Inverted arch-free structure and tunnel

Abstract

The utility model provides an inverted-arch-free structure and a tunnel, and relates to the technical field of tunnel construction, the inverted-arch-free structure comprises a surrounding rock, a top arch and a bottom wall, a construction hole is excavated in the surrounding rock, the top arch and the bottom wall are attached to the inner wall of the construction hole, the bottom wall is supported between the top arch and the ground, and the top arch is arranged on the bottom wall. A tunnel portal is defined by the top arch, the bottom wall and the ground, the wall face of the side, facing the surrounding rock, of the bottom wall is vertically downward, the wall face of the side, deviating from the surrounding rock, of the bottom wall is an arc face, the arc face is flush with the edge of the top arch and is concyclic with the edge of the top arch, and the end, close to the ground, of the bottom wall is provided with an expansion arch foot. And the width of the expanded arch springing is greater than the thickness of the top arch. The inverted-arch-free tunnel has the advantages that the inverted-arch-free tunnel is stable in structure and easy to construct.

Description

TECHNICAL FIELD

[0001] The utility model relates to tunnel construction technical field, specifically, relate to a kind of no invert structure and tunnel. BACKGROUND

[0002] Referring to Figure 1 , conventional tunnel often adopts invert design, and the invert 101 refers to the arc-shaped load-bearing structure of the bottom of the cross section of the tunnel main body 10. The invert 101 and the side wall and the semicircular arch 103 form a closed ring, which can effectively resist the surrounding rock pressure and groundwater pressure, and is suitable for being arranged in a section of soft surrounding rock or abundant groundwater. In the IV-type and III-type surrounding rock section with better geological stratum, an invert-free tunnel structure with an open bottom can be selected. The invert-free tunnel can effectively shorten the construction period and reduce the construction cost due to the simple construction technology.

[0003] In the related art, the lining structure of the invert-free tunnel is divided into a top circular arch and a bottom side wall with the invert line as a boundary. The bottom side wall is supported on both sides of the top circular arch, and needs to bear the load conducted from the top circular arch and the lateral earth pressure, and is a very important load-bearing structure in the tunnel. The invert-free tunnel is often divided into a circular arch curved wall structure 20 or a circular arch straight wall structure 30 according to the shape of the lining structure. Figure 2 The bottom side wall 202 of the circular arch curved wall structure 20 is in the form of a circular arc, and has the same diameter as the top circular arch 201. However, the circular arc-shaped bottom side wall 202 has the problems of poor stability and great difficulty in excavating the circular arc-shaped hole opening boundary. Figure 3 The circular arch straight wall structure 30 changes the bottom side wall 302 into a straight line, thereby making up for the above-mentioned defects of the circular arch curved wall structure 20.

[0004] However, at the same time, the circular arch straight wall structure 30 cannot be integrally poured at the joint between the straight wall and the circular arch, and needs to be separately constructed by using a plane formwork for the straight wall section, which not only increases the construction difficulty of the lining structure, but also leads to poor integrity of the structure and easily causes the concrete at the joint to crack. The two existing invert-free structures have adverse effects on the use or construction of the tunnel. SUMMARY

[0005] The problem solved by the utility model is how to make the invert-free tunnel structure stable and easy to construct.

[0006] To solve the above problems, the utility model provides an invert-free structure and tunnel.

[0007] In a first aspect, the utility model provides an invert-free structure, which adopts the following technical scheme:

[0008] A tunnel-like structure without an inverted arch includes surrounding rock, a top arch, and a bottom wall. A construction opening is excavated in the surrounding rock. The top arch and the bottom wall are attached to the inner wall of the construction opening. The bottom wall is supported between the top arch and the ground. The top arch, the bottom wall, and the ground together form a tunnel opening. The side of the bottom wall facing the surrounding rock is a vertically downward straight surface, and the side of the bottom wall away from the surrounding rock is an arc surface. The arc surface is flush with the edge of the top arch and is circular. An enlarged arch foot is provided at the end of the bottom wall near the ground. The width of the enlarged arch foot is greater than the thickness of the top arch.

[0009] The beneficial effects of this utility model are as follows: By improving the existing structure of tunnels without an inverted arch, the side of the bottom wall facing the surrounding rock is made into a vertically downward straight wall, while the side of the bottom wall facing the tunnel entrance is set into an arc surface that is circular with the top arch to form a curved wall. This creates a tunnel without an inverted arch with a curved inner wall and a straight outer wall, combining the advantages of both curved wall and straight wall structures. Compared to the original curved wall structure without an inverted arch, changing the side of the bottom wall closer to the surrounding rock to a straight wall facilitates the excavation of the tunnel entrance. Since the straight wall side of the bottom wall is parallel to the direction of gravity, it is more conducive to maintaining the stability of the surrounding rock and soil after the tunnel entrance is excavated. Designing the inner side of the base wall as an arc surface that is circular with the top arch facilitates the use of circular formwork to cast the top arch and base wall as a single unit during construction. This improves the integrity of the connection between the top arch and the base wall and the quality of the wall construction. Compared to the original straight wall structure without an inverted arch, this invention eliminates the need for additional casting formwork that matches the straight wall. The top arch and the base wall can share a circular casting formwork, thereby simplifying the construction and casting process and significantly improving the integrity of the connection between the top arch and the base wall.

