JPH10338931A - Sludge withdrawal treatment method of high-pressure jet mixing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To treat sludge generated by a high-pressure jet mixing method at low cost. SOLUTION: In the high-pressure jet mixing method, grout is high-pressure injected into a ground 6 through an injected rod 1 while lowering or lifting the injection rod 1 into the ground 6 by rotation, and an improved body is prepared. Slurry discharged into a slime bit 53 through the periphery of the injection rod 1 during the execution of the high-pressure jet mixing method is forwarded to a raw water tank 66 through a vibration screen 67 first at that time, slurry in the raw water tank 66 is force-fed into a cyclone 70, gravel is separated from slurry, separated gravel is conveyed out to the outside of a system through a vibrating type dehydrator 73 from one end of the cyclone 70 and used as a construction material, a residual liquid separated in the cyclone 70 is sent to a slurry tank 62 having a built-in agitator 78 through a relay tank 63 from the other end of the cyclone 70, the concentration of a hardener for the residual liquid is adjusted, and the residual liquid is reused as grout.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating sludge generated by a jet grout method which is one of ground improvement methods.

[0002]

2. Description of the Related Art The jet grouting method is a method in which a grout containing a hardener is injected under high pressure into the ground through the injection rod while rotating or lowering the injection rod into the ground to form an improved body. In recent years, it has been widely used for ground improvement because a large diameter improved body can be formed only by making one round trip.

As the jet grouting method, a single pipe method in which only a grout is injected at a high pressure by using a single pipe rod by selecting an injection rod (see Japanese Patent Publication No. 48-25768) or a double pipe rod is used. Double-pipe method in which grout and air are mixed and injected (see Japanese Patent Publication No. 56-44206, etc.), and the ground is cut and stirred by high-pressure injection of air and water using a triple pipe rod. A triple tube system in which grout is injected at high pressure into the layer (Japanese Patent Publication No. 58-2736)
No. 4, publication No. 4, etc.), and any of them is adopted depending on the properties of the improved ground, the scale of the improvement, and the like.

[0004]

In this type of jet grout method, the ground is cut and stirred over a wide area by high-pressure injection of grout (and air or water), so that a large amount of excess slime (muddy water) is generated. The mud is then discharged to the ground through the dosing rod. Therefore, when implementing the jet grouting method, how to treat the muddy water (discharged mud) discharged to the ground is an important issue. However, as described above, the muddy water was disposed in a nearby place because of its large amount. Even if it is stored in a tank, it becomes full early. Therefore, conventionally, pitch transported by a vacuum truck and dumped as industrial waste in an appropriate sedimentation basin, but it is quite difficult to secure the sedimentation basin described above due to recent land conditions, environmental conditions, etc. However, there is a problem that the transportation distance by the vacuum vehicle is further increased, and that the above-mentioned sludge treatment requires a large cost.

[0005] In some cases, the muddy water is supplied to a filter press to be dewatered and then discarded.
Since a large amount of a hardening agent composed of fine particles is present in the muddy water, the filter is clogged at an early stage, and the use of the filter has to be practically abandoned.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to separate sand and gravel from muddy water generated by the jet grouting method and to reuse the sand and gravel to thereby discharge sludge. An object of the present invention is to significantly reduce costs required for processing.

[0007]

In order to solve the above-mentioned problems, the present invention sends mud water generated by a jet grouting method to a raw water tank through a screen, and discharges the muddy water to a ground through an injection rod during construction of the improved body. The muddy water to be sent to the raw water tank through the vibrating sieve, and further, the muddy water in the raw water tank is sent into the cyclone at a high speed, centrifugal force is used to separate the gravel from the muddy water, and then separated by the cyclone. It is characterized in that the concentration of the curing agent in the muddy water is measured, and the concentration of the curing agent is adjusted based on the measurement result, and thereafter, this is reused as grout.

In such a sludge treatment method, a large amount of sand and gravel occupying a large proportion of the sludge is separated and removed by a cyclone, whereby muddy water having a high hardener concentration is obtained. Can be reused as grout by measuring the concentration and adjusting the concentration appropriately.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIGS. 2 to 4 show one embodiment of the jet grouting method to which the present invention is applied. This jet grouting method includes an injection rod 1 having a double pipe structure, which will be described in detail later, a self-propelled construction machine 2 and a construction plant 3. The construction machine 2 includes an injection rod 1
And a leader 5 equipped with a rotating / elevating unit 4 for supporting the device. The leader 5 is placed upright on the ground 6 during construction. The injection rod 1 is detachably supported by a rotating / elevating unit 4 that moves up and down along the vertically erected reader 5, and rotates or descends according to its operation. A double pipe swivel 7 is attached to the upper end of the injection rod 1, and a high pressure pump 8 and an air compressor 9 in the construction plant 3 are connected to the double pipe swivel 7 by piping.

In the construction plant 3, in addition to the high-pressure pump 8 and the air compressor 9, a water tank 10, a cement silo 11, a grout mixer 12, and the like are installed.
The grout mixer 12 has a function of stirring and mixing the cement (hardening agent) taken in from the cement silo 11 and the water taken in from the water tank 10 to produce grout (cement milk). The admixture is supplied from the admixture tank 13. The water tank 10 and the grout mixer 12 are provided with the high-pressure pump 8
Are connected to each other via a switching valve 14, and the operation of the switching valve 14 selectively supplies water or grout to the high-pressure pump 8. The high-pressure pump 8 is
From 20 MPa (about 100 ~200kgf / cm ²⁾ about a high-pressure water,
In addition to the function of producing ultra-high pressure water of about 35 to 45 MPa (about 350 to 450 kgf / cm ² ), it has a function of producing high pressure grout of about 35 to 45 MPa. Either ultra high pressure water or high pressure grout is selectively supplied. In addition, 15 is a generator as a power source of the construction plant 3.

