JP2001193099A - System and method for fractionating earth and sand - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system and method for fractionating earth and sand in excavation using muddy water. SOLUTION: The adhesion state of the water of a solid content that has fallen from a lower net chute 82 to a belt conveyor 112 is discriminated by a moisture meter 110. By changing the rotary direction of the belt conveyor 112, solid contents with larger and smaller adhesion ratio of water content are sent to a secondary treated soil-retaining device as muddy soil and to a primary treated soil-retaining device as earth and sand, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sediment separation system and a sediment separation method in a muddy method for transporting excavated sediment with muddy water.

[0002]

Background Art and Problems to be Solved by the Invention
In drilling by the muddy water circulation method such as the muddy pressure shield method or the reverse circulation drill method, the excavated material having a particle size of 74 μm or less is transported by mixing the excavated earth and sand into the muddy water having the specified properties. It had to be treated as "sludge". For this reason, when excavating a viscous soil layer, a large amount of excavated matter to be treated as industrial waste is discharged, so that the burden on the environment is increased, which has been a serious social problem.

[0003] In order to treat excavated earth and sand as “sludge” instead of “sludge” as much as possible, the applicant of the present application has proposed a method of excavating a ground such as hard clay ground.
It has been proposed to propose a technology capable of collecting excavated earth and sand in a lump while securing the same strength as the ground (for example, Japanese Patent Application No. 11-86045).

[0004] However, even if excavated sediment, which is a hard clayey soil, is excavated and collected (hereinafter referred to as "solid collection") while securing the same strength as a solid mass in a lump, the excavated sediment is long distance (long) in muddy water. Time) When transported, muddy water containing fine particles of 74 μm or less adheres to the surface of the viscous soil mass, and it is considered that a large amount of moisture is attached, and it is rarely treated as “sludge”. Did not.

[0005] Of course, when such a solid recovery technique is not used, fine particles having a particle diameter of 74 μm or less are loosened and collected as a muddy excavated matter containing a large amount of water.
Was treated as "sludge."

[0006] Conversely, there is a case where what should be handled as "sludge" is blindly handled as "earth and sand".

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to collect a viscous soil mass or the like which tends to be in a "muddy and fluid" state as "soil and sand" as much as possible. It is an object of the present invention to provide a possible sediment separation system and method.

[0008]

In order to solve the above-mentioned problems, a sediment separation system according to the present invention is characterized in that in a drilling method for transporting excavated sediment with muddy water, the system is separated from the muddy water containing the excavated sediment by predetermined separating means. A solid content, a sediment separation system for separating the sediment from the soil and sludge, detecting the state of water adhesion of the solid content, determining means for determining whether the soil or sludge based on the detection result, Based on
Conveying the solid content determined as sediment to sediment storage means,
And separating and conveying means for conveying the solid matter determined as sludge to the sludge storing means.

According to the present invention, it is possible to automatically and objectively discriminate between earth and sand and sludge by judging the state of adhesion of the water content of the solid content. That is, if the degree of adhesion of moisture is high, it is discriminated as sludge, and if the degree of adhesion of water is low, it is discriminated as earth and sand, and classification is possible.

Here, the solid content means a particle size of 75 μm.
It means a viscous soil mass excavated in a lump having a particle size of 75 μm or more while retaining the above coarse fraction (generally classified as sand or gravel) and the structural skeleton in the ground state.

As a method of this discrimination, specifically, a relative discrimination method of discriminating sludge if the water content is higher than the natural water content of the ground, or, for example, using a water content of 65% as a reference value, If the water content is higher than the reference value, an absolute discrimination method of discriminating sludge can be adopted.

In the latter case, the reference value may be changed between about 40% and 65% depending on the soil characteristics of the object to be excavated.

As described above, by setting the objective criteria, it is possible to automatically and objectively separate the soil and the sludge. It can be treated as surplus soil, reducing the amount of industrial waste discharged and the disposal cost.

[0014] The amount of solids to be separated also changes according to the change in the soil properties of the excavated object at the face, but based on the result of the discrimination, segregated transport means for transporting the soil and sludge to the respective storage means. Thereby, sediment and sludge can be continuously separated.

Therefore, the muddy water can be transported efficiently without adversely affecting the excavation work.

Further, it is preferable that the discriminating means includes a moisture meter for detecting a state of adhering moisture of the solid.

For example, as the moisture meter, a light source that emits a first light beam to irradiate an object to be measured and a second light beam for correction, and passes the first and second light beams. A specific narrow-band filter, a light-collecting unit for receiving and condensing reflected light from the object to be measured, and a detecting unit provided at the light-condensing point, and irradiating the light-condensing point with the second light beam Preferably, the detection unit employs a moisture meter that detects the moisture adhesion state.

According to this, by passing the light through the specific narrow band filter, the light beam can be adjusted to a more accurate wavelength. In addition, by irradiating the detection unit with the second light beam, it is possible to accurately detect the reflected light without being affected by the temperature change of the reflected light. As a result, it is difficult to be affected by the color, distance, temperature, and the like of the solid content, which is the measurement object, and accurate determination can be made.

