JP2002180450A - Ground freezing construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems in a conventional ground freezing method, wherein liquid nitrogen, calcium chloride, ammonia, hydrocarbon and fleon refrigerants are used as a refrigerant and a cooling pipe for circulating the refrigerant is additionally provided and these refrigerants influence human beings and environment in some way with the possibility of having large influence on workers and inhabitants in the surroundings by the damage or the like of the cooling pipe, an equipment cost for the additional installation and removal of the cooling pipe is high and freezing cannot be attained simultaneously with excavation in the case a large quantity of moisture does not exist around the cooling pipe since heat resistance becomes high due to the formation of cavities between the cooling pipe and the ground. SOLUTION: At least two communicating excavated holes are provided, and low- temperature air is blown in to either one of the excavated holes. In the case of a single hole, low-temperature air is fed through an air feed pipe inserted in the excavated hole, and the low-temperature air is exhausted through a clearance between the excavated hole and the air feed pipe. The wall surface of the excavated hole is frozen simultaneously with excavation by feeding the low-temperature air into a space formed between an excavating drill and the excavated hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD OF THE INVENTION

[0002]

[Prior art]

[0003] In the conventional ground freezing method, a refrigerant pipe is inserted into an excavation hole provided in the ground so as to be in close contact with the wall surface, and the cooled refrigerant is fed into the refrigerant pipe to cool the wall surface of the excavation hole. The refrigerant pipe is provided with a refrigerant sending channel and a refrigerant returning channel. This ground freezing method is hereinafter referred to as a first method.

A method has also been proposed in which a liquefied refrigerant, nitrogen gas, or the like is directly blown onto a wall of an excavation such as a tunnel. This ground freezing method is hereinafter referred to as a second method.

[Problems to be solved by the invention]

In the first method, it is necessary to provide a refrigerant sending flow path and a refrigerant returning flow path in a refrigerant pipe inserted into the ground, and the refrigerant pipe is complicated and expensive. Yes, a space is easily created between the refrigerant pipe and the ground, and the thermal resistance between the ground and the refrigerant pipe increases.After the water contained in the ground is frozen, the water in the refrigerant pipe and the ground freezes and the ground and the refrigerant pipe The frozen ground is thawed by feeding hot water or high-temperature refrigerant to the refrigerant pipe, which is difficult to withdraw because it is in a fixed state, but the hot water or refrigerant evaporates in the refrigerant pipe and blocks the pipe. There is a limit to high temperature,
If the refrigerant pipe is broken, there is a drawback that the refrigerant leaks out, causing danger to the human body and the environment.

In the second method, when a low-temperature refrigerant or liquefied gas is directly blown on a wall surface in a gallery, the refrigerant or liquefied gas is gasified and filled in the gallery, thereby avoiding danger to the human body and the environment. For this purpose, there are drawbacks such as the necessity of a ventilation device in the tunnel, the necessity of disposal thereof, and the great effect on the environment.

[Means for Solving the Problems]

[0007] Air which is harmless to the human body and the environment is used as a refrigerant.

[0008] The borehole is used as a refrigerant passage and a cooling pipe.

A water pump is used to control the amount of water in the ground.

[0010] At least two drill holes communicate with each other to form a cooling air passage.

The outer peripheral space formed by the drill is used as a cooling passage, and the drain passage inside the drill is also used as an exhaust passage.

[0012] If necessary, a pipe for draining or supplying water is inserted into the borehole to drain or supply water.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 shows the configuration of the first embodiment. Example 1
Communicates with the excavation hole (120) excavated in the ground (100) in the vicinity of the tip of the excavation hole (130).
0), low-temperature air is blown from the inlet of the air inlet nozzle (231) to the inner surface (121) of the borehole and the inner surface (13) of the borehole.
1) is frozen. Cryogenic air is generated in a cryogenic air generator (200), regulated by an air valve (220), and passed through a cryogenic air pipe (210) to an air inlet pipe (23).
0). The air inlet pipe (230) is fixed to the ground (100) with a flange (232) and a fixture (234), and the low-temperature air is sealed with a sealing material (233).
The air flow direction (240) indicated by the dashed arrow indicates the direction of the flow of the cold air.

FIG. 2 shows the configuration of the second embodiment. Example 2
Shows an example of the configuration of a drilled hole. (A) in the figure
Is provided with a communication hole (140) intersecting both the excavation hole (120) and the excavation hole (130), and (B) is provided with a plurality of excavation holes shown in the first embodiment. . There are many arrangements of the excavation holes, and the flow of the low-temperature air may be in a series or in parallel, and the arrangement may be a combination of staggered or cross-cut.

FIG. 3 shows the configuration of the third embodiment. Example 3
Is for freezing a single drilling hole (120), in which an air inlet pipe (230) is inserted near the tip of the drilling hole (120) to blow out low-temperature air, and After cooling, the inner surface (121) of the drill hole is cooled and the drill hole (120) is cooled.
The used low-temperature air is discharged from the inlet.

FIG. 4 shows the configuration of the fourth embodiment. Example 4
Is a case in which a large amount of water accumulates or flows into the borehole (120) in the third embodiment, and the pump (34) passes through the drainage pipe (310) and the water guide pipe (320).
0) to drain the water, and to efficiently freeze the inner wall (121) of the drilling pipe.

FIG. 5 shows the structure of the fifth embodiment. In the third embodiment, when there is a crack (101) or the like at the bottom of the excavation hole (120) and water runs out and runs short, the water surface (300) is held at an appropriate position by water injection from the outside and frozen. This is to ensure the necessary water content. Typical drilling requires an appropriate amount of water at the tip of the drill for cooling and lubrication.

