JPS5918518B2 - Backfill injection method for lining segments in shield construction - Google Patents

Description

[Detailed Description of the Invention] In tunnel excavation work using the shield method, the present invention injects backfill material into the tail void from the tail part of the shield machine, thereby rationally and without inducing loosening of the ground. This invention relates to a backfill injection method for lining segments that can be constructed efficiently.

In tunnels constructed using the shield method, the tunnel is excavated along the outer shell of the shield machine, but the lining segments (hereinafter simply referred to as segments) are assembled at the tail part of the shield machine. Therefore, a gap is left between the excavated ground and the segment outer diameter, which is the sum of the thickness of the shield machine outer shell, the shield machine tail inner diameter, and the segment clearance. It is called a tail void.

This tail void almost coincides with the center line of the segment and the shield machine when the segment is assembled inside the seal machine, but once the shield machine is propelled, the tail void is assembled as shown in Figure 3. Segment) A descends into contact with the bottom of the excavated tunnel B under its own weight, and follows the center line of the intended tunnel.

The gap between the top of segment A) assembled for this purpose and the ground will be doubled, and if a large gap is left unattended, the ground will inevitably loosen and the ground will not sink. Of course, this will also cause uneven pressure in the segment.

Therefore, in order to solve this problem and further obtain the waterproof effect of the segment lining, it is necessary to promptly inject a backfilling material into the tail void to eliminate the void.

Conventional backfill injection work for tail voids uses grout holes provided in segments to inject backfill material, and in this case, the minimum length that can be injected after the shield machine excavates. is the dimension between grout holes, ie, one ring segment.

The excavation propulsion speed of the shield machine is usually about 30 minutes to 1 hour per ring segment.

On the other hand, in soft ground, the ground loosens in 10 to 15 minutes, causing subsidence.

In this case, it is necessary to advance the excavation and inject backfill as quickly as possible to prevent the ground from loosening.

However, conventionally, backfilling is injected from the grout hole of the segment, so even if the situation of tail voids can be predicted, there is no way to immediately respond to it, and as a result, conventional methods have been resorted to while still having various problems. There is.

The present invention solves these problems and promptly injects backfilling material into the tail void in response to the excavation of the shield machine, allowing lining work to be carried out very rationally and efficiently even under adverse conditions. can be carried out effectively, and
The aim is to create a backfill injection method that adjusts the setting conditions of the backfill injection material according to the excavation conditions and can provide a lining that is completely waste-free and leak-free.

In addition, the present invention provides that each time the shield machine excavates from the tail part of the shield machine excavating into the tail void, from the tip injection port of the backfilling hole that opens toward the excavation gap provided inside the machine tail part. The purpose is to inject the backfilling material, and at this time, the setting time of the backfilling material is arbitrarily set according to the situation at the shield tail portion, so that the backfilling can be performed most effectively and efficiently.

Furthermore, in the present invention, when injecting backfilling material into the tail void from the tail portion of the shield machine, when the required amount of filling is completed, the tip injection port of the backfilling hole is immediately closed until the next injection. , that is, a reciprocating body 'ff that doubles as a plug and a cleaning body is installed in the injection part to prevent the injection liquid material from condensing in the injection hole.
However, the objective was to be achieved by providing a means for smoothly performing intermittent continuous injection operations.

In the present invention, a pressure gauge, a flow meter, etc. are attached to a part of the backfilling material injection means in order to check the filling condition when backfilling is performed on the tail section or tail void of the shield machine. Then, the inflow dynamics of the backfilling material are observed and detected using these instruments, and the completion of filling is confirmed.Then, the tip of the injection hole is closed until the next filling operation, and the backfilling material is backfilled into the pipe. This prevents the material from remaining and causing condensation.

In order to achieve such an object, the present invention uses a shield machine having one or more injection parts for backfill material in parallel to the axial direction of the shield tail part, and injects the backfill material into the shield tail part. A mortar mixer supply device installed outside the mine, etc., which mixes clay sand or a similar material with cement, a foaming agent, and water as a filler, and a coagulant mainly composed of a substance such as water glass. A regulating device that can selectively supply the coagulant by switching the discharge amount of the coagulant in multiple stages, which is placed outside or inside the mine, is used to pump the coagulant to the shield tail section through individual supply pipes.
Backfilling material and an appropriate amount of coagulant are supplied to the injection part of the tail of the shield machine via a mixing device, and the coagulation rate is controlled by setting the coagulant supply amount to a mixing ratio according to the conditions of the injection location. Inject the backfilling mixture from the injection part of the machine tail into the tail void part after the shield machine excavates, and once it is filled, close the tip injection port of the injection part from the inside with the plug operating body attached to the injection part. This operation is repeated one after another to inject the backfilling material into the voids created after excavation and allow the filling to solidify.

