Method for constructing connecting structures and underground structures

Abstract

To provide a connection structure suitably connecting a wall surface of a retention wall and an end part of a slab of a SC structure to each other.SOLUTION: A connection structure 50 connecting an inner wall surface 5a of a retention wall 5 and an end part 4a of a pile cap 4a of a SC structure is provided with: first steel plates 51a, 51b arranged on an inner wall surface 5a of the retention wall 5 and extending toward the end part 4a of the pile cap 4 from the inner wall surface 5a of the retention wall 5; second steel plates 52a, 52b arranged on the end part 4a of the pile cap 4 and extending toward the inner wall surface 5a of the retention wall 5 from the end part 4a of the pile cap 4; and concrete installed so as to include the first steel plates 51a, 51b and the second steel plates 52a, 52b. The first steel plates 51a, 51b and the second steel plates 52a, 52b faces to each other with a gap therebetween and in the gap concrete is installed.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a structure for connecting a wall surface of a retaining wall and an end portion of a slab to each other, and a method for constructing an underground structure including this connecting structure.

Background Art

[0002] As a structure for connecting a retaining wall such as a steel sheet pile wall and a slab of an RC structure (reinforced concrete structure) to each other, for example, the technique disclosed in Patent Document 1 can be cited.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, for example, in a situation where a slab is constructed under an open head restriction, it may be required to reduce the thickness of the slab (that is, to make it thinner). In this case, it is conceivable to achieve such thinning by making the slab a SC structure (steel frame concrete structure) instead of an RC structure.

[0005] However, when connecting the wall surface of the retaining wall and the end portion of the slab of the SC structure to each other, since a technique premised on using reinforcing bars, such as the technique disclosed in Patent Document 1, cannot be directly applied, there has been room for consideration.

[0006] In view of such a situation, an object of the present invention is to propose a method for suitably connecting the wall surface of a retaining wall and the end portion of a slab of a SC structure to each other.

Means for Solving the Problems

[0007] Therefore, the connecting structure according to the present invention is a structure that connects the wall surface of an earth retaining wall to the end of a slab made of SC structure. This connecting structure comprises a first steel plate provided on the wall surface of the earth retaining wall and extending from the wall surface of the earth retaining wall toward the end of the slab, a second steel plate provided at the end of the slab and extending from the end of the slab toward the wall surface of the earth retaining wall, and concrete poured so as to wrap around the first and second steel plates. The first and second steel plates face each other with a gap between them, and the concrete is also poured into this gap.

[0008] The method for constructing an underground structure according to the present invention includes forming a pilot tunnel underground, constructing a retaining wall extending downward from the pilot tunnel and constructing a pipe roof extending laterally from the pilot tunnel, forming an underground space by excavating within the area partitioned by the pipe roof and the retaining wall, and constructing a slab within this underground space. Here, constructing the slab includes connecting the wall surface of the retaining wall and the end of the slab to form the aforementioned connecting structure.

[0009] In this invention, "SC structure" means "steel-reinforced concrete structure," which may include so-called "steel-concrete composite structures." Here, the members constituting the steel frame may include, for example, steel plates (including flat steel) and shaped steel materials (for example, H-shaped steel materials and I-shaped steel materials). [Effects of the Invention]

[0010] According to the present invention, the wall surface of the retaining wall and the end of the SC structure slab can be suitably connected to each other. [Brief explanation of the drawing]

[0011] [Figure 1] Cross-sectional view showing the schematic configuration of an underground structure in one embodiment of the present invention. [Figure 2] This figure shows the method for constructing an underground structure in the above embodiment. [Figure 3] This figure shows the method for constructing an underground structure in the above embodiment. [Figure 4] This figure shows the method for constructing an underground structure in the above embodiment. [Figure 5] A perspective view showing the connection structure between the retaining wall and the top plate in the above embodiment. [Figure 6] Cross-sectional view showing the connection structure between the retaining wall and the top slab in the above embodiment. [Figure 7] Cross-sectional view AA in Figure 6 [Figure 8] BB cross-section view in Figure 6 [Figure 9] This figure shows the second steel plate which is integrated with the main girder in the above embodiment. [Figure 10] Cross-sectional view of CC in Figure 6 [Figure 11] DD cross-section view in Figure 6 [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described below with reference to the drawings.

