JP2013241756A - Construction method of underground structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a construction method of an underground structure with which the underground structure can be constructed in a short term even without being excavated.SOLUTION: It is desirable to construct a ground improvement 5 by continuously forming a ground solidification body using an injection system device. Steel pipes are installed within a range from a shaft 3a or 3b to the other shaft. Therefore, a pipe roof 7 is constructed to surround the outer periphery of the ground improvement 5 and at a side of the shafts 3a, 3b, both ends of the pipe roof 7 are exposed. Inside of the pipe roof 7 exposed within the shafts 3a, 3b, a steel support member 9 is disposed that is a first support section. Namely, both the end portions of the pipe roof 7 are supported by the steel support member 9. Furthermore, the vicinity of a central part of the pipe roof 7 is supported by the ground improvement 5.

Description

  The present invention relates to a method for constructing an underground structure capable of constructing an underground structure over a long distance with minimal influence on the ground.

  Conventionally, there is a method using a pipe roof as a method for constructing an underground structure. As such a pipe roof construction method, for example, a method of forming an outer shell that surrounds an area in which a horizontal shaft is to be excavated, excavating the inside of the outer shell to a predetermined extension, and then assembling a retaining support and constructing a horizontal shaft (Patent Document 1).

JP 2001-59393 A

  The conventional method as described in Patent Document 1 is to construct a temporary support inside the pipe roof while excavating the area surrounded by the pipe roof after constructing the pipe roof. This is because the earth pressure from the outer periphery is received by excavating the inside of the pipe roof.

  However, the method of excavating while constructing such a temporary support work requires man-hours for installation and removal of the temporary support work until the frame construction. In particular, when a pipe roof is constructed in a long range, there is a risk of ground surface displacement and the like due to temporary excavation and deformation or settlement of the pipe roof as well as excavation. Therefore, it is necessary to provide temporary support work with a pinch pitch. For this reason, the installation and removal man-hour of a temporary support work will be required further.

  Further, a part of the temporary support work is embedded with a column or the like when the housing is formed. Therefore, in order to construct a desired housing, it is necessary to construct a pipe roof in consideration of the installation space for the temporary support work. Therefore, a large pipe roof is required for the housing.

  However, if the construction range of the underground structure is performed by the open-cut method, it is necessary to stop the passage of vehicles, etc. on the upper road during the construction period for a long time. Therefore, there is a demand for a method for reliably building a long-range underground structure in a short period of time, even if it is not excavated.

  This invention is made | formed in view of such a problem, and it aims at providing the construction method of an underground structure which can construct | assemble an underground structure in a short time, even if it is non-open cutting.

  In order to achieve the above-mentioned object, the present invention is a method for constructing an underground structure, comprising a step a for constructing a pipe roof composed of a plurality of steel pipes supported at least near both ends by a first support portion, and the pipe An underground structure construction method comprising: a step b for excavating a space surrounded by a roof; and a step c for constructing a frame in the excavated space.

  Prior to the step a, the method further comprises a step d of improving the ground from the ground at least at one place to form a second support portion, and surrounding the second support portion in the step a. It is desirable to construct the pipe roof.

  The second support part is preferably constructed by continuously forming a ground solidified body by an injection system device.

  In the step a, the steel pipe may be placed so as to be in contact with a part of the outer peripheral portion of the second support portion. In the step a, the steel pipe is placed at a position away from the outer peripheral portion of the second support portion, and after the steel pipe is placed, from the inside of the steel pipe, between the steel pipe and the second support portion. You may improve the ground.

  The first support portion may be a steel support member, and in the step a, the steel support member may be disposed inside the pipe roof after the pipe roof is constructed.

  The first support part is constructed by ground improvement, and the step a improves the ground from the ground to form the first support part, and then surrounds the pipe roof so as to surround the first support part. You may cast it.

  After the step a, a core material may be disposed inside the steel pipe and filled with a solidified material.

  According to the present invention, since both ends of the pipe roof are previously supported by the support portion, when excavating the space surrounded by the pipe roof, it is necessary to install temporary supporters with a short pitch as in the prior art. Absent. That is, if the support pitch at both ends of the pipe roof is appropriate, temporary support work is not necessary. Therefore, it is not necessary to install and remove temporary support works.

