JPS6132458B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring the air pressure inside a box working room in the air submersible box construction method when submerging an underground structure.

Conventionally, the pressure of the compressed air supplied to the submersible box work chamber was set by taking into account the groundwater level in the ground surveyed in advance and the position of the cutting edge of the submersible box working chamber. Assuming a water pressure of was taken.

With these conventional methods, if the groundwater level fluctuates in conjunction with the tide level of the seawater, or if the submersible is buried at a deep location and a water level lowering method is used in combination, the groundwater level may change. became unstable, and it was difficult to set an appropriate pressure inside the box in the box working room.

If the pressure inside the box is higher than the groundwater level, the air inside the work chamber will blow from the cutting edge through the ground and overland, increasing air consumption.

Furthermore, if the pressure inside the box was lower than the groundwater level, groundwater would infiltrate into the work room, making excavation work difficult and even posing a risk of the work room being submerged in water.

The purpose of this invention is to rectify the shortcomings of the conventional method for measuring the air pressure inside a box in a submersible box working room, and to easily correct the air pressure inside a box in a submersible working room appropriately in response to fluctuations in the groundwater level. The goal is to enable people to do what they do.

Hereinafter, preferred embodiments of the present invention will be described in detail based on the accompanying drawings.

FIG. 1 shows an outline of a conventional method for measuring the air pressure inside a box in a box working room in the air box construction method.

At the bottom of the submerged case body 1, there is a submerged case work chamber 2.
A shaft 4 is erected through the ceiling 3 of this subbox work room 2 for raising and lowering the excavated soil, materials, and personnel. A locking device 5 is installed for access.

Compressed air is supplied from an air compressor 6 installed on the ground through a pressure regulating valve 7, a main air pipe 8, a lock device 5, a shaft 4, and a submersible work room 2.
supplied to

The locking device 5 is also equipped with an air pressure gauge 9 that communicates with the box working chamber 2, and the compressed air supplied to the box working chamber 2 is regulated by a pressure regulating valve 7, and the air pressure inside the box is adjusted to the air pressure. This was confirmed using a pressure gauge 9.

As shown in FIG. 2, the method for measuring the air pressure inside a subcase according to the present invention is as follows: Above that, drive the well casing 12, and this casing 12
The inside of the well 13 is excavated to form a well 13, and the tip of the well 13 is filled with a filter material 14 to prevent the inflow of earth and sand. As a result, the groundwater reaches a height approximately equal to the groundwater table 15 of the ground 11.
It will ascend through Well 13.

Further, in the method of measuring the air pressure inside the box according to the present invention, a mechanical or electrical differential pressure gauge is used.

The structure of these differential pressure gauges is similar to conventional water level gauges that measure water depth.

As shown in FIG. 3, the mechanical differential pressure gauge is separated into a pressure receiving device 16 and an indicating device 17 which can be installed at an appropriate position on the ground.

This pressure receiving device 16 is surrounded by a housing 18 that is formed watertight on the outside.
The interior thereof is partitioned into an air chamber 20 and a water pressure chamber 21 by a partition wall 19.

A water introduction hole 22 for introducing water outside the housing 18 into the water pressure chamber 21 is provided in a water pressure chamber portion of the housing 18 that forms the water pressure chamber 21 .

An opening 23 is provided approximately in the center of the partition wall 19, and a pressure receiving bellows 24 is attached to the partition wall 19 so as to close this opening 23 to the water pressure chamber 21. The pressure-receiving bellows 24 is arranged to receive water pressure outside the pressure-receiving bellows 24 .

Further, an air pipe 25 is communicated with the air chamber 20 , air is introduced into the air chamber 20 through the air pipe 25 , and the pressure of the air introduced into the air chamber 20 is transferred to the inside of the pressure receiving bellows 24 . be done.

In this air chamber 20, two other transmitting bellows 26, 26' are arranged facing each other, and pedestals 27, 27' are fixed to the inner wall of the air chamber portion of the housing 18 forming the air chamber 20. is attached to.