[0010] Optionally, the construction opening is composed of an upper semi-circular opening and a lower rectangular opening. The top arch includes a top support structure, and the bottom wall includes a lateral support structure. The top support structure and the lateral support structure together form the initial support structure. The top support structure is attached to the inner wall of the semi-circular opening, and the lateral support structure is supported between the top support structure and the ground. The lateral support structure is attached to the inner wall of the rectangular opening, and the top support structure and the lateral support structure are fixedly connected.

[0011] Optionally, the initial support structure includes multiple arch frames, and the top support structure and the lateral support structures connected to both sides together form an arch frame, with tie members provided between adjacent arch frames.

[0012] Optionally, both the top support structure and the side support structure are made of steel profiles, and a connecting plate is provided at the connection between the top support structure and the side support structure.

[0013] Optionally, the connecting plate comprises a first plate body and a second plate body, the first plate body is welded and fixed with the top support structure, the second plate body is welded and fixed with the lateral support structure, and the first plate body and the second plate body are bolted.

[0014] Optionally, the bottom end of the top support structure and / or the bottom end of the lateral support structure is provided with an anchoring device for fixedly connecting the primary support structure with the surrounding rock.

[0015] Optionally, the top arch further comprises a circular arch lining structure, and the bottom wall further comprises a springer lining structure, the circular arch lining structure and the springer lining structure jointly constitute a secondary lining structure, the secondary lining structure is arranged in the inside of the primary support structure, the bottom end of the springer lining structure forms the enlarged springer, and the circular arch lining structure and the springer lining structure are integrally formed so that the top arch is coaxial with the curved surface.

[0016] Optionally, the secondary lining structure comprises a reinforcing cage and a masonry layer, the reinforcing cage is glued and fixed in the masonry layer, the reinforcing cage comprises an inside longitudinal reinforcement, an outside longitudinal reinforcement and a constructional reinforcement, the inside longitudinal reinforcement and the outside longitudinal reinforcement are respectively located on both sides of the thickness direction of the masonry layer, the constructional reinforcement is used for connecting the inside longitudinal reinforcement and the outside longitudinal reinforcement, and the inside longitudinal reinforcement and the outside longitudinal reinforcement are bent and shaped along the cross section outer contour of the masonry layer.

[0017] The end of the inside longitudinal reinforcement is bent to form a first bending part at the enlarged springer, the end of the outside longitudinal reinforcement is bent to form a second bending part at the enlarged springer, the first bending part and the second bending part are mutually embraced, the second bending part comprises an embracing section perpendicular to the outside longitudinal reinforcement and a supplementary section parallel to the outside longitudinal reinforcement, one end of the supplementary section away from the embracing section is abutted against the inside longitudinal reinforcement, and the supplementary section is used for making up the longitudinal reinforcement ratio of the enlarged springer part.

[0018] Optionally, a deformation joint is arranged between the primary support structure and the secondary lining structure.

[0019] In the second aspect, the present application provides a tunnel without inverted arch, which adopts the following technical scheme.

[0020] The tunnel without inverted arch comprises the above-mentioned inverted arch structure, and further comprises a road surface structure layer and a trench, the road surface structure layer is located below the tunnel portal, and the trench is arranged between the road surface structure layer and the enlarged springer.

[0021] The tunnel provided by the present application has the same beneficial effects as the inverted arch structure, and thus the beneficial effects of the tunnel without inverted arch will not be described again. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 Figure 1 is a schematic diagram of a cross section of a tunnel structure with inverted arch in the related art.

[0023] Figure 2 Figure 2 is a schematic diagram of a cross section of a tunnel without inverted arch with curved wall in the related art.

[0024] Figure 3 Figure 3 is a schematic diagram of a cross section of a tunnel without inverted arch with straight wall in the related art.

[0025] Figure 4 Figure 4 is a schematic diagram of a tunnel structure without inverted arch according to an embodiment of the present application.

[0026] Figure 5 Figure 5 is a schematic diagram of an initial support structure according to an embodiment of the present application.

[0027] Figure 6 Figure 6 is a schematic diagram of a connection plate according to an embodiment of the present application. Figure 5 Figure 7 is a partial enlarged view of part A in Figure 6.

[0028] Figure 7 Figure 8 is a schematic diagram of a secondary lining structure according to an embodiment of the present application.

[0029] Figure 8 Figure 9 is a schematic diagram of a longitudinal reinforcement structure of a reinforcement cage according to an embodiment of the present application.

