JPH03217597A - Back-filling injection method in shield tunelling method - Google Patents

Abstract

PURPOSE:To obstruct admixture of two liquids and to prevent the blockade of a pipe line by providing a by-pass pipe line to change over with a three way cock to an auxiliary agent side pipe line of a two liquids type back-filler, and providing a solenoid valve to a main agent side pipe line to send the auxiliary agent back to a tank in the event of suspension of work. CONSTITUTION:In the event of buck-filling grouting, a three way cock 10 is changed to a pipe line 4 side, and when a drain 18 is shutted to drive pumps P1 and P2, the solenoid valve 14 is opened, and pressure-feed of A and B liquids is made along pipe lines 3 and 4 to join at a Y-shaped pipe 7. In addition, it is discharged to a gap (d) from an injection pipe 6 through a connection pipe 6a to solidify. Then, when a device is stopped for a while, work is suspended and, at the same time, the pump P2 is stopped, the three way cock 10 is changed to a by-pass pipe 12 side for a specific time, and remaining pressure in the pipe line 4 is eliminated. Several seconds after, the pump P2 is stopped and, at the same time, the solenoid valve 14 is closed to leave the A liquid. According to the constitution, solidification caused by admixture of two liquids can be prevented.

Description

[Detailed Description of the Invention] <<Industrial Application Field>> The present invention relates to a backfill injection method in a shield construction method, and specifically aims to solve the problem of consolidation in a backfill injection method using a two-component backfill material. Regarding the method.

<Conventional Technology> In the shield construction method, excavation is performed by adding segments sequentially as the shield advances.

At this time, gaps are created between the outer circumferential surfaces of the skin plates and segments that constitute the outer circumferential surface of the shield tunneling machine and the ground.

The creation of void spaces due to these gaps can cause ground subsidence, so the basic measure to prevent ground subsidence is to quickly inject backfill material into the void spaces as shield excavation progresses.

In this backfilling method, there is a method in which a two-component fast-curing backfilling material is used to promote solidification of the backfilling material, and these are mixed immediately before injection.

Fig. 4 shows an injection device using the two-component type backfilling material, in which 1 is a tank containing the main agent (hereinafter referred to as A-liquid);
2 is a tank containing an auxiliary agent (hereinafter referred to as B liquid).

Each tank 1, 2 is connected via a connecting pipe 6a to a backfill injection pipe 6 arranged on the outer periphery of the skin plate 5 through each pump PI, P2 for pressure feeding and each pipe line 3, 4. The pipes 3 and 4 are joined by a Y-shaped pipe 7 before being connected to the injection pipe 6.

Then, by operating each pump PI, P2, each tank 1
, 2 flows through each pipe line 3, 4, and Y
They join together at the cross-shaped pipe 7, and from this point on, they flow in a mixed state, are discharged from the injection pipe 6, and are filled into the gap d between the segment 8 and the ground 9 located at the rear of the skin plate 5, and in this state. harden.

In addition, in this injection method, in order to prevent underground water from flowing back into the injection pipe 6, only liquid A is left in the pipe when the operation is stopped, and the pipe remains filled.

<<Problem to be solved by the invention>> However, in the injection method using this injection device, once the A liquid and the B liquid are mixed, they solidify early, so it is necessary to temporarily stop the operation. If the pumps Pl and P2 stop pumping at the same time, liquids A and B are used to coexist, especially after the convergence, that is, in the area beyond the Y-shaped pipe 7, and block the pipe line.

For this reason, the conventional method has been to first stop the pressure feeding of the B liquid and then stop the force feeding of the A liquid several seconds later to prevent the B liquid from remaining beyond the merging point.

However, in reality, even if the pumping of liquid B is stopped, some residual pressure causes it to flow into liquid A, and the portion into which it flows solidifies, causing the pipe line to become clogged.

This invention solves the above problems, and aims to provide a backfill injection method in the shield construction method that does not mix liquids A and B when the operation is stopped and prevents clogging of the pipeline. 0 target.

<<Means for Solving the Problems>> In order to achieve the above object, the present invention provides a bypass line that can be switched by a three-way cock in the auxiliary agent steel line, and also provides a solenoid valve at a position immediately before the confluence of the main agent side line. established,
At the same time as stopping the backfill material, the auxiliary steel pump is stopped, the three-way cock is switched, and the auxiliary agent remaining in the auxiliary steel pipe is returned to the tank via the bypass pipe, and then the auxiliary material is pumped for a predetermined period of time. The main agent side pump is stopped at a delayed timing, the solenoid valve is closed, and only the main agent is left behind from the confluence point to the injection pipe.