The movable end 2 of this transmitting bellows 26, 26'
8, 28' and the movable end 29 of the pressure receiving bellows 24 are connected by a first connecting rod 30 and arms 31, 31' fixed to this connecting rod 30.

Further, one end of the transmission pipe 32, 32' communicates with the transmission bellows 26, 26', respectively, and the other end of the transmission pipe 32, 32' extends to the indicating device 17.

The indicating device 17 includes receiving bellows 33, 3.
3' are arranged opposite to each other and are fixedly attached at one end within the casing 34 of the indicating device 17.

Furthermore, the movable ends 35, 35' of the receiving bellows 33, 33' are connected by a second connecting rod 36, and the transmission pipes 32, 35' extended to the indicating device 17
2' communicate with receiving bellows 33, 33', respectively.

These transmitting bellows 26, 26' and transmission pipe 3
2, 32' and the receiving bellows 33, 33' are filled with liquid as an incompressible medium, mainly water. If there is a difference in the pressure of the air, the movable end 2 of the pressure receiving bellows 24
9 is displaced upward or downward, and the transmission bellows 2 is moved by the first connecting rod 30 and arms 31, 31'.
6, 26' is shortened and the other is lengthened.

By this operation, the incompressible medium enclosed in the respective systems passes through the transmission pipes 32, 32',
One of the receiving bellows 33, 33' is extended and the other is shortened.

Therefore, this receiving bellows 33, 33'
The second connecting rod 3 connected to the movable ends 35, 35' of
6 will operate left or right.

A link device 37 is connected to this second linking rod 36, and this operation is further transmitted to a gear 38 that interlocks with the link device 37 and a pinion 39 that meshes with this gear 38, causing the pinion 39 to rotate.

A pointer 40 is integrally attached to the pinion 39, and rotation of the pinion 39 causes the pointer 40 to
rotates to the left or right.

In this way, this differential pressure gauge uses the pressure receiving device 16 to detect the differential pressure generated between the inside and outside of the pressure receiving bellows 24 through the pointer 4.
0 and read the rotational position of the pointer 40 on the scale 41 to measure the differential pressure.

For example, when the water pressure is higher and the atmospheric pressure is lower, the pointer 40 rotates to the right (+ side), and when the atmospheric pressure is higher and the water pressure is lower, the pointer 40 moves to the left (- side). When the pointer 40 rotates and the water pressure and atmospheric pressure are balanced, the pointer 40 is adjusted to indicate the zero point.

Further, as the differential pressure gauge, an electrical differential pressure gauge that measures electrically can also be used.

This electrical differential pressure gauge is also separated into a pressure receiving device 16 and an indicating device 17, as shown in FIG.

This pressure receiving device 16 is surrounded by a housing 18 that is formed watertight on the outside.
The interior thereof is partitioned into an air chamber 20, a cavity 44, and a water pressure chamber 21 by an upper partition wall 42 and a lower partition wall 43.

A water introduction hole 22 for introducing water outside the housing 18 into the water pressure chamber 21 is provided in a water pressure chamber portion of the housing 18 that forms the water pressure chamber 21 .

Further, an air pipe 25 is communicated with the air chamber 20,
Air can be introduced into the air chamber 20 through the air pipe 25.

An opening 45 is provided approximately in the center of the lower partition wall 43, and a pressure receiving bellows 46 is attached to the lower partition wall 43 so as to close this opening 45, and is introduced into the water pressure chamber 21. The pressure receiving bellows 46 is arranged so as to receive the pressure of the water on the outside of the pressure receiving bellows 46.

Further, an opening 4 is also provided at approximately the center of the upper partition wall 42.
7 is provided in the air chamber 20, and this opening 47
Another pressure-receiving bellows 48 is attached to the upper partition wall 42 so as to close the air chamber 20, and is arranged to receive the pressure of the air supplied to the air chamber 20 on the outside of this pressure-receiving bellows 48.