Here, the light beam is preferably, for example, a near infrared light beam.

Further, it is preferable that the separating means includes means for separating coarse particles having a particle size of 75 μm or more from the excavated earth and sand as the solid content.

According to this, the solid content has a particle size of 75 μm.
m or more, and the particle size is limited, so that sediment and sludge can be easily separated. As such a separating means, for example, a vibration sieve, a liquid cyclone, or the like is applicable.

Further, it is preferable that the separation means includes an attached muddy water removing means for removing muddy water attached to the solid content.

According to this, by removing the adhering mud, it is possible to accurately detect the state of water adhering to the surface of the solid, and to properly discriminate the solid which has conventionally been blindly discriminated as sludge. It is possible to do.

Here, as the attached muddy water removing means, for example, means for removing the attached muddy water by blowing off the attached muddy water with air or water can be applied.

Further, it is preferable that the separating means includes a vibrating sieve, and a solid content not passing through a mesh of the vibrating sieve is sent to the discriminating means.

According to this, by measuring a limited measuring object such as the size of solid matter that does not pass through the mesh of the vibrating sieve, a correction process or the like according to the size can be performed, and accurate determination can be made. be able to.

In particular, since the size of the mesh applied to the vibrating sieve is adjusted according to the soil characteristics of the excavation target, particularly, the distribution of the grain soil, correction processing or the like in accordance with the size of the mesh is performed. By doing so, accurate determination can be made regardless of the soil quality of the excavation target.

Further, a first flow rate measuring means for measuring a flow rate of the pre-separation mud containing the excavated earth and sand before being introduced into the separation means, and a post-separation after the solid content is separated by the separation means. A second flow rate measuring means for measuring the flow rate of the muddy water, and a soil amount of the solid content is calculated based on a difference between a measurement result of the second flow rate measuring means and the first flow rate measurement result. It is preferable to include control means for performing at least one of excavation control and muddy water transport control so as to increase the amount of the sediment recovered based on the result.

According to this, the soil amount of the solid, that is,
It is possible to confirm and verify whether the actual solid recovery amount satisfies the design value.

[0030] Preferably, the control means includes means for controlling advance / retreat of a preceding bit of the excavator as the excavation control.

According to this, for example, a plurality of preceding bits are moved forward and backward by using a jack, and the ground protruding portion during the streak excavation between the preceding bits is determined by using the following bit (main bit). By cutting and excavating, the size of excavated earth and sand to be excavated can be adjusted.

This makes it possible to adjust the size of the excavated earth and sand to a size that allows fluid transport (does not block the sludge pump and the like), and it is possible to efficiently perform excavation and fluid transport.

Preferably, the control means includes means for controlling the amount of the dissolution inhibitor added to the mud sent to the separating means as the mud transport control.

According to this, by adding the dissolution inhibitor to the muddy water, the amount of excavated earth and sand dissolved in the muddy water can be reduced, and more solid content can be recovered. Further, by controlling the amount of the dissolution inhibitor based on the measurement result, the amount of the dissolution inhibitor added can be suppressed to the minimum necessary.

Further, the method for separating sediment according to the present invention includes a transporting step of transporting excavated sediment generated by excavation using muddy water, and a step of transporting the muddy water containing the excavated sediment to a solid having a predetermined size and the solid content. A separating step of separating the solid into muddy water containing fine particles other than fine particles, a detecting step of detecting the state of adhesion of the separated solid to water, and a determination of determining whether the solid is soil or sludge based on the detection result. And a step.

According to the present invention, earth and sand and sludge can be automatically and objectively determined by determining the state of adhesion of solid moisture. That is, if the degree of adhesion of moisture is high, it is discriminated as sludge, and if the degree of adhesion of water is low, it is discriminated as earth and sand, and classification is possible.

As a method of this discrimination, specifically, a relative discrimination method of discriminating as sludge if the water content is higher than the natural water content of the ground, or, for example, using a water content of 65% as a reference value, If the water content is higher than the reference value, an absolute discrimination method of discriminating sludge can be adopted.

In the latter case, the reference value may be changed between about 40% and 65% in accordance with the soil characteristics of the object to be excavated.

Since sediment and sludge can be separated,
The earth and sand that has been conventionally treated as sludge can be treated as construction residual soil, thereby reducing the amount of industrial waste discharged and the treatment cost.

Here, the predetermined size corresponds to, for example, a particle size of 75 μm or more.
“A particle size of 75 μm or more” is a value serving as a reference for separating coarse particles in a primary treatment facility for general muddy water.

It is preferable that the method further includes a step of removing muddy water adhering to the solid content prior to the detecting step.

According to this, by removing the adhering muddy water, the state of adhering moisture on the surface of the solid can be accurately detected.

[0043]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments to which the present invention is applied will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is a schematic view of a muddy shield excavation system according to an example of the present embodiment.

