JP2923034B2 - How to shut off the tail seal of the shield machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for stopping a tail seal portion of a shield machine for excavating underground under a large depth and high water pressure.

[Conventional technology]

In shield excavators that excavate underground under large depths and high water pressures, maintaining the waterproofness of the tail seal is an important issue in order to ensure the safety of underground work. As a method for solving this problem, as described in JP-A-2-76096, a tail skin plate of the shield body is provided with a plurality of tail seals, and a chamber formed between the tail seal steps has fluidity. Filling the filler and maintaining the pressure of the filler at a pressure that can withstand the earth pressure and water pressure of the surrounding ground,
Experiments have shown that water leakage from the tail seal can be prevented even under a high water pressure of gf / cm ² or more.

7 and 8 show a state in which the tail seal portion according to the prior art is being dug. In these figures, the tail skin plate 1a of the shield body 1 is provided with two stages of tail seals 8 which are in contact with the outer periphery of the segment 9, and a filler injection pump (see FIG. (Not shown), a fluid filler (such as fiber-containing grease) is filled through the filler injecting pipe 12. As the shield body 1 is propelled, the filler filled in the chamber 10 adheres to the segment 9 and flows out toward the ground, so that the filler pressure in the chamber 10 gradually decreases.
The pressure of the filler in the chamber 10 is maintained at a pressure that can withstand the earth pressure and the water pressure of the surrounding ground by supplying the filler that has flowed out through the filler injection pipe 12.

However, the segment 9 is provided with a grout hole 9a which is open on the outer peripheral side thereof.
Even when 9b is mounted, a space remains between the plug end and the outer peripheral side of the segment. Moreover, in a state where the segments are assembled, the grout holes 9a of the respective segments constituting one ring are arranged in a line in the circumferential direction, so that the space volume of the grout hole for one ring becomes considerably large. Also, an opening groove that opens to the outer peripheral side at the segment joint
9c may be present. Therefore, as shown in FIGS. 7 and 8, recesses such as grout holes 9a and opening grooves 9c opened on the outer peripheral side of the segment with the propulsion of the shield main body 1 ride over the tail seal 8 on the face side and the tail seal step. As they enter the room 10 between them, these recesses
10 creates a large space, which causes the pressure of the filling material in the chamber 10 to drop sharply, making it impossible to withstand the earth pressure and water pressure of the surrounding ground, and water leaking into the machine through the tail seal until the filling pressure recovers. Occurs. In addition, the filling material is
In some cases, the pressure of the filler does not recover and water leakage does not stop. This is because the replenishment of the filler cannot keep up with the suddenly large space created in the chamber 10, and the instantaneous replenishment of the amount of the filler corresponding to the space volume is
It is not practical because the capacity of the filling material injection pump becomes enormous.

[Problems to be solved by the invention]

As described above, in the prior art, when a concave portion such as a grout hole or an aperture groove opened on the outer peripheral side of the segment passes over the tail seal on the face side and enters the chamber 10 between the tail seal steps, a suddenly large space is formed. Chamber 10 by arising
No consideration was given to the point that the pressure of the filler in the interior was reduced and the recovery was delayed, and it was found that water leakage from the tail seal portion due to pressure fluctuation of the filler could not be prevented.

In view of the above, the present invention provides a filling material in a room formed between a tail seal on the most ground side and a tail seal on the front stage due to disturbance of a recess such as a grout hole and an opening groove opened on the outer peripheral side of the segment. An object of the present invention is to prevent the stability of pressure from being disturbed, and to maintain the waterproofness of a tail seal portion under high water pressure.

[Means for solving the problem]

In order to achieve the above object, a method for stopping water at a tail seal portion according to the present invention is to equip a tail skin plate of a shield body with at least three stages of tail seals, and a first stage and a second stage tail seal and a segment from a face side. (Referred to as a first chamber) and a chamber (referred to as a second chamber) separated by a tail seal and a segment at the second and third stages, respectively, for filling a fluid filler. First and second filler supply means are provided, and the first filler supply means allows a recess, such as a grout hole or an aperture groove, which opens on the outer peripheral side of the segment as the shield body is propelled to pass through the first chamber. In the meantime, the filler is supplied to the first chamber so as to substantially fill the recesses with the filler, and the filler pressure in the second chamber is increased by the second filler supply means based on the measured ground pressure. Earth pressure of surrounding mountains, While maintaining the pressure can counter pressure, characterized in that replenishing the amount of filler that has flowed into the natural ground attached to the segment to the second chamber.

