JP2007332720A - Construction method for underground structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a construction method for an underground structure capable of constructing the underground structure comprised of a small-cross-section tunnel group even if a vertical shaft is not constructed. <P>SOLUTION: This is a method for constructing a widened part 100 by surrounding a natural ground 6 with a small-cross-section tunnel group 10 coupled with side surfaces of a plurality of small-cross-section tunnels 111,121,131 and 141 and by excavating the surrounded natural ground. After excavating with a shield machine 21 which is provided with a plurality of small-cross-section shield machine, the plurality of small-cross-section tunnels is constructed with intervals by excavating with the plurality of small-cross-section shield machines toward one of the end 100a of the both ends 100a and 100b in a longitudinal direction of the widened part 100 and similarly by excavating toward the other end 100b so that the small-cross-section tunnel group coupled with the side surfaces is formed by constructing a small-cross-section tunnel 131 between a small-cross-section tunnel 111 previously constructed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a construction method for constructing underground structures such as branching / merging sections of underground roads, subway station buildings, large-section tunnels, underground storage facilities, or underground parking lots.

  Conventionally, as disclosed in Patent Documents 1 to 3 and the like, as a method for constructing underground structures having a large cross section in the ground, the outer shell of the large cross section tunnel is surrounded by a plurality of small cross section tunnels. There is known a method of excavating the natural ground after forming the ground.

  In these methods, as a base for starting and reaching a shield excavator that constructs a small section tunnel, shafts with openings on the ground surface are constructed on the start side and the arrival side, and a small section tunnel group is formed between the shafts. Is building.

On the other hand, Patent Documents 4 and 5 disclose a parent-child type shield excavator including a plurality of small-section shield excavators.
Japanese Patent Publication No. 7-86320 Japanese Patent No. 3084500 JP 2000-310100 A JP 2001-254591 A Japanese Patent Laid-Open No. 10-176479

  However, the construction cost and construction period of this shaft will increase as the depth of the tunnel increases, and in the city center it will be difficult to acquire land for the site where the shaft will be constructed, and the start of construction will be delayed or the route will not be changed. There is a risk of problems such as being in a situation where it is difficult to manage.

  Therefore, an object of the present invention is to provide an underground structure construction method capable of constructing an underground structure composed of small-section tunnel groups without constructing a shaft.

  In order to achieve the above-mentioned object, the underground structure construction method of the present invention surrounds a natural ground by a small-section tunnel group in which side surfaces of a plurality of small-section tunnels are connected, and excavates the enclosed natural ground. In the construction method of the underground structure to be constructed, after digging a shield excavator equipped with a plurality of shield excavators having a small cross section, one end of the underground structure as both ends in the longitudinal direction Before reaching the end, the shield excavator is stopped, a plurality of small-section shield excavators are started toward the one end, and after passing through the one end, small until reaching the other end. A plurality of small cross-section tunnels that are spaced apart by excavating the cross-section shield excavator are constructed, and similarly, the other end portion is also provided with a plurality of small cross-section shield excavators from the side opposite to the shield excavator. Digging the shield excavator Before reaching the other end, the shield excavator is stopped and a plurality of small-section shield excavators are started between the small-section tunnels. It is characterized in that a tunnel is constructed to form a small-section tunnel group in which side surfaces are connected.

  Here, after the small-section tunnel is constructed, the cutting portion on the front surface of the small-section shield excavator is collected, and the collected cutting portion is arranged on the front surface of the shield excavator from which the small-section shield excavator is started. Then, the shield excavator can be advanced again.

  In the construction method of the underground structure of the present invention configured as described above, a shield excavator having a plurality of small-section shield excavators is dug to a predetermined depth, and these small-section shield excavators are underground. A plurality of small section tunnels constructed by starting are connected to construct a small section tunnel group.

  In this way, it is possible to build an underground structure that surrounds the natural ground by a small section tunnel group without constructing a shaft, so there are problems with the site, construction cost and increase in construction period that occur when constructing a shaft This problem does not limit the construction of underground structures.

  In addition, the cutting section of the small-section shield excavator used for the construction of the small-section tunnel group is collected, and the collected cutting section is returned to the shield excavator from which the small-section shield excavator was started, so that the shield excavation is performed again. You can dig up the machine.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a side view showing a schematic configuration of the widened portion 100 as an underground structure constructed by the underground structure construction method of the present embodiment.

  The widening portion 100 is constructed in the ground as, for example, a subway station building. Access tunnels 11 to 14 for accessing the widening portion 100 and a main tunnel 15 through which the subway runs are connected to both ends 100a and 100b of the widening portion 100. Connected.

  In the construction method of the underground structure of the present embodiment, a plurality of small cross-section shield excavators 211A to 211G as shown in FIG. )) Is used.