The muddy water shield excavating system has a face 46.
Excavator 34 for excavating soil, a face stability management system 58 for adding a thickener or the like to mud to stabilize the face, a mud feeding system 43 having a muddy water supply path, and muddy water mixed with sediment after excavation. And a ground facility 30 for performing solid-liquid separation and the like of the wastewater sent from the wastewater system 47.

The excavator 34 has a face 46 which is a part of the ground.
Disc 40 that cuts through, a partition wall 41 that prevents infiltration of muddy water and excavated earth and sand, a cutter disk 40 and a partition wall 4
1 and a chamber 42 filled with muddy water to stabilize the face.

With the progress of the excavator 34, the soil quality of the face 46 changes. For example, when the ground is mainly composed of cohesive soil, the ground is mainly composed of sandy soil. The nature of the mud will also change.

The mud feed system 43 includes a mud feed pipe 44 which is a mud feed path from the ground equipment 30 to the excavator 34, and a mud feed pump 96 which pressurizes muddy water and sends it to the chamber 42. You.

The face stability management system 58 includes the excavator 34
This is a system for stabilizing the face 46 in real time by adding a thickener, a plugging agent, etc. to the muddy water in accordance with the properties of the face 46.

The face stability management system 58 is provided in the filling agent tank 50, the thickening agent tank 51, and the mud feed pipe 44, and is provided with the filling agent or the thickening agent tank 50 supplied from the filling agent tank 50. And a static mixer 54 for evenly dispersing the thickener supplied from the muddy water.

The sludge exhaust system 47 is provided in the sludge pipe 48, which is a transportation path for the sludge water after excavation of the face from the excavator 34 to the ground equipment 30, and is mixed with the excavated earth and sand of the face 46. A sludge pump 98 which pressurizes and sends the discharged sludge water;
The muddy water sent from the sludge pump 98 is pressurized and the shaft 32
And a relay pump 97 for sending the air to the ground via the relay pump 97.

The muddy water treatment in the ground equipment 30 includes:
There are mainly a primary treatment in the primary treatment equipment 26 for separating coarse particles having a particle diameter of 75 μm or more, and a secondary treatment by the secondary treatment equipment 28 for treating fine particles having a particle diameter of 74 μm or less. .

The primary processing in the primary processing equipment 26 is divided into preprocessing and main processing. The pre-treatment is used for the purpose of reducing the burden of the present treatment, and in particular, to separate and remove solids such as large-diameter gravel and solidified clay from wastewater.

Here, the solid content means a particle size of 75 μm.
It means a viscous soil mass excavated in a lump having a particle size of 75 μm or more while retaining the above coarse fraction (generally classified as sand or gravel) and the structural skeleton in the ground state.

More specifically, the primary pretreatment machine 20 serves as a pretreatment, and the liquid cyclone 17 and the vibrating sieve 4 are provided as a component serving as a main treatment.

From the sludge discharging system 47, the primary treatment equipment 26
Is fed into the primary pre-treatment machine 20, and after large-diameter gravels and clay lumps are separated, is fed into the vibrating sieve 4 and vibrates the upper and lower nets of the vibrating sieve 4, Medium to small diameter gravel or clay lumps not separated by the primary pretreatment machine 20 are separated.

The muddy water after the separation of the gravel and clay lumps is supplied to the liquid cyclone 17, and the muddy water concentrated by the centrifugal action by the rotation of the water flow is sent to the vibrating sieve 4 again. In this way, the mud is separated cyclically. The wastewater from which the solid content of 75 μm or more has been separated by the primary pretreatment device 20, the vibrating sieve 4 and the liquid cyclone 17, which is a separating means, is sent to the adjusting tank 3. On the other hand, the separated solid content of 75 μm or more is not subject to the waste treatment method unlike sludge, and is thus carried out of a treatment facility by a standard dump truck.

The muddy water sent to the adjusting tank 3 is partly reused as muddy water, and partly subjected to dehydration, concentration, reforming, etc. by the secondary treatment equipment 28. The waste is transported to a disposal site by a transport vehicle, and part of it becomes filtered water after dehydration and used as dilution water.

Next, the primary processing equipment 2 according to the present embodiment
6 will be described in detail.

FIG. 2 is a schematic diagram of a primary processing facility 26 according to an example of the present embodiment.

The primary pretreatment machine 20 is provided with a mesh-shaped rotary drum 172 serving as a solid content separation path, a motor 170 for rotating the rotary drum 172, and a mesh below the rotary drum 172. And a tank 176 for temporarily storing the passing muddy water.

The wastewater is supplied from the wastewater system 47 to the pipe 142.
Is sent to the primary pre-processing machine 20 via the. Rotating drum 17
2 has a discharge port at one end, and a discharge port for separated solid at the other end. The supply port is located at the discharge port so that the waste water flows from the supply port to the discharge port by its own weight. It is provided at the upper position.

That is, of the muddy water supplied to the supply port, the solid matter having a larger particle size than the mesh of the rotary drum 172 moves on the mesh in the rotary drum 172 and is discharged from the discharge port by its own weight. On the other hand, wastewater containing solids having a smaller particle size than the mesh of the rotating drum 172 passes through the mesh of the rotating drum 172 and is stored in the tank 176.

