Concrete box for open shield construction

Abstract

To provide a concrete box for an open shield method which can be laid without generating cracks or breaks on or near connection end faces of the concrete box, not only for an open shield method concrete box with a thin wall and a smooth connection end face used under conditions where a thrust reaction force is large, but also for a normal seal box type concrete box for open excavation and a concrete box with flexibility of individual boxes having earthquake resistance.SOLUTION: A concrete box 4 receives thrust reaction force of a thrust jack of an open shield machine 1 through a push angle 8, and a steel plate 18a against which the push angle 8 abuts is supported by a support member 18b provided on the inside of the concrete box 4 and installed inside the front end of the concrete box 4.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an open shield method for constructing underground structures such as water supply and sewerage systems and underground tunnels in urban areas, and to a concrete box used therein. [Background technology]

[0002] The following patent document describes a concrete box for open shield construction that has connecting parts used in the cut-and-cover method but can also be used in the open shield method, and that can prevent cracks from occurring or corners from breaking even when subjected to the load caused by pushing with a thrust jack. [Patent Document 1] Patent No. 5960785

[0003] As shown in Figures 9 and 10, the concrete box 4 is made of reinforced concrete and consists of a left side panel 4a, a right side panel 4b, an upper floor panel 4c, and a lower floor panel 4d. It is a roughly rectangular tube with openings 4e on the front and rear ends, and a connecting part 116 is formed at the rear end and a connected part 117 is formed at the other end.

[0004] The connecting portion 116 is a male member having a generally square cylindrical shape with a thin-walled portion 116a having a step toward the rear, and the connected portion 117 is a female member having a generally square cylindrical shape with an inner circumference longer than the outer circumference of the connecting portion 116 and with a recess 117a formed on its inner circumference that can fit into the outer peripheral surface of the thin-walled portion 116a of the connecting portion 116.

[0005] The press bar (press angle) 110 is made of H-shaped steel, which can be attached and detached by fitting into the female member of the connected portion 117 at the front end of the concrete box 4.

[0006] Of the flanges 119, 120 of the H-shaped steel 118, half of the flange 119 on one side is missing, and the remaining flange 120 serves as a front end surface cover plate for the female member, and the remaining half (web 121 and flange 119) serves as the engagement portion for the inner circumference of the female member.

[0007] The portion that engages with the inner periphery of this female member is notched in a radiused shape so that the top and bottom can engage with the radiused corners of the inner periphery of the female member of the concrete box 4.

[0008] A steel plate that is longer in the vertical direction than the flange 120 is overlapped on the front surface of this engagement portion as the abutment plate 125. The abutment plate 125 protrudes vertically, and its upward protrusion length is such that it protrudes above the upper floor plate 4c of the concrete box 4, and the hoisting steel material 122 is provided here.

[0009] In addition, the engaging members 23 for engaging with the inner surfaces of the left and right plates 4a and 4b of the concrete box 4 are attached horizontally to the webs 121 that become the engaging portions for the inner circumference of the female member. A short H-shaped steel is used for the engaging members 123.

[0010] Furthermore, the engaging member 123 is provided with a bar receiver 124 made of a channel material.

[0011] The press bars (push corners) 110 are arranged in a set, one on each side, and can be attached and detached by fitting into the female member of the connected portion 117 at the front end of the concrete box 4. The hook receivers 124 face toward the inside of the concrete box 4, and a pipe or the like can be placed here as a hook to strengthen the fitting.

[0012] Next, the method of use will be explained. As described above, the press bar 110 is used to distribute the thrust of the shield jack and transmit it to the concrete box 4.

[0013] In the open shield method using an open shield machine, an excavator excavates and removes soil from the front or top of the front machine, and the shield machine moves forward, suspending the second concrete box 4 into the tail section in front of the first concrete box 4. Thereafter, the same process of excavating and setting the concrete boxes 4 is repeated to successively bury the concrete boxes 4 vertically in the ground.

