JP3845743B2 - Preventing face collapse - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for preventing collapse of a face of a tip of a leading conductor in a propulsion method for propulsion embedding a small diameter steel pipe.
[0002]
[Prior art]
The conventional method of propelling and embedding small-diameter pipes has a relatively short propulsion extension, so it does not require a direction correction device, etc., and a compact excavator makes it possible to carry out propulsion from a small start shaft. It is possible. As the pipe material, a steel pipe manufactured to a length that can be installed in the start shaft is mainly used. The excavator installed in the start shaft has a structure in which a drive device mounted on a guide frame can be moved forward and backward by a cylinder device. The steel pipe chuck portion of the drive device grasps the outer periphery of the rear end of the steel pipe, drives the excavation device, and transmits the rotation to the steel pipe via the steel pipe chuck portion. At the tip of the steel pipe, a tip conductor equipped with a drilling tip is installed on the outer periphery, the steel pipe is advanced while applying a rotational force to the steel pipe by the steel pipe chuck part of the driving device, and the ground is cut by the drilling tip at the tip, In this method, steel pipes are buried while taking excavated earth and sand into the steel pipes.
[0003]
[Problems to be solved by the invention]
The propulsion method for propelling and embedding a small-diameter steel pipe enables efficient construction of the propulsion embedding of the steel pipe from the small-diameter start shaft. However, in the case of ground with soft soil conditions or ground with a lot of groundwater, the tip end conductor 14 is open as shown in FIG. It flows into the leading conductor 14 together with the groundwater, and a cavity 16 is formed outside the steel pipe 11, causing ground subsidence.
[0004]
Therefore, in the case of soft ground or ground with a lot of groundwater, an auxiliary construction method has been adopted in which the ground is improved by injecting a chemical solution into the place where the steel pipe is buried, so that the ground at the face part becomes independent. However, the above-mentioned auxiliary method by injecting chemicals makes it difficult for the chemicals to penetrate between the soil particles in soft ground, and in the ground with a lot of groundwater, the chemicals are flowed or diluted before hardening, so it is difficult to expect the effect. There was a problem.
[0005]
For this reason, the present invention provides a method for preventing collapse of the face ground at the tip of the opened leading conductor in a propulsion method for propelling and embedding a small-diameter steel pipe.
[0006]
[Means for Solving the Problems]
That is, the present invention is equipped with a cutting tool on the outer periphery of the leading conductor of the tip, and prevents the face of the tip of the leading conductor from collapsing during the propulsion work in order to propel and embed a small diameter steel pipe while cutting the ground. In the method
A water-stop device comprising a water-stop ring attached to the outer shell of a cylindrical body smaller than the inner diameter of the steel pipe so as to abut the inner surface of the steel pipe, and a plate fixed so as to close the cylindrical body, Installed on the inner surface of the rear end and injected muddy water into the steel pipe from the water stop device to fill the steel pipe with mud pressure to create a small diameter steel pipe while resisting face pressure and water pressure. This is a method to prevent the face from collapsing by carrying out propulsion work with the excavator installed inside.
[0007]
The water stop device is manufactured to a predetermined length in the propulsion direction with a cylindrical body smaller than the inner diameter of the steel pipe. A water stop ring made of a rubber material having a predetermined height is attached to the outer shell of the cylindrical body along the outer periphery of the steel pipe so as to contact the inner surface of the steel pipe. The water-stop ring can be made to contact the inner surface of the steel pipe by sending compressed air or the like with the inside of the ring as a cavity. A plate is fixed to one of the front and rear of the cylinder by welding or the like so as to close the cylinder. The plate is provided with an injection hole for injecting muddy water into the steel pipe and a discharge hole for discharging muddy water and excavated soil.
[0008]
The digging machine has a mechanism in which a drive device mounted on a guide frame is moved forward and backward by a cylinder device. The outer periphery of the steel pipe is grasped by the steel pipe chuck portion of the driving device. By driving the drive device, the steel pipe chuck portion rotates, and the rotational force is transmitted to the steel pipe. The drive device is mounted on the guide frame and can be moved forward and backward by a cylinder device mounted on the guide frame.
[0009]
The leading conductor forms a cylindrical body having the same diameter as the outer diameter of the steel pipe, and is attached to the leading portion of the steel pipe by welding or the like. A hard excavation tip is embedded to cut the face ground at the tip of the leading conductor.
[0010]
A water stop device is installed on the inner peripheral surface of the rear end of the steel pipe, and muddy water is injected from an injection hole provided in the plate to fill the steel pipe with muddy water. The muddy water is sealed by the water-stop ring of the water-stop device and does not leak backward, and the muddy water pressure is maintained in the front steel pipe to prevent the face ground from collapsing. By driving the driving device to rotate the steel pipe chuck portion, the steel pipe is propelled while cutting the ground with the excavation tip of the tip conductor. At this time, efficient propulsion work can be performed by sending mud from the injection hole and discharging it from the discharge hole for circulation. When the propulsion construction of one steel pipe is completed, the drive device of the excavator is moved backward, the next steel pipe is installed in the space, and the rear end face of the previous steel pipe is joined. When the joining is completed, the water stop device installed inside the rear end of the previous steel pipe is pulled back by the pulling means to the rear end of the newly connected steel pipe. When the installation of the water stop device is completed, the drive device is driven and the propulsion work is resumed.