  The shield excavator 21 is provided with a small cross-section shield excavator 211G at the center, and a plurality of small cross-section shield excavators 211A to 211F are provided around the annular rocking portion 212.

  When this small-section shield excavator 211 is provided in the shield excavator 21, the small-section shield excavator 211 rotates independently and excavates the front ground 6 by the cutting unit 213. Moreover, the annular rocking | swiveling part 212 rock | fluctuates around the small-section shield excavator 211G of the center by the expansion-contraction of the hydraulic jack etc. which are not shown in figure at an angle of 30-45 degree | times, for example, and small-section shield excavator 211A-211F. The natural ground 6 in the gap is also cut.

  In the natural ground 6 excavated by the shield excavator 21, a lining material such as an arc segment is arranged to form an access tunnel 11 connected to the end 100 a of the widened portion 100.

  Further, from this shield excavator 21, small-section shield excavators 211A to 211G are started, respectively, and a plurality of small-section tunnels 111A to 111G (some are not shown in the figure, as shown in FIG. 2). In order to do so, the illustration of the same form may be omitted.).

  The small-section tunnels 111 </ b> A to 111 </ b> G constructed by the small-section shield excavators 211 </ b> A to 211 </ b> G constitute a part of the small-section tunnel group 10 that becomes the outer shell of the widened portion 100.

  As shown in FIG. 5, the small-section tunnel group 10 is constructed substantially in parallel in the widened portion 100, and the side surfaces of the small-section tunnels 111A to 111G and 121A to 121G constructed in advance are shown in FIG. As shown in FIG. 5, the small-section tunnels 131A to 131G and 141A to 141G adjacent to each other are notched and connected in a state where the cross-sections overlap.

  That is, the lining of these small-section tunnels 111A to 111G, 121A to 121G, 131A to 131G, 141A to 141G (hereinafter, may be described by omitting the alphabet) is cut by the small-section shield excavator 211. It is made of concrete that is strong enough to make it possible.

  Then, the natural ground is surrounded by the small-section tunnel group 10 having an elliptical sectional view constituted by these small-section tunnels 111, 121, 131, 141.

  In addition, it is preferable to arrange a reinforcing bar in a portion that is not cut by the small-section shield excavator 211 when constructing the trailing tunnel.

  Next, a method for constructing the widened portion 100 as the underground structure of the present embodiment will be described, and the operation of this embodiment will be described.

  First, the ground 6 corresponding to the end portions 100a and 100b on both sides in the longitudinal direction of the widened portion 100 is improved by the ground improvement machine 4 from the ground as shown in FIG. The ground improvement machine 4 is a device that stirs and solidifies the natural ground 6 while spraying a solidified material such as cement milk from the tip of the stirring rod 41, for example, and the ground improvement section is deep in the natural ground 6 without excavating the ground. 3A and 3B can be constructed.

  Moreover, if the ground improvement machine 4 is moved on the ground and the ground 6 is improved, the area of the ground that is temporarily occupied can be minimized, compared with the case where a shaft is constructed. The land can be secured relatively easily.

  Then, the shield excavators 21 and 22 are excavated from the ground or starting base (not shown) outside the widened portion 100 toward the one ground improvement portion 3A. The shield excavators 21 and 22 dig up side by side, and access tunnels 11 and 12 are constructed vertically in the shape of an arc when viewed from the side.

  A shallow shaft may be constructed on the ground in order to start the shield excavators 21 and 22. The shaft constructed at this time is small in scale, and a place where the site can be easily secured can be selected. Therefore, it will not interfere with the progress of the construction.

  Moreover, the shield excavators 21 and 22 are provided with a known mechanism for constructing a curved tunnel such as a folding mechanism.

  Further, the shield excavators 23 and 24 are dug up and down from the ground or starting base (not shown) located outside the widened portion 100 opposite to the above toward the other ground improvement portion 3B, On the rear side, the access tunnels 13 and 14 are constructed in an arc shape in a side view.

  These shield excavators 21 to 24 are temporarily stopped before reaching the ground improvement parts 3A and 3B. And as shown in FIG. 2, the small-section shield excavators 211A-211G are started from the shield excavator 21 toward one ground improvement part 3A.

  These small-section shield excavators 211A to 211G are started, for example, in alphabetical order of reference numerals, and are excavated so that the small-section tunnels 111A to 111G spread in a trumpet shape toward the ground improvement portion 3A as shown in FIG.

  When the ground improvement portion 3A is reached, the small-section tunnels 111A to 111G are arranged at predetermined intervals along the ellipse as shown in FIG. 4 (a).

  The intervals of the small cross-section tunnels 111A to 111G are set to be narrower than the diameter of the small cross-section tunnels 111A to 111G so that the side surfaces of the small cross-section tunnels 111A to 111G are connected by a tunnel constructed between them. Keep it.

