JP2002028698A - Method and device for separating soil and sand from drilled muddy water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for separating soil and sand from drilled muddy water, by which the soil and sand are made to meet a standard as surplus soil to unnecessitate treatment as industrial waste and the recycle of a sand part based on the sand and muddy water is realized by preventing the intermixture of a part of drilled muddy water in the soil and sand separated from the drilled muddy water, causing the sand and soil to be soft sludge. SOLUTION: In the basic means of the method and device for separating the soil and sand from the drilled muddy water, the soil and sand obtained as the result of drilling an underground hole 36 is lifted on the ground as the drilled muddy water with muddy water 37, the drilled muddy water is guided to a obliquely provided first vibration screen 21 to separate a pebble/clay part 40 from the drilled muddy water so accumulate it by forward sending vibration along a slope, the drilled muddy water having passed through the screen 21 is sent into a cyclone 33 and thickened muddy water discharged from a cyclone under part and including fine particles is guided to an obliquely provided second vibration screen 26 to separate a sand part in the thickened muddy water and to form the flock of the fine particles to accumulate non-fluid sand part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the construction of cast-in-place piles, underground continuous walls, etc., in which excavated soil excavated in underground holes and the like by fluid transport using muddy water is lifted to the ground as excavated muddy water and transported. Also, the present invention relates to a method and an apparatus for separating muddy muddy water, which make it possible to separate excavated sediment (gravel, clay and sand) from the muddy water and treat it as residual soil or to reuse it.

[0002]

2. Description of the Related Art Conventionally, when a cast-in-place pile or an underground continuous wall is constructed by a reverse construction method as a foundation work of various buildings, an underground hole extending to several tens of meters is excavated, and reinforcing bars are arranged. After that, a construction method is generally adopted in which a tremy tube is inserted, and ready-mixed concrete is sequentially poured into the concrete. As a method of excavating the underground hole, a method of excavating by an excavator while using a high concentration muddy water or a stable liquid by a reverse method or the like is generally performed. In such a construction method, a process of sucking excavated earth and sand excavated from an underground hole together with muddy water and lifting it up as excavated muddy water is carried out.

For example, a rod type and a hose drum type are generally used as a method of draining a fluid used when excavating by a continuous excavator. The rod type includes a method using a vertical multi-axial or horizontal multi-axial type sludge steel pipe, and the hose drum type includes a hose hanging method, a vertical winding method, and a horizontal winding method.

[0004] In the above-mentioned construction method, a step of lifting the excavated soil together with the muddy water as excavated muddy water on the ground and then separating the excavated sediment and muddy water from the excavated muddy water is indispensable. It is conceivable that the muddy water is reused as contaminants such as cement and the other mud is returned to the underground hole again to be reused as a stable liquid. Regarding the classification of residual soil and industrial waste (sludge) of excavated earth and sand from excavation of underground holes such as cast-in-place piles and underground continuous walls, etc. ", The following criterion is indicated. That is,
"For excavated materials that contain approximately 95% or more of particles exceeding 74 μm in diameter, the surplus soil can be easily removed of water. That do not hinder the preservation of the living environment. " On the other hand, "can not pile dump truck standards and sludge as referred to herein is a state that can not walk over the person, corn index substantially 200 kN / m ² or less in terms of the index indicating the strength of the soil or uniaxial compression Strength of about 50 kN / or less ". As described above, depending on whether the excavated earth and sand is recognized as surplus soil or sludge, the means, method, equipment, and cost of the treatment are greatly different.

FIG. 7 is a schematic view showing an example of a conventional sediment separating apparatus, and FIG. 8 is a perspective view of the same. In FIG. By passing through the vibrating screen 4 and the secondary vibrating screen 5, the gravels and clay 6 are separated by the primary vibrating screen 4 to which the vibrating force is applied by the vibrating motor 13, and the remaining soil pit 1 is separated.
The sediment 7 containing sand is separated from the drilling mud passing through the primary vibrating screen 4 by the secondary vibrating screen 5 and discharged into the residual soil pit 15 together with the gravel / clay 6. .

The vibrating screen is a device that stretches a screen having a mesh of a specific mesh and separates and transports gravel, clay and sand from drilling mud while vibrating the screen by a screen vibrator. .

