JP4024504B2 - Method for measuring mud soil plastic fluidization and shield machine equipped with the plastic fluidization measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for measuring plastic fluidization of mud in a chamber in mud pressure shield drilling management, and a shield machine provided with this plastic fluidization measuring device.
[0002]
[Prior art]
One of the elements necessary for stable management of the mud pressure shield face is management of plastic fluidization of mud in the chamber of the shield machine.
[0003]
Conventionally, the management of plastic fluidization of mud in the chamber has been performed by property judgment based on experience of engineers, sampling investigation from a screw conveyor, and judgment by cutter torque.
[0004]
[Problems to be solved by the invention]
The property determination based on the experience of the former engineer is performed at the time when the material is discharged from a discharge device such as a screw conveyor, and thus cannot be grasped in real time. Moreover, since it depends on the judgment of the individual engineer, there is a problem that the evaluation varies.
[0005]
The sampling survey from the latter screw conveyor has a problem that the property of the mud in the chamber cannot be managed in real time because the degree of plastic fluidization is confirmed by visual observation, a slump test, a water content ratio test or the like.
[0006]
In addition, when judging from the cutter torque, in addition to the resistance torque due to the stirring blade, it includes torque due to soil cutting resistance, resistance due to friction between the cutter head and the soil, etc., and grasps only the stirring resistance of the mud in the chamber. There was a problem that it was difficult.
[0007]
The present invention has been made in view of the above points, and an object of the present invention is to provide a mud plastic fluidization measurement method capable of grasping in real time the degree of mud plastic fluidization in a chamber.
[0008]
Another object of the present invention is to provide a shield machine equipped with a plastic fluidization measuring device capable of grasping in real time the degree of plastic fluidization of mud in a chamber.
[0009]
It is another object of the present invention to provide a shield machine equipped with a plastic fluidization measurement facility capable of easily and safely performing maintenance of the mud clay plastic fluidization measurement device.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, in the method of the present invention, a method for measuring the plastic fluidity of mud created by excavating a natural ground with a mud pressure shield cutter, taking the excavated soil into the chamber, and kneading it with the mud material. , A rotary blade 20 is fixed to the tip of a rotary shaft 18 projecting from the partition wall into the chamber at a position away from the cutter drive shaft and the mixing blade on the partition wall 2 defining the chamber 6 in the front of the shield. the rotating body 19 is prepared Te, the arranged rotary body 19 at a position kneading blade does not pass the, or stopped in the shield, the times rotary body 19 provided on the captured chamber 6 mud 11 The rotational torque of the mud 11 is measured by rotation, and the plastic fluidization of the mud in the chamber 6 is determined based on the measured rotational torque.
[0011]
Moreover, the determination of the plastic flow of the mud chamber, a rotation torque measured, soil of mud collected in the chamber, earth pressure, density, water content ratio, the cutter torque, screw conveyor torque, visual information and sampling mud Rigyo are way Nau by the selected information from the survey results.
[0012]
The apparatus of the present invention is a plastic fluidization measuring device that measures the plastic fluidity of mud created by excavating natural ground with a mud pressure shield cutter, taking the excavated soil into the chamber, and mixing it with the mud material. In the shield machine provided, on the partition wall 2 partitioning the chamber 6 in the front of the shield, the rotary shaft 18 protrudes from the partition wall into the chamber at a position away from the drive shaft of the cutter and the mixing blade. made of a rotor blade 20 which is fixed, plastic flow consisting of a rotating rotary body 19 that measure the rotation torque of the mud 11 is rotated in the mud, a drive device for rotating the rotating body 19 by driving the rotary shaft 18 It is characterized by having a measuring device 15 .
[0013]
Further, the shield machine encloses the RI density / moisture meter line source 25 inside the rotating body 19 and measures the density and moisture content of the mud in addition to the rotational torque , and the soil quality and earth pressure of the mud in the chamber 6. And a sensor for detecting cutter torque and screw conveyor torque .