Below, a specific example of the backfill injection method of the present invention will be described in detail with reference to drawings. In Fig. 1, 1 is a shaft, 2 is an excavation method tunnel, 3 is a shield machine, 4 is a face, and 5 is a moving A workbench, 6 is a lining made of assembled steel segments, 10 is a mortar plant for backfilling installed outside the mine, and a setting adjustment unit 12 for supplying a coagulant is placed on the appropriately framed workbench 11 to perform this work. A mortar mixer 13, a hopper 14, and a mortar pressure pump 15 are provided in association with each other in the vicinity of the stand 11, and the mortar pressure pump 15 and a condensation adjustment unit 12 are provided.
A mortar pressure feed pipe 16 and a coagulant pressure feed pipe 1T are installed from the tail section of the shield machine 3 to the tail section of the shield machine 3 so as not to interfere with other operations.
The tips of both pipes are flexible pipes 16' of appropriate length.
, 17' to a mixing device 20, and the outlet side of the mixing device 20 is connected to an injection mechanism (described later) provided in the tail portion of the shield machine 3.

As illustrated in FIG. 2, the backfilling insertion mechanism 30 provided at the tail portion of the shield machine 3 includes an intermediate plate 32 inside the tail portion of the outer shell 31 of the shield machine.
, an inner plate 33 is integrally provided, and a plurality of backfilling holes 34 are formed in at least one location on the upper part of the machine in the intermediate plate 32 section, or at appropriate locations around the entire circumference, parallel to the axis of the machine. The injection hole 34
The tip opens toward the tail void side, and the fluid pressure cylinder 35 is attached to the rear end, and the piston 35' is inserted into the injection hole 34, and the backfilling mixture is injected into the position just before the most retracted position of the piston 35'. A pipe connection port 36 is provided, and this connection port 36
A pressure feed hose 23 is connected to the outlet 21 of the mixing device 20 via an on-off valve 22, and a pressure gauge 24 is attached to the discharge side of the mixing device 20 to check the injection and discharge pressure of the mixed material. put.

A flow meter 18 is attached to the tip of the mortar pressure feeding pipe 15 so that the amount of mortar supplied can be checked.

The pressure feed hose 23 is made detachable from the connection port 36, and a plurality of holes 34 with backfilling are provided.
When a branch pipe is attached to the discharge part and the outlet of this branch pipe is connected to each injection hole connection port 36 with a pressure feed hose 23 via an on-off valve, and a large number of injection holes are arranged (when the shield machine is large). For this purpose, a plurality of mixers are provided, and the required number of mixers are branched from each mixer and connected to each injection hole.

Further, a sample outlet is provided on the output side of the mixing device 2 (E7) so that the mixing ratio of mortar and coagulant, that is, the setting time can be instantly set by switching the cock 25.

Valves 19 and 19' are interposed in each supply pipe to the mixer 20 so that the supply of mortar and coagulant can be controlled by these valves 19 and 19'.

Furthermore, a communication means is arranged between the shield tail part and the backfill material adjustment plant 10 position so that workers at both positions can communicate with each other, and the coagulation adjustment unit 12 includes a coagulant tank, a plunger pump, and A plurality of valves with different opening flow rates are arranged in parallel on the discharge side of the pump and branched and connected,
The outlet side of each valve is connected to a common outlet pipe and connected to piping 17, and the discharge side valve is selected depending on the situation at the shield part to send out at the appropriate flow rate. .

37 is a washing water discharge pipe. Using such equipment,
In 10 parts of the plant outside the mine, clay sand or similar fine aggregate, Portland cement, foaming agent, and water are mixed and mixed in appropriate amounts to make mortar for backfilling. The coagulant is also force-fed from the adjustment unit 12 through the piping 17, mixed by the mixer 20tC, and passed from its outlet through the pressure-feeding hose 23 to the injection mechanism 30 attached to the shield machine 3. The backfilling mixture is press-fitted into the tail void C created by excavation through the opened backfilling inlet hole 34.

When injecting the backfill mixture into the void from the tail portion of the shielding machine, if the shielding machine has a plurality of injection mechanisms 30, ie, injection holes 34, the piston 35' must be advanced before injection. The piston 35' is positioned at the tip of the injection hole so that it acts as a plug, and depending on the injection situation, the necessary cylinder 35 is operated to move the piston back, opening the injection hole 34 and filling the void. Perform backfill injection.

Therefore, the unused injection hole is kept closed and no backflow occurs due to the backfilling pressure.

Next, the backfilling material is injected through the valve 1 on the side of the mortar pressure feed pipe 16.
9' is opened to feed the mortar first, and then the valve 19 on the IT side of the coagulant pressure feed pipe is opened for mixing, and the backfilling mixture with the desired mixing ratio is fed into the void. To stop the supply of the mixed material, first close the valve on the coagulant side, supply only mortar for an appropriate time, then stop the supply, and then move the piston 35' of the injection mechanism 30 to the cylinder 35. It is moved forward by the operation of , and the mortar hanging in the injection hole 34 is pushed out to the void side and sealed.

The status of this backfilling is determined by estimating the amount of filling in advance using a flow meter 18 installed in the mortar pressure feeding pipe 16, and by reading fluctuations in the normal pressure during supply using a pressure gauge 24 attached to the mixer 20. to detect the end of filling.

