JP4896251B2 - Mud drain device in the muddy water type shield method - Google Patents

Description

  The present invention relates to a mud draining apparatus in a muddy water type shield construction method.

  In the muddy water type shield method, the muddy water mixed with the muddy water and the excavated sediment in the chamber is discharged through the mud pipe while supplying the muddy water into the chamber of the shield machine through the mud pipe. It is a method of excavating tunnels.

There are the following patent applications as inventions related to the muddy water type shield method.
The mud drain device described in Patent Application 1 includes at least a mud pump provided on a subsequent carriage of a shield machine, and a relay pump appropriately added according to a digging distance on the downstream side of the mud pump. It is configured.

Japanese Patent Application Laid-Open No. 10-1876

(1) In recent years, the excavation distance of the shield machine in the muddy water type shield method has been increased over 1000 m, and the length of the subsequent carriage has also been increased to about 200 m. Therefore, the mud pump mounted on the succeeding carriage is required to have sufficient performance to transport the muddy water to the nearest relay pump installed behind the succeeding carriage.
(2) In addition, the outer diameter of the shield when using the muddy water type shield construction method is changed from large cross-sections such as subways and underground passages to medium and small cross-sections such as water pipes and gas pipes. There is a fact that it is moving. Therefore, it is required to use a pump having a size as small as possible so that the mud pump and the relay pump do not interfere with the segment conveying device and other work facilities.
(3) According to the above (1) and (2), when the excavation distance at the construction site is long and the condition is a small cross section, the height of the sludge pump installed on the succeeding carriage is increased, and the waste mud Both pump downsizing will be required.
However, in order to raise the head of the sludge pump, it is inevitably necessary to replace it with a pump having a large size, so it is practically impossible to satisfy both of the above requirements. A proposal for a solution was sought.

  As described above, the present invention ensures the desired lift on the succeeding carriage and does not affect the arrangement or operation of other work equipment even at a site with a long excavation distance and a small cross section. One of the purposes is to provide a mud discharge device in the muddy water type shield method.

The present invention, which was made to solve the above problems, is a mud discharge device in a muddy water type shield construction method, provided appropriately on the downstream side of the tip pump unit with the tip pump unit provided on the subsequent carriage of the shield machine, comprising at least one group or more relay pump, the said front end pump units, Ri Na directly connected a plurality of variable speed pumps, the total lift of the front end pump units, the necessary lift upon excavation operation and bypass operation It is characterized by being larger than the difference .

The present invention has at least one of the following effects.
(1) Since it is possible to achieve a high head as a whole unit without increasing the size of the single unit of the sludge discharge side pump provided on the trailing carriage, it does not affect the segment transfer device and other work facilities. In addition, it is possible to cope with an increase in the length of the subsequent carriage and an increase in the excavation distance.
(2) In the conventional method in which the waste mud pump provided on the succeeding carriage is replaced by a single high-lift pump, it is necessary to provide a large-scale electric facility having a performance sufficient for starting the high-lift pump. On the other hand, the present invention allows a configuration in which the performance of each pump is substantially constant without projecting the performance of a specific pump. According to this configuration, the difference in the starting current required for starting each pump is possible. Therefore, there is no need to increase the size of the electric equipment, and it is possible to secure a work area and prevent an increase in the construction cost.
(3) Since the tip pump unit placed on the trailing carriage can be handled by using multiple pumps of the same size as the relay pump, it is possible to share parts and facilitate maintenance, and improve efficiency in terms of construction period and cost. Can be achieved.
(4) The maximum number of relay pumps can be used in accordance with the increase in the head height of the tip pump unit, so the number of relay pumps installed can be reduced, improving efficiency in terms of construction period and cost. Can be planned.
(5) Since the transport capacity of each relay pump is improved, it is easy to pre-design the installation position of each relay pump, and it is possible to respond to changes in the installation position during construction. The degree of freedom of installation is high.
(6) Since the head pump unit can secure a lift that allows a difference in pipe resistance loss that occurs during excavation operation and bypass operation, the uncontrollable zone that occurs during bypass operation can be eliminated.