  In addition, if the ground support is improved in advance from the ground before the pipe roof is constructed and the second support portion is formed, the support pitch of the pipe roof can be secured even for a longer underground structure. Therefore, even if the pipe roof is longer, there is no need to install a temporary support during excavation inside the pipe roof.

  In addition, since the second support portion is constructed by the injection system device, the effect of solidifying the ground is large, and the second support portion can be configured in a short time at a desired position.

  Moreover, the pipe roof can be reliably supported by the second support portion by placing the steel pipe so as to be in contact with the second support portion.

  Moreover, it is easy to place the steel pipe by placing the steel pipe at a position away from the second support portion and then improving the ground between the steel pipe and the second support portion. In addition, the pipe roof can be reliably supported by the second support portion.

  Moreover, if the 1st support part is a steel support member, a steel support member can be easily constructed | assembled in the edge part of the pipe roof exposed inside a shaft, etc., for example.

  Moreover, a 1st support part and a 2nd support part can be constructed | assembled by the same method by constructing | assembling a 1st support part by ground improvement.

  Further, by filling the steel pipe after placement with a core material and a solidifying material, the rigidity of the pipe roof can be increased, and deformation and the like can be prevented.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is non-open cutting, the construction method of the underground structure which can construct | assemble an underground structure in a short time can be provided.

It is a figure which shows the construction | assembly process of an underground structure, (a) is a top view, (b) is the sectional view on the AA line of (a). It is a figure which shows the shape of the ground improvement 5, and is the BB sectional drawing of FIG.1 (b). The top view which shows the construction process of an underground structure. (A) is the CC sectional view taken on the line of FIG. 3, (b) is the DD sectional view taken on the line of FIG. It is a figure which shows the construction process of an underground structure, (a) is a top view, (b) is the EE sectional view taken on the line of (a). It is a figure which shows the shape of the concrete frame 11, and is the FF sectional view taken on the line of FIG.5 (b). Sectional drawing which shows the structure of an underground structure. The figure which shows the state which constructed | assembled the ground improvement 5a, 5b. The figure which shows the construction form of the pipe roof 7. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig.1 (a) is a top view of the construction site of an underground structure, FIG.1 (b) is the sectional view on the AA line of Fig.1 (a). An underground structure is an underpass constructed at the intersection of roads 1a and 1b, for example. The underground structure of the present invention is not limited to the illustrated example.

  First, shafts 3a and 3b are constructed at predetermined positions on the road 1b across the road 1a. In order not to block the whole road 1b, first, a part of the road 1b is excavated, the upper part of the excavation part is closed with a top plate, the excavation range is expanded, and the shafts 3a and 3b having desired sizes are constructed. To do. By doing in this way, it is not necessary to stop the traffic of the vehicle with respect to the road 1b completely.

  The ground improvement 5 which is a 2nd support part is given to the both sides of the road 1a. The ground improvement 5 is desirably constructed by continuously forming a ground solidified body by an injection system device. By doing in this way, a solid ground improvement can be constructed in a short time. Moreover, since the apparatus is small, it is excellent in workability. Therefore, construction can be performed sequentially for each predetermined range without blocking the entire road 1b. In addition, with respect to the road 1a, the construction of the shafts 3a and 3b and the ground improvement 5 does not hinder the passage of vehicles.

  As shown in FIG.1 (b), the ground improvement 5 is constructed | assembled to the depth substantially equivalent to the shafts 3a and 3b. FIG. 2 is a cross-sectional view taken along line BB in FIG. The ground improvement 5 may be constructed for the entire predetermined range as shown in FIG. 2 (a), or a substantially rectangular hollow portion may be constructed as shown in FIG. 2 (b). As shown in FIG. 2C, a hollow portion with an arch shape may be constructed inside and below. In addition, the external shape of the ground improvement 5 respond | corresponds to the pipe roof shape mentioned later.

  Next, as shown in FIG. 3, a pipe pipe 7 is constructed by placing a steel pipe in a range from the shaft 3 a or the shaft 3 b to the other shaft. 4A is a sectional view taken along the line DD in FIG. 3, and FIG. 4B is a sectional view taken along the line CC in FIG. As shown in FIG. 4A, in the ground improvement 5, each steel pipe is constructed so that a part of the ground improvement 5 is cut and in contact with the ground improvement 5. In this case, since the ground is solidified compared with the non-improved portion, the ground improvement 5 may bend in the traveling direction when the steel pipe is placed.

