Construction method of fishbone-shaped ultra-large underground space supporting system and supporting system

Abstract

The invention discloses a construction method of a fishbone-shaped ultra-large underground space supporting system and the supporting system.The method comprises the following steps that S1, a pilot tunnel is excavated, and primary supporting is conducted on the pilot tunnel; s2, a rib arch space and a foundation structure space are excavated from the side wall of the pilot tunnel, then a foundation structure and a rib arch are manufactured, and the foundation structure, the rib arch and the pilot tunnel form a whole; and S3, after the pilot tunnel, the foundation structure and the rib arch are maintained to be qualified, the underground space below the pilot tunnel and the rib arch is excavated. The invention discloses a construction method using a fishbone-shaped super-large underground space supporting system. The method has the beneficial effects that the pilot tunnel is excavated firstly, then the rib arch and the foundation structure are excavated from the side wall of the pilot tunnel and manufactured, and after the foundation structure, the rib arch and the pilot tunnel reach the design strength, the underground space located below the fishbone-shaped top support is excavated, so that the fishbone-shaped support system bears the pressure of the top surrounding rock; use of a large number of temporary supports can be reduced, and the construction difficulty of underground engineering is lowered.

Description

Technical Field

[0001] The present invention relates to the field of engineering, and in particular to a construction method and a support system of a fishbone-shaped ultra-large underground space support system. Background Art

[0002] With the development and utilization of underground space, in order to meet the needs of economic development, there are more and more tunnels and underground projects with super-large cross-sections and super-large spans.

[0003] At present, traditional super-large underground projects are constructed in a divided and zoned manner, which requires a lot of temporary supports. In addition, the top surrounding rock is greatly disturbed during the construction of traditional underground projects, and the top surrounding rock may undergo significant deformation, resulting in certain safety hazards in the construction process of underground projects. Summary of the invention

[0004] The technical problem to be solved by the present invention is that the current traditional underground engineering construction causes great disturbance to the top surrounding rock, and the top surrounding rock may undergo great deformation. The purpose is to provide a construction method and support system for a fishbone-shaped ultra-large underground space support system. Before the underground engineering is excavated, a complete continuous fishbone-shaped support system is formed in advance on the top of the underground engineering to be constructed, so as to prevent the top surrounding rock of the underground engineering from undergoing great deformation during construction.

[0005] The present invention is achieved through the following technical solutions:

[0006] A construction method for a fishbone-shaped ultra-large underground space support system comprises the following steps: S1, excavating a pilot tunnel and providing initial support to the pilot tunnel; S2, excavating a rib arch space and a foundation structure space from the side wall of the pilot tunnel, and then making a foundation structure and a rib arch, wherein the foundation structure, the rib arch and the pilot tunnel form a whole; S3, after the pilot tunnel, the foundation structure and the rib arch are maintained to a qualified standard, excavating the underground space below the pilot tunnel and the rib arch.

[0007] The beneficial effect of the present invention is that, by first excavating a pilot tunnel and performing initial support treatment on the pilot tunnel to ensure that the pilot tunnel has a certain strength, then excavating several rib arch spaces and foundation structure spaces along the radial direction of the pilot tunnel from the side wall of the pilot tunnel, and then making rib arches and foundation structures in the rib arch spaces and foundation structure spaces, after the foundation structure, rib arches and pilot tunnels reach the designed strength, the underground space below the fishbone-shaped top support is excavated, so that the arch has formed a complete continuous support system when the underground project is excavated, and the fishbone-shaped support system bears the top surrounding rock pressure. At this time, the excavation has minimal disturbance to the surrounding rock, which can reduce the use of a large number of temporary supports and reduce the construction difficulty of the underground project. The pilot tunnel can be used for advanced geological prediction, and the arrangement spacing of the rib arches along the axis, the arrangement length and spacing of the anchor cables and anchor rods can be adjusted in real time according to the explored surrounding rock conditions, so as to bear the top surrounding rock pressure with a more accurate structural system.