The functional block diagram which shows the outline of the feed mud system using the mud apparatus of this invention. The schematic sectional drawing which shows the installation image of the front-end | tip pump unit in a tunnel cross section. (A) is a figure which shows the additional aspect of a pump at the time of using the sludge apparatus of this invention, and the required head at the time of excavation or bypass operation, (b) is the case where the conventional sludge apparatus is used It is a figure which shows the additional aspect of this pump, and the required head at the time of excavation or bypass operation.

  Hereinafter, embodiments of the mud discharge apparatus according to the present invention will be described with reference to the drawings.

<1> Overall Configuration FIG. 1 is a functional block diagram showing an outline of a sending and discharging mud system using the discharging device of the present invention.
The feed / drainage mud system provided at the rear of the shield machine includes a mud feed device 1 for transporting mud from the mud control tank A to the face chamber B, and mud that is further mixed with the soil excavated in the mud sent to the face chamber B A dewatering device 2 that transports the muddy water treatment equipment C to the ground, a detour device 3 that bypasses the mud sending device 1 and the mud discharging device 2, and a control device (not shown) that monitors and controls the devices. At least.

<2> Mud-feeding device The mud-feeding device 1 is a device for applying pressure to the face with the muddy water sent from the muddy water adjusting tank A.
The mud feeding device 1 includes a mud feeding pipe 11 disposed from a mud adjustment tank provided on the ground to a shield machine in contact with the face chamber, and at least one mud feeding pump 12 provided appropriately in the middle of the mud feeding pipe 11. , At least.
The mud pump 12 can be arranged by appropriately selecting a variable speed pump or a constant speed pump. In this embodiment, using a variable speed pump Okudoro pump P _1-1 closest upstream to the muddy water regulation tank uses a constant-speed pump other Okudoro pump P _1-2, and the like.
In addition, a variable speed mud feed pressurizing pump or the like (not shown) may be appropriately provided on the front end side of the face to compensate for the shortage of the mud feed water pressure necessary for maintaining the face pressure.

<3> Mud draining device The mud draining device 2 is a device for transporting mud mixed with earth and sand excavated by a shield machine to the ground mud treatment facility C.
The mud draining device 2 includes a mud pipe 21 for transporting mud mixed with excavated earth and sand to the mud treatment facility C, a tip pump unit 22 provided in the middle of the mud pipe 21 on the subsequent carriage of the shield machine, It has at least one or more relay pumps 23 that are provided on the downstream side of the tip pump unit 22 and appropriately in the middle of the exhaust pipe 21.
Hereinafter, each structure of the mud discharging apparatus will be described in detail.

<3.1> Front end pump unit The front end pump unit 22 is a device that is provided on the subsequent carriage and transports the muddy water mixed with the excavated earth and sand to the lower side of the subsequent carriage.
Since the tip pump unit 22 is provided in the vicinity of the tip of the succeeding carriage, the sum of the head of the relay pump per unit and the head corresponding to the length of the succeeding carriage is used to transport the muddy water to the relay pump 23. It is necessary to have at least a lift that exceeds the maximum.

A specific configuration of the tip pump unit 22 will be described.
The tip pump unit 22 needs to be configured by directly connecting a plurality of variable speed pumps.
The number of directly connected variable speed pumps can be increased or decreased as appropriate. In this embodiment, two variable speed pumps (P _2-1 / P _2-2 ) are directly connected, and theoretically, the value obtained by adding the heads included in each variable speed pump is the tip pump unit 22. Is calculated as the total head of

The term “directly connected” is different from the usage mode of the conventional pump in which the pumps are arranged at appropriate intervals so as to compensate for the shortage of the force for discharging the muddy water to the outside of the mine as the excavation distance (the transport distance of the mud) increases. This represents the intention to connect both pumps in the usage mode.
That is, the term “directly connected” means that “the piping length between the upstream variable speed pump and the downstream variable speed pump is shortened within the allowable range of the pressure resistance performance of the downstream variable speed pump. This is used to indicate the mode of `` connecting both pumps '', and is limited only to the meaning of `` directly connecting the discharge port of the upstream variable speed pump and the suction port of the downstream variable speed pump ''. It is not to be interpreted.

  In addition, it is preferable that the head of the upstream variable speed pump among the plurality of variable speed pumps constituting the tip pump unit is set to be lower than the head of the adjacent downstream variable speed pump.

