Construction methods for underground structures

The method addresses the inefficiencies of existing underground construction by using a box-shaped roof and traction cable system to safely propel concrete casings without excavation, reducing costs and improving safety.

JP7873521B2Active Publication Date: 2026-06-12UEMURA ENG
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Patent Information

Authority / Receiving Office
JP · JP
Patent Type
Patents
Current Assignee / Owner
UEMURA ENG
Filing Date
2024-05-28
Publication Date
2026-06-12

AI Technical Summary

Technical Problem

Existing methods for constructing large underground structures transversely under railways or roads require separate protective structures like pipe roofs, leading to increased labor costs, construction periods, and safety risks due to excavation work at the tunnel face.

Method used

A construction method involving a box-shaped roof that is pressed into the ground with a concrete casing, using a traction cable and reaction force receiving propulsion body plate to propel the concrete casing forward, eliminating the need for separate excavation and allowing simultaneous propulsion and towing of the box-shaped roof and concrete casing.

Benefits of technology

This method reduces construction costs and time by eliminating dangerous excavation work, improves safety, and enables smooth propulsion of the concrete casing even in spaces with insufficient reaction force, thus enhancing overall construction efficiency.

✦ Generated by Eureka AI based on patent content.

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Patent Text Reader

Abstract

The present invention provides a method for constructing an underground structure in which a box-shaped roof is assembled and placed so as to correspond to the outer shape of a concrete box body to be propelled and then press-fitted into the ground from a start pit, after which a leading-end part of the concrete box body is placed at an end part of the box-shaped roof, and sediment on the face is pushed out together with the box-shaped roof as the concrete box body is towed. With this method, the concrete box body can be towed and propelled safely even in places where it is not possible to provide a sufficient reaction force body in front of the concrete box body to be towed.　A propulsion body panel for receiving reaction force is installed behind a floor plate of the concrete box body, and a tow cable, one end of which is fastened to a side wall of a front bitt of the floor plate of the concrete box body, is laid out on the floor plate portion of the concrete box body and made to penetrate inside the propulsion body panel for receiving reaction force. The other end of the tow cable is anchored to a towing jack installed on a lateral surface of the propulsion body panel for receiving reaction force. The concrete box body tows the tow cable by means of the towing jack, and this towing pushes out the propulsion body panel for receiving reaction force together with the concrete box body.
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Description

Technical Field

[0001] The present invention relates to a construction method for an underground structure that can be constructed without disturbing the upper traffic when tunneling and constructing a large underground structure in the transverse direction under railways, roads, etc.

Background Art

[0002] In order to tunnel a large underground structure in the transverse direction under railways, roads, etc., a protective structure for supporting the upper traffic is required, such as providing a pipe roof in which steel pipes are horizontally arranged in parallel.

[0003] However, since the pipe roof is first formed as a separate construction and the excavation is carried out therein to construct the underground structure, or the underground structure is tunneled under the pipe roof, the soil cover becomes thicker by the amount of the pipe roof. Moreover, the protective structure for the pipe roof construction is a separate construction from the main construction of the underground structure embedding, and the labor cost and construction period are large.

[0004] To solve such inconveniences, as shown in Patent Document 1 below, a box-shaped roof, which is a cylindrical body for the roof, is arranged, and while alternately repeating the forward movement of the box-shaped roof and the forward movement of the concrete casing, a construction method for an underground structure in which the box-shaped roof that has reached the arrival pit is sequentially removed is proposed. Furthermore, to evolve this and solve the following drawbacks of Patent Document 1, Patent Documents 2 and 3 below were filed and patents were obtained.

Patent Document 1

Patent Document 2

Patent Document 3

[0005] The drawbacks of Patent Document 1 are as follows. i) Since the box-shaped roofs are sequentially pushed forward one by one, it takes time and effort until the box-shaped roofs have all advanced. ii) After the box-shaped roof is advanced, the face is excavated before the concrete box body is advanced. Therefore, the excavation of the face is performed between the advancement of the box-shaped roof and the advancement of the concrete box body, requiring excavation work separate from the jacking work of the concrete box body 9. This not only increases construction costs but also extends the construction period accordingly. iii) Excavation work at the tunnel face involves risks such as tunnel face collapse, and ground improvement work such as stabilization treatment to stabilize the tunnel face was also necessary.