Further, in the present invention, a check valve mechanism may be provided at the junction of the auxiliary agent steel pipe line with the main agent side pipe line to open the flow path using pump pressure.

《Operation》 By switching the three-way cock to the bypass pipe side at the same time as the pump stops, the residual pressure when the pump stops acts on the bypass pipe side, and the auxiliary agent in the auxiliary steel pipe line is returned to the tank side through the bypass pipe. It will be done.

When the operation of the main agent side pump is stopped after a predetermined time delay, the already mixed backfilling material is discharged from the injection pipe, and only liquid A is filled inside the injection pipe, and the solenoid valve is closed to keep the filling state inside the pipe. This can be left in place to prevent underground water from flowing backwards.

By providing a check valve mechanism, it is possible to prevent the main agent from entering the auxiliary agent steel pipe line after the pumping is stopped.

<<Example>> Hereinafter, an example of the present invention will be described in detail using the drawings.

FIG. 1 shows a backfilling injection device to which the present invention is applied.

In this embodiment, parts that are the same as or corresponding to the conventional ones are given the same symbols, and only different parts or newly added parts are given different symbols for explanation.

The device applied to this invention is almost the same as the conventional one, and includes a backfilling injection pipe 6 that is arranged around the outer periphery of the skin plate 5 of the shield excavator and has a discharge port facing the segment 8 side, and a backfilling injection pipe 6 that has one end connected to the injection pipe 6. A connecting pipe 6a that is connected and protrudes inside the shield by penetrating the skin plate 5, and liquid A that is connected to the other end side of this connecting pipe 6a and joins through the Y-shaped pipe 7 just before the connection. The side pipe 3 and the B liquid side pipe 4, the tanks 1 and 2 storing liquids A and B, respectively, and the pumps PI and P2 that pump liquid A and B through the respective pipes 3. We are prepared.

The main body portion 7a of the Y-shaped tube 7 is continuous with the A liquid side pipe line 3, and is formed in such a shape that the connecting portion 7b of the B liquid side pipe line 4 is joined thereto.

The A liquid contained in the tank 1 is, for example, a water glass solution.

The liquid B stored in the tank 2 is a cement-based suspension, and the solidification time is adjusted mainly by increasing or decreasing the amount of cement.

In addition to the above configuration, the B liquid side pipe line 4 has a three-way cock 1.
A bypass pipe 12 is disposed through 0, and the discharge port of this bypass pipe 12 is connected to the B liquid side tank 2.

Further, a solenoid valve 14 is provided immediately before the connection between the A liquid side pipe line 3 and the Y-shaped pipe 7. This solenoid valve operates in conjunction with the pump P1, opens the flow path when the pump pt starts driving, and closes the flow path when the drive stops.

Further, reference numeral 16 is a cleaning jack provided on the back of the injection pipe 6, and 18 is a drainage drain interposed between the joint between the connecting pipe 6a and the Y-shaped pipe 7.

Next, a backfill injection method using the above equipment will be explained.

First, at the time of injection, the three-way cock 10 is switched to the pipe line 4 side, the drainage drain 18 is closed, and when each pump Pi, P2 is driven in this state, the solenoid valve 14 opens and the A liquid is poured.
Both liquid B is pumped through each pipe 3.4, joins at the Y-shaped pipe 7, and is further mixed from the injection pipe 6 through the connecting pipe 6a toward the gap d1 between the segment 8 and the ground 9, that is, the void space. It is discharged in this state and solidifies while filling the gap d.

As the shield excavates, it becomes necessary to newly assemble the segments 8, and when the shield excavation is stopped, it is necessary to temporarily stop the driving of the device. In this case, the following procedure is performed.

First, the pump P2 on the B liquid side is stopped at the same time as the propulsion work of the shield jack is stopped, and at the same time, the three-way cock 10 is switched to the bypass pipe 12 side for a predetermined period of time.

As a result, the B liquid remaining in the B liquid side pipe line 4 is released into the tank 2, and the residual pressure in the pipe line 4 is removed.

At this point, liquid A is flowing from pipe 3 to Y-shaped pipe 7 and connecting pipe 6a.
The backfilling material mixed with the B liquid has already been discharged, and the pressure feeding continues.