[0013] Figure 1 is a cross-sectional view showing the schematic configuration of an underground structure in one embodiment of the present invention. In this embodiment, a culvert 1 is given as an example of an underground structure and will be described below. For convenience, in the following description, the extension direction (axial direction) of the culvert 1 is defined as the front-to-back direction, and the left-to-right and up-and-down directions are defined as shown in Figure 1. Furthermore, the portion P shown in Figure 1 corresponds to Figures 5 and 6, which will be described later.

[0014] The culvert 1 has, for example, a rectangular cross-section and extends underground (below the ground surface GL). The culvert 1 includes a bottom slab 2, a pair of left and right side walls 3, 3, and a top slab 4. In this embodiment, the bottom slab 2 is of RC structure (reinforced concrete structure). The side wall 3 has a two-layer structure consisting of a retaining wall 5 forming the outer part and an inner wall 6 forming the inner part. In this embodiment, the retaining wall 5 is a steel sheet pile wall (steel sheet pile continuous wall). In this embodiment, the inner wall 6 is of RC structure. The structural form of the side wall 3 composed of the retaining wall 5 and the inner wall 6 may be any of the so-called double wall method, integral wall method, and single wall method. In this embodiment, the top slab 4 is of SC structure (steel-concrete composite structure). Here, the top slab 4 in this embodiment corresponds to an example of the "slab made of SC structure" of the present invention.

[0015] In this embodiment, when constructing the culvert 1 underground, for example, due to circumstances such as the existence of existing structures on the ground surface GL, the excavation method cannot be applied. Therefore, the construction method shown in FIGS. 2 to 4 is adopted to construct the culvert 1.

[0016] First, as shown in FIG. 2(a), a pair of left and right pilot tunnels 10, 10 are excavated and formed underground. Note that although the cross-sectional shape of the pilot tunnel 10 shown in FIG. 2(a) is rectangular, it goes without saying that it may be any shape such as circular or elliptical.

[0017] Next, as shown in FIG. 2(b), the retaining wall 5 is constructed so as to extend downward from each pilot tunnel 10. Also, a pipe roof 11 as a temporary roof is constructed so as to straddle between the pilot tunnels 10, 10. Here, the timing of constructing the retaining wall 5 and the timing of constructing the pipe roof 11 may be the same or may be shifted from each other.

[0018] In this embodiment, the retaining wall 5 is a steel continuous underground wall (steel continuous wall) and is composed of steel continuous wall members 15 (see Figures 5 and 6 described later) erected downward from the pilot tunnel 10. These steel continuous wall members 15 are parallel flange type steel retaining wall members, with fitting joints provided at both ends of the inner flange 15a and outer flange 15b. For the construction of the retaining wall 5, a method may be adopted in which the ground is excavated downward from the pilot tunnel 10 using a stabilizing fluid excavation method to form a trench, the steel continuous wall members 15 are erected in this trench, and then concrete or the like is filled in, or the stabilizing fluid is solidified. Alternatively, a method may be adopted in which the steel continuous wall members 15 are erected in soil cement created downward from the pilot tunnel 10 using an in-situ soil mixing method.

[0019] Next, as shown in Figure 3(c), an underground space 12 is formed by excavating within the area (in other words, the enclosed area) demarcated by the left and right retaining walls 5,5 and the pipe roof 11. During this excavation, any part of the pilot tunnel 10 that obstructs the formation of the underground space 12 may be removed. Figure 3(c) also shows the floor surface 13.

[0020] Next, as shown in Figure 3(E), the RC structure base slab 2 and inner wall 6 are constructed within the underground space 12 above the floor surface 13. Note that in Figure 3(E), for the sake of simplicity, the reinforcing bars 20 (see Figures 5 and 6), which will be described later, are not shown.