[0007] The primary vibrating screen 4 and the secondary vibrating screen 5 are both provided with an inclined surface such that the inflow of excavated muddy water flows backward, that is, an upwardly inclined surface. Is temporarily stored in the lower tank 8 and stirred by the stirring pump 9 while the sand pump P
_1, the mud was concentrated by flowing into the cyclone 10, 11 rings by P _2, and supplies the concentrated mud on the secondary vibrating screen 5, upward along the inclined surface of the slope up by the transport effects associated with the vibration of the screen The sand 7 is dropped and separated from the end face of the secondary vibrating screen 5 while being moved, and is accumulated in the residual soil pit 15.

Mud water that does not contain microparticles corresponding to the supernatant of cyclones 10 and 11 is sent to circulation tank 12 as mud water for cyclone over, and is reused as mud water used for excavation of underground holes and the like. Excess muddy water that overflows on the primary vibrating screen 4 is collected by the weir 14 and discharged out of the tank, and is supplied again from the inlet 2 of the processing tank 1.

[0009]

However, in the conventional sediment separating apparatus, the first vibrating screen 4 is first passed through the first vibrating screen 4 and the second vibrating screen 5 which are arranged in a multi-stage manner. The sediment / clay component 6 is separated and discharged by means of a secondary vibrating screen 5, and the sand 7 is separated from the concentrated muddy water that has passed through the primary vibrating screen 4 and is concentrated by the cyclone. And is discharged into the same surplus soil pit 15. Therefore, the residual soil pit 1
In 5, the gravel / clay component 6 and the sand component 7 are mixed, and it is possible to satisfy the standard as the above-mentioned remaining soil, that is, the condition as the remaining soil which does not show fluidity but is not in a muddy state. However, there is a drawback in that it is necessary to dispose of the waste as industrial waste, and it is not possible to dispose the waste as ordinary residual soil.

Since the primary vibrating screen 4 and the secondary vibrating screen 5 are both provided with a rising slope before the inflow of drilling mud flowing backward, they are included in the gravel / clay component 6 and the sand component 7. In many cases, clogging of the mesh is apt to occur due to the viscous soil, and a part of the drilling mud flowing in with this flows down on the vibrating screen as it is and flows into the residual soil pit 15, and there are many cases in which In many cases, the sand 7 becomes soft and becomes sludge, which makes it difficult to determine the remaining soil of the excavated soil, and is a serious problem such as an increase in disposal costs in subsequent operations.

Therefore, the present invention solves the above problems,
By separately discharging the gravel, clay, and sand separated from the drilling mud, the excavated soil can be treated as ordinary residual soil, and the primary vibrating screen is used by viscous soil contained in the drilling mud during operation. And prevent the mesh of the secondary vibrating screen from clogging, thereby preventing a part of the drilling mud from mixing into the residual soil to form soft sludge, and easily setting the standard as the residual soil. It is an object of the present invention to provide a method and an apparatus for separating earth and sand from drilling mud, which can be filled to eliminate the need for treatment as industrial waste and facilitate subsequent operations.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention raises earth and sand excavated in an underground hole together with muddy water as excavated muddy water, and places the excavated muddy water on an inclined primary vibrating screen. To separate the gravel and clay from the drilling mud and accumulate it by forward vibration along the slope.
The drilling mud passed through the secondary vibrating screen is sent to the cyclone, and the concentrated mud of the cyclone under containing microparticles is guided to the slanted secondary vibrating screen to separate the sand in the concentrated mud and form flocs of microparticles And sediment separation method for drilling mud to accumulate sand that does not exhibit fluidity, and to separate and discharge gravel and clay in drilling mud 1
A secondary vibrating screen is arranged in parallel at a position adjacent to the secondary vibrating screen to provide a downward slope before the drilling mud flowing into the primary vibrating screen flows forward.
The next vibrating screen is provided with a slanted surface that makes it difficult for the muddy water flowing in to go forward in order to improve the dewatering property,
The excavated earth and sand is excavated together with the muddy water to the ground as excavated muddy water. The excavated muddy water is guided to the primary vibrating screen to separate the gravel and clay components from the excavated muddy water and accumulate by forward vibration along the slope. Then, the drilling mud passing through the primary vibrating screen is sent to the cyclone, and the concentrated mud of the cyclone under containing fine particles is guided to the secondary vibrating screen to separate sand in the concentrated mud and form flocs of fine particles. To provide a method for separating earth and sand from drilling mud that accumulates sand that does not exhibit fluidity.