[0014]
Furthermore, in the shield machine of the present invention, the bulkhead 2 has a door 28 for the plastic fluidization measuring device, a gate 29 that can be opened and closed on the rear side of the bulkhead, and a storage box 31 that can accommodate the entire plastic fluidization measuring device 15. the door is provided, along with housing a 塑 fluidizing measuring device 15 to the storage box 31, a position housed in plastic flow of the measuring device 15 and a position that advances in the chamber 6 accommodating box 31 in retract and box 31 installed movably between, to retract and box 31, established a telescopic jack 33 for advancing and retracting operation of the plastic flow of the measuring device 15, thereby achieving the ease of maintenance.
[0015]
In addition, the rotary shaft 18 is provided with a jet nozzle 34 through which water or air that removes mud mud that adheres to and solidifies on the rotating portion can be ejected in the length direction of the rotating portion so that highly accurate measurement can be performed at all times. Yes.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0017]
[Example 1]
1 to 5 show a first embodiment of the present invention. FIG. 1 is a side view showing a basic configuration of a device for measuring plastic fluidization of mud in a chamber in mud pressure shield excavation management, and FIG. 2 is a diagram showing the same plastic fluidization. FIG. 3 is a front view of the main part showing the use state of the mud pressure shield having the measuring device, FIG. 3 is a front view of FIG. 2, and FIG. 4 is an overall configuration example of the use state of the mud pressure shield having the plastic fluidization measuring device, FIG. 5 is a flowchart showing a plastic fluidization measurement method performed using the plastic fluidization measurement apparatus.
[0018]
In Example 1 shown in these drawings, first, as shown in FIGS. 2 to 4, the mud pressure shield 1 includes a partition wall 2 provided in the front of the shield tube, a cutter 3 having a mixing blade 4, A cutter rotation driving device 5, a mud clay material injection means (not shown), a chamber 6, a screw conveyor 7 as a soil removal device, a shield jack 8 and the like are provided.
[0019]
Then, the mud pressure shield 1 is introduced from the starting shaft 9 shown in FIG. 4, the ground 10 is excavated by the cutter 3 of the mud pressure shield 1, the excavated soil is taken into the chamber 6, and the excavated soil is used as necessary. The mud material is injected by the mud material injection means and is kneaded by the kneading blade 4 provided in the cutter 3 to create the mud 11 having plastic fluidity.
[0020]
While preventing the face from collapsing due to the mud pressure in the chamber 6, the mud soil 11 in the chamber 6 is taken out by the screw conveyor 7 along with the excavation, carried out behind the mud pressure shield 1 and discharged.
[0021]
Further, the segment 12 is assembled in the rear of the mud pressure shield 1 and the mud pressure shield 1 is dug by taking a reaction force on the segment 12 by the shield jack 8.
[0022]
Repeat the above work to excavate the tunnel.
[0023]
In addition, as shown in FIG. 4, the operation control room 13 is installed behind the mud pressure shield 1, and the central monitoring room 14 is installed on the ground.
[0024]
By the way, this mud pressure shield 1 is provided with a housing 16, a rotating shaft 18, a rotating body 19 for measuring rotational torque, and a rotational driving device for the rotating body as shown in FIG. 1. A measuring device 15 is provided.
[0025]
That is, the housing 16 is fixed to the partition wall 2 of the mud pressure shield 1 as shown in FIGS.
[0026]
The rotating shaft 18 is supported by a bearing portion provided in the housing 16 and a bearing 17 provided in the partition wall 2.
[0027]
The rotating body 19 is for measuring the rotational torque, and has at least one appropriate number of rotating blades 20 extending in the diameter direction. The rotating body 19 is attached to the tip of the rotating shaft 18 and is installed in the chamber 6 of the mud pressure shield 1. In addition, when the rotational shaft 18 itself can measure rotational torque, it is not necessary to equip the rotary blade 20, and the rotational shaft 18 becomes a rotating body.
[0028]
The rotational drive device includes a motor 21, a pinion 22 attached to the motor 21, and a gear 23 attached to the rotary shaft 18 and meshed with the pinion 22. The motor 21 of this rotary drive device is configured to rotate the rotating body 19 reversibly and further to adjust the rotation speed.
[0029]
As shown in FIGS. 2 to 4, at least two mud clay plastic fluidization measuring devices 15 configured as described above are installed. The number and installation position are appropriately determined according to the size of the mud pressure shield. Each plastic fluidization measuring device 15 is connected to a computer installed in the operation control room 13 or the central monitoring room 14 through the cable 24, and is configured to process the captured information.
