Adit excavation method and pipe laying method

Abstract

To provide a construction method capable of safely, stably, and quickly performing adit excavation, pipe laying, and the like.SOLUTION: By excavating the ground using an excavator 61, the ground between a starting shaft 12 and an arrival shaft 13 is excavated in the underground horizontal direction to form an adit 14 extending from the starting shaft 12 side to the arrival shaft 13 side through the ground. A propulsion pipe 21 is pushed into the adit 14, and the propulsion pipe 21 is laid over the entire length of the adit 14 by the push-in intervention. The propulsion pipe 21 laid in the adit 14 is removed out of the adit 14.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] One aspect of the present invention relates to an adit excavation method that can be effectively used in various ground construction fields, including civil engineering (including agricultural civil engineering).

[0002] Another aspect of the present invention relates to a pipe installation method capable of economically and rationally installing a composite pipe consisting of a drain pipe and a protective pipe in an adit.

[0003] Yet another aspect of the present invention relates to a pipe laying method capable of laying a drain pipe in an adit safely, stably and quickly. [Background technology]

[0004] As is well known, the groundwater level lowering method, which belongs to the field of civil engineering, is said to be as follows. One of them is that it forcibly lowers the groundwater level in residential areas and roads to reduce damage caused by liquefaction, and also reduces the possibility of liquefaction occurring and limits damage caused by liquefaction by making several meters below the ground surface into a non-liquefaction layer. The other is that it applies to both roads and residential land, so it fits easily into the framework of integrated liquefaction countermeasures for public facilities and residential land.

[0005] Regarding the drain pipe method, which is one of the groundwater level lowering methods, in this method, a porous drain pipe with water permeability is buried in a specified section of the ground under construction, approximately horizontally or at a gentle slope. The drain pipe (also called a drain pipe) buried in the ground collects and drains rainwater and spring water from the ground, lowering the groundwater level of the target ground to the required level. Therefore, the ground after construction using this method is less likely to liquefy.

[0006] The following Patent Documents 1 to 8 are known as technical documents relating to the above-mentioned drain pipes and their installation. Of these, the technologies in Patent Documents 1 to 6 have issues, which are resolved by the technology in Patent Document 7. On the other hand, Patent Document 8 points out that the technology in Patent Document 7 also has issues, which are resolved by the technology in Patent Document 8. Therefore, of the technologies disclosed in Patent Documents 1 to 8, the technology disclosed in Patent Document 8 can be said to be the more advanced technology.

[0007] Regarding the drain pipe installation method disclosed in Patent Document 8, when the contents of the document are referred to, it is noted that the document describes effects such as safety of installation, accuracy of installation, ease of construction, shortening of installation period, reduction of installation labor, reduction of installation costs, reduction of installation costs and shortening of construction period, secure placement of drain pipes in adit tunnels, improvement of ease of laying composite pipes in adit tunnels, reduction of installation costs and shortening of construction period, etc.

[0008] However, Patent Document 8 does not disclose any technical solution to the technical problems required for economically and rationally excavating a high-precision adit. Of course, in such construction, simply excavating an adit using an excavator is not enough to create a high-precision, good adit. Therefore, there is a demand for an adit excavation technology that can solve such problems and achieve the desired purpose.

[0009] However, if the only focus is on improving the accuracy of the adit, it may seem like it would be better to combine multiple excavation processes, such as rough excavation in advance, semi-finishing excavation in the middle, and high-accuracy excavation in the latter. However, in the case of an excavation method that requires so many processes, it is impossible to avoid significant delays in construction time and huge construction costs due to the increase in the number of processes. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2008-144558 A [Patent Document 2] JP 2004-100185 A [Patent Document 3] JP 2002-364785 A [Patent Document 4] JP 2002-275876 A [Patent Document 5] JP 2001-055719 A [Patent Document 6] JP 2007-064457 A [Patent Document 7] JP 2017-002641 A [Patent Document 8] JP 2020-033714 A Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention has been made in consideration of the above-mentioned problems, and has as its object to provide a useful and beneficial construction method which can satisfy the above requirements, such as digging an adit between a starting shaft and a destination shaft, laying a composite pipe in the adit, and laying a drain pipe in the adit, by carrying out the required construction work more safely, accurately, easily, highly precisely, economically, and rationally, and by shortening the construction period. [Means for solving the problem]

[0012] The present invention relates to an adit excavation method, which comprises the following steps 1 to 4 as means for solving problems to achieve the intended purpose: Section 7 The present invention is characterized by the technical content described in the above. <Section 1> By excavating the ground using an excavator, the ground between the starting shaft and the arrival shaft is excavated in the horizontal direction underground to form a horizontal tunnel extending from the starting shaft side to the arrival shaft side; and Pushing a jacking pipe into the adit and laying the jacking pipe over the entire length of the adit by pushing and intervening; and Removing the thrust pipe laid in the adit to the outside of the adit; and The adit is inserted through the adit multiple times over its entire length until the adit is free of undesirable roughness, irregularities, or steps on its inner diameter or inner peripheral surface. This is an adit excavation method characterized by the above. <Section 2> 2. An adit excavation method as described in claim 1, in which the adit excavation pipe laid in the adit is removed from the adit by pushing or pulling out the adit pipe from one end of the adit toward the arrival shaft. <Section 3> The method according to claim 1, wherein a slipping member is interposed between the outer peripheral surface of the thrust pipe and the inner peripheral surface of the adit when the thrust pipe is pushed into the adit and when the thrust pipe is removed from the adit, or when both of these are performed. or Term 2 An adit excavation method described in any of the above. <Section 4> Item 1, in which the thrust pipe is laid in the adit while the adit is being excavated. or item 3 An adit excavation method described in any of the above. <Section 5> The thrust pipe laid in the adit is axially extended through a tubular connecting fitting. The joint is designed to form a continuous tube with no steps on the inner or outer periphery. The above paragraph 1 which is connected or item 4 An adit excavation method described in any of the above. <Section 6> 6. An adit excavation method as described in claim 5, wherein the connecting connector is freely attachable to and detachable from the thrust pipe. <Section 7> 7. The horizontal shaft excavation method according to any one of claims 1 to 6, in which the ground between the starting shaft and the arrival shaft is excavated horizontally underground from the starting shaft side to the arrival shaft side.

[0013] The pipe laying method according to the present invention has the following features as a means for solving problems in order to achieve the intended purpose. Sections 8 to 12 The present invention is characterized by the technical content described in the above. <Section 8> By excavating the ground using an excavator, the ground between the starting shaft and the arrival shaft is excavated in the horizontal direction underground to form a horizontal tunnel extending from the starting shaft side to the arrival shaft side; and Pushing a jacking pipe into the adit and laying the jacking pipe over the entire length of the adit by pushing and intervening; and Removing the thrust pipe laid in the adit to the outside of the adit; and The adit is inserted into the adit several times over its entire length until the adit is free of undesirable roughness, irregularities, and steps on its inner diameter and inner peripheral surface; and Laying a composite pipe having a drain pipe located relatively inside and a protective pipe located relatively outside over the entire length of the adit A pipe laying method characterized by the above. <Section 9> By excavating the ground using an excavator, the ground between the starting shaft and the arrival shaft is excavated in the horizontal direction underground to form a horizontal tunnel extending from the starting shaft side to the arrival shaft side; and Pushing a jacking pipe into the adit while excavating the adit, and laying the jacking pipe over the entire length of the adit by pushing the jacking pipe into the adit; and Removing the thrust pipe laid in the adit to the outside of the adit; and The adit is inserted into the adit several times over its entire length until the adit is free of undesirable roughness, irregularities, and steps on its inner diameter and inner peripheral surface; and Laying a composite pipe having a drain pipe located relatively inside and a protective pipe located relatively outside over the entire length of the adit; and By removing the protective pipe from the composite pipe laid in the adit to the outside of the adit, the drain pipe is left in the adit and laid over the entire length of the adit. A pipe laying method characterized by the above. <Section 10> The thrust pipe laid in the adit is pushed or pulled out from one end of the adit to the arrival shaft side, thereby removing the thrust pipe from the adit. Section 8 or 9 A pipe laying method described in any of the following. <Section 11> Either when the thrust pipe is pushed into the adit and inserted, or when the thrust pipe is removed from the adit Or both In the above, a sliding material is interposed between the outer peripheral surface of the thrust pipe and the inner peripheral surface of the adit. Sections 8 to 10 A pipe laying method described in any of the following. <Section 12> The thrust pipe is laid in the adit while the adit is being excavated. Paragraphs 8 to 11 A pipe laying method described in any of the following. Effect of the Invention

