JP2005106259A - Sheath pipe for excavating underground hole - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheath pipe for excavating a underground hole, requiring no long working time for attaching the sheath pipe and shortening a construction period. <P>SOLUTION: This sheath pipe is inserted into the underground hole formed by an excavating body excavating underground, and has a split part arranged along a longitudinal direction, and an engagement part provided at least at one end and with which the excavating body is engaged. The excavating body is inserted in the inside of the sheath pipe through the split part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to the structure of a sheath pipe for excavation of underground holes, for example, in order to lay a supply pipe that is connected to a buried pipe buried underground such as gas, water and sewerage, and then divides the underground hole. In the non-open cutting method to be formed, when excavating the underground, the excavator is protected from the collapse of the wall surface of the formed underground hole, and when the apparatus for connecting the supply pipe and the supply pipe are fed It is related with the underground pipe for excavation of an underground hole used in order to guide.

  In order to connect the supply pipe to the main branch pipe buried underground such as gas and water and sewerage, it is normal to excavate the part where the supply pipe is laid from the ground and remove the earth and sand before proceeding. In addition, the excavation work from the ground is necessary, which not only increases the work amount, but also increases the construction period, which is uneconomical. In addition, the influence on the area by digging up roads cannot be ignored. As a method of solving this problem, there is a non-cutting method, and an example thereof is proposed in Patent Document 1 below.

  Patent Document 1 states that “a flexible excavation rod (excavated body in this application) is inserted into a flexible sheath tube, and the excavation rod and the sheath tube are launched into the soil from the customer side. `` During excavation, reach the main branch pipe buried under the ground, then pull out the excavation rod from the inside of the sheath pipe, insert the PE pipe into the sheath pipe and connect the tip of the PE pipe to the main branch pipe '', As the configuration of the sheath tube, “the sheath tube 6 is formed to have a predetermined length and has flexibility without causing buckling deformation, and an outer peripheral surface and an inner peripheral surface are provided at each end in the longitudinal direction. Are formed with a male screw and a female screw, and the extension length is set to a desired length by fastening these screws.

  In addition, in the following Patent Documents 2 and 3, the present applicant can form an underground hole having an arc-shaped portion. For example, even if there is an obstacle such as an existing pipe in the ground, this can be bypassed with the smallest possible bending radius. A drilling device for non-open cutting method is proposed.

When the present applicant tried variously to apply the sheath tube and examined variously, when using a sheath tube that is inserted in the excavated body and connected in the longitudinal direction as described in Patent Document 1 Requires a lot of work to connect a number of relatively short pipes that do not cause buckling deformation, and every time the pipes are connected, it takes a lot of time to attach and detach the excavator from the propulsion unit. There was a problem of inviting.
Japanese Patent Laid-Open No. 11-182736 JP 2000-154275 A JP 2001-173905 A

  Accordingly, an object of the present invention is to provide a sheath pipe for excavation of underground holes that can reduce the construction period in the non-open-cutting method proposed by the present applicant and the like with less labor for attaching the sheath pipe. It is said.

  A sheathed pipe for excavating underground holes according to the present invention that solves such a problem in a sheathed pipe that is inserted into an underground hole formed by an excavating body that excavates the underground includes a divided part along its longitudinal direction, and at least one end thereof And an engaging portion with which the excavator is engaged. The excavated body is inserted into the sheath pipe through the divided portion. Therefore, even when the excavator is attached to, for example, a propulsion unit, the sheath pipe can insert the excavation unit into the inside through a divided portion formed along the longitudinal direction. It can be installed continuously without disconnecting. Moreover, since the sheath pipe is engaged with the excavation body at the engaging portion, it is inserted into the underground hole formed by the excavation body together with the excavation body.

  The engaging portion is preferably a structure that can maintain the engagement relationship when the excavator is propelled and that can be disengaged when the excavation body moves backward. If the engaging portion is configured in this way, the excavated body is recovered by pulling the excavated body back to the excavation start point, and the sheath tube remains inserted into the underground hole, making the excavated body extremely efficient. To be recovered.

  According to the present invention, it is possible to reduce the labor for attaching the sheath pipe, which is the subject of the present invention, and to shorten the construction period.