Therefore, a few seconds after the pump P2 is stopped and the switching operation is completed, the A liquid side pump PT is stopped and at the same time, the solenoid valve 1 is
When 4 is closed, Y-tube 7. Connection pipe 6a and injection pipe 6
The inside will remain filled with only liquid A.

Note that since no B liquid remains at the connection portion of the Y-shaped tube 7 with the B liquid side conduit 4, caking due to contact between the two prongs at the connection portion or within the B liquid side conduit 4 is also prevented.

In addition, as an example to more reliably prevent this kind of contact, as shown in FIG.
A check valve mechanism 20 is provided at the connecting portion 7b.

This check valve mechanism 20 includes a trapezoidal valve seat 20 formed in an expanded state at a connecting base of the connecting portion 7b to the main body portion 7a.
a trapezoidal valve body 20b that can be connected to the valve body 20b; a pair of guide posts 20c that are attached to both sides of the valve body 20b through the main body 7a; It is equipped with a compression coil spring 20d that biases the terminal toward the closing side.

The spring pressure of this spring 20d is set lower than the pumping pressure of the pump P2 and higher than the residual pressure.

Therefore, according to this configuration, the flow path of liquid B is dynamically blocked by stopping the drive of pump P2, so that the supply of liquid B can be reliably stopped, and the flow path of liquid A can be stopped in the liquid B side conduit 4. It is also possible to prevent the inflow of

Furthermore, FIG. 3 shows another example of the check valve mechanism 30, in which the tip of the connecting portion 7b is inserted into the inside of the main body 7a along the flow direction, and a strainer 30a is arranged at the tip, The outer periphery of the strainer 30a is surrounded by a rubber-like support sleeve 30b, and the tip of the strainer 30a is covered with a cap 30C.

In this embodiment, liquid B elastically expands the support sleeve 30b through the strainer 30a by pump pressure to open a flow path and joins liquid A flowing inside the main body 7a.

Furthermore, when the pressure is removed by stopping the operation of the pump P2, the support sleeve 30b elastically contracts and the flow path is closed. It is possible to reliably prevent inflow to the side.

<<Effects of the Invention>> As explained in detail through the embodiments above, the backfill injection method in the shield construction method according to the present invention can reliably prevent mixing of liquids A and B at the time of stopping pumping, and This can prevent problems such as caking.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing an injection device applied to the backfill injection method of the present invention, Fig. 2 is a partial sectional view showing an embodiment provided with a check valve mechanism, and Fig. 3 is a diagram showing an embodiment provided with a check valve mechanism. FIG. 4 is a partial sectional view showing another embodiment provided, and is an explanatory diagram of a conventional backfilling injection device. 1...A liquid side tank 2...B liquid side tank 3...A liquid side pipe line 4...B liquid side pipe line 5...Skin plate (shield excavator) 6... Backfill i Entry pipe 7...Y-shaped pipe 8...Segment 9...Ground d...Gap (void space) 10...Three-way cock 12...Bypass pipe 14...Solenoid valve 20 .30...Check valve mechanism

Claims (2)

[Claims] (1) A backfill injection pipe arranged on the outer periphery of the shield excavator, a main agent side pipe connected to this injection pipe, and an auxiliary agent side pipe that joins the main agent side pipe just before the above connection. , a backfill material comprising a tank storing a main agent and an auxiliary agent, and a pump for pumping the main agent and an auxiliary agent into respective pipes, and mixing the main agent and the auxiliary agent pumped through the respective pipes. In the backfill injection method in the shield construction method in which the liquid is discharged from the injection pipe: A bypass pipe that can be switched by a three-way cock is provided in the auxiliary agent side pipe, and a solenoid valve is provided at a position immediately before the confluence of the main agent side pipe. When the backfilling material is stopped, the auxiliary steel pump is stopped, and at the same time the three-way cock is switched to transfer the auxiliary agent remaining in the auxiliary side pipe into the tank via the bypass pipe. A backfill injection method in the shield construction method, characterized in that the main agent side pump is stopped at a timing delayed by a predetermined time, and the solenoid valve is closed. (2) A backfill injection method in the shield construction method according to claim 1, characterized in that a check valve mechanism is provided at the junction of the auxiliary agent side pipe with the main agent side pipe to open the flow path by pump pressure. .