[0014] [Effects of the horizontal tunnel excavation method] The adit excavation method according to the present invention has the following advantages (01) to (09). (01) In the conventional adit excavation method, a certain part of the stratum is simply scraped off with an excavator. In such a conventional method, the finished state of the inner circumferential surface (surface surface) of the adit is extremely rough (rough). In contrast, in the case of the method of the present invention, in which the adit is excavated while the jacking pipe is pushed into the adit, the jacking pipe functions as an ideal prototype for the adit, so the adit is also finished in an ideal shape that follows the outer shape of the jacking pipe. In particular, in the case of the method of the present invention, not only a part of the stratum is scraped off to form the adit, but the inner circumferential surface of the adit is rubbed with the outer circumferential surface of the jacking pipe in synchronization with the excavation, so that the inner circumferential surface of the adit is finished as if it had been trowel-finished with the smooth outer circumferential surface of the jacking pipe. The adit that is finished in this way is highly accurate, with no undesirable roughness, unevenness, or steps on its inner diameter or inner surface. (02) In general, the thrust pipe is pushed into the adit over its entire length, and then pushed out of the adit and removed. When the thrust pipe is removed out of the adit by pushing it in this way, a compressive force in the axial direction acts on the thrust pipe from start to finish, and the thrust pipe continues to receive the compressive force. Even if the thrust pipe does not break due to this, the thrust pipe that is constantly receiving a specific load (compressive load) tends to have residual stress, which is undesirable. In contrast, in the adit excavation method according to the present invention, for example, the thrust pipe is pushed into the adit over its entire length, and then the thrust pipe is pulled out of the adit and removed. The thrust pipe handled in this way cancels both the stresses of pushing in and pulling out, so that the thrust pipe is unlikely to have any problems such as residual accumulation of stress. If the thrust pipe is handled well in this way, it will be able to withstand repeated use and long-term use of the thrust pipe will be realized. (03) In the adit excavation method according to the present invention, when the thrust pipe is pulled out from inside the adit and removed, an intermediate (relay) device such as a thrust device used for pushing and removing the pipe is not required. By eliminating this intermediate device, the labor and costs involved in carrying out this adit excavation method can be significantly reduced. (04) In the case of the adit excavation method of the present invention, the adit excavation work and the work of laying the thrust pipe into the adit are synchronized, and the two works are carried out together without any time lag, thereby shortening the time required for the process, making it possible to construct an adit that is highly efficient, economical, and rational. (05) In the case of the adit excavation method according to the present invention, as described above, the adit is formed with extremely high precision, including its inner periphery. The pipe laying and removal that are carried out after the adit is formed does not involve excessive work load, as the pipe is simply pushed into the adit or pulled out. Therefore, the pipe to be laid can be laid safely, stably, and with little load, relying on the highly accurate adit. (06) In the case of the adit excavation method according to the present invention, the jacking pipe after being removed from the adit can be reused (reused and recycled) as described above. When such reuse is possible, the cost required for tools and equipment for adit excavation is reduced, which in turn contributes to the economical and rational construction of adits. (07) In the adit excavation method according to the present invention, when the work of pushing the pipe into the adit (advancing work) and the work of pulling the pipe out of the adit (removal work) are carried out in one of the shafts, such as the starting shaft, the machinery (work equipment) such as hydraulic jacks can be used for both of these tasks (pushing the pipe in and pulling the pipe out). This reduces the burden on the equipment required for laying and removing the pipe. (08) When the adit excavation method of the present invention connects the thrust pipes to each other, the stability of the row of thrust pipes is improved, and the thrust pipes in the connected state can be pushed out and pulled out more reliably. (09) Regarding the above-mentioned work of connecting (connecting) the propulsion pipes to each other, in the case of indirect connection, in which the propulsion pipes are connected to each other in the axial direction via a tubular connector (small and light), it is a simple and light work with less load than direct connection of the propulsion pipes to each other. This is because the work can be performed mainly using the connector, which is much smaller than the propulsion pipes, while the work of moving the propulsion pipes, which are heavier than the connector, is greatly reduced.

[0015] [Effects of composite pipe laying method] The composite pipe installation method according to the present invention has the above-mentioned effects (01) to (09) as well as the following effects (10) to (11). (10) The composite pipe laying method according to the present invention has the above-mentioned effects (01) to (09), and therefore the composite pipe can be laid in an adit safely, stably, smoothly, easily and with a small load. (11) The composite pipe used in the composite pipe laying method according to the present invention is one in which a drain pipe is installed inside a protective pipe. In this case, the drain pipe is made of a porous pipe structure with water permeability, which is a weak point in terms of strength. However, the protective pipe exteriorly covering the drain pipe ensures the strength of the drain pipe in terms of its fragility (lack of strength). In other words, in the case of a composite pipe, the combined strength of the drain pipe and the protective pipe provides a strength that exceeds that of a single pipe, and the protective pipe on the outside protects the inner drain pipe from external forces. Therefore, in the case of a composite pipe, it is almost impossible for the vital drain pipe to be broken, damaged, or destroyed due to an accident or other reasons.

[0016] [Effects of drain pipe installation method] The drain pipe installation method according to the present invention has the following effects (12) to (13). (12) The drain pipe installation method according to the present invention also includes all the steps of the composite pipe installation method described above, and therefore has all the same effects as the effects (01) to (11) described above. (13) The drain pipe installation method according to the present invention also has the above-mentioned effects (01) to (11), and therefore, based on these, the drain pipe can be laid in the adit safely, stably, easily, smoothly, quickly, and with little burden and effort. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a vertical cross-sectional view showing one embodiment of an adit excavation method according to the present invention. [Diagram 2] 1 is a perspective view showing one embodiment and another example of a thrust pipe used in an adit excavation method according to the present invention. FIG. [Diagram 3] FIG. 2 is a cutaway front view showing a representative example of a connecting connector between jacking pipes used in the pipe-laying method according to the present invention, cut in half. [Figure 4] 1 is a longitudinal cross-sectional view illustrating a composite pipe laying method according to one embodiment of the present invention; FIG. [Diagram 5] 1 is a front view of a main portion of an embodiment of a composite pipe used in a pipe-laying method according to the present invention, and a cross-sectional view of an embodiment of a support pipe. [Figure 6] FIG. 2 is a front view of a composite pipe used in the pipe-laying method according to the present invention, showing a part of the composite pipe in section. [Figure 7] 1 is a longitudinal sectional view showing some of the work steps and a support plate of one embodiment of a drain pipe installation method, which is one of the pipe installation methods according to the present invention. FIG. [Figure 8] 1 is a perspective view showing one embodiment of a drain pipe used in a pipe laying method according to the present invention. FIG. [Figure 9] 1 is a perspective view showing one embodiment and another embodiment of a protective pipe used in a pipe-laying method according to the present invention. FIG. [Figure 10] FIG. 2 is a perspective view showing a connection portion of a drain pipe used in the pipe laying method according to the present invention. [Figure 11] FIG. 2 is a cross-sectional view showing a connection portion of a drain pipe in the pipe laying method according to the present invention. [Figure 12]FIG. 2 is an exploded perspective view showing a connecting outer pipe for a drain pipe used in the pipe laying method according to the present invention. [Figure 13] FIG. 2 is a perspective view showing a connecting inner pipe for a drain pipe used in the pipe laying method according to the present invention. [Figure 14] FIG. 2 is an explanatory diagram illustrating an example of a connection between composite pipes in the method of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] First, one embodiment of an adit excavation method according to the present invention will be described in detail with reference to the accompanying Figs. 1 and 2.

[0019] As is clear from each drawing in FIG. 1, in the ground 11, there are a starting shaft 12 and a reaching shaft 13 excavated vertically from the surface (ground) side into the ground at a predetermined distance. The ground 11 in this case is also called a natural ground or a stratum. The starting shaft 12 and the reaching shaft 13 are so-called vertical holes, and are also called pits. Shafts such as the starting shaft 12 and the reaching shaft 13 are usually formed by well-known mechanical excavation means (vertical excavation means) using a backhoe, an auger, or the like. The starting shaft 12 and the reaching shaft 13 in the embodiment of FIG. 1 are also formed according to such a common practice. A specific example, which is merely one example of the starting shaft 12 and the reaching shaft 13, is as follows. The starting shaft 12 has a diameter in the range of 2 to 3 m, and is about 5.5 m deep from the ground. The arrival shaft 13 has a diameter in the range of 1.5 to 2 m and is approximately 5.5 m deep from the ground. The distance between the departure shaft 12 and the arrival shaft 13 is set to approximately 20 m across the center lines of the two shafts, with the vertical center lines of both shafts 12 and 13 being taken as the reference. In a typical example, the adit 14 is formed by horizontally excavating a tunnel-like shape in a straight line underground from the departure shaft 12 side (starting point side) to the arrival shaft 13 side (end point side), as described below.

[0020] The adit excavation method according to the present invention can be applied to the straight jacking method in which the adit 14 is jacked along a straight route (straight path) as described above, as well as the following construction methods. One of them is a curved jacking method in which the excavation is jacked along a curved route (curved path). The other is a mixed curved and straight jacking method in which the excavation is jacked along a curved and straight route that is a mixture of a straight route and a curved route.

