JP2017223005A - Muddy water processing method and muddy water processing facility of muddy water type shield driving - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a muddy water processing method and a muddy water processing facility of a muddy water type shield driving capable of adding an appropriate amount of a coagulant to suit a change with time of a property of the muddy water.SOLUTION: A muddy water processing facility 10 of a muddy water type shield driving performs coagulant processing by adding a coagulant at a midway point of a muddy water pipe 45 while muddy water flows, and includes a coagulant pump control part 65a that controls a transfer flow amount of the coagulant to the muddy water pipe 45 transferred by coagulant transfer means 55. The coagulant pump control part 65a calculates a necessary transfer flow amount of the coagulant to the muddy water pipe 45 based on a measurement signal from a specific gravity meter 43 and a measurement signal from a flow meter 47, and controls a discharging operation of a coagulant pump 57 so that the transfer flow amount would be the calculated necessary transfer flow amount.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a muddy water treatment method and a muddy water treatment facility in a muddy water type shield method in which muddy water is circulated and the excavation wall surface (face) is held down by muddy water pressure, and more particularly, the amount of flocculant added to the muddy water is controlled. The present invention relates to a muddy water treatment method and a muddy water treatment facility.

  The muddy water type shield method is a method of forming a shield tunnel while digging the ground with a muddy type shield machine, and pressurized muddy water into the pressure chamber formed immediately after the cutter face plate of the shield machine, It circulates and fills through a mud pipe and a mud pipe and digs machinery while stabilizing the face. In this mud type shield construction method, the generated excavated soil is fluidly transported as mud water together with the mud water, the excavated soil is separated from the discharged mud water in the mud treatment facility, and the mud water from which the excavated soil has been separated is recycled and reused. According to this muddy water type shield construction method, the application range with respect to the soil quality of the ground is wide, continuous construction is possible, and the facilities in the mine and shafts can be miniaturized (see Patent Document 1).

  As a method for aggregating muddy water in the muddy water type shield construction method, a method using an inorganic flocculant such as polyaluminum chloride (hereinafter referred to as “PAC”) is widely known. In addition, an organic flocculant such as polydimethyldiallylammonium chloride (DMDAC) is also used in combination with PAC (see Patent Document 2).

JP-A-11-256984 JP-A-6-182353

  For example, when PAC is added during muddy water treatment, if the amount of filtered water reaches a peak at a certain amount added, the amount of filtered water does not increase even if the amount added is increased further, but the amount of filtered water decreases. Therefore, in order to avoid the deterioration of the properties of reused mud due to excessive addition of the flocculant and the increase in chemical cost, it is necessary to make the addition amount appropriate.

The required addition amount Xp of PAC is proportional to the amount of suspended particles (soil particle amount) in the muddy water, and the required addition amount of PAC per ton of suspended particles (SS) contained in the muddy water is 25 kg.
Here, for example, the transfer amount Q of muddy water is 5.0 m ³ / min, the specific gravity γt of the muddy water is 1.35, the true specific gravity Gs of the soil particles is 2.65, the PAC specific gravity Gp is 1.20, and the muddy water flows. When PAC is added in the middle of the muddy water flow path, the required transfer flow rate q [m ³ / min] of PAC to the muddy water flow path is determined as follows.

First, the soil particle weight Ws in 1 m ^{3 of} muddy water is obtained using the following formula.
Ws = Gs · [(γt−1) / (Gs−1)] · V
Since Gs is 2.65, γt is 1.35, and V is 1, Ws is obtained as follows.
Ws = 2.65 × [(1.35-1) / (2.65-1)] × 1
= 0.562 t / m ³
Next, the muddy water transfer weight Wo is obtained using the following formula.
Wo = Q · Ws
Since Q is 5.0 and Ws is 0.562, Wo is obtained as follows.
Wo = 5.0 × 0.562 = 2.810 t / min
If the transfer weight of PAC is Wp, the following two equations are established.
Wp = q · Gp
Xp = Wp / Wo
From these two equations, the required transfer flow rate q of PAC can be expressed by the following equation.
q = Xp · Wo / Gp
Since Xp is 25, Wo is 2.810, and Gp is 1200, q is obtained as follows.
q = 25 × 2.810 / 1200
= 0.059 m ³ / min (60 L / min)

  By the way, in the muddy water type shield construction method, there are areas where the clay excavation machine is mainly composed of viscous soil, there are areas mainly composed of gravel, and there are areas where several kinds of soil are mixed. The properties of the ground may change. In this case, the properties of the muddy water will fluctuate, and the specific gravity of the muddy water will fluctuate greatly over time.

