JPH02197700A - Leak-preventive device for shield tail section - Google Patents

Abstract

PURPOSE:To prevent the intrusion of groundwater from the rear end section of a tail plate by installing a nozzle to an inner circumferential surface near an end section on the side reverse to the facing of the tail plate of a shielding machine. CONSTITUTION:A required number of nozzles 4 are buried and mounted so as not to project from the inner circumferential surface of a tail plate 11 of a section, where the inner circumferential surface of an end section on the side reverse to the facing of the tail plate 11 of a shielding machine and a lining 16 are superposed and brought into contact, to the inner circumferential surface of the tail plate 11, and connected to the end section of an injection pipe 3 buried into the tail plate 11. When the fixed curing time passes and the initial strength of the lining 16 is manifested, an injection pump 2 is operated, the cut-off material 5 of hydrolytic reac tion type polyurethane, etc., is force-fed into the injection pipe 3 on the side, where a clearance S is shaped, and the cut-off material 5 is injected to all sections of the clearance S while maintaining injection pressure higher than peripheral groundwater pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a water leakage prevention device for a shield tail portion of a shield machine used in a cast-in-place lining method.

<Conventional technology> In general, the cast-in-place lining construction method involves assembling reinforcing bars inside the tail plate of a shielding machine, then assembling formwork inside, and pouring concrete between the formwork and the tail plate. This is a construction method in which the concrete is pressed at the same time as the concrete is pushed forward, and the concrete lining is then cured at the end.

By the way, when using the cast-in-place lining method, work is carried out in the ground where groundwater exists.

There is a risk that surrounding groundwater may enter the shield machine from the end opposite to the face of the tail plate of the shield machine, causing water leakage.

Therefore, conventionally, water leakage from the rear end of the tail plate of a shielding machine has been prevented only by the adhesive force of the portion where the inner circumferential surface of the tail plate and the lining overlap.

<Problems to be Solved by the Invention> Conventionally, water leakage was prevented only by the adhesive force between the tail plate and the lining.

However, when underground water pressure is high or when a gap is created between the tail plate and the lining due to the shaking of the shield machine, it is difficult to prevent water leakage only by the adhesive force between the tail plate and the lining. The reality is that work is carried out while using a pump to drain water that has entered the shield machine.

For example, when moving to the next cycle after completing one cycle using the above construction method, the reinforcing bars are assembled first, but at this time, the propulsion jacks that take the reaction force against the inner formwork are partially retracted, and the reinforcing bars are brought in. , it is necessary to secure space for assembly.

However, when the propulsion jack is partially retracted in this way, the shield machine becomes eccentric due to the earth water pressure received from the face, and a gap is created between the tail plate and the lining in its initial hardened state.

Therefore, if water pressure is applied from the ground around the shield machine, water will enter through the gaps and cause water leakage.

<Object of the present invention> The present invention has been made to solve the above-mentioned problems, and is a method for preventing water leakage from the shield tail portion, which can reliably prevent the infiltration of groundwater from the rear end of the tail plate. The purpose is to provide equipment.

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

<A> Structure of the entire device (Fig. 1) The shielding machine 1 shown in Fig. 1 is constructed by assembling reinforcing bars inside the tail plate 11, further assembling the inner formwork 12, and then forming a structure between the inner formwork 12 and the tail plate 11. This is a known device that places concrete, then propels the shielding machine 1 with a propulsion jack 13, presses the concrete with a press jack 15 through a press ring 14, and finally cures and constructs a concrete lining 16. be.

It has a structure in which an injection pump 2, an injection pipe 3, and a nozzle 4 are connected and attached to the holder, and the water stop material 5 can be injected from the nozzle 4.

<Port> Injection Pump (Fig. 1.2) The injection pump 2 is capable of pumping the fluid water stop material 5 at an arbitrary pressure in order to counter ground water pressure and concrete placement pressure.

The necessary number of injection pumps 2 are attached to the shield machine 1, taking into consideration the size of the shield machine 1.

<C> Injection pipe (Fig. 1.2) The injection pipe 3 has one end connected to the injection pump 2, and the other end connected to the nozzle 4 provided near the end opposite to the face on the inner peripheral surface of the tail plate 11. It is a connected tube body.

As shown in FIG. 2, this injection pipe 3 is preferably partially buried in the tail plate 11 and arranged such that the end of the buried part reaches the nozzle 4.

Further, a check valve 31 is provided near the injection pump 2 midway through the injection pipe 3 to prevent the pumped water stop material 5 from flowing backward.

Furthermore, it is preferable that the portion of the injection tube 3 exposed inside the shield machine 1 be one or several, as small as possible, and the portion buried in the tail plate 11 branched to each nozzle 4 and connected.

In the case of branching, a switching device is provided at the branch point so that the water stop material 5 can be fed under pressure only to an arbitrary injection pipe 3.

Note that the injection pipe 3 may independently connect the injection pump 2 and the nozzle 4.

If the injection pipe 3 is buried as described above, the tail plate 1
It does not protrude from the inner circumferential surface of 1 and does not interfere with other work.