As shown in FIG. 3, the injection rod 1 has a rod body 22 having a double tube structure having an outer tube 20 and an inner tube 21, and an injection head 23 connected to the rod body 22. It is schematically composed of The high pressure pump 8 in the construction plant 3 is connected to the first flow path a in the inner pipe 21 constituting the rod body 22 through the double pipe swivel 7, while the outer pipe 20 and the inner pipe are connected. An air compressor 9 in the construction plant 3 is connected to the annular second flow path b between the air compressor 9 and the pipe 2 via a double pipe swivel 7.

The injection head 23 has an upper head portion 25 provided with a plurality of double nozzles 24 on the side and a drill bit 2 at the tip.
6 and a lower head portion 27 provided with the same. The upper head portion 25 has a double tube structure including an outer cylinder 28 and an inner cylinder 29, and an annular passage c is formed between the outer cylinder 28 and the inner cylinder 29. The lower portions of the outer cylinder 28 and the inner cylinder 29 are closely fitted to each other, and the bottom of the annular passage c is closed at the fitting portion. A first nozzle unit 30 forming the double nozzle 24 is screwed and fixed to the outer cylinder 28, and a second nozzle unit 31 similarly forming the double nozzle 24 is screwed to the inner tube 29. . The second nozzle unit 31 is extended across the annular passage c, and its tip is inserted into the first nozzle unit 30. A gap of a predetermined size is secured between the first nozzle unit 30 and the second nozzle unit 31, and therefore, the double nozzle 24 is provided at the center thereof with the injection leading to the passage d in the inner cylinder 29. The hole has a structure in which an injection hole around the annular passage c is independently provided.

The upper head portion 25 is connected to the rod body 22 by screwing the outer cylinder 28 to the outer tube 20 of the rod body 22. In this connected state, the upper body 25 is attached to the upper end of the inner cylinder 29. The inner tube 21 is fitted in a liquid-tight manner via a seal member 32. Therefore, the first flow path a in the rod body 22 passes through the passage d in the inner cylinder 29 to the injection hole on the core side of the double nozzle 24, and the second flow path b in the rod body 22 Through the annular passage c, it communicates with the injection holes outside the double nozzle 24 respectively.

The upper head portion 25 is also connected to the lower head portion 27 by screwing the outer cylinder 28 to the main body 33 of the lower head portion 27. In this connected state, the inner cylinder 29 is connected to the lower head portion 27. The upper end of the main body 33 is liquid-tightly butted with a seal member 34 interposed therebetween. The main body 33 of the lower head portion 27 has a communication passage e therein communicating with a passage d in the upper head portion 25, and has a tapered shank portion 3 of the drill bit 26 at the lower end thereof.
5 has a tapered screw hole 33a.

The drill bit 26 is provided at the tip end of the main body 3.
6, a plurality (three in this case) of cutting edges 3 equally distributed in the circumferential direction
7 is provided, and one inclined nozzle 38 is provided inside the cutting blade 37. The inclined nozzle 38 is attached to an inclined hole 39 formed in the main body 36 such that the axis thereof intersects the axis of the injection rod 1 at a predetermined angle θ. Shank 35 and body 36 of drill bit 26
Inside the communication passage e in the main body 33 of the lower head portion 27
Is formed in a series of communication holes 40 which communicate with the inclined hole 39. Therefore, the pressurized fluid is formed in the inclined nozzle 38 through the first flow path a in the nozzle body 22 and the passage d in the injection head 23. (Water or grout). Thus, the diameter of the inclined nozzle 38 is set so as to have substantially the same flow passage area as the injection hole on the core side of the double nozzle 24. Thereby, the injection head 2 is now passed through the first flow path a of the nozzle body 22.
When the pressurized fluid is pressure-fed to the passage d in 3, the pressurized fluid is commonly ejected from the double nozzle 24 and the inclined nozzle 38. The inclination angle θ of the inclined nozzle 38 is set to an appropriate value according to the diameter of the drill bit 26 and the pressure of the high-pressure water.

At the time of construction, the injection rod 1 composed of the rod body 22 and the injection head 23 is supported by the rotating / elevating unit 4 of the construction machine 2 in the mode shown in FIG. The high pressure pump 8 and the air compressor 9 in the construction plant 3 are connected to the double pipe swivel 7 at the upper end. After completion of the preparation, the set pressure of the high-pressure pump 8 is adjusted, and high-pressure water (1
(About 0 to 20 MPa), and while the high-pressure water is ejected from the double nozzle 24 on the side of the injection head 23 and the inclined nozzle 38 at the tip thereof, the rotating / elevating unit 4 is operated to move the injection rod 1 into the ground. Rotate down during 6. Thereby, the ground 6 is cut by the high-pressure water jetted from the double nozzle 24 and the inclined nozzle 38, and at the same time, is mechanically cut by the drill bit 26. Drilling can be performed quickly and efficiently. Further, since the drill bit 26 is cooled by water, its wear is suppressed. In addition, the high-pressure water spouted from the inclined nozzle 38 is diffused in front of the drill bit 26 according to the rotation of the injection rod 1 and preliminarily cuts the front area thereof. The soil is crushed in advance, and problems such as adhesion of the viscous soil to the drill bit 26 and hindering its cutting ability are also solved.

[0018] Thus, during ground 6, a hole 51 of slightly larger diameter than the diameter of the drilling bit 26 as shown in FIG. 4 is formed, the drilling stroke, planning improvements range upper limit D _U
At this point, the set pressure of the high-pressure pump 8 is adjusted, and the high-pressure water to be pumped to the first flow path a in the injection rod 1 is switched to ultra-high-pressure water (about 35 to 45 MPa). High-pressure (686 to 980 kPa... 7 to 10 kgf / cm ² ) compressed air is pumped from the compressor 9 to the second flow path b in the injection rod 1. Ultra-high-pressure water (mixed fluid) with air is jetted from the double nozzle 24 of the injection head 23 by the pressure-feeding of the ultra-high-pressure water to the first flow path a. The inside is strongly cut and stirred.
As a result, a large-diameter cutting and stirring layer 52 is formed in the ground 6, and the cutting and stirring layer 52 gradually expands downward as the injection rod 1 rotates downward. The surplus slime (muddy water) generated at this time is removed from the holes 5 formed in the drilling process.
The sludge is discharged to the slime pit 53 on the ground through 1 and further sent to a sludge treatment system described later.