[0013] A primary vibrating screen for separating and discharging gravel and clay components in the drilling mud, and a concentrated cyclone-under mud containing fine particles and fine particles from the drilling mud passing through the primary vibrating screen are not included. A cyclone that separates into the muddy water of the cyclone over and a sandstone in the concentrated muddy water of the cyclone under that is arranged in parallel adjacent to the primary vibrating screen and forms flocs of fine particles to exhibit fluidity And a secondary vibrating screen for accumulating undesired sand. The primary vibrating screen is provided with a downward slope before the inflowing drilling mud flows forward, while the secondary vibrating screen is provided with an inflowing muddy water that is difficult to move forward in order to improve dehydration. As a primary vibrating screen, a coarse mesh screen that separates and discharges gravel and clay from the excavated mud is used. As a secondary vibrating screen, sand in concentrated muddy water is used. A configuration employing a fine mesh screen that separates and discharges the minutes, the primary vibrating screen and the secondary vibrating screen are respectively mounted on a gantry,
A lower tank for storing the drilling mud passing through the primary vibrating screen is provided inside the gantry supporting the secondary vibrating screen, and a sand for supplying the mud passing through the primary vibrating screen to the cyclone in the lower tank. Provided is a configuration in which a pump is arranged.

Further, by arranging the primary vibrating screen and the secondary vibrating screen in parallel, the gravel / clay component separated by the primary vibrating screen and the sand component separated by the secondary vibrating screen are mixed. The present invention provides a configuration for separating and accumulating without separation, and a configuration for supplying mud of a cyclone over from which fine particles have been removed by a cyclone to a circulation tank to reuse as mud for excavation.

According to the method and the apparatus for separating the excavated muddy water, the muddy water used for excavating the underground hole as the foundation work of the structure is lifted to the ground as excavated muddy water together with the excavated muddy water to reduce the vibration force. When guided to the added primary vibrating screen, gravel and clay are separated from the excavated mud while flowing down on the slanted primary vibrating screen provided with a downwardly inclined surface, and forwarded along the inclined surface Accumulated by vibration. The drilling mud passing through the primary vibrating screen is sent to a lower tank provided inside a gantry supporting the secondary vibrating screen, and is discharged by a sand pump in the lower tank.
It is then fed into a cyclone located above the vibrating screen. The drilling mud is separated into individual liquids by using a cyclone at a splitting point of 74 μm. The concentrated mud of the cyclone under containing fine particles is led to the secondary vibrating screen to separate the sand in the concentrated mud and the fine particles of 74 μm or more are floc. And accumulate sand that does not exhibit fluidity.

That is, on the secondary vibrating screen provided with the upwardly inclined surface, the sand in the concentrated mud is separated, and the fine particles combine with each other to form flocs, which are conveyed by the vibration of the screen. Drops by action and accumulates as sand. The muddy water that has passed through the secondary vibrating screen is again stored in the lower tank and sent back into the cyclone to separate it into cyclone-over muddy water equivalent to the supernatant liquid and concentrated cyclone-under concentrated sludge repeatedly. Will be Cyclone-over mud containing no fine particles of 74 μm or more can be reused as mud when excavating an underground hole.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A concrete embodiment of a method and an apparatus for separating earth and sand from drilling mud according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram for explaining a sediment separating method according to the present embodiment, FIG. 2 is a perspective view showing a sediment separating apparatus according to the present embodiment, FIG. 3 is a plan view thereof, FIG. 4 is a front view thereof, and FIG. 4 is a view as viewed from the direction of the arrow A, and FIG. 6 is a view as viewed from the direction of the arrow B in FIG. 4. First, the configuration of the apparatus will be described with reference to FIGS.

Reference numeral 21 denotes an inclined primary vibrating screen, which is configured so that a vibrating force is applied to the primary vibrating screen 21 by a vibrating mechanism using a vibrating motor 22 and a belt 23. Reference numeral 24 denotes an inflow port for excavated muddy water, and reference numeral 25 denotes a gantry for supporting the primary vibrating screen 21. The primary vibrating screen 21 has a function of separating and discharging the gravel and clay components in the excavated muddy water, and the screen itself employs a relatively coarse mesh screen of about 5 mm. The primary vibrating screen 21 is provided with an inclined surface such that the inflowing drilling mud flows as it is, that is, a downwardly inclined surface.

