JPH07324587A - Method to return shield linearly after bending in bending shield machine - Google Patents

Abstract

PURPOSE:To increase the controllability of jacks by retracting bend type jacks forcibly by shield jacks and adjusting and holding the pressure of oil in the bend type jacks on the extension side at a set pressure equivalent to the soil pressure and hydraulic pressure of a face surface when a shield is returned linearly after the shield is bent by the bend type jacks. CONSTITUTION:When bend type jacks 10a to 10h are retracted forcibly by shield jacks 8, the set pressure of a solenoid proportional relief valve 28 is adjusted so that a face hydraulic pressure measured by a face hydraulic pressure gauge 7 can be maintained at a specified value equivalent to a static soil pressure. In this case, the solenoid proportional relief valve 28 connected to a circuit through a solenoid valve 29 escapes the pressure oil on the extension side of the bend type jacks 10a to 10h to an oil tank 17 to maintain the pressure of oil in the bend type jacks 10a to 10h on the extension side at a set pressure equivalent to the face hydraulic pressure. Thus the bend type jacks 10a to 10h can be retracted without moving a front shield backward and also without biting a cutter head into the face.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for returning a shield to a straight line after a center break in a center break type shield machine used for shield work having a curved portion.

[0002]

2. Description of the Related Art In a mid-break type shield machine, the stroke of the mid-break jack connecting the front shield and the rear shield is changed left and right to bend the shield in the middle, and then the shield is made straight. At the time of returning it, the stroke was shortened by the retracting operation of the middle-breaking jack itself.

FIG. 5 shows a conventional center folding jack hydraulic circuit (details will be described later).

[0004]

However, as shown in FIG. 2, the shield jack 8 is attached to the rear shield 2 and the thrust of the shield jack 8 is transmitted to the front shield 1 via the center folding jack 10. In a shield machine, if you try to retract the middle-breaking jack by retracting it at one time, the front shield retracts and the gap between the front face of the cutter head and the face increases by the stroke of the middle-breaking jack. , It becomes impossible to maintain earth pressure and water pressure in front of the cutter head, which may lead to face collapse and eventually ground settlement. Therefore, while actually looking at the face earth pressure gauge and water pressure gauge, gradually bend the middle and shorten the jack,
At the same time or alternately, it is necessary to actuate the shield jack and to propel the shield by the amount of contraction of the center-folded jack, which complicates the jack operation.

An object of the present invention is to provide a center-break shield excavator having a structure in which the thrust of the shield jack is transmitted to the front shield via the center-break jack, without causing the face to collapse and allowing the cutter head to cut into the face. Without
It is an object of the present invention to provide a method of returning a shield to a straight line after a center break in a shield machine, which allows the middle break jack to be shortened only by operating the shield jack, thereby simplifying the jack operation.

[0006]

[Means for Solving the Problems] The above-mentioned object is to shield the center-folded jack from the retracting operation when the shield is folded back in the middle after the center-folded jack is folded. It is achieved by pressing and contracting with, and at the time of the pressing and contracting, the pressure on the extension side of the intermediate folding jack is adjusted and held at a set pressure corresponding to the earth pressure and water pressure of the face of the face.

Further, the above-mentioned object is to press the middle-breaking jack with the shield jack when the shield is returned to the straight shape after the shield is bent in the middle with the middle-breaking jack.
At that time, the earth pressure and water pressure on the face of the face and the pressure on the extension side of the middle bent jack are detected, and the detected values of the earth pressure and water pressure on the face of the face and the value of the pressure on the extension side of the center folded jack are kept in balance. It is achieved by adjusting the pressure on the extension side of the center-folded jack.

[0008]

[Function] After breaking the shield with the middle-breaking jack,
When returning the shield to a straight line, the center-folding jack itself is not retracted, but the shield jack at the corresponding position is extended and the center-folding jack is compressed by the thrust of the shield jack. At that time, if the set pressure on the extension side of the middle broken jack is adjusted to a value that corresponds to the earth pressure and water pressure (static earth pressure) of the face of the face measured with a face earth pressure gauge or water pressure gauge, the extension side pressure of the middle folded jack Is maintained at a set pressure that balances earth pressure and water pressure on the face of the face, and only by operating the shield jack,
Without causing the face to collapse, the cutter head does not cut into the face, and the center-folded jack can be shortened.

Further, as described in claim 2, while the middle broken jack is compressed by the shield jack, the earth pressure and water pressure of the face of the face at that time and the extension side pressure of the center folded jack are detected, and the face of the face is cut. If the pressure on the extension side of the middle-breaking jack is adjusted so that the detected values of soil pressure and water pressure on the extension side of the center-folding jack are balanced, the pressure on the face of the face will change according to changes in earth pressure and water pressure. The pressure on the extension side of the center-folded jack can be changed with high accuracy to respond more accurately.