When the cutting and stirring layer 52 is formed by the cutting and stirring described above, that is, when the cutting and stirring process reaches the lower limit D _{L of the} planned improvement area, the switching valve 14 in the construction plant 3 is switched to the grout mixer 12 to perform injection. The grout of high pressure (about 35 to 45 MPa) is pumped into the first flow path a in the rod 1, and the injection rod 1 is moved while the compressed air is continuously fed to the second flow path b in the injection rod 1. Rotate up. Thereby, high-pressure grout (mixed fluid) accompanied by air is injected from the double nozzle 24 of the injection head 23, and high-pressure grout is jetted from the inclined nozzle 38, and the grout is injected into the cutting and stirring layer 52, and the grout is injected. An injection layer 54 is formed. At this time, the surplus slime in the cutting and stirring layer 52 on the grout injection layer 54 is discharged to the slime pit 53 through the hole 51 by the pressure of the grout and the air lift effect. In addition, the induced discharge of grout is significantly suppressed, and the amount of grout in excess slime is minimized.

The above-described injection of the high-pressure grout with air gradually expands upward in accordance with the rise in the rotation of the injection rod 1, and when a quick-hard grout is used, as shown in FIG. The grout injection layer 54 partially solidifies from the stage before reaches the planned improvement area upper limit D _U , and the growth of the hard improved body 55 starts. In this way, when finishing the injection of grout to plan improved range upper limit D _U, pumping and grout pumping of compressed air to the injection rod 1 is stopped, injected by the upward movement of the rotary-lifting unit 4 of the construction machine 2 The rod 1 is pulled out of the ground 6, whereby the formation of one improved body 55 in the planned improvement area is completed.

Muddy water (excess slime) discharged into the slime pit 53 during the construction of the jet grouting method
Are continuously processed by the sludge treatment system 60 shown in FIG. That is, the sludge treatment system 60 includes particles (mainly gravel) having a predetermined particle size (about 74 μm) or more from the mud sent from the slime pit 53.
Separating device 61 for separating water, a muddy water tank 62 for storing muddy water (separated muddy water) separated from gravel by the sand separating device 61, and a relay tank installed between the sand separating device 61 and the muddy water tank 62 63.

The sand separator 61 includes a raw water tank 66 for storing mud water sent from a slime pit 53 by a pump (sand pump) 64 through a mud pipe 65, and a mud pipe 65 at an upper portion of the raw water tank 66. And a vibrating sieve 67 for removing coarse substances such as stones and trees from the muddy water, and a muddy water that is installed above the raw water tank 66 and is pumped from the raw water tank 66 by a pump 68 through a pressure pipe 69 to receive the muddy water. And a cyclone 70 for separating sand and gravel from the sand.

Here, the vibrating sieve 67 includes a screen 67a that does not allow coarse substances such as stones and woods to pass through but allows fine particles such as cement and gravel to pass, and a vibrator (not shown) that vibrates the screen 67a. Muddy water sent from the slime pit 53 is well stirred and mixed on the vibrating screen 67a to form a homogeneous liquid mixture in the raw water tank 6.
6 to flow down.

The cyclone 70 has a cylindrical portion 70a and a conical portion 70b.
It is installed in a laterally inclined state such that 0a is slightly above the conical portion 70b. The muddy water pumped from the raw water tank 66 is introduced into the cylindrical portion 70a of the cyclone 70 so as to generate a vortex, and the vortex causes centrifugal force to act on the muddy water. As a result, the gravel having a relatively large particle diameter and a large specific gravity gathers on the inner peripheral wall side of the cyclone 70 and is discharged from the tip opening of the conical portion 70b to the sand discharge pipe 71, while the relatively small particle diameter and Particles of the cement (hardening agent) having a small specific gravity collect together with the liquid at the center of the cyclone 70 and are discharged to the drain pipe 72 from the rear end opening of the cylindrical portion 70a.

Thus, the sand discharge pipe 71 from the cyclone 70
The sand and gravel discharged into the ash is a slurry containing considerable moisture. Therefore, in the present embodiment, the gravel is guided to the dehydrator 73 attached to the raw water tank 66. The dehydrator 73 has a screen 73a at the upper part through which sand and gravel do not pass but through which cement particles pass, and a return water gutter 73b at the lower part which returns muddy water (including cement particles) passing through the screen 73a to the raw water tank 66. As a whole, a box motion is performed by a rocking device (not shown). As a result, the gravel (slurry) discharged from the cyclone 70 onto the screen 73 through the sand discharge pipe 71 gradually moves to the tip side of the screen 73 by the box movement of the dehydrator 73.
Most of the water is removed from the slurry, and freshly-dried gravel appears. The gravel falls, for example, from the screen 73 onto the conveyor 74 and is carried out of the system.

On the other hand, the muddy water containing the cement particles (separated muddy water) discharged from the cyclone 70 to the drainage pipe 72 falls through the screen 75 into the intermediate tank 63. The screen 75 does not allow sand and gravel to pass through, but allows cement particles to pass through. The screen 75 further removes sand and gravel from the separated muddy water, and
In No.3, mud containing almost no gravel will be stored. The muddy water once stored in the relay tank 63 is sent to the muddy water tank 62 by a pump 76 through a mud feeding pipe 77. The muddy water tank 62 has a built-in agitator 78 that is rotationally driven by a driving means (not shown). The rotation of the agitator 78 prevents solidification of the muddy water stored in the muddy water tank 62. In addition,
A switching valve 79 is interposed in the middle of the mud feed pipe 77, and by operating the switch valve 79, the relay tank 63 is connected to the water pipe 8.
0 is selectively connected to a water tank (not shown).