[0030]
Next, an example of a plastic fluidization measuring method using the plastic fluidization measuring device 15 will be described.
[0031]
While the shield is being dug or stopped, the rotating body 19 of the plastic fluidization measuring device 15 is rotated in the mud 11 in the chamber 6 and its rotational torque is measured.
[0032]
The state of plastic fluidization of mud can be known by whether or not the rotational torque is within an appropriate range according to the soil quality.
[0033]
That is, the appropriate value range of the rotational torque according to the soil refers to a state in which the mud exhibits hardness and properties in the range of the slump value SL = 5 cm to 15 cm. By keeping the properties of the mud within this range, stable shield digging can be secured. Outside the range, various troubles often occur.
[0034]
For example, when SL = 5 cm or less, mud is in a state of being easily fixed, and may be blocked by a chamber or a screw conveyor of a soil removal device. Also, as SL becomes 15 cm or more, mud increases fluidity and the screw conveyor's demounting effect becomes poor. When the soil water pressure at the face is high, the mud may erupt from the screw conveyor.
[0035]
In the present invention, if the mud is within the range of torque corresponding to the hardness and property of slump value SL = 5 cm to 15 cm, it is determined that the plastic fluidization of mud is generally good.
[0036]
In the determination, the measured value of the rotational torque is sent to a computer in the operation control room 13 or the central monitoring room 14, and is determined and controlled by a known computer processing technique.
[0037]
At the same time, various other information on the mud 11 in the chamber 6 is separately detected by using various known sensors and the information is sent to a computer to make a comprehensively accurate determination of plastic fluidization. It can also be done. The mud soil information includes, for example, soil quality, chamber earth pressure, mud 11 density, moisture content, cutter torque, screw conveyor torque, and the mud 11 in the chamber such as visual inspection and sampling survey of the mud 11 by an operator. Information. If all of these pieces of information are obtained and a determination is made, a highly accurate determination can be made. However, if necessary, the determination may be made by selectively fetching any one of them.
[0038]
As a result of the determination, when it is determined that the mud 11 in the chamber 6 is sufficiently plasticized, the current excavation state is maintained.
[0039]
On the contrary, when it is determined that the mud 11 in the chamber 6 is not sufficiently plasticized, the amount of the mud material injected is increased or decreased, and the determination is performed again.
[0040]
If it is determined that the plastic fluidization of the mud 11 in the chamber 6 has not yet been sufficiently achieved even if the amount of mud mud material injected is increased or decreased, the blending amount of the mud clay material composed of bentonite, water, etc. Are reconsidered, adjusted and supplied, and management is performed so that the plastic fluidization of the mud 11 becomes appropriate.
[0041]
As described above, according to the first embodiment, the rotational torque is independently measured by the rotating body 19 of the plastic fluidization measuring device 15 provided in the chamber 6 instead of using the cutter torque as in the prior art. Therefore, since only the resistance torque of the mud 11 in the chamber 6 can be grasped, it is possible to surely know the degree of plastic fluidization of the mud. In the case of a shield for excavating a large cross section, it is possible to accurately grasp the properties of mud throughout the entire area of the chamber 6 by installing a large number of plastic fluidization devices 15.
[0042]
Further, according to the first embodiment, since the property of the mud 11 in the chamber 6 can be grasped in real time from the measured value of the rotational torque by the rotating body 19, the excess or insufficient amount of the mud material injection is prevented, and the plastic fluidization is achieved. Sufficiently planned mud 11 can be held, and therefore stable shield excavation management can be performed.
[0043]
[Example 2]
Next, FIG. 6 is a longitudinal side view showing Example 2 of the present invention.
[0044]
In the second embodiment shown in FIG. 6, an RI density / moisture meter source 25 for detecting information on the density or water content of the mud is enclosed at the inner tip of the rotor blade 20 of the rotor 19 of the plastic fluidization measuring device 15. It has the feature.
[0045]
Further, a RI measurement detection device 26 for detecting and judging the replacement time and calibration time of the RI density / moisture meter line source 25 is attached to a substantially central portion of the partition wall 2 which is a fixing member in the mud pressure shield 1. .
