JPH0330475Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a tail seal device for preventing underground water and backfill material from flowing into the interior of a shield machine.

(Conventional structure and its problems) When constructing a tunnel while excavating the ground with a shield machine, segments are assembled into a ring shape within the outer cylindrical tail plate of the shield machine to form the tunnel lining. The shield machine moves forward using this lining as a reaction force.

In this case, a certain distance (tail clearance) is provided between the outer circumference of the segment ring and the inner circumference of the tail plate, and this tail clearance is used to assemble the segments and control the direction of the shield machine. Since underground water and backfill materials flow into the shield machine and enter the shield machine, a tail seal device is installed in the tail clearance to prevent this.

Conventionally, as shown in Figs. 6 to 8, such a tail seal device has a plate-shaped or tube-shaped seal body c whose tip is brought into close contact with the outer periphery of the segment and is integrally attached to a mounting part b that is attached to the tail plate a of the shield machine. The one provided is used,
Side pressure such as underground water pressure is counteracted by the friction of the segments and the rigidity of the seal body c.

However, the ring in which the segments are assembled is not necessarily concentric with the tail plate a, and is often offset to one side. Due to this deviation, the tail clearance is wide on one side and narrow on the other side, and with a wide tail clearance, the lateral pressure due to water pressure acts greatly, and the seal body c may turn over toward the sealing machine, especially under high water pressure. Also, in the case of narrow tail clearance,
Seal body c is crushed by the tail plate and segment, damaging the sealing device, causing problems such as groundwater flowing into the sealing machine, making it impossible to perform backfill injection sufficiently, and eventually causing ground subsidence. Ta.

(Purpose of the invention) This invention was made in view of the above problems.
To provide a tail seal device for a shield machine that eliminates the occurrence of curling and exhibits a reliable water-stopping effect.

(Structure of the Invention) In order to achieve the above object, the tail seal device of the present invention has a shield device at both front and rear ends of an annular tail seal body having a substantially V-shaped cross section and a height substantially equal to the maximum tail clearance. A mounting piece to which the tail plate is fixed is provided, and a tongue piece is integrally provided around the center tip of the inner circumferential surface of the tail seal body, which is inclined rearward and diagonally inward, and furthermore, the tail seal body has an approximately V-shape. A pressurized fluid chamber is provided between the outer peripheral surface of the shape and the tail plate, and by supplying pressurized fluid to this pressurized fluid chamber and pressurizing the inside of the pressurized fluid chamber, the tongue piece is firmly pressed against the segment. In addition, the tongue piece is positively pressed against the segment by underground water pressure or the like.

(Explanation of Embodiments) The embodiments of the present invention will be explained with reference to the drawings.
is an annular tail seal body having a substantially V-shaped cross section, and is made of an elastic material such as synthetic rubber or an elastic resin material, and has a front end at the center tip of the inner circumferential surface, which is the connecting part between the front circumferential wall 1a and the rear circumferential wall 1b. A ring-shaped tongue piece 2 that is an extension of the peripheral wall 1a and is tilted toward the rear and diagonally inward.
are all surrounded by one. Furthermore, circular flange-shaped mounting pieces 3 and 4 are integrally provided at the outer peripheral ends of the front peripheral wall 1a and the rear peripheral wall 1b, respectively.

The mounting pieces 3 and 4 of the tail seal main body 1 are brought into close contact with the inner circumferential surface of a cylindrical tail plate 5 of the outer shell of the shield machine, and are hermetically fixed to the tail plate 5 with bolts 7 via a presser metal fitting 6.

Reference numeral 8 denotes a pressurized fluid chamber formed in a space between the V-shaped outer peripheral surface of the tail seal body 1 and the inner peripheral surface of the tail plate 5.

As shown in FIG. 2, this pressurized fluid chamber 8 integrally connects the front and rear mounting pieces 3 and 4 with an annular joint plate part 9, and connects this joint plate part 9 with the front and rear peripheral walls 1a,
It may be formed by a space surrounded by 1b.

Reference numerals 10 and 11 are pressurized fluid supply holes and discharge holes that are bored in the tail plate 5 in the front-rear direction and communicate with the pressurized fluid chamber 8.

Reference numeral 12 denotes a stopper which has a thickness approximately twice that of the tail seal body 1 and is made of the same material as the tail seal body 1, and is located close to the front end of the front mounting piece 3 of the tail seal body 1. It is fixed to the inner circumferential surface of the plate 5 to prevent pressure loss in the tail plate body 1 when the segments 12 are shifted to one side.

Reference numeral 13 designates a tensile-resistant material such as a steel cord embedded in the tail seal body 1 from the mounting pieces 3 and 4 to the tongue piece 2.

Note that the tail seal body 1 serves as the pressurized fluid chamber 8.
A rubber tube 14 may be inserted into the chamber part on the V-shaped outer circumferential surface of the rubber tube 14, and the fluid supply hole 10 and the discharge hole 11 may be communicated with the rubber tube 14. A wear-resistant material 15 such as ceramic may be welded to the surface. Furthermore, when filling air etc. into the pressurized fluid chamber 8 or the rubber tube 14, the discharge hole 1
There is no need to provide 1.

(Function) The function when the tail seal device configured as described above is provided in the tail clearance 17 between the tail plate 5 and the segment 16 will be described.

