JP2012215026A - Method of constructing pipe roof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve workability in inserting pipes to a rock mass and construction precision in constructing a pipe roof.SOLUTION: Each of pipes 10 constituting a pipe roof 5 comprises plate-like members 13 on outer circumferential surfaces at both right and left sides of an upper portion thereof, respectively. When constructing the pipe roof 5, the plurality of pipes 10 are first inserted to a rock mass in such a manner that the plate-like members 13 of neighboring pipes 10 are confronted with each other with a predetermined clearance C1 interposed therebetween. A frozen soil layer 21 is next formed so as to cover above the predetermined clearance C1, in which the predetermined clearance C1 is such a clearance that the frozen soil layer 21 can be self-supported. A high-pressure water jet device is then used to remove sediment between the pipes 10 under the predetermined clearance C1, thereby forming a space 6a. Thereafter, concrete 34 is deposited within the space 6a partitioned by a mold frame 33 and the pipes 10 are connected with each other, thereby integrating the pipe roof 5.

Description

  The present invention relates to a method for constructing a pipe roof by inserting a plurality of pipes into a natural ground.

In the pipe roof construction method, generally, a large number of pipes are inserted into a natural ground continuously or at regular intervals, and a pipe roof (protective roof) is constructed by these pipes.
As a technique regarding the pipe roof construction method, for example, there is a technique described in Patent Document 1.

  Patent Document 1 describes that, in the pipe roof construction method, the pipe roof is constructed by engaging and connecting adjacent pipes with each joint portion, thereby suppressing sediment discharge from the gap between adjacent pipes. Has been.

Japanese Patent Laid-Open No. 10-37656

  However, in the pipe roof construction method as described in Patent Document 1, in order to construct a pipe roof by a large number of pipes acting as one body, the joint portion connecting the pipes is required to be united. The joint portion can have a complicated connection structure.

  In addition, when the joint part has a complicated connection structure, it may become difficult to insert the pipe due to the resistance of the joint part when inserting the pipe into the natural ground. Can be reduced.

  In addition, when a new pipe is inserted into a natural ground via a joint so as to be adjacent to an existing pipe, the inserted pipe interferes with the existing pipe via the joint in the pipe insertion direction. An error may occur and the construction accuracy may be reduced, and thus the function as a protective roof may be reduced.

  This invention makes it a subject to improve the workability | operativity at the time of pipe insertion to a natural ground, and to improve the construction precision at the time of pipe roof construction in view of such a real situation.

  Therefore, in the present invention, as a method of constructing a pipe roof by inserting a plurality of pipes in parallel to each other at a distance from each other, a pipe roof is provided in advance for each pipe and projects outward from each outer peripheral surface, and A step of inserting the pipe into the ground so that the plate-like member extending in the longitudinal direction of the pipe faces the plate-like member of the adjacent pipe with a gap of a predetermined interval, and covering the gap from above A step of forming a stratum having water-stopping property, a step of removing soil between the pipes below the gap to form a space, and a step of installing a reinforcing member for connecting the pipes in the space. ,including. Moreover, the said predetermined space | interval is an space | interval in which the formation which has water-stopper can become independent. Here, in the present invention, the “interval at which the stratum having water-stopper can stand by itself” means the stratum having the water-stopper located above the gap having the gap by its own weight or the self-weight of the stratum located further above. It means an interval that does not cause collapse.

  According to the present invention, the plate-like member provided in advance on the pipe inserted into the natural ground projects outward from the outer peripheral surface of the pipe and extends in the longitudinal direction of the pipe. As a result, the configuration of the outer periphery of the pipe can be made relatively simple, so that the drag received by the pipe when the pipe is inserted into the natural ground can be kept relatively low, thereby improving the workability when inserting the pipe. be able to.

  According to the invention, the pipe is inserted into the natural ground so that the plate-like members of each pipe face each other with a gap of a predetermined interval. Thereby, when inserting the pipe into the natural ground, for example, since the plate-like member of the pipe to be inserted does not contact the plate-like member of the existing pipe, the insertion direction of the pipe can be stabilized. The construction accuracy when constructing the pipe roof can be improved.