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plan view for explaining a method for preventing face collapse according to the present invention. The excavator 1 is installed in the circular start shaft 12. The structure of the excavator 1 is such that the guide frame 4 is assembled so that the steel pipe 11 to be propelled and buried is in the planned embedding position, and the drive device 2 including the steel pipe chuck portion 3 is mounted on the guide frame 4. The drive device 2 is connected to a cylinder device (not shown) so that the drive device 2 can move back and forth on the guide frame 4. The front of the drive device 2 has an outer periphery of the end of the steel pipe 11. It is equipped with a steel pipe chuck portion 3 for grasping the above, and has a mechanism for transmitting the rotation by the driving device 2 to the steel pipe 11.
[0012]
A water stop device 5 is installed inside the rear end of the steel pipe 11. The structure of the water stop device 5 is such that a water stop ring 7 is provided on the outer periphery of the cylindrical body 6 smaller than the inner diameter of the steel pipe 11 so as to abut on the inner surface of the steel pipe 11, A plate 8 is fixed on either side.
The plate 8 is provided with an injection hole 9 for sending mud and a discharge hole 10 for discharging mud and excavated soil. A gate valve is provided in the injection hole 9 and the discharge hole 10. At the rear end of the water stop device 5, an expansion / contraction jack which is a pull-back means 13 provided in the excavator 1 is connected so that the steel pipe 11 can be moved forward and backward.
[0013]
The water-stop ring 7 may have a ring shape made of a rubber material having a predetermined height so as to abut against the inner surface of the steel pipe 11. A contact method can also be used. Although a telescopic jack has been disclosed as the pullback means 13, other pullback techniques according to the prior art can also be used.
[0014]
FIG. 2 is a plan view for explaining a method of installing a steel pipe when one steel pipe propulsion is completed. When the propulsion construction of one steel pipe 11 is completed, the water stop device 5 and the extension jack are disconnected, and the extension jack is reduced. Moreover, the steel pipe 11 of the steel pipe chuck part 3 is also opened and returned to the rear together with the driving device 2 by the cylinder device. The next steel pipe 11 is suspended in the space formed between the rear end of the previous steel pipe 11 and the driving device 2 and installed on the guide frame 4. When the installation is completed, the rear end of the steel pipe 11 is grasped by the steel pipe chuck portion 3, the steel pipe 11 is advanced by the driving device 2, and the butt joint portion is joined to the front steel pipe 11 by welding.
[0015]
When contracting the telescopic jack as the pull-back means 13, since the pull-back force by the muddy water is acting on the water stop device 5, a stopper is attached to the end surface of the steel pipe 11 in advance to prevent the water stop device from returning. .
[0016]
FIG. 3 is a plan view for explaining the moving method of the water stop device of the present invention. When the joining of the steel pipe 11 is finished, the extension jack is extended to connect the head of the extension jack to the rear end of the water stop device 5. When the connection is completed, the telescopic jack is reduced and the water stop device 5 is moved backward while sliding in the steel pipe 11. At this time, since the volume in the steel pipe 11 in front of the water stop device 5 changes, the muddy water is injected from the injection hole 9 and the steel pipe 11 is filled with the muddy water and moved. When the water stop device 5 moves to the rear of the last steel pipe 11, the propulsion construction of the steel pipe 11 is resumed.
[0017]
【The invention's effect】
As described above, the method for preventing face collapse according to the present invention is such that the steel pipe is filled with muddy water, and the muddy water pressure is constantly acting on the face of the tip of the leading conductor, so that soft ground and groundwater Even in a lot of ground, mud pressure suppresses natural ground and groundwater, so that the collapse of the face can be surely prevented, and the steel pipe can be propelled safely with a small diameter.
[0018]
[Brief description of the drawings]
FIG. 1 is a plan view for explaining a method for preventing face collapse according to the present invention.
FIG. 2 is a plan view for explaining a method of installing a steel pipe when one steel pipe propulsion is completed.
FIG. 3 is a plan view for explaining a moving method of the water stop device of the present invention.
FIG. 4 is a vertical cross-sectional view for explaining a face situation in conventional small diameter steel pipe propulsion construction.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Excavator 2 Drive apparatus 3 Steel pipe chuck part 4 Guide frame 5 Water stop apparatus 6 Cylindrical body 7 Water stop ring 8 Plate 9 Injection hole 10 Discharge hole 11 Steel pipe 12 Starting shaft 13 Pull back means 14 Lead conductor 15 Excavation tip 16 Cavity

Claims (1)

In the method of preventing the tip of the tip of the leading conductor from collapsing during propulsion work, in order to embed a cutting tool around the tip of the leading conductor and embed a small diameter steel pipe while cutting the ground,
A water-stop device comprising a water-stop ring attached to the outer shell of a cylindrical body smaller than the inner diameter of the steel pipe so as to abut the inner surface of the steel pipe, and a plate fixed so as to close the cylindrical body, Installed on the inner surface of the rear end and injected muddy water into the steel pipe from the water stop device to fill the steel pipe with mud pressure to create a small diameter steel pipe while resisting face pressure and water pressure. A face collapsing prevention method characterized in that propulsion work is performed by an excavator installed inside.

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