[Action]

In the above configuration, the first filler supply means fills almost all of the recesses with fillers while the recesses such as grout holes and aperture grooves opened on the outer peripheral side of the segment as the shield body is propelled pass through the first chamber. The first filler is supplied to the first chamber so that the second filler is supplied to the second chamber by the second filler supplying means. With this configuration, when the recesses such as the grout hole and the opening groove opened on the outer peripheral side of the segment enter the second chamber from the first chamber, the recesses are already almost filled with the filler, so that The pressure of the filler in the second chamber does not drop sharply, and the pressure of the filler in the second chamber is maintained at a pressure that can withstand the earth pressure and the water pressure (hereinafter referred to as the ground pressure) of the surrounding ground. it can. Further, even when the ground pressure changes or when the filler pressure in the first chamber decreases, the filler pressure in the second chamber is determined by the second filler supply means based on the measured ground pressure. While maintaining the pressure at a level that can withstand the earth pressure and water pressure of the surrounding ground, replenish the second chamber with the amount of the filler adhering to the segments and flowing out to the ground,
Since the ground pressure can be countered only by the pressure of the filler in the second chamber, it is possible to reliably prevent water leakage into the machine.

〔Example〕

 1 to 4 show an embodiment of the present invention.

1 to 3, 1 is a shield main body, 2 is a cutter wheel, 3 is a bulkhead, 4 is a face water pressure gauge, 5 is a screw conveyor for discharging, 6 is a motor for driving a cutter,
7 is a shield jack, 81,82,83 are tail seals, and 9 is a segment.

The number of the tail seals may be three or more. In this embodiment, three tail seals 81, 82, and 83 made of a brush seal mainly composed of a bundle of steel wires are provided on the tail skin plate 1a of the shield body 1. The first chamber 101 and the second and third-stage tail seals 82 and 83 and the segment 9 separate the chamber divided by the first and second-stage tail seals 81 and 82 and the segment 9 from the face side. The room thus created is referred to as a second room 102.

First and second filler supply means are provided to fill the first chamber 101 and the second chamber 102 with a filler having fluidity (such as fiber-containing grease). The first filler supplying means is a filler inlet of the tail skin plate 1a.
A filler injection pipe 121 connected to 111, a filler injection pump 131 installed in the machine, and an injection pump driving motor 14
1, a filler tank 151, and the second filler supply means is likewise a filler inlet 112 of the tail skin plate 1a.
Filler injection pipe 122 connected to the, filler injection pump 132 installed in the machine, injection pump drive motor 142,
It comprises a filler tank 152. 16 is tail skin plate 1
It is a protective cover for the injection pipes 121 and 122 laid on the outer periphery of a.

On the other hand, the first chamber 10
1. First and second measurement of each filler pressure in the second chamber 102
Pressure sensors 171,172 and tail skin plate 1a
A third pressure sensor 173 for measuring the ground pressure is installed at the rear end of the device, and the output signals of these pressure sensors 171, 172, 173 are led to a pressure transmitter 19 via a wiring 18, and the amplified signal is installed in the machine. The signal is transmitted to the infusion pump control device 21 via the wiring 20. Reference numeral 22 denotes a protective cover for the pressure sensors 171, 172, 173 and the wiring 18.

The infusion pump control device 21 receives the signal from the pressure transmitter 19 and the power supply 23, and starts and stops the infusion pump driving motors 141 and 142 connected by the wiring 24.

In the present embodiment, the filler layer thickness of the first chamber 101 (the mounting pitch dimension of the first-stage tail seal 81 and the second-stage tail seal 82) depends on the shield propulsion speed and the filler injection pump 131.
Is determined in consideration of the capacity of In other words, during the period from when the recesses on the outer surface of the segment, such as the grout holes 9a and the opening grooves 9c shown in FIG. Room 101
The thickness of the filler layer of the first chamber 101 is determined so that the space generated in the first chamber 101 can be substantially filled with the filler.