[0010]

Embodiments of the present invention will be described below with reference to FIGS.

First, the structure of the shield portion of the center-breakable shield machine according to the present invention will be described. FIG. 2 is a longitudinal sectional view of a shield part when the present invention is applied to a muddy water pressure type shield, which is equipped with a cutter head 3, a cutter drive device 4, a mud pipe 5, a mud pipe 6, a face water pressure gauge 7 and the like. The front shield 1 and the rear shield 2 equipped with the shield jack 8, the segment assembling erector 9 and the like are joined by a center-breaking jack 10. Reference numeral 11 is a pin connecting the rod of the middle-breaking jack 10 and the mounting bracket 12 of the front shield 1, 13 is a pin connecting the head of the middle-breaking jack 10 and the mounting bracket 14 of the rear shield 2, and 15 is a front shield. 1 is a sand / sand seal interposed between the sliding portions of 1 and the rear shield 2. A plurality of shield jacks 8 and center folding jacks 10 are arranged along the inner circumference of the shield.

In the above construction, during curved construction, the stroke of the center-breaking jack 10 is changed between the left and right to cause the shield to be center-folded. The propulsion of the shield is performed by causing the shield jack 8 to act on the end surface of the segment 16 assembled in the rear shield 2 and transmitting the thrust to the front shield 1 via the center folding jack 10. FIG. 3 shows the shield operating state of the curved portion.

When the shield jack 8 is attached to the rear shield 2 and the thrust is transmitted to the front shield 1 via the center-breaking jack 10 as described above, the shield jack 8 is a skin plate of the rear shield 2 when the center is broken. Since it always expands and contracts in parallel with each other, the rod end of the shield jack 8 and the skin plate do not engage with each other, and the shield jack 8 can be pushed without being largely disengaged from the segment 16, so that construction of a sharp curve portion becomes easy.

When the shield is returned to the straight state from the center-folded state, the center-folded jack 10 itself is not retracted and the shield jack 8 at the corresponding position is extended, and the center-folded jack 10 is compressed by the thrust of the shield jack. . At this time, if the pressure on the extension side of the center-breakable jack 10 is lower than the face water pressure, the front shield 1 retracts, and if it is high, the cutter head 3 bites into the face. That is, the pressure on the extension side of the center-bending jack 10 must be maintained at a pressure that balances the face water pressure.

The structure of the center-bending jack hydraulic circuit that satisfies this condition will be described below with reference to FIG.

In FIG. 1, 17 is an oil tank for storing hydraulic oil, 18 is a pump unit that sucks hydraulic oil from the oil tank 17 and sends out pressure oil, and 19 is an unloading pressure (0 kgf / cm ² ) and an operating pressure (for example, 350
kgf / cm ² ) switchable pressure setting manifold, 20 is a pressure sensor that converts the operating pressure of the circuit into an electric signal and transmits it to the pressure gauge on the operation panel, and 21 is the center-bending jack 10a-10h operating speed. An electromagnetic proportional flow control valve that can be remotely controlled, 22a to 22d are the center folding jacks 10a to.
Solenoid valve with pilot operated check valve for selecting and locking push / pull (expansion / contraction) operation for 10h, 23a, 23b
Is an overload relief valve (safety valve) installed on the extension side and the contraction side of the center folding jacks 10a to 10h, respectively.
And the relief pressure is the maximum pressure of the circuit (in this case, 350k
gf / cm ² ). 24a to 24d are vacuum check valves on the extension side of the middle folding jacks 10a to 10h, and 25a to 25d are middle folding jacks 10a to 10h.
The check valves for relief on the extension side, 26a to 26d are vacuum check valves on the contraction side of the middle folding jacks 10a to 10h, and 27a to 27d are relief check valves on the contraction side of the middle folding jacks 10a to 10h. The configuration so far is the same as the conventional hydraulic circuit shown in FIG.

The difference of this embodiment from the conventional one is that an electromagnetic proportional relief valve 28, a solenoid valve 29, and a pressure sensor 30 are further added for holding the pressure on the extension side of the intermediate folding jacks 10a to 10h. The electromagnetic proportional relief valve 28 can adjust the set pressure to a value corresponding to the face water pressure, and when the middle bent jack is compressed by the shield jack, the relief on the extension side of the middle bent jack is kept at the set pressure. This is shown as a specific example of the valve. For example, the set pressure can be set to 10 by changing the magnitude of the input current.
It has a function that can be adjusted remotely in ~350kgf / cm ^2.

The solenoid valve 29 is a shield jack 8
The solenoid proportional relief valve 28 is connected to the circuit by operating only when the solenoid is operating. The pressure sensor 30 is provided for monitoring the overload pressure and the holding pressure on the extension side of the center-folded jack, and converts the measured pressure into an electric signal and transmits it to the pressure gauge on the operation panel.