[0008] In some embodiments, after the full length of the pilot tunnel is completed or the pilot tunnel is advanced by a certain distance to the underground space that has not been made, longitudinal reinforced concrete is made at the bottom of the pilot tunnel, and side wall reinforced concrete is made in the areas connected to the rib arches on both sides of the pilot tunnel. When making the rib arches, a section of steel bars is reserved so that the longitudinal reinforced concrete and the side wall reinforced concrete form a whole. By making longitudinal reinforced concrete at the bottom of the pilot tunnel, it is convenient to improve the overall stability of the fishbone-shaped vault support system, and when making the rib arches, steel bars are reserved so that the longitudinal reinforced concrete and the side wall reinforced concrete form a whole, so that the pilot tunnel and the rib arches form a whole, thereby improving the strength, rigidity and stability of the vault of the underground project.

[0009] In some embodiments, when executing step S2, a tie beam space is excavated on the side wall of the rib arch space, the tie beam space is excavated along the radial direction of the rib arch space, the tie beam and the rib arch are cast synchronously, and the tie beam and several rib arches in the same row are cast as a whole. By excavating the tie beam space synchronously when excavating the rib arch space, it is convenient to cast the tie beam and several rib arches in the same row as a whole during casting, thereby further improving the strength, rigidity and stability of the herringbone vault support system.

[0010] In some embodiments, the pilot tunnel can be excavated in sections, and after a section of the pilot tunnel is excavated and initially supported, the rib arches connected to the section of the pilot tunnel can be manufactured after the initial support and maintenance are qualified. Excavating the pilot tunnel in sections facilitates ensuring the safety of the construction.

[0011] In some embodiments, several ribs are fabricated at intervals, and the remaining ribs are fabricated after the fabricated rib structures reach the designed strength. The ribs are constructed at intervals to further ensure construction safety and prevent disturbances between sections due to excavation of rib sections that are too close during construction.

[0012] In some embodiments, when executing step S3, after the underground space is excavated to the set depth, several retaining plates between ribs are made, and the retaining plates between ribs are connected to the corresponding ribs, and the corresponding ribs in the same row are connected into a closed whole, and the retaining plates between ribs form the top of the underground space. By setting the retaining plates between ribs, the continuity of the fishbone support system is improved, its shear strength is enhanced, and the bearing capacity of the fishbone support system itself is fully utilized. The retaining plates between ribs can be used as the top of the underground project.

[0013] In some embodiments, the foundation structure includes an inclined pile foundation and a horizontal foundation, wherein the inclined pile foundation is connected to the end of the rib arch away from the guide hole, and the horizontal foundation is connected to both ends of the rib arch, and the corresponding rib arch is supported axially by the foundation structure. By setting the foundation structure, the rib arch is supported and positioned axially, and the axial load of the rib arch is transferred to the surrounding rock, thereby ensuring the stability of the herringbone support system.

[0014] In some embodiments, the underground space is excavated in layers, and the underground space includes an upper step and a lower step. The upper step is excavated in a graded manner and an anchor frame beam is set on the side wall of the upper step. The lower step is supported by a pile-sheet wall, and the underground space excavation plan is converted into a foundation pit excavation plan. It is convenient to convert the passive and real-time support of traditional underground engineering into active and advance support, and to convert the construction plan of super-large section and super-large span tunnels and underground engineering into a foundation pit-like construction plan after pre-construction of small structures and forming a fishbone support system, which simplifies the complex and makes it easy, and can reduce the use of a large number of temporary supports.

[0015] The present invention also provides a fishbone-shaped ultra-large underground space support system, including a guide tunnel, a plurality of rib arches, and a plurality of retaining plates between the rib arches. The guide tunnel is provided with at least one, and the top of the guide tunnel is located in the surrounding rock; the rib arches are provided with a set distance, the rib arches are connected to the side wall of the guide tunnel, the rib arches are cast and formed after radial excavation along the guide tunnel, and the rib arches and the guide tunnel are both located at the top of the underground space; the retaining plates between the rib arches are used to connect the rib arches in the same row together. By providing a guide tunnel and casting and forming the rib arches after radial excavation along the guide tunnel, the disturbance to the surrounding rock is reduced, and the guide tunnel and the rib arches are connected together to form a whole, so as to form a vault support together before the underground engineering excavation is carried out, and prevent the top surrounding rock from being greatly deformed during construction.