Reference numeral 26 denotes a slanted secondary vibrating screen. The secondary vibrating screen 26 is arranged in parallel at a position adjacent to the primary vibrating screen 21, and is driven by a vibrating motor 27 and a belt 28. The secondary vibrating screen 2
6 is configured to apply a vibration force. Reference numeral 29 denotes a gantry for supporting the secondary vibrating screen 26. Inside the gantry 29, a lower tank 30 for storing the muddy water that has passed through the primary vibrating screen 21 is provided. 31 are arranged. 3
Reference numeral 2 denotes a feed pipe for feeding the drilling mud passing through the primary vibrating screen 21 to the lower tank 30.

A submersible pump with stirring blades is used as the sand pumps 31, 31. Generally, it is necessary to provide a stirrer in the lower tank 30. However, the use of the submersible pump with the stirring blade makes the stirrer unnecessary.

The secondary vibrating screen 26 has a function of separating and discharging sand in sludge, and a relatively fine mesh screen of about 640 μm is used as the screen. The vibrating screen 26 is provided with an inclined surface in which the inflowing drilling mud does not flow forward as it is but flows backward, that is, an inclined surface that rises forward.

Reference numerals 33, 33 denote cyclones arranged above the secondary vibrating screen 26, and the lower tank 30
The other ends of the feed pipes 34 derived from the sand pumps 31, 31 disposed in the inside are connected to the cyclones 33, 33. Reference numeral 35 denotes a discharge port of the muddy water of the cyclone 33, which is over the cyclone.

The cyclones 33, 33 capture fine particles having a diameter of more than 74 μm and pass them through the secondary vibrating screen 26 as concentrated mud of cyclone under, in order to identify the limit of sludge that does not exhibit fluidity. 74 μm
Has the function of passing muddy water that does not contain fine particles exceeding the above-mentioned amount to the discharge port 35 as muddy water for the cyclone over.

The operation of the earth and sand separating apparatus according to the present embodiment will be described with reference to the schematic diagram of FIG. 1 and the detailed diagrams of FIGS. First, in order to construct a cast-in-place pile as a foundation work of a building by a reverse method, an underground hole 3 shown in FIG.
6 is excavated by the excavator 38 using the mud 37, and the excavated excavated earth and sand is lifted to the ground as excavated mud by the suction action of the sand pump 39 together with the mud 37, and is discharged from the inlet 24 to the primary. Guided by the vibrating screen 21, the vibration motor 22 and the belt 23 (see FIG. 2)
As a result, a downwardly inclined surface is provided while the vibrating force is applied to flow down the primary vibrating screen 21 which is obliquely provided.

As described above, since a relatively coarse mesh screen of about 5 mm is used for the primary vibrating screen 21, the gravel / clay component 40 separated from the excavated muddy water moves forward along the inclined surface. The drilling mud passing through the mesh screen is passed through a feed pipe 32 to support the secondary vibrating screen 26.
9 is sent to the lower tank 30 arranged inside.
Since the accumulated gravel / clay component 40 does not contain a sludge component, it can be directly disposed of as “remaining soil”.

The drilling mud sent into the lower tank 30 is supplied to a sand pump 3 placed in the lower tank 30.
1, 31 are fed through a feed pipe 34 into cyclones 33, 33 arranged above the secondary vibrating screen 26. The cyclones 33, 33 capture fine particles having a diameter of not more than 74 μm, which do not exhibit fluidity, and concentrate and pass on the secondary vibrating screen 26 as concentrated muddy water of cyclone under. On the other hand, only the mud corresponding to the supernatant liquid containing no fine particles exceeding 74 μm flows out of the discharge port 35 as mud of cyclone over and flows out of the circulation tank 4.
Stored in 1.

The secondary vibrating screen 26 is a mesh screen with a fine mesh of about 640 μm. While the sand is separated, the fine particles of 74 μm or more captured by the cyclones 33, 33 are combined with each other to form flocs and captured, and the vibration motor 27 and the belt 28 (FIGS. 4, 6)
(See FIG. 1) and fall down while moving upward along the inclined surface to accumulate as sand 42 (see FIG. 1). Since the accumulated sand 42 is mainly composed of sand, it can be reused as a material such as soil cement, or can be directly discarded as “remaining soil”.

Further, since the secondary vibrating screen 26 is provided with the upwardly inclined surface, the excavated mud fed into the secondary vibrating screen 26 is temporarily stored in the lower tank 30 without flowing down in the direction of the sand 42. The stored muddy water is fed into the cyclones 33, 33 again by the sand pumps 31, 33 and separated into the cyclone over muddy water corresponding to the supernatant liquid and the concentrated cyclone under muddy water. The cyclones 33, 33
The muddy water of the cyclone over which does not contain fine particles having a diameter exceeding 74 μm and flows out from the discharge port 35 of the reservoir and is stored in the circulation tank 41 is muddy water 3 used when excavating the underground hole 36.
7 is reusable.

