JPH0762433B2 - Tubular receding prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a shield machine and a method for preventing backward movement of a propulsion pipe in various propulsion works.

<Prior art> A starting shaft is installed in a predetermined position, and a thrust method of a jack that receives a reaction force from a bearing wall installed in the rear part of the shaft pushes the pipes one by one into the ground. Unlike the excavation method, the excavated surface on the ground is limited to the vertical shaft, and is used as an effective method for construction on heavy traffic roads and urban areas. As a general propulsion method, a blade entrance or a shield excavator is attached to the tip of the buried pipe to reduce the propulsion resistance while excavating the earth and sand with human power or a machine, and a shield is provided by a push jack installed in the starting shaft. Press the rear end of the machine to press the shield machine and the pipe to the ground. When extension of the jack is completed, the jack is reduced, a steel spacer matching the length of the jack stroke is inserted in the front part of the jack, and the jack is extended again to embed the shield machine and pipe. . Furthermore, in recent years, propulsion has become more frequent under soil conditions with a lot of groundwater and soft soil conditions without independence, and the method of mechanical excavation is often adopted.The shield excavator also uses a natural excavator inside the excavation chamber behind the cutter plate provided in the front. The mud-type shield machine and earth-pressure balance-type shield machine, which keep the cutting ground down while filling the pressurized mud and the excavated earth and sand against the water pressure and the earth pressure, have been widely used.
However, when using these shield machines, the excavation chamber in the front part of the shield machine is filled with pressurized mud and excavated earth and sand, and is balanced with the face earth pressure and water pressure. , Always exerting great force to push back. Therefore, at the initial stage of propulsion, the frictional force of the shield machine and the outer circumference of the pipe is smaller than the face earth pressure and water pressure, so the pressure of the original jack should be reduced when the original push jack is reduced or the next pipe is installed. It is often the case that the shield machine and the pipe are retracted, and in the shaft, earth and sand and groundwater are ejected from the outer periphery of the pipe as the pipe and the like recede. It is causing a depression. At the tip of the shield machine, as the shield machine retreats, the earth and sand above the shield machine are drawn into the front part of the shield machine, causing the ground around the shield machine to sink or sink.

For this reason, in the prior art, in order to prevent the shield excavator and pipes from retreating, a wire or chain is wound around the outer periphery of the shield excavator or pipe in the shaft, and both ends of the wire or chain are moved to the front of the shaft. A method of fixing the pipe to a water blocking wall and tightening the pipe with a traction device or a method of preventing the pipe from retreating by tensioning both sides of the rear end of the pipe and the front of the shaft with a traction device are used.

<Problems to be Solved by the Invention> In the backward prevention device for a pipe according to the above-mentioned prior art, a wire, a chain, and a tractor that are tightening the pipe body in order for the pipe body to move forward and move with the extension of the original push jack. Under the present circumstances, the device is loosened and the traction device is tightened each time the jack extends one stroke. Since the extension of one stroke of the original push jack is completed and the traction device is tightened, the reduction work of the jack must be interrupted during the tension by the traction device.
Due to the frequent tightening work, the propulsion speed is greatly delayed, resulting in a longer construction period and increased construction costs. Further, the propulsion work is complicated due to the frequent tightening work, and there are problems that forgetting to tighten the traction device and deterioration of the propulsion accuracy. Therefore, the present invention is to provide a pipe trough retraction prevention device for the purpose of solving such a problem.

<Means for Solving the Problems> The pipe ditch retracting prevention device of the present invention which solves the above problems is such that a plurality of fixtures are brought into contact with the outer surface of the pipe ditch inside the annular body at the front part inside the starting shaft. The fixture is characterized in that the restraint force is released when the pipe is advanced, and the fixture is pressed against the pipe to prevent the pipe from retreating.

<Action> A plurality of fixtures arranged inside the annular body are arranged so as to come into contact with the outer surface of the pipe, and when the pipe is moving forward due to the extension of the original push jack, the fixture makes jack thrust. When the abutment is released due to, the fixture comes into contact with the outer periphery of the abutment again, and further, the abutment begins to retreat due to the pushing back force due to the earth pressure and water pressure at the tip of the shield machine. At times, the fixture can press against the conduit to prevent it from retracting.

In this manner, when the pipe is retracted, the device is a device that automatically prevents the pipe from retracting by the pressure contact mechanism of the fixture, and it is possible to reliably prevent the pipe from retracting due to frequent tightening work or forgetting to tighten it by the conventional method.

<Embodiment> An embodiment of the present invention will be described below in detail with reference to FIGS. 1, 2, 3, 4, 5, and 6.