[0016] In some embodiments, it also includes a pile-sheet wall and an anchor frame beam, the top of the anchor frame beam is in contact with the retaining plate between the rib arches, the pile-sheet wall is located at the lower end of the anchor frame beam, and the underground space is the space formed by the pile-sheet wall, the anchor frame beam and the fishbone support system, and the underground space excavation plan is converted into a foundation pit excavation plan. It is convenient to convert the passive and real-time support of traditional underground engineering into active and advance support, and convert the construction plan of super-large section and super-large span tunnels and underground engineering into a foundation pit-like construction plan after pre-construction of small structures and formation of a fishbone support system, which simplifies the complex and makes it easy, and can reduce the use of a large number of temporary supports.

[0017] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0018] 1. First, excavate the pilot tunnel and perform initial support treatment on the pilot tunnel to ensure that the pilot tunnel has a certain strength. Then, excavate several rib arch spaces and foundation structure spaces along the radial direction of the pilot tunnel starting from the side wall of the pilot tunnel. Then, make rib arches and foundation structures in the rib arch spaces and foundation structure spaces. After the foundation structure, rib arches and pilot tunnel reach the designed strength, excavate the underground space under the fishbone-shaped top support. When the underground project is excavated, the arch has formed a complete continuous support system. The fishbone-shaped support system bears the top surrounding rock pressure. At this time, the excavation has minimal disturbance to the surrounding rock, which can reduce the use of a large number of temporary supports and reduce the construction difficulty of the underground project.

[0019] 2. Setting up a fishbone support system in advance can facilitate the transformation of the passive, real-time support of traditional underground projects into active, advance support, and transform the construction plan of ultra-large section and ultra-large span tunnels and underground projects into a foundation pit-like construction plan after the pre-construction of small structures and the formation of a fishbone support system, thus simplifying the complex and making the difficult easier, and reducing the use of a large number of temporary supports.

[0020] 3. Constructing the rib arches at intervals can further ensure construction safety and prevent disturbance between sections due to excavation of rib arch sections that are too close during construction.

[0021] 4. The pilot tunnel can be used for advanced geological prediction. According to the explored surrounding rock conditions, the spacing of the rib arches along the axis, the length and spacing of the anchor cables and anchor rods can be adjusted in real time to bear the top surrounding rock pressure with a more accurate structural system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0023] Figure 1 It is a front view of a single guide hole in the present invention;

[0024] Figure 2 It is a front view of two single guide holes connected in the present invention;

[0025] Figure 3 It is the front view of the double guide hole in the present invention;

[0026] Figure 4 It is a partial structural diagram of a single guide hole in the present invention;

[0027] Figure 5 It is a partial structural diagram of the double guide hole in the present invention;

[0028] Figure 6 It is a structural diagram of a single guide hole in the present invention.

[0029] Marks and corresponding parts names in the attached drawings:

[0030] Guide tunnel 10, longitudinal reinforced concrete 11, rib arch 20, anchoring structure 21, inclined pile foundation 22, retaining plate 23 between rib arches, pile-sheet wall 31, anchor cable frame beam 32, tie beam 40, middle pile foundation 42. DETAILED DESCRIPTION

[0031] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0032] Throughout the specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment," "an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily all refer to the same embodiment or example. In addition, particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. In addition, it will be appreciated by those of ordinary skill in the art that the figures provided herein are for illustrative purposes and that the figures are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0033] In the description of the present invention, the directions or positional relationships indicated by terms such as “front”, “rear”, “left”, “right”, “up”, “down”, “vertical”, “horizontal”, “high”, “low”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the scope of protection of the present invention.

[0034] The terms "first" and "second" used in the present invention are only used to distinguish the corresponding components for the sake of clarity of description, and are not intended to limit any order or emphasize importance, etc. In addition, the term "connected" used in this article can be directly connected or indirectly connected via other components without special explanation.