As described above, according to the present invention, the primary vibrating screen which is provided with the downwardly inclined surface is provided by lifting the muddy water used for excavating the underground hole together with the excavated earth and sand to the ground. Separation of gravel and clay is separated by natural fall along the slope, and the excavated mud is sent from the lower tank into the cyclone placed above the secondary vibrating screen by a sand pump and does not exhibit fluidity. The fine particles are passed through a secondary vibrating screen as a concentrated muddy water of a cyclone under, and the sand in the excavated muddy water is separated on the secondary vibrating screen, and the floc of fine particles is formed, and the sand that does not exhibit fluidity is formed. It is an operational feature that the muddy water corresponding to the supernatant liquid containing no fine particles is stored as the muddy water of the cyclone and reused.

[0030]

As described above in detail, according to the present invention, since the primary vibrating screen and the secondary vibrating screen are arranged adjacently and in parallel, the gravel / clay discharged from the primary vibrating screen. And the sand discharged from the secondary vibrating screen can be separated and accumulated, thereby preventing the mixture of gravel / clay and sand with the excavated soil. The condition as “remaining soil” that no longer exhibits fluidity but in a state can be easily satisfied, so that sludge treatment as industrial waste is not required, and normal “remaining soil” disposal can be performed. Gravel, clay and the like discharged from the primary vibrating screen can also be treated as “remaining soil”, and do not correspond to sludge as industrial waste.

The drilling mud passing through the primary vibrating screen is sent from the lower tank by a sand pump into a cyclone arranged above the secondary vibrating screen, and is supplied to the tank.
Using the μm as a dividing point, the microparticles that do not exhibit fluidity are passed through a secondary vibrating screen as concentrated cyclone underwater, and the mud corresponding to the supernatant liquid that does not contain microparticles is reused as cyclone over mud. Can be offered.

By making the primary vibrating screen a screen which is lowered forward, gravel and clay are smoothly discharged and there is no clogging of the screen, and a layer of clay is formed on the screen due to clogging. Drilling mud does not flow over it. By forming the secondary vibrating screen in a forward rising configuration, sand in the excavated mud is separated on the secondary vibrating screen, and fine particles are combined with each other to form flocs, which accompany the vibration of the screen. Due to the transporting action, it can fall while moving upward along the inclined surface and accumulate as sand.
Since the accumulated sand is mainly composed of sand, it can be reused as a material such as soil cement or can be disposed of as "remaining soil" as it is.

Therefore, according to the present invention, the excavated earth and sand can be discarded as ordinary residual soil by separately discharging the sand separated from the excavated mud and the gravel and clay, and can be included in the excavated earth and sand. Clogging of the meshes of the primary vibrating screen and the secondary vibrating screen does not occur due to the viscous soil that is generated, it is easy to determine the remaining soil of the excavated earth and sand, and it is possible to process the excavated earth as “remaining earth”, and the accumulated The sand content and muddy water of the cyclone over have many effects that can be reused.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining a method for separating earth and sand according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a sediment separating apparatus according to the present invention.

FIG. 3 is a plan view showing the earth and sand separation device.

FIG. 4 is a front view showing the earth and sand separation device.

FIG. 5 is a view taken in the direction of the arrow A in FIG. 4;

FIG. 6 is a view taken in the direction of arrow B in FIG. 4;

FIG. 7 is a schematic diagram showing an example of a conventional earth and sand separation device.

FIG. 8 is a perspective view showing an example of a conventional earth and sand separation device.