[0030] Figure 9 Figure 10 is a schematic diagram of a longitudinal reinforcement structure of a reinforcement cage according to an embodiment of the present application.

[0031] Legend of reference signs:

[0032] 11, tunnel body; 101, inverted arch; 102, side wall; 103, semi-circular arch; 20, curved wall structure with circular arch; 201, top circular arch A; 202, bottom side wall A; 30, straight wall structure with circular arch; 301, top circular arch B; 302, bottom side wall B; 40, ground; 1, surrounding rock; 11, construction opening; 111, semi-circular opening; 112, rectangular opening; 12, mortar anchor rod; 13, drainage hole; 2, top arch; 21, top support structure; 22, circular arch lining structure; 3, bottom wall; 31, lateral support structure; 32, arch foot lining structure; 321, curved surface; 322, enlarged arch foot; 4, tunnel opening; 5, initial support structure; 51, arch frame; 52, tie member; 53, connection plate; 531, first plate body; 532, second plate body; 533, bolt; 54, single-layer connection plate; 6, anchoring device; 7, secondary lining structure; 71, reinforcement cage; 711, inner longitudinal reinforcement; 712, first bending portion; 713, outer longitudinal reinforcement; 714, second bending portion; 7141, embracing section; 7142, supplementary section; 715, structural reinforcement; 72, masonry layer; 8, road surface structure layer; 9, trench; 91, drainage ditch; 92, cable trench. DETAILED DESCRIPTION

[0033] In order to make the above objectives, characteristics and advantages of the present application more apparent, understandable and easier to understand, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms, and should not be interpreted as being limited to the embodiments described herein, but rather, these embodiments are provided in order to more thoroughly and completely understand the present application. It should be understood that the drawings and embodiments of the present application are for exemplary purposes only, and are not intended to limit the scope of protection of the present application.

[0034] The Z-axis in the drawings represents the vertical direction, i.e., the up-down position, and the positive direction of the Z-axis represents the upper side, and the negative direction of the Z-axis represents the lower side; the X-axis in the drawings represents the horizontal direction, and is designated as the left-right position, and the positive direction of the X-axis represents the right side, and the negative direction of the X-axis represents the left side; and the Y-axis in the drawings represents the front-rear position, and the positive direction of the Y-axis represents the front side, and the negative direction of the Y-axis represents the rear side. It should be noted that the meanings of the aforementioned Z-axis, Y-axis and X-axis are only for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be understood as limiting the present application.

[0035] The term "comprising" and variations thereof as used herein are open-ended, that is "including, but not limited to"; the term "based on" is "based, at least in part, on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optional" means "optional in at least some embodiments". Related definitions will be given in the description below. It should be noted that the concepts of "first", "second", etc. mentioned in the present application are only used to distinguish different devices, modules or units, and are not intended to limit the functions performed by these devices, modules or units or the mutual dependency relationship.

[0036] It should be noted that the modification of "one" or "multiple" mentioned in the present application is illustrative rather than limiting, and those skilled in the art should understand that, unless otherwise explicitly indicated in the context, it should be understood as "one or more".

[0037] Reference Figure 2In the related art, the original round-arch curved wall structure 20 in the tunnel without inverted arch includes a top round arch 201 and bottom side walls 202 supported on both sides below the top round arch 201, in order to maintain the integrity of the inner surface of the tunnel, the cross section of the bottom side walls 202 and the top round arch 201 are both round-arched, and they are concentric. According to the mechanical principle, the most stressed part of the bottom side walls 202 is at the lower end, as known, the greater the stress area is, the smaller the stress is, Figure 2 As can be seen from FIG. 1, the bottom side walls 202 have the same thickness as the top round arch 201, and there is eccentricity between the center O point of the contact surface of the bottom side walls 202 and the stress center G point of the bottom side walls 202, in addition, the bottom side walls 202 are also subjected to lateral earth pressure from the surrounding rock, therefore, the bottom end of the bottom side walls A is the most disadvantageous and weakest part in structure, the above structure makes the tunnel have a high stability risk in use, and additional construction and maintenance costs are required to overcome the structural defects. In addition, the curved wall surface excavation is not easy to accurately control the excavation section, and the round-arched bottom side walls 202 also increase the difficulty of excavation opening and surrounding rock support.

[0038] With reference to Figure 3 In the related art, there is another round-arch straight wall structure 30 tunnel without inverted arch, the round-arch straight wall structure 30 includes a top round arch 301 and a bottom side wall 302, the difference between the round-arch straight wall structure 30 and the round-arch curved wall structure 20 is that the bottom side wall 302 is not curved with the arc of the top round arch 301, and the cross section of the bottom side wall 302 is rectangular. The round-arch straight wall structure 30 can solve the problems of eccentric stress and large excavation difficulty of the round-arch curved wall structure 20, but it will cause new problems such as poor structural integrity, poor construction quality of the connection part between the round arch and the straight wall, and the like, and after the bottom side wall 302 is changed to a straight wall, the original round-arch formwork cannot be used during pouring, and a new planar formwork matching the straight wall needs to be replaced, the discontinuous formwork will cause the problem of poor integrated pouring and forming effect of the connection part between the top round arch 301 and the bottom side wall 302. Moreover, special treatment is required for the part of the curved wall to the straight wall during the early excavation and support stage, which further increases the construction difficulty.

