JP5729712B1 - Earth retaining method and earth retaining unit - Google Patents

Abstract

The present invention provides a safe earth retaining method that more reliably prevents the excavation groove from collapsing in the excavation work in which a predetermined construction work is performed on a construction space adjacent to the excavation groove while excavating the excavation groove. A earth retaining method for performing a predetermined construction work on a construction space 34 adjacent to the excavation groove 3 while excavating the excavation groove 3 from the ground surface 30, wherein the excavation wall surface of the excavation groove 3 is provided. Among them, a soil retaining unit having a retaining wall covering three surfaces excluding the construction surface 10 facing the construction space 34 is set in the excavation groove 3 as the excavation progresses, and the soil from three surfaces other than the construction surface 10 is deposited by the soil retaining unit. While supporting the pressure P, construction work is performed on the construction space 34 from within the excavation groove 3. [Selection] Figure 5

Description

  The present invention performs a predetermined construction work on a construction space adjacent to the excavation groove while opening the excavation groove for work from the ground surface, for example, when laying a pipe with a gas pipe or a water and sewage pipe in the ground. It is related with the earth retaining method in the open-cutting civil engineering work to be performed, and the earth retaining unit used therefor.

  Conventionally, when laying pipes such as gas pipes, oil pipes, water and sewage pipes, protective pipes for power transmission cables, telephone lines, and optical fiber cables for communication in the ground, excavating the laying grooves by excavation from the ground In many cases, a so-called open-cut method is employed in which pipes are laid, joined, inspected, and subjected to anticorrosion work and then backfilled with backfill soil.

  In order to prevent the side walls of the excavated excavation groove from collapsing during the construction period from this excavation to backfilling, for example, a steel sheet pile is driven along the side of the excavation groove, and then the abdominal erection and cutting beam etc. The support works were placed at predetermined intervals to hold earth against earth pressure. Then, after performing a series of laying operations, the cut beams, upsets, sheet piles, and the like are sequentially removed while the excavation groove is backfilled. Thereby, the earth pressure from the wall surface of the excavation groove is supported, the collapse of the excavation surface can be prevented, and the safety of the work in the excavation groove can be ensured (for example, Patent Document 1).

Japanese Patent Laid-Open No. 10-114946

  By the way, for example, in the above-described piping laying work or maintenance work such as inspection, as shown in FIG. 7, the branch pipe 35a is taken out from the previously buried main pipe 33, or the surrounding piping is removed. There is a case where a narrow portion such as the branch pipe 35b is buried while the regulation by 35b or the like is avoided. In this case, it is necessary to excavate the cut groove 3 so as not to interfere with the existing structure or to perform construction on the construction surface 32a, and the earth retaining material such as the sheet pile as described above is sufficiently embedded in the ground. There are cases where it is not possible to do this. In particular, in a ground where existing structures are arranged in a complex manner such as an urban area, concrete 33a is applied to all (360 °) or a part (eg, 90 ° to 180 °) of the outer peripheral surface of the main pipe 33. There are times when it is installed and protected, and in such a case, it is not possible to drive the earth retaining material into the concrete 33a portion. Even if it is driven in avoiding this, excavation and backfilling are repeated many times on the ground around the existing structure, and the ground is soft and sufficient embedding depth cannot be secured. However, there is a problem that the soil retaining effect cannot be obtained.

  Therefore, the present invention solves the above problems, and more reliably when performing a predetermined construction work on a construction space adjacent to the excavation groove while excavating the excavation groove for work from the ground surface. It is another object of the present invention to provide a soil retaining method capable of preventing the collapse of excavation grooves and realizing safe civil engineering work, and a soil retaining unit used therefor.

In order to solve the above problems, the present invention is a earth retaining method when performing a predetermined construction work on a construction space adjacent to the excavation groove while excavating the excavation groove for work from the ground surface,
(1) A step of sinking a soil retaining unit having a retaining wall covering three surfaces excluding the construction surface facing the construction space in the excavation groove in the excavation groove as the excavation progresses;
(2) a step of projecting the support leg from the soil retaining unit toward the construction surface direction, obtaining a reaction force from the excavation surface on the construction surface side, and supporting the soil retaining unit;
(3) A process of performing construction work on the construction space from within the excavation groove while supporting earth pressure from three sides by the earth retaining unit.