In the conventional muddy water treatment method, the necessary transfer flow rate q of PAC is fixed at 0.059 m ³ / min (60 L / min) obtained as described above, so the muddy water properties are constant and the specific gravity of muddy water is 1 If the change is about 35, the PAC addition amount is appropriate, but if the specific gravity of the muddy water changes greatly as the properties of the muddy water changes over time, the PAC addition amount becomes excessive or conversely too low. When the PAC addition amount is excessive, the properties of the reused mud are deteriorated and the chemical cost is increased. When the PAC addition amount is too small, there is a problem that the aggregation failure is caused.

  The present invention has been made in view of the above-described problems, and even if a temporal variation occurs in the properties of the muddy water, an appropriate amount of a flocculant can be added corresponding to the variation. An object of the present invention is to provide a muddy water treatment method and a muddy water treatment facility in the construction method.

In order to achieve the above object, the muddy water treatment method in the muddy water type shield method according to the first invention is:
A muddy water treatment method in a muddy water type shield method, in which a flocculant is added in the middle of the muddy water flow path through which the muddy water flows in the muddy water type shield method,
While measuring the specific gravity of the mud before the flocculant is added, measure the flow rate of the mud before the flocculant is added, and based on the measured specific gravity and flow rate of the mud water, The required transfer flow rate of the flocculant is calculated, and the transfer flow rate of the flocculant with respect to the muddy water channel is controlled so as to be the calculated required transfer flow rate.

  In the first invention, diluting water is added to the flocculant in the middle of the flocculant flow path through which the flocculant flows to dilute the flocculant, and the transfer flow rate of the diluting water to the flocculant flow path is set. It is preferable to control the concentration of the flocculant by controlling (second invention).

Next, the muddy water treatment facility in the muddy water type shield construction method according to the third invention is:
It is a muddy water treatment facility in a muddy water type shield method in which a flocculant is added to the muddy water flow path through which the muddy water flows in the muddy water type shield method,
A specific gravity meter that measures the specific gravity of the mud before the flocculant is added, a flow meter that measures the flow rate of the mud before the flocculant is added, and the flocculant is transferred to the mud flow path. A flocculant transfer means; and a flocculant transfer flow rate control means for controlling the flow rate of the flocculant transferred to the mud flow path by the flocculant transfer means,
The flocculant transfer flow rate control means calculates the required transfer flow rate of the flocculant for the muddy water flow path based on the measurement signal from the hydrometer and the measurement signal from the flow meter, and calculates the required transfer flow rate The flow rate of the flocculant to the mud flow path is controlled so that

  In the third invention, diluting water is added to the flocculant in the middle of the flocculant channel through which the flocculant flows to dilute the flocculant, and the diluted water is transferred to the flocculant channel. A dilution water transfer means is provided, and a dilution water transfer flow control means for controlling a transfer flow rate of the dilution water to the flocculant channel by the dilution water transfer means is provided, and the dilution water transfer flow control means It is preferable to control the concentration of the flocculant by controlling the flow rate of the dilution water to the agent flow path (fourth invention).

  According to 1st invention and 3rd invention, while measuring the specific gravity of the muddy water before a flocculant is added, the flow rate of the muddy water before a flocculant is added is measured, Based on the above, the required transfer flow rate of the flocculant to the mud flow channel is calculated, and the transfer flow rate of the flocculant to the mud flow channel is controlled to be the calculated required transfer flow rate. Even if a temporal variation occurs, an appropriate amount of the flocculant can be added in accordance with the variation. Thereby, since excessive addition of a flocculant can be suppressed, chemical | medical agent cost can be reduced. Moreover, since chemical | medical agent mixing contained in the filtrate generated at the time of spin-drying | dehydration can be suppressed as much as possible, a high quality mud water can be produced. In addition, the moisture content of the dehydrated cake can be reduced and the press cycle time can be shortened quantitatively by optimizing the addition amount of the flocculant.

