JPH0791945B2 - Backfill injection method in shield method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a backfilling injection method in a shield construction method, and in particular, aims to solve the problem of consolidation in the backfilling injection method using a two-component type backfill material. Regarding the method.

<< Conventional Technology >> In the shield construction method, excavation is performed while successively adding segments as the shield advances. At that time, a gap is formed between the outer peripheral surface of the skin plate and the outer peripheral surface of the segment forming the outer peripheral surface of the shield machine and the ground.

Since the generation of void space due to this gap causes ground subsidence, it is a basic measure to prevent ground subsidence by injecting backfilling material into the void space early in accordance with the shield excavation.

In this backfilling method, there is a method of using a two-liquid type quick-curing type backfilling material in order to accelerate the solidification of the backfilling material and mixing them at a stage immediately before injection.

FIG. 4 shows an injection device using the two-liquid type backing material, and 1 is a tank containing a main component (hereinafter referred to as liquid A),
Reference numeral 2 is a tank containing an auxiliary agent (hereinafter referred to as liquid B).

Pumps P1 and P2 for pressure feeding and pipes 3 and 4
Is connected to the backfill injection pipe 6 arranged on the outer peripheral portion of the skin plate 5 via the connecting pipe 6a,
4 are joined by a Y-tube 7 before connecting to the injection pipe 6.

Then, the liquids A and B in the tanks 1 and 2 flow in the pipes 3 and 4 by the operation of the pumps P1 and P2, join at the Y-shaped pipe 7, and then flow in a mixed state from here on. Then, the injection pipe 6
Is discharged from the surface of the skin plate 5, is filled in the gap d between the segment 8 located at the rear portion of the skin plate 5 and the ground 9, and is cured in this state.

In addition, in this injection method, in order to prevent the backflow of groundwater into the injection pipe 6, only the liquid A is left in the pipe line and is kept filled when the operation is stopped.

<< Problems to be Solved by the Invention >> However, in the injection method using this injection device, once the liquid A and the liquid B are mixed, they are solidified early, so that the operation is temporarily stopped. When the pumps P1 and P2 are stopped from being pumped at the same time, there is a possibility that the liquid A and the liquid B may be mixed and the pipes may be blocked especially after the merging, that is, in the portion beyond the Y-shaped pipe 7.

For this reason, conventionally, the method of first stopping the pumping of the solution B and then stopping the pumping of the solution A after several seconds to prevent the solution B from remaining from the confluence point was taken.

However, in reality, even if the pumping of the liquid B was stopped, the residual pressure caused a slight residual pressure to flow into the liquid A side, and the flowed-in portion was solidified.

The present invention solves the above problems, and provides a backfill injection method in a shield construction method in which there is no mixing of liquids A and B when operation is stopped and blockage of a pipeline can be prevented. Has an aim.

<Means for Solving the Problem> In order to achieve the above-mentioned object, the present invention provides a bypass conduit that can be switched by a three-way cock in the auxiliary agent side conduit, and an electromagnetic valve at the position just before the main agent side conduit joins. Is provided
When the backing material is stopped, the auxiliary agent side pump is stopped, and at the same time, the three-way cock is switched to return the auxiliary agent remaining in the auxiliary agent side pipeline into the tank through the bypass pipeline, and then a predetermined amount. The main agent side pump is stopped at a timing delayed, and the solenoid valve is closed to leave only the main agent from the junction to the injection pipe.

Further, in the present invention, a check valve mechanism may be provided at the junction of the auxiliary agent side conduit with the main agent side conduit to open the channel by the pump pressure.

<Action> By switching the three-way cock to the bias pipe side at the same time as stopping the pump, the residual pressure when the pump is stopped acts on the bypass pipe side, and the auxiliary agent in the auxiliary agent side pipeline is returned to the tank side through the bypass pipe. Be done.

When the operation of the main agent side pump is stopped after a predetermined time delay, the already mixed backfill material is discharged from the injection pipe, the inside of the injection pipe is filled only with the liquid A, and the inside of the pipe remains filled by closing the solenoid valve. It is left behind and can prevent backflow of groundwater.

By providing the check valve mechanism, it is possible to prevent the main agent from entering the auxiliary agent side conduit after the pressure feeding is stopped.

<< Embodiment >> An embodiment of the present invention will be described in detail below with reference to the drawings.

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

In this embodiment, the same or corresponding parts as in the conventional case will be denoted by the same symbols, and different parts or newly added parts will be described by using different reference numerals.

The device applied to the present invention is arranged almost in the same manner as the conventional one, and is arranged on the outer periphery of the skin plate 5 of the shield machine, and has a back-filling injection pipe 6 whose discharge port is directed toward the segment 8 and one end of this injection pipe 6. Liquid A that is connected and connected to the connecting pipe 6a that penetrates through the skin plate 5 and projects inside the shield, and that is connected to the other end of this connecting pipe 6a and that merges via the Y-shaped pipe 7 immediately before the connection. Side conduit 3 and liquid B side conduit 4, tanks 1 and 2 storing liquids A and B, respectively, and liquids A and B
It is provided with pumps P1 and P2 for pumping the liquid through the respective pipelines 3 and 4.