[0035] Example 1

[0036] Provide a construction method for a fishbone-shaped ultra-large underground space support system, see Figure 1-Figure 6, including the following steps: S1, excavating a guide tunnel 10 and providing initial support for the guide tunnel 10; S2, excavating a rib arch 20 space and a foundation structure space from the side wall of the guide tunnel 10, and then making a foundation structure and the rib arch 20, wherein the foundation structure, the rib arch 20 and the guide tunnel 10 form a whole; S3, after the guide tunnel 10, the foundation structure and the rib arch 20 are maintained to a qualified standard, excavating the underground space below the guide tunnel 10 and the rib arch 20. By first excavating the pilot tunnel 10 and performing initial support treatment on the pilot tunnel 10 to ensure that the pilot tunnel 10 has a certain strength, then starting from the side wall of the pilot tunnel 10 along the radial direction of the pilot tunnel 10, several rib arch 20 spaces and foundation structure spaces are excavated, and then the rib arch 20 and foundation structure are made in the rib arch 20 space and foundation structure space. After the foundation structure, rib arch 20 and pilot tunnel 10 reach the design strength, the underground space below the fishbone top support is excavated, so that the arch has formed a complete continuous support system when the underground project is excavated, and the fishbone support system bears the top surrounding rock pressure. At this time, the excavation has minimal disturbance to the surrounding rock, which can reduce the use of a large number of temporary supports and reduce the construction difficulty of the underground project. The pilot tunnel 10 can be used for advanced geological prediction, and the arrangement spacing of the rib arch 20 along the axis, the arrangement length and spacing of the anchor cable and anchor rod can be adjusted in real time according to the explored surrounding rock conditions, so as to bear the top surrounding rock pressure with a more accurate structural system. The fishbone rib arch 20 structure formed at the top of the underground space by this method is independent of the lower space. The fishbone support system occupies the space required for support, and the bottom is the underground space required for functionality, with a high degree of free combination and strong adaptability.

[0037] See also Figure 1-Figure 6 After the full length of the guide tunnel 10 is completed or the guide tunnel is advanced to a certain distance of the underground space that has not been made in advance (the guide tunnel is excavated in sections), a longitudinal reinforced concrete 11 is made at the bottom of the guide tunnel 10, and side wall reinforced concrete is made in the areas connected to the rib arches 20 on both sides of the guide tunnel 10. When making the rib arches 20, a section of steel bars is reserved to make the longitudinal reinforced concrete 11 and the side wall reinforced concrete form a whole. By making the longitudinal reinforced concrete 11 at the bottom of the guide tunnel 10, it is convenient to improve the overall stability of the fishbone-shaped vault support system. When making the rib arches 20, a section of steel bars is reserved to make the longitudinal reinforced concrete 11 and the side wall reinforced concrete form a whole, so that the guide tunnel 10 and the rib arches 20 form a whole, thereby improving the strength, rigidity and stability of the vault of the underground project. The longitudinal reinforced concrete 11 can adopt a solid or hollow structure, and the type of use can be selected on the premise of meeting the design strength.

[0038] See also Figure 5When executing step S2, a space for the tie beam 40 is excavated on the side wall of the space of the rib arch 20, the space for the tie beam 40 is excavated along the radial direction of the rib arch 20, the tie beam 40 is cast synchronously with the rib arch 20, and the tie beam 40 and the rib arches 20 in the same row are cast as a whole. By excavating the space for the tie beam 40 when excavating the space for the rib arch 20, it is convenient to cast the tie beam 40 and the rib arches 20 in the same row as a whole during casting, thereby further improving the strength, rigidity and stability of the herringbone vault support system.

[0039] See also Figure 1-Figure 6 The guide tunnel 10 can be excavated in sections. After a section of the guide tunnel 10 is excavated and initially supported, the rib arch 20 connected to the section of the guide tunnel 10 can be manufactured after the initial support and maintenance are qualified. Excavating the guide tunnel 10 in sections is convenient for ensuring the safety of construction.

[0040] See also Figure 1-Figure 6 , several of the ribs 20 are manufactured at intervals, and when the manufactured ribs 20 structure reaches the designed strength, the remaining ribs 20 are manufactured. The ribs 20 are constructed at intervals to further ensure construction safety and prevent disturbance between sections due to excavation of ribs 20 sections that are too close during construction.

[0041] See also Figure 1-Figure 6 When executing step S3, after the underground space is excavated to the set depth, several rib-arch retaining plates 23 are made. The rib-arch retaining plates 23 are connected to the corresponding rib arches 20, and the corresponding rib arches 20 in the same row are connected into a closed whole. The rib-arch retaining plates 23 form the top of the underground space. By setting the rib-arch retaining plates 23, the continuity of the herringbone support system is improved, its shear strength is enhanced, and the bearing capacity of the herringbone support system itself is fully utilized. The rib-arch retaining plates 23 can be used as the top of the underground project.