  By the way, even if the addition amount of the flocculant is the same, the flocculant effect is different if the concentration of the flocculant is different. Therefore, by adopting the configuration of the second invention or the fourth invention, that is, the flocculant is diluted by adding dilution water in the middle of the flocculant flow path through which the flocculant flows. By controlling the flow rate of diluting water with respect to the agent flow path, by controlling the concentration of the flocculant, it is possible to add a high concentration flocculant or a low concentration flocculant depending on the properties of the mud, A higher aggregation effect can be obtained.

1 is a schematic system configuration diagram of a muddy water treatment facility in a muddy water type shield construction method according to an embodiment of the present invention. It is a flowchart which shows the processing content of the coagulant | flocculant pump control part. It is a flowchart which shows the processing content of a dilution water pump control part.

  Next, specific embodiments of the muddy water treatment method and muddy water treatment facility in the muddy water type shield method according to the present invention will be described with reference to the drawings.

<Description of the muddy water type shield construction method>
The muddy water type shield method is a method in which a shield tunnel is formed by the muddy water type shield machine 1, and the pressure chamber 4 formed by the partition wall 3 immediately after the cutter face plate 2 of the shield machine 1 is pressurized. The muddy water is circulated and filled through the mud pipe 5 and the mud pipe 6, and the machine is dug while the face is stabilized. In this muddy water type shield construction method, the generated excavated earth and sand is fluidly transported together with the muddy water, the excavated earth and sand is separated at the muddy water treatment facility 10, and the muddy water from which the excavated earth and sand is separated is re-circulated and reused. The segments are sequentially assembled by a segment assembling apparatus (not shown) behind 1 to construct a shield tunnel.

<Outline explanation of muddy water treatment equipment>
The muddy water treatment facility 10 in this muddy water type shield construction method mainly includes a primary treatment plant 11, a secondary treatment plant 12, and a tertiary treatment plant 13.
The primary treatment plant 11 separates and removes sand from the mud water accompanying the excavated earth and sand discharged from the pressure chamber 4 through the mud pipe 5. The secondary treatment plant 12 separates and removes the clay and silt from the surplus muddy water after the primary treatment excluding the muddy water that is recycled and reused. The tertiary treatment plant 13 adjusts surplus water separated by the secondary treatment. Below, each processing plant 11,12,13 is demonstrated more concretely.

<Description of primary processing plant>
The primary treatment plant 11 is a facility that first treats excavated earth and sand contained in the wastewater sent from the face. The primary treatment plant 11 includes a sand collector 21 of, for example, a vibration dewatering sieve system, and the sand collector 21 separates sandy components, that is, gravel, sand, clay, and silt lump from wastewater. The waste mud water from which the sand is separated and removed is temporarily stored in the muddy water receiving tank 22 of the sand collector 21 and is pumped to the secondary treatment plant via the cyclone 23 and the pipe 24 attached to the sand collector 21.
In addition, the sandy part isolate | separated by the sand collector 21 is sent to the primary earth-and-sand pit 25 by the conveying apparatus etc. which are not shown in figure as primary processing soil.

<Description of secondary treatment plant>
The secondary treatment plant 12 is mainly composed of a conditioning tank 31, an excess mud water tank 32, a slurry tank 33 for generating flocs, a PAC tank 34 for storing an inorganic flocculant such as PAC, or a DMDAC. A DMDAC tank 35 that stores an organic flocculant and a dehydrator 36 are used.