The respective movable ends 49 and 50 of the respective pressure receiving bellows 46 and 48 are connected by a third connecting rod 51 made of a non-magnetic material.

Further, a coil portion 53 of a differential transformer 52 is fixed in the space 44, the third connecting rod 51 passes through the inside of the coil portion 53, and an iron core 54 is attached to the third connecting rod 51. , this iron core 54 stays in the coil part 53, and the third connecting rod 51 is displaced by the expansion and contraction of the pressure receiving bellows 46, 48, and the iron core 54
is a structure that can be moved up and down.

Cables 55 are pulled out from the primary and secondary sides of the coil portion 53 of the differential transformer 52, respectively.
It is extended to the indicating device 17 and wired to the following equipment to form a primary side circuit and a secondary side circuit.

The primary side circuit includes an AC power supply connection terminal 56, a DC stabilizer 57, and a high frequency oscillator 58.

The secondary circuit also includes an input circuit 59 that adjusts the zero point of the differential transformer 52, corrects errors due to line capacitance of the cable 55 between the differential transformer 52 and the indicating device 17, and has an output increase and impedance exchange function. An AC amplifying circuit 60 with an AC output, an AC/DC converter 61 for phase-discriminating and rectifying an AC output, a filter circuit 62 for removing ripples, and an indicator 63 are incorporated.

Introducing water into the water pressure chamber 21 of this electrical differential pressure gauge,
While introducing air into the air chamber 20, an AC power source 64 is connected to the AC power connection terminal 56 of the indicating device 17.

In this case, if there is a difference between the water pressure of the water introduced into the water pressure chamber 21 and the air pressure of the air introduced into the air chamber 20, each pressure receiving bellows 46, 48
Since they are connected by a connecting rod 51, one of the respective pressure receiving bellows 46, 48 is shortened, the other is expanded, and the third connecting rod 51 is displaced.

Therefore, the iron core 54 attached to the third connecting rod 51 is displaced upward or downward within the coil portion 53.

On the other hand, an AC power supply 64 connected to the instruction device 17
is converted into a high frequency constant voltage by the primary side circuit of the indicating device 17, and the primary side of the coil section 53 is excited, an alternating current magnetic flux with the iron core 54 as the main part of the magnetic circuit is generated, and the coil section 53 An alternating current voltage is induced on the secondary side of. In this case, the induced AC voltage changes due to the displacement of the iron core 54 within the coil portion 53. This is transmitted as an output to the indicator 17 via the cable 55, amplified and rectified by the secondary side circuit of the indicator 17, and shown on the indicator 63. By reading this, the differential pressure is measured.

These mechanical or electrical differential pressure gauges have the structure and function as described above, and have an air pipe 25 whose one end communicates with the air chamber 20 of the pressure receiving device 16 of these mechanical or electrical differential pressure gauges. The other end is communicated with the submersible box work chamber 2 which is being submerged.

As shown in FIG.
Even if the other end of the air pipe 25 is attached to the air pipe 25, communication with the work chamber 2 is possible.

In addition, the pressure receiving device 16 of the differential pressure gauge and the transmission pipes 32, 3
The indicating device 17 connected by 2' or cable 55 is placed at an appropriate location on land.

On the other hand, in the case work, the depth of the cutting edge 10 in the case work chamber 2 is always confirmed by surveying.

Next, the pressure receiving device 16 is suspended in the groundwater in the well 13 by a hanging cable 65 attached at one end to the upper end of the housing 18 of the pressure receiving device 16. The movable ends 29 of the pressure receiving bellows 24, 46 of the 16 water pressure chambers 21,
The other end of the hanging rope 65 is fixed to a stopper 68 provided on the ground so that the lengths of the ropes 49 and 49 are the same depth.