As mentioned above, when press-fitting the backfilling mixture into the void, 1
When feeding from multiple mixers through multiple injection holes, it is necessary to take care not to reduce the flow rate of the feed material in each pressure feed hose 23. Therefore, if it is difficult to synchronize each distribution pipe, at least one The hose is opened and supplied, and the operation order at that time is the same as described above, and in some cases, measures are taken to switch the appropriate amount from one place to the injection hole at the other position and inject. Good too.

Furthermore, if multiple mixers are used, each can be injected independently; in this case, filling time can be shortened by injecting simultaneously from the top and bottom of the tail of the shield machine. Can be done.

If backfilling is performed with a plurality of other injection parts arranged, even if any one of them breaks down, the filling operation can be carried out without any problem.

In this way, every time the shield machine excavates, if a void is formed in the tail part, the injection hole is immediately opened and the backfill mixture is injected, filling the tail void with the backfill material in a very short time. In addition, the backfill material can be set within the setting time depending on the situation, so if the segment assembly work in the shield tail part is carried out smoothly, the shield excavation work can be carried out without any problems, and the lining work can be completed. It is possible to achieve this without any doubt, and rationalization can be achieved.

Of course, by using clay sand, etc. as a backfilling material, the filling effect in voids during backfilling will be increased, and it will also penetrate into the joints of segments and solidify in a preset setting time, so there will be no leakage in the lining part. This can be reliably prevented and has an effective effect on subsequent work.

According to the construction method of the present invention as shown in the diagonal top, backfilling material is press-fitted from the tail part of the shield machine through the injection hole attached to the machine every time the machine makes one thrust movement between the tail part of the shield machine and the part that has already been filled by excavation. As a result, the lining segment can be backfilled without having to completely assemble one ring and then assemble the next ring. Therefore, it can be backfilled by following the thrust of the shield machine, and the ground that is created by excavation can be backfilled. This allows for safe tunnel excavation because it is possible to prevent the loosening of the lining in advance, and the back of the lining ring and the surface of the excavated ground can be kept tight and stable at all times without relying on the grout injection holes of the segments. This, combined with the appropriate setting of the condensation time, has made it possible to perform shield excavation effectively even in soft ground without fear of ground subsidence.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an embodiment of the backfill injection method used in the shield construction of the present invention, and Fig. 2 is a schematic diagram of a specific example showing the main parts of the backfill injection part of the shield machine used in the method of the present invention. , FIG. 3 is a diagram showing the relationship between the shield excavation tunnel and the lining segments. 2...i removed) tunnel, 3... shield machine, 6...
・Oto Esegment, 10...Mortar Plant, 12
... Coagulant supply adjustment unit, 16... Mortar pressure feeding pipe, 17... Coagulant pressure feeding pipe, 16', 17'.
...Flexible tube, 1B...Sulfur meter, 19, 19', 22...
・Opening/closing valve, 20...Mixing device, 23...Pressure hose, 24...Pressure gauge, 30...Injection mechanism, 34...-
- Injection hole, 35...Fluid pressure cylinder, 35'...Piston, 36...Injection hole connection port.

Claims (1)

[Claims] 1. Using a shield machine equipped with one or more backfilling material injection parts having injection holes opening toward the excavation gap inside the tail part, clay sand or clay sand is used as the backfilling material. A mortar supply device installed outside the mine, etc., and a filler made by kneading similar fine aggregate and cement with a foaming agent and water, and a coagulant such as water glass, and the amount of coagulant placed outside or inside the mine. A coagulant supply adjustment device that can selectively adjust the supply amount by switching the backfilling material in multiple stages is used to individually pressure feed it to the shield machine tail section, and the backfilling material and an appropriate amount of coagulant are fed through a mixing device to the shield machine. Set the coagulant supply amount to the mixing ratio according to the conditions of the injection point, adjust the coagulation speed, and inject the backfill mixture into the void immediately after the machine excavates from the injection part. The distal injection port of the injection hole is closed from the inside using a stopper operating body that is attached to the injection part and has a mechanism that can freely move forward and backward within the injection hole, and this operation is sequentially repeated to fill the void created after excavation. Backfill injection method for lining segments in shield construction. 2. Adopt a shield machine with multiple injection parts distributed in the tail section according to the diameter of the excavated tunnel, and reduce each supply pipe from the backfill filler and coagulant supply pipe to multiple mixing machines. Lining in shield construction according to claim 1, in which the backfilling material is simultaneously or selectively injected into the gap of the shield tail by connecting and piping from each mixer to one or more injection holes. Segment backfill injection method. 3 The setting time of the backfilling material is controlled by a multi-stage switching type supply adjustment device that controls the amount of coagulant supplied depending on the situation of the shield excavation section, and a pressure gauge and a flow rate are used as part of the backfilling material injection means. A method for backfilling a lining segment in shield construction according to claim 1 or 2, wherein a meter or the like is attached and the filling operation is performed by observing and detecting the flow of backfilling material using these meters. .