JPS6218718B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pipe burying method, and particularly to a pipe burying method for ground with a large amount of groundwater.

[Conventional technology] When burying water supply and sewage pipes and protection pipes for various cables underground across roads and railway tracks, this method is used to bury the pipes without excavating above ground. A method has been implemented in which a shaft is excavated from the shaft, and a horizontal excavation device such as a horizontal auger screw is used to excavate underground from within the shaft and push the pipe to be buried.

However, with this type of pipe burying method, no special problems arise if the excavated ground is above the groundwater level and does not contain water, but if the pipe is installed by excavating ground that contains surface water such as a water-retaining sand layer, When buried, there is a drawback that when excavating with a horizontal excavation device such as an auger screw, groundwater flows into the casing of the horizontal excavation device and into the shaft, causing the ground to cave in and sink during excavation.

In order to solve this problem, a push pipe, such as a steel pipe and an auger, is pushed into the ground through a hole in the earth retaining wall of the shaft, and the auger is rotated to remove the soil, and the rotation axis of the auger is a hollow pipe. It is rotated by a motor in the machine room and has a passageway for sending muddy water into an opening near the tip of the auger. Furthermore, an earth removal chamber is provided at the bottom of the base of the steel pipe, and the earth carried by the auger is collected in the earth removal chamber. The earth removal chamber is equipped with an opening/closing plate on the upper and lower levels, and since the mud water pressure is normally a little higher than the groundwater pressure, the opening/closing plate suppresses the flow of mud into the earth removal chamber when excavation is not in progress. A mud water horizontal auger construction method is known from Japanese Patent Application Laid-Open No. 136713/1983, in which a check valve is installed in the hole to prevent the mud pressure from decreasing in the borehole when drilling is stopped. A plurality of shelves having an appropriate depth and having a horizontal or slightly downward slope in the direction of propulsion are provided at the rear of the pipe body, and a closing plate whose upper part serves as a rotation axis is provided at the rear end of each shelf,
Furthermore, a watertight bulkhead that closes off the entire cross section of the pipe is installed at an appropriate rear position, and the top of the bulkhead is connected to a water tank installed near the propulsion shaft to apply the required water pressure between the closing plate and the bulkhead. Attach a water pipe that has been properly installed. On the other hand, an inclined pipe is provided at the bottom of the partition wall and is opened toward the rear of the pipe body, and the end portion of the pipe is bent vertically and is opened by providing a watertight opening/closing valve. Next, the trolley bucket is positioned and fixed in a watertight manner at the lower opening of the valve, which matches the opening shape of the upper opening of the trolley bucket. With the watertight opening/closing valve open, the earth and sand taken into the pipe body by the propulsion of the pipe body are scraped up underwater along the valve provided at the bottom of the bulkhead, and removed to the vertical end of the pipe. It is then dropped downwards, passes through an opening/closing valve, and is deposited in a trolley cart. After that, the operation of stopping scooping up the earth and sand, closing the opening/closing valve, opening the anchorage of the troll bucket, capturing the earth and sand in the troll bucket, and taking it out to the outside of the pipe body is repeated. The underwater propulsion method used in the shield method or propulsion method, in which the pipe body is sequentially propelled while keeping the cutting edge completely submerged while transporting the earth and sand to the outside, was published in Japanese Patent Application Laid-Open No. 1983-
It is known from Publication No. 26412.

[Problems to be Solved by the Invention] In the above-mentioned prior art, the former one transports muddy water to the ground through the hollow rotating shaft of the auger, while the latter one has a water pressure chamber at the cutting edge.
This water pressure chamber and tank are connected in communication, and both cannot withstand groundwater pressure sufficiently due to the liquid in the casing that houses the excavation equipment, so they cannot be kept in a sufficiently stable state against ground subsidence. The problem was that it was difficult to expect.

Therefore, an object of the present invention is to provide a pipe burying method that reliably prevents ground subsidence and allows work to be carried out in a stable state.

[Means for solving the problem] The buried pipe construction method of the present invention includes disposing a casing within the buried pipe, disposing an excavation device within the casing,
In the pipe burying method, in which a buried pipe is pushed forward by a propulsion device in the shaft while excavating with this excavation equipment, and excavated soil is discharged through the casing, the soil discharge port of the casing and the closed soil discharge tank are connected for communication. At the same time, the liquid is supplied to the soil removal tank until the liquid is filled in the casing and the soil removal tank, and when the liquid is filled, the supply is stopped and both are connected in a liquid-tight state filled with liquid. This filled liquid allows excavation and pushing of the buried pipe while resisting the pressure of groundwater flowing into the casing.

[Example] Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 6.

Fig. 1 shows the preparation state, and 1 is a pipe burying device, which is inside a casing 2 and a shaft 3, in which a digging device 9 such as an earth auger is installed inside and a pipe burying pipe 10 is installed outside. The tank 4 is connected to a closed soil removal tank 4 installed in the tank 4 in a liquid-tight state filled with liquid.

Further, a liquid such as water is supplied to the closed earth removal tank 4, and the liquid supply is finished when the inside of the casing 2 and the earth removal tank 4 are filled with the liquid C. 6 is a water stop grout for starting, 7 is a propulsion jack, and 8 is a bearing wall.