A description will now be given of a sludge treatment method performed by combining the sludge treatment system 60 configured as described above with the jet grouting method (FIGS. 2 to 4). According to the jet grouting method, the injection rod 1 is rotated down, and the planned improvement area upper limit D _{U is} mainly determined by the drill bit 26.
Drilling process to drill the hole 51 up to, and the injection head 23
In the cutting and stirring process in which ultra-high pressure water (mixed fluid) accompanied by air is jetted from the double nozzle 24 to strongly cut and mix the ground to form the cutting and stirring layer 52 up to the lower limit D _{L of the} planned improvement area, Since there is no grout discharge from the head 23,
During these two strokes, the relay tank 63 is connected to a water tank (not shown) by operating the switching valve 79.

In this state, the vibrating sieve 67 is moved from the slime pit 53 to the raw water tank 66 by operating the sand pump 64.
The muddy water in the raw water tank 66 is pumped to the cyclone 70 by operating the cyclone pump 68 when a certain amount of muddy water is accumulated in the raw water tank 66 through the process. As a result, sand and gravel are separated from the muddy water in the cyclone 70, and the separated sand and gravel are sent to the dehydrator 73 through the sand discharge pipe 71, where they are continuously dewatered, and then conveyed out of the system by the conveyor 74. Since the gravel does not contain cement, it can be reused as construction material.

On the other hand, muddy water (separated muddy water) from which gravel has been removed in the cyclone 70 passes through a drain pipe 72 and is transferred to the relay tank 6.
3 at this stage, since it does not contain any grout at this stage, it is almost in a state close to fresh water by separation in the cyclone 70, and the cleanliness can be further increased through the screen 74. Can store extremely clean water. Thereafter, the water in the relay tank 63 is sent to a water tank (not shown) by the operation of the pump 77 and is discharged as it is, or is jetted from another nozzle such as the double nozzle 24 of the injection head 23 for jet water. Will be reused as

In the jet grouting method, after the injection rod 1 is rotated and raised, high pressure grout is injected from the double nozzle 24 and the inclined nozzle 38 of the injection head 23 to form the improved body 55. When the process shifts to the formation process, muddy water containing grout is discharged to the slime pit 53. Therefore, after a lapse of a short time since the shift to the development process, when the treatment of the muddy water previously stored in the raw water tank 66 is almost finished, the operation of the cyclone pump 68 is temporarily stopped, and the raw water tank 66 is stopped. The muddy water discharged in the above-mentioned construction process is stored therein. When an appropriate amount of muddy water is stored in the raw water tank 66, the cyclone pump 68 is operated again to pump the muddy water to the cyclone 70, and at the same time, the switching valve 79 is switched to the muddy water tank 62 side.

As a result, in the cyclone 70, the gravel is separated from the muddy water, and the separated gravel is conveyed to the outside of the system by the conveyer 74 via the dehydrator 73 in the same manner as described above.
On the other hand, the separated muddy water from which the gravel has been removed is sent to the muddy water tank 62 via the relay tank 63 since the switching valve 79 is switched to the muddy water tank 62 side. The mud sent into the mud tank 62 contains a large amount of cement and has the same properties as grout. If left as it is, it will solidify. However, since the agitator 78 is disposed in the muddy water tank 62, solidification of grout (muddy water) is prevented by rotating the agitator 78.

By the way, the grout sent to the mud tank 62 is reduced to 1/3 to 1/2 of the total amount of sludge due to the separation of the gravel in the cyclone 70, and is also formed by the jet grout method. The amount is extremely small because it was generated in a limited manner by the sludge treatment during the process. Therefore, in the present embodiment, the muddy water tank 62
The concentration of the hardening agent (cement) in the muddy water in the inside is measured, the hardening agent concentration is adjusted based on the measurement result, and the grout is regenerated.
(FIG. 4). of course,
It can be used as an injection grout in the jet grout method. In this case, after adjusting the concentration of the curing agent, the grout is returned to the grout mixer 12 in the construction plant 3.

In the above-described embodiment, the switching valve 79 is switched in accordance with the drilling and cutting agitating process and the forming process of the jet grouting method, and the muddy water separated by the cyclone 70 is stored in a water tank (not shown). Although the system is divided into the muddy water tank 62 and the muddy water treatment system 60, two systems of the muddy water treatment system 60 may be provided so as to be selectively used in the drilling and cutting agitating process and the formation process. The jet grouting method to which the present invention is applied is not particularly limited in its method, and can be applied to the above-mentioned general-purpose single-pipe method, double-pipe method, and triple-pipe method.

[0034]

As described above, according to the sludge treatment method for the jet grout method according to the present invention, the gravel is separated and removed from the sludge using a cyclone, and the separated muddy water is subjected to component adjustment. And reuse it as grout,
The troublesome procedure of disposing as industrial waste is not required, and the cost of sludge treatment is greatly reduced. In addition, the sand and gravel separated by the cyclone can be used as construction materials as they are, which is a great advantage in terms of resource saving and energy saving.

[Brief description of the drawings]

FIG. 1 is a system diagram schematically showing a sludge treatment system for a jet grout method according to the present invention.

FIG. 2 is a system diagram schematically showing one system of a jet grout method to which the present sludge treatment method is applied.

FIG. 3 is a sectional view showing a structure of an injection rod used in the system shown in FIG. 2;

FIG. 4 is a cross-sectional view schematically showing an embodiment of a jet grout method according to the system shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection rod 2 Construction machine 3 Construction plant 24 Double nozzle 26 Drilling bit 38 Inclined nozzle 53 Slime pit 55 Improved body 55 60 Sludge treatment system 61 Sand separator 62 Mud tank 63 Relay tank 66 Raw water tank 67 Vibrating sieve 70 Cyclone 73 Dehydrator 78 Agitator

[Procedure amendment]

[Submission date] May 11, 1998

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

[Title of the Invention] Sludge treatment method for high-pressure injection stirring method

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating sludge generated by a high-pressure jet stirring method , which is one of ground improvement methods.