In this case, the movable end 2 of the pressure receiving bellows 24, 46
Verification of the depth of 9 and 49 is possible by attaching measuring scales to the hanging cable 65, etc.

By the above method, the air in the working chamber 2 is introduced into the air chamber 20 of the pressure receiving device 16 through the air pipe 25, and pushes the pressure receiving bellows 24 (the pressure receiving bellows 48 in the case of FIG. 4) downward. There is.

On the other hand, groundwater having a water pressure equal to the water level of the groundwater at the cutting edge 10 of the submersible work chamber 2 is introduced into the water pressure chamber 21 of the pressure receiving device 16 suspended in the groundwater in the well 13, and the pressure receiving bellows 24 [fourth In the case of the figure, the pressure receiving bellows 46] is pressed upward.

In addition, instead of the pressure receiving bellows 24, 46, 48,
It is clear that diaphragms fitted in openings 23, 45, 47 may also be used.

If there is a difference between the pressure inside the box introduced into the air chamber 20 and the water pressure of the groundwater in the well 13 introduced into the water pressure chamber 21, this pressure difference will be The pressure is transmitted from the pressure receiving device 16 to the indicating device 17 through the cable 55, and is displayed on the indicator 41 (indicator 63 in the case of FIG. 4).

A gauge man constantly monitors and operates the pressure regulating valve 7 installed in the main air pipe 8 so that this differential pressure display becomes an equal pressure display (zero point). The air pressure inside the box is regulated by controlling the compressed air inside the box.

For example, if the pressure inside the box is displayed as low (on the + side), if you operate the pressure regulating valve 7 to increase the pressure inside the box, the indicators 41 and 63 will display equal pressure (zero point). to move to.

In this case, the pressure of the air introduced into the air chamber 20 from the subcase work chamber 2 and the water pressure of the groundwater introduced into the water pressure chamber 21 are shown to be equal.

That is, since the water pressure of the groundwater in the well 13 introduced into the water pressure chamber 21 and the water pressure of the groundwater at the cutting edge 10 of the submersible work chamber 2 are almost equal, the pressure regulating valve 7
When the indicators 41 and 63 are operated to shift the display to the equal pressure display (zero point), the air pressure inside the box is more accurately balanced with the groundwater level at the cutting edge 10.

In this way, as the subcase body 1 sinks,
By lowering the pressure receiving device 16 in the well 13 according to the depth of the cutting edge 10, an index for setting the appropriate pressure inside the box at that position can be obtained, and by performing the same operation, The air pressure inside the box can be regulated.

Moreover, when the air pressure inside the box is to be balanced with the groundwater level at any position other than the cutting edge 10, the pressure receiving device 16 in the well 13 is positioned at that depth and the same operation is performed.

Further, according to this method, the pressure regulating valve 7 for compressed air supplied to the work chamber 2 is operated by other power, and the pressure of the incompressible medium transmitted from the pressure receiving device 16 to the indicating device 17 is Alternatively, it is also possible to extract the induced power as an output and control the pressure regulating valve 7 by a transmission device 66 such as a conventionally known electric/hydraulic servo mechanism to automatically set the air pressure inside the box.

In addition, a filter device 6 is installed in the air pipe 25 system that leads from the box work chamber 2 to the air chamber 20 of the pressure receiving device 16.
By providing 7, rapid pressure fluctuations within the subcase work chamber during subcase work are removed and transmitted to the pressure receiving device 16, allowing stable differential pressure measurement.

Conventional methods of measuring the atmospheric pressure inside the can include artificially calculating or measuring the groundwater level, assuming a corresponding atmospheric pressure, and then checking whether the internal pressure of the submersible has reached this atmospheric pressure.

Therefore, there is no indicator that can be used as an indicator for changes in the groundwater level due to tide levels, etc., and it is necessary to recalculate or measure it again. Nakatsuta.

