JPH01178695A - Muddy water recovery system - Google Patents

Abstract

PURPOSE:To permit the upper part of a sand settling tank to be used all the time without causing troubles in continuous operations by a method in which highly viscous muddy water using in muddy-water excavation work is sent to a slime settling tank and slime is deposited and removed from the lower discharge port. CONSTITUTION:Highly viscous muddy water used in muddy-water excavation work is sucked up through a tube 11 from excavated pit 1 and mixed with a dilutant stored in a tank 14 in a line mixer 20. The mixture is sent into a slime settling tank 6 where slime of comparatively great specific gravity is deposited on the bottom and muddy water deprived of slime is sent from a port 22 into a storage tank 8. The slime so deposited is removed from the lower port 30. The muddy water regenerated is circulated through a pipe 10 from the tank 8 to the pit 1 for reuse.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a recovery system for high viscosity mud water in a mud excavation method, and particularly to a mud water recovery system characterized by its slime removal means.

(Prior Art) As is well known, in construction work in the field of urban civil engineering, underground walls, peripheral walls of tanks, foundation piles, etc. are constructed using muddy water excavation methods.

This construction method mainly consists of suspending clay such as bentonite in water, adding dispersants and thickeners to create muddy water, and filling the ground while excavating a trench or circular section.
After excavating to a predetermined depth, the muddy water inside is replaced with concrete, and the concrete is hardened to construct walls and piles underground.

In this type of construction method, if the excavated ground is permeable, such as gravel ground, muddy water excessively seeps into the surrounding ground and flows out, making it difficult to constantly fill the excavation hole with muddy water.

Therefore, in place of the muddy water containing bentonite as its main component, the applicant used a vegetable viscous substance dissolved in water, borax,
We proposed a muddy solution containing additives such as boric acid. In this type of mud drilling method, the mud used for excavation, including the highly viscous mud, is reused, and when reusing it, it is necessary to separate the mixed earth and sand.

For separation, the muddy water filling the excavation hole is pumped up and stored in a collection tank, and separated based on the difference in specific gravity between the muddy water and the muddy water.

That is, the recovery tank has a sand settling tank, and at the stage before the mud storage liquid tank, the flow rate of the collected mud is made to flow slowly in the tank.
Slime in muddy water is allowed to settle and accumulate.

(Problem to be Solved by the Invention) However, the work of removing the slime deposited at the bottom of the sand settling tank using a vacuum hose, hydraulic climb shell, etc. is difficult when the sand settling tank is used with a reinforcing frame placed above it. This could not be done if muddy water was being recirculated.

These operations require a long removal time, depending on the capacity of the vacuum truck and climb shell and the amount of slime deposited.
There were also problems with continuous work such as the next excavation process.

The present invention has been made in view of the above circumstances, and its purpose is to provide a muddy water recovery system that can remove slime from the sand settling tank while keeping the upper part of the tank available at all times, and can also remove slime even during muddy water circulation. is to provide.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a collection system constituting a recovery and reprocessing system for high viscosity mud water used in a mud construction method, in which high viscosity mud water is sucked up from an excavation hole. A slime settling tank that receives the protrusion of the mud pumping pipe and is equipped with a mud water transport port, and a mud storage tank that receives mud water from the transport port and mud water from a mixing line, etc. to which necessary ingredients and water are added as necessary. It is characterized by comprising a tank, a mud water supply line that supplies the high viscosity mud water from the mud storage tank into the borehole, and a slime removal port that can be opened and closed at the bottom of the slime settling tank. .

(Function) According to the muddy water collection system having the above configuration, the slime in the slime settling tank, which has a relatively specific gravity, settles and accumulates at the bottom of the tank, and the muddy water from which the slime has settled is transported to the muddy water. Mud water is sent from the mouth to the mud storage tank, and from the mud storage tank, mud is supplied into the borehole as needed. Separately from these flows, the slime deposited on the bottom of the slime settling tank is removed by arbitrarily opening the slime removal port at the bottom.

(Example) Hereinafter, an example of the present invention will be described in detail using the drawings.

The figure is an explanatory diagram showing a high viscosity muddy water supply/recovery system to which the present invention is applied. In the figure, 1 is an excavation hole, 2 is a muddy water supply line for the excavation hole, and 3 is a recovery line for recovering the muddy water in the excavation hole 1. The muddy water recovery system comprises a supply line 2 and a recovery line 3.

The supply system 2 includes a mixer 4 that mixes viscous substances, water, and preservatives, and a mud storage tank 8 that stores the mud mixed and stirred by the mixer 4 and the mud collected from the sand settling tank 6.
and a muddy water supply pipe 10 connected to the muddy water outlet side of the liquid tank 8.

The discharge end of this muddy water supply pipe 10 is arranged inside the excavation hole 1. On the other hand, the recovery line 3 is a slurry lifting pipe connected to a submersible pump placed in the excavation hole 1, and a feed pipe 16 for joining the recovery pipe 12 from 11 with the viscosity reducing agent stored in the storage tank 14. A line mixer 20 is provided in the same way as above on the mixing line 18 that merges the two, and the terminal end of the mixing line 18 is connected to the sand settling tank 6 at the discharge end side of the line mixer 20.