  The present invention will be described based on examples.

A first example of the present invention will be described with reference to FIGS.
FIG. 1 is a perspective view of a sheath tube used in the first example. FIG. 4 is a schematic view showing a laying state of a supply pipe that branches off from a main branch pipe already installed in the ground and extends to the house side on the ground. FIG. 5 is a diagram for explaining a state in which a pilot hole is excavated using the pilot hole excavation body. FIG. 6 is a diagram showing an engagement relationship between the excavated body that expands the pilot hole to form the underground hole and the sheath pipe of the first example. FIG. 7 is a view showing a state in which the sheath pipe of the first example is inserted into the underground hole along with the propulsion of the excavated body. FIG. 8 is a view showing a state in which formation of the underground hole and insertion of the sheath tube are completed. FIG. 9 is a view showing a state after the excavated body is pulled back to the ground and collected.

  In the first example, as shown in FIG. 4, a supply pipe 15 branched from the main branch pipe 6 buried under the road 5 and extending to the house side is laid. A PE pipe (polyethylene pipe) was used as the supply pipe 15, and one end thereof was connected to the main branch pipe 6 and the other end was connected to a meter vertical pipe 16 drawn into the house. As shown in the figure, the supply pipe 15 has a straight portion and an arc-shaped portion, and an underground hole is formed by a drilling device described in detail below according to the shape.

  As shown in FIGS. 5 and 7, the excavator 1 used in the first example is connected to the pilot hole excavation head 21 excavating the pilot hole and the pilot hole excavation head 21, and rotational force and thrust force are applied to the pilot hole excavation head 21. The drilling body 2 provided with a flexible drive means 22, a diameter-expanding bit 31 that is rotatable by the drive means 22, and the diameter-expanded bit 31 connected to the diameter-expanded bit 31. An excavation body (hereinafter referred to as a diameter-expanded excavation body) 3 provided with propulsion means 35 that transmits thrust and has flexibility, and the diameter-expansion excavation body 3 are inserted, and the diameter-expansion excavation body 3 and one end thereof are It has a sheath tube 81 to be engaged, and a propulsion device 4 that applies a rotational force and a thrust to the excavation head 21 and the diameter expansion bit 31. Hereinafter, the pilot hole excavation body 2, the diameter expansion excavation body 3, the sheath tube 81, and the propulsion device 4 will be described.

[Preliminary drilling body]
As shown in FIG. 7, an inclined surface 211 is formed on the excavation head 21 of the prepared hole excavation body 2 so that the tip side is sharp. Moreover, the drive means 22 can adjust the length of the pilot hole excavation body 2 easily by connecting a some rod member by screw fastening. Adjacent rod members have a structure that can swing around different axial directions in a direction orthogonal to the axial direction.

  According to the prepared hole excavation body 2, the straight portion and the arc-shaped portion are formed as follows. In the case of forming a straight line portion, a rotational force and a thrust force are applied to the excavation head 21 via the driving means 22. Since the inclined surface 211 of the excavation head 21 rotates, the direction of the propulsion reaction force received by the inclined surface 211 sequentially moves around the axis. Therefore, no bending occurs in the pilot hole excavation body 2, and the pilot hole excavation body 2 advances straight and forms a straight portion.

  For example, when forming an arcuate portion as shown in the figure, the inclined surface 211 is positioned downward, and the excavation head 21 is propelled without rotating. Then, since the inclined surface 211 receives a reaction force in one direction, the bending excavation body 2 is subjected to an upward bending moment. Therefore, the prepared hole excavation body 2 is bent to form an arcuate portion. The drive means 22 can also rotate while following the shape of the arcuate part. Therefore, if the excavation head 21 is rotated after forming the arcuate part, the pilot hole excavation body 2 goes straight and continues to the straight part following the arcuate part. Is formed.

[Expanded drilling body]
As shown in FIG. 6, the diameter expansion bit 31 has a non-rotating part 33 and a rotating part 34. The non-rotating part 33 and the rotating part 34 have a hole part through which the driving means 22 can penetrate at the center part. It is preferable that the hole of the rotating portion 34 is formed smaller than the excavation head 21 because the diameter-expanding bit 31 is also extracted simultaneously when the excavation head 21 is extracted from the ground.