[0014] The press bar (press corner) 110 is set on the front side of the concrete box 4 to be suspended and lowered into the tail section, either before or after it is suspended. The tail section moves forward by extending the thrust jack (shield jack) and using the concrete box 4 as a reaction force. At that time, the press bar 110 is fitted into the female member on the front end face of the concrete box 4, and the flange 120 covers the outer surface of the thin-walled recess 117a, so that the occurrence of cracks and damage to the corners can be prevented even when the load caused by the thrust jack is applied.

[0015] After the open shield machine has been advanced, the hooks are removed from the hook holders 124, removed from the concrete box 4 and lifted upward in preparation for being set on the next concrete box 4. Summary of the Invention [Problem to be solved by the invention]

[0016] In Patent Document 1, the smooth surface side of the press bar, which is the steel frame, faces the open shield machine and receives the thrust reaction force from the shield jack, so that the entire cross section of the recess side of the cut-and-cover concrete box can receive the thrust reaction force of the open shield machine. Therefore, it becomes possible to lay a cut-and-cover concrete box using the open shield machine.

[0017] However, when the end face of the inro-shaped cut-and-cover concrete box is fitted with the end face of the convex part of another concrete box into its end face on the concave side, the tip of the end face of the concave part and the tip of the end face of the convex part do not abut and a certain distance is maintained so that a specified joint distance can be secured.

[0018] Therefore, the vertical dimensional accuracy of the recess end face and the smoothness of the vertical surface are not taken into consideration. Therefore, depending on the smoothness of the vertical direction and surface unevenness, etc., depending on the manufacturing accuracy of the steel frame press bar and the recess, etc., there may be some parts of the steel frame press bar that are not in contact, and local stress due to the thrust reaction force may occur and concentrate at the contact points, resulting in cracks or concrete breaks at the contact points.

[0019] In other words, the reaction force of the open shield machine propulsion is not evenly distributed to the entire contact area of ​​the recess of the concrete box via the steel frame press bar, increasing the possibility of cracks occurring.

[0020] The object of the present invention is to eliminate the disadvantages of the above-mentioned conventional examples and to provide a concrete box for open shield construction which is used under conditions where a large thrust reaction force is received and which can be laid without the occurrence of cracks or breaks at or near the connecting end faces of the concrete box, not only for concrete boxes for open shield construction which have a thin wall thickness and a smooth connecting end face, but also for ordinary inro-shaped concrete boxes for open cutting and concrete boxes in which the individual boxes have been made flexible and have earthquake-resistant performance. [Means for solving the problem]

[0021] In order to achieve the above object, the present invention described in claim 1 is a concrete box that receives the thrust reaction force of the thrust jack of the open shield machine through a thrust angle, and a steel plate that the thrust angle abuts is provided inside the concrete box. The concrete box is supported by inserts installed at predetermined positions on the inner surface of the box using channel steel or H-shaped steel, and is supported by inserting and fixing bolts into the inserts. The gist of the system is that it is installed inside the front end of the concrete box.

[0022] According to the present invention described in claim 1, the reaction force transmission member supported by a support member provided inside the concrete box abuts against the push angle, so that the rear surface of the push angle does not abut against the end surfaces of both side plates on the front side of the leading concrete box, and the thrust reaction force associated with the extension of the shield jack is transmitted to the concrete box.

[0023] In other words, the thrust reaction force of the open shield machine does not act on the end faces of both side walls of the leading concrete box of the tail section, but is transmitted to the rear inside the concrete by support members inside the leading concrete box.

[0024] Therefore, even in concrete boxes with relatively thin walls under conditions where a large thrust reaction force is expected to act, or ingot-shaped concrete boxes for open-cutting, there is no need to worry about cracks or breaks in the end surfaces of the side slabs, and the thrust reaction force associated with the thrust of the open shield machine can be reliably transmitted to the leading concrete box.

[0025] The present invention as described in claim 2 is characterized in that the steel plate with which the push angle abuts is perpendicular to the support member.

[0026] According to the present invention as described in claim 2, the relative orientation of the steel plate and the support member against which the push angle abuts is taken into consideration, and the steel plate can fully receive the thrust reaction force associated with the extension of the shield jack through the push angle, and the force can be transmitted to the support member, which is a reaction force transmission member, and received by the concrete box.