The muddy water stored in the tank 176 of the primary pretreatment machine 20 is pumped toward the vibrating sieve 4 via a pipe 140 by a pump 90 provided near the bottom of the tank 176.

The solid recovery by the primary pretreatment machine 20 is adjusted by rotating the rotary drum 172 and supplying washing water to the vicinity of the muddy water supply port to the rotary drum 172. The reason for supplying the washing water is that the fine particles attached to the coarse solids contained in the muddy water are washed away and the clogging of the mesh is prevented, so that the coarse solids are efficiently collected. That's why.

The cleaning water is supplied into the rotary drum 172 from the nozzle at the tip of the pipe 146 near the above-mentioned supply port by the pump 92 for pumping the cleaning water sent from a cleaning water tank (not shown) through the pipe 146. Is done. The motor 170 and the pump 92 are controlled by the control device 180.

The solids that have not passed through the mesh of the rotating drum 172 are sent to the primary treated soil storage device via the drum chute 178.

The washing water supplied to the rotating drum 172 is temporarily stored in a tank 176 together with the muddy water containing fine particles.

The muddy water after the completion of the pretreatment is sent to the vibrating sieve 4 for the main treatment. The vibrating screen 4 includes an upper screen 6 and a lower screen 8.
And a motor 171 for vibrating the upper net 6 and the lower net 8. Normally, the mesh of the lower net 8 is formed larger than the mesh of the upper net 6, and is smaller than the mesh of the rotary drum 172 when the temporary pre-processing device 20 is used.

The size of the mesh of the temporary pretreatment device 20 and the vibrating sieve 4 is appropriately set according to the distribution of solid soil in the ground and the solid recovery rate. Specifically, for example, the mesh of the rotating drum 172 of the temporary pretreatment machine 20 is 20 to 40 mm, the mesh of the lower net 8 of the vibrating sieve 4 is 5 to 40 mm, and the mesh of the upper net 6 of the vibrating sieve 4 is 0.1 to 40 mm. It is good to make it about 1.0 mm.

The wastewater is introduced into the lower net 8 through the pipe 140, and the solids that have not passed through the mesh of the lower net 8 are sent to the sediment separating apparatus 10 through the lower net chute 82.

On the other hand, the muddy water that has passed through the mesh of the lower net 8 is stored in the tank 14 and sent to the liquid cyclone 17 through the pipe 148 by the pump 93.

The mud introduced into the hydrocyclone 17 is
Due to the diameter of the liquid cyclone 17 and the centrifugal separation, muddy water containing particles having a particle diameter of 75 μm or more is introduced into the upper screen 6 of the vibrating sieve 4 as under muddy water. Is sent to the adjustment tank 3 through the pipe 149.

Of the muddy water fed into the upper net 6 of the vibrating sieve 4, the earth and sand that has not passed through the mesh of the upper net 6 is sent to the primary treated soil storage device through the upper net chute 80.

On the other hand, the muddy water that has passed through the mesh of the upper net 6 is stored in the tank 14 and sent to the liquid cyclone 17 through the pipe 148 by the pump 93.

In this way, the solid content of the wastewater is separated and sent to the sediment separating apparatus 10.

FIG. 3 is a schematic diagram of a sediment separating apparatus 10 according to an example of the present embodiment.

The sediment separating apparatus 10 detects a state of water adhering to solids that have not passed through the mesh of the lower net 8, and is a moisture meter which is a discriminating apparatus for discriminating whether the solid is soil or sludge based on the detection result. 110, and a belt conveyor 112, which is a separating device for separating earth and sand from the solid content as earth and sand and separating sludge as sludge based on the determination result.

The moisture meter 110 discriminates sludge if the degree of adhesion of solid water is high, and discriminates sediment if the degree of adhesion of water is low. As a method of this determination,
Specifically, a relative discrimination method for discriminating sludge when the water content is higher than the natural water content of the ground, or, for example, when the water content is 65% as a reference value and the water content is higher than the reference value An absolute discrimination method of discriminating as sludge can be adopted.

In the latter case, the reference value may be changed between about 40% and 65% or a correction process may be performed according to the soil characteristics of the object to be excavated.

In the sediment separating apparatus 10, the lower screen 8 of the vibrating sieve 4
By measuring a limited measurement target such as the size of a solid content that does not pass through the mesh, correction processing or the like according to the size can be performed, and accurate determination can be made.

In particular, since the size of the mesh applied to the vibrating sieve 4 is adjusted according to the soil characteristics of the excavation target, particularly, the distribution of the granular soil, the mesh of the lower mesh 8 is By performing a correction process or the like in accordance with the size of the excavation, it is possible to accurately determine the excavation target regardless of the soil properties.

When the solid content is determined to be earth and sand, the belt conveyor 112 rotates to the left in FIG. 3 and sends the earth and sand to the primary processing soil storage device which is the earth and sand storage means. When the solid content is determined to be sludge, the belt conveyor 112 rotates rightward in FIG.
Is sent to the secondary treatment soil storage device, which is a sludge storage means in the country.