  The rotating portion 34 is attached to the non-rotating portion 33 so as to be rotatable via a radial bearing 342. A plurality of diameter-enlarging blades 32 are provided at the front end of the rotating portion 34. When viewed from the front, for example, if the pin 321 is pivotably fixed so that the radius of rotation is larger than the outer diameter of the sheath tube 81 during the right rotation and smaller than the inner diameter of the sheath tube 81 during the reverse rotation. This is preferable because the diameter-expanding bit 31 can be pulled out through the pipe 81.

  The hole of the rotating part 34 is formed in a fitting shape capable of transmitting rotational force to the outer peripheral part of the driving means 22. The cross-sectional shape of the driving means 22 is basically a circle, but a groove or a flat portion along the axial direction is formed in order to transmit the rotational force to the diameter expanding bit 31. In the driving means 22 of the first example, two pairs of planes are formed on the outer peripheral portion. Therefore, a pair of planes is formed in the hole of the rotating portion 34 so that the driving means 22 is fitted. The size of the holes of the driving unit 22 and the rotating unit 34 is set such that the excavation bit 31 inserted in the driving unit 22 can slide in the axial direction.

  The propulsion means 35 is formed by assembling a plurality of propulsion members 36 having the same structure in a row along the drive means 22. The propulsion member 36 at the front end is connected to the non-rotating portion 33, and the propulsion member 36 at the rear end is a propulsion unit. Connected to the propulsion tool 42.

  The propelling member 36 is configured so that the driving means 22 can be held in the radial direction and connected, and the rotational force is not transmitted when the driving means 22 rotates. That is, the propulsion member 36 has, for example, a semicircular portion having an inner diameter larger than the outer diameter of the driving means 22 and a substantially U-shaped cross section having a wall portion formed of parallel extension line portions and one of which is open. To do. In addition, a protrusion having an arcuate tip is formed on one end surface of the propelling member 36 in the longitudinal direction, and an arcuate groove in which the protrusion is inserted is formed on the other end surface of the propelling member 36 at a boundary between the semicircular portion and the extension line portion. It is provided at the opposite position. Therefore, the projection of one propelling member 36 and the arc-shaped groove of another propelling member 36 can be fitted to each other to form a joint that can rotate around the arc-shaped groove. Therefore, the plurality of propulsion members 36 are connected at the nodes along the driving means 22.

  The non-rotating portion 33 is formed with an arc-shaped groove that fits with the protrusion of the propelling member 36 to form a joint. The propulsion tool 42 is formed with a projection having an arcuate shape that fits with the arcuate groove of the propelling member 36 to form a joint. A compressive force is applied between the adjacent propulsion members 36 or between the propulsion members 36 and the diameter-expanding bit 31 so that the joint does not come off. The compressive force is applied by, for example, an elastic member (rubber or the like) 364 locked to a pin 363 provided on the propelling member 36.

  In addition, a hook member 365 is attached to the joint of the propelling member 36 so as to hook the driving means 22 in the opposite direction to the propelling member 36, and the propulsion unit 36 is not lifted off from the driving means 22. What should I do? Note that the latch member 365, the pin 363, and the like are sized to fit inside the sheath tube 81.

  According to the diameter-extended excavated body 3, when the rotational force is applied via the driving means 22, the diameter-expanding bit 31 rotates, and when the thrust is applied via the propelling means 35, the diameter-expanding bit 31 is propelled along the driving means 22. Is done. Therefore, an underground hole is formed along the pilot hole formed by the driving means 22.

[Sheath tube]
A supply pipe 15 and a connection device for connecting the supply pipe 15 to the main branch pipe 6 and the like are supplied while the enlarged diameter excavation body 3 and the like are protected from the collapse of the wall surface of the underground hole formed by the enlarged diameter excavation body 3. As shown in FIG. 1, the sheath tube 81 to be guided is formed by a pair of divided portions 814 formed along the longitudinal direction thereof and arranged in a state facing each other on the outer peripheral surface, and the diameter-extended excavation body 3 is interpolated. And an engaging portion with which the diameter-extended excavation body 3 is engaged at least at one end. As shown in FIG. 6, the division part 814 is formed so that the diameter-extended excavation body 3 can be inserted into the internal passage 815.