[0027] The present invention as described in claim 3 is characterized in that the steel plate against which the push angle abuts is positioned so as to extend forward from the front end of the concrete box.

[0028] According to the present invention described in claim 3, the steel plate against which the push angle abuts is located forward of both side slab surfaces of the front surface of the leading concrete box in the tail section, so that it can be reliably ensured that the rear surface of the push angle does not abut against the end surfaces of both side slabs of the front surface of the leading concrete box. Effect of the Invention

[0029] As described above, the concrete box body for open shield construction of the present invention is used under conditions where it is subjected to large thrust reaction forces, and can be laid not only in concrete boxes for open shield construction which have thin walls and smooth connection end faces, but also in ordinary inro-shaped concrete boxes for open cut construction and concrete boxes in which each box body has been made flexible and has earthquake-resistant performance, without the occurrence of cracks or breaks on the connection end faces of the concrete box or in their vicinity.

[0030] Therefore, it is possible to safely and reliably lay concrete boxes or inro-shaped cut-and-cover concrete boxes with smooth connecting end surfaces and relatively small wall thicknesses under conditions in which a large thrust reaction force is expected to act, without causing cracks or breaks on the end faces of the concrete boxes or in their vicinity, while maintaining the specified joint spacing. [Brief description of the drawings]

[0031] [Figure 1] 1 is a cross-sectional plan view showing one embodiment of a concrete box for an open shield construction method according to the present invention. FIG. [Diagram 2] FIG. 2 is a view taken along line AA in FIG. [Diagram 3] 1 is a vertical cross-sectional side view showing one embodiment of a concrete box for an open shield construction method according to the present invention. FIG. [Figure 4] 1 is a cross-sectional plan view showing the installation status of a connecting member of a joint portion between a concrete box body for an open shield construction method of the present invention and a concrete box body behind it. FIG. [Diagram 5] 1 is a longitudinal sectional side view showing the installation status of a connecting member of a joint portion between a concrete box body for an open shield construction method of the present invention and a concrete box body behind it. FIG. [Figure 6] FIG. 2 is a front view of a concrete box for use in the open shield construction method of the present invention. [Figure 7] FIG. 7 is an enlarged view of part A in FIG. 6. [Figure 8] FIG. 2 is a perspective view of a concrete box for the open shield construction method. [Figure 9] FIG. 11 is a cross-sectional plan view showing a conventional example. [Figure 10] FIG. 11 is a vertical sectional side view showing a conventional example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] The embodiments of the present invention will be described in detail below with reference to the drawings. Although each drawing shows a concrete box for cut and cover construction with a spigot-shaped construction, the components shown in the drawings can also be applied to concrete boxes with smooth connection end faces, so the drawings are omitted.

[0033] FIG. 1 is a cross-sectional plan view showing one embodiment of a concrete box for open shield construction of the present invention, in which 1 is an open shield machine, which is composed of a front section 1a with an open top and consisting of left and right side wall panels and a bottom slab connected to these side wall panels, and a tail section 1b with an open top and consisting of left and right side panels and a bottom slab like the front section 1a.

[0034] A sliding retaining plate 6 extending forward is attached to the left and right cutting edges of the open shield machine 1, and propulsion jacks (not shown) extending from the rear end of the front section 1a toward the tail section 1b are arranged in a row facing rearward, one above the other.

[0035] In the open shield machine 1, the tail section 1b is fitted into the rear end of the front section 1, and a center bend section 2 is formed at the fitting section, making it possible to carry out curved construction.

[0036] In the figure, reference numeral 18 denotes a reaction force transmission member which is attached to the leading concrete box 4 which is suspended from the tail section 1b of the open shield machine 1, and which consists of a flat steel plate 18a which abuts against the rear face of the push bar 8, and a support member 18b which protrudes rearward from the rear face and abuts against the inner faces of both side walls of the leading concrete box 4, and the steel plate 18a is supported by the support member 18b which is attached inside the concrete box.

[0037] In this manner, the reaction force transmission member 18 is an assembly of separate members, the steel plate body 18a and the support member 18b.

[0038] The steel plate 18a against which the push angle 8 abuts is provided perpendicular to the support member 18b and is reinforced with a flange or the like.