[0021] Next, as shown in Figure 4(e), the top slab 4 is constructed (the top slab 4 is spanned) within the underground space 12, straddling the left and right retaining walls 5 and the inner wall 6. The top slab 4 is composed of a plurality of box-shaped steel units 41-43 (see Figures 5 and 6) and concrete (not shown) poured into these steel units 41-43. In this embodiment, the top slab 4 is constructed by sequentially assembling the steel units 41, 42, and 43 from both ends toward the center in the left-right direction, and then pouring concrete into this assembly. The construction of the top slab 4 can be carried out sequentially in the front-rear direction. Here, each of the steel units 41-43 is manufactured, for example, in a factory above ground, and transported from the factory through the pilot tunnel 10 to the planned construction site of the top slab 4. For this reason, each of the steel units 41-43 is sized to pass through the pilot tunnel 10.

[0022] Here, the steel frame units 41 that constitute the left and right ends of the top plate 4 have second steel plates 52 (52a, 52b) that constitute the connecting structure 50, which will be described later. The connecting structure 50 is constructed at the same time as the top plate 4 is constructed (that is, the retaining wall 5 and the top plate 4 are connected to each other).

[0023] Next, as shown in Figure 4(k), the portion 12a between the upper surface of the top slab 4 and the lower surface of the pipe roof 11 in the underground space 12 is backfilled with fluidized soil or the like. The space 10a inside the pilot tunnel 10 is also backfilled with fluidized soil or the like. In this way, culvert 1 is constructed.

[0024] Next, the connecting structure 50 between the retaining wall 5 and the top slab 4 will be explained using Figures 5 to 8. Figure 5 is a perspective view showing the connection structure 50 between the retaining wall 5 and the top slab 4. Figure 6 is a cross-sectional view showing the connection structure 50 between the retaining wall 5 and the top slab 4. Figure 7 is a cross-sectional view AA of Figure 6. Figure 8 is a cross-sectional view BB of Figure 6. Note that in Figure 7, the studs 21, which will be described later, are not shown for the sake of illustration simplicity.

[0025] The connecting structure 50 comprises a plurality of first steel plates 51 extending from the inner wall surface (the wall surface facing the underground space 12) 5a of the retaining wall 5 toward the top plate 4, a plurality of second steel plates 52 provided at the end 4a of the top plate 4 (specifically, the end 41a of the steel frame unit 41 constituting the top plate 4 (the end facing the retaining wall 5)) and extending from this end 4a toward the inner wall surface 5a of the retaining wall 5, and concrete (not shown) poured so as to wrap around the first steel plates 51 and the second steel plates 52.

[0026] In this embodiment, the first steel plate 51 and the second steel plate 52 are each arranged in multiple layers (two layers in this embodiment) in the vertical direction. Here, in this embodiment, the upper layer of the first steel plate 51 is designated as the first steel plate 51a, and the lower layer is designated as the first steel plate 51b. Similarly, the upper layer of the second steel plate 52 is designated as the second steel plate 52a, and the lower layer is designated as the second steel plate 52b. The first steel plate 51 and the second steel plate 52 are not limited to two layers vertically, but may be three or more layers vertically, or they may be just one layer vertically.

[0027] In this embodiment, multiple first steel plates 51a are arranged in a comb-like pattern in a plan view, and multiple first steel plates 51b are also arranged in a comb-like pattern in a plan view (see Figure 7). Similarly, multiple second steel plates 52a are arranged in a comb-like pattern in a plan view, and multiple second steel plates 52b are also arranged in a comb-like pattern in a plan view (see Figure 7). The comb-like arrangement of multiple first steel plates 51a and multiple comb-like arrangement of multiple second steel plates 52a is arranged to interlock with gaps between them in a plan view. Similarly, the comb-like arrangement of multiple first steel plates 51b and multiple comb-like arrangement of multiple second steel plates 52b is arranged to interlock with gaps between them in a plan view (see Figure 7). Therefore, the first steel plates 51a and the second steel plates 52a face each other with gaps between them, and the aforementioned concrete can be poured into these gaps. Similarly, the first steel plates 51b and the second steel plates 52b face each other with gaps between them, and the aforementioned concrete can be poured into these gaps.