[0021] In the adit excavation method illustrated in each diagram of Figure 1, the target adit hole 14 is excavated in the ground from the starting shaft 12 side toward the arrival shaft 13 side. As the machinery and associated tools and equipment required for this work, an excavator (also called a tunneling machine) 61, hydraulic mechanism 62, hydraulic jack 63, and others are installed or positioned in the starting shaft 12. Devices, machines, equipment, tools, etc. (not shown) may also be provided in the arrival shaft 13 as necessary.

[0022] The above-mentioned adit 14 excavated and formed by the adit excavation method according to the present invention, i.e., the adit 14 for laying the required pipes, is formed underground from the starting shaft 12 side to the arrival shaft 13 side, as already described. More specifically, the excavation means required for excavating the adit is installed in a predetermined place such as inside the starting shaft 12, and the work steps (processes) described below are carried out. As a specific construction method for carrying out this, well-known construction methods such as the mud pressure jacking method, the mud pressure jacking method, and the thick mud jacking method are adopted.

[0023] In conventional adit excavation and pipe laying methods, for example, when small-diameter pipes are advanced over long distances (long sections), a thrust device may be installed in the adit 14. This is a common technical matter when advancing pipes over long distances in the adit excavation and pipe laying methods of the present invention. However, when laying small-diameter pipes in the adit 14 in the adit excavation and pipe laying methods of the present invention, such a thrust device is rarely used. Furthermore, when advancing small-diameter pipes in the adit 14 in the adit excavation and pipe laying methods of the present invention, a thrust device in which the thrust ring, the base thrust jack, and the thrust angle are integrated with the thrust stand may become standard equipment. A specific example of the adit excavation method of the present invention is as follows.

[0024] In Fig. 1, a well-known excavator 61 is first prepared in the starting shaft 12 as a means for carrying out the required work steps, for example, a means for carrying out a mud pressurization method. In this case, the excavator 61 is equipped with well-known machines or machine parts such as an excavation cutter, a water-retaining head, a screw conveyor, etc. Also arranged in the starting shaft 12 is a well-known hydraulic mechanism 62 for pushing the excavator 61 and the thrust pipe 21 into the adit 14. The hydraulic mechanism 62 is equipped with a thrust jack 63 that can reciprocate freely.

[0025] Here, the jacking pipe 21 will be described in advance with reference to FIG. 2. As is clear from FIG. 2(A), the jacking pipe 21 has a self-evident tubular structure, and has a screw (male screw) 22 formed on its outer peripheral surface at the tip end and a screw (female screw) 23 formed on its inner peripheral surface at the rear end. The two screws 22 and 23 in FIG. 2(A) are a pair of male and female screws, and the jacking pipes can be connected to each other by screwing them into each other. In contrast, the jacking pipe 21 in FIG. 2(B) has an insertion part 21a and a receiving part 21b at both ends of the jacking pipe 21, and an annular protrusion 21c is formed on the outer peripheral surface of the insertion part 21a and an annular recess 21d is formed on the inner peripheral surface of the receiving part 21b. On the other hand, the jacking pipe 21 may have a hole-like or mouth-like opening 24 formed in the pipe wall to perform one or more of drainage, sludge distribution, soil distribution, etc. Some jacking pipes 21 are of a type that do not have an opening 24.

[0026] Regarding the propulsion pipe 21 in FIG. 2, the means for connecting (connecting) the propulsion pipes to each other will be described in detail. The insertion portion 21a and the receiving portion 21b at both ends of the propulsion pipe 21 are freely mated and detached. When the connecting and connecting means is a screw type as shown in FIG. 2(A), the pipes can be connected and separated (disconnected) by tightening and loosening a pair of male and female screws. In contrast, in a non-screw type connecting and connecting means as shown in FIG. 2(B), the protrusion 21c and the recess 21d fit into each other or come off from each other when fitting for pipe connection or fitting and detaching for pipe separation. As a connecting (connecting) means for the propulsion pipes (not shown), there are also embodiments in which a screw type connecting (connecting) structure is adopted at one end of the propulsion pipe 21 and a non-screw type connecting (connecting) structure such as a fitting type is adopted at the other end of the propulsion pipe 21. Therefore, pipes in this technical field, including the propulsion pipe 21, can be made long by connecting multiple pipes in the axial direction using a connecting means such as that shown in Figure 2 or the above-mentioned connecting means not shown.

[0027] The above-mentioned propulsion pipes can be connected to each other via a connecting connector. A representative example of the connecting connector is shown in Fig. 3. The connecting connector 25 shown in Fig. 3 is cylindrical like the propulsion pipe 21. As is clear from Fig. 3, a connecting portion 26a for inserting into one end of the propulsion pipe 21 for connection is formed at one end of the connecting connector 25, and a connecting portion 26b for receiving and connecting the other end of the propulsion pipe 21 is formed at the other end of the connecting connector 25. To describe this connecting fitting 25 in more detail, a ring-shaped protrusion 27a is formed on the outer peripheral surface of the connecting portion 26a, which has a relatively small outer diameter, and can engage with a receiving portion such as that on the inner peripheral surface of one end of the propulsion pipe 21, i.e., a receiving portion 21b as shown in FIG. 2(B), and a thread (female thread) 27b is formed on the inner peripheral surface of the connecting portion 26b, which has a relatively large outer diameter, and can engage with a thread (male thread) 23 on the outer peripheral surface of the other end of the propulsion pipe 21, as shown in FIG. 2(A). As another embodiment of the connecting fitting 25, there is one in which a thread (male thread / female thread) for connecting with the propulsion pipe 21 is formed on the inner peripheral surface of one end or the inner peripheral surface of the other end of the connecting fitting 25. In addition, with regard to the connection with both ends of the propulsion pipe, the connecting fitting 25 may be connected to one end of the propulsion pipe by a screw or to the other end of the propulsion pipe by fitting a protrusion (protrusion) and a recess (recess). Naturally, both ends of the thrust pipe 21 in this case are configured to be detachably connected to the connecting connector 25. Therefore, the thrust pipe 21 can be directly connected to each other, and can also be indirectly connected via a tubular or cylindrical connecting connector (also called a connector or connector). Furthermore, for this type of pipe connection or pipe connection, a press-fit connection means can be used in which one pipe end is press-fitted into the other pipe end, and a means for maintaining the connected state can be provided, such as providing a press-fit type protrusion for preventing the pipes from coming off on the inner and / or outer circumferential surfaces of the pipes that are fitted inside and outside, or providing a protrusion and a recess that can be engaged with each other on both pipe ends. In the press-fit connection, the pipes are connected to each other by utilizing elastic deformation depending on the material of the pipes.In these cases, the "connection of pipes" may be referred to simply as "connection," or simply as "connection," including the content already mentioned, and the connecting connector may be referred to as an "adapter" for connecting.

[0028] When the long jacking pipe 21 is lengthened by connecting the pipes to each other, it typically forms a continuous (single) tubular shape with no steps on the inner and outer circumferential surfaces of the connecting portion. The jacking pipe 21 can also be connected to the rear end (threaded portion) of the excavator 61 via the screw 22 at the tip end. The material for constructing the jacking pipe 21 may be any material having mechanical strength capable of withstanding a predetermined jacking load. Such a material is often selected from, for example, metal (e.g., steel), plastic (e.g., polyvinyl chloride), reinforced plastic, concrete, resin concrete, ceramic, china clay, etc. The jacking pipe 21 may be made of one, two, or three or more materials selected from the materials listed here. In the case of a jacking pipe 21 made of multiple materials, it can be said to be made of a composite material. In a typical example, the jacking pipe 21 is made of steel.

[0029] The reciprocating propulsion jack 63 of the hydraulic mechanism 62 illustrated in FIG. 1 moves forward (forward) toward the front periphery of the starting shaft 12 and moves backward (backward) to its original position. As is well known, the hydraulic mechanism 62 is available in various sizes, such as small, medium, and large, and the larger the hydraulic mechanism 62, the greater the capacity (output) and the longer the stroke of the propulsion jack 63. Of course, the hydraulic mechanism 62 is adopted in a size appropriate to the scale of construction and excavation conditions. Furthermore, the hydraulic mechanism 62 is selected and adopted in a size that is suitable for the diameter of the starting shaft 12, etc. In relation to the tunnel-like adit 14 that is excavated and formed, the propulsion pipe 21 is connected to the rear end of the leading excavator 61, and as the excavation length of the adit 14 increases, additional propulsion pipes 21 are connected to the rear end of the excavator 61 as appropriate. In this case, the larger or more powerful the hydraulic mechanism 62, the greater the "number of jacking pipes connected at one time" to the rear end of the excavator 61 tends to be. Conversely, when the smallest hydraulic mechanism 62 is used, the stroke of the jacking jack 63 is often only sufficient to push one (single) jacking pipe 21 or (single) excavator 61 into the adit 14. The jacking pipes can be connected to each other, or the jacking pipe 21 and the excavator 61 can be connected to each other, front to back, via the previously described screws 22 and 23 formed on the inner and outer circumferential surfaces of each end of these pipes.