[0002]

[Prior art] Jet grouting method(Jet Gras
Uto is a registered commercial) high-pressure jet stirring method
While rotating or lowering the injection rod into the ground
A grout containing a hardener in the ground through the injection rod.
Injection rods are injected by high pressure to create an improved body.
Where a large-diameter improved body can be created just by making one round trip
Therefore, it is frequently used for ground improvement in recent years.

[0003] As a high-pressure injection stirring method , a single pipe method in which only a grout is injected at a high pressure using a single pipe rod by selecting an injection rod (see Japanese Patent Publication No. 48-25768, etc.), and a double pipe rod are used. Using a double pipe method of mixing and injecting grout and air (see Japanese Patent Publication No. 56-44206, etc.), and cutting and stirring the ground by injecting air and water at high pressure using a triple pipe rod. A triple pipe method in which grout is injected at high pressure into the stirring layer (Japanese Patent Publication No. 58-27364)
And the like, and any one of them is adopted according to the properties of the improved ground, the scale of the improvement, and the like.

[0004]

[Problems to be solved by the invention] By the way, this kind of
In the high-pressure injection agitation method , the ground is cut and stirred over a wide area by the high-pressure injection of grout (and air or water), and a large amount of excess slime (muddy water) is generated, and this muddy water is discharged to the ground through the periphery of the injection rod. Become so. Therefore, when implementing the high-pressure injection stirring method ,
An important issue is how to treat the mud (discharged) discharged to the ground. However, as described above, the amount is large, so even if it is stored in a nearby tank, etc., it will be full sooner. Becomes Therefore, conventionally, pitch transported by a vacuum truck and dumped as industrial waste in an appropriate sedimentation basin, but it is quite difficult to secure the sedimentation basin described above due to recent land conditions, environmental conditions, etc. However, there is a problem that the transportation distance by the vacuum vehicle is further increased, and that the above-mentioned sludge treatment requires a large cost.

[0005] In some cases, the muddy water is subjected to a filter press to be dewatered and then discarded. However, since a large amount of a hardening agent composed of fine particles is present in the muddy water, a filter is not used. It was clogged at an early stage, and in fact, its use had to be abandoned.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a high-pressure injection stirring
It is an object of the present invention to separate sand and gravel from muddy water generated by the construction method and to reuse the sand and gravel, thereby significantly reducing the cost required for sludge treatment.

[0007]

Means for Solving the Problems In order to solve the above problems, the present invention sends muddy water generated by a high-pressure jet stirring method to a raw water tank through a screen, and during construction of the improved body, passes around an injection rod to the ground. The discharged muddy water is sent to the raw water tank through a vibrating sieve, and further, the muddy water in the raw water tank is sent at high speed into a cyclone, and the gravel is separated from the muddy water using centrifugal force, and then separated by the cyclone. The method is characterized in that the concentration of the hardening agent in the muddy water is measured, the concentration of the hardening agent is adjusted based on the measurement result, and thereafter, this is reused as grout.

In such a sludge treatment method, muddy water having a high hardener concentration is obtained by separating and removing a large amount of sand and gravel occupying a high proportion of the sludge by a cyclone, and the hardener concentration in the muddy water is obtained. Can be reused as grout by measuring the concentration and adjusting the concentration appropriately.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 2 to FIG. 4 show one embodiment of a high-pressure jet stirring method to which the present invention is applied. This high-pressure injection stirring method includes an injection rod 1 having a double pipe structure, which will be described in detail later, a self-propelled construction machine 2 and a construction plant 3. The construction machine 2 includes a leader 5 equipped with a rotating / elevating unit 4 that supports the injection rod 1, and the leader 5 stands upright on the ground 6 during construction. The injection rod 1 is detachably supported by a rotating / elevating unit 4 that moves up and down along the vertically erected reader 5, and rotates or descends according to its operation. A double pipe swivel 7 is attached to the upper end of the injection rod 1, and a high pressure pump 8 and an air compressor 9 in the construction plant 3 are connected to the double pipe swivel 7 by piping.

In the construction plant 3, in addition to the high-pressure pump 8 and the air compressor 9, a water tank 10, a cement silo 11, a grout mixer 12, and the like are installed. The grout mixer 12 has a function of stirring and mixing the cement (hardening agent) taken in from the cement silo 11 and the water taken in from the water tank 10 to produce grout (cement milk). The admixture is supplied from the admixture tank 13.
The water tank 10 and the grout mixer 12 are connected to the high-pressure pump 8 via a switching valve 14 by piping.
By operating the switching valve 14, water or grout is selectively supplied to the high-pressure pump 8. The high-pressure pump 8
From high-pressure water of about 0 to 20 MPa (about 100 to 200 kgf / cm ² ), 35 to 45 MPa (about 350 to 450 MPa)
kgf / cm ² ), and has a function of producing a high-pressure grout of about 35 to 45 MPa in addition to a function of producing a high-pressure grout of about 35 to 45 MPa. Either one is selectively supplied. In addition, 15 is a generator as a power source of the construction plant 3.

As shown in FIG. 3, the injection rod 1 has a rod body 22 having a double pipe structure having an outer pipe 20 and an inner pipe 21, and an injection head 23 connected to the rod body 22. It is schematically composed of The high pressure pump 8 in the construction plant 3 is connected to the first flow path a in the inner pipe 21 constituting the rod body 22 through the double pipe swivel 7, while the outer pipe 20 and the inner pipe are connected. 21 is also provided with a double pipe swivel 7.
The air compressor 9 in the construction plant 3 is connected via a pipe.

