JP2946110B2 - Soil improvement method using shield machine for soil improvement - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for injecting a chemical solution such as a soil improving agent into soil excavated by a shield machine to improve soil quality, and more particularly to a method for injecting a soil material. The present invention relates to a method for injecting a chemical solution during a rapid improvement operation that is rapidly improved.

(Prior art) if groundwater pressure of 1.0 kg / cm ² before and after the conventional earth pressure system shield machine is drilling a working face which acts to increase the water cut of the soil by adding a soil improvement agent to the excavated earth and sand, and When discharging the earth and sand by the screw conveyor, a plug made of earth and sand is formed in the casing of the screw conveyor, and the plug holds the earth pressure against the groundwater pressure in the chamber by this plug. It prevents earth and sand from being taken into the chamber more than necessary.

Conventionally, when soil is carried out from the chamber by a screw conveyor, soil improvement agents are continuously injected into the soil to improve the soil quality. The rapid improvement operation is performed by increasing the injection amount of the chemical.

In the conventional rapid improvement operation, the screw is rotated forward and backward by closing the gate on the discharge port side of the screw conveyor so that the chemical solution is quickly mixed into the earth and sand.

(Problems to be Solved by the Invention) However, in this method, the earth and sand in the casing move forward and backward each time the screw is rotated forward and backward, so that the earth pressure in the chamber fluctuates and the balance with the face becomes unstable. In addition, there has been a problem that the plug formed in the casing is broken and the earth pressure in the chamber cannot be maintained.

In addition, since the chemical is injected from one location, the addition amount of the chemical becomes uneven depending on the location in the casing, and there has been a problem that the earth and sand temporarily improved after the improvement is discharged.

In addition, when discharging earth and sand by a screw conveyor, a plurality of injection valves are appropriately opened and closed in the screw conveyor casing to inject a chemical solution into the earth and sand. Japanese Utility Model Application No. 55-100952 (Jpn. -26497).

That is, the above-mentioned is a screw conveyor with a shaft, in which a blade at a middle portion of the screw shaft is removed in order to provide a transfer amount reducing portion, and a blade or a rod having a reduced transfer area is provided instead of the screw blade, and A plurality of injection ports are provided in an intermediate portion of the casing.

In this way, even if blades with a reduced conveying area are provided in place of screw blades and the additive is injected due to different soil quality or spring water, excavated earth and sand will be ejected from the outlet of the screw conveyor in an unimproved state. Then, when closing the gate to stop the discharge of excavated sediment and improving the soil quality of excavated sediment in the casing, the excavated sediment stops moving toward the discharge port, and even if the screw shaft is rotated, the screw shaft and excavated sediment are removed. Are co-rotating, and even when the additive is injected, the additive penetrates only between the inner surface of the casing and the surface of the excavated earth and sand, so that the blade has little effect of stirring the additive and the excavated earth and sand.

Furthermore, since the gate is closed, even when the screw shaft is rotated, the co-rotation with the excavated soil causes the additive to inject the surface of the concentric cylindrical shape of the excavated earth and sand in a narrow range in the longitudinal direction,
Since there is no stirring by the blades, there is no stirring effect between the chemical and the earth and sand, and therefore there is almost no effect of improving the soil quality.

Furthermore, when a rod is provided on the screw shaft instead of the screw blade, the area where the rod is provided has no transfer capacity, so even if the gate is closed and the chemical is injected, the soil is improved in the area where the rod is provided. There was a problem that the screw conveyor was clogged with the rods and the screw conveyor was clogged even when the gate was opened.

SUMMARY OF THE INVENTION The present invention has been made for the purpose of improving the above-mentioned disadvantages, and there is a need to provide a method of injecting a chemical solution during a rapid improvement operation that enables rapid improvement of soil quality without rotating a screw of a screw conveyor forward and backward. .

(Means for Solving the Problems) The present invention has been made to achieve the above-mentioned object, and the earth and sand excavated by a cutter head attached to a front portion of a shield main body and taken into the chamber is supplied to the chamber by a screw conveyor. When carried out from the inside, in the soil improvement method using a shield excavator for injecting a chemical solution into the earth and sand through a chemical solution injection pipe provided in the casing of the screw conveyor to improve the soil quality, poor soil improvement occurred. In this case, the gate provided at the discharge port of the ribbon screw conveyor having no shaft is closed, the injection valve provided at the injection pipe connected to the casing of the ribbon screw conveyor is opened and closed, and the ribbon staying in the casing is Injecting a chemical solution in the earth and sand that is being rotated and stirred by a screw conveyor to improve soil quality It is.

(Effects) Therefore, when the excavated earth and sand is moved to the rear discharge port by the ribbon screw in the casing, if the excavated earth and sand is in an unimproved state, the gate is closed, the excavated earth and sand is stopped, and the screw is moved by rotation of the screw. The excavated sediment moves in the hollow hole around each blade of the ribbon screw while being compacted as approaching the gate, and the excavated sediment flows while being stirred.

That is, even if the gate is closed, when the ribbon screw is rotated, the excavated earth and sand has a greater degree of freedom to move in the casing due to the hollow holes around each blade of the ribbon screw.

As a result, the excavated earth moves backward by the ribbon screw blades and is compacted, and the hollow hole around each blade of the ribbon screw moves again. Convection while being done.

Since the excavated soil repeats such a movement process, if a chemical is injected from the inlet of the ribbon screw conveyor,
The excavated earth and sand and the chemical can be uniformly stirred and mixed.

