JP5116111B2 - Backing prevention device - Google Patents

Description

  The present invention is a propulsion method in which propulsion pipes are sequentially buried in the ground, and the propulsion pipe row is pushed back to the start shaft side by water pressure or earth pressure acting on the excavator face plate at the tip when the propulsion pipe is connected during propulsion. The present invention relates to a device that prevents the backing.

  In the propulsion method, the excavator is pushed by pressing the rear end of the propelling pipe row with the main push jack installed in the start shaft while cutting the ground in front with the face plate at the tip of the excavating machine equipped at the tip of the propelling pipe row. And a method of burying the propelling tube row at a predetermined position.

The connection of the propelling pipe during the propulsion construction is completed when one propulsion pipe is buried, the main jack is reduced in the start shaft, and the space between the propelling pipe and the main jack is A method is used in which a propulsion pipe is suspended and installed, and the rear end of the installed propulsion pipe is pressed with a main jack to connect to the previous propulsion pipe. However, under soil conditions with high groundwater pressure and earth pressure, large water pressure and earth pressure act on the faceplate at the tip of the excavator, so when the main jack is reduced when the propulsion pipe is connected, A backing phenomenon occurs in which the subsequent propulsion tube row is pushed back. For this reason, there is no space for installing the next propulsion pipe, the water stop rubber on the start pit wall is reversed by the removal of the propulsion pipe, groundwater and earth and sand are ejected into the start pit and flow out without water stoppage The problem that occurred.

For this reason, in recent years, in order to obtain a backing preventing force, an insert anchor system is often employed. In this method, a plurality of insert anchors are installed on both side surfaces outside the propulsion pipe, and a plurality of support plates are fixed to the insert anchor portion with a plurality of bolts. The support plate is a method in which the support plate is supported in contact with a receiving plate on a propulsion table installed on both sides of the propulsion pipe. The support plate is fixed with a plurality of bolts, and a relatively large backing reaction force can be obtained. In addition, as another method for preventing backing, there are a rod-shaped projecting rod that penetrates the propelling tube wall through the injection holes provided on both side surfaces of the propelling tube and projects outward by a predetermined length, and an inner side of the propelling tube. An inner distribution plate that is provided with an insertion hole at the position of the protruding rod and is in contact with the inner wall surface of the tube, an inner fixing bracket that fixes the protruding rod through the inner distribution plate, and an outer side of the protruding rod A cylindrical insertion tube is fixed to the outer distribution plate so as to cover the insertion insertion hole on the outer distribution plate installed so as to contact the outer wall surface of the tube by providing a fitting insertion hole at a position, and the front of the insertion tube. Backing force support metal fittings whose side surfaces are reinforced and fixed with a reinforcing material from the outer distribution plate, and an outer fixing metal fitting for fixing the end portion of the protruding rod from the insertion tube of the backing support metal fitting. A device that can easily prevent a large backing force. It has been developed.
JP 2008-82068 A

  In the insert anchor method described above, the number of insert anchors can be increased or decreased in accordance with the magnitude of the backing force. However, in the case of a large backing force, the insert anchor for fixing the support plate is used. There is a problem that the number of bolts becomes extremely large, and it takes a lot of time to install and remove bolts installed in the insert anchor, and the time required for propulsion work is remarkably reduced. In addition, a hole filling process of the insert anchor portion is also required, and more labor and cost are required when the number of installation is increased. Furthermore, the backing prevention device comprising an insertion tube inserted into a pair of protruding rods protruding outward from the injection hole is efficient simply by inserting the protruding rod into a previously provided injection hole for a lubricant or grout injection. Although it is a good method, it can easily prevent backing in a short time, but during the propulsion it is necessary to install a cover for preventing intrusion of groundwater and earth and sand, and reverse flow to prevent backflow when lubricating or grout is injected. The screw in the socket in the injection hole that is provided to install the stop valve is crushed by the projecting ridge that receives a large backing force, and the problem that the Mekura lid and check valve cannot be installed and the propulsion work cannot be performed occurs. Was. Further, when a large backing force is generated, there is a problem that cracks are generated in the concrete wall around the injection hole. For this reason, this invention is providing the backing prevention apparatus which can prevent safely even if it is big backing force, without trouble in propulsion construction.