[0039] In view of the problems in the above related art, the utility model provides a tunnel without inverted arch structure.

[0040] With reference to Figure 4 , Figure 5In one aspect, the utility model discloses a kind of no invert structure, including surrounding rock 1, top arch 2 and bottom wall 3, the construction opening 11 is excavated on the surrounding rock 1, the top arch 2 and the bottom wall 3 are attached in the inner wall of the construction opening 11, the bottom wall 3 is supported between the top arch 2 and ground 40, the top arch 2, bottom wall 3 and ground 40 are enclosed to form tunnel opening 4, the side wall of the bottom wall 3 towards the surrounding rock 1 is vertical downward straight face, the side wall of the bottom wall 3 away from the surrounding rock 1 is arc surface 321, the arc surface 321 is flush with the edge of the top arch 2 and common circle, the one end of the bottom wall 3 close to ground 40 is equipped with expansion arch foot 322, and the width of the expansion arch foot 322 is greater than the thickness of the top arch 2.

[0041] Specifically, the side wall of the bottom wall 3 towards the surrounding rock 1 is made into vertical downward straight wall, and the wall surface of the bottom wall 3 towards the inside of tunnel is provided as arc surface 321 with the top arch 2 to form curved wall, to form the novel no invert structure of inside curved and outside straight of bottom wall 3, and the no invert structure of inside curved and outside straight of bottom wall 3 has the advantages of circular arch curved wall no invert structure and circular arch straight wall no invert structure. Compared with the original curved wall no invert structure, the side of the bottom wall 3 close to the surrounding rock 1 is changed into straight wall, so that the section contour line is more easily controlled when blasting and excavating construction opening 11, thereby reducing construction difficulty. Since the straight wall side of the bottom wall 3 is parallel to the direction of gravity, the soil body of surrounding rock 1 is more stable after construction opening 11 is excavated, and the expansion arch foot 322 of the bottom wall 3 can increase the stress area and reduce the stress concentration phenomenon at the bottom end of the bottom wall 3, greatly improve the bearing capacity and stability of the structure, and make up the stress defects of circular arch curved wall structure 20 and circular arch straight wall structure 30. And the inside of the bottom wall 3 is provided as arc surface 321 with the top arch 2 to facilitate integrally pouring the top arch 2 and the bottom wall 3 using circular formwork during construction, improve the integrity of the connecting part of the top arch 2 and the bottom wall 3 and wall surface construction quality, compared with the original straight wall no invert structure, the novel no invert structure of inside curved and outside straight does not need to prepare pouring formwork matched with straight wall, the top arch 2 and the bottom wall 3 can share circular pouring formwork, simplify the difficulty of construction pouring, and greatly improve the integrity of the connecting part of the top arch 2 and the bottom wall 3.

[0042] The "+" filled area in the figure represents the surrounding rock 1 soil body. In this embodiment, there is no inverted arch structure and the tunnel centerline is mirror-symmetric. In order to make the drawing more clear, the single-sided drawing commonly used in construction drawings is used to simplify the expression. In this embodiment, the surrounding rock 1 is a good geological condition IV and III surrounding rock 1. In order to prevent the construction opening 11 from collapsing, improve the permeability resistance of the surrounding rock 1, and make the surrounding rock 1 have higher connection strength with the top arch 2 and the bottom wall 3, the mortar anchor rod 12 is vertically arranged on the inner wall of the construction opening 11, and the steel mesh is hung on the inner surface of the construction opening 11. The anchor shotcrete support is used to pretreat the surrounding rock 1. The mortar anchor rod 12 is uniformly distributed along the outer contour of the cross section of the construction opening 11. At the same time, drainage holes 13 are arranged at random positions on the inner wall of the construction opening 11 to facilitate the centralized drainage of underground water in the surrounding rock 1.

[0043] Referring to Figure 5 Optionally, the construction opening 11 is composed of an upper semicircular opening 111 and a lower rectangular opening 112, the top arch 2 comprises a top supporting structure 21, the bottom wall 3 comprises a lateral supporting structure 31, the top supporting structure 21 and the lateral supporting structure 31 jointly form an initial supporting structure 5, the top supporting structure 21 is attached to the inner wall of the semicircular opening 111, the lateral supporting structure 31 is supported between the top supporting structure 21 and the ground 40, the lateral supporting structure 31 is attached to the inner wall of the rectangular opening 112, and the top supporting structure 21 and the lateral supporting structure 31 are fixedly connected.