However, in the method of the present invention, as the groundwater level in the well 13 changes as the groundwater level changes, the water pressure acting on the pressure receiving device 16 in the well 13 of the differential pressure gauge changes, and the differential pressure gauge immediately changes. indicator 41,
63 is displayed as a differential pressure display [(+) or (-)]. Using this as an indicator, simply operate the air pressure regulating valve 7 to return to the equal pressure display (zero point), and the groundwater will be detected midway through fluctuations. , the pressure inside the box can be immediately set to correspond to this.

Furthermore, in the conventional method of measuring the air pressure inside the box, the air pressure inside the box is compared with the atmospheric pressure, and the differential pressure is measured. For this reason, the pressure gauge used has a structure that is relatively resistant to high pressure, and its characteristics make it impossible to measure with high sensitivity.

Therefore, to be on the safe side, the pressure inside the box was set higher than the relevant groundwater level. As a result, the air pressure inside the box often goes around the cutting edge 10 and blows to the ground surface.

However, in the method of the present invention, the differential pressure gauge is used while the pressure receiving device 16 is balanced with groundwater having approximately the same pressure as the pressure inside the box, so the differential pressure is relatively small and both the pressure receiving device 16 and the indicating device 17 of the differential pressure gauge are used. The structure can be made to allow sensitive differential pressure measurements.

For example, the air pressure gauge 9 used in conventional submersibles could not obtain a water column of 10 cm to 20 cm. Numerical values can also be measured, and the pressure inside the box can be set to be completely equal to the groundwater level at the cutting edge 10 of the subcase.

As a result, the amount of air inside the box that goes around the cutting edge 10 and blows to the ground surface is reduced, thereby reducing the overall air consumption in the box work.

In addition, the air pressure inside the box and the water pressure of the groundwater in well 13 are
It is possible to read the differential pressure and equal pressure by measuring with different barometers and water level gauges, but due to the differences in the characteristics of the instruments, it is difficult to measure minute differential pressures or equal pressures using two instruments. There are many errors and the reliability is low.

It is clear that this method for measuring the pressure inside the box can also be applied to measuring the pressure inside the tunnel in tunnel construction in which subterranean water is excavated almost horizontally in the ground, for example, in the pressurized air shield method.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an overview of the conventional method for measuring the air pressure inside a box work room in the air submersible box construction method, Fig. 2 is an explanatory diagram showing an outline of the method of the present invention, and Fig. 3 is an explanatory diagram showing the outline of the method of the present invention. FIG. 4 is an explanatory diagram showing a partial cross-section of a mechanical differential pressure gauge used in the method of the present invention, and FIG. 1... Subbox body, 2... Subbox work room, 10...
Blade edge, 11... Ground, 13... Well, 15... Groundwater table, 16... Pressure receiving device, 17... Indicating device.

Claims (1)

[Scope of Claims] 1 (a) Outside of the main body of the submerged case that is being sunk in the ground, a well capable of raising groundwater to a height approximately equal to the groundwater level of the ground is constructed during submergence work of the main body of the submerged case that is being sunk. (b) The pressure receiving device of the differential pressure gauge is formed in the well so that the pressure receiving device of the differential pressure gauge occupies the same depth position in the well as the predetermined position of the subcase working chamber of the subcase main body. (c) transmitting to the pressure receiving device the water pressure in the well corresponding to the water pressure that changes due to fluctuations in the underground water level at a predetermined location in the box work chamber and the air pressure inside the box at the predetermined location; In addition, (d) the pressure receiving device is actuated by the pressure difference between the water pressure in the well and the pressure inside the box, and (e) the pressure receiving device is actuated to actuate the indicating device of the differential pressure gauge and the pressure difference is A method for measuring the air pressure inside a box in a submersible box working room, which consists of: indicating the pressure; 2. The method for measuring the air pressure inside a box in a box working chamber according to claim 1, wherein a cutting edge is selected as a predetermined location in the box working chamber, and a mechanical differential pressure gauge or an electrical differential pressure gauge is used as the differential pressure gauge.