The present invention is a backing prevention device for preventing a phenomenon in which a propelling pipe row is pushed back to the start shaft side by water pressure or earth pressure acting on the excavator face plate at the tip during propulsion pipe connection during propulsion construction.
A cylindrical connection socket that is internally threaded with a predetermined length in the radial direction from the inner surface of the wall so as to be orthogonal to the wall surface is provided at a predetermined position of the propulsion tube, and a cylindrical special socket is provided from the outer surface of the wall. And an injection hole that is connected so that the central axis is coaxial, and a cylindrical fitting rod that is in the same length as the special socket and that is inscribed in the special socket, at one end of the fitting rod The backing support fitting provided by connecting the bottom plate of the strong box body is fitted into the special socket from the outside of the propulsion pipe, and one side surface of the box body is attached to the outer periphery of the propulsion pipe. It is the backing prevention device which prevents backing by contacting and fixing to the movable fixed frame installed in the section.

  The connection socket of the injection hole is machined with an internal thread that is long enough to be fitted with a lid and check valve. The special socket that is connected to the connection socket is provided so that the connection socket and the central axis are coaxial. As the material of the special socket, a steel material having a high strength is used so that it can sufficiently withstand a large force received from the inserted fitting rod. When the special socket inner diameter is different from the connection socket inner diameter, a connection plate is attached to and integrated with the connection position of the special socket and the connection socket. The central portion of the connection plate is opened with substantially the same diameter as the connection socket and penetrates the special socket. The injection holes are installed at a plurality of locations in the circumferential direction in the middle portion of the propulsion pipe.

  The fitting hook of the backing support fitting is inscribed in the same length as the special socket in the injection hole. As the material of the fitting rod, a steel material having high strength is used, and the number of the fitting rods, the inner and outer diameters, and the like are determined by examining the expected backing force in advance.

The box body connected and fixed to one end of the fitting rod is constituted by four side plates and a bottom plate, and the top portion is in a released state. The bottom plate of the box has an opening with the same diameter as the inner diameter of the fitting rod. A fixing bolt is fitted from the top of the box material, inserted through the connection socket, and the fixing bolt is tightened on the inner surface of the propulsion pipe Tighten with a tool to fix the backing bracket.

  The shape of the movable fixed frame is manufactured by changing the shape of the movable fixed frame into a square or a polygonal shape so that the movable fixed frame surface is adjacent to the outer peripheral surface of the propelling pipe in accordance with the installation position of the injection hole. In order to prevent the moving fixed frame from moving rearward from the position, the moving blocking material is extended and fixedly supported from the front or rear of the start shaft wall. Since a large backing force acts on the moving fixed frame and the movement blocking material, a steel material such as H-shaped steel is used. In particular, in the case of taking a large backing force, a movement blocking material system that supports from behind is effective.

  Since the backing prevention device of the present invention is responsible for the backing force only by the insertion hook in the special socket installed between the wall outer surface of the injection hole of the propulsion pipe and almost the middle, the connection socket installed on the wall inner surface part has Since the backing force does not act, the inner screw of the connection socket does not hurt, and the installation of the cover lid and check valve necessary for propulsion can be performed reliably. In addition, the insertion hole of the injection hole is reinforced with a special socket, and even if a large backing force is applied, it is distributed and transmitted to the concrete surface via the special socket. So that cracks and breakage no longer occur.

  When the propulsion pipe is connected during propulsion construction, the backing that pushes the propulsion pipe row back to the start shaft side by water pressure or earth pressure acting on the excavator face plate at the tip is safe and reliable by using multiple injection holes. The technology that can be prevented.

  FIG. 1 is a cross-sectional view illustrating a backing support fitting of the present invention. The backing support fitting 1 is composed of a box 3 composed of four side plates and a bottom plate, and a cylindrical fitting bar 4 fixed at the center of the bottom plate of the box 3. A hole is opened in the fitting portion 4 of the bottom plate with the same diameter as the inner diameter of the fitting rod 4. From the hole in the bottom plate, a fixing bolt 5 having a length protruding from the inner surface of the wall of the propelling tube through the fitting rod 4 is fitted, and a screw portion is provided at the lower end of the fixing bolt 5 to tighten the fastener. 6 is attached.

  The fitting rod 4 is manufactured with a predetermined length, and the inner and outer diameters and the number of the fitting rods 4 are changed depending on the backing force. Usually, it is larger than the outer diameter of the connection socket 7 connected to the lower end. The fitting rod 4 is firmly fixed to the bottom plate of the box 3 in order to reliably transmit the backing force received by the propulsion pipe to the box 3. As a fixing method, a conventional welding technique or the like is generally used.

  The box 3 is made of a strong steel material or the like so as not to be deformed or damaged against the backing force transmitted through the fitting rod 4.