[0028] In this embodiment, the inner wall surface 5a of the retaining wall 5 is the exposed surface of the inner flange 15a of the steel bridging wall member 15 to the underground space 12. Therefore, the base end of the first steel plate 51a and the base end of the first steel plate 51b are fixed to the inner flange 15a of the steel bridging wall member 15 by welding or the like. Bearing plates 51c are attached to the tip of the first steel plate 51a and the tip of the first steel plate 51b, respectively. It is preferable that the respective tip ends of the first steel plates 51a and 51b are positioned adjacent to the base ends of the second steel plates 52a and 52b (and the end 41a of the steel frame unit 41).

[0029] As shown in Figures 5 to 7, the steel wall member 15 is provided with multiple reinforcing plates 15c that straddle the inner flange 15a and the outer flange 15b. The reinforcing plates 15c are made of steel, and both ends are fixed to the inner flange 15a and the outer flange 15b by welding or the like, respectively. It is preferable that the reinforcing plates 15c be arranged in a straight line with the first steel plates 51a and 51b in a front view (see Figure 6) and a plan view (see Figure 7).

[0030] Multiple reinforcing bars 51d are fixed to the first steel plates 51a and 51b (particularly the portion facing the aforementioned gap) by welding or other means to create irregularities. These reinforcing bars 51d serve as means for increasing adhesion (irregularities) to increase the adhesion force between the first steel plates 51a and 51b and the concrete. Alternatively, multiple through holes may be formed in the first steel plates 51a and 51b, and these through holes may also be used as means for increasing adhesion. In other words, at least one of these through holes and the reinforcing bars 51d can be used as means for increasing adhesion.

[0031] As shown in Figure 8, multiple studs 21 are fixed by welding or the like in the region between the installation location of the upper first steel plate 51a and the installation location of the lower first steel plate 51b on the inner wall surface 5a of the retaining wall 5 (the exposed surface of the inner flange 15a of the steel retaining wall member 15 to the underground space 12). These studs 21 serve as means to increase the adhesion force between the retaining wall 5 and the concrete. Alternatively, perforated steel plate dowels may be provided in the region and used as the means to increase the adhesion force. In other words, at least one of the perforated steel plate dowels and the studs 21 can be used as the means to increase the adhesion force.

[0032] In this embodiment, the second steel plates 52a and 52b protrude laterally from the end portion 41a of the steel frame unit 41. It is preferable that the respective tip portions (protruding ends) of the second steel plates 52a and 52b are positioned adjacent to the base portions of the first steel plates 51a and 51b (and the inner flange 15a of the steel continuous wall member 15). Here, the tip portion of the second steel plate 52a and the tip portion of the second steel plate 52b may each be fitted with bearing plates similar to the bearing plate 51c described above.

[0033] Multiple reinforcing bars 52d are fixed to the second steel plates 52a and 52b (particularly the portion facing the aforementioned gap) by welding or other means to create irregularities. These reinforcing bars 52d serve as means for increasing adhesion (irregularities) to increase the adhesion force between the second steel plates 52a and 52b and the concrete. Alternatively, multiple through holes may be formed in the second steel plates 52a and 52b, and these through holes may also be used as means for increasing adhesion. In other words, at least one of these through holes and the reinforcing bars 52d can be used as means for increasing adhesion.

[0034] In this embodiment, the first steel plates 51a, 51b and the second steel plates 52a, 52b are arranged in parallel so that they leave a predetermined gap between them in a plan view and overlap (overlap) for a predetermined length in a front view, so that the stress generated between the retaining wall 5 and the top plate 4 is effectively transmitted between them via concrete. Here, tensile force can be transmitted between the first steel plate 51a and the second steel plate 52a via concrete. Furthermore, compressive force can be transmitted between the first steel plate 51b and the second steel plate 52b via concrete.