  On the other hand, in the present invention, when the tip of the steel pipe reaches the position of the ground improvement 5, the steel pipe casting speed is reduced as compared with the time of placing on the non-improved portion, and the posture control is finer at the tip of the steel pipe. While doing, the steel pipe is driven straight. As described above, the pipe roof 7 is constructed so as to surround the outer periphery of the ground improvement 5.

  Moreover, as shown in FIG.4 (b), the both ends of the pipe roof 7 are exposed to the shafts 3a and 3b side. Inside the pipe roof 7 exposed in the shafts 3a and 3b, a steel support member 9 as a first support portion is arranged. Therefore, both ends of the pipe roof 7 are supported by the steel support members 9. That is, the vicinity of the center portion of the pipe roof 7 is supported by the ground improvement 5 and both ends are supported by the steel support members 9. Therefore, the pipe roof 7 is supported at a predetermined interval in the longitudinal direction.

  Fig.5 (a) is a top view which shows the state which excavated the pipe roof 7 inside from the shaft 3a, 3b to the ground improvement 5 vicinity, FIG.5 (b) is the EE line | wire of Fig.5 (a). It is sectional drawing. As shown in FIG. 5, after constructing the pipe roof 7, the inside of the pipe roof 7 is excavated from the shafts 3a and 3b, and the concrete frame 11 is placed therein. In addition, since the pipe roof 7 is supported at a predetermined interval in the longitudinal direction, it is not necessary to repeat the excavation and provisional support work in detail. That is, concrete can be placed while excavating at once from the end of the pipe roof 7 to the vicinity of the ground improvement 5.

  FIG. 6 is an example showing the concrete housing 11, and is a cross-sectional view taken along line FF in FIG. 5 (b). As described above, since the pipe roof 7 is supported by the both ends and the ground improvement 5, the pipe roof 7 in the range can be excavated at a time. Therefore, it is not necessary to install a temporary support work. For this reason, the concrete frame 11 can be constructed by excavating to the very inner surface of the pipe roof 7.

  In addition, when the concrete frame 11 is driven from both ends of the pipe roof 7, the concrete frame 11 can support the pipe roof 7 from the inside in this range. Therefore, as shown in FIG. 7, it is possible to further excavate between the ground improvements 5. Therefore, the concrete frame 11 can be constructed over the entire length in the pipe roof 7.

  As described above, according to the present embodiment, the inside of the pipe roof 7 is excavated in a state where both ends of the pipe roof 7 are supported. For this reason, the installation work of a temporary support work becomes unnecessary and an underground structure can be constructed in a short time.

  In particular, the ground improvement 5 is constructed in advance from the ground by an injection system device or the like, and the pipe roof 7 is constructed so as to come into contact therewith, so that the pipe roof 7 is grounded at predetermined intervals from the inside over a long distance. Can be supported by. Therefore, by constructing the ground improvement 5 at a predetermined interval, the pipe roof 7 can be reliably supported, and the excavation inside and the construction work of the concrete frame 11 can be facilitated. Moreover, since the work from the ground is only ground improvement, an underground structure can be constructed in a short period of time without excavation.

  In particular, if the installation length of the ground improvement 5 (length with respect to the longitudinal direction of the pipe roof 7) is increased, the support length of the pipe roof 7 by the ground improvement 5 can be increased. Therefore, the pipe roof 7 can be reliably supported.

  Moreover, after excavating the range supported by the ground improvement 5 from the position supported by the steel support member 9 and constructing the concrete frame 11 inside, excavating between the ground improvement 5 and the concrete frame 11 is built. For this reason, when excavating the ground improvement 5, both sides thereof are supported by the concrete frame 11. Therefore, the concrete frame 11 can be constructed by excavating at a time between the ground improvements 5.

  Further, since the temporary support work is not installed, it is not necessary to embed the temporary support work in the concrete frame 11. That is, the concrete frame 11 can be constructed up to the inner surface of the pipe roof 7. Therefore, it is not necessary to excessively increase the size of the pipe roof 7 for constructing the concrete casing 11 having a necessary size.

  Further, by constructing the ground improvement 5 only in the minimum necessary range and constructing a hollow portion inside in the cross section, excavation work in the pipe roof 7 becomes easy.

