JP2018031159A - Construction method of underground structure - Google Patents

Abstract

A method for constructing an underground structure in which an underground structure is constructed near a hollow underground structure, such as an existing tunnel, in a direction orthogonal to the hollow underground structure, and the hollow underground structure is lifted by buoyancy. It is a face excavation with excavator etc. from the ground in front of the face instead of the concrete box (in the tunnel), and the tunnel work becomes the ground work, so the workability is good and the construction environment of the excavation work is Since the construction environment is good and the construction environment is good, the construction period is shortened, and the shortening of the construction period shortens the buoyancy generation period and improves the buoyancy prevention effect. The earth and sand left above the existing underground structure is excavated by the excavator 20 from the ground in front of the face. [Selection] Figure 1

Description

  The present invention relates to a method for constructing a new underground structure above an existing hollow underground structure buried in the ground.

The following patent documents show that when a new underground structure is built near a hollow underground structure such as an existing tunnel or other underground structure, an auxiliary measure is not required and the existing underground structure is low-cost. Proposed a method for constructing underground structures that can prevent buoys from rising, and obtained a patent.
Japanese Patent No. 4131187

  As shown in FIG. 3, this is a method for constructing an underground structure in which an underground structure is constructed at a position close to a direction perpendicular to the hollow underground structure above a hollow underground structure such as an existing tunnel. A start shaft and a reach shaft are built on both sides of the hollow underground structure, and at least above the existing hollow underground structure is at least high enough to prevent the hollow underground structure from rising due to buoyancy. Necessary for the existing hollow underground structure by excavating the earth and sand, moving the newly constructed underground structure horizontally from the start shaft to the arrival shaft, and gradually removing the remaining sediment at the location. By installing this new underground structure above the existing hollow underground structure while substituting it with the earth and sand so that a continuous load acts continuously, the existing sand and sand left above the existing hollow underground structure is installed. Hollow basement Is intended to go gradually replaced the underground structure that established the load required for the anti-surfacing by the buoyancy of the thing.

  In the basement, hollow underground structures such as tunnels, underground passages, and common grooves are buried, but for example, with a concrete box in a form that crosses the road to the adjacent position above the existing tunnel that is an existing hollow underground structure When constructing a new underground structure, or when constructing a new underground structure with a concrete box in the form of crossing the railway near the upper side of the existing tunnel, excavation by the open-cut method will be performed on the excavated part. If a new concrete box was hung from the opening on the surface of the ground and installed, the load from the upper side of the existing tunnel is reduced and the existing tunnel is reduced. On the other hand, large buoyancy acts, causing problems such as the existing tunnel floating and the surrounding ground rising.

  Therefore, in order to prevent the existing hollow underground structure such as the existing tunnel 1 from rising, the problem can be solved by demolishing or removing the existing hollow underground structure for a period of time. In addition, a great influence such as the suspension of use of the existing hollow structure in the meantime occurs, and it is necessary to secure a site separately, and the cost is also required.

  Since the said patent document 1 solves such a problem, since it does not excavate by an open-cut method, it is not necessary to take an auxiliary measure, and immediately before a newly installed underground structure is installed, the sediment above the existing underground structure is Since the new underground structure is installed without excavation and replaced with earth and sand, the existing underground structure is not lifted by buoyancy until the new underground structure is installed.

  Moreover, since the start shaft and the reaching shaft are built on both sides of the existing underground structure, there is no possibility that these shafts will affect the existing hollow underground structure and cause buoyancy in the structure.

  In general, the tunnel excavation including Patent Document 1 is performed in a tunnel. In the case of Patent Document 1 as well, in order to propel the concrete box 2 from the start shaft 9 toward the arrival shaft 10, the box propulsion works by excavating the face from the concrete box 2 to construct the concrete box 2 in the existing tunnel. 1 is advanced.

  For this reason, it takes a considerable amount of time to stabilize the face normally and to perform excavation, earth and sand removal, and earth retaining.

  The object of the present invention is to eliminate the inconvenience of the conventional example, and the face excavation in the tunnel is not necessarily in the tunnel, but the face excavation is performed with the excavator from the ground in front of the face, so that the construction environment of the excavation work is improved. As a result, an object of the present invention is to provide an underground structure construction method that can shorten the construction period.