[0035] In this embodiment, in order to deal with the aforementioned tensile force, the height (vertical length) of the upper first steel plate 51a is made greater than the height (vertical length) of the lower first steel plate 51b, so that the contact area between the upper first steel plate 51a and the concrete is greater than the contact area between the lower first steel plate 51b (see Figure 8).

[0036] Next, the details of the second steel plates 52a and 52b will be explained using Figure 9. Figure 9 shows the second steel plates 52a and 52b, which are integrated with the main girders 41b and 41c that constitute the steel frame unit 41.

[0037] In this embodiment, the second steel plates 52a and 52b constituting the connecting structure 50 and the pair of side steel plates 52e and 52f extending in the vertical direction are integrated in a square shape when viewed from the front (see Figures 6 and 9), and furthermore, the second steel plates 52a and 52b are integrated with the main girders 41b and 41c. Therefore, the second steel plates 52a and 52b, the side steel plates 52e and 52f, and the main girders 41b and 41c are all made of a single steel plate. Also, the second steel plates 52a and 52b and the main girders 41b and 41c are aligned in a straight line when viewed from above (see Figure 7).

[0038] Multiple through-holes 52g are formed in at least one of the side steel plates 52e and 52f (side steel plate 52e in this embodiment) to create an uneven surface, and these through-holes 52g serve as means for increasing adhesion to concrete (uneven surface). Alternatively, multiple reinforcing bars may be fixed to at least one of the side steel plates 52e and 52f by welding or the like, and these reinforcing bars may also serve as the means for increasing adhesion. In other words, at least one of the reinforcing bars and the through-holes 52g can be used as the means for increasing adhesion.

[0039] The side steel plates 52e and 52f may be positioned to face the reinforcing bars (main reinforcing bars of the inner wall 6) 20 that protrude upward from the upper end of the inner wall 6, with a gap between them. This can play a role in improving stress transfer between the side steel plates 52e and 52f and the reinforcing bars 20 via the concrete. Furthermore, it is preferable that the aforementioned through-hole 52g is also formed to face the reinforcing bars 20 that protrude upward from the upper end of the inner wall 6, with a gap between them.

[0040] The concrete pouring for the connecting structure 50 can be carried out integrally with (i.e., as a series of operations) the concrete pouring during the construction of the top slab 4.

[0041] A haunch portion is formed on the end 41a side of the steel frame unit 41. A steel frame unit 42 can be connected to the end 41d on the opposite side of the steel frame unit 41 from end 41a. This connection may be made using splice plates or the like, or the units may be connected to each other by welding or the like.

[0042] Figure 10 is a cross-sectional view of the CC shown in Figure 6, illustrating the schematic configuration of the steel frame unit 41. The steel frame unit 41 is composed of a plurality of upper main girders 41b extending horizontally in parallel with spacing in the front-rear direction, a plurality of lower main girders 41c extending horizontally in parallel with spacing in the front-rear direction, an upper skin plate 41e and a lower skin plate 41f forming the outer shell, a plurality of upper longitudinal ribs 41g extending horizontally in parallel with spacing in the left-right direction, a plurality of lower longitudinal ribs 41h extending horizontally in parallel with spacing in the left-right direction, and a joint plate (inter-ring joint plate) 41j. Here, the main girders 41b, 41c, skin plates 41e, 41f, longitudinal ribs 41g, 41h, and joint plate 41j are each made of steel plate and each constitutes a steel frame.

[0043] The upper ends of multiple upper main girders 41b and the upper ends of multiple upper longitudinal ribs 41g are fixed to the lower surface of the upper skin plate 41e by welding or the like. The lower ends of multiple lower main girders 41c and the lower ends of multiple lower longitudinal ribs 41h are fixed to the upper surface of the lower skin plate 41f by welding or the like. Here, the main girders 41b and 41c located furthest forward are integrally formed from a single steel plate 41k for shear reinforcement. Similarly, the main girders 41b and 41c located furthest rear are also integrally formed from a single steel plate 41k for shear reinforcement.

