.

(E) Pressurizing Concrete (Figure 8) Next, the press jacks 6 are operated all at once to pull each tie rod 2, and the concrete 7, which has not yet hardened, is pressurized.

Since the annular end plate 8 is in contact with the tail plate 41 while the concrete 7 is pressurized, outflow of the concrete 7 from the end side is restricted.

(f) Excavation of the shield (FIG. 9) The shield excavator 4 is advanced while extending the excavation jack 42 provided on the shield excavator 4 side to obtain a reaction force on the inner formwork 5.

Then, at the same time as the shield tunneling machine 4 moves forward, the tail plate 41 also moves toward the face side.

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

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

(g) Fixation of the pressure holding ring After the excess water in the concrete 7 is drained after completion of the shield propulsion, the fixing tool 21 is tightened using the working hole of the annular box 3, and the pressure holding ring 1 is fixed.

As the fixing device 21, a screw-in type, a model, or a clip type that can be attached from the side of the tie rod 2 to the tie rod 2 having recesses arranged around its outer periphery can be adopted.

[Dividing the annular box] As mentioned above, when assembling the pressure retaining ring 1,
When temporarily fixing the pressure retaining ring 1 to the side of the annular box 3 with bolts, etc., or when each tie rod 2 is attached to the annular box 3.
When penetrating the inside of the pressure holding ring 1 or when fixing the pressure retaining ring 1 with the fixing tool 21 after shield propulsion is completed, detailed work is performed and the work becomes complicated.

However, the annular box 3 of the present invention is constructed such that its face-side side surface is separable.

Therefore, after separating the side face on the face side, a wide open part is formed.

Therefore, even when performing detailed work as described above, the hand or tool can be inserted through the wide opening and the work can be performed easily.

Further, the annular box 3 is configured to be divisible in the circumferential direction.

Therefore, it is possible to easily install or remove the concrete 7 on the gable side.

Furthermore, since it can be divided into parts during transportation, it can be easily transported.

(H) Removal of the annular box After the work of fixing the pressure retaining ring 1 is completed, the annular box 3 is removed together with the thrust transmission formwork 51.

The above process is repeated and concrete is successively poured to construct the specified tunnel.

(S) When passing through a curve or correcting the direction When the tunnel passes through a curve or the direction of excavation is to be corrected, the annular end plate 8 moves freely according to the amount of relative movement between the shield tunneling machine 4 and the inner formwork 5. Therefore, the distance between the annular box 3 and the tail plate 41 is always compensated for.

Therefore, the shield tunneling machine 4 is allowed to move freely, allowing smooth construction.

<Other Embodiments> In the above embodiment, the annular end plate 8 is slidably positioned on the outer peripheral surface side of the annular box 3. However, as other embodiments, the above embodiment may be used even in the opposite case. A similar effect can be obtained.

That is, the outer diameter of the annular box 3 is formed to be approximately equal to the inner diameter of the tail plate 41, and the annular end plate 8 is formed to have a slightly smaller diameter than the inner diameter of the tail plate 41.

Then, a slit is provided on the inner peripheral surface side of the annular box 3,
The structure is such that the annular end plate 8 is positioned within the slit so as to be slidable in the circumferential direction.

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

(a) The position of the inner formwork is always on the exact center line.

On the other hand, shield tunneling machines cannot always dig accurately.

Therefore, the distance between the two is constantly changing, and as a result, when concrete is poured, there is a possibility that the concrete will flow out from the gable side.

However, since the annular end plate of the present invention contacts the inside of the tail plate and can freely move in the circumferential direction within the annular box, the end side can always be completely closed.

(b) Since the annular end plate that does not create a gap between the formwork and the shield excavator is slidably positioned, the shield excavator can smoothly perform construction on curves with a small radius.

(c) In the present invention, when assembling the pressure retaining ring, the pressure retaining ring is temporarily fixed to the side of the annular box with bolts, etc., each tie rod is passed through the inside of the annular box, or the seal propulsion is completed. Later, when fixing the pressure retaining ring using a fixing tool, detailed work is performed and the work becomes complicated.

However, the annular box of the present invention has a structure in which the side surface on the face side is separable.

Therefore, after separating the side face on the face side, a wide open part is formed.

Therefore, even when performing detailed work as described above, the hand or tool can be inserted through the wide opening and the work can be performed easily.

(d) The annular box of the present invention is configured to be divisible in the circumferential direction.

Therefore, it is possible to easily install or remove the concrete on the gable side.

Furthermore, since it can be divided into parts during transportation, it can be easily transported.

(e) Bury reinforcing bars and tie rods in the concrete.

At this time, with the apparatus of the present invention, construction can be carried out while maintaining a constant amount of cover from the inside of the concrete to the reinforcing bars.

[Brief explanation of the drawing]

Figure 1: Explanation of one embodiment of the present invention Figures 2 and 3 = Explanatory diagram showing the divided state of the annular box Fourth
~Figure 9: Explanatory diagram of construction order

Claims (1)

[Claims] (1) A shield excavator in which an annular formwork is positioned at the inside rear of the shield excavator, the formwork takes a reaction force to advance the excavator, and at the same time concrete is placed in place between the formwork and the ground. , an annular pressure-retaining ring that maintains the compression of the concrete by absorbing the reaction force against reinforcement placed in the cast-in-place concrete; It consists of a hollow annular box with a slit around the circumference and a separable face-side side surface, and an annular end plate that is slidably attached in the circumferential direction within the slit of the annular box. A cast-in-place shield tunneling machine, characterized in that the diameter or outer diameter of the end plate is approximately equal to the inner diameter of the shield tunneling machine.