  In order to achieve the above object, the present invention according to claim 1 is directed to an underground structure for constructing an underground structure in a proximity position in a direction orthogonal to the hollow underground structure above a hollow underground structure such as an existing tunnel. In the construction method, a start shaft and a reach shaft are built on both sides of the existing hollow underground structure, and at least the hollow underground structure can be prevented from rising due to buoyancy above the existing hollow underground structure. Excavation of the earth leaving the earth and sand, and moving the newly constructed underground structure horizontally from the starting shaft to the arrival shaft, gradually removing the remaining earth and sand at the location, By replacing this earth and sand with the newly installed underground structure above the existing hollow underground structure so that the load necessary to prevent buoyancy acts constantly on the underground structure, the existing hollow underground structure Left above In the construction method of the underground structure that gradually replaces the load necessary to prevent levitation due to buoyancy to the existing hollow underground structure with the earth and sand that was newly installed, it was left above the existing underground structure The excavation of earth and sand is to excavate the face with an excavator from the ground in front of the face.

  According to the first aspect of the present invention, since excavation is not performed by the open-cut method, the earth and sand above the existing underground structure is not excavated and replaced with earth and sand until just before the newly installed underground structure is installed. The existing underground structure will not be lifted by buoyancy until the newly installed underground structure is installed.

  Moreover, since the start shaft and the reaching shaft are built on both sides of the existing underground structure, there is no possibility that these shafts will affect the existing hollow underground structure and cause buoyancy in the structure.

  Furthermore, it is a face excavation by an excavator or the like from the ground in front of the face rather than the concrete box (inside the tunnel), and the tunnel work becomes the ground work, so the workability is good and the construction environment of the excavation work is good.

  Because the construction environment is good, the construction period is shortened, and shortening the construction period shortens the buoyancy generation period and improves the buoyancy prevention effect.

  The gist of the present invention described in claim 2 is that the top end of the newly constructed structure is higher than the shallow earth covering or the ground surface.

  According to the second aspect of the present invention, the top end of the newly constructed structure is higher than the shallow earth covering or the ground surface, thereby facilitating face excavation with an excavator or the like from the ground in front of the face. It can be carried out.

  As described above, the construction method of the underground structure according to the present invention uses the open-cut method when constructing a newly installed underground structure near a hollow underground structure such as an existing tunnel or other underground structure. First, leave the earth and sand above the existing underground structure, excavate this earth and sand, replace the earth and sand, move the new underground structure from the start shaft to the destination shaft, and move above the existing underground structure. Since a new underground structure is installed in the building, no auxiliary measures are required, it is possible to prevent the existing underground structure from rising at a low cost, the construction period is not prolonged, and construction can be performed safely. it can.

  In addition, it is face excavation by excavator etc. from the ground ahead of the face rather than the concrete box (inside the tunnel), and the tunnel work becomes ground work, so the workability is also good and the excavation work environment is good, Since the environment is good, the construction period is shortened, and shortening the construction period shortens the buoyancy generation period and improves the buoyancy prevention effect.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal side view showing an embodiment of a construction method for an underground structure of the present invention. However, an underground structure constructed by the construction method of the present invention will be described first. As shown in FIG. For example, a concrete box 2 that is a newly installed underground structure is installed near the upper position of the existing tunnel 1 as a hollow underground structure, and the existing tunnel 1 is embedded in the underground ground of the road 16. .

  Excavation is carried out by a depth h1 from the road surface of the road 16 so that earth and sand for a height h remain above the existing tunnel 1, and the height h only prevents the existing tunnel 1 from being lifted by buoyancy. The amount of earth and sand with a load of.

  As shown in FIG. 2, temporary earth retaining piles 4 are driven on both sides of the existing tunnel 1 at a position where buoyancy does not act on the existing tunnel 1, and two spaces between the temporary earth retaining piles 4, 4 are provided. Next, the start shaft 9 and the arrival resistance 10 are constructed by excavation.

  At this time, the earth and sand for the height h are still left above the existing tunnel 1, and the existing tunnel 1 will not be lifted by buoyancy even if the starting shaft 9 and the reaching shaft 10 are built around. And the start stand 11 is built in the start shaft 9.

  A bearing wall 12 as a reaction force facility is installed in the start shaft 9, and a concrete box 2 as a new underground structure is arranged, or the concrete box 2 is built in the start shaft 9, The blade edge 13 is assembled at the front of the concrete box 2.

  The blade edge 13 is made of a steel plate and is attached so as to protrude forward from the front end of the concrete box 2. In this embodiment, the shape is a U-shape of a bottom plate and a side plate, and there is no horizontal shelf. In addition, the protrusion length of the side plate was changed stepwise up and down.

