JP6304730B1 - Mud discharge promotion device and ground improvement method - Google Patents

Abstract

Disclosed is a waste mud discharge promoting device capable of preventing a situation in which waste mud is smoothly discharged to the ground side through a waste mud discharge route and foreign matter is blocked, and the waste mud discharge promoting device. Providing ground improvement method using slag. An improved body is created by injecting a solidified material from a solidified material injection rod inserted into a drilled borehole and moving the solidified material injection rod in the axial direction while rotating or rotating. In this case, in the waste mud discharge promoting device arranged in the region of the ground side end portion of the boring hole in order to facilitate the flow of the waste mud from which the waste mud containing the solidified material and the in-situ soil is discharged to the ground side, The solidifying material injection rod is configured separately from the air pipe having an injection port for injecting fluid at the tip and a fluid supply port communicating with the fluid supply source, and the lower end is above the improved top. The dimension in the axial direction is set so as to be located at the position, and the fluid is jetted from the jet port of the air pipe into the waste mud discharge path to form a fluid flow, and the fluid flow is added to the waste mud flow. [Selection] Figure 4

Description

  The present invention moves in the axial direction while rotating or rotating the solidifying material injection rod while injecting the solidifying material from a solidifying material injection rod (for example, a multi-tube rod) inserted into the bored hole. Then, it is used in the high pressure jet agitation ground improvement method to create an improved body (raised or lowered), and the mud (slime) containing solidified material and in-situ soil is discharged to the ground side through the borehole. Related to technology that promotes

In the ground improvement method, for example, as shown in FIGS. 9 and 10, after cutting the ground and drilling the borehole H to a predetermined depth, the solidifying material injection rod 11 (for example, a double pipe) of the ground improvement device 100 is used. Rod (multi-tube rod) is inserted into the boring hole H, the solidification material injection rod 11 is rotated to the ground side (arrow A), and the solidification material slurry (from the solidification material injection nozzle of the solidification material injection rod 11) Cement milk or the like) is jetted (symbol J) to form the improved body K.
At that time, the highly viscous waste mud composed of in-situ soil (for example, clay) and the solidifying material slurry (cement milk, etc.) basically corresponding to the amount of the solidifying material slurry to be injected is the outer peripheral surface of the solidifying material injection rod 11. Is discharged to the ground side (arrow B) through a mud discharge route constituted by an annular space (clearance) between the inner periphery of the borehole H and the borehole H.

However, if the in-situ soil is highly viscous or if foreign matter (clay lump, piece of wood, etc.) is present in the mud, the mud discharge route may be blocked as shown in FIG. In FIG. 10, a foreign matter (clay lump, wood piece, etc.) and a location blocked by the mud (blocked location) are indicated by the symbol C. In FIG. 11 which shows the detail of this obstruction | occlusion location C, the piece of wood etc. and the clay lump which are obstruct | occluding the waste mud discharge path are shown by the code | symbol S. In FIG.
When the mud discharge route is blocked, the injection pressure from the solidifying material injection rod 11 acts on the ground side through the surrounding ground (arrow D in FIG. 10), as shown in FIG. ) Occurs.
In order to prevent the ground from rising, when the mud discharge route is blocked by mud or foreign matter (clay lump, piece of wood, etc.), the injection of the solidified material from the solidified material injection rod 11 is interrupted and the solidified material injection rod 11 is pulled up. The construction is resumed after the closed state is released by injecting water to the closed part C. However, if the injection of the solidifying material from the solidifying material injection rod 11 is interrupted, the quality of the underground solidified body is deteriorated. Therefore, it is desirable to avoid the injection of the solidifying material as much as possible. Further, since a large amount of water is jetted to release the closed state of the closed portion C, there is a problem that the amount of mud is increased by that amount of water.

  As another conventional technique, there is a technique in which welan gum is added to a hardened material when a cylindrical solid body is formed in the ground (see Patent Document 1). Although this technology is useful, it is a technology aimed at improving the material separation resistance of the hardened material without reducing the fluidity of the waste mud, and is not intended to solve the problems as described above. .

Japanese Patent Laid-Open No. 7-76821

  The present invention has been proposed in view of the above-described problems of the prior art. Even when the viscosity of the mud is high or when foreign matter (for example, a piece of wood or a clay lump) is mixed, the mud is removed together with the foreign matter. An object of the present invention is to provide a waste mud discharge promoting device that can be smoothly discharged to the ground side through the waste mud discharge route and prevent the waste mud discharge route from being blocked, and a ground improvement method using the device. It is said.

The waste mud discharge promoting device (10) of the present invention solidifies while injecting a solidified material from a solidified material injection rod (11: for example, a multi-tube rod) inserted into the bored hole (H). When forming the improved body (K) by moving (raising or lowering) the material injection rod (11) in the axial direction while rotating or rotating, the mud containing the solidified material and the in-situ soil is generated. In the waste mud discharge promoting device (10) disposed in the region of the ground side end of the boring hole (H) in order to facilitate the flow of the mud flow discharged to the ground side,
The solidifying material injection rod (11) is configured separately.
An injection tube (air tube 1) having an injection port (1A) for injecting fluid (for example, air, water, etc.) at the tip (underground side end), and a fluid supply port (2A: for example, communicating with a fluid supply source) Air supply port)
The axial dimension is set so that the lower end is located above the improved top (KA),
A fluid is ejected from the ejection port (1A) of the ejection pipe (1) into the mud discharge route (DR) to form a fluid flow, and the fluid flow is added to the waste mud flow.

In the said waste mud discharge promotion apparatus (10) of the present invention,
Regarding the injection direction of the fluid flow, the solidified material injection rod (11) is a waste mud discharge promoting device provided with the injection pipe (1) whose axial radial direction is a substantially tangential direction around the solidified material injection rod (11). It is a feature.

Moreover, in the said waste mud discharge | emission promotion apparatus (10) of this invention,
Regarding the injection direction of the fluid flow, the solidifying material injection rod (11) axial direction is the injection pipe (for example, the direction excluding the vertical underground direction) on the ground improvement device (100) side when the fluid to be injected is liquid. It is characterized by being a mud discharge promoting device equipped with 1).

