JPH04366298A - Temporary sheathing work for cut face - Google Patents

Abstract

PURPOSE:To exactly shield a cut face by a simplified operation as needed. CONSTITUTION:In a method of closing a cut face on the tip of a tube having a cutting edge on its tip, which is being advanced under the ground, a rigid frame 3 is housed in the cutting edge 2 and an expandible air bag 4 made of a flexible, water-stopping material is positioned on the front of the frame inside of the cutting edge 2. A fluid is supplied into the air bag to expand it in order to close the cut face.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a face temporary earth retaining method that can effectively prevent the inflow of face earth and sand into pipes.

0002

[Prior Art] When a propulsion method is used for an aquifer or a groundwater aquifer, it is necessary to lower the groundwater level below the propulsion level by using the well point method or the deep well method in combination. This is to prevent a large amount of earth and sand from flowing into the propulsion pipe together with water.

0003

[Problems to be Solved by the Invention] When a water pump malfunctions or a power outage occurs, water pumping operations are forced to be suspended until the faulty part is repaired or the power is restored. If repairs and restoration take time, the groundwater level may rise above the propulsion pipe. In such a case, since the propulsion pipe does not have a function to prevent the intrusion of earth and sand, a large amount of earth and sand is allowed to flow into the propulsion pipe, and there is a risk of causing a ground cave-in accident.

0004

[Object of the present invention] The present invention has been made in view of the above points, and its purpose is to provide a face temporary earth retaining method that can reliably shield the face with simple operation when necessary. be.

[0005]

[Means for Solving the Problems] The present invention is a method of closing the face at the tip of a tube for propelling underground by attaching a propulsion cutter to the tip, and in which the inside of the propulsion cutter has rigidity. An inflatable airbag made of a flexible and waterproof material is located inside the propulsion blade opening and in front of the frame, and fluid is supplied to the airbag. This is a face temporary earth retention method in which the earth is inflated and the face is closed.

[0006]

[Structure of the present invention] The present invention will be explained below with reference to the drawings.

<A> Temporary Earth Retaining Means FIG. 1 shows a conceptual diagram of the earth retaining means for the face. A cylindrical propulsion blade 2 is attached to the tip of the propulsion tube 1 to propel the tube underground, as in the conventional case. In the present invention, when temporary soil retention is required, a rigid frame 3 is assembled inside the propulsion cutting edge 2, or a bag-shaped airbag 4 is positioned in front of the frame 3 that has been attached in advance. By supplying air to the air bag 4 and inflating it, the tip of the propulsion tube 1 is closed.

<B> Frame The frame 3 is a member that prevents the inflated airbag 4 from retreating, and also functions as a reinforcing member for the propulsion blade 2. Furthermore, the frame is formed by combining steel materials, etc., and there are no restrictions on the shape of the combination of special steel materials. In addition to the above, frame 3
What is required is a structure that has an outer diameter that cannot pass through the propulsion blade opening 2 and does not inhibit the uptake of earth and sand during propulsion. In addition, the frame body 3 is not used during propulsion, and steel material is carried in when installing the airbag 4.
It can be assembled inside.

<C> Airbag The airbag 4 is manufactured in a bag shape according to the diameter of the propulsion tube 1 using a material that is strong enough to withstand earth pressure and waterproof. A supply hose capable of supplying air, etc. is attached to a part of the airbag 4. The size of the airbag 4 may be such that it can be pressed against the inner circumferential surface of the propulsion blade 2 at least when inflated. The inflation fluid of the airbag 4 may be a gas such as air, a fluid such as water, or a foaming material.

0010

[Operation] Next, the method of retaining earth at the cutting edge will be explained using the propulsion method as an example.

<A> Propulsion FIG. 2 shows a sectional view of the face during propulsion. Prior to the promotion work, lower the groundwater level below the promotion level using the well point construction method or deep well construction method. Then, thrust is applied from the base end of the propulsion tube 1, which has the propulsion blade 2 attached to the tip, to continue propulsion toward the left side of the drawing. The earth and sand taken in through the opening of the propulsion blade 2 is transported to the starting side and discharged.

<B> If the underground water level rises due to a failure of the temporary storage pump or a power outage accident, the folded airbag 4 is placed in front of the frame 3 as shown in FIGS. 1 and 3. The end of the supply hose 5 extending from the airbag 4 is connected via a valve 6 to a fluid supply device such as a compressor (not shown). Then, supply of air to the airbag 4 is started. As a result, the folded airbag 4 begins to expand inside the propulsion blade 2 and in front of the frame 2, and the peripheral surface of the airbag 4 is pressed against the inner peripheral surface of the propulsion blade 2. The propulsion blade opening 2 is closed. Therefore, since the face earth and sand are blocked by the airbag 4, the earth and sand are prevented from flowing into the propulsion pipe 1. During this time, repairs to the water pump and restoration of power transmission will be carried out.

<C> Release of temporary soil retention After the water is pumped up again to lower the groundwater level, the valve 6 is opened to deflate the airbag 4 and the water is recovered. After recovering airbag 4, propulsion work will resume.

[0014]

[Other Embodiments] As shown in FIG. 4, an annular seal 41 may be attached continuously to the inner circumferential surface of the propulsion cutting edge 2 and the circumferential surface of the airbag 4 which is to be in contact with it by adhesive or the like. The annular seal 41 can be made of soft rubber with a thickness of about 5 mm and a width of about 100 mm, for example. Furthermore, an annular sealing material 43 that seals off water between the airbag 4 and the front surface of the propulsion blade opening 2 is provided.
You can also attach it. The sealing material 43 is fixed to the airbag 4 side with adhesive or the like.

[0015]

[Effects of the Invention] Since the present invention is as explained above, the following effects can be obtained.

[0016] <A> The intrusion of earth and sand into the face can be reliably prevented by a simple operation of placing a small folded air bag at the temporary soil retaining position and inflating it at the face.

<B> Since the airbag can be deflated and recovered, the face can be easily released.

<C> Since the airbag is flexible, it has good adhesion to the inner circumferential surface of the tube and is highly reliable in terms of watertightness.

[Brief explanation of the drawing]

[Figure 1] Explanatory diagram of equipment used in the temporary earth retention method of the present invention

[Figure 2] Cross-sectional view of the face during propulsion

[Figure 3]
Cross-sectional view of the face during temporary earth retention

[Figure 4] Explanatory diagram of another embodiment

Claims (1)

[Claims] Claim 1: A method of closing the face at the tip of a tube for propelling underground by attaching a propulsion cutter to the tip, the method comprising: housing a rigid frame inside the propulsion cutter; An inflatable airbag made of a flexible and waterproof material is positioned inside the cutting edge and in front of the frame, and fluid is supplied to the airbag to inflate it and close the face. ,
Face temporary earth retaining method.