[0046]
Therefore, according to the second embodiment, the determination of plastic fluidization of the mud 11 in the chamber 6 can be performed more accurately.
[0047]
Other configurations and operations in the second embodiment are the same as those in the first embodiment.
[0048]
[Example 3]
7 to 10 show a third embodiment of the present invention. FIG. 7 is a longitudinal side view of the plastic fluidization measuring device in use, FIG. 8 is a front view of FIG. 7, and FIG. FIG. 10 is a front view of FIG. 9.
[0049]
In the third embodiment shown in FIGS. 7 to 10, the plastic fluidization measuring equipment 27 is provided in the partition wall 2 with an entrance / exit 28 for the plastic fluidization measuring device, a rotary gate 29 which is an openable / closable gate, and a plastic fluidizing device. When the removal of the mud solidified on the rotary body 19 and the replacement and calibration of the RI density / moisture meter line source 25 are necessary, the entire plastic fluidizing device 15 is separated from the partition wall 2. It has a feature that it can be housed inside, and has improved maintenance workability.
[0050]
That is, the rotary gate 29 is formed in a substantially semicircular shape and has a set of two gate plates that are combined in a circular shape. The gate plate is arranged on the chamber 6 side of the partition wall 2 and is opened and closed by rotating it through a hinge 30 provided at the upper part of the entrance / exit 28.
[0051]
The storage box 31 is fixed to the inner side of the partition wall 2. On the partition 2 side of the storage box 31, a door 32 that opens upward from the horizontal state is provided. Inside the storage box 31, the plastic fluidization measuring device 15 shown in the second embodiment is installed so as to be movable forward and backward with respect to the chamber 6.
[0052]
In the storage box 31, an expansion / contraction jack 33 for advancing and retracting the plastic fluidization measuring device 15 is installed.
[0053]
In this plastic fluidization measuring equipment 27, when using the plastic fluidization measuring device 15, as shown in FIGS. 7 and 8, the rotary gate 29 is opened and the plastic fluidization measuring device 15 is rotated by the extension jack 33. The body 19 is advanced so as to be placed in the chamber 6.
[0054]
Then, the plastic fluidization measuring device 15 is pulled into the machine as necessary, for example, when removing the mud solidified on the rotating body 19 or exchanging and calibrating the RI density / moisture meter source 25 enclosed in the rotating body 19. At that time, as shown in FIGS. 9 and 10, the entire plastic fluidization measuring device 15 is drawn into the storage box 31 by the telescopic jack 33 and stored.
[0055]
Thereafter, the rotary gate 29 is closed to prevent mud from entering the machine through the doorway 28.
[0056]
Next, the door 32 provided in the storage box 31 is opened, and operations such as removal of mud solidified on the rotating body 19 and replacement and calibration of the RI density / moisture meter source 25 are performed.
[0057]
When the plastic fluidization measuring device 15 is returned to the use state after the above-described operation is finished, the door 32 is closed, the rotary gate 29 is opened, and the plastic fluidization measuring device 15 is pushed out toward the chamber 6 by the extension jack 33. The rotating body 19 of the plastic fluidization measuring device 15 is arranged in the chamber 6.
[0058]
As can be seen from the above description, according to the third embodiment, removal of mud solidified on the rotating body 19, replacement and calibration of the RI density / moisture meter line source 25 enclosed in the rotating body 19, etc. At this time, since the entire plastic fluidization measuring device 15 can be drawn into the storage box 31, the operation can be performed easily and safely.
[0059]
Of course, the plastic fluidization measuring device 15 shown in the first embodiment may be stored in the storage box 31.
[0060]
Further, the gate may be a slide type instead of the rotary type. Furthermore, the gate may be provided not only on the chamber 6 side of the partition wall 2 but on the inside of the apparatus.
[0061]
Further, the door 32 is not limited to the illustrated embodiment provided in the upper part of the storage box 31, and may be provided in the side part, the rear part, or in the lower part.
[0062]
Furthermore, any surface of the storage box 31 may be configured to be removable so that the entire plastic fluidization measuring device 15 can be taken out from the storage box 31.
[0063]
[Example 4]
FIG. 11 shows Example 4 of the present invention and is an enlarged front view of a plastic fluidization measuring apparatus.