[0006] Patent documents 2 and 3 describe a method in which, after press-fitting a box-shaped roof, the concrete box is propelled forward. As the concrete box is propelled forward, the soil at the tunnel face is pushed out together with the box-shaped roof. This eliminates the need for separate excavation work at the tunnel face, thereby reducing costs and shortening the construction period. Furthermore, safety is improved by eliminating the dangerous excavation work at the tunnel face. Moreover, by distributing the reaction force resistance required to propel the concrete box, large-scale equipment is not required.

[0007] The invention described in Patent Document 2 involves arranging a push jack and struts as propulsion equipment between the rear reaction wall of the concrete box and the push jack, and extending the push jack to push the concrete box forward. The invention described in Patent Document 3 involves pushing the concrete box forward by traction.

[0008] Compared to the invention of Patent Document 2, which pushes out a concrete box using a push jack, the invention of Patent Document 3, which pushes out a concrete box by traction, has the advantage of being able to push out a concrete box over a long distance and stably without being affected by the stroke of the push jack.

[0009] The invention described in Patent Document 3, as shown in Figure 35, involves constructing a launching tunnel 3 and a receiving tunnel 4 using retaining steel sheet piles 2, and arranging a box-shaped roof 6 in a rectangular shape to correspond to the outer shape of the concrete box body 9. In this case, the friction cutter plate 7 is placed on the side of the ground, allowing for separation of the box-shaped roof 6 and concrete box body 9 from the surrounding soil.

[0010] In the diagram, 17 is a bracing member, and 19 is a retaining member. The retaining member 19 can be used by partially removing the retaining steel sheet pile 2 with a mirror cut, and is fixed with a tie rod member 18 that connects the retaining steel sheet pile 2 on the launching shaft 3 side and the retaining steel sheet pile 2 on the receiving shaft 4 side.

[0011] A reaction body 21 made of natural ground is provided on the side of the access tunnel 4, and a reaction wall 23 is provided in front of the reaction body 21.

[0012] As propulsion equipment for the concrete box 9, a push jack 10 and struts 16 are installed at the rear of the concrete box 9. 20 indicates the launching platform.

[0013] As a propulsion system for the concrete box structure 9, a traction jack 24 is installed on the reaction wall 23, and the other end of a traction cable 25, one end of which is attached to the traction jack 24, is anchored to an anchoring device 26 attached to the rear of the concrete box structure 9. A center-hole jack can be used for the traction jack 24, and although not shown in the figure, the anchoring device 26 consists of a cone and an anchoring plate.

[0014] Alternatively, the traction jack 24 and the anchoring device 26 may be swapped, with the traction jack 24 attached to the rear of the concrete box 9, and the other end of the traction cable 25, one end of which is attached to the traction jack 24, being anchored to the anchoring device 26 fixed to the reaction wall 23.

[0015] The main pushing jack 10 is extended, and at the same time the pulling jack 24 is activated, and the concrete box body 9 is pulled by the pulling cable 25 from the launching shaft 3 towards the receiving shaft 4, pushing the concrete box body 9 forward.

[0016] As the concrete box body 9 is extruded, the box-shaped roof 6 is also extruded simultaneously. Furthermore, without excavating the face, the retaining wall member 19, which is placed in the area enclosed by the box-shaped roof 6, is extruded at the same time as the box-shaped roof 6 is extruded, thereby simultaneously extruding the soil 29 in front of it. In this case, as described above, the friction cutter plate 7 separates the box-shaped roof 6 and concrete box body 9 from the surrounding soil, so the box-shaped roof 6 and concrete box body 9 advance smoothly.

[0017] As the concrete box 9 moves forward, a strut 16 is positioned between the concrete box 9 and the rear reaction wall 8 to secure the thrust length of the main jack 10.

[0018] In this manner, once the box-shaped roof 6 and the soil and sand that have been simultaneously pushed out while surrounded by the box-shaped roof 6 reach the receiving pit 4, the box-shaped roof 6 is removed in the receiving pit 4, and at the same time, the soil and sand are excavated and removed.

[0019] Then, the concrete box structure 9 is advanced until its tip reaches the receiving shaft 4, completing the advancement of the entire length of the concrete box structure 9.