There is no need to rotate the ribbon screw forward and reverse to mix and mix the excavated earth and chemicals.Therefore, the face rotation and earth pressure in the chamber do not become unstable due to the reversal, and the excavated earth and sand are placed in the casing near the discharge port. The soil quality can be rapidly improved without breaking the water stop plug formed by the above.

In addition, by injecting chemicals from multiple inlets, the excavated earth and chemicals are evenly mixed over a wider area of the casing in addition to the convection of the excavated earth and sand. Plug zones can be formed.

In addition, when excavated soil with improved soil quality is continuously discharged from the discharge port, by selecting an injection port at an appropriate position from a plurality of injection ports, it is possible to adjust the reaction time of the chemical even with different soil types. Can be applied to a wide range of soils.

(Embodiment) One embodiment of the present invention will be described in detail with reference to FIGS.

FIG. 1 shows an earth-pressure shield excavator, which has a shield jack 2 in a shield main body 1 for propelling the same into the ground and a cutter head motor 3 at the front of the shield main body 1. A cutter head 4 is provided.

A number of cutters 4a protrude from the front surface of the cutter head 4. Sediment excavated by these cutters 4a is taken into the chamber 1a from a sediment intake port (not shown), and is then removed from the chamber 1a by the ribbon screw conveyor 5. It is carried out, and further carried out backward by an unloading device (not shown).

The front end of the ribbon screw conveyor 5 is the chamber 1a.
The casing 5a includes a casing 5a projecting inward, and a screw 5b rotatably accommodated in the casing 5a.
5b is driven by a motor 6 installed on the rear end side of the casing 5a.

A discharge port 5c opened at the rear end of the casing 5a.
Is provided with an openable and closable gate 5d.

On the other hand, reference numeral 7 in the figure denotes a chemical solution tank containing a chemical solution such as a soil conditioner. The chemical solution in the tank 7 is supplied by a chemical solution pump 8 through a chemical solution supply pipe 9 to the ribbon screw conveyor 5.
Into the casing 5a.

A plurality of injection pipes 9 ₁ , 9 ₂ , 9 ₃ ...
… Are provided with injection valves 10 ₁ , 10 ₂ , 10 ₃ …
The tips of the injection pipes 9 ₁ , 9 ₂ , 9 ₃ ... Are connected to the casing 5a at substantially equal intervals from the tip side of the casing 5a.

Next, a method of injecting a chemical solution in the shield machine described above will be described. The earth and sand excavated by the cutter head 4 in accordance with the propulsion of the shield main body 1 is taken into the chamber 1a, and then is fed into the chamber 1a by the ribbon screw conveyor 5. From the casing, but during normal operation the casing
Injection pipe 9 ₁ connected to 5a, 9 and ₂ only injection valve 10 ₁ of the injection pipe 9 ₁ located foremost among ...... opened as shown in Figure 2.

This chemical sent from a chemical solution pump 8 is injected from the injection pipe 9 ₁ in the casing 5a, a screw 5a
Is mixed with the earth and sand being conveyed, thereby improving the soil quality.

On the other hand, when the soil quality cannot be sufficiently improved even if the soil quality is improved by the above-described method, a rapid improvement operation is started.

Rapid improvement operation, closes the gate 5d of dumping port 5c, foremost to open and close the injection valve 10 ₁ of the injection pipe 9 ₁ provided on the next sequentially backward as shown in FIG. 3 in this state Injection valve 10 ₂ ,
10 ₃ Open and close in order.

As a result, the chemical sent from the chemical pump 8 is
Is first injected from the injection pipe 9 ₁ in the casing 5a, it is mixed in subsequent injection pipe 9 _2, 9 ₃ are injected ...... sequentially in a casing 5a from sediment, so rapid improvement of soil are carried out.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a shield machine used in the method of the present invention, FIG. 2 is an explanatory view showing a chemical liquid injection method during normal operation, and FIG. 3 is a chemical liquid injection method during rapid completion operation. FIG. DESCRIPTION OF SYMBOLS 1 ... Shield body, 1a ... Chamber 4 ... Cutter head, 5 ... Ribbon screw conveyor 5a ... Casing, 5b ... Screw 5c ... Discharge port, 5d ... Gate 9 ₁ and 9 ₂ ... Injection pipe, 10 ₁ and 10 ₂ ... Injection valve

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References Practical application Microfilm (JP, U) “Photographing the contents of the specification and drawings attached to the application of Japanese Patent Application No. 55-100952 (Japanese Utility Model Application No. 57-26497) McGraw-Hill Dictionary of Scientific and Technical Terms ”, 1st edition (54-3-20), Nikkan Kogyo Shimbun, 1486 pages

Claims (1)

(57) [Claims] When a cutter head attached to a front part of a shield main body excavates and takes in earth and sand taken into a chamber from a chamber by a screw conveyor, earth and sand pass through a chemical solution injection pipe provided in a casing of the screw conveyor. In the soil improvement method using a shield excavator to improve the soil quality by injecting a chemical solution into the inside, if the soil improvement failure occurs, the gate provided at the discharge port of the ribbon screw conveyor without shaft is closed Then, by opening and closing an injection valve provided in an injection pipe connected to the casing of the ribbon screw conveyor, a chemical solution is injected into earth and sand that is retained in the casing and is rotated and stirred by the ribbon screw conveyor, and soil is removed. A soil improvement method using a shield machine designed to improve.