In the present invention, if the ground side end of the boring hole (H) is drilled in the bottom of the pit (20: dredge), the mud discharge promoting device (10) of the present invention is connected to the bottom of the pit (20). It arrange | positions in the said boring hole (H).
Or in this invention, if the guide pipe (21) is arrange | positioned at the ground side edge part of a boring hole (H), the waste mud discharge | emission promotion apparatus (10) of this invention will be from the ground side edge part of a guide pipe (21). It arrange | positions so that it may extend inside a guide pipe (21). The position of the injection port (1A) of the mud discharge promoting device (10) may be in the guide pipe (21) or in a position away from the guide pipe (21).

In the waste mud discharge promoting device (10) of the present invention, a plurality of the injection pipes (1) can be provided, and a spacer (3) that keeps the interval between the plurality of injection pipes (1) can be arranged.
Moreover, in the said waste mud discharge | emission promotion apparatus (10) of this invention, the cross-sectional area of the injection port (1A) of the said injection pipe (1) can be made smaller than cross-sectional areas other than an injection port (1A).
Furthermore, in the said waste mud discharge | emission promotion apparatus (10) of this invention, the number of the said injection pipes (1) is comprised so that a number may be increased / decreased according to the size of the diameter of a solidification material injection rod (11). I can do it. In addition, according to the size of the hole diameter of the improved body, the injection amount per unit time of the solidified material or the injection amount per unit length in the depth direction of the improved body, and the diameter of the guide pipe (21), etc. It can comprise so that the number of pipes (1) may be increased or decreased.

In the said waste mud discharge | emission promotion apparatus (10) of this invention, it has a non-return valve function for preventing a waste mud from flowing back into the flow path of the said injection pipe (1) or a discharge outlet (1A). I can do it.
Moreover, in the said waste mud discharge | emission acceleration | stimulation apparatus (10) of this invention, the length of the said injection pipe (1) is set from the creation lowest end depth of an improvement body, and improvement body formation growth, and is injecting the solidification material. Depending on the depth, it can be adjusted to a length that is effective for promoting mud discharge.

And the ground improvement construction method of the present invention is to inject a solidified material injection rod (11: for example, a multi-tube rod) while injecting a solidified material from a solidified material injection rod (11: for example, a multi-tube rod) inserted into the bored hole (10). 11) When the improved body (K) is formed by moving (raising or lowering) in the axial direction while rotating or rotating, the mud containing solidified material and in-situ soil is discharged to the ground side. In the waste mud discharge promoting device that facilitates the flow of waste mud flow,
An injection pipe (1) configured separately from the solidifying material injection rod (11) and having an injection port (1A) for injecting a fluid (for example, compressed air, water, etc.) at the tip (underground side end). And a fluid supply port (2A: for example, compressed air supply port) communicating with the fluid supply source, the axial dimension is set so that the lower end portion is located above the improved top end (KA),
A waste mud discharge facilitating device (10) for injecting a fluid from the injection port (1A) of the jet pipe (1) into a mud discharge route (DR) to form a fluid flow and adding the fluid flow to the waste mud flow. In the region of the ground side end of the boring hole (H),
When the mud is discharged to the ground side, fluid is ejected from the jet port (1A) via the fluid supply source, the fluid feed port (2A), and the jet pipe (1) to discharge the mud. It is a ground improvement method characterized by promoting.

In the injection direction of the fluid flow of the injection pipe (1) of the waste mud discharge promoting device used in the ground improvement method of the present invention, the solidified material injection rod (11) axial radial direction is around the solidified material injection rod (11). Disposing a mud discharge promoting device configured to be in a substantially tangential direction in the region of the ground side end of the boring hole,
When drainage mud is discharged to the ground side, the ground improvement construction method promotes the discharge of mud by injecting fluid from the jet port through the fluid supply source, the fluid supply port, and the air pipe.

Moreover, in the injection direction of the fluid flow of the injection pipe (1) of the mud discharge promoting device used in the ground improvement method of the present invention, the solidified material injection rod (11) is axially directed so that the fluid to be injected is liquid. If the ground improvement device (100) side (for example, the direction excluding the vertical underground direction) is arranged in the region of the ground side end portion of the boring hole, the waste mud discharge promoting device is arranged,
When drainage mud is discharged to the ground side, the ground improvement construction method promotes the discharge of mud by injecting fluid from the jet port through the fluid supply source, the fluid supply port, and the air pipe.

Furthermore, in the said waste mud discharge | emission acceleration | stimulation apparatus used for the ground improvement construction method of this invention, the said injection pipe (1) is provided with two or more, and the space | interval of several injection pipes (1) is hold | maintained with a spacer (3). I can do it.
Moreover, the number of the said injection pipes is arrange | positioned by increasing / decreasing a number according to the magnitude of the diameter of the solidification material injection rod (11).
Moreover, as for the said injection pipe (1) used in the said sludge discharge | emission acceleration | stimulation apparatus of the ground improvement construction method of this invention, the cross-sectional area of the injection port (1A) is narrower than the cross-sectional area of an injection pipe (1) pipe body. Can be made smaller.

The said waste mud discharge | emission promotion apparatus used for the ground improvement construction method of this invention has a non-return valve function for preventing a waste mud from flowing back in the flow path of the said injection pipe (1).
Moreover, the length of the said injection pipe (1) is set from the formation lowest end depth and improvement body growth of an improved body, and is effective length in drainage discharge promotion according to the depth which is injecting the solidification material. Can be adjusted.

  By using the mud discharge promoting apparatus of the present invention having the above-described configuration, fluid (for example, compressed air) is jetted from the jet port (1A) of the jet pipe (1), and the depth direction of the jet port (1A) Is a narrow space (sludge discharge route) formed by an inner surface of the boring hole (H) and the outer surface of the solidifying material injection rod (11) (or formed by the inner surface of the guide pipe and the outer surface of the solidifying material injection rod). The fluid jetted into DR) becomes a fluid flow, and the fluid flow is added to the mud flow in which the mud containing the solidified material and the in situ soil is discharged to the ground side. By forming the fluid flow, the injection pressure, gas expansion pressure, and buoyancy are generated, and the applied excess pressure rises to escape to the ground side where the pressure is weak, forming a normal flow of mud flow, When the generated fluid rises (flows to the ground improvement device (100) side), the mud is entrained and discharged from the ground mud discharge port (2B). Further, a hose or the like is connected to the mud discharge port (2B) and connected to a mud storage facility (a mud tank) (not shown), so that the mud pressure applied by the fluid flow can be made smoothly. It is stored in the ground mud tank, and the mud processing work can be simplified. In this way, since the flow of waste mud generated during the development of the improved body is discharged (ascended) to the ground side, even if foreign matter (such as wood chips or clay lumps) exists in the waste mud, the foreign matter At the same time, the mud is raised to the ground side and discharged, and the mud discharge route (DR) constituted by the annular space between the inner wall surface of the boring hole (H) and the outer peripheral surface of the solidifying material injection rod (11) is blocked. Is prevented (suppressed).

