JPS6152317B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a face water pressure maintenance control method in the mud/sludge shield construction method, which excavates the ground and fluidly transports the excavated earth and sand while maintaining the stability of the face in pipe work such as sewerage. Regarding.

The mud/sludge shield method a) requires less auxiliary construction costs, b maintains the safety of the face and is closed, so there is less ground collapse, c does not lower the groundwater level, so there is less ground subsidence, and d there is less noise and vibration. It has advantages such as , etc., and is used for sewerage construction in urban areas. The flow of mud during bypass operation and excavation operation in the general mud/sludge shield construction method will be explained with reference to FIG. 1.

Bypass operation means that mud is pumped from the adjustment tank 1 to the mud pipe 3 by the mud pump 2 which controls the pressure, and this mud water is sent to the mud pipe 3 via the bypass valve 4 by the mud pump 5 which controls the flow rate. 6 and is returned to the adjustment tank 1 via the processing device 7. At this time, the face water pressure is maintained exclusively by the control valve 8 since the excavation valves 9 and 11 are closed.

Excavation operation means that mud is pumped from the adjustment tank 1 by the mud pump 2 to the face chamber 10 via the excavation valve 9, and then the excavated soil is transported to the processing device 7 via the excavation valve 11 and the mud removal pump 5, where it is processed. This is an operation in which the remaining muddy water is returned to the adjustment tank 1. in general,
Before starting the excavation operation, a bypass operation is first performed, and after the mud feeding water pressure and the mud discharge flow rate are stabilized, the excavation operation is switched to. As is well known, in pipe conduit construction, it is necessary to excavate while avoiding the collapse and uplift of the ground. Therefore, in the mud/sludge shield method, it is essential to stabilize the face 12. Conventionally, in order to stabilize the face, the second
As shown in the figure, it was operated only by a follow-up control (cascade control) device.

According to FIG. 2, which shows an instrumentation loop diagram of a conventional embodiment, the face water pressure indicating controller 16 during bypass operation.
The output signal controls the opening of the face holding control valve 8, and when excavation operation starts thereafter, the output signal is directly switched to the setting value of the mud feeding water pressure indicating regulator 17. Therefore, the output signal of the face water pressure indicating regulator 16 is switched from controlling the opening of the control valve 8 to controlling the rotation of the mud pump 2 at this point. At this time, a phenomenon occurs in which the face water pressure temporarily drops below the set value. That is, if the output of the face water pressure indicating regulator 16 that controls the control valve 8 during bypass operation is zero, control is performed to close the control valve 8 in response to this. When switching from this state to excavation operation, the normally closed contact 18 of the relay indicating that excavation is in progress is turned OFF, the normally open contact 19 is turned ON, and a cascade loop is formed.

As a result of such switching, the setting value applied to the mud feeding water pressure indicator controller 17 becomes zero, and this setting value causes the input signal to the rotation speed control device 20 of the mud feeding pump 2 to temporarily become zero. Become. Therefore, the rotational speed of the mud pump 2 decreases, thereby decreasing the face water pressure, and at the same time, the output of the face water pressure transmitter 13 also decreases, causing so-called hunting. but,
After a while, in order to compensate for the decrease in the output of the transmitter 13, the face water pressure indicator controller 16 starts to output an output corresponding to the deviation, so the face water pressure automatically approaches the set value, hunting ends, and a stable state is achieved.

When switching from excavation operation to bypass operation, a phenomenon occurs in which the water pressure at the face temporarily increases sharply. That is, during excavation operation, the output signal of the face water pressure indicator controller 16 controls the rotation speed control device 20 of the mud pump 2, and operates so that the signal of the face water pressure transmitter 13 approaches the face water pressure setting value. .
When switching from this state to bypass operation, the normally open contact 19 of the relay that indicates excavation is turned OFF, the cascade loop is released, and at the same time the normally closed contact 18 is turned ON, and the control valve 8 is connected to the face water pressure indicating controller. 16 outputs are applied.

Until now, during excavation operation, the control valve 8
The output signal from the face water pressure indicator controller 16 acts on the valve 8, which has been maintained in the closed state and the water pressure at the face is maintained. As a result, the mud feeding water pressure is applied to the face chamber 10 via the control valve 8 which receives an opening command.
This causes the water pressure at the face to temporarily increase rapidly.

It is clear that the phenomenon in which the face water pressure drops or rises rapidly every time the operating state is changed is contrary to the necessary requirements for preventing the collapse of the ground and for safe excavation. In order to avoid such pressure fluctuations, in conventional switching operations, when switching from bypass operation to excavation operation, the mud feeding water pressure indicator controller 1 is
The same value as the output signal value of 7 is sent to the face water pressure indicating controller 1.
The switching was performed after manual adjustment to the output signal value of 6. Furthermore, when switching from excavation operation to bypass operation, the switching was performed after the output signal value of the face water pressure indicating controller 16 was manually set to zero. However, such operations require delicate timing of switching operations by the operator, are complicated, and are prone to erroneous operations, which has been seen as a problem from the viewpoint of safety work.

