JPH079089B2 - Injection equipment for large diameter ground improvement - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is to insert a pipe into a hole previously drilled in the ground and to supply high-pressure liquid from the first and second nozzles of an injection device provided at the tip of the pipe. And the ground improvement injection liquid is injected, the pipe is pulled up from the ground, the ground is cut, the ground improvement injection liquid is injected, and the ground columnar solid is formed to improve the ground improvement injection device. Regarding

[Prior Art] Various such devices are known (for example, Japanese Patent Publication No. 56-26730, Japanese Patent Publication No. 56-731, and Japanese Patent Publication No.
57-38728, Japanese Patent Publication No. 57-55849 and Japanese Patent Publication 58
No. 30444, etc.), when forming a cylindrical ground improvement portion, the pipe was pulled up while rotating, and when forming a vertical flat plate ground improvement portion, the pipe was pulled up without rotating.

In these devices, the number of nozzles for injecting high-pressure liquid is usually one, as shown in FIG. 5, to reduce the outer diameter of the injection device 1. It was bent at a right angle at the entrance. for that reason,
The jet fluid was in a turbulent state in the straight portion 4 and passed through the nozzle 2 as it was, so the jet stream J did not become a theoretical stream and the cutting ability was low.

On the other hand, in order to improve the cutting ability, the injection pressure and the flow rate are increased and the cutting time is lengthened in a fine range.

In order to reduce the turbulence of the jet flow J, it is required to make the laminar flow without generating turbulence in the straight line portion 4. This is due to the flow rate and the pipe diameter d of the straight line portion 4 shown in FIG. It is determined by the length 1 and, as is well known, 1 / d = 100 to 150 is a suitable value for complete laminar flow.

On the other hand, since there is a restriction on the pipe diameter of the double pipe of the pipeline that transports the high-pressure liquid and the ground improvement liquid (the triple pipe in the case of the three liquids of high-low pressure liquid and ground improvement injection liquid), the above-mentioned suitable In order to satisfy the value, it is necessary to make the pipe diameter d of the straight portion 4 as small as possible. Further, the upper limit of the preferable flow velocity for laminar flow is set to 10 m / sec, and therefore the flow amount becomes small. However, when the flow rate decreases, the flight distance of the jet stream J, that is, the cutting ability decreases.

On the other hand, a large cutting capacity is required to form a large-diameter columnar solidified body. According to the research conducted by the present inventor, the discharge amount is more effective than the discharge pressure in improving the cutting ability,
It has been confirmed that 0 liter or more is preferable.

A technique of arranging a hardening agent nozzle in a ring shape so as to wrap air around an air nozzle is disclosed in JP-A-53-46109. However, such a known technique uses cavitation of air to increase the impact force, and does not discharge a large amount of high-pressure liquid in order to obtain a large-diameter solidified body.

Further, Japanese Utility Model Laid-Open No. 55-24367 discloses a technique in which a lip stopper is provided outside the high-pressure injection nozzle, and a small hole in the lip stopper normally closes the lip valve.
After all, a large amount of high-pressure liquid cannot be discharged.

[Problem to be Solved by the Invention] Therefore, an object of the present invention is to provide a large-diameter ground improvement injection device capable of discharging a large amount of high-pressure liquid and thereby obtaining a large-diameter underground solidified body. It is in.

[Means for Solving the Problems] According to the present invention, the pipe is inserted into a hole previously drilled in the ground, and the first and second injection devices are provided at the tip of the pipe.
A high-pressure liquid and a ground improvement injection liquid are jetted from the respective nozzles, the pipe is pulled up from the ground, the ground is cut, the ground improvement injection liquid is injected, and a ground columnar solid is formed to improve the ground. In the improvement injection device, the first nozzle is composed of a plurality of nozzles arranged in a ring shape, a third air nozzle is provided on the outer periphery of the first nozzle arranged in a ring shape, and the third nozzle is arranged in the ring shape. The second nozzle is arranged at the center of the formed first nozzle.

[Operation] In the large-diameter ground improvement device configured as described above, a plurality of nozzles arranged in a ring shape have a group pile effect, that is, a plurality of piles driven in a ring shape interact with each other. Similar to the effect of a pile that has a cross section of a virtual wheel that is continuous at the position where it is driven in, a diameter equivalent to a virtual wheel that is continuous at the position where it is arranged is created by the interaction of the jet flows from each nozzle. Performs a large-diameter cutting action like the nozzle of.

In addition, the discharge amount of one nozzle is, for example, about 50
%, The flow velocity decreases correspondingly, the jet flow approaches the theoretical flow, and the flight distance increases.

Therefore, the cutting ability and the cutting speed are improved as compared with the case where the total discharge amount of the first nozzle is ejected from one nozzle.