A fluid (for example, compressed air) is injected from the injection port (1A) of the injection pipe (1) of the mud discharge promoting apparatus of the present invention. As described above, the position in the depth direction of the injection port (1A) is formed by the inner surface of the boring hole (H) and the outer surface of the solidified material injection rod (11) (or the inner surface of the guide pipe and the outer surface of the solidified material injection rod. It is an annular space formed). The annular space corresponds to a sludge discharge route (DR) of the sludge to the ground, and the depth direction position of the injection port is set near the start point or the middle point of the sludge discharge route (DR). Thus, in the conventional ground improvement method in which there is no fluid ejection from the waste mud discharge promoting apparatus of the present invention, highly viscous waste mud flows toward the ground in this narrow waste mud discharge path.
On the other hand, when fluid is injected and added from the waste mud discharge promoting device of the present invention, the fluid flow from the waste mud discharge promoting device is added to this highly viscous waste mud flow (fluid after fluid addition), When the effect of accelerating the flow and, for example, air is used as the fluid, the apparent viscosity of the mud after addition of the fluid becomes smaller than that of the conventional mud, and the drainage mud discharge promoting effect is exhibited.

Here, for example, when air or the like is injected from the side of the solidifying material injection rod (11), the air or the like is injected from a deep position, and the air is radially outward of the boring hole (H). There is a risk of intruding into the area. In that case, a region radially outward of the boring hole (H) is raised to cause inconvenience of destroying the pavement on the ground surface, or inconvenience of collapsing the hole wall of the boring (H). is assumed.
The waste mud discharge promoting device (10) in the present invention is configured separately from the solidifying material injection rod (11), and the axial dimension is set so that the lower end portion is positioned above the improved top end (KA). In the injection direction of the fluid flow from the injection port (1A) of the injection pipe (1), the axial direction of the solidified material injection rod (11) is substantially tangential around the solidified material injection rod (11). In this way, the injection port of each injection pipe is manufactured and installed in the borehole.
That is, the injection of the fluid solidifying material injection rod (11) in the axial radial direction is not directed outward in the radial direction, but is performed in a substantially tangential direction. Since the injection pipe (1) itself is in an annular space formed by the inner surface of the boring hole (H) and the outer surface of the solidified material injection rod (11) (or formed by the inner surface of the guide pipe and the outer surface of the solidified material injection rod), The injection in the substantially tangential direction around the solidifying material injection rod (11) means that it is radiated along the ring in this ring, and the injection port (1A) as shown in FIG. Is directed to a uniform tangential direction, so that the waste mud after the fluid addition forms a swirling flow. By making the swirl flow, the centrifugal force acting on the discharged mud after the fluid addition balances with the radial pressure gradient, and generation of excessive radial force can be prevented. This phenomenon can be explained by an example of balancing the centrifugal force with the bank of a bicycle running on an oval track. However, the injection port (1A) position of the exhaust mud discharge promoting device (10) does not necessarily have to be directed in a uniform tangential direction in each injection pipe, for example, when the position is in the guide pipe in the exhaust mud discharge path (DR). .

Furthermore, in the injection direction of the fluid flow from the injection port (1A) of the injection pipe (1), when the fluid to be injected is liquid in the axial direction of the solidified material injection rod (11), the ground improvement device (100) The fluid is ejected toward the side (for example, the direction excluding the vertical underground direction).
That is, the direction excluding the vertical underground direction indicates a direction as shown in F of FIG. 5 and indicates a direction in which the tube axis direction vector faces the ground side in the injection direction.
When the fluid to be ejected is a liquid, the ejected fluid may be mixed into the unconsolidated improved body, leading to a deterioration in the quality of the improved body. Therefore, as described above, the ground improvement device (100) side (for example, , In the direction excluding the vertical underground direction).
On the other hand, when the fluid to be ejected is a gas, it is not necessary to ask the directionality of the ejection in the axial direction of the solidified material ejection rod (11). When the fluid to be ejected is gas, the specific gravity is obviously small with respect to the waste mud, so that an effect due to buoyancy can be expected, and the ejection direction of the ejection port (1A) of the ejection pipe (1) is directed to the vertical underground direction. This is because the jetted fluid is directed to the ground side.
The injection direction of the injection port (1A) of the injection pipe (1) is preferably directed to the ground side in order to promote the discharge of waste mud to the ground. Smooth insertion into the annular space formed by the inner surface of the hole (H) and the outer surface of the solidifying material injection rod (11) (or formed by the inner surface of the guide pipe and the outer surface of the solidifying material injection rod). It is necessary to determine the shape of the injection port (1A) so as to exhibit the above.
As mentioned above, by giving direction to the jet fluid, it is possible to exert an effect of promoting the discharge of mud, smooth discharge of mud, occurrence of stagnation and blockage of mud, and troubles associated with this. Can be prevented.

Here, when the mud is discharged to the ground side, the discharge port (1A) side end portion of the injection pipe (1) moves inward in the radial direction, and the interval between the plurality of injection pipes (1). May become narrower. In such a state, the plurality of injection pipes (1) that have moved inward in the radial direction and whose intervals are narrowed prevent the mud from flowing out to the ground, causing the mud to stay and block. There is a fear.
In the present invention, if a plurality of the injection pipes (1) are provided, and a spacer (3) is provided to maintain a distance between the plurality of injection pipes (1), the injection pipe (1) is moved in the radial direction by the spacer (3). It is prevented that the space | interval becomes small. Similarly, it is possible to prevent the distance from increasing in the outward movement in the radial direction. Therefore, the outflow of the waste mud to the ground side is not inhibited, and the retention and blockage of the waste mud is prevented.
In addition, by arranging the spacer (3) that keeps the intervals between the plurality of injection pipes (1), a predetermined cylindrical space can be secured in the center of the cross section of the waste mud discharge promoting device, and solidified material injection is performed in this space. The rod (11) can be inserted and removed smoothly.