[0020] As described above, according to the invention of Patent Document 3, the soil at the tunnel face is pushed out at the tip of the concrete box body together with the box-shaped roof. Therefore, the propulsion of the box-shaped roof and the propulsion and towing of the concrete box body can be carried out simultaneously, eliminating the conventional excavation process at the tunnel face that occurred between the propulsion of the box-shaped roof and the propulsion of the concrete box body, thereby reducing construction costs and shortening the construction period. In addition, the elimination of dangerous excavation work at the tunnel face improves construction safety.

[0021] Furthermore, since the concrete box structure is pushed and pulled along with the excavated soil at the excavation face, the reaction force resistance required to move the concrete box structure can be distributed compared to cases where only the concrete box structure is pushed or only it is pulled, and the reaction force at each location can be small. As a result, auxiliary methods such as ground improvement, which are required when the resistance earth pressure is insufficient, are unnecessary, and the costs and construction time for these auxiliary methods are reduced.

Summary of the Invention

Problems to be Solved by the Invention

[0022] In the invention of Patent Document 2, in order to tow a concrete casing, a reaction body by the natural ground was provided on the arrival pit side.

[0023] The construction of such a reaction body by the natural ground is impossible without sufficient space on the arrival pit side, and it also becomes a large-scale construction including the installation of a reaction wall. Moreover, the towing cable passes from the reaction body through the enclosure of the box-shaped roof to reach the concrete casing, and inevitably becomes long, and there is a risk that the towing operation may become unstable.

[0024] The object of the present invention is to eliminate the disadvantages of the above-mentioned conventional examples, and even in a place where it is impossible to provide a sufficient reaction body in front of the concrete casing to be towed, the concrete casing can be safely towed and propelled. Also, since the earth and sand at the face are pushed out at the tip of the concrete casing together with the box-shaped roof, the propulsion of the box-shaped roof, the propulsion and towing of the concrete casing can be carried out simultaneously, and the excavation process of the face that conventionally existed during the process of propelling the concrete casing can be omitted, resulting in cost reduction and construction period shortening. In addition, by eliminating the excavation work of the face that involves danger, the present invention provides a construction method for underground structures that improves the construction safety.

Means for Solving the Problems

[0025] In order to achieve the above object, the invention according to claim 1 is a construction method of an underground structure in which a box-shaped roof is arranged corresponding to the outer shape of the concrete casing to be propelled, and after being pressed into the ground from the starting pit, the tip of the concrete casing is arranged at the end of the box-shaped roof, and the earth and sand at the face are extruded together with the box-shaped roof while pulling the concrete casing. In this method, a reaction force receiving propulsion body plate is installed behind the floor slab of the concrete casing, a traction cable having one end locked to the front bit side wall of the floor slab of the concrete casing is arranged in the floor slab portion of the concrete casing, penetrated through the reaction force receiving propulsion body plate, and the other end of this traction cable is fixed to a traction jack installed on the side surface of the reaction force receiving propulsion body. The concrete casing pulls the traction cable with the traction jack, and the gist is that the reaction force receiving propulsion body plate is extruded together with the concrete casing by this traction.

[0026] According to the present invention described in claim 1, since a reaction force receiving propulsion body plate is installed behind the floor slab of the concrete casing and the concrete casing is pulled with the reaction force receiving propulsion body plate by the traction jack, there is no need to provide a reaction force body by the natural ground on the side of the arrival pit in front of the concrete casing. Furthermore, since all the traction work can be carried out behind the concrete casing, the influence on the surrounding area such as the natural ground is small, and construction can be carried out safely.

[0027] The invention according to claim 2 is that the concrete casing is constructed on a launching pad, and the launching pad has its sides raised to form side guide concrete for the concrete casing.

[0028] According to the present invention described in claim 2, in order to advance the concrete casing by traction, it is guided by the side guide concrete provided on the launching pad, so it can advance safely in the proper direction without bending.

[0029] The invention according to claim 3 is that the arrangement of the traction cable on the floor slab portion of the concrete casing is to embed a traction cable insertion box in the concrete casing during the construction of the concrete casing and insert it through the traction cable insertion box.

[0030] According to the present invention as described in claim 3, a traction cable, with one end secured to the front bit side wall of the floor slab of a concrete box, can be reliably and safely installed in the floor slab portion of a concrete box by embedding a traction cable insertion box in the concrete box during construction and inserting the traction cable through the insertion box.