[0042] See also Figure 1-Figure 6 The foundation structure includes an inclined pile foundation 22 and a horizontal foundation. The inclined pile foundation 22 is connected to the end of the rib arch 20 away from the guide tunnel 10, and the horizontal foundation is connected to both ends of the rib arch 20. The corresponding rib arch 20 is supported axially by the foundation structure. By setting the foundation structure, the rib arch 20 is supported and positioned axially, and the axial load of the rib arch 20 is transferred to the surrounding rock to ensure the stability of the herringbone support system. The horizontal foundation and the inclined pile foundation 22 are both located outside the underground space, providing support for the rib arch 20 and ensuring the strength and rigidity of the underground space.

[0043] See also Figure 1-Figure 6The underground space is excavated in layers. The underground space includes an upper step and a lower step. The upper step is excavated in a graded manner and an anchor frame beam 32 is provided on the side wall of the upper step. The lower step is supported by a pile board wall 31. The underground space excavation plan is converted into a foundation pit excavation plan. It is convenient to convert the passive and real-time support of traditional underground engineering into active and advance support, and to convert the construction plan of super-large section and super-large span tunnels and underground engineering into a foundation pit-like construction plan after pre-construction of small structures and forming a fishbone support system. It simplifies the complex and makes it easy, and can reduce the use of a large number of temporary supports.

[0044] See also Figure 1 and Figure 6 Taking the excavation of a single guide tunnel 10 fishbone support system structure as an example, first excavate the top guide tunnel 10 tunnel and construct the guide tunnel 10 anchor structure 21 (initial support). The cross-sectional size of the guide tunnel 10 should comprehensively consider the main auxiliary construction functions, the advanced geological guide tunnel 10 functions, and the underground structure ventilation functions (the top guide tunnel 10 can be used as a ventilation level guide for the underground space). Excavate a certain height downward in the guide tunnel 10 tunnel to use as the construction space of the arch structure. Excavate the aforementioned proposed structural sections along the aforementioned proposed arch axis direction on both sides of the guide tunnel 10. During the excavation process, prestressed anchor cables and grouting anchor rods are applied in the radial direction of the arch axis, and inclined piles are applied at the ends of the rib arch 20 structure as a force foundation. After the inclined piles are installed, the rib arch 20 section is subjected to steel cage pouring construction to form a reinforced concrete arch structure. At the same time, to ensure construction safety, the next rib arch 20 structure is constructed at intervals of one rib arch 20. After the strength of the two rib arches 20 reaches a certain proportion of the design strength, the middle rib arch 20 is constructed (for example, the N, N+2, and N+4 rib arches 20 are constructed first, and then the N+1 and N+3 rib arches 20 are constructed). This cycle is repeated. After the rib arch 20 structure with an axial range of 30-60m is constructed, the reinforced concrete in the area between the bottom of the guide tunnel 10 and the rib arches 20 on both sides is constructed axially through, and the rib arches 20 on both sides and the middle reinforced concrete structure form a ring-shaped whole by reserving steel bars. The middle reinforced concrete structure can choose whether to have an opening design according to the stress conditions to save construction costs.