As described above, the soil of the face 46 changes, and as a result, the soil of the solid separated by the separating means also changes. According to the present embodiment, the moisture content of the solid content can be continuously detected and determined by the moisture meter 110, and can be continuously separated by the belt conveyor 112. For this reason, even if the separation is performed, the separation processing can be continuously performed without adversely affecting the excavation such as stopping or delaying the excavation.

Next, the principle of the moisture meter 110 will be described.

FIG. 4 is a principle diagram of a moisture meter 110 according to an example of the present embodiment.

The moisture meter 110 includes a light source 200 that emits a first light ray 260 for irradiating a solid content as an object to be measured 250 and a second light ray 262 for correction, a first light ray 260 and a second light ray Specific narrow band filter 2 that passes light beam 262
10, a light-collecting unit 220 that receives and condenses the reflected light from the device under test 250, and a detection unit 240 that is provided at the light-condensing point and detects the state of solids adhering to water. You.

Further, the first light ray 260 is
The second light ray 262 is formed so as to be reflected by the light source and irradiate the device under test 250, and to be reflected by the reflection units 232 and 234 and irradiated to the detection unit 240 which is a condensing point.

Here, a near-infrared ray is used as the first ray 260 and the second ray 262. Moisture has the property of absorbing near-infrared light of a specific wavelength. Since near-infrared light is absorbed in proportion to the water content of the substance, it can be quantified.

According to this, by judging the adhesion state of water using a moisture meter using near infrared rays, it is hard to be affected by the color, distance, temperature, etc. of the solid of the object to be measured 250, and accurate. Can be determined.

Further, the light beam can be adjusted to a more accurate wavelength by passing through the specific narrow band filter 210.

Further, not only the first light ray 260 for measurement, but also the second light ray 262 for irradiating the detection unit 240 for correction is emitted. By irradiating the detection unit 240 with the second light beam, it is possible to accurately detect the reflected light without being affected by a change in temperature of the reflected light. As a result, it is hard to be affected by the color, distance, temperature, and the like of the solid content, which is the object to be measured, and can be accurately determined.

Based on the state of adhesion of the solid content thus detected, if the degree of adhesion of water is high, it can be determined as sludge, and if the degree of adhesion of water is low, it can be determined as earth and sand.

As a means for removing the attached muddy water from the vibrating sieve 4, a pipe 144 serving as a path for supplying washing water from the washing water tank (not shown) to the inside of the vibrating sieve 4, A pump 94 for pumping water is provided.

According to this, by removing the adhering mud, it is possible to accurately detect the state of water adhering to the surface of the solid, and the solid which has conventionally been blindly discriminated as sludge can be properly discriminated. It is possible to do.

The pumps 92 and 94 for supplying the washing water
Is driven and controlled by the control device 180 so that cleaning water can be supplied only when cleaning is necessary. Further, the drive of the motor 170 is controlled by the control device 180 and the rotation speed of the rotary drum 172 is controlled, so that the amount of the recovered solid is finely adjusted.

Next, the flow of the muddy water based on the above configuration will be described.

FIG. 5 is a schematic diagram showing the flow of muddy water in the muddy water treatment equipment according to an example of the present embodiment.

[0099] Wastewater discharged from the shaft 32 to the ground by the wastewater system 47 is sent to the primary pretreatment machine 20.
In the primary pretreatment machine 20, large-diameter gravel and the like are removed by the rotating drum 172. The removed gravel can be handled as earth and sand.

The wastewater containing solid matter such as large-sized sand and gravel is introduced into the vibrating sieve 4. In vibrating sieve 4, lower mesh 8
Removes more than 40 mm of solids. The removed solid content is determined by the sediment separation apparatus 10 as soil or sludge.

The mud from which the solid content exceeding 40 mm has been removed by the lower screen 8 is further removed by the upper screen 6 from which the sand content exceeds 0.5 mm. The removed sand is treated as earth and sand.

In the sediment separating apparatus 10, the moisture meter 11
According to 0, the solid content is determined to be sludge if the degree of adhesion of moisture is high, and is determined to be earth and sand if the degree of adhesion of water is low.

When the solid content is determined to be sludge, the solid content is conveyed by the belt conveyor 112 to the secondary treatment soil storage device of the secondary treatment equipment 28. When the solid content is determined to be earth and sand, the solid content is conveyed by the belt conveyor 112 to the primary treated soil storage device.

The muddy water that has passed through the lower screen of the vibrating sieve 4 is introduced into the liquid cyclone 17, and the excess muddy water from the liquid cyclone 17 is sent to the adjusting tank 3.

The wastewater sent from the adjusting tank 3 to the secondary treatment equipment 28 is subjected to reforming, dewatering, etc., and is treated as sludge.

As described above, according to the present embodiment, since the water-containing state is detected and separated into sediment and sludge, the excavated sediment which has been blindly treated as sludge in the past is the original form of sediment. As a result, the discharge amount of industrial waste can be reduced, and the processing cost can be reduced.

Next, a description will be given of an embodiment in which solids are collected in a lump while excavating a hard clay layer while maintaining the strength of the ground as much as possible.