The injection head 23 is roughly composed of an upper head portion 25 provided with a plurality of double nozzles 24 on the side surface and a lower head portion 27 provided with a drill bit 26 at the tip. The upper head portion 25 has a double tube structure including an outer cylinder 28 and an inner cylinder 29, and an annular passage c is formed between the outer cylinder 28 and the inner cylinder 29. The lower portions of the outer cylinder 28 and the inner cylinder 29 are closely fitted to each other, and the bottom of the annular passage c is closed at the fitting portion. A first nozzle unit 30 forming the double nozzle 24 is screwed and fixed to the outer cylinder 28, and a second nozzle unit 31 similarly forming the double nozzle 24 is screwed to the inner tube 29. . The second nozzle unit 31 is extended across the annular passage c, and its tip is inserted into the first nozzle unit 30. A gap of a predetermined size is secured between the first nozzle unit 30 and the second nozzle unit 31, and therefore, the double nozzle 24 is provided at the center thereof with the injection leading to the passage d in the inner cylinder 29. The hole has a structure in which an injection hole around the annular passage c is independently provided.

The upper head portion 25 is connected to the rod body 22 by screwing the outer cylinder 28 to the outer tube 20 of the rod body 22, and in this connection state, the inner cylinder 29
The inner pipe 21 of the rod body 22 is provided with a sealing member 32
To fit in a liquid-tight manner. Therefore, the first flow path a in the rod body 22 passes through the passage d in the inner cylinder 29 to the injection hole on the core side of the double nozzle 24, and the second flow path b in the rod body 22 Through the annular passage c, it communicates with the injection holes outside the double nozzle 24 respectively.

The upper head portion 25 also has its outer cylinder 28
Is screwed into the main body 33 of the lower head portion 27 to be connected to the lower head portion 27. In this connected state, the inner cylinder 29 is connected to the upper end of the main body 33 of the lower head portion 27 via a sealing member 34. It is to be closely matched.
The main body 33 of the lower head portion 27 has a communication passage e therein communicating with a passage d in the upper head portion 25,
The lower end has a tapered screw hole 33a into which the tapered shank 35 of the drill bit 26 is screwed.

The drill bit 26 is provided with a plurality (three in this case) of cutting edges 37 equally spaced in the circumferential direction on a main body portion 36 on the distal end side thereof, and one inclined edge inside the cutting edge 37. A nozzle 38 is provided. The inclined nozzle 38 is attached to an inclined hole 39 formed in the main body 36 such that the axis thereof intersects the axis of the injection rod 1 at a predetermined angle θ. Shank 35 and body 36 of drill bit 26
Inside the communication passage e in the main body 33 of the lower head portion 27
Is formed in a series of communication holes 40 which communicate with the inclined hole 39. Therefore, the pressurized fluid is formed in the inclined nozzle 38 through the first flow path a in the nozzle body 22 and the passage d in the injection head 23. (Water or grout). Thus, the diameter of the inclined nozzle 38 is set so as to have substantially the same flow passage area as the injection hole on the core side of the double nozzle 24. Thereby, the injection head 2 is now passed through the first flow path a of the nozzle body 22.
When the pressurized fluid is pressure-fed to the passage d in 3, the pressurized fluid is commonly ejected from the double nozzle 24 and the inclined nozzle 38. The inclination angle θ of the inclined nozzle 38 is set to an appropriate value according to the diameter of the drill bit 26 and the pressure of the high-pressure water.

At the time of construction, the injection rod 1 composed of the rod body 22 and the injection head 23 is supported by the rotating / elevating unit 4 of the construction machine 2 in the mode shown in FIG. The high pressure pump 8 and the air compressor 9 in the construction plant 3 are connected to the double pipe swivel 7 at the upper end. After completion of the preparation, the set pressure of the high-pressure pump 8 is adjusted, high-pressure water (about 10 to 20 MPa) is supplied to the first flow path a in the injection rod 5, and the high-pressure water is supplied to the side of the injection head 23. The rotating / elevating unit 4 is operated while ejecting the injection nozzle 1 from the double nozzle 24 and the inclined nozzle 38 at the tip of the double nozzle 24 to rotate the injection rod 1 down into the ground 6. Thus, the ground 6 is cut by the high-pressure water jetted from the double nozzle 24 and the inclined nozzle 38, and at the same time, is mechanically cut by the drill bit 26. Drilling can be performed quickly and efficiently. Further, since the drill bit 26 is cooled by water, its wear is suppressed. In addition, the high-pressure water spouted from the inclined nozzle 38 diffuses in front of the drill bit 26 in accordance with the rotation of the injection rod 1 and preliminarily cuts the front area thereof. The soil is crushed in advance, and problems such as adhesion of the viscous soil to the drill bit 26 and hindering its cutting ability are also solved.

In this way, a hole 51 having a diameter slightly larger than the diameter of the drill bit 26 is formed in the ground 6 as shown in FIG.
_When the pressure reaches _U, the set pressure of the high-pressure pump 8 is adjusted, and the high-pressure water to be pumped to the first flow path a in the injection rod 1 is switched to ultra-high-pressure water (about 35 to 45 MPa). A high pressure (686 to 980 kPa ... 7 to 10 kgf / c) is supplied from the air compressor 9 to the second flow path b in the injection rod 1.
m ² ) of compressed air. Ultra-high-pressure water (mixed fluid) accompanied by air is jetted from the double nozzle 24 of the injection head 23 by pressure-feeding of the ultra-high-pressure water to the first flow path a. The inside is strongly cut and stirred. As a result, a large-diameter cutting and stirring layer 52 is formed in the ground 6, and the cutting and stirring layer 52 gradually expands downward as the injection rod 1 rotates downward. The surplus slime (muddy water) generated at this time is discharged to a slime pit 53 on the ground through a hole 51 formed in the drilling process, and is further sent to a sludge treatment system described later.