[Explanation of symbols]

 21 ... Primary vibrating screen 22,27 ... Exciting motor 24 ... Inlet 25,29 ... Stand 26 ... Second vibrating screen 30 ... Lower tank 31 ... Sand pump 32,34 ... Supply pipe 33 ... Cyclone 35 ... Exhaust Exit 36 ... Underground hole 37 ... Muddy water 38 ... Excavator 41 ... Circulation tank 42 ... Sand content Reference number P3088

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B03B 5/28 B03B 7/00 7/00 E21B 21/06 E21B 21/06 B01D 23/02 A

Claims (11)

[Claims] 1. The earth and sand excavated in an underground hole is lifted to the ground as excavated mud together with mud and separated from the excavated mud by a primary vibrating screen to accumulate gravel and clay.
The drilling mud passed through the primary vibrating screen is sent to the cyclone, and the concentrated mud of the cyclone under containing fine particles is guided to the secondary vibrating screen to separate the sand in the concentrated mud and form flocs of fine particles. A method for separating earth and sand from drilling mud, comprising accumulating sand that does not exhibit fluidity. 2. The earth and sand excavated in the underground hole is lifted to the ground as muddy water together with the muddy water, and the excavated muddy water is guided to a slanted primary vibrating screen to separate gravel and clay from the excavated muddy water and to be inclined. While accumulating by the advance vibration along the surface,
The drilling mud passing through the primary vibrating screen is sent to the cyclone, and the concentrated mud of the cyclone under containing fine particles is guided to the slanted secondary vibrating screen to separate the sand in the concentrated mud and to flocculate the fine particles. A method for separating earth and sand from drilling mud, comprising forming and accumulating sand that does not exhibit fluidity. 3. A secondary vibrating screen is arranged in parallel at a position adjacent to the primary vibrating screen for separating and discharging the gravel and clay components in the drilling mud, and the drilling mud flowing into the primary vibrating screen is directed forward. On the other hand, the secondary vibrating screen is provided with a downward slope that makes it difficult for the inflow muddy water to move forward. At the same time, it was lifted to the ground as excavated mud, guided the excavated mud to the primary vibrating screen, separated from the excavated mud by gravel and clay, accumulated by forward vibration along the slope, and passed through the primary vibrating screen The drilling mud is sent to the cyclone, and the concentrated mud of the cyclone under which contains fine particles is guided to the secondary vibrating screen to separate the sand in the concentrated mud and form flocs of fine particles to flow. A method for separating earth and sand from drilling mud, comprising accumulating non-moving sand. 4. By arranging the primary vibrating screen and the secondary vibrating screen in parallel, the gravel / clay component separated by the primary vibrating screen and the sand component separated by the secondary vibrating screen are mixed. 4. The method for separating muddy water according to claim 1, 2 or 3, wherein the excavated muddy water is separated and accumulated. 5. The method of claim 1, 2, 3 or 4, wherein the muddy water of the cyclone over from which fine particles have been removed by the cyclone is supplied to a circulation tank and reused as muddy water for drilling. 6. A primary vibrating screen for separating and discharging the gravel and clay components in the drilling mud, and excluding the concentrated mud and fine particles of cyclone under containing fine particles from the drilling mud passing through the primary vibrating screen. A cyclone that separates into the muddy water of the cyclone over and a sandstone in the concentrated muddy water of the cyclone under that is arranged in parallel adjacent to the primary vibrating screen and forms flocs of fine particles to exhibit fluidity And a secondary vibrating screen for accumulating unremoved sand. 7. The primary vibrating screen is provided with a downwardly inclined surface on which the inflowing drilling fluid flows forward,
The excavated muddy sediment separating apparatus according to claim 6, wherein the secondary vibrating screen is provided with a forwardly inclined surface that makes it difficult for the inflow of muddy water to move forward in order to improve dewatering properties. 8. A coarse mesh screen which separates and discharges gravel and clay in the drilling mud as a primary vibrating screen, and separates sand in concentrated mud as a secondary vibrating screen. The earth and sand separation device for drilling mud according to claim 6 or 7, wherein a fine mesh screen is used for discharging. 9. A lower part for placing a primary vibrating screen and a secondary vibrating screen on a gantry, respectively, and for storing a drilling mud passing through the primary vibrating screen inside a gantry supporting the secondary vibrating screen. 9. The sediment separation apparatus for excavated mud according to claim 6, further comprising a tank, and a sand pump for supplying muddy water having passed through the primary vibrating screen to the cyclone in the lower tank. 10. By arranging the primary vibrating screen and the secondary vibrating screen in parallel, the gravel / clay component separated by the primary vibrating screen and the sand component separated by the secondary vibrating screen are mixed. 10. The earth and sand separating device for drilling mud according to claim 6, 7, 8 or 9, wherein the sediment is separated and collected without being separated. 11. The muddy water of a cyclone over from which fine particles have been removed by a cyclone is supplied to a circulation tank and reused as muddy water for excavation.
The excavation mud sediment separation apparatus according to 0.