  Similarly to this shield excavator 21, the shield excavator 22 below is also provided with a small-section shield excavator 221 (hereinafter, the shield excavators 22 to 24 are given the same rules as the shield excavator 21, but are shown in the figure. In some cases, the small-section tunnels 121A to 121G are constructed.

  After these small-section tunnels 111A to 111G and 121A to 121G are arranged in an elliptical shape in sectional view as shown in FIG. 4 (a) in one ground improvement portion 3A, the other ground improvement portions 3B are substantially parallel to each other. It is stretched toward.

  Then, the small section shield excavator 211, 221 is stopped in the ground improvement section 3B, the cutting section 213 on the front surface is collected, and the small section shield excavator 211, 221 of the shield excavator 21, 22 stopped at the rear. Fit into the hole where you started.

  Moreover, the small-section shield excavators 231 and 241 are also started from the shield excavators 23 and 24 stopped before the other ground improvement unit 3B toward the ground improvement unit 3B. The small-section tunnels 131 and 141 extended from these shield excavators 23 and 24 also spread in a trumpet shape as they approach the ground improvement portion 3B, and between the small-section tunnels 111A to 111G and 121A to 121G constructed in advance. It is stretched toward.

  Then, after reaching the ground improvement part 3B, the small-section shield excavators 231A to 231G and 241A to 241G dig up between the small-section tunnels 111A to 111G and 121A to 121G, as shown in FIG. .

  Since the small-section shield excavators 231 and 241 excavate while cutting the side surfaces of the small-section tunnels 111 and 121 constructed in advance, the side surfaces of the small-section tunnels 111, 121, 131, and 141 are connected. The cross section of the small cross section tunnel group 10 is formed in an elliptical shape in which a part of a circular shape overlaps and continues as shown in FIG.

  The cutting section 213 on the front surface of the small-section shield excavators 231 and 241 is also collected after reaching the ground improvement section 3A and is disposed again on the front surfaces of the shield excavators 23 and 24.

  If the cutting part 213 is recovered in this way and returned to the shield excavators 21 to 24 from which the small-section shield excavators 211, 221, 231, and 241 have started, the shield excavators 21 to 24 are directed to the natural ground 6 again. Can dig up.

  Therefore, as shown in FIG. 6, the shield excavators 21 and 22 are excavated from the position (two-dot chain line) where the shield excavators 21 and 22 are stopped toward the ground improvement portion 3A to construct the extending portions 11a and 12a. . In addition, the shield excavators 23 and 24 on the other side are also dug again toward the ground improvement portion 3B to construct the extending portions 13a and 14a (not shown).

  FIG. 7 shows an end face of the widened portion 100 constructed in this way on the one ground improvement portion 3A side.

  The widened portion 100 has an outer shell formed by a small-section tunnel group 10 that surrounds the natural ground 6 in an elliptical cylinder shape, and an end portion 100a of the small-section tunnel group 10 is closed by a ground improvement portion 3A.

  The extended portions 11 a and 12 a of the access tunnels 11 and 12 are connected to the end portion 100 a of the widened portion 100. Here, the covering of the extending portions 11a and 12a is constructed of a material that can be cut by a shield excavator.

  Then, as shown in FIG. 1, the main line shield excavator 25 advances toward the widened portion 100, and the main tunnel 15 becomes the widened portion 100 while cutting the side surfaces of the extending portions 11a and 12a as shown in FIG. Connected.

  Similarly, the main tunnel (not shown) and the access tunnels 13 and 14 are connected to the other end 100b of the widened portion 100.

  In addition, the natural ground 6 surrounded by the small-section tunnel group 10 and the ground improvement portions 3A and 3B in this way is separated from the surrounding natural ground 6 and can be excavated safely and easily with a backhoe or the like. be able to.

  Then, the widened portion 100 is formed by spraying concrete on the inner surface side of the small-section tunnel group 10 exposed by the internal excavation, constructing a reinforced concrete wall separately, or providing a support column or a support beam. What is necessary is just to complete the internal structure.

  In the construction method of the widened portion 100 of the present embodiment configured as described above, the shield excavator 21 including a plurality of small-section shield excavators 211A to 211G is excavated to a predetermined depth of the natural ground 6 and The small-section tunnel group 10 is constructed by connecting a plurality of small-section tunnels 111A to 111G constructed by starting these small-section shield excavators 211A to 211G.

  As described above, since the widened portion 100 surrounding the natural ground 6 can be constructed by the small-section tunnel group 10 without constructing a shaft, an increase in site problems, construction costs and construction period that occur when a shaft is constructed. The construction of the widened section 100 such as a station building is not limited by such problems.