[0030] In the adit excavation work of Fig. 1, when the size (diameter, length, etc.) of the adit 14 to be excavated is small, the starting shaft 12 and the arrival shaft 13 are often small according to the size, and the machinery such as the excavator 61 and the hydraulic mechanism 62 are inevitably small or medium-sized. Furthermore, the propulsion pipes 21 are pushed into the adit 14 one by one, or two connected together.

[0031] When excavating and forming the adit 14 in the construction shown in Fig. 1, as an example, about [6 steps] of work steps are carried out. In the first work step, the excavator 61 in the starting shaft 12 and the thrust pipe (primary thrust pipe) 21 connected in a straight line to the rear of it are attached to the thrust jack 63 of the hydraulic mechanism 62 with the excavator 61 side at the front, and then the excavator 61 in operation is directed to the front wall of the starting shaft 12. After this, the excavator 61, which continues to receive thrust from the thrust jack 63, is pushed from the front wall of the starting shaft 12 to the arrival shaft 13 in the next work step, whereby the strata between the shafts 12 and 13 are excavated from the starting shaft 12 side to the arrival shaft 13 side. In this way, the excavator 61, which horizontally excavates the strata between the shafts 12 and 13 from the starting shaft 12 side to the arrival shaft 13 side, enters and advances horizontally within the strata in this section accompanied by the first propulsion pipe 21.

[0032] In the embodiment of FIG. 1 in which the work proceeds in the above-mentioned steps, when the first jacking pipe 21 at the rear end of the excavator 61 is pushed into the stratum, the excavator 61 and the hydraulic mechanism 62 are temporarily stopped, and the rear end of the jacking pipe 21 at the excavator 61 side is separated from the jacking jack 63. After this separation, the jacking jack 63 of the hydraulic mechanism 62 retreats and returns to its previous position. In this state, a space is created between the rear end of the first jacking pipe 21 and the jacking jack 63 in which the next second jacking pipe 21 can be added. As a result, the second jacking pipe 21 is interposed in the space between the rear end of the first jacking pipe 21 and the jacking jack 63, the tip end of the second jacking pipe 21 is connected to the rear end of the first jacking pipe 21, and further, the rear end of the second jacking pipe 21 is connected to the tip end of the jacking jack 63. Thus, the excavator 61 equipped with the secondary propulsion pipe 21 advances horizontally underground by carrying out each of the above-mentioned work steps in a predetermined order.

[0033] When the operations described in each work step in Fig. 1 are repeated a predetermined number of times in a predetermined order, the adit 14 grows until it penetrates between the starting shaft 12 and the arrival shaft 13 in a tunnel-like shape. This completes the adit 14 to a predetermined length. A series of jacking pipes 21 are laid in the completed adit 14 over its entire length. At this stage, the excavator 61, which has penetrated the adit 14 and protruded into the arrival shaft 13, is detached from the leading jacking pipe 21, separated, and taken into the arrival shaft 13, and then transported from the arrival shaft 13 to the ground.

[0034] The series of jacking pipes 21 laid in the adit 14 in each work step of Fig. 1 are then removed to the outside of the adit 14 in the next work step of Fig. 1. During this removal, the series of jacking pipes 21 in the adit 14 are removed from the adit 14 to a vertical shaft while being uncoupled, for example, one by one, and the removed jacking pipes 21 are carried to the ground side. The vertical shaft from which the pipes are removed at this time may be either the departure shaft 12 or the arrival shaft 13. Fig. 1 shows an example in which the jacking pipes 21 in the adit 14 are removed to the arrival shaft 13 side through the jacking pipe removal work.

[0035] An example of the above-mentioned thrust pipe removal is as follows, with reference to FIG. 1. First, the thrust jack 63 of the hydraulic mechanism 62, which is in an advanced state in FIG. 1, is connected to one end of the thrust pipe 21 exposed or protruding toward the starting shaft 12. Next, the thrust jack 63 connected to the thrust pipe 21 is retreated, and the thrust pipe 21 is pulled out of the adit 14. In the subsequent work step, the thrust pipe 21 pulled out from the adit 14 to the starting shaft 12 is released from the thrust pipe 21 in the adit 14 and separated from the pipe. This thrust pipe pulling out and thrust pipe separation are performed until all the thrust pipes 21 are removed from the adit 21. Each thrust pipe 21 pulled out from the adit 14 to the starting shaft 12 or released (separated) in this way is carried out from the starting shaft 12 to the ground, either individually or in a group of several. In another example of the removal of the thrust pipes, the thrust pipes 21 that have been pulled out from the adit 14 to the arrival shaft 13 are disconnected from the thrust pipes 21 in the adit 14 and separated from there. The thrust pipe removal and thrust pipe separation in this case are also performed until all the thrust pipes 21 are removed from the adit 21. The thrust pipes 21 that have been pulled out from the adit 14 to the arrival shaft 13 or that have been released (separated) from the arrival shaft 13 are carried out to the ground from the arrival shaft 13, either individually or in groups of several.

[0036] The above-mentioned work step of placing the jacking pipe 21 over the entire length of the adit 14 is performed only once at the very least. However, depending on the embodiment, the work step of placing the jacking pipe 21 over the entire length of the adit 14 may be performed multiple times, for example, two or more times. When such a work step is performed multiple times, the work of removing the jacking pipe 21 from the adit 14 is also performed each time the jacking pipe 21 is placed over the entire length of the adit 14. More specifically, when the jacking pipe 21 is placed three times in the adit 14, the following repeated work is performed: [Placing the jacking pipe in the adit] → [Removing the jacking pipe from the adit] → [Placing the jacking pipe in the adit] → [Removing the jacking pipe from the adit] → [Placing the jacking pipe in the adit] → [Removing the jacking pipe from the adit] → [Placing the jacking pipe in the adit] → [Removing the jacking pipe from the adit].

[0037] When the jacking pipe 21 is inserted multiple times in the adit 14 as described above, the poor condition of the adit's inner peripheral surface is improved or the finished condition of the adit's inner peripheral surface is improved in proportion to the number of insertions. The number of insertions of the jacking pipe 21 in the adit is determined by taking into consideration various circumstances related to the construction, such as the scale of the construction, the construction schedule, the progress of the work, and the construction budget.

[0038] In the case of the adit excavation method carried out through each work step as described above, the following points can be said to be desirable. That is, the inner diameter and inner peripheral surface of the adit 14 are finished with high precision depending on the outer diameter and outer peripheral surface of the thrust pipe 21. In particular, the inner peripheral surface of the adit 21 is smoothed and rubbed by the action of a trowel on the smooth outer peripheral surface of the thrust pipe 21. Therefore, the adit 21, especially the inner peripheral surface, is finished in an extremely good condition.

[0039] As the next embodiment of the pipe-laying method according to the present invention, a pipe-laying method for laying a composite pipe will be described with reference to the illustrated example in Figs.

[0040] The composite pipe 31 used in the pipe-laying method in Fig. 4 is a protective pipe 51 with a drain pipe 41 inside, as shown in Fig. 5(A) and Fig. 6. Therefore, the composite pipe 31 can be said to be a protective pipe with a drain pipe inside. In the pipe-laying method in Fig. 4, such a composite pipe 31 is laid in the adit 14. Therefore, in the pipe-laying method according to the present invention, the components of the composite pipe 31, such as the protective pipe 51 and the drain pipe 41, will be explained prior to the laying process.

[0041] The protective pipe 51, which is one of the components of the composite pipe 31, is a circular pipe having a circular cross section in a representative example shown in FIG. 4. This can be understood from, for example, FIG. 5(A) and FIG. 6. The protective pipe 51 has a bore that allows the drain pipe 41 to be slidably inserted therein. The protective pipe 51 must also be able to withstand at least the pipe thrust force (the force of inserting the pipe into the adit 14) by the thrust jack 63 of the hydraulic mechanism 62. Therefore, the protective pipe 51 has mechanical properties (mechanical strength) that allow it to withstand such a pipe thrust force. On the other hand, as shown in FIG. 9(A)(B), the pipe wall of the protective pipe 51 may have an opening 54 such as a hole or mouth for draining water, distributing mud, or distributing soil, as necessary. As for the specific material of the protective pipe 51, as explained for the propulsion pipe 21, it is made of a material having one or more of the following materials: metal (e.g., steel), plastic (e.g., polyvinyl chloride), reinforced plastic, concrete, resin concrete, clay, composite material (e.g., composite material of metal and synthetic resin), etc. A typical protective pipe 51 is made of steel.