  Then, propulsion equipment such as a push jack 14 is installed between the rear portion of the concrete box 2 and the bearing wall 12.

  In this way, the concrete box 2 is propelled from the starting shaft 9 toward the reaching shaft 10.

  The construction of this embodiment is not a railroad or a road crossing but a construction on a flat ground, and the top of the concrete box 2 is a shallow earth cover or a case where it is higher than the ground road surface.

  The ground road surface may be excavated in advance, and primary excavation may be performed so as to be lowered in advance, and the board may be lowered.

  The concrete box 2 is propelled from the starting shaft 9 toward the reaching shaft 10. In this box propulsion work, the face is excavated by the excavator 20 from the ground in front of the face. As the excavator 20, a backhoe type shovel excavator is optimal, and excavates with the excavation bucket 20b at the tip of the arm 20a.

  Then, although the excavated concrete box 2 is propelled, the excavator 20 can move along with the propulsion of the concrete box 2.

  In this way, the succeeding concrete box 2 is manufactured in the start shaft 9 behind the leading concrete box 2, and connected to the leading concrete box 2 and the succeeding concrete box 2 while excavating the face. Further promote.

  The box body propelling work of the present invention is to push the concrete box 2 to the upper adjacent position of the existing tunnel 1 while excavating the face. By replacing the earth and sand with the concrete box 2, the upper part of the existing tunnel 1 is applied. Do not reduce the load.

  As a result, a constant load is always applied to the existing tunnel 1 from above, and the existing tunnel 1 will not be lifted by buoyancy even when excavating above the existing tunnel 1.

  When the leading edge 13 of the concrete box 2 reaches the reach shaft 10, the concrete box 2 is completely propelled, and the new concrete box 2 is installed at a position close to the upper side of the existing tunnel 1.

  In the above-described embodiment, the concrete box 2 is pushed and propelled by using a main push jack installed on the start shaft 9 side as a forward means of the new concrete box 2, but the invention is not limited to this. If it is a mechanism which can move the concrete box 2 horizontally, the new concrete box 2 can also be pulled and advanced from the reach shaft 10 side using the pulling equipment installed in the reach shaft 10 side.

  In the above, the case of a hollow underground structure such as an existing tunnel has been shown as the existing underground structure, but the present invention in the case of a building or other underground structure other than a hollow well can be similarly applied.

It is a vertical side view which shows one Embodiment of the construction method of the underground structure of this invention. It is a vertical side view of the front process which shows one Embodiment of the construction method of the underground structure of this invention. It is a vertical side view which shows a prior art example. It is an assumption figure in the case of constructing a new underground structure above an existing hollow underground structure.

DESCRIPTION OF SYMBOLS 1 ... Existing tunnel 2 ... Concrete box 3 ... Construction girder 4 ... Temporary earth retaining pile 5 ... Ground anchor 6 ... Lifting prevention material 7 ... Vertical shaft 8 ... Foundation pile 9 ... Starting shaft 10 ... Reaching shaft 11 ... Start stand 12 ... Support Pressure wall 13 ... Blade 14 ... Presser jack 15 ... Strut 16 ... Road 20 ... Excavator 20a ... Arm 20b ... Drilling bucket

Claims (2)

  In the construction method of an underground structure in which an underground structure is constructed near a hollow underground structure, such as an existing tunnel, in a direction perpendicular to the hollow underground structure, on both sides of the existing hollow underground structure, A start shaft and a reaching shaft will be constructed, and at the upper part of the existing hollow underground structure, at least this hollow underground structure will be excavated with a sufficient height to prevent the hollow underground structure from rising due to buoyancy. While moving the underground structure horizontally from the start shaft to the arrival shaft, the remaining earth and sand is gradually removed, and the load necessary to prevent buoyancy is constantly acting on the existing hollow underground structure. Thus, by replacing this earth and sand with the newly installed underground structure above the existing hollow underground structure, the existing hollow underground structure with the earth and sand left above the existing hollow underground structure is installed. Buoyancy In the construction method of the underground structure that gradually replaces the load necessary to prevent levitation with the newly installed underground structure, the earth and sand left above the existing underground structure is excavated from the ground in front of the face. Construction method of underground structure characterized by excavating face at   The method for constructing an underground structure according to claim 1, wherein the top end of the newly constructed structure is higher than the shallow earth covering or the ground surface.

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