  In the adjustment tank 31, waste mud sent from the primary treatment plant 11, a good liquid of mud from the mud tank 37, a CMC agent (thickener) from the CMC tank 38, and fresh water from the fresh water tank 39, which will be described later. The filtrate from the tertiary treatment plant 13 (drainage tank 51) is mixed and adjusted so as to have a quality that can be recycled and reused as muddy water for shield construction. The adjusted muddy water is returned to the pressure chamber 4 of the shield machine 1 through the mud pipe 6. On the other hand, surplus muddy water in which excavated soil has melted is sent to a surplus muddy water tank 32 through a muddy water distribution pipe 40. The surplus muddy water tank 32 is provided with a muddy water circulation pipe 42 for returning muddy water led out of the tank by the operation of the pump 41 into the tank. The mud circulation pipe 42 is provided with a hydrometer 43 so that the specific gravity of the mud stored in the surplus mud tank 32 is measured by the hydrometer 43.

  A slurry tank 33 is disposed on the downstream side of the excess muddy water tank 32. A muddy water circulation pipe 45 connecting the surplus muddy water tank 32 and the slurry tank 33 is provided with a muddy water pump 46, a flow meter 47 and a line mixer 48 in order from the surplus muddy water tank 32 toward the slurry tank 33. Between the flow meter 47 and the line mixer 48 in the muddy water distribution pipe 45, a coagulant addition unit 45a for adding a coagulant to the muddy water flowing in the muddy water distribution pipe 45 by the coagulant transfer means 55 described later. Is provided. Then, the muddy water stored in the surplus muddy water tank 32 is pumped to the slurry tank 33 through the muddy water circulation pipe 45 by the operation of the muddy water pump 46, and the muddy water before the flocculant is added in the coagulant adding part 45a. The flow rate is measured by the flow meter 47, and the muddy water flowing in the muddy water circulation pipe 45 and the flocculant added by the flocculant addition unit 45 a are mixed by the line mixer 48, and this mixed liquid is introduced into the slurry tank 33. The

  In the slurry tank 33, the mud and the flocculant are agitated to promote flocking, and the silty and clay components are precipitated and concentrated. Precipitated and concentrated silt and clay components are sent to a dehydrator 36 for dehydration.

  As the dewatering device 36, for example, a filter press is used, and the dewatered cake generated by the dewatering process by the dewatering device 36 is sent to the secondary sediment pit 50 as a secondary treated soil by a transport device 49 such as a belt conveyor. It is done. On the other hand, the separated water generated during the dehydration process in the dehydrator 36 is sent to the tertiary treatment plant 13 (the filtrate tank 51).

<Description of tertiary treatment plant>
The tertiary treatment plant 13 includes a filtrate tank 51 into which the separated water from the dehydrator 36 is introduced. In this drainage tank 51, the quality is adjusted to a quality that can be used as construction water for shield construction by adjusting the pH, etc., and the adjusted filtrate is sent to the adjustment tank 31 via the pipe 52 to circulate mud. Is used as a mixed water for adjusting the quality of the water, and is sent to a coagulant supply pipe 56 described later to be used as a diluting water for diluting the coagulant.

  Next, the flocculant transfer means 55 for transferring the flocculant stored in the PAC tank 34 or the DMDAC tank 35 to the mud flow pipe 45 when adding the flocculant to the mud flowing in the mud flow pipe 45 will be described. To do.

<Description of flocculant transfer means>
The flocculant transfer means 55 includes a flocculant supply pipe 56, and a flocculant pump 57 is disposed in the middle of the flocculant supply pipe 56. Here, the flocculant supply pipe 56 is a pipe for connecting the PAC tank 34 or the DMDAC tank 35 and the flocculant addition part 45 a in the mud circulation pipe 45. The flocculant pump 57 is provided with the suction side directed to the PAC tank 34 or the DMDAC tank 35, and the discharge side directed to the muddy water circulation pipe 45, and operates in response to the flocculant pump control signal. Is to be controlled. A flow meter 58 is disposed on the discharge side of the flocculant pump 57 in the flocculant supply pipe 56.

  In the flocculant transfer means 55, the flocculant (PAC, DMDAC) stored in the PAC tank 34 or DMDAC tank 35 is transferred to the muddy water distribution pipe 45 through the flocculant supply pipe 56 by the operation of the flocculant pump 57. The flow rate of the flocculant to be pumped is measured by the flow meter 58.