[0044] The joint plates 41j are provided at the front and rear ends of the skin plates 41e and 41f, respectively. Steel frame units 41 adjacent to each other in the front-rear direction can be connected to each other by appropriate connecting means with their respective joint plates 41j in contact with each other.

[0045] In this embodiment, the upper skin plate 41e has an extension portion 41et that extends from the end portion 41a of the steel frame unit 41 toward the inner wall surface 5a of the retaining wall 5 (see Figures 6 and 8). The extension portion 41et can constitute the outer shell (upper surface) of the connecting structure 50. The extension portion 41et may have injection holes formed through it for injecting concrete that constitutes the connecting structure 50. In addition, the upper ends of a plurality of second steel plates 52a may be fixed to the lower surface of the extension portion 41et by welding or the like. Note that the extension portion 41et may be omitted.

[0046] Figure 11 is a cross-sectional view of Figure 6, showing the schematic configuration of the steel frame unit 42. The steel frame unit 42 is composed of an upper skin plate 42a and a lower skin plate 42b that form the outer shell, a plurality of upper longitudinal ribs 42c that extend parallel to each other in the front-to-back direction with spacing in the left-to-right direction, a plurality of lower longitudinal ribs 42d that extend parallel to each other in the front-to-back direction with spacing in the left-to-right direction, a pair of shear reinforcement plates 42e that extend parallel to each other in the left-to-right direction with spacing in the front-to-back direction, and joint plates (inter-ring joint plates) 42f. Here, the skin plates 42a, 42b, the longitudinal ribs 42c, 42d, the shear reinforcement plates 42e, and the joint plates 42f are each made of steel plates and each constitutes a steel frame.

[0047] Multiple upper longitudinal ribs 42c are fixed to the lower surface of the upper skin plate 42a by welding or the like. Multiple lower longitudinal ribs 42d are fixed to the upper surface of the lower skin plate 42b by welding or the like. In addition, a shear reinforcement plate 42e is provided spanning between the skin plates 42a and 42b.

[0048] The joint plates 42f are provided at the front and rear ends of the skin plates 42a and 42b, respectively. Steel frame units 42 adjacent to each other in the front-rear direction can be connected to each other by appropriate connecting means with their respective joint plates 42f in contact with each other.

[0049] The configuration of steel frame unit 43 is the same as that of steel frame unit 42, so its explanation will be omitted. Also, the method of connecting steel frame unit 42 and steel frame unit 43 is the same as the method of connecting steel frame unit 41 and steel frame unit 42, so its explanation will be omitted.

[0050] The top slab 4 is composed of multiple steel frame units 41 to 43, each of which can be manufactured, for example, in an above-ground factory and transported from the factory through the pilot tunnel 10 to the planned construction site of the top slab 4. This significantly reduces the on-site reinforcement work required to construct the top slab 4, and consequently, greatly improves construction efficiency.

[0051] According to this embodiment, the connecting structure 50 that connects the inner wall surface 5a (wall surface) of the retaining wall 5 and the end portion 4a of the top plate 4 (slab) of the SC structure comprises first steel plates 51a, 51b provided on the inner wall surface 5a of the retaining wall 5 and extending from the inner wall surface 5a of the retaining wall 5 toward the end portion 4a of the top plate 4, second steel plates 52a, 52b provided on the end portion 4a of the top plate 4 and extending from the end portion 4a of the top plate 4 toward the inner wall surface 5a of the retaining wall 5, and concrete poured so as to enclose the first steel plates 51a, 51b and the second steel plates 52a, 52b. The first steel plates 51a, 51b and the second steel plates 52a, 52b face each other with a gap between them, and concrete is also poured into the gap. This connecting structure 50 allows the inner wall surface 5a of the retaining wall 5 and the end portion 4a of the top plate 4 of the SC structure to be suitably connected to each other.