  The number of the injection pipes (1) is arranged by increasing or decreasing the number according to the diameter of the solidifying material injection rod (11). In the high-pressure injection agitation method, when the improved diameter increases, the bore hole (H) diameter and the solidified material injection rod (11) diameter basically increase, and the solidified material injection amount also increases. The amount of mud also increases. Along with this tendency, the number of the injection pipes is adjusted by adjusting the flow rate of the fluid injected from the injection port (1A) by setting the diameter of the solidified material injection rod (11) according to the size of the solidification material injection rod (11). Smooth outflow of mud flowing according to the size of the annular space formed by the inner surface of the hole (H) and the outer surface of the solidifying material injection rod (11) (or formed by the inner surface of the guide pipe and the outer surface of the solidifying material injection rod) Yes.

  Further, if the cross-sectional area of the injection port (1A) of the injection pipe (1) is made smaller than the flow path cross-sectional area of the injection pipe other than the injection port (1A), the fluid injected near the injection port (1A) In addition, it is possible to prevent foreign matter from entering the injection pipe (1) from the injection port (1A) when the fluid is not injected.

  Further, by providing a check valve in the flow path of the injection pipe (1), the waste mud flows backward from the injection port (1A) of the injection pipe (1), and the injection pipe ( 1) Blockage of itself can be prevented. This prevents a situation where a clay lump or the like flows backward and closes at the injection port of the injection pipe before the operation of the apparatus for promoting mud discharge.

Further, the length (in the pipe axis direction) of the injection pipe (1) is set from the lowest depth of formation of the improved body and the improved body growth, and promotes the discharge of mud according to the depth of injection of the solidified material. It can be adjusted to an effective length.
The improvement depth of the improved high pressure jet agitation method is, for example, the improvement of the bottom of deep shafts. There are various cases such as when the depth of the lower end is deep and the growth of the improved body is long. The sludge discharge promoting device adjusts the length of the injection pipe (1) so as to meet these conditions.
Basically, the lower end position of the injection pipe (1) is adjusted to the length of the injection pipe set so as to be located on the ground side from the top of the improved body, and the mud discharge promoting device itself may enter the improved body. Set to not. However, when the improved body growth is long, the length of the injection pipe is determined only by the top depth of the improved body. It is assumed that there is too much gap between the depth of the injection nozzle and the injection port, and the mud discharge cannot be performed smoothly. In this case, for example, the depth is improved in two steps, and the injection tube is changed in the first step. It is also necessary to carry out a multi-stage construction in which the improvement body is made longer, the injection pipe is shortened in the second stage, and the remaining upper improvement body is made.
That is, it is desirable that the length of the injection pipe can be adjusted so as to optimize the waste mud discharge promoting effect according to the lowest depth of formation of the improved body (or the depth of the top of the improved body) and the improved body growth.

It is a figure which shows the waste mud discharge | emission promotion apparatus which concerns on embodiment of this invention, FIG. 1 (A) is a front view, FIG.1 (B) is a top view, FIG.1 (C) is a top view which shows a spacer. It is explanatory drawing which shows the process of arrange | positioning the waste mud discharge | emission promotion apparatus of FIG. 1 in the boring hole of a construction ground. It is explanatory drawing which shows the process of FIG. 2 in detail. FIG. 3 is an explanatory diagram showing a step following the step shown in FIG. 2 and a step of injecting compressed air (fluid) from an injection port of an air tube (injection tube). It is explanatory drawing which shows the process of FIG. 4 in detail. FIGS. 6A and 6B are explanatory diagrams showing a ground-side end portion of the borehole, wherein FIG. 6A is an explanatory diagram when a guide pipe is disposed, and FIG. 6B is an explanatory diagram when a pit is provided. It is explanatory drawing which shows the other aspect of the injection port of the air pipe of a mud discharge promotion apparatus. It is explanatory drawing which shows the modification of embodiment of this invention, and shows the waste mud discharge | emission acceleration | stimulation apparatus which provided the injection port of the air pipe | tube in the different axial direction position in two steps. It is explanatory drawing of the ground improvement construction method which concerns on a prior art. In prior art, it is explanatory drawing which shows the condition where the mud discharge route was obstruct | occluded. It is explanatory drawing which shows FIG. 10 in detail.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
1 (A) and 1 (B), a waste mud discharge promoting device generally indicated by reference numeral 10 has four air pipes 1 (injection pipes), an air supply base 2 and spacers 3 (reinforcing plates). .
In the illustrated embodiment, the air tube 1 injects high-pressure compressed air (fluid) from the injection port 1A at the underground side end (the lower end in FIG. 1A). The ground-side end portion (the upper end in FIG. 1A) of the air tube 1 is connected to an air supply port 2A provided in the air supply base 2. Four air supply ports 2 </ b> A are provided corresponding to the air pipe 1.
The air tube 1 is shown here as a tube structure, but may be a tube satisfying a predetermined pressure resistance, and the material is basically made of steel metal, but may be hard rubber or the like.
Although not clearly shown, in the illustrated embodiment, the air tube 1 is fixed to the inner wall of the air supply base 2 in the vicinity of the connection with the air supply port 2A.

1 (A) and 1 (B), the air supply base 2 is formed in a thin cylindrical shape, and the upper portion of the air supply base 2 is located on the ground side when the mud discharge promoting device 10 is installed on the construction ground. It is configured like this.
The air supply base 2 is provided with four air supply ports 2A that protrude outward in the radial direction at equal intervals in the circumferential direction. 2 is fixed. The air supply port 2A is also located on the ground side when the mud discharge promoting device 10 is installed.
Compressed air is supplied to the mud discharge promoting device 10 from an unillustrated fluid supply source (for example, a compressor) on the ground side via the air supply port 2A.
In the illustrated embodiment, the fluid ejected from the ejection port 1A of the air tube 1 is high-pressure compressed air, but a gas other than the compressed air, a liquid such as water, and other fluids can be used.

By adjusting the length of the air pipe 1, the length in the axial direction (vertical direction when installed) of the mud discharge promoting device 10 can be adjusted. In the illustrated embodiment, the axial dimension of the mud discharge facilitating device 10 is such that the lower end of the air tube 1 is positioned above the improved top end KA (FIG. 2) of the improved body K (FIG. 2). Is set.
When the mud discharge promoting device 10 is installed, the air pipe 1 extends downward, that is, toward the ground side, and the outermost side of the air pipe 1 is a drilled bore hole H (see FIG. 2). Located near the inner wall.
In the embodiment shown in FIG. 2, the vicinity of the lower end of the air tube 1 is curved along the inner wall surface of the boring hole H and so as to rise obliquely upward, and its tip end is open. The injection port 1A is configured. Here, the injection port 1 </ b> A of the air tube 1 is set so that the injection direction of the fluid injected therefrom does not face the radial direction (normal direction) which is the outside in the axial radial direction of the solidified material injection rod 11. ing. That is, the radial direction is set to be a substantially tangential direction so that the hole wall of the boring hole H is not collapsed by the jet of fluid.
Further, the tip shape of the air tube 1 in the vicinity of the lower end of the air tube 1 and the axial direction of the solidified material injection rod 11 of the injection fluid flow at the injection port 1A are changed by the fluid to be injected as described below. The shapes of the air tube 1 and the injection port 1A differ depending on the direction of the injection fluid from the injection port 1A. There are also curved shapes as described above, and the air tube 1 including the injection port 1A is substantially the same. It is also linear.