[0019] Then, formation of the cutting stirred layer 52 by cutting agitation described above, namely When cutting agitation stroke reaches planning improved range lower limit D _L, construction plant 3 in the switching valve 14
Is switched to the grout mixer 12 side, and high-pressure (about 35 to 45 MPa) grout is pressure-fed to the first flow path a in the injection rod 1, and compressed air is supplied to the second flow path b in the injection rod 1. The injection rod 1 is rotated up while continuing the pressure feeding. Thereby, high-pressure grout (mixed fluid) accompanied by air is injected from the double nozzle 24 of the injection head 23, and high-pressure grout is jetted from the inclined nozzle 38, and the grout is injected into the cutting and stirring layer 52, and the grout is injected. Injection layer 54
Is formed. At this time, the surplus slime in the cutting and stirring layer 52 on the grout injection layer 54 is discharged to the slime pit 53 through the hole 51 by the pressure of the grout and the air lift effect. In addition, the induced discharge of grout is significantly suppressed, and the amount of grout in excess slime is minimized.

The above-described injection of the high-pressure grout accompanied by air gradually expands upward in accordance with the rotation rise of the injection rod 1, and when a quick-hard grout is used, as shown in FIG. There is grouted layer 54 from the previous step reaching plan improved range upper limit D _U partially solidified,
The growth of the hard improvement 55 begins. In this way, when finishing the injection of grout to plan improved range upper limit D _U, pumping and grout pumping of compressed air to the injection rod 1 is stopped, injected by the upward movement of the rotary-lifting unit 4 of the construction machine 2 The rod 1 is pulled out of the ground 6, whereby the formation of one improved body 55 in the planned improvement area is completed.

The muddy water (excess slime) discharged to the slime pit 53 during the construction of the high-pressure jet stirring method
Are continuously processed by the sludge treatment system 60 shown in FIG. That is, the sludge treatment system 60 includes a sand separator 61 that separates particles (mainly gravel) having a predetermined particle size (about 74 μm) or more from the mud sent from the slime pit 53. A muddy water tank 62 for storing muddy water (separated muddy water) separated from sand and gravel, and a relay tank 63 installed between the sand separating device 61 and the muddy water tank 62.

The sand separation device 61 includes a slime pit 53
A raw water tank 66 for storing the muddy water sent through a mud pipe 65 by a pump (sand pump) 64 from above, and receives muddy water from the muddy pipe 65 at the upper part of the raw water tank 66, and coarsens stones, trees, etc. from the muddy water. A vibrating sieve 67 for removing objects and a cyclone 70 installed above the raw water tank 66 for receiving muddy water pumped from the raw water tank 66 by the pump 68 through the pumping pipe 69 and separating sand and gravel from the muddy water. .

Here, the vibrating sieve 67 includes a screen 67a that does not allow coarse substances such as stones and wood to pass through but allows fine particles such as cement and gravel to pass, and a vibrator (not shown) that vibrates the screen 67a. Equipped with slime pit 53
Is well stirred and mixed on the vibrating screen 67a, and flows down into the raw water tank 66 as a homogeneous mixed solution.

The cyclone 70 includes a cylindrical portion 70a and a conical portion 70b. Here, the cyclone 70 is installed in a laterally inclined state so that the cylindrical portion 70a has a slightly higher orientation than the conical portion 70b. The muddy water pumped from the raw water tank 66 is introduced into the cylindrical portion 70a of the cyclone 70 so as to generate a vortex, and the vortex causes centrifugal force to act on the muddy water. As a result, the gravel having a relatively large particle diameter and a large specific gravity gathers on the inner peripheral wall side of the cyclone 70, and is discharged from the tip opening of the conical portion 70b to the sand discharge pipe 71.
On the other hand, the cement (hardening agent) particles having a relatively small particle diameter and a small specific gravity are discharged together with the liquid into the cyclone 70.
And is discharged to the drainage pipe 72 from the rear end opening of the cylindrical portion 70a.

The sand discharge pipe 7 from the cyclone 70
The gravel discharged to 1 is in a slurry state containing a considerable amount of water. Therefore, in the present embodiment, the gravel is guided to the dehydrator 73 attached to the raw water tank 66. The dehydrator 73 has a screen 73a at the top through which sand and gravel do not pass but through which cement particles pass,
A return gutter 73b for returning muddy water (including cement particles) passing through the screen 73a to the raw water tank 66 is provided at a lower portion, and the whole of the gutter performs box motion by a rocking device (not shown). ing. As a result, the gravel (slurry) discharged from the cyclone 70 onto the screen 73 via the sand discharge pipe 71 gradually moves toward the tip of the screen 73 by the box movement of the dehydrator 73, and during this time, most of the water from the slurry is removed. Is removed, and freshly-dried gravel appears, and the gravel falls, for example, from the screen 73 onto the conveyor 74 and is carried out of the system.

On the other hand, muddy water containing cement particles (separated muddy water) discharged from the cyclone 70 to the drain pipe 72 is
It falls into the intermediate tank 63 through the screen 75.
The screen 75 does not allow sand and gravel to pass through, but cement particles do.The screen 75 further removes sand and gravel from the separated mud, and the relay tank 63 contains mud containing almost no sand and gravel. It will be stored. The muddy water once stored in the relay tank 63 is sent to the muddy water tank 62 by a pump 76 through a mud feeding pipe 77. The muddy water tank 62 has a built-in agitator 78 that is rotationally driven by a driving means (not shown). The rotation of the agitator 78 prevents solidification of the muddy water stored in the muddy water tank 62. A switching valve 79 is interposed in the middle of the mud pipe 77, and the relay tank 63 is selectively connected to a water tank (not shown) via the water pipe 80 by operating the switching valve 79. It has become so.

Hereinafter, a description will be given of a sludge treatment method performed by combining the sludge treatment system 60 configured as described above with the high-pressure jet stirring method (FIGS. 2 to 4). The high-pressure injection
According to 拌工method, the injection rod 1 is rotated downward, the holes 5 mainly to plan improved range upper limit D _U by drilling bits 26
1 and a super high pressure water (mixed fluid) accompanied by air is jetted from the double nozzle 24 of the injection head 23 to strongly cut and agitate the ground to lower the planned improvement area lower limit _DL.
Since the grout is not discharged from the injection head 23 during the cutting and stirring process in which the cutting and stirring layer 52 is formed up to this point, the operation of the switching valve 79 causes the relay tank 63 to move the water (not shown) during both of these processes. Connect to tank.