Fixture 3 equipped with six wedge-shaped mechanisms in the circumferential direction behind the start stop wall 14 fixed to the retaining wall 17 in the start shaft.
Are connected to each other by a plurality of support frames 13 to form an annular body 1, and the annular body 1 is arranged so that the center line of the annular body 1 and the planned center line of the buried pipe 12 coincide with each other. It is installed by fixing it to the 14 at several places with the connecting member 4. The wedge 2 mounted on the fixture 3 of the annular body 1 is arranged so as to come into contact with the outer surfaces of the shield machine 15 and the pipe 12.

The mechanism of the fixture 3 part is shown in FIG. 3, FIG. 4, FIG.
To explain in more detail with reference to the figure, the shield machine 15 and the pipe 12
The wedge 2 that comes into contact with the wedge is composed of a wedge receiving stand 7 that is provided so as to face the wedge 2 and come into contact therewith, and the wedge 2 and the wedge receiving stand 7 are provided on both sides of the wedge 2 and the wedge receiving stand 7, respectively. A wedge pull-back spring 8 is provided to hold the contact, and a plurality of contact adjusting screws 6 are provided on the wedge receiving base 7 so that the wedge 2 is brought into contact with a pipe or the like via the wedge receiving base 7. It has a mechanism.

Now, description will be made regarding the operating condition of the pipe ditch retracting prevention device according to one embodiment of the present invention. The shield machine 15 and the pipe ditch 12 are the source push jacks (not shown) mounted behind the starting shaft.
Is propelled into the ground by the thrust of. At this time, the wedge 2 of the fixture 3 that is in contact with the pipe 12 moves forward as the pipe 12 advances, and maintains a small space between the wedge 12 and the pipe 12. Release the contact. For this reason, the mechanism in which the wedge 2 does not exert a restraining force on the pipe 12 and the shield machine 15 while the pipe 12 is moving forward. When one stroke of the original push jack is completed, the jack is reduced, a steel spacer for one stroke of the jack is inserted between the pipe 12 and the jack, and the jack is extended again to extend the pipe 12 and the shield machine. 15 will be promoted.

In the muddy water type shield method and earth pressure type shield method, the shield excavator 15 and the pipe 12 are constantly pushed back by the earth pressure and water pressure at the tip face, and when the original jack is reduced, the shield machine 15 and pipe The force supporting 12 is released, and the shield machine 15 and the pipe 12 try to retreat to the vertical shaft side. At this time, the wedges 2 of the respective fixtures 3 are pulled back by the wedge pull-back springs 8 and are in contact with the pipes 12 as the pipes 12 stop moving forward. When each of the wedges 2 comes into contact with the pipe 12, the wedges 2 that come into contact with the pipe 12 and the like move backward, but are blocked by the wedge action with the wedge receiving stand 7 that comes into contact with the wedge 2. Further, a pushing pressure is applied to the side of the pipe 12 to press the pipe 12 and the like to prevent the shield machine 15 and the pipe 12 from retreating.

In the present embodiment, the number of fixtures 3 is six, but
It is possible to increase or decrease according to the condition of the pipe 12, earth pressure, and water pressure.

<Effects of the Invention> According to the present invention, it is possible to automatically prevent the rearward movement of the conduit or the shield machine when the source push jack is contracted or the conduit is replaced, and it is frequently towed as in the prior art. There is no need to check the tool or get nervous, and labor saving and shortening of the construction period can be easily achieved.

[Brief description of drawings]

FIG. 1 is a front view of a pipe drain backward movement preventing device showing an embodiment of the present invention. FIG. 2 is a side view showing the device. FIG. 3 is a detailed explanatory view of the pipe retracting prevention device of the present invention. FIG. 4 is a supplementary sectional view of FIG. FIG. 5 is a detailed explanatory view of the wedge. FIG. 6 is a detailed explanatory view of the wedge cradle. FIG. 7 is an explanatory view showing a backward movement preventing method in the prior art. In the figure, 1 is a ring-shaped body. 2 is a wedge. 3 is a fixture. 4 is a connecting material. 5 is a holding plate. 6 is a contact adjustment screw. 7 is a wedge cradle. 8 is a wedge pullback spring. 9 is a contact adjusting spring. Ten
Is a support stand. 16 is a tow. 17 indicates a retaining wall.

Claims (1)

[Claims] 1. From a start pit installed on the front of the start pit,
Holds a wedge cradle that is provided so as to face and face a plurality of wedges that come into contact with the outer periphery of the shield machine and the pipe, in a device that prevents the use of the shield machine and the pipe to move backwards A pipe retreat characterized in that a fixture composed of wedge pull-back springs connected to each other is connected to each other by a plurality of supporting frames in a circumferential direction to form an annular body, and the annular body is fixed to a front start stop wall. Prevention device.