JPH07259467A - Excavated mud treating method - Google Patents

Abstract

PURPOSE:To reduce an operating load of a vacuum car by way of reducing the amount mud by supplying the sludge water emerged during or after excavating to a liquid cyclone, concentrating the sludge water and carrying out the concentrated sludge water by the vacuum car. CONSTITUTION:Mud in a hole 2 containing sediment excavated by an excavator 1 is treated by a sediment separation device 3, coarse grains are separated, the mud is put in a precipitator 6, and returned into the hole 2 and circulated. In the meantime, in the case when the specific gravity of the drilling mud in the precipitator 6 exceeds a specific gravity range suitable for a continuous underground wall, the drilling mud in the precipitator 6 is supplied to a liquid cyclone 11 as sludge water, and new drilling mud is properly put in the precipitator 6 or the hole 2. Thereafter, the drilling mud concentrated in the liquid cyclone 11 is taken out as cyclone under and put in a concentrating tank 21. Dimension of each part of the liquid cyclone is adjusted so that the specific gravity of the supplied drilling mud becomes moderate. Thereafter, the concentrated drilling mud in the concentrating tank 21 is delivered to a vacuum car as a carrier means by a pump 22, and it is taken out to a specified intermediate disposal plant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste mud treatment method for treating waste mud produced by a mud construction method, and more particularly to a waste mud treatment method for carrying out waste mud by a vacuum truck.

[0002]

2. Description of the Related Art In the so-called mud construction method of excavating the ground while circulating mud, the specific gravity of the mud in the excavation hole is maintained at about 1.05 to 1.1 in the case of the continuous underground wall construction method during excavation to improve the excavation efficiency. It is necessary to avoid deterioration and deterioration of the replaceability in concrete pouring.

Therefore, for muddy water having a large specific gravity, it is drawn out from a sand settling tank, etc., fine particles are separated and removed by a screw decanter, and then returned to a hole for reuse, or reused at a small excavation site. It is treated as waste mud without using it, and new mud is added instead.

Further, after excavation, those that can be diverted to another excavation are diverted, and those that cannot be diverted due to their large specific gravity are also treated as waste mud.

In a large site, such waste mud is dehydrated by a roll press, a filter press or the like before being carried out, but if the excavation scale is small and there is no such treatment facility, it is suctioned out by a vacuum car. Often, dehydration treatment is carried out at the intermediate treatment plant at the destination.

FIG. 3 shows a procedure of waste mud water treatment when a vacuum truck is used, including an excavation step and a sediment separation step.

As shown in the figure, first, the earth and sand excavated by the excavator 1 is sucked up together with the mud from the hole 2, and then the earth and sand is put into the earth and sand separating device 3 installed on the ground.

Then, the vibrating screen 4 provided in the earth and sand separating device 3 removes a predetermined coarse particle content from the muddy water.

Next, the muddy water from which coarse particles have been removed is taken out from the liquid cyclone 5 provided in the earth and sand separating device 3 as over muddy water, once placed in the sand settling tank 6, and then the hole 2 is again opened.
Put it back in and circulate.

On the other hand, the muddy water in the sand settling tank 6 in which the fine particles are increased and the specific gravity is increased is periodically sucked in and carried out by the vacuum truck 8, and new muddy water is added to the hole 2 or the sand settling tank 6 in place of the muddy water. It prevents the specific gravity of muddy water from increasing.

After the end of excavation, the muddy water in the hole 2 having a large specific gravity is once put in the recovery tank 10 and then carried out by the vacuum vehicle 8 as waste muddy water.

[0012]

However, when the amount of waste muddy water increases, not only the amount of muddy water to be added increases but also the number of vacuum vehicles to be operated increases and the vacuum vehicles frequently come to the site. There was a problem that it came in and went out and delayed other processes, adversely affecting the whole construction period, and further raising the construction cost.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a waste mud treatment method capable of reducing the amount of waste mud to reduce the operating load of a vacuum vehicle.

[0014]

In order to achieve the above object, the waste mud treatment method of the present invention, as set forth in claim 1, supplies waste mud to a liquid cyclone type centrifugal separation means. And a carrying-out step of carrying out the concentrated waste mud water by a predetermined carrying means.

[0015]

In the waste mud treatment method of the present invention, first, the waste mud having a large specific gravity is supplied to the liquid cyclone type centrifugal separating means to concentrate the waste mud. Then, the concentrated waste mud water is carried out by a transportation means such as a vacuum truck.

Thus, if the waste mud is concentrated in advance, the weight of the solid content contained in the waste mud per unit volume increases, and as a result, the total amount of the waste mud to be treated decreases.

[0017]

EXAMPLES Examples of the waste mud treatment method of the present invention will be described below with reference to the accompanying drawings. It should be noted that parts and the like which are substantially the same as those of the conventional technique are designated by the same reference numerals and the description thereof will be omitted.

FIG. 1 shows the procedure of the waste mud treatment method of this embodiment, including the preceding steps, that is, the excavating step, the sediment separating step and the concrete placing step.

In the excavation process and the sediment separation process,
The muddy water in the hole 2 containing the earth and sand excavated by the excavator 1 is treated by the earth and sand separator 3 to separate coarse particles, and then the muddy water from which the coarse particles have been removed is once put into the sand settling tank 6. The muddy water is returned to the hole 2 and circulated.