In this state, the vibrating sieve 6 is moved from the slime pit 53 to the raw water tank 66 by operating the sand pump 64.
7, the muddy water in the raw water tank 66 is pumped to the cyclone 70 by operating the cyclone pump 68 when a certain amount of muddy water has accumulated in the raw water tank 66. As a result, sand and gravel are separated from the muddy water in the cyclone 70, and the separated sand and gravel are sent to the dehydrator 73 through the sand discharge pipe 71, where they are continuously dewatered, and then conveyed out of the system by the conveyor 74. Since the gravel does not contain cement, it can be reused as construction material.

On the other hand, the mud (separated mud) from which the gravel has been removed in the cyclone 70 is sent to the relay tank 63 via the drain pipe 72, but at this stage, since it contains no grout, the inside of the cyclone 70 The separation tank 63 is almost in a state close to fresh water, and the cleanliness can be further increased through the screen 74. Therefore, extremely clean water is stored in the relay tank 63. Thereafter, the water in the relay tank 63 is sent to a water tank (not shown) by the operation of the pump 77 and is discharged as it is, or is jetted from another nozzle such as the double nozzle 24 of the injection head 23 for jet water. Will be reused as

In the high-pressure injection stirring method , the injection head 2 is thereafter rotated while the injection rod 1 is rotated upward.
The high-pressure grout is injected from the double nozzle 24 and the inclined nozzle 38 to form the improved body 55. When the process proceeds to the formation process, muddy water containing grout is discharged to the slime pit 53. Therefore, after a lapse of a short time since the shift to the development process, when the treatment of the muddy water previously stored in the raw water tank 66 is almost finished, the operation of the cyclone pump 68 is temporarily stopped, and the raw water tank 66 is stopped. The muddy water discharged in the above-mentioned construction process is stored therein. When an appropriate amount of muddy water is stored in the raw water tank 66, the cyclone pump 68 is operated again to pump the muddy water to the cyclone 70, and at the same time, the switching valve 79 is switched to the muddy water tank 62 side.

As a result, the gravel is separated from the mud in the cyclone 70, and the separated gravel is conveyed to the outside of the system by the conveyer 74 via the dewatering machine 73, while the separated mud is removed. Is the switching valve 79
Is switched to the muddy water tank 62 side, and is sent to the muddy water tank 62 via the relay tank 63. The mud sent into the mud tank 62 contains a large amount of cement and has the same properties as grout. If left as it is, it will solidify. However, mud tank 6
Since the agitator 78 is disposed in the inside 2, the agitator 78 is rotated to grout (muddy water).
Is prevented from solidifying.

By the way, the grout sent to the muddy water tank 62 is reduced to 1/3 to 1/2 of the total amount of mud by the separation of gravel in the cyclone 70,
The amount is very small because it is generated in a limited manner by the sludge treatment during the formation process in the high-pressure injection stirring method . Therefore, in the present embodiment, the muddy water tank 6
The hardener (cement) concentration in the muddy water in 2 is measured, the hardener concentration is adjusted based on the measurement result, and the grout is regenerated.
(FIG. 4). of course,
It can also be used as an injection grout in the high-pressure injection stirring method . In this case, after adjusting the concentration of the curing agent, the composition is returned to the grout mixer 12 in the construction plant 3.

In the above embodiment, the high pressure
The muddy water separated by the cyclone 70 is divided into a water tank (not shown) and a muddy water tank 62 by switching the switching valve 79 in accordance with the drilling and cutting agitating process of the injection stirring method and the forming process. It is also possible to provide two systems of the sludge treatment system 60 and selectively use the drilling and cutting agitating process and the forming process. It is also an object of the present invention.
The high-pressure injection stirring method is not particularly the same method, the above-mentioned general-purpose single-tube method, double-tube method, triple-tube method high pressure
Applicable to the injection stirring method .

[0034]

As described above, according to the present invention,
According to the sludge treatment method for the high-pressure jet agitation method , sand and gravel are separated and removed from the sludge using a cyclone, and the separated muddy water is adjusted as a component and reused as grout, so that it is treated as industrial waste. There is no need for complicated procedures, and the cost of sludge treatment is greatly reduced. In addition, the sand and gravel separated by the cyclone can be used as construction materials as they are, which is a great advantage in terms of resource saving and energy saving.

[Brief description of the drawings]

FIG. 1 is a system diagram schematically showing a sludge treatment system for a high-pressure injection stirring method according to the present invention.

FIG. 2 is a high-pressure jet stirring target to be subjected to the present sludge treatment method.
It is a systematic diagram which shows one system of the stirring method schematically.

FIG. 3 is a sectional view showing a structure of an injection rod used in the system shown in FIG. 2;

[4] high-pressure injection stirring Engineering by the system shown in FIG. 2
It is sectional drawing which shows embodiment of a method typically .

[Explanation of Signs] 1 injection rod 2 construction machine 3 construction plant 24 double nozzle 26 drill bit 38 inclined nozzle 53 slime pit 55 improved body 60 sludge treatment system 61 sand separator 62 muddy water tank 63 relay tank 66 raw water tank 67 Vibrating sieve 70 Cyclone 73 Dehydrator 78 Agitator

Claims (1)

[Claims] 1. A jet grouting method in which a grout containing a hardening agent is injected at a high pressure into the ground through the injection rod while rotating or lowering the injection rod into the ground to form an improved body. The mud discharged to the ground is sent to the raw water tank through a vibrating sieve,
Furthermore, the muddy water in the raw water tank is sent into the cyclone at a high speed, and the gravel is separated from the muddy water using centrifugal force.Then, the concentration of the hardener in the muddy water separated by the cyclone is measured. Adjust the curing agent concentration based on the measurement results,
Thereafter, this is reused as grout, which is a method for treating sludge in a jet grout method.