[0039] The support members 18b are made of channel steel or H-shaped steel, and are firmly fixed by inserts 20 inserted into the inserts that are installed in advance at predetermined positions across each face of the inner surface of the concrete box 4.

[0040] In addition, the steel plate 18a against which the push angle abuts may be provided flush with the front end of the concrete box 4, but is preferably positioned so that it projects slightly forward of the front end of the concrete box 4.

[0041] In this manner, when the propulsion jack is extended during propulsion of the open shield machine 1 and the push angle 8 is pressed rearward, the rear surface of the push angle 8 is pressed against the steel plate 18 a of the reaction force transmission member 18 .

[0042] The force is then transmitted from inside the leading concrete box 4 to the rear through the fixing bolts 20 and inserts 19 that fix the reaction force transmission member 18 via the steel plate 18a and support members 18b that constitute the reaction force transmission member 18, and is further transmitted rearward in sequence via the connecting members 21 that are cross-bridged and fixed to each joint section. It does not act on the end faces of both side walls of the leading concrete box 4 in the tail section.

[0043] Due to the above-described mechanism for transmitting the thrust reaction force, even if a concrete box with a relatively thin wall thickness or a seal-shaped excavation concrete box is laid as the leading concrete box 4 that abuts against the push angle 8 under conditions where a large thrust reaction force is expected to act, there is no risk of cracks or breaks occurring in the end surface of the side slab, and the thrust reaction force can be safely transmitted to such concrete boxes using the open shield machine 1.

[0044] In addition, by making the reaction force transmission member 18 an assembly of divided members, the work of fixing the reaction force transmission member 18 to the installed box body 4 can be done manually without using a loading machine such as a crane. In the figure, 27 denotes a bolt for connecting the divided members of the reaction force transmission member 18 together.

[0045] H-shaped steel beams or channel steel beams were installed as connecting members 21 at the connecting joints between the leading concrete box body 4 and the following concrete box bodies 4 .

[0046] The connecting member 21 is installed so as to span across the joints with the concrete box 4 that contact the rear end face of the leading concrete box 4, and at each joint of the top, side and bottom plates on the inner surface of each of the rear concrete box bodies 4, while maintaining a predetermined joint spacing. The connecting member 21 is provided with holes for inserting fixing bolts 20. The connecting member 21 is firmly fixed by inserting the fixing bolts 20 into inserts 19 that are installed in advance at predetermined positions across each surface of the inner surface of the concrete box.

[0047] As a result of the above, the thrust reaction force is not transmitted to the connection end faces of the joints between the concrete boxes 4, so there is no risk of cracks or breakage occurring at the connection end faces. It also becomes possible to safely lay a spigot-shaped cut-and-cover box. [Explanation of symbols]

[0048] 1...Open shield machine 1a...Front part 1b…Tail section 2…Bent section 3...Propulsion jack (shield jack) 4...Concrete box 4a...Left side plate 4b...Right side version 4c...Top version 4d…bottom plate 4e…opening 4f… Haunch section 6… Sliding retaining plate 8...Press bar (press angle) 9...Water stop bar 14...Sheath hole 17...Backfilling injection material 18...Reaction force transmission member 18a...Steel plate body 18b... Support member 19... Insert 20... Fixing bolt 21... Connection member 24...Grout hole 27...Reaction force transmission member connecting bolt 30…Joint

Claims

1. A concrete box for open shield construction that receives the thrust reaction force of the thrust jack of an open shield machine through a push angle, characterized in that the steel plate against which the push angle abuts is supported by support members made of channel steel or H-shaped steel provided inside the concrete box, and is installed inward at the front end of the concrete box by inserting and fixing bolts into inserts installed at predetermined positions horizontally on each of the inner surfaces of the concrete box.

2. 2. A concrete box structure for an open shield construction method according to claim 1, wherein the steel plate with which the push angle abuts is perpendicular to the support member.

3. 3. A concrete box structure for an open shield construction method according to claim 1 or 2, wherein the steel plate with which the push angle abuts is disposed so as to extend forward from the front end of the concrete box structure.

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