[0031] The present invention as described in claim 4 is characterized in that the traction cable insertion box consists of a top lid that moves together with the concrete box and a main body into which this top lid fits.

[0032] According to the present invention as described in claim 4, when inserting a towing cable into a towing cable insertion box and arranging it on the floor plate portion of a concrete box, the towing cable insertion box has a top lid that moves with the concrete box, while the main body remains in place, so the concrete box can be moved without dragging the towing cable.

[0033] The present invention as described in claim 5 is characterized by installing a lubricant injection device inside a concrete box and injecting lubricant into the bottom of the concrete box using the lubricant injection device when the concrete box moves forward.

[0034] According to the present invention as described in claim 5, by injecting a lubricant into the bottom of the concrete box when the concrete box is moving forward, the frictional resistance of the concrete box moving forward is reduced, allowing for smooth towing. [Effects of the Invention]

[0035] As described above, the construction method for underground structures of the present invention allows for the safe towing and propulsion of a concrete box even in locations where a sufficient reaction force can not be provided in front of the towed concrete box. Furthermore, since the soil at the tunnel face is pushed out at the tip of the concrete box together with the box-shaped roof, the propulsion of the box-shaped roof and the propulsion and towing of the concrete box can be carried out simultaneously. This eliminates the conventional excavation process at the tunnel face that occurred during the propulsion process of the concrete box, resulting in reduced construction costs and shorter construction periods. Additionally, the elimination of dangerous excavation work at the tunnel face improves construction safety. [Brief explanation of the drawing]

[0036] [Figure 1] This is a longitudinal cross-sectional side view showing the first step of the construction method for underground structures according to the present invention. [Figure 2] This is a plan view showing the first step of the construction method for underground structures according to the present invention. [Figure 3] This is a longitudinal cross-sectional side view showing the second step of the construction method for underground structures according to the present invention. [Figure 4] This is a plan view showing the second step of the construction method for underground structures according to the present invention. [Figure 5] This is a longitudinal cross-sectional side view showing the third step of the construction method for underground structures according to the present invention. [Figure 6] This is a plan view showing the third step of the construction method for underground structures according to the present invention. [Figure 7] This is a longitudinal cross-sectional side view showing the fourth step of the construction method for underground structures according to the present invention. [Figure 8] This is a plan view showing the fourth step of the construction method for underground structures according to the present invention. [Figure 9] This is a longitudinal cross-sectional side view showing the fifth step of the construction method for underground structures according to the present invention. [Figure 10] This is a plan view showing the fifth step of the construction method for underground structures according to the present invention. [Figure 11] This is a longitudinal cross-sectional side view showing the sixth step of the construction method for underground structures according to the present invention. [Figure 12] This is a plan view showing the sixth step of the construction method for underground structures according to the present invention. [Figure 13]This is a longitudinal cross-sectional side view showing the seventh step of the construction method for underground structures according to the present invention. [Figure 14] This is a plan view showing the seventh step of the construction method for underground structures according to the present invention. [Figure 15] This is a longitudinal cross-sectional side view showing the eighth step of the construction method for underground structures according to the present invention. [Figure 16] This is a plan view showing the eighth step of the construction method for underground structures according to the present invention. [Figure 17] This is a longitudinal cross-sectional side view showing the ninth step of the construction method for underground structures according to the present invention. [Figure 18] This is a plan view showing the ninth step of the construction method for underground structures according to the present invention. [Figure 19] This is a longitudinal cross-sectional side view showing the 10th step of the construction method for underground structures according to the present invention. [Figure 20] This is a plan view showing the tenth step of the construction method for underground structures according to the present invention. [Figure 21] This is a longitudinal cross-sectional side view showing the 11th step of the construction method for underground structures according to the present invention. [Figure 22] This is a plan view showing the 11th step of the construction method for underground structures according to the present invention. [Figure 23] This is a longitudinal cross-sectional side view showing the 12th step of the construction method for underground structures according to the present invention. [Figure 24] This is a plan view showing the 12th step of the construction method for underground structures according to the present invention. [Figure 25] This is a longitudinal cross-sectional side view showing the 13th step of the construction method for underground structures according to the present invention. [Figure 26] This is a plan view showing the 13th step of the construction method for underground structures according to the present invention. [Figure 27] This is a longitudinal cross-sectional side view showing the 14th step of the construction method for underground structures according to the present invention. [Figure 28] This is a plan view showing the 14th step of the construction method for underground structures according to the present invention. [Figure 29] This is a longitudinal cross-sectional side view showing the 15th step of the construction method for underground structures according to the present invention. [Figure 30] This is a plan view showing the 15th step of the construction method for underground structures according to the present invention. [Figure 31]This is a cross-sectional view along line AA in Figure 10. [Figure 32] This is a cross-sectional view along line AA in Figure 12. [Figure 33] This is a detailed view of section a in Figure 13. [Figure 34] Figure 14 is a cross-sectional view along line BB. [Figure 35] This is a longitudinal cross-sectional view showing a conventional example. [Best Mode for Carrying Out the Invention]