Further, another invention is a soil retaining unit used in a soil retaining method when performing a predetermined construction work on a construction space adjacent to the excavation groove while excavating the excavation groove for work from the ground surface,
Of the excavation wall of the excavation groove, a horizontal wall covering the three surfaces excluding the construction surface facing the construction space is a U-shaped retaining wall,
And a supporting leg that protrudes from the retaining wall toward the construction surface, obtains a reaction force from the excavation surface on the construction surface side, and supports the retaining wall.

  According to these inventions, since the earth pressure from the three excavation surfaces excluding the construction surface is supported by the earth retaining wall of the earth retaining unit among the wall surfaces of the excavation groove, the excavation surface is prevented from collapsing and the work in the excavation groove is performed. Can be secured. At this time, since the construction surface of the soil retaining unit is open, operations such as gas pipe laying work can be performed safely and easily from the interior of the soil retaining unit to the construction surface. In particular, the support legs are projected from the soil retaining unit toward the construction surface, and the reaction force is obtained from the excavation surface on the construction surface side to support the soil retaining unit. Even if it exists, it is possible to prevent the earth retaining unit from falling over or sliding.

  As described above, according to the present invention, the construction space adjacent to the excavation groove while excavating the work excavation groove from the ground surface, such as when laying pipes such as gas pipes and water and sewage pipes in the ground, etc. When carrying out the prescribed construction work, the support legs can obtain reaction force from the excavation surface on the construction surface side, preventing the earth retaining unit from overturning or sliding, and more reliably Collapse can be prevented and safe civil engineering work can be realized.

It is a perspective view which shows the external appearance of the earth retaining unit which concerns on embodiment. It is a perspective view which shows the state which the earth retaining unit which concerns on embodiment decomposed | disassembled. It is a side view which shows the support leg of the earth retaining unit which concerns on embodiment. It is a perspective view which shows only the support leg of the earth retaining unit which concerns on embodiment. It is explanatory drawing which shows typically the procedure of the cutting method which concerns on embodiment. It is a sectional side view which shows the procedure of the cut-opening method concerning embodiment. It is a top view which shows the outline | summary of the branch taking-out work of the branch pipe performed by a general excavation work.

  Hereinafter, embodiments of the earth retaining method according to the present invention will be described in detail with reference to the accompanying drawings. In the present embodiment, the earth retaining unit of the present invention is described as an example applied to a construction for branching out a branch pipe from a main pipe that has been buried in advance, but the present invention is not limited to this. Applicable to all open-cut work such as pipes such as gas pipes, oil pipes, water and sewer pipes, power cables, telephone lines, protective pipes for optical fiber cables for communication, etc. Is possible.

(Composition of the soil retaining unit)
FIG. 1 is a perspective view showing an appearance of a soil retaining unit 1 used in the soil retaining method according to the present embodiment, and FIG. 2 is a perspective view showing an exploded state of the soil retaining unit.

  The earth retaining unit 1 is a temporary structure for earth retaining which is set in the excavation groove excavated by the excavation method and prevents the excavation surface of the excavation groove from collapsing. By stacking the unit units 11, 12 and 13, It can correspond to the depth of the excavation groove. Specifically, the earth retaining unit 1 is constructed by stacking three unit units 11, 12, and 13 of an upper part, a middle part, and a lower part in a vertical direction. In the present embodiment, the height of the lower unit 13 is set higher than the heights of the other upper unit 11 and the middle unit 12 to stabilize the lower part.

  Each unit unit has a retaining wall 112a, 112b, 122a, 122b, 132a, 132b, covers three surfaces of the excavation wall surface of the excavation groove 3 except the surface facing the construction space 34, and is adjacent to the construction space 34. Has an open surface (construction surface 10) for performing construction work, and a horizontal section is formed in a U-shape. Spacers 116, 126, and 136 are provided on the construction surface 10 so as to be spanned between the retaining walls 112b, 122b, and 132b arranged to face each other, and support earth pressure from both sides.

  Each of the unit units 11 to 13 has post portions 113a, 113b, 123a, 123b, 133a, and 133b that are column members connected in the vertical direction, and the earth retaining walls 112a and 112b are interposed between these post portions. , 122a, 122b, 132a, 132b are arranged. The retaining walls 112a to 132b are plate members made of steel, and fitting portions 114a and 114b that are fitted into the post portions of the unit units placed on the upper ends of the post portions 113a to 133b, 124a, 124b, 134a, 134b are attached.