[0042] To explain the protective tube 51 in more detail, in the case of the protective tube 51 illustrated in FIG. 9(A), a male thread 52a is formed on the outer peripheral surface of one end of the protective tube 51, and a female thread 53a is formed on the inner peripheral surface of the other end of the protective tube 51. In this case, the two threads 52a and 53a are paired so that they can be screwed into each other. In this case, the two protective tubes 51 are connected in a continuous tubular shape by screwing the thread 52a of one protective tube 51 and the thread 53a of the other protective tube 51 into each other. In contrast, the protective tube 51 illustrated in FIG. 9(B) has an annular protrusion 52b formed on the outer peripheral surface of one end of the protective tube 51, and an annular recess 53b formed on the inner peripheral surface of the other end of the protective tube 51. These annular protrusions 52b and annular recesses 53b are paired so that they can be fitted into and removed from each other. When the tube end of one protective tube 51 is fitted with the tube end of the other protective tube 51, the annular projection 52b and the annular recess 53b engage with each other, maintaining the connected state of both protective tubes 51. Therefore, in the case of protective tubes 51, two or more can be connected in the axial direction in this manner, thereby making it possible to create a connected protective tube of a required length. Furthermore, by connecting multiple protective tubes 51 in the axial direction, it is possible to create a longer connected protective tube.

[0043] Next, the drain pipe 41 will be described in detail. The drain pipe 41 shown in FIG. 8 is also a circular pipe with a circular cross section. This drain pipe 41 has water permeability. This is because the pipe wall of the drain pipe 41 has water permeability due to its structure. A representative example of the drain pipe 41 is a network pipe or tube made of a thermoplastic resin such as polypropylene. A network pipe (network tube) is, for example, made of entangled strands (cord-like material), and the contact points of the strands are joined together. As for the specific dimensions, the network pipe has a length of 1 m, a pipe wall thickness of about 180 mm, and a diameter of the strands is about 2 mm. Incidentally, the drain pipe 41 made of such a network pipe has a pressure resistance strength capable of withstanding the pressure of an earth covering thickness of about 7 m.

[0044] In the case of the drain pipe 41 in the embodiment of Fig. 8, the outer circumferential surface is covered with a water-permeable filter material 42, or the outer circumferential surface of the water-permeable filter material 42 is covered with a mesh body 43. The filter material 42 has a function of preventing the drain pipe 41 buried underground from early clogging due to the intrusion of sand and the like, and the mesh body 43 has a function of preventing the tip of the filter material 42 from being curled up and compressed due to friction with the inner surface of the rest of the pipe. The filter material 42 is made of a nonwoven fabric as an example, and the mesh body 43 is made of a hard resin as an example. There are some drain pipes 41 in which the mesh body 43 is omitted, and some in which both the filter material 42 and the mesh body 43 are omitted.

[0045] As will be apparent from the following description, drain pipes 41 are formed into a long pipe of the required length by connecting (joining) multiple drain pipes in the longitudinal direction. A plurality of (two or more) annular grooves 44 are formed at both ends of the pipe wall of drain pipe 41 for use in connection. In addition, an inner pipe made of, for example, hard synthetic resin may be installed inside drain pipe 41. Among these, annular groove 44 corresponds to an annular protrusion 46 of a connecting outer pipe 45 described later so as to be freely fitted therein. In the case of an inner pipe installed inside drain pipe 41, it may also be used for connecting drain pipes to each other as described later.

[0046] Drain pipes 41 are connected to make them longer. The parts and members illustrated in Fig. 12 and Fig. 13 are used to connect drain pipes to each other. Specifically, they are a connecting outer pipe 45, a connecting inner pipe 48, and parts (members) associated with them. These will be described below with reference to Fig. 12, Fig. 13, Fig. 14, etc.

[0047] When connecting two drain pipes, as is clear from Fig. 14, the connecting end faces of the two drain pipes 41 are butted together in a straight line to keep both drain pipes 41 straight. In this case, the connecting outer pipe 45 is attached to the outer circumferential surface of the drain pipe connection part. The connecting outer pipe 45 is made of a hard synthetic resin that is difficult to deform, and in terms of shape and structure, it is a two-split circular half pipe as shown in Fig. 12. The connecting outer pipe 45 becomes a circular pipe when two split members are combined, and becomes two half circular pipes when disassembled. Annular projections 46 that freely fit into the annular recessed grooves 44 of the drain pipe 41 are formed on both ends of the pipe wall of the connecting outer pipe 45.

[0048] When two drain pipes 41, the connection end faces of which are butted against each other, are firmly connected by the connecting outer pipe 45, for example, two half-circular pipes (split-shaped members) in a disassembled state as shown in FIG. 12 are attached to the outer circumferential surfaces of the connection parts of the drain pipes 41, which are butted against each other. This attachment causes the two half-circular pipes (split-shaped members) to be combined into a circular pipe shape on the outer circumferential surfaces of the drain pipes 41. At this time, the annular groove 44 of the drain pipe 41 and the annular protrusion 46 of the connecting outer pipe 45 also fit into each other. A fastening band 47 made of metal or the like is applied to the recessed portion of the outer circumferential surface of the annular protrusion 46 of the connecting outer pipe 45 in such an attached state, and the fastening band 47 is fastened. The combined attachment state of the connecting outer pipe 45 on the outer circumferential surfaces of the drain pipes 41 is maintained by the fastening force of the fastening band 47, and the connection state of the drain pipes 41 is maintained. This connecting work is performed on the ground as an example, and in a shaft such as the starting shaft 12 as another example.

[0049] The connecting inner pipe 48 for a drain pipe shown in Fig. 13 is also made of, for example, a hard synthetic resin or metal that is difficult to deform. As is clear from Fig. 13, the connecting inner pipe 48 has a plurality of (about four) locking claws 49 distributed in the circumferential direction on the outer circumferential surface at both ends. Incidentally, the illustrated locking claws 49, which are formed by protruding part of the pipe wall of the connecting inner pipe 48 outward, are provided with a gradient that is inclined in a predetermined direction. When the connecting inner pipe 48 is inserted into the end of the drain pipe 41, each of these locking claws 49 bites into the inner circumferential surface of the end.

[0050] The connecting inner pipe 48 is inserted into the rear end of the drain pipe 41 by fitting about 1 / 2 of its length. Therefore, about 1 / 2 of the connecting inner pipe 48 is exposed to the outside from the rear end side of the drain pipe 41. The connection work of the drain pipes 41 using the connecting inner pipe 48 is performed on the ground as an example, or in the starting shaft 12 as another example. More specifically, the connecting inner pipe 48, which can bite into and be fixed to the inner peripheral surface of the drain pipe 41 via the locking claws 49, is fitted and inserted into the rear end of the drain pipe 41 in advance. When connecting the drain pipes 41 to each other, for example, connecting one drain pipe 41 to the other drain pipe 41, about 1 / 2 of the connecting inner pipe 48 exposed to the outside from the rear end of one drain pipe 41 is fitted and inserted into the inside of the other drain pipe 41 from the tip end of the other drain pipe 41. The connection of the drain pipes to each other by the connection inner pipe 48 is performed prior to the connection of the drain pipes to each other by the connection outer pipe 45 .

[0051] There are several patterns for connecting drain pipes to each other. One of them is a connection pattern using a connecting outer pipe 45 and a fastening band 47. In this case, connection is not made using a connecting inner pipe 48. The other is a connection pattern using a connecting inner pipe 48. In this case, connection is not made using a connecting outer pipe 45 and a fastening band 47. Still another is a connection pattern using not only a connecting outer pipe 45 and a fastening band 47 but also a connecting inner pipe 48. Which connection pattern to adopt is decided taking into consideration various circumstances related to the construction work.

[0052] The above-mentioned connecting outer pipe 45 can be referred to as a connecting outer tube, a connecting outer tube, or a connecting outer tube, and the above-mentioned connecting inner pipe 48 can be referred to as a connecting inner tube, a connecting inner tube, or a connecting inner tube. In this case, the words "connection" and "connection" are almost synonymous as already mentioned, and there is no difference in meaning.

[0053] As is clear from Figs. 5 and 6, the composite pipe 31 used in the pipe-laying method according to the present invention is a combination of a relatively small-diameter drain pipe 41 and a relatively large-diameter protective pipe 51, which are fitted together. Of course, in the case of both pipes 41 and 51, the outer diameter of the drain pipe 41, which is the inner pipe, is smaller than the inner diameter of the protective pipe 51, which is the outer pipe, but the difference between the inner and outer diameters is small. The difference between the inner and outer diameters is such that a minute gap is generated between the outer peripheral surface of the drain pipe and the inner peripheral surface of the protective pipe. The existence of such a minute gap between the two pipes 41 and 51 that constitute the composite pipe 31 allows the drain pipe 41 and the protective pipe 51 to slide relative to each other along the axial direction. Therefore, in the case of the composite pipe 31, it can be said that the drain pipe 41, which is the inner pipe, and the protective pipe 51, which is the outer pipe, are combined inside and outside so as to be slidable (slidable) in the axial direction. The connection of the composite pipes is (can be) made in a state where the rear end (or front end), which is the connection end of the drain pipe 41, protrudes outward from the rear end (or front end) of the protective pipe 51. In this case, the connection of the composite pipes means the connection of the drain pipes and the protective pipes, which are components of the composite pipe 31, and means that these two types of pipe connections are made.