The figure which shows the communicating path constructed | assembled using the pipe roof construction method in one Embodiment of this invention AA sectional view of FIG. Diagram showing schematic configuration of pipe The figure which shows the construction method of the pipe roof (the 1) Figure showing the construction method of pipe roof (part 2) Figure showing the construction method of pipe roof (part 3) The figure which shows the construction method of the pipe roof (the 4) The figure which shows the method of excavation formation of the space under the pipe roof

  Embodiments of the present invention will be described below with reference to the drawings. Here, the construction of the pipe roof will be described by taking the construction of the communication path that connects the shaft and the tunnel as an example, but the construction is not limited to this.

FIG.1 and FIG.2 shows the communicating path constructed | assembled using the pipe roof construction method in one Embodiment of this invention.
The communication path 1 that is an underground structure is a communication path that connects the shaft 3 and the tunnel 4 that have been excavated and formed in advance below the ground 2 (the natural ground 20).

The vertical shaft 3 includes a rectangular excavation bottom surface 3a and an earth retaining wall 3b installed from the ground 2 to the excavation bottom surface 3a so as to surround the excavation bottom surface 3a.
The tunnel 4 formed by excavation and separating from the vertical shaft 3 in the horizontal direction has a rectangular cross section. Further, the distance from the ground 2 to the bottom surface 4a of the tunnel 4 substantially matches the depth of the shaft 3 (that is, the distance from the ground 2 to the excavation bottom surface 3a).

  The communication path 1 is a communication path having a rectangular cross section, one end of which communicates with the shaft 3 through a through hole 3 c formed through the retaining wall 3 b of the shaft 3, while the other end is a side wall of the tunnel 4. It communicates with the tunnel 4 through a through-hole 4c formed through 4b. In addition, the distance from the ground 2 to the bottom surface 1a of the communication path 1 includes the distance from the ground 2 to the bottom surface 4a of the tunnel 4 and the depth of the shaft 3 (that is, the distance from the ground 2 to the bottom surface 3a of the excavation). It is almost coincident.

Prior to the construction of the communication path 1, a pipe roof (protective roof) 5 is constructed above it. That is, the communication path 1 is constructed below the pipe roof 5.
The construction method of the communication path 1 includes, for example, the following four steps.
(1) The pipe roof 5 is constructed so as to cover the communication path 1 above the position where the communication path 1 is to be constructed.
(2) In parallel with the construction of the pipe roof 5 and / or after the construction of the pipe roof 5, a space 6 for constructing the communication path 1 is excavated and formed below the pipe roof 5.
(3) The communication path 1 is constructed in the space 6. The communication path 1 is configured by, for example, a box culvert.
(4) For example, fluidizing soil 7 is filled in a space outside the communication path 1 in the space 6 to refill the space.

Next, the construction method of the pipe roof 5 will be described with reference to FIGS. 3 to 7 in addition to FIGS. 1 and 2.
FIG. 3 is a diagram showing a schematic configuration of the pipe 10 constituting the pipe roof 5. 4 to 7 are enlarged views of a portion corresponding to the portion B in FIG.

  The pipe 10 is a steel pipe having a circular cross section, and the length in the longitudinal direction is longer than the length in the longitudinal direction of the communication path 1 as shown in FIG. Therefore, after inserting the pipe 10 into the natural ground 20, one end of the pipe 10 can be positioned above the tunnel 4.

  As shown in FIG. 3, the pipe 10 is provided with a plurality of (for example, two) deformed steel bars 11 on the left and right outer peripheral surfaces. The deformed steel bar 11 extends along the longitudinal direction of the pipe 10 and is welded to the pipe 10.

  Freezing pipes 12 are provided on the left and right sides of the upper part of the pipe 10. A refrigerant can be flowed into the freezing tube 12 by a pump or the like (not shown). Here, as an example of the refrigerant, an antifreeze such as salt water can be cited.

  Plate members (for example, steel plates) 13 are provided on the outer peripheral surface of the pipe 10 in the vicinity of the freezing pipes 12 on the left and right sides, respectively. The plate members 13 on both the left and right sides respectively project outward from the outer peripheral surface of the pipe 10 in the lateral direction, extend along the longitudinal direction of the pipe 10, and are welded to the pipe 10. The plate-like member 13 projects laterally from the outer peripheral surface of the pipe 10 along the pipe parallel direction described later.