  In addition, between the flocculant pump 57 and the flowmeter 58 in the flocculant supply pipe 56, for adding dilution water to the flocculant flowing in the flocculant supply pipe 56 by the diluting water transfer means 60 described later. A dilution water addition unit 56a is provided.

  Next, when adding dilution water to the flocculant flowing in the flocculant supply pipe 56, dilution water transfer means 60 for transferring the filtrate stored in the filtrate tank 51 to the flocculant supply pipe 56 as dilution water. Will be described.

<Description of dilution water transfer means>
The diluting water transfer means 60 includes a diluting water supply pipe 61, and a diluting water pump 62 is disposed in the middle of the diluting water supply pipe 61. Here, the dilution water supply pipe 61 is a pipe for connecting the dilution water addition part 56 a in the flocculant supply pipe 56 and the filtrate tank 51. The dilution water pump 62 is provided with the suction side directed toward the drainage tank 51 and the discharge side directed toward the flocculant supply pipe 56. A flow meter 63 is disposed on the discharge side of the dilution water pump 62 in the dilution water supply pipe 61.

  In the dilution water transfer means 60, the filtrate stored in the filtrate tank 51 is pumped as dilution water to the coagulant supply pipe 56 via the dilution water supply pipe 61 by the operation of the dilution water pump 62, and pumped. The flow rate of the diluted water to be measured is measured by the flow meter 63.

<Description of automatic control device>
The muddy water treatment facility 10 includes an automatic control device 65 that automatically controls various devices constituting the facility. The automatic control device 65 is mainly configured by a CPU (Central Processing Unit), a memory for storing various data, a predetermined program, and the like, and other hardware such as an electric circuit (all not shown). A specific gravity meter 43, a flocculant pump 57, a dilution water pump 62, and flow meters 47, 58, and 63 are connected to the automatic control device 65 so that predetermined signals can be transmitted.

<Description of CPU functional module>
In a CPU (not shown) in the automatic control device 65, a predetermined program is appropriately read from a memory (not shown) and executed, thereby executing a flocculant pump controller 65a (corresponding to the “flocculant transfer flow rate control means” of the present invention). In addition, various functional modules such as the dilution water pump control unit 65b (corresponding to the “dilution water transfer flow rate control means” of the present invention) are virtually constructed, and the coagulant pump 57 is constructed by each constructed functional module. The operation control of the dilution water pump 62 is performed.

  Next, the PAC required transfer flow rate, the DMDAC required transfer flow rate, and the dilution required for performing the operation control of the coagulant pump 57 by the coagulant pump control unit 65a and the operation control of the dilution water pump 62 by the dilution water pump control unit 65b. Each calculation method of the required water transfer flow rate will be described below.

First, the main symbols used in the following calculations are defined as follows.
Q: Mud flow rate [m ³ / min]
γt: Mud specific gravity Gs: Soil particle true specific gravity (2.65 in this example)
Xp: PAC required addition amount (25 kg / sst in this example)
Xd: DMDAC required addition amount (2.1 kg / sst in this example)
Gp: PAC specific gravity (1.20 in this example)
Gd: DMDAC specific gravity (1.10 in this example)
q _P : PAC required transfer flow rate [m ³ / min]
q _D : DMDAC required transfer flow rate [m ³ / min]
q _W : Necessary transfer flow rate of dilution water [m ³ / min]
N: dilution factor

<Calculation of PAC required transfer flow rate>
First, the soil particle weight Ws [t / m ³ ] in 1 m ^{3 of} muddy water is obtained using the following formula.
Ws = Gs · [(γt−1) / (Gs−1)] · V
Here, since Gs is a fixed value, which is 2.65 in this example, and V is 1, Ws is obtained as follows.
Ws = 2.65 × [(γt−1) / (2.65-1)] × 1
= 1.61 × (γt−1)
Next, the muddy water transfer weight Wo [t / min] is obtained using the following equation.
Wo = Q · Ws
= 1.61 × (γt−1) · Q
When the PAC transfer weight is Wp [kg / min], the following two equations are established.
Wp = q _P · Gp
Xp = Wp / Wo
Here, Gp is 1200, and Xp is a fixed value, which is 25 kg / sst in this example. Therefore, the following equation is established from these two equations.
25 = 1200 · q _P /[1.61×(γt−1)·Q]
From the above formula, the PAC required transfer flow rate q _P [m ³ / min] is represented by the following formula (1).
q _P = 25 × [1.61 × (γt−1) · Q] / 1200 (1)
Thus, it is possible to determine the mud density γt based on the signal from the specific gravity meter 43, a mud flow rate Q based on the signal from the flow meter 47, the PAC must transfer flow rate q _P by the above formula (1).