[0045] See also Figure 3 and Figure 5Taking the excavation of the double guide tunnel 10 fishbone support system as an example, the guide tunnels 10 on both sides are excavated and the guide tunnel 10 anchoring structure 21 (initial support) is constructed. The cross-sectional size of the guide tunnel 10 should comprehensively consider the main auxiliary construction functions and the advanced geological guide tunnel 10 functions, the underground structure ventilation function (the guide tunnels 10 on both sides and the underground space can form a full horizontal ventilation system), and the upper space can meet the function of construction vehicles after the foundation structure (expanded foundation) is constructed. The aforementioned structural section is excavated from the guide tunnels 10 on both sides along the aforementioned proposed arch axis to the middle. During the excavation process, prestressed anchor cables and grouting anchor rods are constructed along the radial direction of the arch axis. After the excavation is completed, the section is poured with a steel cage to form a reinforced concrete arch structure. The expanded foundation is constructed at both ends of the rib arch 20 structure, and the expanded foundation should be in good contact with the surrounding rock. Along the axial direction of the guide tunnel 10, according to the calculated spacing of the rib arches 20, and to ensure construction safety, the next rib arch 20 structure is constructed with one rib arch 20 between them. After the strength of the two rib arches 20 reaches a certain proportion of the design strength, the middle rib arch 20 is constructed (e.g., first construct the N, N+2, and N+4 rib arches 20, and then construct the N+1 and N+3 rib arches 20), and this cycle is repeated. To ensure the overall stability of the support structure, while excavating the rib arch 20 structure, a reinforced concrete structure as a tie beam 40 should be synchronously constructed along the axial direction of the guide tunnel 10 at the middle position of the top of the rib arch 20 structure. The cross section of the tie beam 40 can be the same as the cross section of the arch structure. When excavating the arch section, the next cycle of tie beams 40 are constructed along the axial direction (e.g., when constructing the N rib arch 20, the middle tie beam 40 is excavated along the axial direction toward the N+2 rib arch 20, and the N+1 rib arch 20 area is skipped to pour the tie beam 40, and this position is poured when the N+1 rib arch 20 is constructed). In addition, the tie beam 40 can be designed with holes according to the stress conditions to save costs.

[0046] Embodiment 2,

[0047] The present invention also provides a fishbone-shaped ultra-large underground space support system, see Figure 1-Figure 6 , including a guide tunnel 10, several rib arches 20 and several retaining plates 23 between the rib arches, the guide tunnel 10 is provided with at least one, the top of the guide tunnel 10 is located in the surrounding rock; there is a setting distance between the rib arches 20, the rib arches 20 are connected to the side wall of the guide tunnel 10, the rib arches 20 are cast after radial excavation along the guide tunnel 10, the rib arches 20 and the guide tunnel 10 are both located at the top of the underground space, and the rib arches 20 are located in the surrounding rock; the retaining plates 23 between the rib arches are used to connect the rib arches 20 in the same row together. By setting the guide tunnel 10, and casting the rib arches 20 after radial excavation along the guide tunnel 10, the disturbance to the surrounding rock is reduced, and the guide tunnel 10 and the rib arches 20 are connected together to form a whole, forming the vault of the underground space, which is convenient for forming the vault before the underground engineering excavation, and preventing the top surrounding rock from being greatly deformed during construction.

[0048] See also Figure 1-Figure 6 , and also includes a pile-sheet wall 31 and an anchor frame beam 32. The top of the anchor frame beam 32 is in contact with the retaining plate 23 between the rib arches. The pile-sheet wall 31 is located at the lower end of the anchor frame beam 32. The underground space is the space formed by the pile-sheet wall 31, the anchor frame beam 32 and the fishbone support system. Converting the underground space excavation plan into a foundation pit excavation plan facilitates the conversion of the passive and real-time support of traditional underground engineering into active and advance support, and converting the construction plan of ultra-large section and ultra-large span tunnels and underground engineering into a foundation pit-like construction plan after pre-construction of small structures and formation of a fishbone support system, which simplifies the complex and makes the difficult easy, and can reduce the use of a large number of temporary supports.

[0049] Specifically, see Figure 1 , Figure 4 and Figure 6 It is a herringbone support system structure of a single guide tunnel 10. A row of arc-shaped rib arches 20 are arranged on both sides of the guide tunnel 10. An inclined pile foundation 22 is arranged at the free end of the rib arch 20. The cross-section of the inclined pile foundation 22 gradually increases from the rib arch 20 to the free end of the inclined pile foundation 22, which can transfer and disperse the load and avoid damage to the surrounding rock due to excessive stress.

[0050] Among them, see Figure 2 The two connected single guide tunnels 10 correspond to the fishbone support system structure of two adjacent underground spaces. A middle pile foundation 42 is arranged on the adjacent side of the two single guide tunnels 10. The cross-section of the middle pile foundation 42 is T-shaped. Both sides of the top of the middle pile foundation 42 are provided with a first inclined surface. The side where the rib arch 20 is connected to the middle pile foundation 42 is provided with a second inclined surface matched with the first inclined surface to withstand the axial force of the rib arch 20 and ensure the stability of the fishbone support system.

