JPH0684632B2 - Small diameter tunnel drainage method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a small diameter tunnel drainage method for preventing landslides.

[Problems to be Solved by Prior Art and Invention]

A method of removing groundwater has long been used as a typical method for landslide countermeasures.

This groundwater drainage work has the types shown in the table below depending on whether the groundwater to be drained is shallow or deep.

Of these, the most commonly used water collection boring work for the purpose of removing deep groundwater has the advantage of being inexpensive and easy to construct, but in the landslide area where the water collection pipe is thin, it takes 3 to 5 years. It often loses its function due to clogging. Therefore, although pipes have been recently washed, they are not yet popular. In addition, the pipe is thin and difficult to clean, and a PVC pipe is used as the water collection pipe, but it may be cut off and lose its function in a landslide area with large movements.

Although the drainage tunnel has a large cross-section, it has a large collection and drainage capacity, but since it mainly uses artificial excavation, it has drawbacks such as high risk of accidents such as gas protrusion, oxygen deficiency, and falling table, and high cost. In addition, since it is necessary to excavate from the outside of the landslide block to the stable base rock below the landslide block, the construction length will be long.

Therefore, we wondered if it is possible to safely and relatively inexpensively construct a large-diameter pipe that has a large collection and drainage capacity and is easy to maintain.
Utilization of the small-diameter tunnel drainage method of the present invention as a landslide countermeasure work on a landslide area has been studied.

First, we consider the problems of water collection boring.

At the beginning, it was mentioned that the water collection boring work has the drawback that it is easily clogged while it is cheap and easy to construct. In addition to this, the disadvantage of this method is that the water collecting capacity is poor because the pipe is thin, the direction of the boring cannot be controlled, in other words, even if you try to open it straight, it hits the rock or changes due to changes in the soil quality etc. There are some drawbacks. Therefore, water with pressure existing in a limited range near the sliding surface, which is considered to adversely affect the landslide, must be drained as efficiently as possible.

In order to drain such water efficiently, the following items are required.

○ Increase the number of water collection pipes.

○ The area of the strainer is large and groundwater can easily penetrate into the pipe.

○ A catchment pipe can be attached to the groundwater zone.

○ The cross section should have enough margin to prevent functional deterioration even if water stains are attached.

From the above research based on the test construction, it was confirmed that it is necessary to attach a large number of large diameter pipes to the groundwater zone, which is not possible with the method using the ordinary boring machine.

As a method for satisfying these requirements, the present invention has been completed with a view to adopting a propulsion method in which a large-diameter pipe can be attached while controlling the direction.

The propulsion method is a method widely used for pipe work in urban areas and railroad crossings. There are many types of this method, such as propulsion method and cutting edge shape, but the main ones are as shown in the following table.

The press-fitting method is a method of pushing the pipe body with a jack and is suitable for soft soil. By installing a drilling head, it is possible to deal with slightly hard soil and gravel. In addition, since the tube body does not rotate, it is easy to correct the direction.

The auger method is a method in which the ground is excavated by an excavation head and a pipe is pushed by a jack. Depending on the type, it is possible to handle soft rock such as mudstone by selecting the shape of the excavation head. This method is also easy to correct the direction.

While the press-fit type and the auger type do not normally rotate the pipe body, the horizontal boring type is a method of excavating the ground while rotating the pipe body. A wide range of geological features can be supported by selecting bits as in general boring. But,
Direction correction is impossible.

In addition to the above excavation method, there is a fronte jacking method in which a pipe is towed from the arrival side by a PC steel wire or the like. This method has the advantage that it can be constructed with a small-scale device, but the applicable soil quality is limited to soft cohesive soil.

The above is an outline of the construction methods. Among these construction methods, considering the applicable soil quality and the accuracy of pipe attachment, the auger excavation method must be adopted as the construction method that can be applied to the landslide area (third stage). Judgment was made, and as a result of the test study, the present invention was completed.

[Means for Solving the Problems]

 The gist of the present invention will be described with reference to the accompanying drawings.

A small head 2 with earth retention is provided at a position where it can be excavated in a substantially straight line toward the groundwater part 1 of the landslide danger zone, and a propulsion machine installation part 4 in which a reaction force receiving pile 3 is buried is provided in front of the small mouth 2, or A starting pit 14 is digging at a position where it can be drilled in a substantially straight line toward the groundwater part 1, a reaction force receiving plate 15 is provided in the starting pit 14, a propulsion device installation part 4 is provided, and the propulsion device installation part 4 is propelled. The machine 5 was installed in a state where the reaction force received by the propulsion machine 5 was supported by the reaction force receiving pile 3, and the strainer steel pipes 7 having the strainer holes 6 formed on the outer circumference of the large diameter steel pipe having a pipe diameter of 200 to 800 mm were sequentially welded. When the buried drainage steel pipe a is pushed by the propulsion section 5 ′ of the propulsion device 5 with a drainage gradient, the auger bit 9 is arranged at the most distal end of the buried drainage steel pipe a.
A rotation drive unit for rotatably providing an auger 10 rotatably in the buried drainage steel pipe a for rotating the auger 10 on the propulsion device 5.
11 is provided, the auger bit 9 is rotated to excavate the propulsion hole 13 toward the groundwater, the earth is discharged by the auger 10, and the buried drainage steel pipe a is gradually extended and embedded, and the strainer steel pipe 7 at the tip is grounded. Reach reservoir 1 and auger bit 9
, Auger 10, propulsion device 5 and reaction force receiving pile 3 are removed, groundwater is collected into the underground drainage steel pipe a through the strainer hole 6 of the strainer steel pipe 7, and the collected groundwater is discharged to the surface of the ground for landslide. The present invention relates to a small-diameter tunnel drainage method, which is characterized by preventing

[Work]

 The propulsion unit 5 is installed in the propulsion unit installation unit 4.