  Further, the cutting portions 213 of the small-section shield excavators 211A to 211G used for the construction of the small-section tunnel group 10 are collected, and the cuts collected by the shield excavator 21 from which these small-section shield excavators 211A to 211G are started. By returning the part 213, the shield excavator 21 can be advanced again.

  Moreover, since the small-section shield excavators 211, 221, 231, 241 may be dug in a substantially horizontal direction and an oblique direction, as in the case of construction of a normal shield tunnel, they are dug upward and turned upside down. There is no need to perform special excavation such as turning back, and posture control is easy and workability is excellent.

  Furthermore, since the workability is good, the small cross-section tunnels 111, 121, 131, 141 can be constructed at accurate positions, and no gap is generated between the small cross-section tunnels 111, 121, 131, 141 due to construction errors. .

  And since there are many processes that can be performed in parallel, such as construction of access tunnels 11 to 14, construction of small-section tunnels 111, 121, 131, and 141, construction of ground improvement sections 3A and 3B, construction of main tunnel 15, The construction period can be shortened.

  Although the best embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes that do not depart from the gist of the present invention are possible. Are included in the present invention.

  For example, in the above-described embodiment, the small-section tunnel group 10 is formed in a cylindrical shape. However, the present invention is not limited to this. Can do.

  Furthermore, the number of small cross-section tunnels 111, 121, 131, 141 constituting the small cross-section tunnel group 10 in the above embodiment is merely an example, and is not limited to this. An appropriate number may be set according to the size and the cross-sectional shape of the intermediate structure.

  In the embodiment, the side surfaces of the small-section tunnels 111 and 121 constructed in advance are cut and connected by the small-section shield excavators 231 and 241 of the subsequent small-section tunnels 131 and 141. For example, a half-moon-shaped small-section tunnel in which a part of a circle is missing is constructed on both sides of a small-section tunnel having a circular section in the first construction, or a weight in which both sides of a circle are missing. A method may be used in which a small-sized tunnel having a shape is constructed and connected.

  Furthermore, in the above-described embodiment, the ground 6 corresponding to the end portions 100a and 100b on both sides in the longitudinal direction of the widened portion 100 is first improved by the ground improvement machine 4 from the ground, but is not limited thereto. The ground improvement portions 3A and 3B may be constructed by injecting chemical solution from the inside of the shield excavators 21 and 22 or the small-section shield excavator.

  In addition, the ground improvement parts 3A and 3B are constructed before excavation of the internal ground 6 surrounded by the small-section tunnel group 10 with a backhoe or the like, except when there is an obstacle to the recovery of the cutting part 213. Just do it.

It is a side view explaining the schematic structure of the underground structure of the best embodiment of this invention. It is a perspective view explaining schematic structure of a shield excavator provided with a plurality of small section shield excavators. It is explanatory drawing explaining the construction process of the ground improvement part in the construction method of an underground structure. It is a figure explaining the method of constructing a wide part, Comprising: (a) is sectional drawing of the small cross-section tunnel constructed | assembled ahead, (b) is sectional drawing of a small cross-section tunnel group. It is a top view near the edge part of the wide part which constructed | assembled the small cross-section tunnel to follow between the preceding small cross-section tunnels. It is explanatory drawing explaining the process of re-digging a shield excavator and building an extending | stretching part. It is sectional drawing explaining the structure of the end surface of a wide part.

Explanation of symbols

100 Widening part (underground structure)
100a, 100b End 10 Small section tunnel group 11, 12, 13, 14 Access tunnel 111, 121, 131, 141 Small section tunnel 21, 22, 23, 24 Shield excavator 211, 221, 231, 241 Small section shield excavation Machine 213 Cutting part 6 Ground

Claims (2)

In the construction method of an underground structure that surrounds a natural ground by a small cross-sectional tunnel group connecting between side surfaces of a plurality of small cross-sectional tunnels, and excavates and constructs the surrounded natural ground,
After digging a shield excavator having a plurality of small-section shield excavators, stop the shield excavator before reaching one of the ends of the underground structure in the longitudinal direction. A plurality of small-section shield excavators are started toward the one end, and after passing through the one end, the small-section shield excavator is dug until reaching the other end. The other end portion is constructed by constructing a shield excavator having a plurality of small section shield excavators from the opposite side of the shield excavator similarly to the other end portion. The shield excavator is stopped before reaching the position, and a plurality of small-section shield excavators are started between the small-section tunnels, and small-section tunnels are constructed between the previously constructed small-section tunnels. Connected between sides Method for constructing underground structures and forming a cross-section tunnel group.   After constructing the small cross-section tunnel, the cutting portion of the front surface of the small cross-section shield excavator is collected, and the collected cutting portion is disposed on the front surface of the shield excavator from which the small cross-section shield excavator is started, The construction method for an underground structure according to claim 1, wherein the shield excavator is advanced again.

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