  As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

  For example, although the example which uses the steel support member 9 showed the support of the both ends of the pipe roof 7, this invention is not limited to this. For example, as shown in FIG. 8, the ground improvement 5a may be provided so as to face the shafts 3a and 3b, and further, the ground improvement 5b may be constructed so as to be separated from the ground improvement 5a. That is, both the first support portion and the second support portion may be performed by ground improvement. In this case, the pipe roof 7 is driven after constructing the first support portion and the second support portion.

  Moreover, according to the installation length of the pipe roof 7, the installation position and installation number of the ground improvement 5 which is a 2nd support part can be set suitably. If the entire length of the pipe roof 7 can be supported only by the first support portion, the ground improvement 5 may not be necessary.

  Moreover, although the example which construct | assembles the pipe roof 7 so that a part of the ground improvement 5 may be shaved when placing a steel pipe with respect to the ground improvement 5 was shown, this invention is not limited to this. For example, after constructing the pipe roof 7 at a position away from the outer periphery of the ground improvement 5 so as not to contact the ground improvement 5, an operator enters the steel pipe, and from the inside of the steel pipe, the outer peripheral surface of the ground improvement 5 and the steel pipe You may improve the unimproved ground between. If it does in this way, since the ground improvement 5 is not scraped off at the time of steel pipe placement, a steel pipe can always be cast in an unreformed part. Therefore, the work of placing the steel pipe is facilitated.

  Moreover, the steel pipe which comprises the pipe roof 7 may arrange | position core materials, such as a steel frame inside, and may be further filled with solidification materials, such as mortar, after casting. By doing in this way, the rigidity of steel pipe itself can be raised. Therefore, deformation of the pipe roof 7 can be prevented. For this reason, the installation interval of the ground improvement 5 can be expanded, or the ground improvement range can be narrowed.

  Moreover, the pipe roof 7 does not necessarily need to be a rectangle, and does not need to have a shape in which the entire circumference is completely closed. For example, when there is a clayey ground 13 or the like in the lower part, the ground improvement 5c may be constructed in a U-shape opening downward as shown in FIG. 9 instead of a rectangle. In this case, a U-shaped pipe roof 7a corresponding to the ground improvement 5c may be constructed.

  Moreover, the pipe roof 7 does not necessarily need to be constructed from the shafts 3a and 3b. For example, when constructing an underground structure with respect to the embankment, pipe roofs may be constructed from both sides of the embankment. Even in this case, the ground may be improved on the embankment or on the side of the embankment.

1a, 1b ......... Roads 3a, 3b ......... Vertical shafts 5, 5a, 5b, 5c ......... Ground improvement 7, 7a ......... Pipe roof 9 ......... Steel support member 11 ......... Concrete frame 13 ... …… Clayy ground

Claims (8)

A construction method of an underground structure,
A step a in which at least the vicinity of both ends is supported by the first support portion and a pipe roof composed of a plurality of steel pipes is constructed;
A step b of excavating the space surrounded by the pipe roof;
Constructing a housing in the excavated space; c.
The construction method of an underground structure characterized by comprising. Before the step a, further comprising the step d of improving the ground from the ground in at least one place to form a second support part,
The method for constructing an underground structure according to claim 1, wherein in the step a, the pipe roof is constructed so as to surround the second support portion.   The construction method for an underground structure according to claim 2, wherein the second support part is constructed by continuously forming a ground solidified body by an injection system device.   4. The method for constructing an underground structure according to claim 2 or 3, wherein the step a places the steel pipe so as to be in contact with a part of an outer peripheral portion of the second support portion.   In the step a, the steel pipe is placed at a position away from the outer peripheral portion of the second support portion, and after the steel pipe is placed, from the inside of the steel pipe, between the steel pipe and the second support portion. The construction method for an underground structure according to claim 2 or 3, wherein the ground improvement is performed. The first support part is a steel support member,
6. The construction of an underground structure according to claim 1, wherein, in the step a, the steel support member is disposed inside the pipe roof after the pipe roof is constructed. Method. The first support portion is constructed by ground improvement,
The step a is characterized in that after the ground is improved from the ground to form the first support portion, the pipe roof is driven so as to surround the first support portion. The construction method of the underground structure in any one of 5.   The method for constructing an underground structure according to any one of claims 1 to 7, wherein after the step a, a core material is arranged inside the steel pipe and a solidified material is filled.

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