In the present embodiment, a plurality of pipes 10 (for example, 10 pipes) are used, and these pipes 5 are inserted into the natural ground 20 in parallel with a space between each other to construct the pipe roof 5.
In the construction of the pipe roof 5, the steps shown in FIGS. 4A to 7H are performed not only in the portion B in FIG. 2 but also in portions other than the portion B in the same manner as the portion B. To do.

  When constructing the pipe roof 5, first, as shown in FIGS. 1, 2, and 4 (a), a plurality of pipes 10 are sequentially inserted into the natural ground 20 from the shaft 3 (the retaining wall 3 b). The plurality of pipes 10 are installed in an arch shape so as to cover the communication path 1 above the position where the communication path 1 is to be constructed. In other words, the plurality of pipes 10 are arranged in an arch shape in a direction substantially perpendicular to the longitudinal direction. Here, the arrangement direction of the pipes 10 arranged in parallel in the arch shape corresponds to the pipe parallel direction in the present invention.

  When the pipe 10 is inserted into the natural ground 20, as shown in FIG. 4A, the plate-like member 13 of the pipe 10 faces the plate-like member 13 of the adjacent pipe 10 with a gap of a predetermined interval C1. Thus, the pipe 10 is inserted into the natural ground 20. Here, the predetermined interval C1 is an interval at which the frozen ground layer 21 shown in FIG. The interval at which the frozen soil layer 21 can stand on its own is an interval at which the frozen soil layer 21 located above the gap having the interval does not collapse due to its own weight or the weight of the formation located further above. Further, the gap having the predetermined interval C <b> 1 is located in the center portion between the pipes 10.

When the insertion of the pipe 10 into the natural ground 20 is completed, the internal space 10a of the pipe 10 is filled with mortar as a filler.
Next, when a refrigerant is passed through the freezing pipe 12, the surrounding ground is frozen through the pipe 10 and the plate-like member 13 in the vicinity of the freezing pipe 12 to form a frozen soil layer 21 as shown in FIG. Is done. Thereby, since at least the upper part of the gap having the predetermined interval C1 is covered with the frozen soil layer 21, the water stoppage in the gap can be ensured. Therefore, the frozen soil layer 21 can function as a formation having water-stopping property in the present invention. In addition, about the formation which has a water stop in this invention, it should just be able to hold | maintain a water stop at the time of construction of the pipe roof 5 at least temporarily.

  In this way, by forming a stratum having a water-stopping property on the entire pipe roof 5, a stratum having a water-stopping property is formed on the entire upper portion of the pipe roof 5. Water can be done. In addition, the formation method of the formation which has a water-stopping property is not restricted to the method by the above-mentioned freezing. For example, instead of forming a frozen soil layer, it is possible to form a stratum having a water-stopping property by so-called ground improvement. In this ground improvement, for example, piping for chemical solution injection is provided in the pipe 10 in advance, and water is stopped by chemical solution injection above the pipe roof 5 including the upper portion of the gap having a predetermined interval C1. It is possible to form a formation. Moreover, in this ground improvement, it is also possible to form a stratum having waterstop above the pipe roof 5 including the upper part of the gap having the predetermined interval C1 by using a so-called high-pressure jet stirring method.

Next, as shown in FIG. 5 (c), a portion of the space 6 for constructing the communication path 1 is formed by excavating the lower part of the pipe roof 5. The method for forming the space 6 will be described later with reference to FIG.
Next, as shown in FIG. 5 (d), the earth and sand 20 a below the frozen soil layer 21 between the pipes 10 is removed using the high-pressure water injection device 30.

  The high-pressure water injection device 30 includes a cylindrical injection arm 31 and an injection head 32 that is rotatably attached to the tip of the injection arm 31 and injects high-pressure water (for example, about 250 MPa).

The ejection head 32 is rotatable with respect to the ejection arm 31 with the longitudinal axis of the ejection arm 31 as a central axis.
The ejection head 32 is provided with two types of ejection nozzles including a first ejection nozzle 32a and a second ejection nozzle 32b.

  The plurality of first injection nozzles 32 a are attached to the tip of the injection head 32 and can inject high-pressure water in a direction inclined by a predetermined angle (for example, about 45 °) with respect to the longitudinal direction of the injection arm 31. . Therefore, when the ejection head 32 is rotated, high-pressure water ejection from the first ejection nozzle 32a can realize a substantially conical high-pressure water ejection that increases in diameter from the tip of the ejection head 32 in the ejection direction.

