JPS6156759B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for controlling the amount of soil taken in by a device that propels a medium diameter pipe (250 to 600φ) after accurately introducing and burying a small diameter lead pipe between a starting shaft and a destination shaft. It is something.

Conventionally, as shown in Fig. 1, after a leading pipe c is buried from a starting shaft a to a reaching shaft b using a small diameter pipe propulsion device (not shown) whose direction can be adjusted, a medium diameter pipe propulsion device d (this In consideration of the space in the shaft, a buried pipe e was attached to a hydraulic motor etc.), and it was propelled by a propulsion device f.

A cutter provided in the medium-diameter pipe propulsion device d excavates and introduces earth and sand into the shaft, and a screw conveyor g installed in the leading pipe delivers the earth and sand to the shaft b.
transport to.

The transported and discharged earth and sand is collected in the earth removal tank of reaching pit b and is discharged to the ground.

The problem with this method is that the soil is transported inside the leading pipe c by the screw conveyor g.
The inner surface is worn and the strength is insufficient, which is due to the lead pipe c.
This is undesirable as it leads to tube buckling during propulsion.

Another drawback was that the screw conveyor g was clogged with earth and sand, making it impossible to propel it due to insufficient torque.

In order to improve this drawback, the present applicant previously proposed a construction method in which excavated earth and sand is transformed into a slurry and transported.

That is, the leading pipe is moved from the starting hole 50 to the reaching hole 51.
After laying the pipe, a pipe propulsion device 52 is attached to the rear end of the leading pipe, and the pipe propulsion device 52 excavates the ground and transports the excavated earth and sand to the pipe propulsion device 52.
The pipe propulsion device 5 takes water into the pipe and uses the leading pipe to
2, the water is mixed with the excavated earth and sand to make the earth and sand into slurry, and the slurry earth and sand is discharged to the reaching shaft 51 side, and the buried pipe 55 attached to the rear end of the pipe propulsion device 52 is moved to the starting shaft. This is a pipe burying method in which the buried pipe 55 is buried underground by pushing from the 50 side.

However, in this construction method, the pressure P ₂ inside the cut head (determined by the resistance of the slurry transport pipe) is not the same as the water pressure P ₁ (water pressure) in the ground.

When the water pressure P ₁ is large (0.3 kg/cm ² or more), P ₁ > P ₂ , water infiltrates from the ground, and along with it, earth and sand also flows into the katsuta head. For this reason, more excavation is performed than the volume S×L (theoretical excavation amount) determined by the excavation distance L and the area S of the propulsion machine cutter.

Therefore, it causes ground subsidence. This phenomenon is particularly noticeable on sandy soils that are not self-sustaining.

The present invention has been made in view of the above circumstances, and its purpose is to prevent excessive inflow of earth and sand into the pipe propulsion device side due to the flow of soil, and to enable excavation according to the theoretical excavation amount. An object of the present invention is to provide a method for controlling the amount of soil taken in by a buried propulsion device.

Hereinafter, embodiments of the present invention will be described based on FIG. 3 and subsequent figures.

Reference numeral 1 in the drawings indicates a tube propulsion device, and this tube propulsion device 1 is provided with a cutter head 2 at its front end. A sand intake port 3 and a cutter 4 are provided at the front end of the cutter head 2. Further, a stirring plate 6 is provided inside the cutter head 2 and is attached to the cutter head 2 via a bracket 5.

In the drawing, reference numeral 7 denotes a connecting pipe. The connecting pipe 7 passes through the cutter head 2 and is connected to the tube propulsion device 1, and a threaded connecting pipe 8 is formed at the front end of the connecting pipe 7. An input port 9 is formed in the connecting pipe 7.

A slurry pipe pinch valve 10 is provided in the connecting pipe 7, and a funnel-shaped inlet pipe 11 is attached to the rear end of the slurry pipe pinch valve 10.

A slurry pressing water pipe 12 is provided on the outer periphery of the connecting pipe 7.
and stirring water pipes 13 are attached, and these water pipes 12 and 13 are provided with water pipe pinch valves 14 and 15. The rear part of the slurry pressing water supply pipe 12 is inserted into the connecting pipe 7, and a slurry pressing nozzle 16 is attached to the end thereof, and these constitute a pressing water mechanism A. The rear part of the stirring water supply pipe 13 is inserted into the connecting pipe 7, and the stirring water supply pipe 13 is provided with a nozzle 17 for preventing slurry precipitation and a nozzle 18 for stirring the slurry, which constitute a water supply mechanism B. There is.