In the illustrated embodiment, when the mud discharge promoting device 10 is installed, the air pipe 1 and the injection port 1A are disposed at positions such as along the inner wall surface of the boring hole H (see FIG. 2). If the air pipe 1 or the injection port 1A is disposed radially inward when the mud discharge promoting device 10 is installed, the mud discharge becomes a resistance to flow out to the ground side, and the smooth discharge of the mud is inhibited. This is because there is a risk of causing sludge accumulation and blockage.
When the mud discharge promotion device 10 is installed, the solidification material injection rod 11 axial direction in the fluid flow injection direction of the injection port 1A of the air pipe 1 is the ground improvement device 100 side when the fluid to be injected is liquid ( For example, it is set to face in the direction except the vertical underground direction)
When the fluid flow injection direction of the injection port 1A of the air pipe 1 is directed in the vertical underground direction, the injected fluid flow may prevent smooth discharge of the mud flow. On the other hand, when the fluid to be ejected is a gas, even if the fluid ejection direction of the ejection port 1A is directed to the vertical underground direction, the buoyancy to the ground side opposite to the vertical underground direction is exerted on the fluid flow that is a gas. Since it works, smooth discharge of mud can be promoted without hindering smooth flow of mud.
The cross-sectional area of the injection port 1 </ b> A of the air tube 1 is set smaller than the cross-sectional area in other portions of the air tube 1 by, for example, crushing. By setting the cross-sectional area of the injection port 1A of the air tube 1 to be small, the speed of the injected air can be increased, and foreign matter enters the air tube 1 from the injection port 1A when air is not injected. This is because it can be prevented.

1 (A) and 1 (B), the mud discharge promoting device 10 is provided with a spacer 3 (reinforcing plate) that maintains the interval between the four air tubes 1, and the spacer 3 is located in the vicinity of the central portion in the axial direction. It is arranged at two locations near the lower end. The spacer 3 is formed in a thin annular shape, and as shown in FIG. 1C, four air tube holding portions 3A are formed at equal intervals in the circumferential direction.
Although not shown, the air tube holding portion 3A is provided with a mechanism for preventing the spacer 3 from moving along the air tube 1 in the axial direction.
By arranging the spacer 3, the four air tubes 1 can maintain a mutual interval in the circumferential direction and the radial direction. Therefore, it is prevented that the air tube 1 moves in the circumferential direction and the radial direction, and the interval between the air tubes 1 is reduced. Thereby, the space | interval of the air pipes 1 becomes small, it is prevented that the outflow of waste mud to the ground side is prevented, and the possibility of retention and blockage of waste mud can be reduced.
In the mud discharge promoting apparatus 10, the spacer 3 can be omitted. The number of spacers 3 may be singular or may be three or more.
In FIG. 1, four air tubes 1 of the mud discharge promoting device 10 are provided, but the number of the air tubes 1 may be a plurality other than four according to the construction environment, or only one. It is also possible to make it. When determining the number of air tubes 1, the number of air tubes 1 is increased when the diameter of the solidifying material injection rod 11 is large, and the number of air tubes 1 is decreased when the diameter of the solidifying material injection rod 11 is small. It is also possible.

Next, with reference to mainly FIG. 2, FIG. 4, the aspect which promotes waste mud discharge | emission is demonstrated using the waste mud discharge | emission promotion apparatus 10 demonstrated with reference to FIG.
As shown in FIG. 4, in the ground improvement method of high-pressure jet agitation, the solidified material is injected from the solidified material injection rod 11 (double tube rod, multiple tube rod) inserted into the drilled bore hole H. Meanwhile, the solidifying material injection rod 11 is moved in the axial direction while being rotated or rotated (raised or lowered) to form an improved body (K: FIG. 4). During the construction of the improved body K, the mud containing solidified material, in-situ soil and foreign matter passes through the mud discharge route DR (see FIGS. 4 and 5) in the borehole H (see FIG. 4 and FIG. 5). It is discharged from the outlet 2B.
As shown in FIG. 2, the mud discharge facilitating device 10 is arranged in the region of the end portion on the ground side of the borehole H in order to promote the drainage of the mud to the ground side. Here, the mud discharge promoting device 10 is configured separately from the solidifying material injection rod 11.

In the step shown in FIG. 2, prior to injecting the solidified material from the solidified material injection rod 11, the mud discharge promoting device 10 is inserted from the ground side into the borehole H of the construction ground (see arrow E). It is arranged in the area of the ground side end. At that time, as described with reference to FIG. 1, the upper part of the air supply base 2 of the mud discharge promoting device 10 is disposed on the ground side. Then, the air supply port 2A of the air supply base 2 is connected to the fluid supply source (not shown) (for example, a compressor). The air supply base 2 is disposed on the ground side, and is not necessarily exposed to the ground, and may be disposed below the ground surface.
The four air pipes 1 connected to the air supply port 2A extend toward the underground side (lower side in FIG. 2), and the outermost side of the air pipe 1 is close to the inner wall surface of the boring hole H. Are arranged.
In the illustrated embodiment, four air tubes 1 are provided, but only two air tubes 1 are shown in FIG. Further, as described with reference to FIG. 1, the mud discharge promoting device 10 includes the spacer 3, but the illustration of the spacer 3 is omitted in FIG. 2.

In FIG. 2, the improved body K scheduled to be created is indicated by a one-dot chain line (virtual line), and the lower end portion of the air tube 1 is located above the improved top end KA of the improved body K. .
The vicinity of the lower end of the air tube 1 rises obliquely upward along the inner wall of the boring hole H, and the tip (opening) of the air tube 1 constitutes an injection port 1A.