  In addition, the pressure hood 111 which is a horizontal board member is attached to the upper surface part in 114a, 114b located in the uppermost part among these fitting parts. The pressure hood 111 is firmly fixed to the upper ends of the fitting portions 114a and 114b, and the unit unit can be settled by pressing the pressure hood 111 downward with a heavy machine or the like. Further, cutting shoes 135a and 135b to be embedded in the ground are attached to the lower ends of the post portions 133a and 133b of the lower unit 13 positioned at the lowermost layer.

  Furthermore, a pair of support legs 2 and 2 projecting toward the construction surface 10 are provided at the lower part of the soil retaining unit 1, and the reaction force from the excavation surface 32a on the construction surface 10 side by these support legs 2 and 2 is provided. And supporting the soil retaining unit 1 to suppress the fall and sliding. 3 and 4 show the support legs 2 and 2 in an enlarged manner.

  These support legs 2 and 2 are support structures that are respectively attached to the post portions 133b and 133b of the lower unit 13, and a leg portion 22 that is rotatably attached to the lower end of the post portion 133b, and a fixed end side of the leg portion 22 And the post part 133b are connected and stretched to roughly support the earth retaining unit 1 and a pile 23 held on the distal end side of the leg part 22.

  Further, a flange 136b having an insertion hole protrudes below the post portion 133b, and an engagement portion 22b having an insertion hole is formed on the rear end side of the leg portion 22, and these flanges are formed. With the insertion holes of 136b and the engaging portion 22b being aligned, the cylindrical pin 137b is inserted so that the flange 136b and the engaging portion 22b are pivotally engaged, and the leg portion 22 is the post portion. It is rotatably connected to 133b. On the other hand, a flange 136a having an insertion hole protrudes above the post portion 133b, and an engagement portion 21a having an insertion hole is formed on the rear end side of the support arm 21, and is engaged with the flange 136a. By inserting the cylindrical pin 137a in a state where the insertion holes of the joint portion 21a are aligned, the flange 136a and the engaging portion 21b are rotatably engaged, and the support arm 21 is attached to the post portion 133b. And are pivotally connected.

  On the other hand, a plurality of insertion holes 22 c are arranged along the longitudinal direction of the leg portion 22, and an engagement portion 21 a having an insertion hole is formed on the distal end side of the support arm 21. The support arm 21 is connected to the leg portion 22 by inserting the cylindrical pin 21c in a state in which the insertion hole 22c is selected and the insertion hole of the support arm 21 side engagement portion 21a is aligned therewith. . At this time, the attachment angle of the leg portion 22 is changed by appropriately selecting the insertion hole 22c. Further, a cylindrical cylindrical portion 22 a is fixed to the distal end portion of the leg portion 22, and the pile 23 is fixed to the distal end of the leg portion 22 by inserting the pile 23 into the cylindrical portion 22 a.

(Procedure of earth retaining method)
The earth retaining method using the earth retaining unit 1 having such a configuration is as follows. FIG. 5 is an explanatory view schematically showing a procedure of the earth retaining method in the open-cut method according to the present embodiment, and FIG. 6 is a side sectional view thereof. FIG. 7 is a top view showing an outline of the branch pipe branching work performed in the excavation work.

  The earth retaining method according to the present embodiment is implemented in an excavation method in which a predetermined construction work is performed on the construction space 34 adjacent to the excavation groove 3 while excavating the excavation groove 3 from the ground surface. More specifically, here, as shown in FIGS. 6 and 7, in order to perform construction for connecting the branch pipe 35 a to the main pipe 33 laid in advance, the excavation groove 34 is performed. 3 is excavated. The excavation groove 3 is sequentially excavated from the periphery of the branch extraction portion on the main pipe 33 over the installation range (construction space 34) of the branch pipe 35a. The main pipe 33 is disposed on the foundation concrete 33b, and the outer periphery of the main pipe 33 is protected by a part or all of the concrete 33a in some cases (in the illustrated example, a 180 ° portion of the outer periphery). Is protected.) For this reason, in the range where the main pipe 33 is laid, it is not possible to drive in a retaining material such as a sheet pile, or even if it is driven, sufficient depth and reaction force are obtained in the ground around the main pipe 33. Therefore, it is difficult to use the conventional earth retaining method.