<Calculation of required flow rate for DMDAC>
The xp Xd, the Gp replaced by Gd, in the same manner as the calculation of the PAC must transfer flow rates _{q P,} it is possible to obtain the DMDAC required transfer rate _{q D} ^[m 3 / min] by the following equation (2).
q _D = 2.1 × [1.61 × (γt−1) · Q] / 1100 (2)

<Calculation of diluting water required transfer flow rate>
The dilution water required transfer flow rate q _W [m ³ / min] is obtained by the following formula using a dilution ratio N appropriately set according to the properties of the muddy water.
q _W = q _D · (N−1)
By this equation and the equation (2), dilution water must transfer flow rates q _W is expressed by the following (3).
q _W = {2.1 × [1.61 × (γt−1) · Q] / 1100} · (N−1)
... (3)

  Next, processing contents of the flocculant pump control unit 65a will be described with reference to the flowchart of FIG. Note that the symbol “S” in FIG. 2 indicates a step, and the processes in steps S1 to S4 are repeatedly executed at predetermined cycle times.

<Explanation of flocculant required transfer flow control>
First, the flocculant pump control unit 65a reads the measurement signal of the hydrometer 43 and also reads the measurement signal of the flow meter 47 (S1). Then, the above equation based on the read measurement signal (1) and (2), calculates the PAC must transfer flow rate _{q P} and DMDAC must transfer flow rate _{q D} (S2). Next, a predetermined flocculant pump control signal is output to the flocculant pump 57, and the actual transfer flow rate of the flocculant pump 57 based on the measurement signal (feedback signal) of the flow meter 58 is the required transfer flow rate (q _P + q _D ) To control the discharge operation of the flocculant pump 57 (S3 to S4).

In this way, the specific gravity of the mud before the addition of PAC and DMDAC is measured by the hydrometer 43, and the flow rate of the mud before the addition of PAC and DMDAC is measured by the flow meter 47. preparative PAC must transfer flow rate _{q P} and DMDAC must transfer flow rates _{q D} for mud flow pipe 45 is calculated based on, the calculated required transport rate _q P, coagulant pump 57 for mud flow pipe 45 such that _{q D} Since the flow rate of the PAC and DMDAC is controlled, a suitable amount of flocculant can be added in response to the fluctuation even if the mud water changes with time. Thereby, since excessive addition of a flocculant can be suppressed, chemical | medical agent cost can be reduced. Moreover, since chemical | medical agent mixing contained in the filtrate generated at the time of spin-drying | dehydration can be suppressed as much as possible, a high quality mud water can be produced. In addition, the moisture content of the dehydrated cake can be reduced and the press cycle time can be shortened quantitatively by optimizing the addition amount of the flocculant.

  Next, the processing content of the dilution water pump control part 65b is demonstrated using the flowchart of FIG. Note that the symbol “T” in FIG. 3 indicates a step, and the processing from step T1 to step T5 is repeatedly executed every predetermined cycle time.

<Explanation of required flow control for dilution water>
First, the dilution water pump control unit 65b reads the measurement signal of the hydrometer 43 and also reads the measurement signal of the flow meter 47 (T1). Next, the dilution factor N that is automatically set based on the read measurement signal of the hydrometer 43 and the measurement signal of the flow meter 47 is read (T2). Then, the above equation (3) based on the read measurement signal and dilution N, calculates the dilution water necessary transfer rate q _W (T3). Then, by outputting a predetermined dilution water pump control signal to the dilution water pump 62, so that the actual transfer flow rates of the dilution water pump 62 based on the flow meter 63 of the measuring signal (feedback signal) is required transfer rate q _W The discharge operation of the dilution water pump 62 is controlled (T4 to T5).

