JP2011202402A - Method of construction of underground structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of construction of an underground structure by which a curved part can be constructed and sinkage of a ground surface after precedent excavation can be suppressed.SOLUTION: The method is to construct the underground structure 1 extending from a start vertical shaft 51 to a horizontal ground G. The method includes steps of: propelling a steel box body 2 from the start vertical shaft toward the position of the ground where an upper part of the underground structure is formed; constructing earth retaining piles 31 from the inside of the steel box body to the position where a side face of the underground structure lower than the steel box body is formed; constructing a plurality of supporting piles 4 downward from the inside of the steel box body; constructing a ceiling structure 11 extending among head parts of the supporting piles; excavating under the ceiling structure along the earth retaining piles; and constructing the remaining parts of the underground structure in the excavated space under the ceiling structure.

Description

  The present invention relates to a method for constructing an underground structure used for a subway, an underground road, or a junction branching portion thereof in an urban area or a place where the ground is weak.

  Conventionally, when constructing an underground structure by excavating the ground, in order to suppress subsidence of the ground surface, a flat roof-like pipe roof is constructed by first pushing a plurality of steel pipes toward the ground. There is known a method of advancing excavation while supporting an inner ground protected by a roof by a supporting work (see Patent Document 1).

  Further, in Patent Document 2, a plurality of roof cylinders and a portal-shaped friction cut plate that collectively covers the outer periphery of the roof structure and a portion corresponding to the ceiling and the upper part of the side wall of the underground structure are advanced. A method is disclosed in which a rectangular underground structure is dug below a friction cut plate while sequentially removing cylinders.

  Furthermore, in Patent Document 3, a plurality of rectangular roofs and a portal cover plate covering them are dug ahead of the portion corresponding to the ceiling of the underground structure, and the rectangular roof is sequentially removed, and then the same size as the underground structure. The construction method of the underground structure performed by excavating this cross-section excavator is disclosed.

Japanese Patent No. 3511145 JP 2001-73670 A JP 2008-303681 A

  However, when a pipe roof in which the steel pipes are just adjacent to each other as in Patent Document 1 is constructed, since the mutual connection force is weak, the support work for receiving the pipe roof becomes large and hinders internal excavation. The construction cost was high. In addition, when adjacent pipe roofs are connected by a joint or the like, the binding force of the connecting portion becomes too strong, so that it is difficult to provide a curved portion, and only a straight underground passage can be constructed.

  On the other hand, in the methods of Patent Documents 2 and 3, since the roof cylinder and the rectangular roof to be excavated in advance are only supported by the ground, the lower ground is used to excavate the underground structure or the cross-section excavator. When excavating, the ground cover may loosen and the ground surface may sink.

  Therefore, an object of the present invention is to provide a method for constructing an underground structure capable of constructing a curved portion and suppressing the settlement of the ground surface after preceding excavation as much as possible.

  In order to achieve the above object, a method for constructing an underground structure according to the present invention is a method for constructing an underground structure that constructs an underground structure that extends from an underground space toward a ground in a lateral direction. Digging the box from the space toward the ground including the position where the upper part of the underground structure is formed, and toward the position where the side surface of the underground structure below the box is formed, It is spanned between the step of constructing at least a part of the earth retaining body from the inside of the box, the step of building a plurality of support piles downward from the inside of the box, and the heads of the plurality of support piles A step of constructing an upper structure inside the box, a step of excavating a lower part of the upper structure along the earth retaining body, and a remaining excavation space below the upper structure in the excavation space below the upper structure. And a process of constructing a part of .

  Further, the box extending from the underground space may have a plurality of rows so as to be arranged side by side in the width direction of the underground structure. Further, the plurality of rows may be provided at intervals in the width direction and may include a step of connecting the boxes. And the said support pile can be constructed | assembled from each of the said box.

  In the construction method of the underground structure of the present invention configured as described above, a box is first arranged at a position where the upper part of the underground structure is formed, and a plurality of support piles are arranged downward from the inside of the box. To construct. And after spanning an upper structure between the heads of those support piles, the lower structure of an upper structure is excavated and an underground structure is constructed.