[0054] The above-mentioned composite pipe 31 is connected as follows, for example. This will be described with reference to Fig. 14(a)-(c). First, as shown in Fig. 14(a), the rear end (connection end) of one drain pipe 41 and the front end (connection end) of the other drain pipe 41 are butted against each other. That is, the two drain pipes 41 are butted against each other so that they are aligned in the axial direction in a straight line (serial state). A split-type connection outer pipe 45 is attached to the butted portion of the two drain pipes 41 over its outer periphery, as shown in Fig. 14(b). A fastening band 47 is attached to an annular protrusion 47 of the connection outer pipe 45, and this is fixed in a fastened state. The two drain pipes 41 aligned in the axial direction in an butted state are stably connected by the fastening force of the fastening band 47. After this, as shown in Fig. 14(c), a protective pipe 51 is placed over the outer periphery of the rear drain pipe 41, and the rear protective pipe 51 and the front protective pipe 51 are screwed together (connected) via their male threads 52a and female threads 53a. Thus, a connection between two front and rear drain pipes or two front and rear protective pipes corresponds to a connection between two front and rear composite pipes. Therefore, the composite connection of different types of pipes as shown in Fig. 14(c) can be said to be a connection between two front and rear composite pipes 31.

[0055] A method for laying a composite pipe 31, which is one of the pipe laying methods according to the present invention, will be described with reference to FIG.

[0056] When the composite pipe laying method is used, as is self-evident, the composite pipe 31 is laid in the adit 14. There are roughly two types of composite pipe laying methods. In one method, when a jacking pipe 21 is present over the entire length of the adit 14, the jacking pipe 21 is pushed out of the adit 21 by the composite pipe 31 (particularly the end face of the protective pipe 51) and the composite pipe 31 is laid in the adit 21 in place of the jacking pipe 21. In the other method, the composite pipe 31 is laid in the adit 21 after the jacking pipe 21 has been removed. The composite pipe 31 handled in each of these embodiments will become clearer with reference to the detailed description given below.

[0057] The composite pipe laying method also includes each of the work steps for forming an adit as explained in the above-mentioned adit excavation method, to which a work step for laying a composite pipe is added. Therefore, in the case of this composite pipe laying method, the explanation of those steps will be omitted by referring to the above-mentioned explained work steps, and the following will mainly explain the work step for laying a composite pipe that is carried out after the final work step of the explained work steps.

[0058] 4(A) and (B), a horizontal adit 14 is formed underground between the starting shaft 12 and the arrival shaft 13 by carrying out the above-mentioned work steps. After the formation of this adit, the work step for laying the composite pipe 31 is carried out. The work steps for laying the composite pipe are as follows.

[0059] In the case of the composite pipe laying work in Fig. 4 (A) (B), the composite pipe 31 is pushed into the adit 14 while being added in the axial direction. The hydraulic mechanism 62 is used for this pushing. As described above, the pushing jack 63 of the hydraulic mechanism 62 is equipped with the pushing base 64 and the reaction wall (bearing wall) 65 provided at the rear end of the pushing base 64. The upper surface of the pushing base 64 of the pushing jack 63 has a shape and structure corresponding to the lower half of the composite pipe 31, so that the lower half of the composite pipe 31 can be supported by the upper surface side of the pushing base 64. The pushing jack 63 also has a front surface of the reaction wall 65 to which a pressure wheel or a pressure plate is attached, which corresponds to the rear end surface of the composite pipe 31 (the rear end surface of the drain pipe 41 and the rear end surface of the protection pipe 41). Of course, this thrust jack 63 can also push the composite pipe 31 from its rear end side at the front side of the reaction wall 65. Therefore, when the composite pipe 31 is pushed into the adit 14 by the thrust jack 63, its lower half is supported by the thrust base 64 and its rear end face is placed against the front part of the reaction wall 65. In this state, the pushing force of the thrust jack 63 acts on the drain pipe 41 and the protective pipe 51 as specified. Furthermore, since the protective pipe 51, which has a greater compressive strength, receives a large thrust force from the thrust jack from the front part of the reaction wall, only a light thrust force is applied to the drain pipe 41, enough to enter the adit 14. Therefore, when the composite pipe is laid, the drain pipe 41 is not deformed by the thrust force of the thrust jack 63.

[0060] In the case of the composite pipe 31, which is pushed and pressurized by the thrust jack 63 in the above-mentioned work, an attachment is attached to connect the rear end face of the composite pipe 31 to the front face of the reaction wall 65 in order to protect the drain pipe 41 and the protective pipe 51, which are its components, and to stabilize the holding state by the thrust jack 63. That is, a support pipe 67 as shown in FIG. 5(B) is interposed between the composite pipe 31 and the reaction wall 65. The support pipe 67 is a member in which a circular base plate 68 and a cylindrical short pipe 69 are integrally formed, and the short pipe 69 protrudes from the front side of the base plate 68. In this case, the base plate 68 of the support pipe 67 can push the rear end face of the drain pipe 41 in the composite pipe 31. The short pipe 69, which is a part of the support pipe 67, also has a diameter approximately equal to that of the protective pipe 51, so that the front face of the short pipe 69 can push the rear end face of the protective pipe 51. As a means for attaching the support pipe 67 to both the composite pipe 31 and the reaction wall 65 (pressing portion 66), appropriate means such as the screws (male and female threads) and known fasteners (bolts) described above are used. In addition, attachments such as a connecting pipe (similar to the connecting pipe 22 described below) and the pressure wheel and pressure plate may be interposed and fixed between the two parts 31 and 65 as necessary. This type of attachment is made of a suitable material depending on the situation, such as a robust material, a material with elasticity or cushioning (shock-absorbing properties), or a semi-rigid material. They are made of soft or semi-rigid plastic, or a composite material of plastic and other materials (e.g. metal).

[0061] In the work steps of Fig. 4(A) and (B), the composite pipes 31 are inserted into the adit 14 in a line (straight) while being added one after another. In the composite pipe connection at this time, the drain pipes as inner pipes and the protective pipes as outer pipes are respectively connected to each other. As shown in Fig. 5, the composite pipe 31 located at the front of the composite pipe connection is covered with a tapered pipe-shaped cover 32 made of a soft or semi-hard elastically deformable material (rubber or synthetic resin) from the outer peripheral surface of the tip of the drain pipe 41 to the outer peripheral surface of the tip of the protective pipe 51. The inner peripheral surface of the tip of the cover 32 fits closely to the outer peripheral surface of the drain pipe 41, and the rear end is fixed to the protective pipe 51 by, for example, a metal fastening band 33 or a screw 34. The cover 32 is functionally a packing. The cover 32 as a packing mainly prevents foreign matter such as soil and sand from entering the gap between the compound pipes 31 (between the outer peripheral surface of the drain pipe tip and the inner peripheral surface of the protective pipe tip). In addition, for each compound pipe 31 that is lined up in the adit 14, a connecting pipe 22 may be interposed as necessary at the boundary between them, as shown diagrammatically in Figure 3. The connecting pipe 22 is often a short pipe that resembles a shortened version of the propulsion pipe 21. Both ends of the connecting pipe 22 may have threads (male and female threads) for connecting the pipes.

[0062] 4(A)(B), for convenience of explanation, the composite pipe 31 with cover 32 that is pushed and inserted into the adit 14 first will be referred to as the first composite pipe 31, and the composite pipes 31 that are pushed and inserted into the adit 14 second, third, fourth, etc. will be referred to as the second composite pipe 31, third composite pipe 31, fourth composite pipe 31, etc., respectively. For convenience of explanation, the drain pipes 41 and protective pipes 51 that are components of the first composite pipe 31, second composite pipe 31, third composite pipe 31, fourth composite pipe 31, etc. will also be referred to as the first drain pipe 41, second drain pipe 41, third drain pipe 41, fourth drain pipe 41, etc., or as the first protective pipe 51, second protective pipe 51, third protective pipe 51, fourth protective pipe 51, etc., respectively.

[0063] 4(A)(B), first, the first compound pipe 31 is pushed into the adit 14. That is, the front end face of the first compound pipe 31 is placed against the rear end face of the rearmost jacking pipe 21 protruding out of the adit 14 in the starting shaft 12, and then it is pushed into the adit 14 via the jacking jack 63 of the hydraulic mechanism 62. More specifically, after the support pipe 67 is interposed and fixed between the rear end face of the first compound pipe and the front side of the jacking jack, the first protective pipe 51 and the first drain pipe 41 are pushed in as a synchronous (simultaneous) pushing operation by the jacking jack 63, so that the first compound pipe 31 enters the adit 14.

[0064] 4(A)(B), when the first compound pipe 31 is pushed into the adit 14 from the starting shaft 12 side as described above, the driving jack 63 of the hydraulic mechanism 62 temporarily stops and then returns to its original position. This makes it possible to perform the next compound pipe pushing operation.