The present invention provides the following features:
The purpose is to eliminate instability phenomena associated with pressure fluctuations.

The object of the present invention is to
This is achieved by the face water pressure maintenance control method of the mud shield method.

The face water pressure maintenance control method according to the present invention makes it possible to switch the operating state of the mud/sludge shield construction method while safely maintaining the face water pressure, making it possible to carry out safe pipe excavation work.

A face hydraulic protection control device suitable for carrying out the method according to the invention will now be disclosed with reference to FIGS. 3 and 4, which show suitable embodiments of the invention.

FIG. 3 shows a sequence diagram of an excavation operation memory circuit of an apparatus suitable for carrying out the method according to the present invention, and the select switch 21 is a switch with a residual contact. Further, an apparatus suitable for carrying out the face water pressure maintenance control method of the mud/sludge shield construction method according to the present invention can be configured as shown in FIG. 4. In FIG. 4, the same elements as in FIG. 2 are given the same reference numerals. Here, the face water pressure indicating regulator 16 and the mud feeding water pressure indicating regulator 17, which are important elements in the present invention, will be explained.

The face water pressure indicating controller 16 is the face water pressure transmitter 1
It receives the face pressure signal (feedback signal) from 3 as input and is set to generate an arbitrary face water pressure. During bypass operation, an output signal (PID output) for controlling the control valve 8 is generated. Further, during excavation operation, a setting value for the mud feeding water pressure indicating controller 17 is generated.

On the other hand, the mud feeding water pressure indicator controller 17 receives a pressure signal (feedback signal) from the mud feeding water pressure transmitter 15 and is a control device for a variable speed motor (not shown) that drives the mud feeding pump 2. 20. The setting value of the mud feeding water pressure indicator controller 17 is the mud feeding water pressure (sludge water pressure setting value) arbitrarily set manually during bypass operation, and the output value of the face water pressure indicator controller 16 during excavation operation. and set it as the set value.

Furthermore, during the time set by the timer while switching from bypass operation to excavation operation, the control input from the face water pressure regulator 16 that was adjusting the face water pressure to the control valve 8 is canceled, and at the same time, the mud feeding water pressure command is adjusted. A total of 17 setting signals are forcibly input to the face water pressure indicating controller 16. Through this operation, the set value of the face water pressure indicator controller 16 becomes equal to the set value level of the mud feeding water pressure indicator 17, and the muddy water filling the face can be circulated without sudden changes in pressure or hunting. . The operation of the embodiment apparatus of FIGS. 3 and 4 configured in this way will be disclosed. Now, when switching from bypass operation to excavation operation, select switch 21 is turned on and auxiliary relay X ₁ 22 is activated. By this operation, the contact point 18 shown in FIG. 4 turns OFF, and the output signal from the face water pressure indicator controller 16 to the control valve 8 is cut off. Therefore, the control valve 8 is operated to close. On the other hand, the contact 23 of the auxiliary relay X ₁ 22 is turned on, and thereby the timer TR ₁ 24 is activated. more relay
Contact 25 of X ₁ 22 is also turned ON, and timer TR ₁ 2
The setting value signal of the mud feeding water pressure indicating regulator 17 is forcibly applied to the output side of the face water pressure indicating regulator 16 through a series circuit with the time-limited opening contact 26 of No. 4. When the set time has elapsed, the time-limited open contact 26 of the timer TR ₁ 24
turns OFF and at the same time time-limited closing contact 27 turns ON, auxiliary relay R ₁ 28 operates and contact 19 turns ON.
becomes. As a result, the output of the face water pressure indicator controller 16 is input to the mud feeding water pressure indicator controller 17 via the contact 19, and the normal cascade control is resumed.