The thickness of the filler layer in the second chamber 102 (the second-stage tail seal 8
The mounting pitch dimension of the second and third stage tail seals 83)
By maintaining the pressure of the filler in the chamber 102 at a pressure that can counteract the ground pressure, the dimensions are such that water can be stopped only in the second chamber 102. In other words, if there are no factors that fluctuate the filler pressure, such as grout holes and aperture grooves,
It is configured so that water can be stopped without the first chamber 101.

In the present embodiment, the filler pressure in the first chamber 101 and the second chamber 102 is managed by turning on and off the filler injection pumps 131 and 132 with reference to the ground pressure measured by the pressure sensor 173.

The upper and lower limits of the filler pressure for maintaining the water stopping effect while minimizing the consumption of the filler are given by the following equations.

Pg ₁ = Pw + p ₁ …… (1) Pg ₂ = Pw + p ₂ …… (2) Pg ₁ : Upper limit of filler pressure Pg ₂ : Lower limit of filler pressure Pw: Ground pressure p ₁ : Tail seal on ground side Filler passage resistance between the wire and the segment p ₂ : Critical pressure difference at which water can be stopped Here, p ₁ and p ₂ are values determined by experiments and the like.

Assuming that the driver manually controls the supply and stop of the filler material, the driver may use pressure sensors 171, 172, 173.
When the filler pressure decreases and reaches the lower limit value Pg ₂ while monitoring the ground pressure measured in Step 1 and the filler pressure in the first chamber 101 and the second chamber 102, the filler injection pumps 131 and 132 are turned on to perform filling. start the injection of wood, it will stop the injection of the filling material by turning off the filler infusion pump 131 and 132 when fillers pressure has reached the upper limit value Pg ₁ rises.

Even in a normal state where there is no change in the volume of the first chamber 101 and the second chamber 102, the injected filler adheres to the segment and flows out to the ground G side, so that the filler of the first chamber 101 and the second chamber 102 The pressure is not abrupt, but gradually decreases. Experiments have shown that the amount of filler attached to the segment is about 200 cc per 1 m ² of the segment surface area.

Calculating the carry-out amount of the filler for a segment with an outer diameter of 14 m is as follows.

Q = πD (V / 100) ρ = 3.14 × 14 × (3/100) × 200 = 263 Q = Amount of filler taken out [cc / min] D = Segment outer diameter 14 [m] V = Shield propulsion speed 3 [ cm / min] ρ = filler adhesion amount 200 [cc / m ² ] This is an amount within a range that can be sufficiently handled by the capacity of a commercially available filler injection pump.

On the other hand, when the grout hole 9a passes through the tail seal portion, the filler pressure in the first chamber 101 and the second chamber 102 changes as shown in FIG. When the grout hole 9a enters the first chamber 101 over the first-stage tail seal 81, the pressure of the filler in the first chamber 101 is rapidly reduced due to the space created thereby. Therefore, the driver tries to increase the pressure by injecting the filler into the first chamber 101, but it takes time to fill the space by the grout hole 9a with the filler. However, even in this case, the filler is almost completely filled in the space of the grout hole 9a before the grout hole 9a enters the second chamber 102 over the second-stage tail seal 82, and the residual air is also filled with the filler. Since it has been compressed to the same pressure, it does not affect the filler pressure in the second chamber 102.

Calculation of the required injection amount of the filler so as not to affect the space volume generated by the grout hole and the pressure of the filler in the second chamber 102 for the segment having an outer diameter of 14 m is as follows.