[0037] The embodiments of the present invention will be described in detail below with reference to the drawings. Figures 1 to 30 are longitudinal cross-sectional side views and plan views of each step of the construction method for underground structures of the present invention, and the same reference numerals are used for components that are the same as those in the conventional example shown in Figure 35.

[0038] First, let me explain the equipment. In the diagram, 2 is a retaining steel sheet pile, which uses sheet piles or H-shaped steel. This retaining steel sheet pile 2 is for constructing the launching tunnel 3 and the receiving tunnel 4.

[0039] In the figure, 6 is a box-shaped roof, which, although not shown in the illustration, is a box-shaped cylindrical body with a roughly square cross-section, with hook-shaped joints continuously formed along the longitudinal direction on the side, and a friction cutter plate 7 superimposed on the top or side surface.

[0040] This box-shaped roof 6 has connecting flanges at the front and rear ends and can be connected sequentially by bolting in the longitudinal direction to bury the required length, and can also be arranged in parallel in a continuous manner in the longitudinal and transverse directions via hook-shaped joints.

[0041] The box-shaped roof 6 is arranged in a rectangular shape to correspond to the outer shape of the concrete box body 9. At this time, the friction cutter plate 7 is placed on the side of the ground, which allows for separation of the box-shaped roof 6 and concrete box body 9 from the surrounding soil.

[0042] The concrete box structure 9 is a reinforced concrete structure that forms the underground structure to be constructed, and is a cylindrical box culvert consisting of a floor plate 9a, a top plate, and left and right side plates.

[0043] In the diagram, 20 is a launching platform formed by concrete pouring, and the concrete box structure 9 is constructed on top of this launching platform 20. The sides of the launching platform 20 are raised to form side guide concrete 20a for the concrete box structure.

[0044] In the figure, 30 is a reaction force receiving propulsion plate installed behind the floor slab 9a of the concrete box body 9. It is constructed of reinforced concrete, with its front end formed as a vertical surface that abuts against the concrete box body 9, and its rear end formed as an inclined surface for installing the traction jack 24. Multiple of these reaction force receiving propulsion plates 30 are installed side by side with spacing between them.

[0045] The towing jack 24 is a center-hole type jack that pulls the towing cable 25. Although not shown in the diagram, it has a wedge-shaped cone and a fixing plate.

[0046] As shown in Figures 3 and 4, a steel sheet pile 2 is driven into the ground next to an overhead transport structure 31 such as a railway to construct a launching tunnel 3 and a receiving tunnel 4. A frame 32 is assembled inside the launching tunnel 3, and a box-shaped roof 6 is placed on top of it. The steel sheet pile 2 is opened in a mirror-like shape, and the box-shaped roof 6 is passed through it and pressed in from the launching tunnel 3 towards the receiving tunnel 4.

[0047] The box-shaped roof 6 is pressed into place using a propulsion jack 33, spacers 34, and struts 35. Workers inside the box-shaped roof 6 manually excavate using the tip of the cutting edge, the excavated soil is sent to the rear on a trolley, and the box-shaped roof 6 is pushed forward using the propulsion jack 33 in the area that has been excavated.

[0048] A friction cutter plate 7 is attached to the top surface of the box-shaped roof 6, which is a cylindrical body for the roof, as in the conventional method, and is extruded together with the box-shaped roof 6.