(Second Embodiment) In the muddy water treatment system described in the first embodiment, when recovering solids, a vibrating sieve, a cyclone, a primary pretreatment machine having a rotating drum, and the like are usually used. The collected solids are accumulated in the sediment hopper. It is necessary to accurately measure the amount of solid recovered in order to optimally control the excavator and minimize the amount of chemicals added to the muddy water for stabilizing the face.

However, conventionally, the amount of solids collected was measured by the earth and sand hopper and the amount of solids sent from the earth and sand hopper to the belt conveyor, so that the measurement was not accurate and the measuring device was also large.

If the amount of solid dissolved in the muddy water can be measured at the same time as the amount of solids recovered, the amount of the dissolution inhibitor added to the muddy water can be controlled by controlling the amount of the dissolution inhibitor based on the measurement result. The volume can be kept to a minimum.

FIG. 6 is a schematic diagram of a primary processing facility according to another example of the present embodiment.

In the present embodiment, in addition to the configuration shown in FIG. 2 described in the first embodiment,
A flow meter 162 is provided for measuring the flow rate of the wastewater before separation including the excavated earth and sand sent to the pipe. The pipe 140 measures the flow rate of the wastewater after solid recovery (after separation) in the primary pretreatment machine 20. A flow meter 160 is provided.

The flow rate measured by the flowmeter 162 and the flowmeter 16
By determining the difference from the flow rate measured at 0, the amount of solids recovered by the primary pretreatment machine 20 (the amount of collected solids) can be determined.

A flow meter 166 is also provided on a pipe 149 through which the over muddy water classified by the hydrocyclone 17 flows.

The flow rate measured by the flowmeter 160 and the flowmeter 16
By determining the difference from the flow rate measured in 6, the amount of solid collected in the primary treatment facility can be determined.

The control device 180 functions as a calculation means for performing a predetermined calculation based on the flow rate measurement result, and also obtains the solid recovery amount and performs various controls.

Further, as shown in FIG. 1, a flow meter 70 is provided in the sludge pipe 48 in the vicinity of the face 46, and after the elapse of the flow meter 70, the solid content in the waste water is dissolved. The dissolution inhibitor, which is a chemical for preventing the dissolution, is formed so as to be mixed in from the dissolution inhibitor tank 52. In addition, it is also possible to form so that the dissolution inhibitor may be mixed in the muddy water flowing from the dissolution inhibitor tank 52 through the mud pipe 44.

Further, a flow meter 164 for measuring the flow rate of the washing water in the primary pretreatment machine 20 is provided on a pipe 146 for supplying the cleaning water to the primary pretreatment machine 20. In addition, a flow meter 16 for measuring the flow rate of the washing water in the primary treatment machine.
Numeral 8 is provided on a pipe 144 for supplying washing water to the vibrating sieve 4 which is a part of the primary treatment machine. In addition, these flowmeters 1
For 60 to 168, a generally used flow meter can be applied.

As shown in FIG. 6, it is preferable that the flow meter 160 and the flow meter 162 are provided as close to the primary pretreatment machine 20 as possible. Further, it is preferable that the flow meter 166 is also provided at a position close to the liquid cyclone 17. By providing the flow meter 166 at a position close to the hydrocyclone 17, there is almost no time lag at the time of solid recovery and at the time of measuring the flow rate of the wastewater, so that the solid content can be accurately measured.

Next, a description will be given of a processing procedure in the case of performing the measurement of the solid recovery amount and various controls for increasing the solid recovery rate by using these means.

FIG. 7 is an example of a flowchart showing the flow of the measurement and control of the solid recovery amount.

First, the primary pretreatment machine 2
0, that is, the flow rate V of the muddy water before separation
1 is obtained (step 1). Also, the flow rate V of the cleaning water
2 is a flow meter 164 provided in a pipe 144 which is a washing water flow path between the pump 92 and the rotary drum 172, and a flow rate provided in a pipe 144 which is a washing water flow path between the pump 94 and the vibrating sieve 4. It is measured using a total 168 (step 2).

The flow rate of the over-muddy water classified by the hydrocyclone 17, that is, the flow rate V3 of the separated muddy water is measured using the flow meter 166 (step 3).

V1, V2,
The solid recovery amount V is obtained from V3. The calculation formula is V = V
1 + V2−V3, which is obtained by the controller 180 (step 4).

In this manner, the solid recovery amount V can be determined. As can be seen from this equation, even when washing water is added to the muddy water containing solids, the calculation can be performed in consideration of the amount of washing water added, so that the solid recovery amount can be accurately measured.

When the cleaning is not performed, the above equation may be calculated as V = V1-V3.

Further, based on the obtained solid recovery amount V,
It is important to perform a predetermined control in order to improve the face stability and the solid recovery rate.