^{Vj = (πd 2/4)} Ln = (3.14 × 6 2/4) × 50 × 11 = 15543 Vj: space volume produced by grout holes [cc] d: grout hole inner diameter 6 [cm] L: Grout hole length 50 [cm] n: Number of grout holes (for one ring) 11 [pieces] Qj = Vj / Tj = 15543 / 13.3 = 1168 Qj: Required injection amount of filler [cc / min] Tj: Filling time [min] ( (Time during which the grout hole passes through the first chamber) Tj = Lb / V = 40/3 = 13.3 Lb: Mounting pitch size of the first-stage tail seal and the second-stage tail seal 40 [cm] V: Shield propulsion speed 3 [ cm / min] As can be seen from the above calculation results, the filling material injection pump having a capacity of 1168 cc / min or more is replaced with the filling material injection pump 13 for the first chamber.
If equipped as 1, the pressure of the filler in the second chamber 102 is the lower limit Pg
_No lower than ₂ . In this case, it takes 13.3 minutes for the pressure in the first chamber 101 to recover, but during that time, the pressure of the filler in the second chamber 102 alone is sufficient to counter the ground pressure, and water leakage can be prevented.

Up to this point, the case where the driver manually controls the supply and stop of the filler is described. Next, the case where the supply and stop of the filler is automatically controlled using the infusion pump control device 21 of FIG. 1 will be described. I do. Fig. 4 shows an infusion pump controller
21 shows a configuration example.

The pressure setting unit 25 in the infusion pump control device 21 fills from the ground pressure Pw measured by the third pressure sensor 173 and the values p ₁ and p ₂ input in advance by the formulas (1) and (2). The upper limit Pg ₁ and lower limit Pg ₂ of the material pressure are calculated and set.

Fillers pressure in the first chamber 101 to the first pressure sensor 171 is measured, the upper limit value Pg ₁ in a comparator 26, are compared respectively with the lower limit value Pg ₂ by the comparator 27, by their judgment output, first Room 10
When the filler pressure of 1 decreases and reaches the lower limit value Pg ₂ , the motor control unit 30 starts the motor 141, and when the filler pressure of the first chamber 101 increases and reaches the upper limit value Pg ₁ , motor control is performed. The unit 30 stops the motor 141. Similarly, the filler pressure in the second chamber 102 measured by the second pressure sensor 172 is equal to the upper limit P
and g _1, is compared respectively with the lower limit value Pg ₂ by the comparator 29, by their judgment output, when the filling material pressure in the second chamber 102 reaches the lower limit value Pg ₂ decreases, the motor controller 31 the motor 142 Is activated, and the pressure of the filler in the second chamber 102 rises to the upper limit Pg ₁
, The motor control unit 31 stops the motor 142. The motor control units 30 and 31 have a self-holding function,
While the filler pressure changes from the lower limit to the upper limit, fill pump 13
The injection pumps 131 and 132 are kept stopped (off) while the filler pressure changes from the upper limit to the lower limit.

FIG. 6 is a diagram showing a control process in the case where the upper and lower limits of the filler pressure are set based on the measured value of the ground pressure as described above and the injection control of the filler is performed. That is, the second room 10
The filler pressure of 2 is always the upper limit Pg ₁ even if the ground pressure Pw changes
And maintained within the range between the lower limit value Pg _2, also if the grout holes or the like as the pressure fluctuation factor has entered the tail sealing portion, second only time pressure recovery in the first chamber 101 extends The pressure of the filler in the chamber 102 is not affected, and the water stopping effect can be maintained.

Although illustration is omitted, a target value (for example, a pressure value slightly higher than the ground pressure) of the filler pressure is set by a pressure setting unit in the injection pump control device based on the measured value of the ground pressure, The same object as described above can be achieved by a configuration in which the measured value of the filler pressure is compared with the target value and the filler injection amount of the injection pump is controlled so that they match.

Further, as another embodiment of the present invention, instead of controlling the filler pressure in both the first chamber and the second chamber, only the filler pressure in the second chamber is set to a pressure that can counteract the ground pressure. There is also a method in which the filler is supplied to the first chamber at a certain set flow rate by another injection pump. In this case, the driver determines the flow rate of the filling material injection pump in the first chamber by calculation,
During the excavation, the pump is kept operating to fill the space created by the grout hole or the like in the first chamber. In the meantime, the filler pressure in the first chamber is monitored, and if the filler pressure is too low or too high, the setting of the flow rate of the filler injection pump may be changed. FIG. 5 shows a configuration example of the injection pump control device for automatically controlling the pressure of the filler in the second chamber in the present embodiment. Since the configuration is basically the same as that shown in FIG. 4, the description is omitted.