The configuration of the sheath tube 81 will be specifically described. The sheath tube 81 is formed in a substantially semicircular cross section and can be combined into a substantially circular tube shape. The sheath tube 81 is fitted to one end of the combined circular tube member 811 and is engaged with the enlarged diameter bit 31. And an engaging member 813 which is a joint portion. Therefore, the division part 814 in the present embodiment is a part where the longitudinal end surfaces of the combined circular pipe members 811 are in contact.
According to the sheath tube 81, the diameter-extended excavation body 3 attached to the propulsion device 4 can be inserted into the internal passage 815. That is, the expanded diameter excavated body 3 is inserted into the internal passage 815 very simply by combining the circular pipe members 811 so as to sandwich the expanded diameter excavated body 3 to form the sheath tube 81. Since the enlarged diameter excavated body 3 and the sheath pipe 81 are engaged by the engaging member 813, the sheath pipe 81 is also drawn into the underground hole formed along with the propulsion of the enlarged diameter excavated body 3. Therefore, if the circular pipe member 811 is combined in accordance with the propulsion of the diameter-excavated body 3, the sheath pipe 81 is formed and pulled into the underground hole without interrupting the propulsion of the diameter-excavated body 3. Become.

  As the circular pipe member 811, a member substantially the same as or longer than the length of the underground hole is prepared. If the circular pipe member 811 is made of a relatively soft resin such as polyethylene, it is desirable that the sheath pipe 81 is flexible and can be bent. Furthermore, if the cross section along the longitudinal direction forms a corrugated shape as shown in the figure, the strength of the sheath tube 81 can be improved, and it is desirable that deformation is less when buried in the underground hole. Furthermore, it is desirable to use a so-called double-flexible tube having a corrugated outline in the longitudinal direction and a linear outline in the longitudinal direction inscribed in the outline, because the strength is further improved.

  Reference numeral 812 denotes a band-shaped close contact member that is tightened so that the combined circular tube member 811 does not separate. The close contact member 812 is not limited to the illustration, and may be brought into close contact with, for example, an engaging portion provided on the circular tube member 811 itself or screwing. Furthermore, since the circular tube member 811 is difficult to separate when inserted in a state where the sheath tube 81 is in close contact with the formed underground hole, the close contact member 812 is not necessarily required.

  As shown in FIG. 6, the engaging member 813 has a substantially cylindrical shape so that it can be fitted to one end of the combined circular pipe member 811. It is desirable that the engagement member 813 maintains the engagement relationship between the diameter-extended excavation body 3 and the sheath tube 81 when the diameter-expansion excavation body 3 is propelled, and releases the engagement relationship when the engagement is expanded. For example, the structure in which the tip of the non-rotating portion 33 of the diameter-expanding bit 31 abuts against the engaging member 813 or when the diameter-extended excavation body 3 is propelled, it stands up and falls when it is engaged with the engaging member 813 and retreats. What is necessary is just to set it as the structure using the key by which fitting is cancelled | released. With such a structure, when the diameter-extended excavator 3 is propelled, the sheath tube 81 is propelled together, and when retreating, only the diameter-excavated body 3 is pulled back to the ground, and the sheath tube 81 is an underground hole. It will be left in the state of being inserted into. As shown in the drawing, if the surface of the engaging member 813 against which the non-rotating portion 33 abuts has a shape in which the non-rotating portion 33 can be fitted, the arc-shaped portion can be prevented from being flattened and excavated. It is desirable that there is little opportunity for earth and sand or water to enter the inside of the sheath tube 81.

  In Example 1, since the outer diameter of the connection device of the supply pipe that is fed through the sheath pipe 81 after excavation of the underground hole is about 160 mm, the sheath pipe 81 is a soft material having an inner diameter of 165 mm and an outer diameter of 184 mm. A vinyl chloride pipe divided into two parts was used. A double flexible tube having an inner diameter of 200 mm and an outer diameter of 235 mm can be employed. In the case of this double flexible pipe, the minimum bending radius was about 1.2 m, and it was possible to propel it in an arc. Needless to say, if the dedicated cylindrical member 811 can be manufactured in accordance with the size of the connecting device to be fed, the excavation diameter can be minimized.