  For this reason, the excavation after excavating the box is excavation below the upper structure supported by the support pile, so the ground above the upper structure is loosened and the ground surface hardly sinks. . In addition, since the box to be dug in advance can be dug in accordance with the alignment even if it is a curved part, the curved part of the tunnel can be easily constructed.

  Furthermore, if it is the method of arranging a plurality of boxes in parallel, the amount of excavation at one time is small, and the amount of settlement can be suppressed. Moreover, if it is the method of excavating a box at intervals in the width direction, even a curved part with a large curvature can be easily excavated. And if it is a method of constructing a support pile from each box, a load can be distributed. In addition, the settlement of the ground surface can be suppressed without making the upper structure highly rigid just for provisional receiving.

It is a cross-sectional view explaining the construction method of the underground structure of the embodiment of the present invention. It is a cross-sectional view explaining the process of excavating a box. It is a longitudinal cross-sectional view explaining the process of returning the excavator which excavated the box to the starting vertical shaft. It is a perspective view explaining the state which arranged the box in the width direction. It is a cross-sectional view explaining the process of constructing a support pile and an upper structure. It is a cross-sectional view explaining the process of completing an underground structure. It is a figure explaining the construction method of the underground structure of Example 1, Comprising: (a) is a figure explaining the process until it builds a support pile, (b) is a figure explaining the process of building an upper structure. It is. It is a figure explaining the construction method of the underground structure of Example 2, Comprising: (a) is a figure explaining the process of connecting between boxes, (b) explains the process of constructing a support pile and an upper structure. It is a figure to do. It is a figure explaining the construction method of the underground structure of Example 3, Comprising: (a) is a figure explaining the process until it builds a support pile, (b) is a figure explaining the process of building an upper structure. It is. It is a figure explaining the process of connecting between the boxes of Example 4.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1-6 is a figure explaining the construction method of the underground structure 1 of this Embodiment.

  The underground structure 1 is constructed in a relatively shallow part of the ground covering a ground G where a railroad or road is extended on the ground surface, for example, and is used for a subway, an underground road, or a junction branching portion thereof. A rectangular structure.

  In constructing the underground structure 1, as shown in FIG. 3, a start shaft 51 as an underground space and an arrival shaft 52 as an underground space are constructed. Then, the underground structure 1 is extended between the start shaft 51 and the reaching shaft 52. For this reason, the line connecting the starting shaft 51 and the reaching shaft 52 is the extending direction. Here, as shown in FIG. 4, the case where the underground structure 1 of a planar view arc shape with a curved part is constructed | assembled is demonstrated.

  In addition, the ground G above the constructed underground structure 1 is provided with a sewage box S1, a water pipe S2, a manhole S3, etc., as shown in FIG. It has become.

  Further, the steel box 2 as a box to be excavated from the starting vertical shaft 51 toward the reaching vertical shaft 52 is excavated by, for example, attaching an excavator 53 to the tip and pushing it out from the starting vertical shaft 51 by the propulsion jack 55.

  The excavator 53 mainly includes a cutter portion 53a having a cutter bit on the front surface, a trunk portion 53b connected to the rear thereof, and a roof portion 53c that protects the cutter portion 53a and the trunk portion 53b. The excavator 53 is manufactured so that the cutter part 53a, the body part 53b, and the roof part 53c can be easily disassembled and assembled.

  The start shaft 51 is provided with a reaction wall 54 for securing a reaction force of the propulsion jack 55, a pedestal 56 interposed between the propulsion jack 55 and the steel box 2, and the like.

  And the steel box 2 dug into the ground G by the excavator 53 and the propulsion jack 55 is formed in a short cylindrical shape having a rectangular front view as shown in FIGS. That is, FIG. 2 shows a state in which five steel boxes 2,... Are juxtaposed in the width direction orthogonal to the extending direction of the underground structure 1. On the other hand, FIG. 3 is the figure which looked at steel box 2, ... from the side. That is, as shown in FIG. 4, five rows of steel boxes 2,...

  These five rows of steel boxes 2,... Are arranged on the ground G where the upper part of the underground structure 1 is formed, as shown in FIG. Then, as shown in FIG. 5, the retaining piles 31, 31 and the support piles 4,... Are driven from the inside of the steel boxes 2,.