  In the earth retaining method according to the present embodiment, first, the excavation groove 3 is excavated from the ground surface 30 by a heavy machine 4 such as a backhoe. This excavation groove 3 is an excavation groove for work, and is formed by a work groove 31 located on the main pipe 33 and an excavation groove 32 extending from the work groove 31 to the underground construction space 34, and this embodiment. Then, the operation of burying the branch pipe 35a in the excavation surface 32a of the cut groove 32 through the work surface 10 facing the work space 34 from the work groove 31 is performed. In the example shown in FIGS. 5 and 6, the main pipe 33 is already buried in the ground, and the working groove 31 is excavated above the main pipe 33 and also in the construction space 34. The existing pipe 35 b is buried, and the branch pipe 35 a is buried so as to pass below the existing pipe 35 b and connected to the main pipe 33.

  And with progress of excavation of the excavation groove 3, the unit units 11-13 of the earth retaining unit 1 are sequentially sunk. Specifically, the lower unit 13 is set in the working groove 31 at the initial stage of excavation, and as the excavation depth becomes deeper, the lower unit 13 is pushed downward by the heavy equipment 4 to be settled, and the next middle part is placed on the upper part. The unit 12 is placed and further pushed down by the heavy machine 4 to be settled. Similarly, the earth retaining wall which covers three surfaces except the construction surface 10 among the excavation wall surfaces of the work groove 31 is constructed by placing and sinking the upper unit 11. The built retaining wall is placed on the concrete 33a around the main pipe 33.

  At this time, in a predetermined stage of excavation, the support legs 2 and 2 are projected from the soil retaining unit 1 in the direction of the construction surface, and a reaction force is obtained from the excavation surface 32a on the construction surface 10 side to support the soil retaining unit 1. Specifically, the leg portions 22 are projected from the post portions 133b and 133b located on both sides of the construction surface 10 and pressed on the excavation surface 32a, and the reaction force is taken from the leg portion 22 by the support arm 21, The earth retaining unit 1 is supported in a direction opposite to the excavation surface 32a.

  Specifically, in a state where the insertion holes of the flange 136b and the leg-side engaging portion 22b are aligned on the lower side of the post portion 133b, the cylindrical pin 137b is inserted, and the leg portion 22 is inserted into the post portion 133b. And can be pivoted. On the other hand, on the upper side of the post portion 133b, with the insertion holes of the flange 136a and the support arm side engagement portion 21a being aligned, the cylindrical pin 137a is inserted to rotate the support arm 21 with respect to the post portion 133b. Connect movably. At the same time, after selecting the insertion hole 22c of the leg portion 22 and determining the mounting angle of the leg portion 22, the insertion hole of the engaging portion 21a on the support arm 21 side is aligned with the selected insertion hole 22. Then, the cylindrical pin 21 c is inserted, and the support arm 21 is connected to the leg portion 22.

  In addition, the said predetermined stage which provides the support legs 2 and 2 can be suitably selected according to the earth pressure P around the work groove 31, and the state of the excavation surface 32a, for example, all the unit units 11-13. It may be after sunk or immediately after the lower unit 13 is sunk. Moreover, as a timing which attaches the support legs 2 and 2 to the earth retaining unit 1, it may be attached to the lower unit in advance before the lower unit 13 is set, or may be attached after being set. Note that the mounting angles of the support legs 2 and 2 are also appropriately changed according to the earth pressure around the work groove 31 and the state of the excavation surface 32a as the excavation progresses. The spacers 116, 126, and 136 are attached at an appropriate timing according to the progress of the excavation and the earth pressure around the work groove 31. The spacers 116, 126, and 136 may obstruct the excavation work by the heavy machinery 4 or the burial work of the branch pipe 35 a, and can be omitted or removed as appropriate according to circumstances. Are also changed as appropriate.

  Next, at the distal end portion of the leg portion 22, the pile 23 is inserted into the cylindrical portion 22a, and the leg portion 22 is fixed to the excavation surface 32a by driving the pile 23 into the excavation surface 32a. Thereafter, the earth retaining unit 1 performs the construction work of burying the branch pipe 35a in the construction space 34 in the excavation groove 3 while supporting the earth pressure P from the three surrounding surfaces. Here, at the bottom of the working groove 31, the concrete pipe 33a is exposed over the concrete 33a, and the branch pipe 35a is branched and connected.