[0049] Once the box-shaped roof 6 for the upper floor section is in place, the support frame 32 is removed, and then the box-shaped roof 6 for the lower floor section is in place, followed by the box-shaped roof 6 for the left and right wall sections. The box-shaped roofs 6 are arranged in a rectangular shape to correspond to the outer shape of the concrete box 9 that is to be propelled.

[0050] The interior of this box-shaped structure enclosed by the rectangular roof 6 contains soil, and portions of the retaining steel sheet piles 2, cut in a mirror-cut manner, can be used as retaining wall members 19 at the front and rear. These retaining wall members 19 at the front and rear may be fixed to each other with tie rods.

[0051] The retaining wall member 19 and the box-shaped roof 6 are fixed together with temporary fastening members 27. In the launching shaft 3, a pit 36 ​​is constructed directly below the rear end of the box-shaped roof 6 for fixing the towing members. Crushed stone is laid on the bottom surface of the launching shaft 3, and concrete is poured on top of it to construct the launching platform 20. (See Figures 9 and 10)

[0052] As described above, the launch platform 20 has raised sides to form side guide concrete 20a for the concrete box body, and a guide plate 37 made of strip steel plate is laid on the inside of this side guide concrete 20a.

[0053] The concrete box structure 9 is constructed on the launch platform 20 of the launch shaft 3. When constructing the concrete box structure 9, one end of the traction cable 25 is secured to the side wall of the bit 36 ​​in front of the floor plate 9a of the concrete box structure 9 using a fixing device, and the traction cable 25 is extended and positioned on the floor plate 9a portion of the concrete box structure 9. In order to pull the traction cable 25 through the side wall of the bit 36 ​​to the top surface of the launch platform 20, a sheath pipe 46 is embedded in the launch platform 20, and the cable is inserted through it.

[0054] The traction cable 25 was placed on the floor plate 9a portion of the concrete box 9 by embedding a traction cable insertion box 38 into the concrete box 9 during its construction and inserting the traction cable through the insertion box 38.

[0055] The traction cable insertion box 38 consists of a top lid 38a that moves together with the concrete box 9 and a main body 38b into which the top lid 38a fits. The top lid 38a is provided with dowel bars 39 as protrusions at appropriate intervals, and the dowel bars 39 act as stud dowels to maintain integration with the floor plate 9a portion of the concrete box 9.

[0056] Before constructing the concrete box 9, a lubricant was applied to the upper surface of the launch platform 20, and a separation sheet was installed, laying the lubricant and the separation sheet 40 between the traction cable insertion boxes 38.

[0057] Furthermore, when constructing the concrete box body 9, the dowel reinforcement bars 39 are placed on top of the steel plates at appropriate intervals, and the box body jacking steel plates 41 are arranged in a strip-like fashion, spaced apart, in positions that avoid the areas where lubricant is injected. These are laid between the traction cable insertion boxes 38, and the concrete box body 9 is constructed on top of them, so that the concrete box body 9 contains the box body jacking steel plates 41 at its bottom surface. (See Figure 18)

[0058] As shown in Figures 19 and 20, a reaction force receiving thrusting platform 30 is constructed behind the floor plate 9a of the concrete box structure 9. A traction cable 25, which is installed on the floor plate 9a portion of the concrete box structure 9, is extended and passed through the reaction force receiving thrusting platform 30, and then inserted through a traction jack 24 provided on the reaction force receiving thrusting platform 30 to secure it in place.

[0059] Furthermore, a connecting steel member 42, which is a rectangular frame made of H-shaped steel, is placed on the front end surface of the concrete box body 9. In addition, a lubricant injection device 43 is installed on the floor plate 9a portion inside the concrete box body 9, and a lubricant injection pipe 44 is pre-positioned in the floor plate 9a portion so as to penetrate it vertically and exit to the bottom.

[0060] The traction jack 24 is activated to push the concrete box 9 forward via the reaction force receiving propulsion plate 30. (Dry pushing) At this time, lubricant is injected into the bottom of the concrete box 9 from the lubricant injection device 43.

[0061] The concrete box body 9 and the box-shaped roof 6 are connected via the connecting steel members 42, and the friction cutter plates 7 positioned on the top, sides, and bottom of the concrete box body 9 are connected to the friction cutter plates 7 installed on the box-shaped roof 6 via the friction cutter plate fixing girders 45.