<3.2> Relay pump The relay pump 23 is installed as needed in the middle of the drainage pipe 21 when the transport distance gradually increases as excavation progresses and the rotation amount of the installed pump reaches the maximum. By going, it is a device for securing the head additionally. Accordingly, the number of installed relay pumps 23 and the installation position of the relay pump 23 are appropriately designed in relation to the lift of the relay pump 23 and the excavation distance.
The relay pump 23 can be arranged by appropriately selecting a variable speed pump or a constant speed pump. In the present embodiment (FIG. 1), a variable speed pump is used for the relay pump (P _x ) closest to the downstream side from the bypass pipe of the bypass device described later or the relay pump (P _E ) closest to the muddy water treatment facility C. The other relay pumps (P ₃ , P ₄ ,... P _n ) are constant speed pumps.

  It should be noted that it is desirable to perform the setting operation so that the heads included in each relay pump 23 are smaller than the total head of the tip pump unit 22. This is because when the relay pump 23 is added, the rotational speed of the variable speed pump constituting the tip pump unit 22 is increased to within the control range so that the flow control by the tip pump unit 22 can be performed.

  In addition, it is desirable to perform the setting operation so that the head of each relay pump 23 is equal to or lower than the head of the upstream relay pump. This is to prevent cavitation between adjacent pumps.

<4> Detour Device The detour device 3 is a device for switching the mud water transport route in a stable state when the excavation operation is stopped by bypassing between the mud pipe 11 and the mud pipe 21.
The bypass device 3 can be a bypass pipe connected between the mud pipe and the mud pipe, or a device provided with a known bypass mechanism such as a valve set (not shown), and thus detailed description thereof is omitted. .

<5> Control Device The control device is a flow meter, a density meter, a pressure gauge, or the like in which the operating state in any or all of the means constituting the shield machine and the sending and discharging mud system is appropriately provided in each device. This is a device for monitoring one by one with known detection means (not shown) and controlling the operation of each device based on the detection data. Since a known control system can be used for the control device, detailed description thereof is omitted.

<6> Actions / Effects Next, main actions and effects of the mud discharge device of the present invention will be described below.

<6.1> Reducing the number of relay pumps installed When relay pumps 23 are added as excavation progresses, the rotational speed of tip pump unit 22 on the following carriage is increased to within the control range, and flow control by the tip pump unit is performed. In order to be able to do so, the head [H2] of the tip pump unit and the head [Hn] of the relay pump are generally designed to maintain a relationship of about H2−Hn> 5 (m).
Then, following the increase in the head height of the tip pump unit 22, the rear relay pump 23 can also be used at an increased rotational speed so as to raise the head to a limit value that maintains the above relationship. If it does so, since the transportation capability which each relay pump has naturally improves, the number of installation of a relay pump can be reduced finally, and it can contribute to shortening of a construction period and reduction of construction cost.

<6.2> Improving the flexibility of installation positions of relay pumps As described above, the additional interval between relay pumps becomes longer due to the improved performance of each relay pump. In addition, it is easy to respond to requests to change the installation position during construction.
That is, since the degree of freedom of installation of each pump is high before and after construction, it is excellent in workability, and in turn contributes to the improvement of construction period and construction cost.

<6.3> Securing work area in tunnel FIG. 2 is a schematic cross-sectional view showing an installation image of a tip pump unit in a tunnel cross section.
Because it is necessary to use a high-lift pump c that exhibits the size shown in Fig. 2 (height: approx. 2500mm / width: approx. 1400mm) in order to obtain a suitable lift at the site having a trailing carriage length of around 200m. In the field where the shield outer diameter D ₁ is about 3000 mm, the ratio to the effective cross-sectional area (the cross-sectional area of the space above the track b) increases, and there is a problem of interfering with other work areas. .
However, according to the present invention, a pump exhibiting a size (height: about 1400 mm / width: about 1000 mm) that does not interfere with other work areas can be selected, and a plurality of such pumps are directly connected to a tip pump. By configuring the unit d, the above problem can be solved while ensuring a high head.

<6.4> Miniaturization of electrical equipment In addition, the conventional method of replacing the mud-side pump provided on the succeeding carriage with a single high-lift pump has a performance that only corresponds to the startup of the high-lift pump. Whereas it is necessary to provide a large-scale electric facility having the present invention, the present invention can be operated while maintaining the scale of each pump substantially constant without projecting the performance of a specific pump, and starting each pump. There is no need to increase the size of the electric equipment because there is no difference in the starting current required for the operation.