The slurry pressing nozzle 16 faces the center of the inlet of the inlet pipe 11, the slurry precipitation prevention nozzle 17 faces the end of the inlet of the inlet pipe 11, and the slurry stirring nozzle 18 is located inside the cutter head 2. is facing.

A screw conveyor 19 is provided within the connecting pipe 7 and receives rotational driving force from the pipe propulsion device 1.

Compressed air is supplied to the slurry pipe pinch valve 10 and the water pipe pinch valves 14, 15 through pipes 20, 21, 22 from a ground compressor 43.

In the drawing, 23 is a leading pipe, and this leading pipe 23 has a connecting part 24 connected to the connecting part 8 of the connecting pipe 7.
A water pipe 25 connected to the slurry pressing water pipe 12 and a water pipe 26 connected to the stirring water pipe 13 are attached to the outer periphery of the connecting pipe 7.

In the drawing, reference numeral 30 denotes a slurry pipe, the rear end of which is connected to the slurry pipe pinch valve 10, and a flow control valve 31 is attached to the tip of the slurry pipe 30.

The pipe propulsion device 1 has a water pressure P ₁ and a cutter internal pressure.
A differential pressure detector 48 for detecting P ₂ is provided, and an output signal 49 of this differential pressure detector 48 is sent to the differential pressure control device 4.
5, and the control valve 31 is controlled by the output signal.

Next, the operation will be explained.

First, the leading pipe 23 is buried in the reaching shaft 33 from the starting shaft 32 using a small-diameter pipe propulsion device (not shown) whose direction can be adjusted, and then the leading pipe 23 is connected to the connecting pipe 7 of the tube propulsion device 1 . In this case, the water pipes 25 and 26 of the connecting pipe 23 are connected to the slurry pressing water pipe 12 and the stirring water pipe 13, and the water pipes 25 and 26 are pumped through pipes 34 and 35 arranged in the reaching hole 33. It is connected to the discharge side of 36. The pump 36 is provided in a water tank 37, and the water tank 37 receives water from a sedimentation tank 38.

Further, a slurry pipe 30 is inserted into the leading pipe 23, and this slurry pipe 30 is connected to the slurry pipe pinch valve 1.
Connected to the exit side of 0. Slurry pipe 30 is connected to soil removal tank 39.

A sand pump 40 is provided in the soil removal tank 39 , and the discharge side of the sand pump 40 is connected to the settling tank 38 via a pipe 41 .

The cutter head 2 is driven by the tube propulsion device 1.
Rotate and excavate the ground with cutter 4, and thrust device 4
Propelled by 3'.

The earth and sand excavated by the cutter 4 is taken into the cutter head 2 through the intake port 3. Water supplied to the stirring water pipe 13 by driving the pump 36 is injected from the slurry stirring nozzle 18 into the earth and sand. Further, as the cutter head 2 rotates, the earth and sand are stirred by the stirring plate 6, and the earth and sand in the cutter head 2 is turned into a slurry.

The slurry of earth and sand is transferred to the screw conveyor 19.
Pinch valve 1 for slurry pipe from inlet pipe 11 by
0 into the slurry tube 30.

At this time, the earth and sand made into slurry by the water ejected from the slurry pressing nozzle 16 is transferred to the slurry pipe 3.
Pressed within 0.

Further, the water injected from the slurry precipitation prevention nozzle 17 prevents sedimentation of earth and sand at the inlet portion of the inlet pipe 11.

The earth and sand transported by the slurry pipe 30 enters the soil removal tank 39, and the water that overflows the sedimentation tank 38 due to the drive of the sand pump 40 enters the water supply tank 37.

The above is the function of the propulsion device, but the control method of the present invention is not only applicable to the propulsion device shown in this embodiment, but also applies to the propulsion device by breaking up the earth and sand by means other than cutters based on the principle shown below. It can be applied to any type of propulsion device as long as it has a structure that incorporates it. Next, the control method of the present invention will be explained.

When the flow rate control valve 31 is opened or closed, the valve pressure loss changes as shown in FIG. Therefore, the pressure P ₂ inside the cutter head 2 is increased or decreased as follows: P ₅ = valve pressure loss + slurry pipe pressure loss.

In this way, the internal pressure _P2 of the cutter head 2 can be controlled by the flow rate control valve 31.

If P ₁ > P ₂ (direction c in which the flow rate control valve 31 is opened in Fig. 6), water flows in from the external ground.

If P ₁ <P ₂ (direction a in which the flow rate control valve 31 is closed in FIG. 6), water is released to the outside.

When P ₁ = P ₂ , no water flows in or out from the external ground. In this case, the quicksand flow phenomenon disappears and the theoretical excavation amount S×L can be taken in.