[Propulsion machine]
As shown in FIG. 7, the propulsion unit 4 is connected to a main body 43 arranged on the ground surface 5, guide means including a guide part 461 along the propulsion direction, and propulsion means 35, and the drive means 22 is pivoted. The propulsion tool 42 having an insertion portion that can penetrate in the center direction, the rotation means 411 to which the drive means 22 is connected, and the drive means 41 that reciprocates the rotation means 411 in the propulsion direction. The guide member is provided in the guide means so that the respective guide members are fitted in the common guide portion 461, and the propulsion device 42 can be moved simultaneously or independently with the drive portion 41 by the connecting tool 44.

The drive unit 41 includes a rotation unit 411 of the drive unit 22 and a guide member fitted to the guide unit 461. The rotating unit 411 applies a rotational force to the excavation head 21 and the diameter expanding bit 31 via the driving unit 22.
A propulsion device (not shown) is connected to the propulsion tool 42. The propulsion device propels the propulsion tool 42 and the drive unit 41 and applies thrust to the excavation head 21 and the diameter expansion bit 31. That is, the thrust of the propulsion device is transmitted to the excavation head 21 through the driving means 22 connected to the driving unit 41 via the rotating means 411 during excavation of the pilot hole, and the propulsion means 35 connected to the propulsion tool 42 during the diameter expansion excavation. Is transmitted to the diameter expanding bit 31 via the.

  By arranging the drive unit 41, the propulsion tool 42, and the propulsion means as described above, the excavation head 21 is driven when the pilot hole is excavated, and the excavation head 21 is driven when the pilot pipe is drawn by expanding the diameter of the pilot hole. It becomes possible to propel the diameter-expanding bit 31 fitted to the means 22. That is, when excavating the pilot hole, the propulsion tool 42 disposed in front and the drive unit 41 are coupled with each other by the connecting tool 44 so that the drive unit 41 is advanced by the propulsion means, and the excavation head 21 is driven. Promote When expanding the pilot hole and digging the sheath pipe, the drive unit 41 is lowered to the retracted end, the connecting tool 44 is detached from the propulsion tool 42 and coupled to the fixed side of the propulsion device, and only the propulsion tool 42 can be propelled. Like that. The thrust acts on the diameter-expanding bit 31 via the propulsion means 35 and propels the diameter-expanding bit 31.

  A method of forming an underground hole with the excavator 1 and laying the sheath tube 81 inserted into the underground hole will be described below.

[Preliminary drilling process]
As shown in FIG. 4, the propulsion device 4 is installed with a pile or the like at the excavation start point on the ground surface 5 on the side where the supply pipe 15 is drawn.

  The driving means 22 is prepared by assembling a number of rod members corresponding to the amount by which the propulsion tool 42 of the propulsion unit 4 moves by one stroke. The drive means 22 is connected to the excavation head 21 to assemble the prepared hole excavation body 2. The rear end of the driving means 22 is connected to the rotating means 411 of the propulsion device 4. The drive unit 41 of the propulsion device is coupled to the propulsion tool 42 by the connecting tool 44. The inclination of the propulsion unit 4 is adjusted so that the pilot hole excavation body 2 can enter the ground at a predetermined entry angle.

  The pilot hole excavation body 2 is advanced into the ground, and the excavation head 21 is propelled. When the drive unit 41 is pushed to the stroke end, the drive unit 22 and the rotation unit 411 are disconnected and the drive unit 41 is moved backward. The new drive means 22 prepared in the same manner as described above is connected to the rear portion of the drive means 22 already inserted into the ground, and the rear end of the new drive means 22 is connected to the rotation means 411. Thereafter, the propulsion operation is repeated until the main branch pipe 6 is reached while correcting the direction of the excavation head 21.

  Here, when there is an obstacle on the way to the main branch 6, the excavation head 21 is appropriately detoured. The position, posture, and direction of the inclined surface 211 necessary for guiding the excavation head 21 are detected by, for example, incorporating a sonde (not shown) that emits electromagnetic waves into the excavation head 21 and measuring the magnetic field with a receiving device. Can do.