Although not shown in FIG. 2, in the illustrated embodiment, a guide pipe 21 (see FIGS. 5 and 6A) is disposed at the ground side end of the borehole H. The guide pipe 21 extends in the ground direction from the upper end on the ground side of the boring hole H. The guide pipe 21 is, for example, below the lower end of the air tube 1 and from the improved top end KA of the improved body K. Also extends to an upper position P.
In the illustrated embodiment, the waste mud discharge promoting device 10 is disposed so as to extend inside the guide pipe 21 disposed at the end on the ground side in the boring hole H, and from the injection port 1A of the air tube 1. This fluid is ejected in the mud discharge route DR (FIGS. 4 and 5) in the guide pipe 21.
However, although not shown, it is also possible to configure the waste mud discharge path DR by positioning the lower end portion of the waste mud discharge promoting device 10 below the lower end portion (position P) of the guide pipe 21. .
The guide pipe 21 will be described later with reference to FIG.

In FIG. 3, the waste mud discharge promoting device 10 before being disposed in the boring hole H is shown. As described in FIG. 2, the mud discharge facilitating device 10 is inserted and disposed in the boring hole H as indicated by an arrow E.
After disposing the mud discharge promoting device 10 in the boring hole H, the solidified material is injected from the solidified material injection rod 11 indicated by the phantom line to create the improved body K (see FIG. 2).
Also in FIG. 3, illustration of the spacer 3 and the guide pipe 21 is abbreviate | omitted.

FIG. 4 shows a process of creating the improved body K by injecting a solidifying material. Reference numeral 100 denotes a ground improvement device that drives the solidifying material injection rod 11.
After the waste mud discharge promoting device 10 is disposed in the boring hole H, the solidifying material is injected from the solidifying material injection rod 11 inserted into the boring hole H (the jet of the solidifying material is indicated by a symbol J), The solidified material injection rod is moved in the axial direction while rotating or rotating (for example, as shown by the arrow A), and the improved body K is formed. At that time, the waste mud including the solidified material and the in-situ soil is discharged from the ground-side waste mud discharge port 2B via the boring hole H including the waste mud discharge route DR (FIGS. 4 and 5). .
In FIG. 5, the discharge of mud to the ground side is promoted by the waste mud discharge promoting device 10 arranged in the borehole H. When the discharged mud is discharged to the ground side, the fluid supply source (not shown) (for example, a compressor) is driven to supply the fluid to the discharged mud discharge promoting device 10 (arrow F0). The supplied fluid is injected from the injection port 1A of the air tube 1 into the boring hole H including the waste mud discharge route DR via the air supply port 2A and the air tube 1 (arrow F). Also in FIG. 5, illustration of the spacer 3 and the guide pipe 21 is abbreviate | omitted. And the lower end part of the guide pipe 21 is shown by the code | symbol P. FIG.
Here, the ejection of the fluid from the ejection port 1A is continuously or intermittently performed when the improved body is formed.
When the inventor experimented on a highly viscous ground, the solidification material injection rod 11 including the solidification material injection monitor has a diameter of 100 mm, a borehole H has a diameter of 200 mm, and 4 to 6 air pipes 1 to promote waste mud discharge. The fluid ejected from the ejection port 1A of the apparatus 10 uses compressed air, is ejected at 0.7 to 1.0 MPa at the original pressure of the compressor of the fluid supply apparatus, and the fluid ejection amount is 10 to 15 m ³ / min. It was possible to discharge the mud.

In FIG. 4, the mud discharged from the construction site of the improved body K (for example, mud containing foreign matter such as wood chips and clay blocks) rises to the ground side, and the boring hole H inner wall surface and the solidified material injection rod 11 outside. It flows through the mud discharge route DR constituted by a gap (annular space) with the side surface. And it discharges | emits on the ground from the mud discharge port 2B provided in the mud discharge promotion apparatus 10 (arrow B), and is sent to the said waste mud storage facility which is not shown in figure. A hose or the like is connected to the waste mud discharge port 2B and connected to a waste mud storage facility (a waste mud tank) (not shown) so that the waste mud pressurized by the fluid flow can be smoothly grounded. It is stored in the wastewater tank, and the wastewater treatment work is simplified.
When the mud flows through the mud discharge route DR toward the ground side, fluid is ejected from the ejection port 1A of the air pipe 1 (arrow F), and the ejected fluid rises to the ground side. In the illustrated embodiment, since the fluid is ejected obliquely upward, the ejected fluid rises by forming a spiral swirl flow.
The ejected fluid flow (fluid flow: the flow in which the ejected air rises) is added to the exhaust mud flow, so that the exhaust mud is entrained and the exhaust mud is expelled to the ground side. Therefore, even if foreign matter (for example, a piece of wood or a clay lump) is present in the improved body construction, the flow of discharging (raising) the mud is retained, and the foreign matter and the mud rise to the ground side. And the mud discharge route DR is prevented (suppressed) from being blocked.

As shown in FIG. 5, the injection port 1 </ b> A of the air pipe 1 of the waste mud discharge promoting device 10 is located above the position at the lower end position P of the guide pipe 21 (see FIG. 6) (an example of a region where the mud is easily blocked). If it is located, that is, if the injection port 1A of the air pipe 1 of the mud discharge promoting device 10 is disposed inside the guide pipe 21 (FIG. 6), the fluid injected from the air pipe 1 is discharged. Adding to the mud flow in the mud discharge route DR increases the moving speed of the mud, entrains clay lumps and foreign substances existing in the area where the mud tends to block, and promotes discharge to the ground side. Thus, the mud discharge route DR is prevented (suppressed) from being blocked.
In other words, according to the illustrated embodiment, regardless of the relative positional relationship between the injection port 1A of the air tube 1 and the area where the drainage mud easily closes, the area (for example, the lower end position P of the guide pipe 21) It is promoted that clay lumps and foreign matters move to the ground side in the place immediately below), and accumulation and blockage of waste mud are prevented.

  On the other hand, unlike the case shown in FIG. 5, the air pipe 1 of the mud discharge promoting device 10 is located below the position at the lower end position P of the guide pipe 21 (see FIG. 6) (an example of a region where the mud tends to block). When the ejection port 1A is positioned, the fluid ejected from the air pipe 1 passes through the region where the mud tends to be blocked and rises to the ground side. Lumps and foreign objects can be taken and discharged to the ground side more easily than in the above case. Therefore, the installation position of the guide pipe 21 and the fluid injection position from the injection port 1A do not limit the discharge of mud.