  On the other hand, the plurality of second ejection nozzles 32 b are respectively attached to the base end portion of the ejection head 32, and have a high pressure in a direction slightly inclined toward the ejection head distal side from a direction substantially perpendicular to the longitudinal direction of the ejection arm 31. Each of the water can be jetted.

  When removing the earth and sand 20a between the pipes 10, high pressure water injection is started with the tip of the jet head 32 facing the earth and sand 20a to be removed below the earth and sand 20a to be removed, and the jet head 32 is rotated. The earth and sand 20a is removed by gradually raising the jet arm 31 and the jet head 32.

  The high-pressure water from the first injection nozzle 32 a is removed by stirring so that the earth and sand 20 a between the pipes 10 is wound from the vicinity of the pipes 10 to the central part between the pipes 10. Therefore, since it can suppress that the high pressure water from the 1st injection nozzle 32a collides with the earth and sand of the center part between pipes 10 directly, the water pressure which acts on the center part between pipes 10 can be suppressed.

On the other hand, the high-pressure water from the second injection nozzle 32b cleans the surface of the pipe 10.
After removing the earth and sand 20a, as shown in FIG. 6 (e), the frozen soil 21a between the pipes 10 below the gap having the predetermined interval C1 is removed using the high-pressure water injection device 30. This removal of frozen soil is the same as the removal of the earth and sand 20a shown in FIG. Note that, by setting the high-pressure water jetted from the first jet nozzle 32a to a relatively low flow rate, melting of frozen soil in the vicinity of the gap having the predetermined interval C1 is suppressed. For removing the frozen soil, as shown in FIG. 6 (f), the injection arm 31 and the injection are performed until the injection direction of the high-pressure water from the first injection nozzle 32 a is close to the welded portion between the pipe 10 and the plate-like member 13. The process ends when the head 32 is raised.

  The removal of the earth and sand 20a and the frozen soil 21a between the pipes 10 shown in FIGS. 5 (d) to 6 (f) is performed not only in the portion B (see FIG. 2) of the pipe roof 5, but also in the pipe roof 5. Among them, the portion other than the portion B is carried out in the same manner as the portion B, and a space 6a for reinforcing member installation is secured between the pipes 10 as shown in FIG.

Next, as shown in FIG. 7 (h), the mold 33 is installed below the pipe roof 5.
Thereafter, concrete 34 is placed in the space 6 a defined by the mold 33.
The concrete 34 functions as a reinforcing member in the present invention, and has a function of connecting the pipes 10 together. In this embodiment, the concrete 34 is used as the reinforcing member. However, the reinforcing member is not limited to this, and the reinforcing member may be, for example, mortar.

  When the concrete 34 is consolidated (in other words, when a reinforcing member is installed in the space 6a), the pipes 10 are integrated. At this time, the deformed steel bar 11 provided on the outer peripheral surface of the pipe 10 exhibits the function of a gibber, and the concrete 34 and the pipe 10 are reliably integrated. Further, since the surface of the pipe 10 is washed with the high-pressure water from the second injection nozzle 32b, the concrete 34 is in good contact with the surface of the pipe 10, so that the integrity of the concrete 34 and the pipe 10 is further improved. be able to. The formwork 33 may be removed after the concrete 34 is consolidated, or may be embedded as it is.

FIG. 8 shows a method of excavating the space 6 below the pipe roof 5.
First, as shown in FIG. 8A, excavation is performed from the shaft 3 side toward the axial direction of the pipe roof 5 (longitudinal direction of the pipe 10) (that is, toward the left side in the figure), and a predetermined distance is set. After excavation to form a part of the space 6 shown in FIG. 5C, the pipe roof 5 is integrated as shown in FIGS. 5D to 7H. In the example of FIG. 8A, the pipe roof 5 having a length D that has been excavated and exposed is integrated. At this time, the remaining length E of the pipe roof 5 is buried in the soil, and the pipe roof 5 of the E portion is supported by the soil.