[0062] This friction cutter plate 7 is used to separate the box-shaped roof 6 and concrete box structure 9 from the surrounding soil.

[0063] The towing jack 24 is activated, and the towing cable 25 pulls the reaction force receiving propulsion plate 30 and the concrete box 9 from the launching shaft 3 towards the arrival shaft 4, pushing the concrete box 9 forward.

[0064] Simultaneously with the extrusion of the concrete box structure 9, the box-shaped roof 6 is also extruded. Furthermore, without excavating the face, the earth retaining members 19 installed in the area enclosed by the box-shaped roof 6 are extruded at the same time as the box-shaped roof 6 is extruded.

[0065] In this case, as described above, the friction cutter plate 7 separates the box-shaped roof 6 and concrete box 9 from the surrounding soil, allowing the box-shaped roof 6 and concrete box 9 to move smoothly.

[0066] In this manner, when the box-shaped roof 6 and the soil 29 that are simultaneously pushed out while surrounded by the box-shaped roof 6 reach the receiving pit 4, the box-shaped roof 6 is removed in the receiving pit 4, and at the same time, the soil 29 is excavated and removed.

[0067] Then, the concrete box 9 is advanced until its tip reaches the receiving shaft 4, completing the advancement of the entire length of the concrete box 9. (See Figures 29 and 30.) Furthermore, if there are more boxes to be advanced, the reaction force receiving thrusting plate is returned to the back of the launching shaft, and the process from Figure 16 to Figure 27 is repeated. [Explanation of symbols]

[0068] 2. Steel sheet piles for earth retention 3. Launch shaft 4 Reaching shaft 6 Box-shaped roof 7 Friction cutter plate 8. Reaction wall 9. Concrete box 9a Floorboard 10 Main push jack 14 Retaining member 16 Strut 17. Bracing material 18. Tie rod material 19 Retaining wall members 20 Launch platform 20a Side guide concrete 21 Reaction body 23 Reaction wall 24 Towing jack 25. Traction cable 26. Fixing device 27 Temporary fastening member 29 Soil and sand 30 Reaction force receiving propulsion body panel 31 Upper traffic 32. Mounting frame 33. Propulsion jack 34 Spacer 35 Strut 36 Pit 37 Guide Plate 38 Towing cable insertion box 38a Top cover 38b Main body 39 Girdle muscle 40 Lubricant and edge-cutting sheet 41 Steel plate for box-type propulsion 42 Connecting steel members 43 Lubricant injection device 44 Lubricant injection tube 45 Friction cutter plate fixing beam 46 Sheathed tube

Claims

1. In a construction method for underground structures, a box-shaped roof is assembled and positioned to correspond to the outer shape of the concrete box to be propelled, and after being pressed into the ground from a launching shaft, the leading edge of the concrete box is positioned at the end of the box-shaped roof, and the soil at the excavation face is pushed out together with the box-shaped roof as the concrete box is to be pulled, the construction method for underground structures is characterized in that a reaction force receiving jacking plate is installed behind the floor plate of the concrete box, a traction cable is arranged on the floor plate portion of the concrete box with one end secured to the front bit side wall of the floor plate of the concrete box, and is passed through the reaction force receiving jacking plate, the other end of the traction cable is fixed to a traction jack installed on the side of the reaction force receiving jacking, and the concrete box is pulled by the traction jack along with the traction cable, and this traction pushes out the reaction force receiving jacking plate together with the concrete box.

2. A method for constructing an underground structure according to claim 1, wherein the concrete box body is constructed on a launching platform, and the launching platform has its sides raised to form side guide concrete for the concrete box body.

3. The method for constructing an underground structure according to claim 1, wherein the traction cable is placed in the floor slab portion of the concrete box body by embedding a traction cable insertion box in the concrete box body during construction and inserting the traction cable through the insertion box.

4. A method for constructing an underground structure according to claim 3, wherein the traction cable insertion box comprises a top lid that moves together with the concrete box and a main body into which the top lid fits.

5. A method for constructing an underground structure according to claim 1, wherein a lubricant injection device is installed inside the concrete box, and the lubricant is injected into the bottom of the concrete box by the lubricant injection device when the concrete box moves forward.