The supply system 2 operates when the borehole 1 is excavated, and stops operating when the borehole 1 is filled with high viscosity mud. Further, the recovery line 3 operates when muddy water is replaced with concrete, and stops its operation when the muddy water in the excavation hole 1 is replaced with concrete.

The muddy water collected in the sand settling tank 6 is sent to the muddy water transport port 2 by a mud pump after the mixed sand and gravel are settled and separated.
2 and then returned to the mud storage tank 8.

If the slurry has deteriorated due to multiple uses, the recovered mud water is not sent to the sand settling tank 6 but is transferred to a waste liquid tank (not shown).

Therefore, after the supply/recovery lines 2 and 3 are in operation,
The mixer 4 only needs to mix enough mud to replenish the amount lost in the drilling hole 1 or the amount lost due to waste liquid separation, and replenish the mud storage tank 8 through the pipeline 24.

Here, as the viscous substance, a vegetable viscous substance such as guar gum or locust bean gum may be used alone or in combination, and both become viscous liquids when dissolved in water. This muddy water is then made even more viscous by a viscosity-enhancing agent, that is, an alkalizing agent, increasing the viscosity to tens of thousands of centipoises. is used. Further, the viscosity reducing agent in the storage tank 14 is an acidifying agent, such as aluminum sulfate,
Aluminum chloride, dilute sulfuric acid, dilute hydrochloric acid, etc. are used.

Therefore, the muddy water in the sand settling tank 6 becomes neutral or weakly acidic and is stored in a low viscosity state. Therefore, the settling action is promoted, and the sedimentation and accumulation of the slime 26 can be accelerated.

Removal of the slime 26 deposited on the bottom of the sand settling tank 6 will be explained using FIGS. 2 and 3 below.

The sand settling tank 6 is placed on a pedestal 28, and is slightly raised from the ground to obtain a flow head for slime flowing out from a slime removal port 30 which is openable and closable on the side near the bottom. That is, the slime removal port 30 is located on the side surface of the sedimentary layer of slime 26 to discharge mud from the sand settling tank 6 using water pressure.

A waste container 32 for receiving slime 26 is arranged below the slime removal port 30.

Note that the position of the slime removal port 30 is not limited to the side surface of the sand settling tank 6, but may be located at the bottom. In this case, the soil container 32 is placed between the elevated frames 28 and can be placed under the bottom of the sand settling tank 6 so as to be submerged under the sand settling tank 6.

The slime removal port 30 is opened and closed by using a vertically slidable plate-shaped frame material 34 that surrounds the opening drilled in the wall of the sand settling tank 6 and a U-shaped frame 34 that surrounds the wall with a slight lift from the wall. A lid 36 is fitted and fixed with bolts 38 screwed from the surface of the frame member 34 to the lid 36 and the wall surface of the sand settling tank 6.

Note that the bolts 38 for closing and fixing the lid 36 do not penetrate the wall of the sand settling tank 6, but are threaded into the frame material 34.
A structure may also be used in which the tip of the lid 36 is pressed against the surface of the lid 36.

When discharging the slime 26, remove the bolt 38 and remove the lid 3.
All you have to do is pull up 6.

However, when the slime removal port 30 is arranged on the side surface of the sand settling tank 6, the fluidity is poor due to the viscosity of the muddy water, and the accumulated slime 26 may not come out easily.

Therefore, as in the second embodiment shown in FIG. 3, a jet nozzle 40 (air spout) that spouts air at a high flow rate is arranged below the slime removal port 30, and a high-pressure air, for example, about 5 kg/cIIY, is provided. air from nozzle 40
From there, it is sprayed onto the slime 26.

A valve 41 is provided in the middle of the nozzle 40, and the nozzle 4 is opened by opening the valve 41.
This is to blow out compressed air that has been supplied to zero. Thereby, a forced fluid force can be applied to the deposited layer of slime 26, and soil removal from the slime removal port 30 can be promoted.

(Effects) As described above, according to the muddy water recovery system of the present invention, since the slime removal port is provided in the lower part of the sand settling tank so that it can be opened and closed, slime can be discharged as desired by opening and closing this removal port. Therefore, since a packet or a climb shell that occupies the upper surface of the sand settling tank 6 to discharge slime is not used, the top of the sand settling tank 6 can always be used as a work place.

In addition, removal work is possible even during muddy water circulation, and at the same time,
Since the soil is removed by natural fall, the removal process time is also quick.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a muddy water recovery system according to an embodiment of the present invention, FIG. 2(a) is a front view of a slime removal port, and FIG.
b) is a side vertical sectional view of FIG. 3(a), and FIG. 3 is a sectional view showing another embodiment of the slime removal port.

Claims (2)

[Claims] (1) In a recovery system constituting a recovery and reprocessing system for high viscosity muddy water used in the muddy water construction method, slime that receives the protrusion of a mud lifting pipe that sucks up the high viscosity muddy water from an excavation hole and is provided with a muddy water conveyance port. A sand settling tank, a mud storage tank that receives mud water from the conveyance port and mud water from a mixing line, etc. to which necessary ingredients and water are added as needed, and a mud storage tank that supplies the high viscosity mud water from the mud storage tank into the excavation hole. a mud water supply line that supplies
A muddy water recovery system comprising an openable and closable slime removal port provided at the bottom of the slime settling tank. (2) The muddy water recovery system according to claim 1, wherein the slime removal port is provided with an air jet port inserted at a lower portion thereof.