[0052] Furthermore, according to this embodiment, the steel main girders 41b, 41c and the second steel plates 52a, 52b that constitute the top slab 4 are integrated, and the main girders 41b, 41c and the second steel plates 52a, 52b are aligned in a straight line in plan view. This allows for smooth stress transfer between the main girders 41b, 41c and the second steel plates 52a, 52b.

[0053] Furthermore, according to this embodiment, reinforcing bars 51d, 52d (adhesion-enhancing means) for increasing adhesion to concrete are provided on at least one of the portions of the first steel plates 51a, 51b facing the aforementioned gap and the portions of the second steel plates 52a, 52b facing the aforementioned gap. This further strengthens the integration of the first steel plates 51a, 51b and the second steel plates 52a, 52b via concrete.

[0054] Furthermore, according to this embodiment, the first steel plate 51 and the second steel plate 52 are each arranged in multiple layers in the vertical direction. The contact area between the uppermost first steel plate 51a and the concrete is larger than the contact area between the lowermost first steel plate 51b and the concrete. This allows for good resistance to the tensile force generated at the top of the connecting structure 50. In addition, to resist the tensile force, the contact area between the uppermost second steel plate 52a and the concrete may be made larger than the contact area between the lowermost second steel plate 52b and the concrete.

[0055] Furthermore, according to this embodiment, a plurality of first steel plates 51a are arranged in a comb-like pattern in a plan view, a plurality of first steel plates 51b are arranged in a comb-like pattern in a plan view, a plurality of second steel plates 52a are arranged in a comb-like pattern in a plan view, and a plurality of second steel plates 52b are arranged in a comb-like pattern in a plan view. By interlocking the comb-like first steel plates 51a and comb-like second steel plates 52a with each other, and further interlocking the comb-like first steel plates 51b and comb-like second steel plates 52b with each other, the connecting structure 50 can be made even stronger.

[0056] Furthermore, according to this embodiment, the top slab 4 of the culvert 1 is given as an example of the slab of the present invention, and the side wall 3 of the culvert 1 includes a retaining wall 5, and this retaining wall 5 is a steel continuous underground wall. Therefore, the retaining wall 5 can be effectively utilized as a component of the culvert 1, that is, as part of the permanent underground structure.

[0057] Furthermore, according to this embodiment, the method for constructing the culvert 1 (underground structure) includes forming a pilot tunnel 10 underground, constructing a retaining wall 5 extending downward from the pilot tunnel 10, constructing a pipe roof 11 extending laterally from the pilot tunnel 10, forming an underground space 12 by excavating within the area partitioned by the pipe roof 11 and the retaining wall 5, and constructing a top slab 4 within the underground space 12. The construction of the top slab 4 includes connecting the inner wall surface 5a (wall surface) of the retaining wall 5 and the end surface 4a of the top slab 4 so as to form the aforementioned connecting structure 50. This makes it possible to construct the culvert 1 underground even in situations where the open-cut method cannot be applied, such as when there is an existing structure above ground level (GL).

[0058] In this embodiment, the inner wall 6 is made of reinforced concrete (RC), but it may also be made of supersonic steel (SC). Alternatively, the inner wall 6 may be omitted, and the side wall 3 may be made only of the retaining wall 5. In these cases as well, it goes without saying that the aforementioned connecting structure 50 between the retaining wall 5 and the top slab 4 can be used.

[0059] In this embodiment, the top slab 4 was given as an example of a slab made of SC structure, but the slab is not limited to the top slab 4, and may be, for example, a bottom slab or a floor slab made of SC structure.

[0060] In this embodiment, an example is shown in which two pilot tunnels 10 are formed underground, but the number of pilot tunnels 10 formed underground is not limited to two. Only one pilot tunnel 10 may be formed, or three or more pilot tunnels 10 may be formed.