Although not shown in FIGS. 4 and 5, the waste mud discharge promoting device 10 is provided with spacers 3 (FIG. 1) that maintain the distance between the four air pipes 1. Therefore, it is prevented that the air pipe 1 moves inward in the radial direction, the interval between the air pipes 1 is reduced, and the outflow of the waste mud to the ground side is prevented. Is prevented.
Further, as described above with reference to FIG. 1, the cross-sectional area of the injection port 1 </ b> A of the air tube 1 is set smaller than the cross-sectional area of the air tube 1 other than the injection port 1 </ b> A. Therefore, it is possible to increase the ejection speed of the fluid ejected from the ejection port 1A and to prevent foreign matter from entering the air tube 1 through the ejection port 1A when the fluid is not ejected.

Here, for example, when high-pressure compressed air (air) or the like is injected from the side of the solidified material injection monitor of the solidified material injection rod 11, the compressed air or the like is generated from a position where the depth of the improved body K is deep. Is injected. In addition, by pulling up the solidifying material injection rod 11, compressed air or the like is injected from different depths. As a result, there is a possibility that compressed air or the like injected from the side of the solidifying material injection rod 11 may enter the radially outer region of the boring hole H.
When the injected compressed air or the like enters the radially outer region of the borehole H, the radially outer region of the borehole H rises on the ground due to the pressure of the compressed air (air), Inconveniences such as destruction of the pavement on the ground surface occur (see FIG. 10).
Moreover, if the depth of the air injection from the solidification material injection rod 11 is deep and air is discharged from below the groundwater level (underground side), the injected air entrains the groundwater and increases the amount of mud. There is an inconvenience that it ends up.

On the other hand, in the illustrated embodiment, the exhaust mud discharge promoting device 10 is configured separately from the solidifying material injection rod 11, and the lower end portion (injection position of compressed air or the like) of the exhaust mud discharge promoting device 10 is an improved body K. Since the axial dimension is set so as to be positioned above the improved top end KA, the fluid injected from the injection port 1A having a certain depth enters the region radially outward from the boring hole H. There is little fear of doing it. In addition, when the mud discharge promoting device 10 (the injection port 1A of the air pipe 1) is disposed inside the guide pipe 21 (FIG. 6), the fluid is radially outward from the bore hole H. There is no risk of entering the area.
Therefore, due to the pressure of the fluid that has entered the radially outer region of the boring hole H, the radially outer region of the boring hole H rises, causing inconveniences such as destroying the pavement on the ground surface. The possibilities are very small.

In FIG. 6 which shows the ground side edge part of a boring hole, the state by which the guide pipe 21 is arrange | positioned inside the boring hole H is shown by FIG. 6 (A). In FIG. 6A, in order to prevent the boring hole H from collapsing, the guide pipe 21 extends from the ground side end portion of the boring hole H toward the ground, and the outer peripheral surface of the guide pipe 21 is the boring. It arrange | positions so that the inner wall of the hole H may be adjoined.
3 and 4, as shown in FIG. 6A, the sludge discharge promoting device 10 is disposed inside the guide pipe 21 that is disposed inside the boring hole H. As described above with reference to FIG. 2, the guide pipe 21 extends to a position below the lower end portion of the mud discharge promoting device 10 and above the improved top end KA of the improved body K. ing.
By disposing the mud discharge promoting device 10 in the guide pipe 21, the high-pressure compressed air injected from the injection port 1 </ b> A of the air pipe 1 enters the radially outer region of the boring hole H as described above. The risk of doing so is reduced.

In FIG. 6 (B), a pit 20 (枡) is provided at the ground side end of the boring hole H. 3 and 4, the pit 20 is not provided. However, in FIGS. 3 and 4, the mud discharge promoting device 10 may be disposed in the borehole H with the pit 20 provided on the ground. good.
When the pit 20 is provided, the ground-side end portion of the boring hole H communicates with the bottom portion of the pit 20, and the mud discharge promoting device 10 is disposed in the boring hole H from the bottom portion of the pit 20.
By providing the pit 20 at the end on the ground side of the borehole H, the discharged mud can be temporarily stored in the pit 20 when the discharged mud is moved to a waste mud storage facility (not shown).

A shape other than that shown in FIG. 1 can also be applied to the shape of the injection port 1A (discharge port) of the air pipe 1 of the mud discharge promoting device 10. FIG. 7 shows another example of the shape of the ejection port 1 </ b> A (discharge port) of the air tube 1.
In FIG. 7A, a discharge port 1B is provided in the horizontal direction on the side surface in the vicinity of the lower end of the air tube 1 that extends downward (the underground side at the time of attachment).
In FIG. 7B, a slit-like discharge port 1C extending over a predetermined axial length on a side surface near the lower end of the air tube 1 extending downward (underground when attached, downward in FIG. 7). Is formed.
7A and 7B, only the small tubular 1B and the slit-shaped 1C are illustrated as examples of the shape of the injection port 1A of the air tube 1, and the injection direction and the injection interruption are illustrated. It does not specify the area.

In FIG. 7C, the air tube 1 is bent in the tangential direction and in the horizontal direction in the vicinity of the lower end, and a plurality of discharge ports 1D (5 in the illustrated example may be single) are formed on the side surface of the bent portion. Yes.
In FIG. 7D, the air pipe 1 is bent in the tangential direction and in the horizontal direction in the vicinity of the lower end, and a slit-like discharge port 1E extending over a predetermined length is formed on the side surface of the bent portion. .
As described above, FIGS. 7C and 7D illustrate the porous injection port 1D and the long slit injection port 1E as examples of the shape of the injection port 1A of the air tube 1. However, it does not specify the bending angle, the injection direction, or the injection cross-sectional area.
Here, as shown in FIG. 7 (E), the air tube 1 is constituted by a tubular material tapered toward one end (the lower end in FIG. 7 (E)), and the end on the narrow diameter side (FIG. In some cases, the opening at the lower end of 7 (E) constitutes the injection port 1F.

A modification of the embodiment of the present invention will be described with reference to FIG.
In FIG. 8, the discharge ports of the air pipe 1-1 of the mud discharge promoting device 10-1 are provided in two stages at different axial positions. That is, in FIG. 8, two air pipes 1-1 and 1-2 that extend downward (in the ground side at the time of attachment) and have different axial lengths are provided. The air tubes 1-1 or the air tubes 1-2 are arranged adjacent to each other in the circumferential direction of the air supply base 2, but the air tubes 1-1 and 1-2 are arranged around the circumference of the air supply base 2. You may arrange | position alternately in a direction.
The air tube 1-2 extends below the air tube 1-1, and the discharge port 1A-2 of the air tube 1-2 is positioned below the discharge port 1A-1 of the air tube 1-1. ing.
Although the waste mud discharge promoting apparatus 10-1 of the modified example of FIG. 8 has two each of the air tubes 1-1 and 1-2 having different lengths in the axial direction, the number may be other than that. . Moreover, the number of the air pipes 1-1 and the air pipes 1-2 may be different.