  This earth retaining pile 31 is a member which comprises a part of earth retaining wall 3 as a earth retaining body. That is, the retaining wall 3 is formed in a wall shape by a retaining plate or a sheet pile (not shown) spanned between the retaining piles 31 and 31 after excavation, with the retaining pile 31 placed in advance as a support.

  Moreover, this earth retaining pile 31 is driven in along the position where the side surface of the underground structure 1 is formed. That is, the earth retaining pile 31 is driven from the inside of the steel boxes 2, 2 at both ends of the steel boxes 2,.

  On the other hand, the support pile 4 is driven with an interval between the retaining piles 31, 31. For example, as shown in FIG. 5, support piles 4,... Are provided for each of five steel boxes 2,. Moreover, the support pile 4 ensures support force by driving in to the support layer G1. Furthermore, as shown in FIG. 4, the earth retaining piles 31,... And the support piles 4,.

  On the other hand, in the steel boxes 2,..., A ceiling structure 11 is constructed as an upper structure that forms the upper part of the underground structure 1. As shown in FIG. 5, the ceiling structure 11 is constructed by integrally forming a flat ceiling portion 111 and upper side walls 112, 112 suspended from both side edges thereof with reinforced concrete or the like. . Here, since the ceiling part 111 is constructed across a plurality of steel boxes 2,..., The steel shell of the steel box 2 that is a part of the ceiling part 111 is cut off. Will be removed.

  Further, a receiving portion 41 such as a hydraulic jack is interposed between the lower surface of the ceiling portion 111 and the upper end of the support pile 4. Thus, the ceiling structure 11 is bridged across the heads of the plurality of support piles 4.

  Next, the construction method of the underground structure 1 of the present embodiment will be described.

  First, as shown in FIG. 3, a start shaft 51 and a reach shaft 52 are respectively constructed at both ends of a section in which the underground structure 1 is constructed. In addition, a reaction wall 54, a propulsion jack 55, a gantry 56, and the like are installed inside the start shaft 51.

  Then, the excavator 53 and the steel box 2 are carried into the start shaft 51, and the steel box 2 is connected to the rear of the excavator 53. Further, a gantry 56 is disposed behind the steel box 2, and the tip of the propulsion jack 55 is brought into contact with the back surface of the gantry 56.

  Subsequently, the excavator 53 is started from the start port 51 a of the start shaft 51 toward the ground G. The ground G is cut by the cutter portion 53 a of the excavator 53, and the excavator 53 and the steel box 2 are pushed out to the ground G by the thrust of the propulsion jack 55.

  In addition, according to the progress of the excavation of the steel box 2, by adding a new steel box 2 between the steel box 2 at the rearmost part and the mount 56 inside the start shaft 51, The steel boxes 2,... Are extended until reaching the arrival port 52a of the arrival shaft 52.

  In this way, after the start shaft 51 and the arrival shaft 52 are connected by the first row of steel boxes 2,..., The excavator 53 is disassembled inside the arrival shaft 52, and the steel case 2 ... The excavator 53 disassembled to the start shaft 51 is returned using the tunnel formed by the group.

  Then, in the start shaft 51, the excavator 53 is assembled again, and the second row of steel boxes 2,... Is dug from the first row of steel boxes 2,. The order of the excavation may be performed every other row in the five rows, or may be performed close to each other.

  Thus, when the steel boxes 2,... Are dug in each row, as shown in FIG. 4, the five rows of steel boxes 2,. A tunnel group is constructed.

  Furthermore, after the tunnel of the steel boxes 2,... From the start shaft 51 to the arrival shaft 52 is opened, the steel boxes 2,. In parallel with the excavation work, the retaining pile 31 and the support pile 4 can be driven from the inside of the steel boxes 2,...

  In addition, before placing the retaining pile 31 and the support pile 4, the ground improvement may be performed by injecting a chemical solution or the like to the lower ground G from the inside of the steel box 2,. Reduce the groundwater level.

  Moreover, what is necessary is just to drive the earth retaining pile 31 to the depth which can ensure the yield strength required as the earth retaining wall 3 when excavating the ground G below the steel boxes 2,. On the other hand, the support pile 4 is driven up to the support layer G1 in order to support the ceiling structure 11 and its overload.