[0044] Specifically, the surrounding rock 1 extends with the mountain, and the "+" filled range in the figure is only schematic and does not represent the actual range of the surrounding rock 1. The "-" filled range in the figure represents the range of the semicircular hole 111, and the diagonal line filled range in the figure represents the range of the rectangular hole 112. The top supporting structure 21 is used to resist the earth pressure generated by the top surrounding rock 1, and the two ends of the top supporting structure 21 are respectively connected and fixed with the lateral supporting structure 31, so as to conduct the earth pressure to the ground 40, and form a stable force transmission path. The lateral supporting structure 31 not only bears the load transmitted by the top supporting structure 21, but also bears the lateral earth pressure generated by the bottom soil of the surrounding rock 1. In the construction process of the primary support structure 5, the semicircular hole 111 can be excavated first, then the top supporting structure 21 is erected, then the rectangular hole 112 is excavated, and finally the lateral supporting structure 31 is erected, and the primary support structure 5 and the lateral supporting structure 31 are connected and fixed. This way of segmentally and alternately excavating and supporting from top to bottom can effectively avoid the collapse of the hole caused by one-time excavation, and the original soil at the rectangular hole 112 part can temporarily support the top supporting structure 21. In the related art, the circular arch curved wall structure 20 needs to match an integral circular arc construction hole, so that the primary support also needs to be changed to a circular arch shape, at this time, the midpoint of the bottom surface of the supporting structure and the center of gravity are eccentric, which is not conducive to the stability of the supporting structure. Compared with the circular arch construction hole 11 in the related art, changing the part below the arch line of the construction hole 11 to the rectangular hole 112 can not only greatly reduce the excavation difficulty, but also change the lateral supporting structure 31 to a vertical structure that is easier and more convenient to install and has more stable supporting effect, thereby enhancing the safety and reliability of the primary support structure 5.

[0045] Reference Figure 5 , Figure 6 Optionally, the material of the top supporting structure 21 and the lateral supporting structure 31 is steel profile, and a connecting plate 53 is arranged at the connecting position of the top supporting structure 21 and the lateral supporting structure 31.

[0046] Specifically, the steel profile has good cold bending performance and high bearing capacity, and the top supporting structure 21 adopts steel profile, which is convenient for bending and processing to match the circular arch top wall of the semicircular hole 111. The lateral supporting structure 31 also uses steel profile with the same specifications as the top supporting structure 21, which can facilitate unified procurement, and then according to the design requirements, the raw materials are cut and processed into the required shape and length. In addition, the same material and specifications can facilitate the connection and fixation of the top supporting structure 21 and the lateral supporting structure 31, so that the primary support structure 5 has stronger integrity.

[0047] Since the steel section needs to maintain the structural characteristics of light weight and high strength, the cross-sectional area is usually small, which is inconvenient for butt joint. The connecting plate 53 is arranged at the connecting position of the top support structure 21 and the lateral support structure 31, which can increase the contact area of the connecting position and improve the flatness, and can reduce the construction difficulty whether welding or bolt 533 fixation is adopted.

[0048] In the embodiment, the steel section is preferably an I-beam, and in other embodiments, it can also be an H-beam or a U-beam; the connecting plate 53 is a rectangular plate, and the I-beam is centrally aligned and welded with the connecting plate 53 to ensure that the cross-sectional projection of the I-beam falls completely within the range of the connecting plate 53. In order to clearly show the structure of the connecting plate 53, Figure 6 The filling pattern of the construction opening 11 is removed.

[0049] Referring to Figure 6 Optionally, the connecting plate 53 includes a first plate body 531 and a second plate body 532, the first plate body 531 is welded and fixed with the top support structure 21, the second plate body 532 is welded and fixed with the lateral support structure 31, and the first plate body 531 and the second plate body 532 are fixed by a bolt 533.

[0050] Specifically, the first plate body 531 and the second plate body 532 are welded and fixed with the top support structure 21 and the lateral support structure 31 respectively in advance during factory processing, and a hole for mounting the bolt 533 is formed on the first plate body 531 and the second plate body 532, and then the bolt 533 is used for fixation during on-site assembly, which can avoid the inconvenience of in-situ welding at the connecting position. The pre-fabricated steel section and the connecting plate 53 are connected by the bolt 533, which can greatly improve the construction speed of the primary support structure 5, thereby quickly and effectively supporting the construction opening 11 to prevent the opening from collapsing.

[0051] In the embodiment, the first plate body 531 and the second plate body 532 are made of steel plates of the same grade as the I-beam, and the top support structure 21 and the first plate body 531, and the lateral support structure 31 and the second plate body 532 are circumferentially continuously welded. The first plate body 531 and the second plate body 532 are each provided with a bolt 533 near the four corners, thereby ensuring stable connection and uniform stress between the first plate body 531 and the second plate body 532. In addition, if the top support structure 21 is formed by splicing multiple arc-shaped I-beams, the connecting plate 53 can also be used for connecting and fixing the arc-shaped I-beams. The bottom end of the lateral support structure 31 is also welded with a single-layer connecting plate 54 without a bolt 533 hole. Since the bottom end of the lateral support structure 31 is the most unfavorable position with the largest stress, the single-layer connecting plate 54 can increase the contact area between the I-beam section and the ground 40, thereby dispersing the stress and improving the overall stability of the primary support structure 5.