FIG. 6 shows the structure of the sixth embodiment. Example 6
Performs freezing of the inner surface of the drilling hole (121) at the same time as drilling. A closed room (250) for low-temperature air is provided on the outer periphery of the drilling support tube (400) for drilling, and the drill support tube (400) is provided.
Outer space (440) created between the borehole (120)
Through the borehole (120) to freeze the cooling hole inner wall (121). The low-temperature air reaching the bottom of the drilling hole (120) is used for drilling a drill bit (421).
Flows to the inner space (430) through the gap between
Released to the atmosphere. In an inner space (430) between the drill support pipe (400) and the pillar (150) cut out by drilling, cutting powder and the like is pushed up by the buoyancy of low-temperature air in water. Cold air acts as a bubble pump.

FIG. 7 shows the structure of the seventh embodiment. In the sixth embodiment, an upper air hole (411) and a lower air hole (424) are provided in the drill base (410) and the drill blade (420) to increase the flow rate of low-temperature air. FIG. 8 shows an example of the shape of the upper air hole (411) for improving the air flow.

【The invention's effect】

Refrigeration using only air is safe for human beings and the environment. Not only does it require a special ventilator even when used inside a tunnel where humans work, but also releases cold air inside. If so, it also serves as a ventilator.

Even if the cooling pipe is damaged and the refrigerant leaks, there is no harm to humans and the environment.

The conventional cooling pipe is unnecessary, and the cost for installation and removal is small.

Since the low-temperature air is directly blown into the excavation hole provided in the ground, the heat resistance is small and the cooling efficiency is high. High heat transfer rate due to high cooling air flow rate. From -20 to-
Since the temperature of the low-temperature air can be freely adjusted to 160 ° C., the freezing speed can be easily adjusted.

Since a special cooling pipe is not required, the shape of the excavation hole can be freely formed.

The excavation hole can be frozen at the same time as the excavation.
By co-freezing, it is also possible to supply an appropriate amount of water to retain the water required for the drill.

[0026]

[Brief description of the drawings]

FIG. 1 Refrigeration method by direct insertion of low-temperature air into a V-shaped drill hole

FIG. 2 U-shaped and W-shaped drill holes

FIG. 3 Single hole air refrigeration method

FIG. 4 Air refrigeration method with a single drilling hole combined with drainage

Fig. 5 Air refrigeration method with water supply and crack closure single borehole

FIG. 6: Simultaneous excavation single air hole air refrigeration method

FIG. 7: air holes

FIG. 8: Air hole shape

[0027]

[Explanation of symbols]

 (100) Ground (101) Crack (110) Ground surface (120) Drilled hole (121) Drilled hole inner wall (130) Drilled hole (131) Drilled hole inner wall (140) Communication hole (150) Stone pillar (200) Low-temperature air generation Device (210) Cold air pipe (220) Air valve (230) Air inlet pipe (231) Air inlet nozzle (232) Air inlet pipe flange (233) Seal material (234) Fixture (240) Air flow direction (300) Water surface (310) Drainage pipe (320) Water pipe (330) Water valve (340) Pump (350) Water flow direction (400) Drill support pipe (410) Drill base material (411) Upper air hole (420) Drill Blade (421) Drill blade tip (422) Drill blade inner surface (423) Drill blade outer surface (424) Lower air hole (430) Inner space (440) Outer space

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Eito Matsuo Haraguchi, Isahaya 655-10 (72) Inventor Masatoshi Matsuo 2-12-7 Kachimachi, Nagasaki City Kingman 304 (72) Inventor Akiko Matsuo Isahaya Ichiharaguchi name 655-10 (72) Inventor Takuya Matsuo 1-2693-46 Higashi-Omura, Omura-shi F term (reference) 2D043 CA14

Claims (8)

[Claims] 1. A ground freezing method, wherein low-temperature air is blown into a drilled hole in a ground freezing method to freeze the wall surface of the drilled hole and the ground provided with the drilled hole. 2. A ground freezing method, wherein at least one excavation hole through which the excavation hole communicates and at least one excavation hole through which the low-temperature air flows out is provided, and the low-temperature air is blown into the excavation hole to form a wall surface of the excavation hole. And a method of freezing a ground provided with an excavation hole. 3. An air inlet pipe is inserted into an excavation hole in the ground freezing method, low-temperature air is blown through the air inlet pipe, and the air is discharged through a gap between the air inlet pipe and the excavation hole. And a method of freezing a ground provided with an excavation hole. 4. In the ground freezing method, a sealing device is provided on the outer periphery of the drill, and low-temperature air is blown into the sealing device, and the low-temperature air is passed through a space created between the drill hole and the drill support pipe. A method for freezing the ground, wherein the ground is frozen by feeding the excavated hole to the wall of the ground. 5. The ground freezing method according to claim 4, wherein at least one air hole is provided in the drilling drill and the support pipe to promote the freezing of the wall surface of the drilling hole and the ground provided with the drilling hole. . 6. The first, second, third and fourth aspects of the present invention.
6. The method of freezing ground according to claim 5, wherein a water supply pipe is inserted to supply the insufficient water. 7. The first, second, third and fourth aspects of the present invention.
6. The ground freezing method according to claim 5, wherein a drain pipe is inserted to extract excess water. 8. A ground freezing method according to claim 1, wherein the ground surface is covered with a curtain or the like, and the ground is frozen by surplus cold heat of low-temperature air flowing out of the excavation hole.