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

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

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

In addition to the above configuration, a three-way cock 10 is provided in the B liquid side conduit 4.
A bias tube 12 is disposed through the discharge port of the bias tube 12 and is connected to the B liquid side tank 2.

In addition, a solenoid valve is provided immediately before the connecting portion between the liquid A side conduit 3 and the Y-shaped pipe 7.
14 are provided. This solenoid valve works with pump P1,
The flow path is opened when the drive of the pump P1 is started, and closed when the drive is stopped.

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

Next, a backfill injection method using the above apparatus will be described.

First, at the time of injection, the three-way cock 10 is switched to the pipeline 4 side, the drainage drain 18 is closed, and when the pumps P1 and P2 are driven in this state, the solenoid valve 14 opens and both liquids A and B are pipelines. It is pressure-fed along 3, 4 and joins at the portion of the Y-shaped pipe 7, and is further discharged from the injection pipe 6 through the connection pipe 6a toward the gap d between the segment 8 and the ground 9, that is, the void space, in a mixed state, It solidifies in the state of filling the gap d.

It is necessary to newly assemble the segment 8 along with the excavation of the shield, and it is necessary to temporarily stop the driving of the device when the shield excavation is stopped. In this case, the following procedure is performed.

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

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

At this point, the liquid A has been pressure-fed from the conduit 3 through the Y-shaped pipe 7 and the connecting pipe 6a into the injection pipe 6, and has been pressure-fed after the backing material already mixed with the liquid B has been discharged. Is persistent.

Therefore, when the liquid A side pump P1 is stopped and the solenoid valve 14 is closed at the same time a few seconds after the pump P2 is stopped and the switching operation is completed, only the A liquid is filled in the Y-shaped pipe 7, the connecting pipe 6a and the injection pipe 6. It will be left in a standing state.

Since the B liquid does not remain in the connecting portion of the Y-shaped pipe 7 with the B liquid side conduit 4, the solidification due to the contact of both liquids in the connecting portion or the B liquid side conduit 4 is also prevented.

As shown in FIG. 2 as an embodiment for further surely preventing this kind of contact, as shown in FIG.
A check valve mechanism 20 is provided at the connecting portion 7b with the.

The check valve mechanism 20 includes a trapezoidal valve body 20b which can be connected to and detached from a trapezoidal valve seat 20a formed in an expanded state on a connection base portion of the connection portion 7b to the main body portion 7a, and both sides of the valve body 20b. And a pair of guide posts 20c attached to the main body 7a and a compression coil spring 20d interposed between the guide posts 20c and the guide post 20c for constantly urging the valve body 20b toward the closing side.

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

Therefore, according to this configuration, since the flow path of the B liquid is automatically shut off by stopping the driving of the pump P2, the supply of the B liquid can be surely stopped, and the A liquid and the B liquid side conduit 4 can be surely stopped. Inflow can also be prevented.

Further, FIG. 3 shows another example of the check valve mechanism 30. The tip of the connecting portion 7b is inserted inside the main body portion 7a along the flow direction thereof, and the strainer 30a is arranged at the tip thereof. 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, the liquid B joins the liquid A flowing in the main body 7a by elastically expanding the support sleeve 30b through the strainer 30a by the pump pressure to open the flow path.

Further, 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, so that the leakage of the liquid B or the liquid B of the liquid A at the time of the stop of the operation is performed as in the above embodiment. Inflow to the side can be reliably prevented.

<< Effects of the Invention >> As described in detail with reference to the embodiments above, in the backfill injection method in the shield method according to the present invention, it is possible to reliably prevent the mixing of the liquids A and B at the time of stopping the pumping, and Trouble such as solidification can be prevented in advance.

[Brief description of drawings]

FIG. 1 is an explanatory view 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 check valve mechanism. FIG. 4 is a partial sectional view showing another embodiment provided, and FIG. 4 is an explanatory view of a conventional backfill injection device. 1 ... A liquid side tank 2 ... B liquid side tank 3 ... A liquid side conduit 4 ... B liquid side conduit 5 ... Skin plate (shield excavator) 6 ... Backfill injection pipe 7 ... Y-shaped pipe 8 ... Segment 9 … Solid 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 a shield machine, a main agent side pipe connected to this injection pipe, and an auxiliary agent side pipe joined immediately before the connection of the main agent side pipe. Road,
A backing material, in which a tank storing the main agent and the auxiliary agent respectively, and a pump for pumping the main agent and the auxiliary agent to the respective pipelines are mixed, and a mixture of the main agent and the auxiliary agent pressure-fed in the respective pipelines is provided. In the back-filling injection method in the shield method of discharging from the injection pipe: a bypass conduit that can be switched by a three-way cock is provided in the auxiliary agent side conduit, and an electromagnetic valve is provided immediately before the joining of the main agent side conduit. , When the backing material is stopped, the auxiliary agent side pump is stopped, and at the same time, the three-way cock is switched to transfer the auxiliary agent left in the auxiliary agent side conduit into the tank through the bypass conduit. A back-filling injection method in a shield construction method characterized in that the main agent side pump is stopped at a timing after a predetermined time delay and the electromagnetic valve is closed. 2. The backfill in the shield construction method according to claim 1, wherein a check valve mechanism for opening a flow path by a pump pressure is provided at a confluence portion of the auxiliary agent side conduit with the main agent side conduit. Injection method.