[0052] With reference to Figure 5 , Figure 6 Optionally, the primary support structure 5 is a multi-arch structure, the top support structure 21 and the lateral support structure 31 on both sides jointly form an arch 51, and a tie 52 is arranged between adjacent arches 51.

[0053] Specifically, the multi-arch structure extends along the length direction of the tunnel, the spacing between adjacent arches 51 is equal, and the full length of the construction opening 11 can be effectively supported uniformly. The tie 52 fixedly connects the two adjacent arches 51, thereby improving the overall stability of the primary support structure 5.

[0054] In this embodiment, the tie 52 is a connecting steel bar with a diameter of 22 mm and a spacing of 100 cm, and the two ends of the steel bar are respectively welded and fixed with the I-shaped steel profile.

[0055] With reference to Figure 5 , Figure 7 Optionally, the bottom end of the top support structure 21 and / or the bottom end of the lateral support structure 31 is provided with an anchoring device 6, and the anchoring device 6 is used to fixedly connect the primary support structure 5 and the surrounding rock 1.

[0056] Specifically, the connecting position of the top support structure 21 and the lateral support structure 31 and the position of the bottom end of the lateral support structure 31 abutting against the ground 40 are key positions affecting the overall stability of the primary support structure 5. Therefore, the anchoring structure is arranged at the key position to be connected and fixed with the surrounding rock 1, which can be supported by the surrounding rock 1 soil body, improve the connection strength of the key position, thereby preventing the primary support structure 5 from collapsing.

[0057] In this embodiment, the bottom end of the top support structure 21 and the bottom end of the lateral support structure 31 are both provided with anchoring devices 6, and the anchoring device 6 is preferably an anchor rod. One anchor rod is arranged adjacent to each side of the I-shaped steel, and the two anchor rods are welded and fixed at the end close to the I-shaped steel by using a steel bar, so that the two anchor rods embrace the I-shaped steel.

[0058] With reference to Figure 8 Optionally, the top arch 2 further comprises a circular arch lining structure 22, and the bottom wall 3 further comprises an arch foot lining structure 32, the circular arch lining structure 22 and the arch foot lining structure 32 jointly form a secondary lining structure 7, the secondary lining structure 7 is arranged on the inner side of the primary support structure 5, the enlarged arch foot 322 is located at the bottom end of the arch foot lining structure 32, and the circular arch lining structure 22 and the arch foot lining structure 32 are integrally formed to make the top arch 2 and the curved surface 321 coaxial.

[0059] Specifically, after the primary support structure 5 is completed, the secondary lining structure 7 needs to be poured inside the primary support structure 5, so as to complete the construction of the main body 10 of the tunnel without the inverted arch. The secondary lining structure 7 is divided into the circular arch lining structure 22 and the arch foot lining structure 32 according to the location. The cross-sectional thickness of the circular arch lining structure 22 is fixed, and the cross-sectional width of the arch foot lining structure 32 gradually increases from top to bottom, so as to form the expanded arch foot 322. The top of the arch foot lining structure 32 has the same thickness as the circular arch lining structure 22, and the arc-shaped inner surface of the arch foot lining structure 32 is tangent to the circular arch lining structure 22. During the construction process, the cast-in-place formwork is arranged inside the tunnel, so that the circular arch lining structure 22 and the arch foot lining structure 32 are integrally poured and formed. The secondary lining structure 7 with the above structure can facilitate the use of the whole circular arch formwork during the construction pouring, improve the pouring quality, and overcome the problem that the pouring quality at the connection is poor due to the need to replace the formwork for the upper and lower parts of the circular arch straight wall structure 30 in the related art.

[0060] Optionally, a deformation joint is arranged between the primary support structure 5 and the secondary lining structure 7.

[0061] Specifically, after the tunnel structure is completed, the surrounding rock 1 will slowly settle, so a deformation joint is reserved during the construction stage. The primary support structure 5 mentioned above is arranged on the inner wall of the construction opening 11, and the secondary lining structure 7 is arranged on the inner side of the primary support structure 5. The above-mentioned arrangement refers to the state of being finally arranged in a matched manner after slow settlement and deformation.

[0062] In this embodiment, the primary support structure 5 built by the I-shaped steel frame and the secondary lining structure 7 are reserved with a deformation allowance of 2cm to 5cm during the construction, and a waterproof board and a geotextile are arranged at the position of the deformation joint to improve the anti-seepage performance.