The mud discharge promoting apparatus 10-1 according to the modified example of FIG. 8 should set the axial length of the air pipe of the mud discharge promoting apparatus to be long, for example, when the depth of the region where the improved body K is created is deep. It is effective in the case.
For example, the discharge port 1A-1 of the air pipe 1-1 of the mud discharge promoting device 10-1 is positioned above a region where the mud is easily blocked (for example, a region immediately below the position where the guide pipe 21 is disposed). The discharge port 1A-2 of the air pipe 1-2 can be positioned above the improved top end KA of the improved body K below the region where the mud is likely to close.
Other configurations and operational effects in the modified example of FIG. 8 are the same as those of the embodiment of FIGS.

It should be noted that the illustrated embodiment is merely an example, and is not a description to limit the technical scope of the present invention.
For example, in the illustrated embodiment, the length of the air pipe 1 of the mud discharge promoting device 10 is constant, but the length of the air pipe is made variable (for example, by providing a screw mechanism on the air pipe). Is possible.
Moreover, in embodiment of illustration, although the fluid is injected from the four air pipes 1 of the mud discharge | emission promotion apparatus 10, it is a liquid from some air pipes 1 (for example, two air pipes 1). It is possible to inject water and inject compressed air, which is a gas, from the other air pipes 1 (the remaining two air pipes 1).
Further, in the illustrated embodiment, fluid is always ejected from the air pipe 1 of the mud discharge promoting device 10 to prevent the mud discharge route DR from being blocked. Only when the mud discharge route DR is blocked, it is also possible to configure so as to eliminate the blockage by ejecting fluid.
In addition, in order to prevent foreign matter from entering the air tube 1 through the injection port 1A, a check valve can be provided in the region of the air tube 1 near the injection port 1A.

1 ... Air tube 1A ... Injection port (discharge port)
2 ... Air supply base 2A ... Air supply port 2B ... Waste mud discharge port 3 ... Spacer 10 ... Waste mud discharge promoting device 11 ... Solidification material injection rod (double tube rod, Multiple tube rod)
20 ... Pit 21 ... Guide pipe DR ... Mud discharge route H ... Boring hole K ... Improved body KA ... Improved top

Claims (11)

When solidifying material is injected from the solidified material injection rod inserted into the drilled borehole, the solidified material is solidified when the solidified material injection rod is moved in the axial direction while rotating or rotating to create an improved body. In the waste mud discharge promoting device arranged in the region of the ground side end portion of the boring hole in order to facilitate the flow of the waste mud from which the waste mud containing the material and the in-situ soil is discharged to the ground side,
It is configured separately from the solidifying material injection rod,
An air tube having an ejection port for ejecting fluid at the tip, and a fluid supply port communicating with a fluid supply source;
The axial dimension is set so that the lower end is located above the improved top,
A waste mud discharge promoting device, wherein a fluid is jetted into a waste mud discharge path from the jet port of the air pipe to form a fluid flow, and the fluid flow is added to the waste mud flow.   The exhaust mud discharge promoting device according to claim 1, wherein, in the fluid flow injection direction, the radial direction of the solidifying material injection rod axis is a substantially tangential direction around the solidifying material injection rod.   The solid waste injection rod axial direction in the fluid flow injection direction is the ground improvement device side when the fluid to be injected is liquid.   The waste mud discharge promoting apparatus according to any one of claims 1 to 3, wherein a plurality of the air pipes are provided, and a spacer is provided to maintain a distance between the plurality of air pipes.   The waste mud discharge promoting device according to any one of claims 1 to 4, wherein the number of the air pipes is arranged by increasing or decreasing the number according to the diameter of the solidifying material injection rod.   The exhaust mud discharge promoting device according to any one of claims 1 to 5, wherein a cross-sectional area of the injection port of the air tube is smaller than a cross-sectional area of the air tube other than the injection port.   The exhaust mud discharge promoting device according to any one of claims 1 to 6, wherein the air pipe has a check valve function for preventing the exhaust mud from flowing back into the flow path of the air pipe.   The length of the air pipe is set based on the bottom end depth of the improved body and the improved body growth, and can be adjusted to a length effective for promoting the discharge of mud according to the depth of spraying the solidified material. The waste mud discharge promoting apparatus according to any one of 1 to 7. When solidifying material is injected from the solidified material injection rod inserted into the drilled borehole, the solidified material is solidified when the solidified material injection rod is moved in the axial direction while rotating or rotating to create an improved body. In the waste mud discharge promotion method that makes it easy for the sludge flow that drains the sludge containing the wood and the original soil to flow to the ground side,
The solidified material injection rod is configured separately from the air pipe having an injection port for injecting fluid at the tip and a fluid supply port communicating with the fluid supply source, and the lower end portion is positioned above the improved top end. The axial dimension is set to
A waste mud discharge facilitating device for injecting a fluid from the injection port of the air pipe into a waste mud discharge path to form a fluid flow and adding the fluid flow to the waste mud flow is provided in the region of the ground side end of the boring hole. Place and
A ground improvement characterized in that when drainage mud is discharged to the ground side, fluid is ejected from the jetting port through the fluid supply source, the fluid supply port, and the air pipe to promote drainage of the mud. Construction method. Disposed in the region of the ground side end portion of the boring hole is a sludge discharge promoting device configured such that the radial direction of the solidifying material injection rod axis is substantially tangential around the solidifying material injection rod in the fluid flow injection direction. And
The ground improvement method according to claim 9, wherein when drainage mud is discharged to the ground side, fluid is ejected from the jet port through the fluid supply source, the fluid supply port, and the air pipe to promote drainage of the mud. . In the fluid flow injection direction, the solidified material injection rod axial direction is configured such that when the fluid to be injected is a liquid, the ground mud discharge promoting device is configured to be on the ground improvement device side. Placed in the area
The discharge of mud is promoted by injecting fluid from the injection port via the fluid supply source, the fluid supply port, and the air pipe when the discharged mud is discharged to the ground side. The ground improvement construction method.

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