[0065] In the case of the first compound pipe 31 that is pushed and inserted into the adit 14, the outer peripheral surface of the rear end of the first drain pipe 41 (the outer peripheral surface of the connection end) is exposed in the starting shaft 12, and the rear end (the connection end) of the first protective pipe 51 is close to one end of the adit 14 (the end on the starting shaft 12 side). Therefore, when connecting the tip end of the second compound pipe 31 to the rear end of the first compound pipe 31, the rear end of the first drain pipe 41 and the tip end of the second drain pipe 41, and the rear end of the first protective pipe 51 and the rear end of the second protective pipe 51 are connected to each other. The specific connection in this case is as follows. First, in the case of the first drain pipe 41 and the second drain pipe 41, the front end of the second drain pipe 41 is butted against the rear end of the first drain pipe 41, and the split-type connecting outer pipe 45 is covered on the outer circumferential surface of the butted portion of both pipes, and the split-type connecting outer pipe 45 is fastened with a fastening band 47 to connect them. That is, the first drain pipe 41 and the second drain pipe 41 are connected to each other via the connecting means described above with reference to FIG. 5. Next, in the case of the rear end of the first protective pipe 51 and the second protective pipe 51, since the pair of male and female screws 52a and 53a described above are provided at their respective ends, the rear end of the first protective pipe 51 is screwed into the front end of the second protective pipe 51. That is, the first protective pipe 51 and the second protective pipe 51 are screwed to each other. When connected in this manner, the second drain pipe 41 and the second protective pipe 51 overlapping inside and outside constitute the second composite pipe 31. Therefore, this can be said to be a connection that accompanies the fabrication of the compound pipe 31. When the pipes are connected to each other in this way, the connection of the second compound pipe 31 to the first compound pipe 31 is completed, so here too, the second compound pipe 31 and the propulsion jack 63 are connected by a support pipe 67.

[0066] 4(A)(B), the second compound pipe 31 is pushed into the adit 14 by the driving jack 63 of the hydraulic mechanism 62, as described above. More specifically, the driving jack 63 pushes in the second protective pipe 51 and the second drain pipe 41 at the same time. The second compound pipe 31 advances the first compound pipe 31 by this pushing, and also enters the adit 14. The respective driving pipes 21 in a line in the adit 14, i.e., the driving pipe array, are pushed toward the arrival shaft 13 by the second protective pipe 51 entering the adit again at this time. Therefore, the driving pipe 21 at the head of the driving pipe array escapes from the adit 14 and enters the arrival shaft 13. The driving pipe 21 that entered the arrival shaft 13 is also disconnected from the driving pipe array and taken into the arrival shaft 13, and then carried out from there to the ground side. During this time, the propulsion jack 63 of the hydraulic mechanism 62 returns to its previous position as described above, maintaining a posture in which the next composite pipe pushing operation can be performed.

[0067] The second compound pipe 31, which is pushed into the adit 14, has the outer peripheral surface of the rear end of the second drain pipe 41 exposed in the starting shaft 12, and the rear end of the second protective pipe 51 close to one end of the adit 14. When the tip of the next third compound pipe 31 is connected to the rear end of this second compound pipe 31, the rear end of the second drain pipe 41 and the tip of the third drain pipe 41 are connected to each other, and the rear end of the second protective pipe 51 and the rear end of the third protective pipe 51 are connected to each other in the same manner as described above. Even when such a pipe connection is made, the third compound pipe 31 is constituted by the third drain pipe 41 and the third protective pipe 51 overlapping inside and outside. Furthermore, the third compound pipe 31 is connected to the driving jack 63 via the support pipe 67, as described above.

[0068] The third compound pipe 31 is pushed into the adit 14 in the same manner as described above. The third protective pipe 51 is pushed in by the driving jack 63, and at the same time, the third drain pipe 41 is pushed in by the pushing part 66 of the driving jack 63. Thus, the third compound pipe 31 advances into the adit 14 while advancing the first compound pipe 31 and the second compound pipe 31. At this time, the second protective pipe 51 entering the adit 14 pushes the adit 14 array toward the arrival shaft 13, so that the adit 21 at the head of the adit 14 escapes from the adit 14 and enters the arrival shaft 13. The adit 21 in the tunnel is also disconnected from the adit 14 array and taken into the arrival shaft 13, and then carried out to the ground. During this time, the propulsion jack 63 of the hydraulic mechanism 62 returns to its previous position as described above, maintaining a posture in which the next composite pipe pushing operation can be performed.

[0069] When pushing and inserting the fourth compound pipe 31 and the subsequent compound pipes 31 into the adit 14, all the main operations are substantially the same as or similar to those described above. That is, for the leading compound pipe 31 and the subsequent compound pipes 31 that are in a leading-rear relationship on the starting shaft 12 side, the leading end of the subsequent compound pipe 31 is connected to the rear end of the leading compound pipe 31, or the support pipe 67 is interposed and fixed between the predetermined parts, and then the subsequent compound pipe 31 is pushed and inserted into the adit 14 by the driving jack 63 of the hydraulic mechanism 62. On the other hand, the driving pipe array remaining in the adit 14 also escapes from the adit 14 and enters the arrival shaft 13 every time the compound pipe 31 is pushed and inserted into the adit 14, and is removed and carried to the ground side as described above. Therefore, in the case of the work step illustrated in Figure 4 (B), the composite pipe has been pushed into the adit 14 a predetermined number of times, which indicates the stage at which a series of composite pipes 31 have been laid from the starting shaft 12 side to the arrival shaft 13 side, i.e., the stage at which the laying of the series of composite pipes penetrating the adit 14 has been completed.

[0070] After the composite pipe 31 has been laid in the adit 14 in a connected state as described above, each protective pipe 51, which is a component part of the connected composite pipe 31, is pulled out from the adit 14 to the starting shaft 12 side or the arrival shaft 13 side, and then removed. This will be described below with reference to FIG. 7.

[0071] In the case of each drain pipe (connected drain pipe) 41 laid in the adit 14 together with the protective pipe 51 in the above-mentioned connected (coupled) state, it is held as a temporary retention measure so as not to escape from the adit 14. That is, each drain pipe 41 is held in a retained state in the adit 14 so as not to move from there. As a means for retaining the connected drain pipes (41·41·41……) in a retained state in the adit, examples thereof shown in Figs. 7(A) and (B) include a retaining rope 71 having tensile strength for retaining or mooring, disk-shaped or ring-shaped retaining plates 72·73, and a mooring device 76. The retaining rope 71 is typically made of a wire rope, and the retaining plates 72·73 and the mooring device 76 are typically made of metal, and another example is made of synthetic resin. The outer diameter of both the disk-shaped or ring-shaped retaining plates 72·73 is equal to or slightly smaller than the outer diameter of the drain pipe 41. 7(C), holes 74, 75 are formed in the center of the retaining plates 72, 73 for passing the retaining cord 71 through. The retaining plates 72, 73 may further have one or more holes (not shown) formed in their surfaces for fastening and securing the retaining cord 71 to the retaining plates 72, 73, and / or one or more fasteners (not shown) attached to their surfaces for fastening the retaining cord 71 to the retaining plates 72, 73.

[0072] As is clear from Figures 7(A) and (B), the two holding plates 72 and 73 are concentrically fitted to the rear end faces (starting shaft 12 side) and front end faces (arrival shaft 13 side) of the connecting drain pipes (41·41·41...). That is, the two holding plates 72 and 73 are overlapped concentrically to both end faces of the connecting drain pipes (41·41·41...). Therefore, in this case, the outer peripheries of the two holding plates 72 and 73 do not extend into the end face area of ​​the protective pipe 51. The holding cable 71 is passed through the holding plate 72 fitted to the rear end faces of the connecting drain pipes (41·41·41...) and the holding plate 73 fitted to the front end faces of the connecting drain pipes (41·41·41...). As a specific example, the tip of the holding rope 71, which has passed through the hole 75 of one holding plate 73 from the arrival shaft 13 side, is pulled through the inside of the connecting drain pipe (41·41·41...) and then through the hole 74 of the other holding plate 72. The end of the holding rope 71 on the holding plate 72 side is fixed to the holding plate 72 by appropriate means such as tying or metal fittings. The end of the holding rope 71 on the holding plate 73 side can be tightened by a known appropriate tightening device (not shown) such as a jack type, winch type, or other type. In this case, for example, a return stop metal fitting is attached to the holding plate 73 in correspondence with the hole 75, and the end of the holding rope 71 on the holding plate 73 side is tightened by the tightening device and the tightened state is clamped. In this way, the distance between the two retaining plates 72 and 73 is shortened slightly, so that the connecting drain pipes (41, 41, 41 ...) are subjected to compressive pressure from both axial ends. As a result, the connecting drain pipes (41, 41, 41 ...) are gathered together in the axial direction and are sandwiched and held by the two retaining plates 72 and 73. The end of the retaining rope 71 on the retaining plate 73 side is further firmly anchored to an anchor-like anchor 76 attached to the rear peripheral surface of the arrival shaft 13 by a known appropriate anchoring means (fastening or metal fitting). With the other end of the retaining rope 71 fixed to the rear peripheral surface of the arrival shaft 13 in this way, the connecting drain pipes (41, 41, 41 ...) are retained in the adit 14.In other words, even if a force (pulling force) acts on the connecting drain pipes (41·41·41...) to pull them out from within the adit 14 toward the starting shaft 12, the connecting drain pipes (41·41·41...), which are held in a stationary state within the adit via retaining ropes 71 or the like, will remain within the adit 14 against this pulling force (pulling force).