[Underground drilling process]
Next, the diameter of the pilot hole is expanded to form an underground hole, and the sheath tube 81 is drawn into the underground hole.
A circular pipe member 811 and an engagement member 813 having a predetermined length are prepared.
As shown in FIG. 7, after the pilot hole excavation process is completed, the drive unit 41 of the propulsion device 4 is retracted and fixed to the rear end of the propulsion device 4. Disconnect the drive means 22 and the rotation means 411. The front end portions of the circular pipe members 811 are combined so as to sandwich the driving means 22, and the engaging member 813 is fitted to the front ends of the combined circular pipe members 811. The driving means 22 is passed through the hole of the diameter expanding bit 31, the diameter expanding bit 31 is engaged with the engaging member 813, and the driving means 22 and the rotating means 411 are connected.

  The number of propulsion members 36 corresponding to the amount by which the propulsion tool 42 of the propulsion device 4 moves by one stroke is assembled along the drive means 22 while being connected to each other. Here, the propelling member 36 on the diameter expanding bit 31 side is connected to the non-rotating part 33 of the diameter expanding bit 31, and the propelling member 36 on the propulsion machine 4 side is connected to the propelling part 42.

  The expanded drilling body 3 is started into the ground. The rotating force of the rotating means 411 is transmitted to the diameter expanding bit 31 via the driving means 22, and the thrust of the propulsion device is transmitted via the propelling means 35. Since the driving means 22 is inserted into the hole portion of the diameter-expanding bit 31, the diameter-expanding bit 31 expands the pilot hole while being propelled along the driving means 22, and forms an underground hole. At this time, the sheath tube 81 engaged with the diameter-extended excavation body 3 by the engaging member 813 is drawn into the underground hole with the propulsion of the diameter-expanding bit 31.

  After the propulsion tool 42 has moved one stroke, the propulsion tool 42 is pulled back. Thereafter, as shown in FIG. 8, if the above operation is repeated until the diameter-expanding bit 31 reaches the excavation head 21, a underground hole having a predetermined length is formed and the sheath tube 81 is formed over the entire length of the underground hole. Is pulled in and inserted. Thereafter, the diameter-expanding bit 31 and the excavation head 21 are recovered through, for example, a resist formed at the connection site of the main branch pipe 6, and the driving unit 22 and the propulsion unit 35 are pulled back and collected by the propulsion unit 4.

  The propulsion unit 4 can be driven by the propulsion unit 4 if the above-mentioned preferred engagement portion, that is, the engagement portion is maintained when the expanded diameter excavation body 3 is propelled and the engagement relationship is released when retreating. By pulling back, the expanded-diameter excavated body 3 is recovered, and the sheath tube 81 remains in a state of being inserted into the underground hole, which is preferable because there is no time for excavating the resist. Further, if the hole portion of the rotating portion 34 of the diameter expanding bit 31 is made smaller than the size of the excavation head 21, the diameter expanding excavation body 3 and the lower hole excavation body 2 can be simultaneously operated by pulling back the driving means 22 with the propulsion device 4. Since it can collect | recover, it is preferable.

A sheath tube 82 of a second example according to the present invention will be described with reference to FIG. The laying method of the sheath tube 82 of the second example is basically the same as that of the sheath tube 81 of the first example.
The sheath tube 82 is disposed at least at one end, an internal passage 815 in which the enlarged-diameter excavator 3 is inserted, a split portion 824 that is formed along the longitudinal direction and can insert the enlarged excavator 3 into the internal passage 815. The enlarged diameter excavated body 3 has an engaging portion.

The configuration of the sheath tube 82 will be specifically described. The sheath tube 82 includes a cylindrical member 821 whose side surfaces are cut along the longitudinal direction and can be combined into a substantially circular tube shape, and an engaging member 813 similar to the above as an engaging portion. Therefore, the dividing portion 824 in the second example is a portion where the cut end surface of the cylindrical member 821 is brought into contact. For the sheath tube 82, a contact member 812 similar to the above can be employed as necessary.
According to the sheath tube 82, basically the same effect as the sheath tube 81 of the first example can be obtained.