First, when a fluid such as high-pressure air, water, oil, etc. is introduced into the pressurized fluid chamber 8, the segment 16 sets the distance at which the center tip of the inner circumferential surface of the tail seal body 1 is separated from the tail plate 5 to the stopper 12. The clearance should be approximately equal to the maximum clearance when it is shifted to one side until it makes contact.

Note that even if the pressurized fluid chamber 8 does not contain pressurized fluid, the main body 1 is formed to have a V-shaped cross section as described above, and its height is formed to be approximately equal to the maximum tail clearance.

When the segment 16 is assembled in the tail plate 5 of the shield machine, the tongue piece 2 of the tail seal body 1
Since the ring diameter at the tip of the tongue piece 2 is smaller than the outer diameter of the segment 16, a tensile force is applied to the tongue piece 2, so that the tongue piece 2 is bent toward the rear of the shield and tightly attached to the segment side.

Thereafter, when a pressurized fluid, for example water 18, is injected into the pressurized fluid chamber 8 from the front of the shield machine through the supply hole 10 by an appropriate means, the air in the chamber is discharged from the exhaust hole 11 and no air is left in the chamber. filled with water,
If the discharge hole 11 side is closed by an appropriate means, the water is pressurized and the inside of the tail seal main body 1 is maintained at a predetermined pressure, the compression resistance is increased, and the shape is maintained.

In this state, when a fluid substance such as high-pressure ground water or backfill injection acts on the tail seal body 1 from the rear of the sealing machine, the pressure of the fluid substance will be applied to the same wall at the rear of the tail seal body 1, as shown in Figure 3. It acts in the direction of pressing 1b forward and in the direction of pressing the tongue piece 2 against the segment 16.

At this time, the rear peripheral wall 1b of the tail seal main body 1 on the tail plate side responds to the force pushing forward.
is exerted on the tension side by the rear fixing piece 4, and on the segment side, a frictional force is generated between the tongue piece 2 and the outer periphery of the segment 16 due to the elastic force of the tongue piece 2 and the pressing force due to underground water pressure, etc. acts and counters.

The above condition is tail plate 5 and segment 1
6 is stationary, but when the tail plate 5 moves forward together with the shield machine, the friction between the tongue piece 2 of the tail seal body 1 and the segment 16 creates resistance that pulls the tail seal body 1 toward the rear of the shield machine. However, in response to this, the front peripheral wall 1 is fixed by the fixed end of the front mounting piece 3 of the tail seal body 1.
a acts in tension and can move forward.

In this way, the tongue piece 2 of the tail seal main body 1 is pressed against the outer periphery of the segment by groundwater pressure, thereby preventing groundwater etc. from entering the shield machine, and also preventing the tail seal main body 1 from deforming toward the front of the shield machine. It can be prevented.

Moreover, even if the groundwater pressure fluctuates, the tail seal body 1 can be reliably pressed against the segment 16 by adjusting the pressure of the pressurized fluid accordingly.

Note that, as shown in FIG. 5, if reinforcing ribs 19 and 20 are integrally provided on the tongue piece 2 and the peripheral wall of the pressurized fluid chamber 8, even stronger prevention of curling and a crimping effect can be achieved.

(Effects of the invention) As described above, according to the tail seal device of the present invention, the annular tail seal body 1 is formed to have a substantially V-shaped cross section and a height substantially equal to the maximum tail clearance, and the outer circumferential surface and Since the pressurized fluid chamber 8 is provided between the tail plates, the tail seal main body 1 is sealed by filling the pressurized fluid chamber 8 with pressurized fluid.
can be reliably crimped to the outer periphery of the segment to eliminate tail clearance, and furthermore, a tongue piece 2 that faces rearward and is inclined diagonally inward is integrally provided at the central tip of the inner peripheral surface of the tail seal body 1. As mentioned above, since the central tip of the inner circumferential surface of the tail seal main body 1 comes into pressure contact with the outer periphery of the segment, the tongue piece 2 protruding from this tip can be pushed over almost the entire length of the segment. The tongue piece 2 can be pressed against the outer circumferential surface of the segment, and furthermore, the tongue piece 2 can be pressed against the outer circumferential surface of the segment by the underground water pressure existing between the outer circumferential surface of the tongue piece 2 and the rear circumferential wall surface of the tail seal main body 1. The tail seal main body 1 is prevented from being deformed in the forward direction of the shield machine due to the frictional force generated between the two when pressed by the seal, thereby eliminating the occurrence of curling of the tail seal and ensuring reliable water-stopping action. be.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, and FIGS. 1 and 2 are enlarged longitudinal sectional side views of Example 1 and 2, FIGS. 3 and 4 are longitudinal sectional side views showing the water-stopped state, and FIG. The figure is an enlarged longitudinal side view of Example 3, and FIGS. 6 to 8 are cross-sectional views of conventional tail seals. 1... Tail seal body, 2... Tongue piece, 3, 4
... Mounting piece, 8... Pressurized fluid chamber.

Claims (1)

[Scope of utility model registration request] Attachment pieces 3 and 4 that are fixed to the tail plate of the shield machine are provided at both front and rear ends of the annular tail seal body 1, which has a substantially V-shaped cross section and whose height is approximately equal to the maximum tail clearance. A tongue piece 2 slanting rearward and diagonally inward is provided integrally around the center tip of the inner circumferential surface, and a pressurized fluid chamber 8 is further provided between the approximately V-shaped outer circumferential surface of the tail seal body 1 and the tail plate. A tail seal device for a shield machine.