[0073] After each drain pipe 41 in a connected state is held in the adit tunnel as shown in Fig. 7(A)(B), when the series of protective pipes 51 (protective pipe array) in a connected state in the adit tunnel 14 is to be completely removed from the adit tunnel 14, the rear end of the last protective pipe 51 on the starting shaft 12 side is connected to the propulsion jack 63 of the hydraulic mechanism 62 by a support pipe 67, and then the protective pipe array is pulled out from the adit tunnel 14 by the force of the hydraulic mechanism 62. A specific example is as follows. In the first operation, the propulsion jack 63 moves forward and backward to one end side of the adit tunnel 14 with a predetermined stroke. In the second operation, the last protective pipe 51 and the propulsion jack 63 are connected via the support pipe 67 used in the previous step, for example. In the third operation, the propulsion jack 63 of the hydraulic mechanism 62 moves back (returns). The protective tube array is connected to the returnable driving jack 63 as described above. Therefore, the protective tube array is pulled out from the adit 14 to the starting shaft 12 by the return stroke of the driving jack 63. The number of protective tubes 51 pulled out from the adit 14 to the starting shaft 12 and exposed in the starting shaft 12 is determined by considering the scale of construction, the diameter of the starting shaft 12, the work process plan, etc. In the illustrated embodiment, for convenience of explanation, the protective tube array is pulled out from the adit 14 by the length of one protective tube per return stroke of the driving jack 63. In this way, the connection parts between the protective tubes are also exposed in the starting shaft 12 when the protective tube array is pulled out from the adit 14, so that one protective tube pulled out into the starting shaft 12 can be easily separated from the protective tube array. The fourth operation is to release the connection between the rearmost protective pipe 51 and the support pipe 67, and to separate the rearmost protective pipe 51 from the protective pipe array. Of course, the drain pipe array (the drain pipes 41 in a series of connected state) that is held in a stationary state in the adit 14 as described above is not affected by the pulling out and remains in the adit 14 because it is in a stationary state in the adit. The fifth operation is to carry the protective pipe 51 that has been separated from the protective pipe array to the ground side.

[0074] 7(A)(B), the first to fifth steps are repeated until the protective pipe array is pulled out from the adit 14, the protective pipes 51 exposed in the starting shaft 12 are separated from the protective pipe array, and the separated protective pipes 51 are carried to the ground. When the last protective pipe 51 is pulled out from the adit 14 and carried to the ground, the main work of the drain pipe installation method is almost complete except for minor work.

[0075] The above-mentioned connection protection pipe 51 can also be removed from within the adit 14 from the arrival shaft 13 side, for example, when an extraction means is provided on the arrival shaft 13 side, or when a means for retaining the connection drain pipe (41·41·41...) within the adit is provided on the departure shaft 12 side. [Industrial Applicability]

[0076] In the case of the adit excavation method according to the present invention, a tunnel-like adit that runs horizontally underground is excavated while using a thrust pipe, so that a high-precision and good adit can be formed by relying on the special feature of using a thrust pipe. This is of great benefit to the construction department that creates the adit, and therefore has a high industrial applicability.

[0077] When using the composite pipe laying method of the present invention, a good access tunnel is first formed, and then the composite pipe is laid in the good access tunnel. This is because the laying of the composite pipe is carried out separately from the formation of the access tunnel, which is difficult. With composite pipe This method enables safe, accurate and easy drain pipe installation, shortens the installation period, reduces installation costs, etc. Therefore, this method has a high industrial applicability as a drain pipe installation method.

[0078] The pipe laying method of the present invention is based on a composite pipe consisting of a good drain pipe and a protective pipe, so that the drain pipe can be laid safely, accurately and easily, the laying period can be shortened, and the laying cost can be reduced. Therefore, the method has a high industrial applicability as a drain pipe laying method. [Explanation of symbols]

[0079] 11 Ground (natural ground) 12 Starting Shaft 13 Reaching shaft 14 Side drag 21 Propulsion tube 21a Insertion part 21b Reception Department 21c protrusion 21d Recess 22 Screw (male thread) 23 Screw (female thread) 24 Opening 25 Connection fittings 26a Connection part 26b Connection part 27a protrusion 27b Screw 31 Composite pipe 32 Cover 33 Fastening band 34 Bis 41 Drain pipe 42 Filter Material 43 Net body 44 Circular groove 45 Connection outer tube 46 Circular protrusion 47 Fastening band 48 Connection inner pipe 49 Locking claw 51 Protection tube 52a Male thread 52b Annular convexity 53a Female thread 53b Circular recess 54 Opening 61 Excavator (excavation machine) 62 Hydraulic Mechanism 63 Push Jack 64 Propulsion platform pushing part 65 Reaction wall 66 Pushing part 67 Bearing pipe 68 Substrate 69 Short tube 71 Retention Code 72 Holding plate 73 Holding plate 74 holes 75 holes 76 Moorings

Claims

1. By excavating the ground using an excavator, the ground between the starting shaft and the arrival shaft is excavated in the horizontal direction underground to form a horizontal tunnel extending from the starting shaft side to the arrival shaft side; and Pushing a jacking pipe into the adit and laying the jacking pipe over the entire length of the adit by pushing and intervening; and Removing the thrust pipe laid in the adit to the outside of the adit; and The adit is inserted through the adit several times over its entire length until the adit is free of undesirable roughness, irregularities, or steps on its inner diameter or inner peripheral surface. This is an adit excavation method characterized by the above.

2. 2. An adit excavation method as described in claim 1, wherein the adit is removed from the adit by pushing or pulling out the adit pipe laid in the adit from one end of the adit toward the arrival shaft.

3. 3. A method for excavating an adit according to claim 1, wherein a slippery material is interposed between the outer peripheral surface of the adit and the inner peripheral surface of the adit when the adit is pushed into the adit or when the adit is removed from the adit.

4. 4. The adit excavation method according to claim 1, wherein the thrust pipe is laid in the adit while the adit is being excavated.

5. A method for excavating an adit according to any one of claims 1 to 4, wherein the propulsion pipe laid in the adit is connected in the axial direction via a tubular connecting fitting so as to form a continuous tubular shape with no steps on the inner and outer peripheral surfaces of the connecting part.

6. 6. An adit excavation method according to claim 5, wherein said connecting fitting is detachable from said jacking pipe.

7. The horizontal shaft excavation method according to any one of claims 1 to 6, wherein the ground between the starting shaft and the arrival shaft is excavated horizontally underground from the starting shaft side to the arrival shaft side.

8. By excavating the ground using an excavator, the ground between the starting shaft and the arrival shaft is excavated in the horizontal direction underground to form a horizontal tunnel extending from the starting shaft side to the arrival shaft side; and Pushing a jacking pipe into the adit and laying the jacking pipe over the entire length of the adit by pushing and intervening; and Removing the thrust pipe laid in the adit to the outside of the adit; and The adit is inserted into the adit several times over the entire length until the adit is free of undesirable roughness, irregularities, or steps on its inner diameter or inner peripheral surface; and Laying a composite pipe having a drain pipe located relatively inside and a protective pipe located relatively outside over the entire length of the adit A pipe laying method characterized by the above.

9. By excavating the ground using an excavator, the ground between the starting shaft and the arrival shaft is excavated in the horizontal direction underground to form a horizontal tunnel extending from the starting shaft side to the arrival shaft side; and Pushing a jacking pipe into the adit while excavating the adit, and laying the jacking pipe over the entire length of the adit by pushing the jacking pipe into the adit; and Removing the thrust pipe laid in the adit to the outside of the adit; and The adit is inserted into the adit several times over the entire length until the adit is free of undesirable roughness, irregularities, or steps on its inner diameter or inner peripheral surface; and Laying a composite pipe having a drain pipe located relatively inside and a protective pipe located relatively outside over the entire length of the adit; and By removing the protective pipe from the composite pipe laid in the adit to the outside of the adit, the drain pipe is left in the adit and laid over the entire length of the adit. A pipe laying method characterized by the above.

10. A pipe laying method as described in claim 8 or claim 9, in which the thrust pipe laid in the adit is removed from the adit by pushing or pulling out the thrust pipe from one end of the adit toward the arrival shaft.

11. A pipe laying method according to any one of claims 8 to 10, in which a slippery material is interposed between the outer peripheral surface of the thrust pipe and the inner peripheral surface of the adit when either or both of the time when the thrust pipe is pushed into the adit and the time when the thrust pipe is removed from the adit.

12. 12. A pipe-laying method according to claim 8, wherein the jacking pipe is laid in the adit while the adit is being excavated.

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