Figure 2 shows the casing 2 and the closed soil removal tank 4.
This figure shows a state in which the excavation device 9 is propelled while resisting the water pressure of the underground water inlet by the liquid filled inside, and the front surface 5 of the face is moved by moving the excavation device 9 forward from the state shown in FIG. Horizontal excavation is performed with the front face 5 open in this manner, and the excavation device 9 flows into the tank 4 from the excavation inlet 4a. Incidentally, along with the excavation, the buried pipe 10 is pushed forward as usual.

Figure 3 shows the operating state when the tank 4 is full of excavated soil due to excavation, and the front face 5 and the excavated soil inlet 4a of the tank 4 are closed by seals, valves, etc. It's summery. 6a is a water stop grout inside the excavation device 9. Further, the connecting port 2a between the casing 2 and the tank 4 is also closed. In this case, since the front surface 5 of the face is in a closed state, no inconvenience occurs even if the water stop grout 6a and the connecting port 2a are in an open state. Note that the front face 5 is closed by moving the excavation device 9 backward.

FIG. 4 shows a state in which the buried pipe 10 is connected to the excavation device 9 and the tank 4 is transferred for discharging the excavated soil. In the tank 4, a connector (not shown) is separated, moved to the ground, and the waste soil is discharged.

FIG. 5 shows that the soil removal tank 4 without soil removal A is connected to the casing 2 from the state shown in FIG. 4, and the connection port between the casing 2 and the tank 4 is opened as shown in FIG. After the pipe is connected in a liquid-tight state filled with liquid, horizontal excavation and pushing of the pipe are repeated as shown in Fig. 2, and the state is shown in which the shaft 3a is reached, and 6b is the water stop grout for reaching the pipe. It is.
Moreover, the inside of the excavation device 9 is drained. Note that the water-stop grout 6a in the casing 2 in FIG. 4 is destroyed and removed by the rotational drive of an excavation device 9 such as an earth auger.

FIG. 6 shows the state in which the equipment has been removed and the pipes have been installed. Buried pipe 1 between the shafts 3 and 3a on both sides
0 penetrates, there is no risk of underground water flowing out, and the equipment can be easily removed.

The pipe burying method of this embodiment is as described above and has the following effects.

That is, first, the drilling equipment 9 is buried inside the pipe 1.
The casing 2, each of which is provided with 0 on the outside, and a closed soil removal tank 4 installed in the shaft 3 are connected in a liquid-tight state filled with liquid C, and the filled liquid C causes the inside of the casing 2 to be Since the excavation and the underground pipe 10 are carried out while resisting the water pressure of the groundwater flowing into the pipe, it is possible to reliably prevent the subsidence of the excavated ground due to the outflow of groundwater.Moreover, the simple structure of the device allows for easy operation. is possible.

Second, a closed earth removal tank 4 is installed in the shaft 3, and the closed earth removal tank 4 and the casing 2 are connected in a liquid-tight state filled with liquid. By opening and closing the soil discharge inlet 4a, the equipment and operation are simplified to enable the pipe burying method while preventing the discharge of groundwater and preventing subsidence of the excavated ground. The cost of burying pipes will be significantly reduced.

Thirdly, since the closed soil removal tank 4 is used, the disposal of the soil removal is carried out using the buried pipe 10 and the excavation device 9.
This can be easily done by moving the tank 4 at the same time as the connection, and the work efficiency is also excellent.

Fourthly, because the closed soil removal tank 4 was used,
The earth removal tank 4 and the casing 2 can be connected in a fluid-tight state filled with liquid C to withstand the water pressure of the underground water inlet by a simple operation of supplying liquid C to the tank 4, and By closing the discharge inlet 4a of the tank 4 at the front face 5, it becomes possible to separate and move the tank 4 for discharging the waste soil, thereby improving work efficiency.

Note that the present invention is not limited to the above-mentioned embodiments, and various modifications can be made within the scope of the gist of the present invention.

[Effects of the Invention] The present invention connects the casing containing the excavation equipment and the sealed earth removal tank in the shaft in a liquid-tight state filled with liquid, thereby reliably preventing ground collapse and facilitating smooth excavation. We can provide a pipe burying method that allows pipe burying.

[Brief explanation of the drawing]

FIGS. 1 to 6 are schematic explanatory diagrams showing the sequence of steps. 1...Pipe burial device, 2...Casing, 3...
Vertical shaft, 4... Closed earth removal tank, 7... Propulsion device, 10 Buried pipe, C... Liquid.

Claims (1)

[Claims] 1 In a buried pipe construction method in which a casing is placed inside a buried pipe, and while excavating with an excavating device inside the casing, the buried pipe is pushed forward by a propulsion device in a shaft and the excavated earth and sand is discharged through the casing. The discharge port and the closed soil discharge tank are connected in communication, and the liquid is supplied to the soil discharge tank until the liquid is filled in the casing and the soil discharge tank, and the supply is stopped when the liquid is filled. A pipe burying method characterized in that the two are connected in a liquid-tight state filled with liquid, and excavation and pushing of the buried pipe are performed while resisting the water pressure of groundwater flowing into the casing by the filled liquid. .