On the other hand, the specific gravity of the muddy water in the sand settling tank 6 exceeds the specific gravity range 1.05 to 1.1 suitable for the continuous underground wall, for example, 1.2.
When it becomes, the muddy water in the sand settling tank 6 is supplied as waste muddy water to the liquid cyclone 11, which is a liquid cyclone type centrifugal separating means, and new muddy water is appropriately put in the sand settling tank 6 or the hole 2.

Next, the muddy water concentrated by the liquid cyclone 11 is taken out as a cyclone under, and this is put into the concentration tank 21.

The dimensions of each part of the liquid cyclone 11 are adjusted so that the specific gravity of the supplied muddy water is concentrated to about 1.3, for example.

FIG. 2 is a sectional view showing the hydrocyclone 11.

Here, in the conventional hydrocyclone 5, the ratio Du / Do of the overflow finder diameter Do and the underflow nozzle diameter Du was designed to be in the range of about 0.5 to 0.6. Then Du / Do
Is set to 0.2 to 0.4, preferably 0.25 to 0.35, and more preferably approximately 0.3, so that fine particles such as silt can be taken out as under mud.

Then, the concentrated mud in the concentration tank 21 is pumped by the pump 2.
In step 2, it is sent to a vacuum vehicle as a transportation means and is carried out to a predetermined intermediate treatment plant.

On the other hand, the muddy water from which fine particles have been removed and which has a specific gravity of 1.05 to 1.1 suitable for excavation is taken out as overmuddy water of the liquid cyclone 11 and returned to the hole 2 or the sand settling tank 6 to be reused as muddy water in the drilling hole. use.

When pouring concrete after the completion of excavation, the muddy water in the hole 2 having a large specific gravity is once put in the recovery tank 10 to allow coarse particles to settle in advance. Next, the muddy water in the recovery tank 10 containing the fine particles is supplied to the liquid cyclone 11 as waste muddy water.

Similar to the procedure during the excavation, the muddy water concentrated in the liquid cyclone 11 is taken out as a cyclone under into the thickening tank 21, and the concentrated muddy water is sent to the vacuum car 8 by the pump 22 to a predetermined intermediate treatment plant. To carry out.

As described above, according to the waste mud treatment method of this embodiment, the waste mud generated during or after the excavation is once concentrated and then carried out by the vacuum vehicle. The proportion of solids contained in the waste mud water increases, and as a result, the total amount of waste mud water to be treated decreases.

That is, for example, waste muddy water having a specific gravity of 1.2 is
Considering the case where the product is concentrated to 1.3 and then carried out by a vacuum truck, the weight of fine particles contained in a unit volume of waste mud water is 1.
5 times increase. On the other hand, the amount of fine particles is constant if the drilling capacity is the same, so the volume of waste mud water to be treated is reduced to 2/3 compared to the case without concentration, and the reduction amount is 33%. .

Therefore, the number of operating vacuum vehicles can be significantly reduced, and the possibility that the vacuum vehicles frequently enter and leave the site and delay other processes is reduced.

Since the amount of waste mud water decreases, the amount of mud water that can be returned to the drill hole and reused increases.
The amount of muddy water that must be newly created can be reduced.

In this embodiment, the waste mud water is first concentrated and then put into the concentration tank, but it may be directly put into the vacuum truck.

Further, in this embodiment, since it was premised that waste mud produced by the underground continuous wall method was treated, the specific gravity of mud before condensation was set to 1.05 to 1.1. The specific gravity of the muddy water is not limited to such a range, for example, 1.00 to 1.10 in the reverse construction method, 1.10 to 1.25 in the muddy water shield construction method, and may be appropriately set depending on the purpose of use and the type of muddy water. .

Further, in the present embodiment, the target value of concentration is set as
However, it goes without saying that the degree of concentration may be increased.

[0036]

As described above, the waste mud treatment method of the present invention comprises a concentrating step of concentrating the waste mud by supplying the waste mud to a liquid cyclone type centrifugal separating means, and the concentrated waste mud. And a carrying-out step of carrying out the product by a predetermined carrying means, it is possible to reduce the amount of waste mud water and reduce the working load of the vacuum vehicle.

[0037]

[Brief description of drawings]

FIG. 1 is a schematic view showing a procedure of a waste mud treatment method according to this embodiment.

FIG. 2A is a vertical cross-sectional view of a liquid cyclone used in the waste mud treatment method of this embodiment, and FIG. 2B is a horizontal cross-sectional view taken along the line AA of FIG.

FIG. 3 is a schematic diagram showing a procedure of a conventional waste mud treatment method.

[Explanation of symbols]

1 Excavator 2 Drilling Hole 3 Sediment Separation Device 6 Sand Settler 8 Vacuum Vehicle (Transportation) 10 Recovery Tank 11 Liquid Cyclone (Cyclone Type Centrifugal Separation Means) 21 Concentration Tank 22 Pump

Claims (1)

[Claims] 1. A concentration step of supplying the waste mud water to a liquid cyclone type centrifugal separation means to concentrate the waste mud water, and a carrying-out step of carrying out the concentrated waste mud water by a predetermined transportation means. Characteristic waste mud treatment method.