  On the other hand, the steel shell between the steel boxes 2 and 2 that hinders the construction of the ceiling structure 11 is cut and removed, and the adjacent steel boxes 2 and 2 are communicated with each other. And the ceiling-shaped part 111 straddling between steel boxes 2, ... and the upper side walls 112 and 112 of the both-sides edge are integrally shape | molded by reinforced concrete, and a portal-shaped ceiling structure as shown in FIG. 11 is built.

  Here, the support piles 4,... Can be used for the support work required for the construction of the ceiling structure 11. That is, it can be set as a support work by extending | stretching the hydraulic jack of the receiving part 41 and ..., and making it contact | abut to the lower surface of the formwork of the ceiling part 111.

  And as shown in FIG. 1, the ground G below the ceiling structure 11 supported by the support pile 4, ... is excavated. This excavation is performed on the ground between the retaining piles 31, 31, and the retaining wall 3 is constructed by attaching a retaining plate (not shown) to the retaining pile 31 exposed by the excavation. Moreover, between the earth retaining walls 3 and 3, the cut beam 32 and the erection 32a and 32a are installed.

  In this way, the excavation bottom G2 is dug down, and the lower structure 12 of the underground structure 1 is constructed of reinforced concrete as shown in FIG. 6 in the excavation space excavated to a predetermined depth. The lower structure 12 is formed in a groove shape by a bottom plate and lower side walls erected from both side edges thereof, and is joined to the lower ends of the upper side walls 112 and 112 of the ceiling structure 11 so as to be an integral underground structure. 1

  Then, the support piles 4,..., The receiving portions 41,... Remaining in the underground structure 1 are removed to complete the underground structure 1.

  Next, the effect | action of the construction method of the underground structure 1 of this Embodiment is demonstrated.

  In the construction method of the underground structure 1 of the present embodiment configured as described above, first, the steel boxes 2,... Are arranged at positions where the upper part of the underground structure 1 is formed, and the steel box A plurality of support piles 4,... Are constructed from the inside of the bodies 2,. And after spanning the ceiling structure 11 between the heads of those support piles 4..., The underground structure 1 is constructed by excavating the ground G below the ceiling structure 11.

  That is, excavation of the ground G after excavating the steel boxes 2,... Is performed below the ceiling structure 11 supported by the support piles 4,. For this reason, there is almost no possibility that the ground G above the ceiling structure 11 loosens and the ground surface sinks.

  Further, since the steel box 2,... To be dug in advance can be dug according to the alignment even if it is a curved portion, it can be easily constructed even in a curved portion of a tunnel. .

  Furthermore, if the method is to divide the area to be excavated and dig a small steel box 2, ..., the amount of excavation at one time is small, the stress released at once is also reduced, The amount of settlement can be suppressed.

  And if it is the method of constructing the support piles 4, ... from each of the plurality of adjacent steel boxes 2, ..., stress concentration is unlikely to occur because the load can be dispersed. Moreover, if the span between the support piles 4 and 4 is short, it is possible to sufficiently suppress the settlement of the ground surface without making the ceiling structure 11 highly rigid only for provisional reception.

  Next, a construction method of the underground structure 1 in a form different from the above embodiment will be described with reference to FIG. The description of the same or equivalent parts as those described in the above embodiment will be given the same reference numerals.

  In the first embodiment, as shown in FIG. 7A, a case where steel boxes 2 </ b> A as a box are arranged at intervals in the width direction of the underground structure 1 will be described. That is, in Example 1, the steel box 2A having a rectangular shape in front view is dug at a constant interval. Thus, if there is a space between the steel boxes 2A, 2A, it is possible to easily excavate even if the linear shape has a large curvature.

  And between steel box 2A, 2A is connected by a connection work. In the first embodiment, the connection is made by digging between the steel boxes 2A and 2A, the connection box 21 having a height about half that of the steel box 2A. For this reason, the amount of excavation by the excavator 53 can be reduced as compared with the above-described embodiment, leading to a reduction in work period and work cost.

  Further, a ceiling structure 11A is constructed of reinforced concrete between the steel box 2A,... And the connection boxes 21,. The ceiling structure 11A includes a ceiling portion 111A formed to have a thickness substantially the same as the height of the connection box 21, upper side walls 112A and 112A suspended from both side edges, and inner steel boxes 2A and 2A. Are mainly constituted by the ribs 113A and 113A provided inside.