In the present embodiment, the center folding jacks 10a-1.
When 0h is compressed by the shield jack 8, the set pressure of the electromagnetic proportional relief valve 28 is adjusted so that the face water pressure measured by the face water pressure gauge 7 is kept at a constant value corresponding to the static earth pressure. The electromagnetic proportional relief valve 28, which is connected to the circuit via 29, has
Since the pressure oil on the extension side of a to 10h is released to the oil tank 17 and the pressure on the extension side of the center-folded jacks 10a to 10h is maintained at the set pressure that balances the face water pressure, the front shield 1 does not retreat, and The cutter head 3 can retract the center folding jacks 10a to 10h without cutting into the face.

The solenoid proportional relief valve 28 is the solenoid valve 2
It may be directly connected to the circuit without going through 9, but in the present embodiment, the solenoid valve 29 closes the oil passage in the unlikely event that the electromagnetic proportional relief valve 28 is broken or a power failure occurs, and the intermediate break jack 10 is used.
The front shield 1 is prevented from retracting due to the pressure drop on the extension side of a to 10 h.

In the above embodiment, the case where the electromagnetic proportional relief valve 28 is used to set the pressure remotely by manual operation has been described, but the pressure setting can be automated.

FIG. 4 is a schematic diagram of an automatic control system for the pressure on the extension side of the middle broken jack. The face water pressure gauge 7 detects the water pressure on the face edge and the pressure sensor 30 detects the pressure on the extension side of the middle folded jack. The pressure setting is automated by comparing the detected amounts with an analog or digital arithmetic control unit 31 and controlling the input current of the electromagnetic proportional relief valve 28 so that the detected amounts are balanced.

[0023]

According to the present invention, in a medium-break shield excavator configured to transmit the shield jack thrust to the front shield via the middle-break jack, the face collapses when the shield is returned from the center-break state to a straight line. In addition, the cutter head does not bite into the cutting face, and you can shrink the middle bent jack only by operating the shield jack,
This has the effect of simplifying the jack operation.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of a center-folded jack according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of a shield section showing an example of a center-bending type shield machine to which the present invention is applied.

FIG. 3 is an explanatory diagram showing a shield operating state of a curved portion.

FIG. 4 is a schematic diagram of an automatic pressure control system for a center-folded jack extension side.

FIG. 5 is a hydraulic circuit diagram of a conventional center-folded jack.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Front shield, 2 ... Rear shield, 3 ... Cutter head, 7 ... Face water pressure gauge, 8 ... Shield jack, 10 ... Middle break jack, 28 ... Pressure holding relief valve (electromagnetic proportional relief valve), 29 ... Solenoid Valve, 30 ... Pressure sensor on the side where the middle bent jack extends, 31 ... Arithmetic control device.

Claims (3)

[Claims] 1. A center-break type shield excavator having a structure in which a front shield and a rear shield are joined by a center-breaking jack and the thrust of a shield jack mounted on the rear shield is transmitted to the front shield via the center-breaking jack. , When the shield is folded in the middle with the middle-breaking jack and then the shield is returned to the straight shape, the middle-breaking jack itself does not pull in, but the middle-breaking jack is compressed with the shield jack. A method for returning the shield to a straight line after a center break in a center break type shield machine, which is characterized by adjusting and holding the extension side pressure of the face to a set pressure corresponding to the earth pressure and water pressure of the face. 2. A center-break type shield excavator having a structure in which a front shield and a rear shield are joined by a center-breaking jack, and the thrust of a shield jack mounted on the rear shield is transmitted to the front shield via the center-breaking jack. When the shield is folded back in the middle with the middle-breaking jack and the shield is returned to the straight line, the middle-breaking jack itself does not pull in and the middle-breaking jack is compressed with the shield jack, and the earth pressure of the face at that time, Detecting the water pressure and the pressure on the extension side of the middle folding jack, the extension side of the center folding jack is maintained so that the detected values of the earth pressure and water pressure on the face of the face and the extension side pressure of the middle folding jack maintain balance. A method of returning a shield to a straight line after a center break in a center break type shield excavator characterized by adjusting the pressure. 3. A center-break type shield excavator having a structure in which a front shield and a rear shield are joined by a center-breaking jack and the thrust of a shield jack mounted on the rear shield is transmitted to the front shield via the center-breaking jack. , When the shield is folded back in the middle with the middle-breaking jack and the shield is returned to the straight shape, the middle-breaking jack itself does not pull in and the middle-breaking jack is compressed with the shield jack, and the earth pressure of the face at that time, Detecting the water pressure and the pressure on the extension side of the middle-breaking jack, the extension side of the middle-breaking jack should be maintained so that the detected values of earth pressure and water pressure on the face of the face and the detection value of the extension-side pressure of the center-breaking jack are balanced. A method of returning a shield to a straight line after a center break in an excavator with a center break type characterized by automatically adjusting the pressure.