From the above point of view, if the water supply amount Q ₁ and the slurry flow rate Q ₂ are made equal by adjusting the opening degree of the flow rate control valve 31, no water will flow in or out.

That is, it is sufficient to know the slurry flow rate Q ₂ and change the opening degree of the flow rate control valve 31 to make it equal to the water supply amount Q ₁ .

Also, the conditions for P ₁ = P ₂ change slightly due to the introduction of earth and sand.

In other words, if the amount of water conveyed is Q ₁ /min and the amount of soil intake is g/min, then q = S・V ...... (1) S is the area of the sediment intake port, V is the propulsion speed, and Q ₂ = Q ₁ + q. =Q ₁ +S・V……(2) q=S・V is generally a few percent of Q _1. When the propulsion speed V is small, it can be ignored.

However, when the propulsion speed V is large, the slurry flow rate Q ₂ can be determined using equation (2).

Figure 7 shows the dependence of the slurry flow rate _Q2 on the amount of excavation.

Experimental data is q/Q ₁ = 7% Propulsion speed V = 20
cm/min.

According to this, it can be seen that Q ₁ = Q ₂ is almost good.

In addition, when more accurate excavation is desired or when the propulsion speed is high, the value of the optimum slurry flow rate Q ₂ changes due to fluctuations in the propulsion speed V.

That is, since a variation in V in equation (2) changes the value of Q ₂ , the best way to determine the optimum conditions for preventing water from entering the cutter is to control P ₁ =P ₂ . This is because if there is no infiltration of water, P ₁ =P ₂ .

Therefore, the differential pressure detected by the differential pressure detector 48 that measures the differential pressure between P ₁ and P ₂ is converted into an electrical signal 49 and sent to the starting shaft 32 side from the ground to the control device 45 in the arrival shaft 33 and inputted to the control device 45 in the arrival shaft 33 to control the flow rate. Adjust the opening degree of the control valve 31 to P ₁
-P ₂ should be zero.

The present invention has been described in detail above, and the leading pipe 23
After laying the pipe from the starting shaft 32 to the reaching shaft 33, the pipe propulsion device 1 is attached to the rear end of the leading pipe 23, and the pipe driving device 1 takes in earth and sand, and the hollow part of the leading pipe 23 or a part of the leading pipe 23 is In this construction method, water is supplied to the pipe propulsion device 1 using water, and the earth and sand taken in this water is mixed to form a slurry and discharged to the reaching shaft side. Obtained water pressure P ₁ and internal pressure P ₂ of cutter head 2
Since the valve opening degree of the flow control valve 31 provided in the conveying section that conveys the slurry is controlled so that the differential pressure (P ₁ - P ₂ ) between the slurry and the slurry is zero, the differential pressure (P ₁ - P 2 )
By controlling the opening degree of the flow rate control valve 31 so that P ₂ ) becomes zero, it is possible to prevent excessive inflow into the pipe propulsion device 1 side due to the flow of earth and sand, and to excavate according to the theoretical excavation amount.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a conventional pipe burying method, Fig. 2 is an explanatory diagram of a pipe burying method, and Fig. 3 is an explanatory diagram of a pipe burying method equipped with a method for controlling the amount of soil taken in according to an embodiment of the present invention. , Figure 4 is a vertical cross-sectional view of the part shown in Figure 3, Figure 5 is a front view of the cutting head, Figure 6 is a pressure distribution diagram of the slurry transport path, Figure 7 is a diagram of the relationship between slurry flow rate and excavation amount, and Figure 8 is a diagram of the relationship between slurry flow rate and excavation amount. 1 is a schematic explanatory diagram of the present invention. 1 is a tube propulsion device, 23 is a leading pipe, and 31 is a flow control valve.

Claims (1)

[Claims] 1 After laying the leading pipe 23 from the starting shaft 32 to the reaching shaft 33, the pipe propulsion device 1 is installed at the rear end of the leading pipe 23.
is installed, and the soil is taken in by the tube propulsion device 1.
In the method of supplying water to the pipe propulsion device 1 using the hollow part of the leading pipe 23 or a part of the leading pipe 23, mixing the earth and sand taken in this water to form a slurry, and discharging the earth to the reaching shaft side, The slurry is conveyed so that the differential pressure (P ₁ - _{P 2} ) between the water pressure P ₁ obtained by the differential pressure detector 48 provided in the tube propulsion device 1 and the internal pressure P ₂ of the cutter head 2 becomes zero. A method for controlling the amount of soil taken in by a buried pipe propulsion device, characterized in that the opening degree of a flow rate control valve 31 provided in a conveying section is controlled.