  And after this construction work is completed, the earth retaining unit 1 is removed and the excavation groove 3 is backfilled. The removal of the soil retaining unit 1 is performed, for example, by tying a wire to the unit unit and sequentially lifting it from the upper unit unit by a heavy machine according to the situation at the site.

(Action / Effect)
According to the present embodiment, the earth retaining unit 1 supports the earth pressure P from the three excavation surfaces excluding the construction surface 10 in the work groove 31 among the wall surfaces of the excavation groove 3. It is possible to prevent and ensure the safety of the work in the excavation groove. At this time, since the construction surface 10 side of the soil retaining unit 1 is open, it is possible to safely and easily perform operations such as the embedding work of the branch pipe 35a from the soil retaining unit to the excavation surface 32a. In particular, since the support legs 2 and 2 protrude from the soil retaining unit 1 toward the construction surface 10 and the reaction force is obtained from the excavation surface 32a on the construction surface 10 side, the soil retaining unit 1 is supported. Even when P acts, the earth retaining unit 1 can be prevented from falling or sliding.

(Example of change)
In addition, in the said embodiment, although the earth retaining unit 1 was comprised by three unit units 11-13 of upper, middle, and lower, this invention is not limited to this, According to the depth of a cut groove, a unit The depth of the soil retaining unit 1 can be pasted by appropriately changing the number of units.

  Further, in the above embodiment, the leg portion 22 is provided at the lower portion of the lower unit 13 and the support arm 21 is also attached to the upper portion of the lower unit 13, but depending on the ground condition to be cut and the depth of the cut groove, It may be attached to the unit unit. Furthermore, the mounting position of the support arm 21 may be the upper unit unit (for example, the middle unit 12), and the leg portion 22 attached to the lower unit 13 may be connected from the upper unit unit. In this case, the support arm 21 is replaced with a long one so as to correspond to the height between the plurality of unit units.

P ... earth pressure 1 ... earth retaining unit 2, 2 ... support leg 3 ... excavation groove 4 ... heavy machinery 10 ... construction surface 11 ... unit unit (upper unit)
12 ... Unit unit (central unit)
13 ... Unit unit (lower unit)
DESCRIPTION OF SYMBOLS 21 ... Support arm 21a, 21b ... Support arm side engaging part 21c, 137a, 137b ... Pin 22 ... Leg part 22a ... Cylindrical part 22b ... Leg part side engaging part 22c ... Insertion hole 23 ... Pile 30 ... Ground surface 31 ... Work Groove 32 ... Cleaving groove 32a ... Excavation surface 33 ... Main pipe 33a ... Concrete 33b ... Concrete concrete 34 ... Construction space 35a ... Branch pipe 35b ... Existing pipe 111 ... Pressure hood 112a, 112b, 122a, 122b, 132a, 132b ... During wall 113a , 113b, 123a, 123b, 133a, 133b ... post part 114a, 114b, 124a, 124b, 134a, 134b ... fitting part 116, 126, 136 ... spacer 135a, 135b ... cutting shoe 136a, 136b ... flange

Claims (2)

While excavating a work excavation groove from the ground surface, a earth retaining method when performing a predetermined construction work on the construction space adjacent to the excavation groove,
A step of sinking a soil retaining unit having a retaining wall covering three surfaces excluding a construction surface facing the construction space in the excavation groove in the excavation groove as the excavation progresses;
A step of projecting a support leg from the soil retaining unit toward the construction surface direction, obtaining a reaction force from the excavation surface on the construction surface side, and supporting the soil retaining unit;
And a step of performing the construction work on the construction space from within the excavation groove while supporting the earth pressure from the three surfaces by the earth retaining unit. A earth retaining unit used in the earth retaining method when performing predetermined construction work on a construction space adjacent to the excavation groove while excavating the excavation groove for work from the ground surface,
Of the excavation wall surface of the excavation groove, a horizontal wall covering the three surfaces excluding the construction surface facing the construction space, a U-shaped retaining wall,
A soil retaining unit, comprising: a support leg that protrudes from the retaining wall toward the construction surface, obtains a reaction force from the excavation surface on the construction surface side, and supports the retaining wall.