  Thus, diluting water is added to the flocculant (PAC or DMDAC) in the middle of the flocculant supply pipe 56 through which the flocculant flows to dilute the flocculant. By controlling the concentration of the flocculant, it is possible to add a high concentration flocculant or a low concentration flocculant according to the properties of the muddy water, so that a higher aggregation effect can be obtained.

  As described above, the muddy water treatment method and the muddy water treatment facility in the muddy water type shield construction method of the present invention have been described based on one embodiment, but the present invention is not limited to the configuration described in the above embodiment, and the gist thereof is as follows. The configuration can be changed as appropriate without departing from the scope.

  The muddy water treatment method and the muddy water treatment facility in the muddy water type shield method of the present invention have a characteristic that even if a change in time of the muddy water occurs, an appropriate amount of a flocculant can be added corresponding to the change. Therefore, it can be suitably used for muddy water treatment when performing a muddy water type shield construction method on the ground where the properties of soil changes, and industrial applicability is great.

DESCRIPTION OF SYMBOLS 1 Shield machine 10 Muddy water treatment equipment 32 Surplus muddy water tank 33 Slurry tank 34 PAC tank 35 DMDAC tank 43 Hydrometer 45 Muddy water distribution pipe (muddy water flow path)
47 Flow meter 55 Coagulant transfer means 56 Coagulant supply pipe (coagulant flow path)
57 flocculant pump 60 diluting water transfer means 61 diluting water supply pipe 62 diluting water pump 65 automatic controller 65a flocculant pump control unit (flocculating agent transfer flow rate control means)
65b Dilution water pump controller (dilution water transfer flow rate control means)

Claims (4)

A muddy water treatment method in a muddy water type shield method, in which a flocculant is added in the middle of the muddy water flow path through which the muddy water flows in the muddy water type shield method,
While measuring the specific gravity of the mud before the flocculant is added, measure the flow rate of the mud before the flocculant is added, and based on the measured specific gravity and flow rate of the mud water, A muddy water treatment method in a muddy water type shield method, wherein a necessary transfer flow rate of the flocculant is calculated, and the transfer flow rate of the flocculant to the muddy water flow path is controlled to be the calculated required transfer flow rate.   By adding dilution water in the middle of the flocculant flow path through which the flocculant flows with respect to the flocculant, the flocculant is diluted, and by controlling the flow rate of the dilution water to the flocculant flow path, 2. The muddy water treatment method according to claim 1, wherein the concentration of the flocculant is controlled. It is a muddy water treatment facility in a muddy water type shield method in which a flocculant is added to the muddy water flow path through which the muddy water flows in the muddy water type shield method,
A specific gravity meter that measures the specific gravity of the mud before the flocculant is added, a flow meter that measures the flow rate of the mud before the flocculant is added, and the flocculant is transferred to the mud flow path. A flocculant transfer means; and a flocculant transfer flow rate control means for controlling the flow rate of the flocculant transferred to the mud flow path by the flocculant transfer means,
The flocculant transfer flow rate control means calculates the required transfer flow rate of the flocculant for the muddy water flow path based on the measurement signal from the hydrometer and the measurement signal from the flow meter, and calculates the required transfer flow rate The muddy water treatment facility in the muddy water type shield construction method is characterized in that the transfer flow rate of the flocculant to the muddy water flow path is controlled. Dilution water transfer means for adding dilution water in the middle of the flocculant flow path through which the flocculant flows with respect to the flocculant so as to dilute the flocculant and transferring the dilution water to the flocculant flow path. And providing a dilution water transfer flow rate control means for controlling the transfer flow rate of the dilution water to the flocculant flow path by the dilution water transfer means, the dilution water transfer flow rate control means for the flocculant flow path with respect to the flocculant flow path The muddy water treatment facility according to claim 3, wherein the concentration of the flocculant is controlled by controlling the flow rate of dilution water.

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