  FIG. 2 is a cross-sectional view illustrating the injection hole of the present invention. The injection hole 2 is provided with a cylindrical connection socket 8 that is internally threaded with a predetermined length in the radial direction from the inner wall surface of the propulsion tube 10, and a cylindrical special socket 7 is provided at the center of the connection socket 8 from the outer wall surface. Connected to be coaxial with the shaft. Usually, the inner diameter of the special socket 7 is larger than the inner diameter of the connection socket 8. When the inner diameter of the special socket 7 and the inner diameter of the connection socket 8 are different, the connection plate 9 is installed at the connecting portion and integrated. The central portion of the connection plate 9 is opened with substantially the same diameter as the connection socket 8 and penetrates the special socket 7.

  The inner diameter of the special socket 7 is set to a size that can accommodate the outer diameter of the fitting rod 4 described above. The special socket 7 and the connection socket 8 constituting the injection hole 2 are integrated and constructed at the time of concrete placement, and have a strong structure.

  FIG. 3 is a cross-sectional view illustrating the backing prevention situation of the present invention. At the top of the propulsion tube 10, an injection hole 2 to which a special socket 7 and a connection socket 8 are connected is provided. In the special socket 7 of the injection hole 2, the fitting hook 4 of the backing support fitting 1 is fitted, and a movable fixed frame 11 is fixed in contact with the side plate position of the upper box 3.

  From the top of the box 3, the fixing bolt 5 is projected from the fitting rod 4 through the connection socket 8 to the inside of the propulsion pipe 10, and the fixing bolt 5 is tightened by the fastening tool 6 on the inner surface of the propulsion pipe 10. The backing support bracket 1 is fixed.

  When the propulsion jack 10 is reduced when the propulsion pipe 10 is connected, a backing force acts on the propulsion pipe 10 due to water pressure or earth pressure acting on the face plate at the tip of the excavator. The propulsion tube 10 tends to be pushed back by the backing force, but the fitting rod 4 fitted in the special socket 7 of the injection hole 1 of the propulsion tube 10 prevents the propulsion tube 10 from moving backward. The number and size of the fitting rods 4 are studied so as not to be deformed or damaged with respect to a backing force assumed in advance.

  The shape of the movable fixed frame 11 that receives the backing force from the box 3 is determined according to the number of injection holes 1 determined by the backing force. When the injection holes 1 are planned at three points on the top and both sides of the propelling tube 10, the shape of the movable fixed frame 11 is a gate shape so that the surface of the movable fixed frame 11 is adjacent to each injection hole 1 position.

  The support of the movable fixed frame 11 has a structure in which a movement blocking material (not shown) is extended and fixed from the front or rear of the start shaft wall. The movable fixed frame 11 and the movement blocking material are manufactured with high-strength H-shaped steel material or the like so as not to be deformed or buckled by the backing force.

  When the connection of the propulsion pipe 10 is completed, the main push jack is brought into contact with the end face of the propulsion pipe 10 at the rearmost portion, and the propulsion preparation is completed. When the propulsion preparation is completed, the backing support fitting 1 fitted in each injection hole 2 is removed, and a check valve and a cover lid are attached to the connection socket 8 and the propulsion work is resumed.

  It can be applied to propulsion work under soil conditions with high groundwater pressure and deep soil cover.

It is sectional drawing explaining the backing support metal fitting of this invention. It is sectional drawing explaining the injection hole of this invention. It is sectional drawing explaining the backing prevention condition of this invention.

DESCRIPTION OF SYMBOLS 1 Backing support metal fitting 2 Injection hole 3 Box 4 Insertion hook 5 Fixing bolt 6 Fastening tool 7 Special socket
8 Connection socket 9 Connection plate 10 Propulsion tube 11 Moving fixed frame

Claims (1)

In the backing prevention device that prevents the phenomenon where the propelling pipe row is pushed back to the start shaft side by the water pressure and earth pressure acting on the excavator face plate at the tip when propelling pipe is connected during propulsion construction,
A cylindrical connection socket that is internally threaded with a predetermined length in the radial direction from the inner surface of the wall so as to be orthogonal to the wall surface is provided at a predetermined position of the propulsion tube, and a cylindrical special socket is provided from the outer surface of the wall. And an injection hole that is connected so that the central axis is coaxial, and a cylindrical fitting rod that is in the same length as the special socket and that is inscribed in the special socket, at one end of the fitting rod The backing support fitting provided by connecting the bottom plate of the strong box body is fitted into the special socket from the outside of the propulsion pipe, and one side surface of the box body is attached to the outer periphery of the propulsion pipe. Backing prevention device characterized in that backing is prevented by abutting and fixing to a movable fixed frame installed in a section.

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