  When the steel boxes 2A and 2A arranged at intervals in this way are connected by the connecting box 21 having the same height as the thickness of the ceiling portion 111A, the formwork on the lower surface side of the ceiling portion 111A is omitted. can do.

  Other configurations and operational effects are substantially the same as those of the above-described embodiment or other examples, and thus description thereof is omitted.

  Next, a construction method of the underground structure 1 in a form different from the above embodiment and Example 1 will be described with reference to FIG. The description of the same or equivalent parts as those described in the above embodiment or Example 1 will be given the same reference numerals.

  In the second embodiment, similarly to the first embodiment, the box is dug at intervals in the width direction of the underground structure 1. However, the box used in Example 2 is a cylindrical steel box 2B.

  Then, the steel box bodies 2B, 2B arranged at intervals as shown in FIG. 8A are connected using a curved pipe roof 22. That is, an arcuate roof is constructed by continuously arranging the curved pipe roofs 22 in the direction perpendicular to the plane of the paper, and the ground below is excavated to communicate between the steel boxes 2B and 2B.

  Moreover, the ceiling provided with the ceiling part 111B straddling between steel box 2B, ..., the upper side wall 112B, 112B suspended from the both-sides edge, and the rib 113B, 113B which protrudes from the lower surface of the ceiling part 111B The structure 11B is integrally constructed of reinforced concrete.

  If the steel boxes 2B,... Are dug in such a manner as described above, even the underground structure 1 having a curved portion with a large curvature can be easily constructed. In addition, if the ground condition is relatively good, the construction cost and the construction period can be reduced by applying a connection work that can be easily constructed, such as the curved pipe roof 22.

  Other configurations and operational effects are substantially the same as those of the above-described embodiment or other examples, and thus description thereof is omitted.

  Next, a construction method of the underground structure 1 in a form different from the above embodiment and Examples 1 and 2 will be described with reference to FIG. The description of the same or equivalent parts as those described in the embodiment or Examples 1 and 2 will be given with the same reference numerals.

  In the embodiment and Examples 1 and 2, the case where the steel boxes 2, 2A, 2B having small cross sections are arranged side by side has been described. In Example 3, as shown in FIG. The steel box 2C having a large cross section is dug, and the retaining piles 31, 31 and the plurality of support piles 4,.

  Such a steel box 2C can be arranged by a shield method or the like. That is, this steel box 2C is formed by combining a plurality of arc-shaped segments.

  Moreover, as shown in FIG.9 (b), 11C of ceiling structures are constructed | assembled along the internal peripheral surface of 2C of steel boxes. That is, the ceiling structure 11C includes a semicircular ceiling portion 111C, upper side walls 112C and 112C suspended from both side edges thereof, and an intermediate connecting the ceiling portion 111C and the heads of the support piles 4,. The walls 113C,... Are integrally formed of reinforced concrete. Moreover, in this Example 3, the earth retaining pile 31 and the upper side wall 112C are also connected.

  In this way, if it is a method of constructing a plurality of support piles 4,..., And earth retaining piles 31, 31 from the inside of one steel box 2C, the pile driver can be easily moved. The support pile 4 and the retaining pile 31 can be driven. Moreover, even if it does not cut | disconnect a steel shell, 11C of ceiling structures which straddle several support piles 4 ... can be constructed | assembled easily.

  Other configurations and operational effects are substantially the same as those of the above-described embodiment or other examples, and thus description thereof is omitted.

  Next, the construction method of the underground structure 1 in a form different from the above embodiment and Examples 1-3 will be described with reference to FIG. The description of the same or equivalent parts as those described in the embodiment or Example 1-3 will be given with the same reference numerals.

  In the fourth embodiment, the box is dug at intervals in the width direction of the underground structure 1 as in the first and second embodiments. And as shown in FIG. 10, the slide steel plates 23 and 23 are passed up and down between the steel boxes 2D and 2D arranged at intervals.

  This slide steel plate 23 is housed in the back of the ceiling and under the floor of one steel box 2D when the steel box 2D is being dug, and connects the steel boxes 2D and 2D in the width direction. In FIG. 10, the steel box 2D is passed from one steel box 2D to the other adjacent steel box 2D (in FIG. 10, from the left steel box 2D to the right steel box 2D).