The propulsion unit 5'of the propulsion unit 5 is retracted, the auger bit 9 and the auger 10 are attached to the first strainer steel pipe 7, set on the propulsion unit 5, and pushed into the soil by the propulsion unit 5 '. The auger bit 9 is rotated by the rotation driving unit 11 of the above to excavate the propulsion hole 13 and at the same time, the auger 10 is rotated to expel the excavated soil, and when the embankment is advanced in one soil, the propulsion unit 5'is retracted again. The next strainer steel pipe 7 is attached, the previous strainer steel pipe 7 is welded, the auger 10 is connected, and the auger bit 9 and the auger 10 are advanced again by advancing the propulsion device 5.
Rotate by the rotation drive unit 11 and embed the next one,
By repeating this operation, the buried drainage steel pipe a is attached to the drainage gradient and extendedly buried toward the groundwater reservoir 1.

When the work machine is removed after the excavation work is completed, groundwater or the water is collected through the strainer hole 6 by the buried drainage steel pipe a and discharged to the surface of the ground, so that landslide is prevented.

〔Example〕

 The strainer steel pipe 7 has a workability of about 2 m.

The strainer steel pipe 7 to be joined is hung with a crane on the mounting part of the propulsion device 5 while the auger 10 is arranged, and the auger 10 is connected to the auger of the front pipe and the rotary drive unit 11, and the front pipe and the rear pipe of the strainer steel pipe 7 are connected. Weld the pipes together.

After that, the propulsion unit 5'of the propulsion unit 5 is moved forward to rotate the drive unit.
Rotate auger bit 9 and auger 10 with 11.

FIG. 7 illustrates a case where a large catchment well 8 of about 7 m × 3 m is provided on the way to facilitate the construction work of the buried drainage steel pipe a or to enable drainage from the catchment well 8 in collecting water. There is.

Further, FIG. 8 illustrates a case where a vertical drainage channel 12 is provided instead of the water collection well 8.

If the tip end blade opening 7'of the most advanced strainer steel pipe 7 is slightly bent, the embedding direction of the buried drainage steel pipe a changes in that direction, and the direction can be slightly changed.

[Advantages of the Invention] 1. The features of this method are: 1. Since the diameter of the pipe is large and the strainer holes are formed over the entire length, the water collection capacity is excellent and the maintenance is easy.

2. You can propel while controlling the direction.

3. Since it uses steel pipes, it has more strength than PVC pipes.

4. The construction cost is lower than that of collecting wells and drainage tunnels.

5. Since the sliding surface can be directly penetrated in the landslide block, water near the sliding surface can be easily discharged.

6. As it is constructed on the surface of the earth, it is superior in safety compared to drainage tunnel construction.

And so on.

[Brief description of drawings]

The drawings show an embodiment of the present invention.
FIGS. 3, 3 and 4 are explanatory views of a conventional propulsion method, FIG. 5 is an explanatory view of the method of the present invention, FIG. 6 is a perspective view of a strainer pipe of the present invention, and FIGS. It is explanatory drawing of another Example of invention. a: buried drainage steel pipe, 1 ... groundwater part, 2 ... small amount, 3
…… Reaction force receiving pile, 4 …… Propulsion machine installation section, 5 …… Propulsion machine,
5 '... Propulsion Department, 6 ... Strainer hole, 7 ... Strainer steel pipe, 9 ... Auger bit, 10 ... Auger, 11 ...
… Rotation drive, 13 …… Propulsion hole, 14 …… Starting shaft, 15 …… Reaction force receiving plate.

Claims (1)

[Claims] 1. An earth retaining head is provided at a position where the groundwater part of the landslide danger zone can be excavated in a substantially straight line, and a propulsion machine installation section in which a reaction force receiving pile is buried is provided in front of this mouth, or a landslide danger zone A start pit is dug at a position where it can be drilled in a substantially straight line toward the groundwater section, a reaction force receiving plate is provided at this start pit, and a propulsion unit installation section is provided. Install the reaction force so that it is supported by the reaction force receiving pile.
When a buried drainage steel pipe, in which strainer steel pipes with a strainer hole formed on the outer periphery of a large diameter steel pipe of about 200 to 800 mm are sequentially welded, is pushed by the propulsion unit of the propulsion machine with a drainage gradient, the auger is placed at the leading edge of this buried drainage steel pipe. Arrange the bit,
An auger that rotates this auger bit is rotatably installed in the buried drainage steel pipe, a propulsion unit has a rotation drive unit that rotates the auger bit, and the auger bit is rotated to excavate a propulsion hole toward groundwater and excavate the soil with the auger. The drainage steel pipe is gradually extended and buried, the strainer steel pipe at the tip is made to reach the groundwater reservoir, the auger bit, auger, propulsion device and reaction force receiving pile are removed, and the groundwater strainer is a strainer for steel pipe. Water is collected in the buried drainage steel pipe through the hole,
A small-diameter tunnel drainage method characterized by discharging this collected groundwater to the surface to prevent landslides.