[0061] In this embodiment, an example in which the retaining wall 5 is a steel continuous underground wall has been described, but the retaining wall 5 is not limited to a steel continuous underground wall. For the retaining wall 5, it is sufficient that the fixing points of the first steel plates 51 (51a, 51b) on the inner wall surface 5a are made of steel material (e.g., steel plates). In other words, the connecting structure 50 in this embodiment is not only applicable to the retaining wall 5 made of the aforementioned steel continuous underground wall, but is also applicable to retaining walls 5 made of soil-cement continuous walls equipped with core materials such as H-shaped steel materials, formed by methods such as the SMW method or TRD method, or to retaining walls 5 made of steel sheet piles.

[0062] As is clear from the above description, the illustrated embodiments are merely illustrative of the present invention, and it goes without saying that the present invention includes not only those directly shown by the described embodiments, but also various improvements and modifications made by those skilled in the art within the scope of the claims. [Explanation of symbols]

[0063] 1...Culvert, 2...Base slab, 3...Side wall, 4...Top slab, 4a...End, 5...Earth retaining wall, 5a...Inner wall surface, 6...Inner wall, 10...Pilot tunnel, 10a...Space, 11...Pipe roof, 12...Underground space, 12a...Part, 13...Floor surface, 15...Steel interlocking wall member, 15a...Inner flange, 15b...Outer flange, 15c...Reinforcement plate, 20...Reinforcement bar, 21...Stud, 41...Steel frame unit, 41a...End, 41b,41c...Main girder, 41d...End, 41e,41f...Skin Plate, 41et…extension section, 41g, 41h…longitudinal rib, 41j…joint plate, 41k…steel plate, 42…steel frame unit, 42a, 42b…skin plate, 42c, 42d…longitudinal rib, 42e…shear reinforcement plate, 42f…joint plate, 43…steel frame unit, 50…connecting structure, 51, 51a, 51b…first steel plate, 51c…bearing plate, 51d…reinforcement, 52, 52a, 52b…second steel plate, 52d…reinforcement, 52e, 52f…side steel plate, 52g…through hole, GL…ground

Claims

1. A structure that connects the wall surface of an earth retaining wall to the end of a slab made of SC structure, A first steel plate is provided on the wall surface of the retaining wall and extends from the wall surface of the retaining wall toward the end of the slab, A second steel plate is provided at the end of the slab and extends from the end of the slab toward the wall surface of the retaining wall, Concrete poured so as to enclose the first steel plate and the second steel plate, Equipped with, A connecting structure in which the first steel plate and the second steel plate face each other with a gap between them, and the concrete is poured into the gap.

2. The steel main girder and the second steel plate that constitute the slab are integrated, The connecting structure according to claim 1, wherein the main girder and the second steel plate are aligned in a straight line in a plan view.

3. The connecting structure according to claim 1, wherein at least one of the portion of the first steel plate facing the gap and the portion of the second steel plate facing the gap is provided with means for increasing the adhesion force to the concrete.

4. The connecting structure according to claim 1, wherein the first steel plate and the second steel plate are each provided in multiple stages in the vertical direction.

5. The connecting structure according to claim 4, wherein the contact area between the uppermost first steel plate and the concrete is greater than the contact area between the lowermost first steel plate and the concrete.

6. Multiple of the first steel plates are arranged in a comb-like pattern in a plan view. The connecting structure according to claim 1, wherein the multiple second steel plates are also arranged in a comb-like pattern in a plan view.

7. The aforementioned slab is the top slab of the culvert. The connecting structure according to claim 1, wherein the side wall of the culvert includes the earth retaining wall.

8. The aforementioned retaining wall is a steel continuous underground wall, the connecting structure according to claim 1.

9. A method for constructing underground structures, To create a pilot tunnel underground, Construct the earth retaining wall so as to extend downward from the aforementioned tunnel, and construct the pipe roof so as to extend laterally from the aforementioned tunnel. To form an underground space by excavating within the area partitioned by the pipe roof and the retaining wall, To construct the slab within the aforementioned underground space, Includes, A method for constructing an underground structure, comprising constructing the slab by connecting the wall surface of the retaining wall and the end of the slab so as to form the connecting structure described in any one of claims 1 to 8.

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