The calculated solid recovery amount is compared with a desired value by the control device 180 (step 5). If the solid recovery amount is smaller than the desired value, the jack speed of the shield machine 34 and the expansion of the preceding bit that can expand and contract are performed. The amount is increased, the rotation speed of the cutter disk 40 is reduced, the amount of the dispersant to be supplied to the face is reduced, and the pumps 92 and 94 are controlled and supplied to the primary pretreatment machine 20 and the vibrating sieve 4. The amount of washing water is reduced (step 6).

It should be noted that, when the amount of solid recovered is equal to or more than the desired amount, no particular control is required, but it is possible to control as needed.

As described above, by performing the excavation control such as the jack speed control and the advance / retreat control of the preceding bit, the solid recovery amount can be increased, and the maximum solid recovery can be performed before the primary processing. And the muddy water treatment efficiency can be improved.

[0131] Here, the extendable leading bit is a bit for excavating a part of the cutter bit provided on the cutter disk 40 prior to another cutter bit, and is capable of extending and contracting. In other words, it is described in a document filed earlier by the present applicant (Japanese Patent Application Laid-Open No. 8-313293).

By controlling the excavator based on the accurately measured solid recovery amount, the excavator and the like can be more properly controlled for excavation. Thereby, the solid recovery amount can be increased, and the solid recovery rate can be improved. In addition,
As such excavation control, it is preferable to include means for controlling advance / retreat of a preceding bit of an excavator described in a document (for example, Japanese Patent Application No. 11-86045) filed by the present applicant.

According to this, for example, a plurality of preceding bits are advanced and retracted by using a jack, and the ground protruding portion during the streaking and excavation between the preceding bits is determined by using the following bit (main bit). By cutting and excavating, the size of excavated earth and sand to be excavated can be adjusted.

As a result, the size of the excavated earth and sand can be adjusted to a size that is difficult to dissolve during transportation, and the solid recovery amount can be increased.

Further, by controlling the amount of the dispersant added based on the accurately measured solid recovery amount, appropriate muddy water excavation can be performed with a smaller amount of chemicals. Therefore, resource saving and cost reduction can be realized. The same action and effect can be obtained when a drug other than the dispersant, for example, a thickener is added.

Next, a description will be given of a processing procedure for measuring and controlling the amount of solid dissolved, which indicates the amount of solid dissolved in muddy water, using each of the above means.

FIG. 8 is an example of a flowchart showing the flow of measurement and control of the amount of solid solution.

By measuring the solid content dissolved in the muddy water and reducing the dissolution rate, the solid recovery rate can be further improved.

First, the amount of solids contained in the wastewater in the wastewater pipe 48 is measured by the solid flowmeter 70 (step 11). This measurement is based on documents previously filed by the present applicant (JP-A-9-159595 and JP-A-9-15962).
It is preferable to use a measuring device using radio waves described in 3).

This measuring device radiates radio waves to muddy water, receives radio waves propagating through muddy water, calculates the density of solids based on the reception level, and calculates the flow rate of solids from this density. . By using such a measuring device, the solid flow rate can be accurately measured.

This measuring device is used for the solid flow meter 70 shown in FIG. As shown in FIG. 1, the solid flow meter 70 is provided in a drain pipe 48 near the face 46. Thereby, the solid flow rate while passing through the exhaust pipe 48 can be more appropriately measured. Here, the solid flow rate measured by the solid flow meter 70 is defined as V4.

Next, the flow rate V1 of the muddy water is measured by the flow meter 162 (step 12), the flow rate V2 of the washing water is measured by the flow meter 164 (step 13), and the flow rate of the muddy water is measured by the flow meter 166 in the same manner as described above. Measure V3 (Step 1)
4).

Next, the controller 180 calculates the solid dissolution amount V0 (step 15). Here, V0 = V4
− (V1 + V2-V3).

Based on the calculation result, predetermined control is performed using the control device 180. If the solid dissolution amount V0 is larger than the desired value (step 16), the solid content is excessively dissolved in the drainage pipe, so the drainage pump 98 is controlled to reduce the flow rate of the wastewater, The amount of the dissolution inhibitor added from tank 52 to the wastewater is increased (step 17).

When the amount is less than the desired amount, there is no particular need to control, but it is possible to control as needed.

According to the above control system and method,
The amount of solid dissolved in the muddy water while the muddy water flows from the solid flow meter 70 to the primary pretreatment machine 20 can be measured. If the amount of the additive to be added to the muddy water is adjusted based on the measurement result, the optimum excavation can be performed with a smaller amount of the additive.

The control similar to the control performed based on the calculation result of the solid recovery amount may be performed based on the calculation result of the solid dissolution amount. Further, the amount of the additive added to the muddy water may be controlled based on the change in the flow rate of the muddy water after the separation.

As described above, the amount of solid contained in the drilling mud is measured simply and accurately, and based on the obtained solid amount, the primary pretreatment machine, the excavator, the amount of the additive to be added to the mud, etc. Can be appropriately controlled.

By appropriately controlling the amount of the dissolution inhibitor added as described above, it is possible to increase the proportion of the solid content contained in the excavated wastewater that can be recovered as it is, thereby reducing the environmental impact. Can be reduced.

The preferred embodiment to which the present invention is applied has been described above. However, the application of the present invention is not limited to the above-described embodiment.