  Further, a water stop portion 24 is constructed on the ground G outside the slide steel plate 23 by a chemical solution injection method or a freezing method. Then, the ground surrounded by the side walls of the steel boxes 2D and 2D and the upper and lower slide steel plates 23 and 23 is excavated to communicate the steel boxes 2D and 2D in the width direction.

  If the step of connecting the two steel boxes 2D and 2D is performed by passing the slide steel plates 23 and 23 in this way, there will be some construction error at the digging position of the steel boxes 2D and 2D. Even if there is, connection can be made easily.

  Other configurations and operational effects are substantially the same as those of the above-described embodiment or other examples, and thus description thereof is omitted.

  The embodiment of the present invention has been described in detail above with reference to the drawings. However, the specific configuration is not limited to the embodiment and the example, and the design change is within a range not departing from the gist of the present invention. Are included in the present invention.

  For example, in the said embodiment, although the starting shaft 51 was demonstrated as underground space, it is not limited to this, The tunnel connected to the underground structure 1 can also be made into underground space.

  Moreover, although the said embodiment demonstrated the case where the excavator 53 excavated from the start shaft 51 was decomposed | disassembled inside the arrival shaft 52 and returned to the start shaft 51, it is not limited to this, Excavator By making U-turn 53 in the inside of the vertical shaft 52 and making it excavate toward the start vertical shaft 51, the tunnel of the following steel boxes 2, ... can be constructed. Furthermore, when the excavator 53 reaches the start shaft 51, the excavator 53 may make a U-turn inside the start shaft 51 and advance toward the reach shaft 52.

  Moreover, although the said embodiment demonstrated the case where the retaining wall 3 which has the retaining pile 31 as a retaining body was constructed | assembled, it is not limited to this, A continuous underground wall is made from the inside of the steel box 2 It can also be constructed as a soil body.

  Furthermore, in the said embodiment and Example, although the case where the face-plate-like ceiling structures 11, 11A, 11B, and 11C were constructed | assembled first was demonstrated, it is not limited to this, A beam-like upper structure The ceiling part of the underground structure 1 that connects the beam-shaped upper structures later by supporting the ceiling of the steel box 2,. May be constructed.

  Moreover, in the said embodiment and Example, although the case where the underground structure 1 was constructed | assembled with a reinforced concrete was demonstrated, it is not limited to this, It constructs | assembles using steel reinforced concrete, prestressed concrete, precast concrete, etc. Also good.

  Furthermore, in the said embodiment, although one part of the underground structure 1 was constructed | assembled as the ceiling structure 11, it is not limited to this, The ceiling structure 11 is constructed | assembled as temporary construction, The ceiling structure 11 of A separate underground structure 1 may be provided below.

1 Underground structure 11, 11A, 11B, 11C Ceiling structure 12 Lower structure (the remaining part of the underground structure)
2,2A, 2B, 2C, 2D Steel box (box)
21 Connection box 22 Curved pipe roof 23 Slide steel plate 3 Earth retaining wall (earth retaining body)
31 Dust pile 4 Support pile 51 Starting shaft (underground space)
52 Reaching shaft (underground space)
G ground

Claims (4)

An underground structure construction method for constructing an underground structure extending from an underground space toward a lateral ground,
A step of excavating the box from the underground space toward the ground including the position where the upper part of the underground structure is formed;
To construct at least a part of the earth retaining body from the inside of the box toward the position where the side surface of the underground structure below the box is formed;
Building a plurality of support piles downward from the inside of the box;
Constructing an upper structure spanning between the heads of the plurality of support piles inside the box;
Excavating a lower part of the upper structure along the earth retaining body;
And a step of constructing a remaining portion of the underground structure in an excavation space below the upper structure.   The method for constructing an underground structure according to claim 1, wherein the box extending from the underground space is provided with a plurality of rows so as to be aligned in the width direction of the underground structure.   The method for constructing an underground structure according to claim 2, wherein the plurality of rows are provided at intervals in the width direction and include a step of connecting the boxes.   The construction method of an underground structure according to claim 2 or 3, wherein the support pile is constructed from each of the boxes.

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