<2> Nozzle (Fig. 2.3) The nozzle 4, as shown in Fig. 3, for example, has a cylindrical body 41 with an open center, and is installed in the opening and is always biased to close by a spring or the like. It consists of a valve 42.

This nozzle 4 is located at a portion of the tail plate 11 where the inner peripheral surface of the tail plate 11 overlaps and contacts the lining 16 when the shield machine 1 completes digging as shown in FIG.
Provide the required number on the inner peripheral surface.

Further, the nozzle 4 is embedded and attached within the tail plate 11 so as not to protrude from the inner circumferential surface of the tail plate 11, and is connected to the end of the injection tube 3 embedded within the tail plate 11.

When embedding it, it is preferable to carve a threaded groove on the outer circumferential surface of the cylindrical body 41 and screw it into the tail plate ll.

In the nozzle 4 configured in this way, when a pressure higher than the surrounding groundwater pressure is applied from the injection pipe 3fR to the valve 42, the valve 4
2 is now open.

The opening pressure of the nozzle 4 should be set by checking the groundwater pressure in advance (.

Note that other valve mechanisms such as a known electromagnetic valve or electric valve may be used for the nozzle 4.

<E> Water-stopping material The water-stopping material 5 is water-resistant and fluid enough to be pumped through the injection pipe 3 by the injection pump 2.

For example, water-reactive polyurethane or the like can be used.

<Method of Injecting Waterstop Material> Next, a method of injection of waterstop material using the apparatus of the present invention will be described.

<A> Occurrence of gaps Figure 1 shows that the shield machine 1 has finished digging and the lining 1
6 is in a state of curing.

After a predetermined curing time has elapsed, the press ring 14 is retracted to the face side, and reinforcing bars are assembled for the next cycle.

At this time, a part of the propulsion jack 13 is retracted in order to assemble the reinforcing bars.

Then, due to the water pressure that the shield machine 1 receives from the face, the shield machine 1 is eccentric to the side where the propulsion jack 13 is retracted, and the second. A gap S as shown in FIG. 3 is created.

<Exposure> Injecting the water stop material When the predetermined curing time has passed and the initial strength of the lining 16 has been developed, the injection pump 2 is operated to inject the water stop material 5 into the injection pipe 3 where the gap S has occurred. to pump.

At this time, the water stop material 5 is pumped at an injection pressure such that the pressure inside the injection pipe 3 is higher than the surrounding groundwater pressure.

Then, the valve 42 of the nozzle 4 is pushed open, and the water stop material 5 is injected into the gap S.

Then, while maintaining the injection pressure of the water stop material 5 at a pressure higher than the groundwater pressure, the water stop material 5 is injected into every corner of the gap S,
After the injection is completed, the operation of the injection pump 2 is stopped.

<Action of the present invention> Next, the operation of the present invention will be explained.

The water stop material 5 is injected into every corner of the gap S while maintaining a pressure higher than the groundwater pressure.

Therefore, in the gap S, a layer of water stop material S as shown in FIG. 4 is formed.

This layer of water stop material 5 maintains a pressure higher than the water pressure in the ground around shield machine 1.

Therefore, it is possible to completely block off the water supply in the gap S into which surrounding groundwater infiltrates.

Therefore, it is possible to prevent groundwater from entering the shield machine 1 through the gap S.

Effects of the Present Invention> Since the present invention has been described above, the following effects can be expected.

<B> In the case of a shield machine used in the conventional cast-in-place lining construction method, when the propulsion jack is partially retracted to assemble reinforcing bars, for example, water can enter through the gap between the tail plate and the lining, causing water leakage. There was a risk.

In contrast, the shielding machine of the present invention has a structure in which the gap created between the tail plate and the lining can be filled by injecting a water stop material at a pressure higher than the groundwater pressure around the shielding machine.

Therefore, there is no risk of water entering through the gap created between the tail plate and the lining as in the conventional case, and water leakage can be reliably prevented.

<Exposure> The shielding machine of the present invention can reliably prevent water leakage from the tail portion, so construction can always be carried out in a dry state.

Therefore, a high quality lining can be constructed.

(c) The cast-in-place lining method can be applied even on ground with high groundwater pressure, expanding the scope of construction.

(2) Since a fluid water-stopping material is used, it can follow any shape change of the lining, making it possible to reliably prevent water leakage.

<E> Unlike tail seals, it does not wear out, so you can save time and effort in replacing it.

<F> Since a water stop material is injected between the inner circumferential surface of the tail plate and the lining, the lining is easily removable.

Figure 4: Explanatory diagram of water stop material injection state

[Brief explanation of the drawing]

Figure 1: An explanatory diagram of one embodiment of the device of the present invention. Figure 2: An enlarged view of the device of the present invention. Figure 3: An enlarged diagram of the nozzle portion.

Claims (1)

[Claims] (1) A device for preventing water leakage from the tail portion of a shielding machine used in the cast-in-place lining method, characterized in that a nozzle is provided on the inner peripheral surface near the end opposite to the face of the tail plate of the shielding machine. , Water leakage prevention device in the shield tail section.