  Next, as shown in FIG. 8B, the lower part of the pipe roof 5 is excavated in the axial direction of the pipe roof 5 (in the direction of arrow G in the figure). In the example of FIG. 8B, the lower portion of the pipe roof 5 is excavated by a distance F. In the excavated state, the pipe roof 5 is already integrated in the D portion, so that the so-called arch effect is exerted, and the earth pressure from above can be handled. On the other hand, since the load is supported by the soil in the E portion buried in the soil, the earth and sand do not collapse. Accordingly, the pipe roof 5 is not integrated only in the range of the length F, and the earth pressure from above cannot be supported by the lower earth and sand.

  That is, until the pipe roof 5 exposed at the F portion after the excavation is integrated, the earth pressure from the upper portion of the F portion is handled by the D portion and the E portion. Therefore, it is possible to excavate only the range (length F) that can be supported by the D part and the E part.

  When the pipe roof 5 of the F part in FIG. 8B is integrated (that is, when the F part becomes the D part), the same procedure is repeated so that the lower part of the pipe roof 5 extends in the axial direction of the pipe roof 5. The pipe roof 5 is integrated by digging by length F. While repeating the above steps, a space 6 below the pipe roof 5 is formed by excavation, and the communication path 1 is constructed in the space 6.

Next, the operation in this embodiment will be described.
In general, when a pipe is inserted into a natural ground, a phenomenon called ambient softening in which the ground around the pipe softens may occur. Moreover, when inserting a pipe into a natural ground, the pipe has a property that it is easy to face a softened ground. For this reason, when a new pipe is inserted into the ground so as to be adjacent to the existing pipe, the newly inserted pipe is not affected by the surrounding softening phenomenon that occurs when the existing pipe is inserted and the softened ground. Due to the nature of being easy to face, there may occur a phenomenon in which the pipes are arranged closer to each other than planned, a phenomenon in which a newly inserted pipe rotates, or the like. Therefore, if the plate-like members of adjacent pipes are overlapped with each other (by overlapping), the pipes are arranged close to each other in order to ensure water-stopping from the upper side to the lower side of the pipe roof. Due to the phenomenon and the phenomenon of the newly inserted pipe rotating, the overlapping plate-like members may be stuck together and may not move, and the plate-like member may be damaged.

  In this regard, according to the present embodiment, the pipe 10 is placed on the natural ground 20 so that the plate-like member 13 of each pipe 10 faces the plate-like member 13 of the adjacent pipe 10 with a gap of a predetermined interval C1. insert. For this reason, since possibility that the plate-shaped members 13 will contact at the time of insertion of the pipe 10 to the natural ground 20 can be reduced, the fall of workability | operativity resulting from the contact between the plate-shaped members 13 is suppressed. In addition, damage to the plate-like member 13 can be suppressed.

  According to the present embodiment, the plate-like member 13 provided in advance in the pipe 10 to be inserted into the natural ground 20 projects outward from the outer peripheral surface of the pipe 10 in the lateral direction and extends in the longitudinal direction of the pipe 10. . Thereby, since the structure of the outer peripheral part of the pipe 10 can be made comparatively simple, the drag received by the pipe 10 when the pipe 10 is inserted into the natural ground 20 can be kept relatively low. Workability at the time of insertion can be improved.

  Further, according to the present embodiment, the pipe 10 is inserted into the natural ground 20 so that the plate-like member 13 of each pipe 10 faces the plate-like member 13 of the adjacent pipe 10 with a gap of the predetermined interval C1. . Thereby, when the pipe 10 is inserted into the natural ground 20, for example, the plate-like member 13 of the pipe 10 to be inserted does not contact the plate-like member 13 of the existing pipe 10. As a result, the construction accuracy when constructing the pipe roof can be improved.

  Moreover, according to this embodiment, the predetermined space | interval C1 is a space | interval which the stratum (frozen soil layer 21) which has water-stopper can become independent. Thereby, since it becomes unnecessary to overlap the plate-like members 13 of the adjacent pipes 10 to ensure water-stopping, it is possible to suppress a decrease in workability due to contact between the plate-like members 13, and Damage to the plate-like member 13 can be suppressed.

  Moreover, according to this embodiment, high pressure water is sprayed to the earth and sand 20a and the frozen earth 21a using the 1st injection nozzle 32a, and the earth and sand 20a and the frozen earth 21a are removed. Thereby, even the earth and sand 20a and the frozen earth 21a between the comparatively narrow pipes 10 can be removed satisfactorily.