A third example of the sheath tube 83 according to the present invention will be described with reference to FIG. The laying method of the sheath tube 82 of the second example is basically the same as that of the sheath tube 81 of the first example.
The sheath tube 83 of the present embodiment includes an internal passage 815 in which the above-mentioned enlarged-diameter excavation body 3 is inserted, a split portion 834 that is formed along the longitudinal direction and can insert the enlarged-excavation body 3 into the internal passage 815, and a circle It has a division part 835 along the circumference, a connection member 836 arranged in the division part 835 along the circumference, and an engagement part arranged at least at one end and engaged with the enlarged-diameter excavation body 3.

  The configuration of the sheath tube 83 will be specifically described. The sheath tube 83 is shorter than the underground hole and has a substantially semicircular cross-section, and can be assembled into a substantially tubular shape. The sheath tube 83 is fitted into one end of the combined circular tube member 811 and is expanded. An engagement member 833 that is an engagement portion with which the diameter bit 31 engages, and the circular pipe member 831 combined in the longitudinal direction is connected by the connection member 836. Accordingly, the longitudinal division portion 834 in this embodiment is a portion where the length of the combined circular tube member 831 is in contact, and the division portion 835 along the circumference is in contact with the end surface of the combined circular tube member 831. Part.

  As shown in the figure, the engaging member 833 has a pair of semicircular first members 833a and a second annular member 833b, and the first member 833a and the second member 833b are formed in combination. The connecting member 836 is, for example, a belt-shaped member obtained by sheet metal molding of a thin plate, and can be easily connected to the cylindrical member 831 in the longitudinal direction by being manually wound around the divided portion 835 along the circumference.

  According to the sheath tube 83, since the length of the cylindrical member 831 can be shortened compared to the sheath tubes 81 and 82 of the first example and the second example, handling becomes convenient. Furthermore, if the cylindrical member 831 having a length divided into the length of the underground hole is used, the divided portion 835 along the circumference becomes a node, and the sheath tube 83 has flexibility. Therefore, even when the rigid cylindrical member 831 is employed as compared with the cylindrical members 811 and 812 of the first example and the second example, the sheath tube 83 can be inserted along the underground hole, and the deformation of the sheath tube 83 is less preferable. .

  The present invention can be applied not only to laying supply pipes for gas and water and sewage but also to excavating relatively long underground holes, for example, for laying work of electric wires and optical cables.

It is a perspective view which shows an example of the sheath pipe of this invention. It is a perspective view which shows an example of the sheath pipe of this invention. It is a perspective view which shows an example of the sheath pipe of this invention. It is a schematic diagram of the supply pipe branched from this branch pipe and laid in the house side It is a figure which shows an example of the hole excavation using a pilot hole excavation body. It is sectional drawing which shows the diameter expansion bit and sheath pipe of a diameter expansion excavation body. It is a side view which shows the middle state of a casing pipe drawing diameter expansion excavation. It is a side view which shows the completion state of a casing pipe drawing diameter expansion excavation. It is a side view containing the partial cross section of the sheath pipe embed | buried in the ground.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drilling device 2 Pilot hole drilling body, 21 Drilling head, 22 Rod unit 3 Diameter expansion drilling body, 31 Diameter expansion bit, 35 Propulsion unit 4 Propulsion machine, 41 Drive part, 42 Diameter expansion bit propulsion part 5 Ground surface 6 This branch pipe 8 (17) Sheath tube 9 Integrated sheath tube tip 10 Sheath tube tip 11 Sheath tube fastening band 12 Connecting bracket 18 Sheath tube unit

Claims (2)

  A sheath tube inserted into an underground hole formed by an excavating body excavating in the ground, having a divided portion along the longitudinal direction, and an engaging portion with which the excavating body is engaged at least at one end The excavated body is inserted into the sheath pipe through the divided portion, and the underground pipe for excavating underground holes is provided.   The shell tube for underground excavation according to claim 1, wherein the engagement portion maintains an engagement relationship when the excavation body is propelled and an engagement relationship is released when the excavation body moves backward. A sheath pipe for excavating underground holes.

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