For example, the moisture meter 110 is
When installed in the interior of the
It is possible to perform the measurement while protecting the moisture meter 10 by providing the moisture analyzer 10 on the upper part.

Further, in the above-described embodiment, the muddy water shield method has been described as an example. However, in addition to the muddy water shield method, various methods using muddy water, such as the reverse circulation method, the underground continuous wall method, and the like. And the like.

As a method for removing the muddy water adhering to the solid content, a method for removing the muddy water by blowing it off with a liquid other than water or air may be employed.

Further, in the above-described embodiment, an example has been described in which the solid recovery amount of both the primary pretreatment device and the vibrating sieve is obtained. However, a flow meter is provided in the flow path between the primary pretreatment device and the vibrating sieve. By measuring the flow rate, it is also possible to obtain the solid recovery amount of the primary pretreatment machine alone or the vibrating sieve alone.

[Brief description of the drawings]

FIG. 1 is a schematic view of a muddy shield excavation system according to an example of the present embodiment.

FIG. 2 is a schematic diagram of a primary processing facility according to an example of the present embodiment.

FIG. 3 is a schematic diagram of a sediment separating apparatus according to an example of the present embodiment.

FIG. 4 is a principle diagram of a moisture meter according to an example of the present embodiment.

FIG. 5 is a schematic diagram showing a flow of muddy water in the muddy water treatment equipment according to an example of the present embodiment.

FIG. 6 is a schematic diagram of a primary processing facility according to another example of the present embodiment.

FIG. 7 is an example of a flowchart showing a flow of measurement and control of a solid dissolution amount.

FIG. 8 is an example of a flowchart showing the flow of measurement and control of the solid recovery amount.

[Explanation of symbols]

 4 Vibrating sieve 6 Upper net 8 Lower net 17 Liquid cyclone 20 Primary pretreatment machine 110 Moisture meter 112 Belt conveyor 160-168 Flow meter 180 Controller

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masago Yasumoto 1-7-1 Kyobashi, Chuo-ku, Tokyo Inside Toda Construction Corporation (72) Inventor Konosuke Nakamura 1-7-1 Kyobashi, Chuo-ku, Tokyo No. Inside Toda Construction Co., Ltd. (72) Inventor Yoshio Iwai 1-7-1, Kyobashi, Chuo-ku, Tokyo Toda Construction Co., Ltd. (72) Satoru Tabata 1-7-1, Kyobashi, Chuo-ku, Tokyo Inside Toda Construction Co., Ltd. (72) Yasushi Fukuda 1-7-1, Kyobashi, Chuo-ku, Tokyo Toda Construction Co., Ltd. (72) Inventor Akio Uraya 3-39-1, Hazawa, Nerima-ku, Tokyo SANE -Industry Co., Ltd. (72) Inventor Masaru Yasukochi 3-39-1, Hazawa, Nerima-ku, Tokyo

Claims (8)

[Claims] An excavation method for transporting excavated earth and sediment in muddy water, comprising: a sediment separation system for separating solid matter separated from wastewater containing excavated earth and sand by predetermined separating means into sediment and sludge. A detecting means for detecting the state of water adhesion of the solid content, and discriminating whether it is soil or sludge based on the detection result, and, based on the discrimination result, transporting the solid content discriminated as sediment to the sediment storage means, and A separating and conveying means for conveying the discriminated solid matter to a sludge storing means. 2. The sediment separation system according to claim 1, wherein the separation means includes an attached muddy water removing means for removing muddy water attached to the solid content. 3. The sediment separation system according to claim 1, wherein the separation unit includes a vibrating sieve, and sends a solid content that does not pass through a mesh of the vibrating sieve to the determination unit. . 4. The flow rate measuring apparatus according to claim 1, wherein the first flow rate measuring means measures a flow rate of the pre-separation mud containing the excavated earth and sand before being introduced into the separating means. A second flow rate measuring means for measuring a flow rate of the separated muddy water after the solid content is separated; and a second flow rate measuring means based on a difference between a measurement result of the second flow rate measuring means and a measurement result of the first flow rate measuring means. Calculating the amount of soil in the solid, based on the result of the calculation, control means for performing at least one of excavation control and muddy water transport control so as to increase the amount collected as the soil and sand. Sediment separation system. 5. The sediment separation system according to claim 4, wherein the control means includes means for controlling advance / retreat of a preceding bit of the excavator as the excavation control. 6. The sediment separation method according to claim 4, wherein the control means includes means for controlling an amount of a dissolution inhibitor added to the muddy water sent to the separating means as the muddy water transport control. system. 7. A transporting step of transporting excavated earth and sand generated by excavation using muddy water, the muddy water containing excavated earth and sand is mixed with muddy water containing a solid of a predetermined size and fine particles other than the solid. A separation step of detecting the state of adhesion of the separated solid to water, and a determination step of determining whether the solid is soil or sludge based on a detection result. Sediment separation method. 8. The method for separating sediment according to claim 7, comprising a step of removing muddy water adhering to the solid matter prior to the detecting step.