  Further, according to the present embodiment, the high pressure water is sprayed obliquely upward from below the gap having the predetermined interval C1 between the pipes 10 using the first spray nozzle 32a to remove the earth and sand 20a and the frozen soil 21a. Thereby, since it can suppress that the high pressure water from the 1st injection nozzle 32a collides directly with the frozen soil near the gap | interval which has the predetermined space | interval C1, the water pressure which acts on the frozen soil near the said gap is suppressed. Can do.

  Further, according to the present embodiment, the stratum having waterstop is the frozen soil layer 21. Thereby, after the pipe roof 5 is integrated by the concrete 34 or the like, the frozen soil layer 21 returns to the original ground, so that it is possible to reduce the environmental load during the construction of the pipe roof.

  Further, according to the present embodiment, the plate-like member 13 projects from the outer peripheral surface of the pipe 10 so as to follow the pipe parallel direction. As a result, the frozen soil layer 21 covering the gap of the predetermined interval C1 from above can be formed along the pipe parallel direction, so that the frozen soil layer 21 can be formed substantially uniformly above the pipe roof 5. Moreover, the concrete 34 which is a reinforcement member can be formed using the plate-shaped member 13 as a partition plate. Furthermore, the concrete 34 formed in a smooth shape along the plate-like member 13 can form an arch integrally with the pipe 10.

  In the present embodiment, the earth and sand 20a and the frozen earth 21a are removed by jetting the high-pressure water onto the earth and sand 20a and the frozen earth 21a. You may comprise so that air may be injected.

Moreover, in this embodiment, although the pipe 10 has a circular cross section, the cross-sectional shape of the pipe 10 is not restricted to this, For example, the pipe 10 may have a rectangular cross section.
In the present embodiment, the plurality of pipes 10 are arranged in an arch shape in a direction substantially perpendicular to the longitudinal direction, but the arrangement shape of the pipes 10 is not limited to the arch shape. It is also possible to adopt a gate shape as the shape.

  In the present embodiment, the construction of the pipe roof 5 has been described by taking the construction of the communication passage 1 that connects the shaft 3 and the tunnel 4 as an example. However, the underground structure constructed below the pipe roof 5 is the communication passage 1. For example, the pipe roof construction method according to the present invention can be applied to a structure constructed between a pair of tunnels as an underground structure constructed below the pipe roof 5. .

1 communication path 1a bottom 2 ground 3 shaft 3a excavation bottom (bottom bottom)
3b Earth retaining wall 3c Through hole 4 Tunnel 4a Bottom surface 4b Side wall 4c Through hole 5 Pipe roof (protective roof)
6, 6a space 7 fluidized soil 10 pipe 10a internal space 11 deformed steel bar 12 freezing pipe 13 plate-like member 20 ground mountain 20a earth and sand 21 frozen soil layer 21a frozen soil 30 high pressure water injection device 31 injection arm 32 injection head 32a first injection nozzle 32b Second injection nozzle 33 Form 34 Concrete (reinforcing member)

Claims (5)

A method of constructing a pipe roof by inserting a plurality of pipes in parallel to each other at a distance from each other,
A plate-like member provided in advance for each pipe and projecting outward from each outer peripheral surface and extending in the longitudinal direction of the pipe is opposed to the plate-like member of the adjacent pipe with a predetermined gap. In addition, the process of inserting the pipe into the natural ground,
Forming a water-bearing formation so as to cover the gap from above;
Removing the soil between the pipes below the gap to form a space;
In this space, a step of installing a reinforcing member for connecting pipes;
Including
The method for constructing a pipe roof, wherein the predetermined interval is an interval at which the formation having the water-stopping property can stand on its own.   2. The method for constructing a pipe roof according to claim 1, wherein the earth and sand are removed by jetting high-pressure water and / or high-pressure air onto the earth and sand when the earth and sand are removed.   3. The pipe roof construction method according to claim 2, wherein the earth and sand are removed by spraying the high-pressure water and / or high-pressure air obliquely upward from below the gap between the pipes.   The construction method for a pipe roof according to any one of claims 1 to 3, wherein the water-resistant formation is a frozen soil layer.   5. The method for constructing a pipe roof according to claim 1, wherein the plate-like member projects from the outer peripheral surface of the pipe so as to follow the pipe parallel direction.