In each of the above embodiments, two filler injection pumps are provided for the first chamber and the second chamber. However, when a commercially available filler injection pump does not have a sufficient flow rate, a plurality of filler injection pumps may be connected in parallel. Good. In addition, a large flow rate pump is adopted, and the first
The filler may be distributed and supplied to the chamber and the second chamber.

Regarding the pump capacity, the capacity of the filler injection pump for the first chamber is larger than the capacity of the filler injection pump for the second chamber in each embodiment. As described above, the amount of the filler for filling the grout hole or the like is larger than the amount of the filler adhering to the segment and flowing out to the ground.

〔The invention's effect〕

According to the present invention, when a concave portion such as a grout hole or an aperture groove opened on the outer peripheral side of the segment enters the tail seal portion, the filler is filled in the space created by the concave portion in the first chamber between the tail seal steps. It is almost filled and does not affect the pressure of the filler in the second chamber, thereby preventing water leakage from the tail seal portion due to pressure fluctuation of the filler,
The filler pressure in the second chamber is maintained at a pressure that can withstand the earth pressure and the water pressure of the surrounding ground, based on the measured ground pressure, and adheres to the segment to form the ground. The amount of the filler that has flowed out is supplied to the second chamber, and the pressure of the filler in the second chamber is opposed to the pressure of the ground even when the ground pressure changes or when the pressure of the filler in the first chamber decreases. Therefore, the water sealing property of the tail seal portion under high water pressure can be reliably maintained.

In addition, since the recesses such as the grout hole and the opening groove may fill the space formed by these recesses while passing through the first chamber, the capacity of the filler injection pump does not become enormous,
Can be easily implemented.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a shield machine showing one embodiment of the present invention, FIG. 2 is a detailed view of a part A of FIG. 1, FIG. 3 is a detailed view of a part A of FIG. 1, and FIG. FIG. 5 is a conceptual diagram of the infusion pump control device in FIG. 1, FIG. 5 is a conceptual diagram showing another example of the infusion pump control device, and FIG. 6 shows the control process of the filler pressure in the first and second chambers. The graphs, FIGS. 7 and 8 are state diagrams of the tail seal portion according to the prior art during excavation. 1 ... Shield body, 1a ... Tail skin plate, 8
1,82,83 …… tail seal, 9 …… segment, 9a ……
Grout hall, 9c ... Open groove, 101 ... First room, 102
…… Second chamber, 121,122 …… Piping for filling material injection, 131,132…
… Filling material injection pump, 171,172,173 …… Pressure sensor, 21
...... Infusion pump control device.

Continued on the front page. (72) Inventor Takayuki Shibano 1-1-1 Kodera-cho, Suma-ku, Kobe-shi, Hyogo Prefecture Inside the Japan Grease Co., Ltd. (72) Inventor Tomoyuki Arai 2-2-1-19 Gyodo, Daito-shi, Osaka No. Showa Kogyo Co., Ltd. (72) Inventor Hiroaki Miyoshi 2-2-1, Goto, Daito-shi, Osaka Showa Kogyo Co., Ltd. (56) References JP-A-2-147779 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) E21D 11/00

Claims (1)

(57) [Claims] 1. A tail skin plate of a shield body is provided with at least three levels of tail seals, and a chamber (referred to as a first chamber) divided by first and second level tail seals and segments from the face side is provided. Chamber divided by the second and third tail seals and segments (called the second chamber)
Are provided with first and second filler supply means for filling a flowable filler, respectively, and the first filler supply means causes a grout hole opened on the outer peripheral side of the segment as the shield body is propelled. The filler is supplied to the first chamber so that the recesses are substantially filled with the filler while the recesses such as the opening grooves pass through the first chamber, and the ground measured by the second filler supply means. Based on the mountain pressure, while maintaining the pressure of the filler in the second chamber at a pressure that can withstand the earth pressure and the water pressure of the surrounding ground, the filler adhering to the segments and flowing out to the ground is stored in the second chamber. A method for stopping water at a tail seal portion of a shield machine, wherein the water is supplied.