[0063] Referring to Figure 8 , Figure 9 Optionally, the secondary lining structure 7 includes a steel reinforcement cage 71 and a masonry layer 72, the steel reinforcement cage 71 is glued and fixed in the masonry layer 72, the steel reinforcement cage 71 includes an inner longitudinal reinforcement 711, an outer longitudinal reinforcement 713 and a construction reinforcement 715, the inner longitudinal reinforcement 711 and the outer longitudinal reinforcement 713 are respectively located on both sides of the thickness direction of the masonry layer 72, and the construction reinforcement 715 is used to connect the inner longitudinal reinforcement 711 and the outer longitudinal reinforcement 713. The inner longitudinal reinforcement 711 and the outer longitudinal reinforcement 713 are curved and shaped along the outer contour of the cross section of the masonry layer 72.

[0064] The end of the inner longitudinal rib 711 is bent to form a first bent portion 712 at the enlarged arch foot 322, the end of the outer longitudinal rib 713 is bent to form a second bent portion 714 at the enlarged arch foot 322, the first bent portion 712 and the second bent portion 714 embrace each other, the second bent portion 714 further comprises an embracing segment 7141 perpendicular to the outer longitudinal rib 713 and a complementary segment 7142 parallel to the outer longitudinal rib 713, and the end of the complementary segment 7142 away from the embracing segment 7141 abuts against the inner longitudinal rib 711, so that the complementary segment 7142 compensates the longitudinal rib reinforcement ratio at the position of the enlarged arch foot 322.

[0065] Specifically, the reinforcement cage 71 is a mirror image structure with the tunnel center line as the axis, for clearly showing the internal structure of the reinforcement cage 71, Figure 8 The left side of the tunnel center line is used to show the inner longitudinal rib 711, and the right side is used to show the outer longitudinal rib; Figure 9 The figure shows the complete structure of the reinforcement cage 71. According to the construction sequence, the secondary lining structure 7 is divided into the reinforcement cage 71 and the lining layer 72. During construction, the reinforcement is first tied, the inner longitudinal rib 711 and the outer longitudinal rib 713 are connected and fixed by using the structural rib 715, and the reinforcement cage 71 is tied into an integral whole, then the reinforcement cage 71 is placed at the position of the secondary lining structure 7, and then the formwork is erected and the lining layer 72 is cast in place. Since the cross section of the arch foot lining structure 32 gradually thickens from top to bottom, the traditional method of embracing the ends of the inner longitudinal rib 711 and the outer longitudinal rib 713 will result in insufficient longitudinal rib reinforcement ratio at the position of the enlarged arch foot 322. The inner longitudinal rib 711 and the outer longitudinal rib 713 need to be bent according to the contour shape of the inner side and the outer side of the cross section of the secondary lining structure 7, and the ends of the inner longitudinal rib 711 and the outer longitudinal rib 713 are bent and embraced. Therefore, when tying the reinforcement cage 71, the length required for the complementary segment 7142 at the bottom end of the outer longitudinal rib 713 is reserved, the complementary segment 7142 is parallel to the outer longitudinal rib 713 and the top end is welded and fixed with the inner longitudinal rib 711, so as to compensate the longitudinal rib reinforcement ratio at the position of the enlarged arch foot 322.

[0066] In the embodiment, the length of the embracing segment 7141 of the second bent portion 714 is equal to half of the length of the first bent portion 712, so that the complementary segment 7142 can be centrally arranged, thereby making the longitudinal rib distribution more uniform.

[0067] On the other hand, the utility model provides a tunnel without inverted arch, which comprises the structure without inverted arch.

[0068] Referring to Figure 4 The tunnel without inverted arch further comprises a road surface structure layer 8 and a ditch 9, the road surface structure layer 8 is located below the tunnel portal 4, and the ditch 9 is arranged between the road surface structure layer 8 and the enlarged arch foot 322.

[0069] Specifically, the no-arching structure is the main force structure of the tunnel, and in addition, the no-arching structure further includes a pavement structure layer 8, a ditch 9 and other non-force components.

[0070] In this embodiment, the pavement structure layer 8 is centrally arranged at the bottom center of the tunnel portal 4, and the pavement structure layer 8 is provided with the ditch 9 on both sides, one side being a drainage ditch 91 and the other side being a cable trench 92.

[0071] The no-arching tunnel of this embodiment has the same beneficial effects as the no-arching structure of the prior art, which will not be repeated here.

[0072] Although the utility model discloses as above, the protection scope of the utility model is not limited to this only. The person skilled in the art can make various changes and modifications without departing from the spirit and scope of the utility model, and these changes and modifications will all fall within the protection scope of the utility model.