<6.5> Improved maintainability Also, when the pump unit 22 and the relay pump 23 arranged on the succeeding carriage are unified with a pump of the same scale, parts can be shared and maintenance can be facilitated. Efficiency can be improved in terms of construction costs.

λ：係数、L：配管長[m]、d：管内径[m]
v：流速[m/s]、g：重力加速度[m/s²]、δ：液比重
上記式より明らかな通り、配管の抵抗損失ｈｆは液比重δに比例して増加するため、掘削距離の長いシールド及び掘削速度の速いシールドでは、この比重差による配管抵抗損失の変化が大きく影響を及ぼすこととなる。 <6.6> Eliminating the uncontrollable zone Since there is a difference in pipe resistance loss between the excavation operation and the bypass operation of the sending and discharging mud system, a difference occurs in the required lift.
For example, the resistance loss hf of the pipe is obtained by the following equation.

λ: Coefficient, L: Pipe length [m], d: Pipe inner diameter [m]
v: Flow velocity [m / s], g: Gravitational acceleration [m / s ² ], δ: Liquid specific gravity As is clear from the above equation, the resistance loss hf of the pipe increases in proportion to the liquid specific gravity δ, so the excavation distance In a long shield and a shield with a high excavation speed, a change in pipe resistance loss due to the difference in specific gravity greatly affects.

For example, when the excavation distance is 2500 m, the equivalent straight pipe length of the mud pipe is about 2750 m as a guide. This is compared with the total head in consideration of indentation due to piping resistance and face pressure (P: face pressure [kPa]) when specific gravity δb = 1.20 during bypass operation and δa = 1.30 during excavation.
Liquid specific gravity δa = 1.30 Hfa = 0.0981 (m / m) × 2750 (m) = 269.8 (m)
Liquid specific gravity δb = 1.20 Hfa = 0.0905 (m / m) × 2750 (m) = 248.9 (m)
TH = Hf + Hc + h-((P / 9.8) / δ) -height difference
THa = 269.8 + 42.0 + 12.0- (200 / 9.8) /1.30-10.2=297.9 (m)
THb = 248.9 + 42.0 + 12.0- (200 / 9.8) /1.20-10.2=275.7 (m)
∴ THa−THb = 297.9−275.7 = 22.2 (m)
It becomes.

Fig. 3 (a) is a diagram showing an additional aspect of the pump when using the mud discharge device of the present invention and the required head during excavation or bypass operation, and Fig. 3 (b) is a conventional mud drain device. It is a figure which shows the additional aspect of the pump at the time of using, and the required head at the time of excavation or bypass operation.
When the number of revolutions of the tip pump unit 22 (P ₂ * 2) is maximized and the relay pump 23 is added, or when the relay pump 23 (P _n ) is added, the excavation operation is switched to the bypass operation. At this time, when the change in the total head during each operation is examined, if the sum of the head differences between the excavation operation and the bypass operation exceeds the maximum head of the tip pump unit 22, the rotational speed of the tip pump unit 22 is zero. Since the drainage flow rate exceeds the set value, the required head of the tip pump unit 22 becomes negative, and a phenomenon that the flow rate control becomes impossible occurs (referred to as “occurrence of uncontrollable zone”).

  However, the sludge discharge device of the present invention has a tip more than the difference of the required head by raising the tip pump unit 22 even when the required head changes when switching from excavation operation to bypass operation. Since the range of the head of the pump unit 22 can be widened, the occurrence of the uncontrollable zone can be suppressed beforehand by appropriately controlling the operation of the tip pump unit 22.

DESCRIPTION OF SYMBOLS 1 Mud feed device 2 Mud discharge device 21 Waste mud pipe 22 Tip pump unit 23 Relay pump 3 Detour device a Shield section b Track c High lift pump d Tip pump unit

Claims (1)

A mud drain device in the muddy water type shield method,
A tip pump unit provided on the trailing carriage of the shield machine;
Provided at the downstream side of the tip pump unit as appropriate, and at least one relay pump, and
It said tip pump unit, Ri Na directly connected a plurality of variable speed pumps,
The total head of the tip pump unit is larger than the difference between the required heads during excavation operation and bypass operation ,
A mud drainer in the muddy water shield method.

Images