Next, the operation when switching from excavation operation to bypass operation is as follows. The excavation operation memory circuit shown in FIG. 3 continues the excavation operation as described above by turning on the select switch 21. That is, relay X ₁ 22 indicating that digging is in progress is activated, timer TR ₁ 24 and relay R ₁ 28 are activated accordingly, and at the same time, contact 29 of relay X ₁ 22 causes set side S30 of the keep relay to be set. Yes, the excavation state is maintained. When the select switch 21 is turned OFF and bypass operation is selected, the relay X ₁ 22, the timer TR ₁ 24, and the relay R ₁ 28 are all turned OFF.
In this state, the normally closed contact 32 of relay X ₁ 22 is
It becomes ON, and the set side contact 3 of the keep relay
Since timer TR 1 is kept ON, timer TR ₂
33 and relay R ₂ 34 are activated. In this state, the normally closed contact 35 of the relay R ₂ 34 is turned OFF, and the output signal circuit of this controller 16 is turned OFF inside the face water pressure indicating controller 16, making the output zero. Relay X ₁ indicating in this case drilling operation
The normally closed contact 18 of 22 is turned ON, and the output signal (zero) of the face water pressure indicator controller 16 closes the control valve 8 via the contact 18. Thereafter, after the set time of the timer TR ₂ 33 has elapsed, the contact point 36 is turned ON, and the reset side coil R37 of the keep relay is activated, thereby canceling the memory during excavation. At the same time, the set side S3 of the keep relay, which memorized the excavation
0 contact 31 turns OFF, so timer TR ₂ 33 and relay R ₂ 34 turn OFF,
The relationship between the face water pressure indicating regulator 16 and the mud feeding water pressure indicating regulator 17 is discontinued, each returning to independent control and entering a steady operating state. As described above, according to the method according to the present invention, during the time set by the timer when switching from bypass operation to excavation operation, the set output of the mud feeding water pressure indicating controller 17 is forcibly changed to the face as shown in FIG. It is input to the water pressure indicating controller 16. This condition is maintained while the muddy water moves into the face (machine bulkhead). Therefore, the output of the face water pressure indicator controller 16 becomes an approximate value to the output of the mud feeding water pressure indicator controller 17.

After the timer setting time has been reached, the output of the face water pressure indicating regulator 16 is input to the mud feeding water pressure indicating regulator 17 to control the speed of the variable speed motor that drives the mud feeding pump 2 to maintain the face water pressure at a predetermined value. It is something to control. By performing such control, the set value forcibly input and the feedback value from the face pressure transmitter 15 are approximately approximate values. Therefore, sudden changes in pressure and hunting do not occur. Although FIG. 4 illustrates the above operation by arranging a timer contact and a switching contact between both indicating controllers, in reality, it is convenient to include such operations in the indicating controller itself.

By the control method according to the present invention as described above,
This simplifies the operation of monitoring the return flow by adjusting the instruments for operators in the return system of the mud/sludge shield construction method, and the stable water pressure at the face can be easily maintained, allowing safe and reliable pipe construction.

Although the present invention has been disclosed based on suitable embodiments thereof, it will be obvious to those skilled in the art that other modifications and changes can be made within the scope of the present invention.

[Brief explanation of the drawing]

Figure 1 is a flow diagram of the return equipment in the general mud/sludge shield method. FIG. 2 is a conventional instrumentation loop diagram compatible with FIG. FIG. 3 is a sequence diagram of the excavation operation memory circuit of the control device for implementing the method according to the present invention. FIG. 4 is an instrumentation loop diagram of a control device for implementing the method according to the invention. The correspondence of the main reference symbols in the figure is as follows.
1: Adjustment tank, 2: Sludge pump, 3: Sludge pipe, 4:
Bypass valve, 5: Sludge pump, 6: Sludge pipe,
7: processing device, 8: face holding control valve, 9: excavation valve, 10: face chamber, 11: excavation valve, 12: face surface, 13: face water pressure detector,
14: Excavator (katsuta), 15: Mud feeding water pressure detector, 16: Face water pressure indicating controller, 17: Mud feeding water pressure indicating controller.

Claims (1)

[Scope of Claims] 1. A face water pressure indicating and adjusting device that receives a face water pressure as an input and controls a face holding control valve during bypass operation, and generates a set value for mud feeding water pressure during an excavation operation, and a mud feeding water pressure as an input. In a face water pressure maintenance control method of mud water/sludge shield construction method, comprising: a mud feeding water pressure indicating and adjusting device that controls mud feeding water pressure by changing the rotation speed of a mud feeding pump according to the set value in response to water pressure, When switching the operating state from bypass operation to excavation operation, the control valve 8 for maintaining the face pressure is closed, and at the same time, the setting signal of the mud feeding water pressure indication adjustment device 17 is forcibly input to the face water pressure indication adjustment device 16. , After the time set by the timer when switching the operating state has elapsed, the mud feeding water pressure indication adjustment device 17
At the same time, the forced input to the face water pressure indication and adjustment device 16 is released, and at the same time, the output of the face water pressure indication and adjustment device 16 is given as the setting value of the mud feeding water pressure indication and adjustment device 17, and the control by the face water pressure of the face water pressure indication and adjustment device 16 is performed. , and shifting to cascade control in combination with control by the mud feeding water pressure of the mud feeding water pressure indicating and adjusting device 17.