[0064]
In the fourth embodiment shown in FIG. 11, when a plurality of jet injection ports 34 are provided in the vicinity of the rotary body 19 on the rotary shaft 18 of the plastic fluidization measuring device 15 and mud soil is consolidated on the rotary body 19, It is characterized in that mud soil adhering to and solidifying the rotating body 19 can be easily and quickly removed by ejecting water or air from the mouth 34.
[0065]
That is, the rotary shaft 18 is provided with a passage (not shown) for air or cleaning liquid that passes from the inner end of the machine through the inside of the rotary shaft 18 to the jet injection port 34. This passage is connected to air or cleaning liquid supply means (also not shown).
[0066]
Therefore, in the fourth embodiment, when removing the mud adhering to the rotating body 19 and solidifying, the air 35 or the cleaning liquid is sprayed from the jet injection port 34 toward the rotating body 19.
[0067]
Thereby, the mud adhered to the rotating body 19 and solidified can be easily removed, and an accurate measured value of the rotational torque can always be obtained by the rotating body 19.
[0068]
The fourth embodiment can be applied to the first to third embodiments.
[0069]
【The invention's effect】
As described above, according to the method of the present invention, during the shield excavation or stop, the rotating body 19 provided in the chamber 6 into which the mud is taken is rotated to measure the rotating torque, and the chamber 6 is measured based on the rotating torque. The determination of the plastic fluidization of the mud in the chamber 6 is performed, and only the resistance torque of the mud in the chamber 6 can be measured by the rotating body in the chamber 6, so that the degree of plastic fluidization of the mud in the chamber 6 is ensured. It has a measurable effect and can grasp the mud properties in the chamber 6 in real time.
[0070]
Further, in the method of the present invention, during the shield excavation or stop, the rotating body 19 provided in the chamber 6 into which the mud is taken is rotated to measure the rotating torque, and this rotating torque and the collected inside of the chamber 6 are measured. Since the determination of plastic fluidization of the mud in the chamber 6 is comprehensively performed based on the other information of the mud, the degree of plastic fluidization of the mud in the chamber 6 can be grasped more accurately. And can be managed.
[0071]
Further, according to the shield machine of the present invention, the rotary body 19 for measuring rotational torque is installed in the chamber 6 of the mud pressure shield, and this rotary body 19 is connected to the rotary drive device. Only the resistance torque of the mud can be measured easily and reliably with a simple configuration device.
[0072]
Furthermore, in the shield machine of the present invention, the RI density / moisture meter line source 25 is enclosed at the inner tip of the rotating body 19, and in addition to the measured value of the rotational torque by the rotating body 19, the RI density / moisture meter line source. 25, the water content ratio of the mud in the chamber 6 is also measured, so that the mud property in the chamber 6 can be more accurately determined.
[0073]
In the shield machine of the present invention, the partition wall 2 of the mud pressure shield is provided with an entrance / exit 28 for the plastic fluidization measuring device, an openable / closable gate 29, and a storage box 31 for the plastic fluidization measuring device. The plastic fluidization measuring device 15 is housed in a box 31, and the plastic fluidization measuring device 15 is installed in the housing box 31 so as to be movable back and forth with respect to the chamber 6. Since the 15 expansion / contraction jacks 33 for advancing and retreating are installed, there is an effect that the plastic fluidization measuring device 15 can be easily and safely performed such as cleaning, inspection, maintenance and adjustment.
[0074]
Furthermore, even if mud adheres to and solidifies on the rotating portion for measurement, the jet injection port 34 is provided on the rotating shaft 18, so that it can be easily and quickly removed, and measurement with high accuracy can always be performed.
[Brief description of the drawings]
FIG. 1 is a side view showing details of an apparatus for measuring plastic fluidization of mud in a chamber according to Embodiment 1 of the present invention.
FIG. 2 is a longitudinal side view showing a usage state of the plastic fluidization measuring apparatus shown in FIG.
FIG. 3 is a front view of FIG. 2;
4 is a system diagram of the plastic fluidization measuring apparatus shown in FIG.
FIG. 5 is a flowchart of a plastic fluidization measuring method performed using the plastic fluidization measuring apparatus shown in FIG.
FIG. 6 is a longitudinal side view showing Embodiment 2 of the present invention.