Moreover, the 2nd nozzle provided in the center of the 1st nozzle improves mixing and stirring of the ground improvement injection liquid and cutting soil.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the injection device 10 of the present invention in which a crane 20 is installed in a guide hole H.
Shows the state of being suspended.

A triple pipe 16 and a triple swivel 17 are sequentially connected to the upper portion of the injection device 10, and a pipe 18 for injecting high-pressure water, compressed air and cement milk is connected to the triple swivel 17, and the inside of the triple pipe 16 is separated. It flows and is guided to the injection device 10. The triple pipe 16 is rotatably supported by a support device 19 and is vertically moved by a crane 20.

2 to 4, on the side of the injection device 10,
A plurality of (five in the illustrated example) first high-pressure water nozzles 11a to 11e (referred to as 11 in the following description), which are the first nozzles, are arranged in a ring shape, that is, at each apex of a regular pentagon. It is located in. A straight line portion 12a of the high-pressure water pipe 12 which is bent at a right angle is connected to an inlet portion of the first nozzle 11. Then, the total discharge amount of the high-pressure water nozzle 11 is set to about 300 liters per minute, and therefore the discharge amount of one nozzle is set to about 50% of the conventional value.

Further, an air nozzle 13 is provided so as to surround the high-pressure water nozzle 11 and to be concentric with a virtual wheel C that is continuous with the injection port of the nozzle 11, and this air nozzle 13 is connected to an air pipeline 14. An injection liquid nozzle (not shown), which is a second nozzle, is connected to the injection pipe line 15. The injection liquid nozzle is provided at the center of the high-pressure water nozzle 11.

Therefore, when the high-pressure water is jetted from the high-pressure water nozzle through the high-pressure water pipe 12, the jet flow J jetted out has a discharge amount, that is, a flow velocity that is approximately half that of the conventional jet flow.

Further, the five jet streams J of the high-pressure water nozzle 11 arranged in a ring shape exert the cutting ability of each jet stream, and
Similar to the above-mentioned group pile effect by interacting with each other, the cutting action is performed as a jet flow from a nozzle having an imaginary ring C as the diameter, and a large amount of high pressure water of 300 liters per minute is used to make the cutting force higher than before. Demonstrates a large cutting ability and forms a large diameter columnar solidified body.

Further, the annular air jet stream jetted from the air nozzle 13 works to envelop the jet stream J of the high-pressure water to extend the flight distance, thereby helping to improve the cutting ability.

[Effects of the Invention] As described above, the present invention has the following excellent effects.

(I) The jet flow from the high-pressure water nozzles arranged in a ring shape is close to the theoretical flow and interacts with each other to greatly improve the cutting ability and cutting speed with the same effect as the group pile effect. it can.

(Ii) A large amount (300 liters per minute) of high-pressure water can be sprayed at the same time, improving the cutting ability.

(Iii) Since the second nozzle is provided in the center of the first nozzle, the mixing and stirring of the earth and sand and the ground improvement injection liquid are improved,
The quality of the solid can be improved.

(Iv) The flying distance of the high-pressure liquid is extended by the third air nozzle on the outer circumference of the first nozzle.

(V) Therefore, a large-diameter solidified body can be efficiently formed, and a large-diameter ground can be improved.

[Brief description of drawings]

FIG. 1 is a side view showing an injection device suspended by a crane, FIG. 2 is a front view showing an essential part of an embodiment of the present invention, and FIGS. 3 and 4 are AA of FIG. FIG. 5 is a vertical sectional view showing a main part of a conventional device, and FIG. 6 is a drawing for explaining a conduit and a nozzle. C ... Virtual wheel, J ... High-pressure water jet stream, 10 ... Injection device, 11a to 11e ... High-pressure water nozzle, 12 ... High-pressure water conduit, 15
...... Injection fluid line

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Hiroaki Kubo, 1-6-4 Moto-Akasaka, Minato-ku, Tokyo Within Chemical Grout Co., Ltd. (72) 1-6-4 Moto-Akasaka, Minato-ku, Tokyo Within Chemical Grout Co., Ltd. (56) Reference JP-A-53-46109 (JP, A) JP-A-59-217828 (JP, A) Practical application Sho-55-24367 (JP, U)

Claims (1)

[Claims] 1. A pipe is inserted into a hole drilled in the ground in advance, and a high pressure liquid and a ground improvement injection liquid are injected from first and second nozzles of an injection device provided at the tip thereof, respectively.
In a ground improvement injection device for pulling up a pipe from the ground, cutting the ground, and injecting a ground improvement injection liquid to form a columnar solidified body to improve the ground, the first nozzle is arranged in a ring shape. A plurality of nozzles arranged in a ring shape, a third air nozzle is provided on the outer periphery of the first nozzle arranged in a ring shape, and the second nozzle is arranged in the center of the first nozzle arranged in a ring shape. An injection device for large-diameter ground improvement characterized by the above.