Claims

1. A no- invert structure, characterized in that, The application relates to a tunnel construction structure, which comprises surrounding rock (1), a top arch (2) and a bottom wall (3), a construction hole (11) is formed in the surrounding rock (1), the top arch (2) and the bottom wall (3) are attached to the inner wall of the construction hole (11), the bottom wall (3) is supported between the top arch (2) and the ground (40), the top arch (2), the bottom wall (3) and the ground (40) jointly form a tunnel hole (4), the side wall of the bottom wall (3) facing the surrounding rock (1) is a vertical straight surface, the side wall of the bottom wall (3) away from the surrounding rock (1) is an arc surface (321), the arc surface (321) is flush with the edge of the top arch (2) and shares a circle with the top arch (2), and the end of the bottom wall (3) close to the ground (40) is provided with an enlarged arch foot (322), the width of the enlarged arch foot (322) is greater than the thickness of the top arch (2).

2. The no-crest structure according to claim 1, wherein The construction hole (11) is composed of a semicircular hole (111) at the upper portion and a rectangular hole (112) at the lower portion, the top arch (2) comprises a top supporting structure (21), the bottom wall (3) comprises a lateral supporting structure (31), the top supporting structure (21) and the lateral supporting structure (31) jointly form an initial supporting structure (5), the top supporting structure (21) is attached to the inner wall of the semicircular hole (111), the lateral supporting structure (31) is supported between the top supporting structure (21) and the ground (40), the lateral supporting structure (31) is attached to the inner wall of the rectangular hole (112), and the top supporting structure (21) and the lateral supporting structure (31) are fixedly connected.

3. The no-crest structure according to claim 2, wherein The initial supporting structure (5) comprises a plurality of arches (51), the top supporting structure (21) and the lateral supporting structures (31) connected to the two sides jointly form an arch (51), and a connecting piece (52) is arranged between adjacent arches (51).

4. The no-crest structure according to claim 3, wherein The material of the top supporting structure (21) and the lateral supporting structure (31) is steel profile, and a connecting plate (53) is arranged at the connecting position of the top supporting structure (21) and the lateral supporting structure (31).

5. The no-arch structure according to claim 4, wherein, The connecting plate (53) comprises a first plate body (531) and a second plate body (532), the first plate body (531) is fixedly welded to the top supporting structure (21), the second plate body (532) is fixedly welded to the lateral supporting structure (31), and the first plate body (531) and the second plate body (532) are fixed by bolts.

6. The no-crest structure according to claim 2, wherein An anchoring device (6) is arranged at the bottom end of the top supporting structure (21) and / or the bottom end of the lateral supporting structure (31), and the anchoring device (6) is used for fixedly connecting the initial supporting structure (5) and the surrounding rock (1).

7. The no-crest structure according to claim 2, wherein The top arch (2) further comprises a round arch lining structure (22), and the bottom wall (3) further comprises an arch foot lining structure (32), the round arch lining structure (22) and the arch foot lining structure (32) jointly constitute a secondary lining structure (7), the secondary lining structure (7) is arranged in the inside of the primary support structure (5), the bottom end of the arch foot lining structure (32) forms the enlarged arch foot (322), and the round arch lining structure (22) and the arch foot lining structure (32) are integrally formed so that the top arch (2) is concentric with the arc surface (321).

8. The no-crest structure according to claim 7, wherein The secondary lining structure (7) comprises a reinforcing cage (71) and a masonry layer (72), the reinforcing cage (71) is glued and fixed in the masonry layer (72), the reinforcing cage (71) comprises an inside longitudinal reinforcement (711), an outside longitudinal reinforcement (713) and a constructional reinforcement (715), the inside longitudinal reinforcement (711) and the outside longitudinal reinforcement (713) are respectively located on both sides of the thickness direction of the masonry layer (72), the constructional reinforcement (715) is used for connecting the inside longitudinal reinforcement (711) and the outside longitudinal reinforcement (713), and the inside longitudinal reinforcement (711) and the outside longitudinal reinforcement (713) are curved and shaped along the cross section outer contour of the masonry layer (72); The end of the inside longitudinal reinforcement (711) is bent to form a first bending part (712) at the enlarged arch foot (322), the end of the outside longitudinal reinforcement (713) is bent to form a second bending part (714) at the enlarged arch foot (322), the first bending part (712) and the second bending part (714) are mutually embraced, the second bending part (714) comprises a clamping segment (7141) perpendicular to the outside longitudinal reinforcement (713) and a supplementary segment (7142) parallel to the outside longitudinal reinforcement (713), and one end of the supplementary segment (7142) away from the clamping segment (7141) is abutted against the inside longitudinal reinforcement (711); and the supplementary segment (7142) is used for making up the longitudinal reinforcement ratio at the position of the enlarged arch foot (322).

9. The no-crest structure according to claim 7, wherein A deformation joint is arranged between the primary support structure (5) and the secondary lining structure (7).

10. A tunnel without invert, characterized in that, The no-arch structure comprises the no-arch structure according to any one of claims 1-9, further comprising a road surface structure layer (8) and a ditch (9), the road surface structure layer (8) is located below the tunnel portal (4), and the ditch (9) is arranged between the road surface structure layer (8) and the enlarged arch foot (322).

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