FIG. 7 shows a third embodiment of the present invention and is a longitudinal sectional side view of the plastic fluidization measuring device in use.
FIG. 8 is a front view of FIG. 7;
FIG. 9 is a longitudinal side view of the plastic fluidization measuring apparatus according to the third embodiment in a stored state.
10 is a front view of FIG. 9. FIG.
FIG. 11 is an enlarged front view showing Embodiment 4 of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Mud pressure shield 2 Bulkhead 3 Cutter 5 Cutter rotation drive device 6 Chamber 7 Screw conveyor 8 which is a soil removal device 8 Shield jack 10 Ground 11 Mud in the chamber 13 Operation control room 14 Central monitoring room 15 Plastic fluidization measuring device 16 Housing 18 Rotating shaft 19 Rotating body 20 for measuring rotational torque Rotating blades 21, 22, 23 Members constituting the rotational driving device for the rotating body 25 RI density / moisture meter source 26 RI measuring detector 27 Plastic fluidization Measuring equipment 28 Plastic fluidization measuring device doorway 29 Rotary gate 31 Storage box 32 for plastic fluidization measuring device Door 33 Telescopic jack 34 Jet injection port 35 Air

Claims (6)

In the method of measuring the plastic fluidity of mud created by excavating natural ground with a mud pressure shield cutter, taking the excavated soil into the chamber and mixing with the mud material,
A rotating blade (18) on the tip of a rotating shaft (18) protruding from the partition into the chamber at a position away from the cutter drive shaft and the mixing blade on the partition (2) partitioning the chamber (6) in the front of the shield. 20) is fixed and a rotating body (19) is prepared,
The rotating body (19) is arranged at a position where the kneading blade does not pass through,
During shield or stopped, mud (11) rotary body times provided captured within chamber (6) to (19) is rotated to measure the rotational torque of the mud (11),
A method for measuring plastic fluidization of mud characterized in that determination of plastic fluidization of mud in the chamber (6) is performed based on the measured rotational torque. Determination of plastic fluidization of the mud in the chamber (6), the measured rotational torque and the collected soil, earth pressure, density, water content, cutter torque, screw conveyor torque of the mud (11) in the chamber (6) , plastic flow of the measuring method of mud of claim 1, wherein the Nau Rigyo by the selected information from the visual information and sampling findings mud. In a shield machine equipped with a plastic fluidization measuring device that measures the plastic fluidity of mud created by excavating natural ground with a mud pressure shield cutter, taking the excavated soil into the chamber, and mixing with the mud material,
A rotating shaft (18) and a rotating shaft (18) projecting from the partition into the chamber at a position away from the cutter drive shaft and the mixing blade on the partition (2) partitioning the chamber (6) in the front of the shield made of a rotor blade which is fixed to the tip (20), and times you measure the rotational torque of the mud (11) is rotated in mud rotary body (19), the rotating body to drive the rotary shaft (18) A shield machine equipped with a plastic fluidization measuring device (15) comprising a plastic fluidization measuring device (15) comprising a drive device for rotating (19) . Inside the rotating body (19), an RI density / moisture meter source (25) is sealed, and in addition to the rotational torque , the density and water content of the mud are measured , and the soil mud soil, earth pressure, The shield machine provided with the plastic fluidization measuring device according to claim 3 provided with a sensor which detects cutter torque and screw conveyor torque . In the partition wall (2), a door (28) for the plastic fluidization measuring device, a gate (29) that can be opened and closed on the rear side of the partition wall, and a storage box (31) capable of storing the entire plastic fluidization measuring device (15 ). the door is provided, along with housing 塑 fluidizing measuring device (15) to the storage box (31) and plastically fluidized measuring device (15) advances into the chamber (6) in the retract and box (31) position and retractably installed between the storage box (31) housed in a position, in retract and box (31) in the telescopic jack for advancing and retracting operation of the plastic flow of the measuring device (15) (33) The shield machine provided with the plastic fluidization measuring apparatus according to claim 3 or 4, wherein the shield machine is installed. The jet shaft (34) capable of ejecting water or air for removing mud soil adhering to and solidifying the rotating portion in the length direction of the rotating portion is provided on the rotating shaft (18). shield machine having a plastic flow of the measurement device 4, or 5 Symbol mounting.

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