[0051] Among them, see Figure 3 and Figure 5 The double guide tunnel 10 herringbone support system structure has two guide tunnels 10, which are respectively located on both sides of the rib arch 20, and a tie beam 40 is arranged on the top of the rib arch 20. The longitudinal reinforced concrete 11 located in the guide tunnel 10 constitutes the horizontal expansion foundation of the rib arch 20. The foundation can transfer and disperse the load to avoid damage to the surrounding rock caused by excessive stress.

[0052] See also Figure 1-Figure 6 , and also includes an anchoring structure 21, which is used to make anchor cables and anchor rods (initial support) in the radial direction of the guide tunnel 10 and the rib arch 20 when excavating the space between the guide tunnel 10 and the rib arch 20 to ensure the stability of the guide tunnel 10 and the rib arch 20.

[0053] In actual construction, the above three fishbone support system structures can be selected according to actual needs. When the project investment is low and the construction period is not urgent, a single guide tunnel 10 fishbone support system structure can be selected. When the project investment is high but the construction period is urgent, a double guide tunnel 10 fishbone support system structure can be selected. For example, when constructing a double-hole tunnel, two connected single guide tunnels 10 fishbone support system structures can be selected.

[0054] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A construction method for a fishbone-shaped ultra-large underground space support system, characterized in that: The steps include: S1, excavate the pilot tunnel and provide initial support for the pilot tunnel; S2, excavating a rib arch space and a foundation structure space from the side wall of the pilot tunnel, and then making a foundation structure and a rib arch, wherein the foundation structure, the rib arch and the pilot tunnel form a whole; S3: After the guide tunnel, foundation structure and rib arch have passed the maintenance, the underground space under the guide tunnel and rib arch will be excavated.

2. The construction method of the fishbone-shaped super-large underground space support system according to claim 1 is characterized in that: After the entire length of the guide tunnel is completed or the guide tunnel extends a certain distance beyond the underground space that has not been constructed in advance, longitudinal reinforced concrete is fabricated at the bottom of the guide tunnel, and side wall reinforced concrete is fabricated in the areas connected to the rib arches on both sides of the guide tunnel. When fabricating the rib arches, a section of steel bar is reserved to allow the longitudinal reinforced concrete and the side wall reinforced concrete to form a whole.

3. The construction method of the fishbone-shaped super-large underground space support system according to claim 1 is characterized in that: When executing step S2, a tie beam space is dug on the side wall of the rib arch space, the tie beam space is excavated along the radial direction of the rib arch space, the tie beam is cast synchronously with the rib arch, and the tie beam and several rib arches in the same row are cast as a whole.

4. The construction method of the fishbone-shaped super-large underground space support system according to claim 1 is characterized in that: The guide tunnel can be excavated in sections. After a section of the guide tunnel is excavated and initially supported, the rib arches connected to the section of the guide tunnel can be manufactured after the initial support and maintenance are qualified.

5. The construction method of the fishbone-shaped super-large underground space support system according to claim 1 is characterized in that: Several of the ribs are manufactured at intervals, and the remaining ribs are manufactured after the manufactured rib structure reaches the designed strength.

6. The construction method of the fishbone-shaped super-large underground space support system according to claim 1 is characterized in that: When executing step S3, after the underground space is excavated to the set depth, several retaining plates are made between the rib arches. The retaining plates between the rib arches are connected to the corresponding rib arches, connecting the corresponding rib arches in the same row into a closed whole. The rib arches and the retaining plates between the rib arches form the top of the underground space.

7. The construction method of the fishbone-shaped super-large underground space support system according to claim 1 is characterized in that: The foundation structure includes an inclined pile foundation and a horizontal foundation. The inclined pile foundation is connected to one end of the rib arch away from the guide hole, and the horizontal foundation is connected to both ends of the rib arch. The corresponding rib arch is supported axially by the foundation structure.

8. The construction method of the fishbone-shaped super-large underground space support system according to claim 1 is characterized in that: The underground space is excavated in layers, and the underground space includes an upper step and a lower step. The upper step is excavated with graded slopes and anchor frame beams are set on the side walls of the upper step. The lower step is supported by pile and board walls, converting the underground space excavation plan into a foundation pit excavation plan.

9. A fishbone-shaped ultra-large underground space support system, characterized in that: The construction method using the fishbone-shaped ultra-large underground space support system according to any one of claims 1 to 8 comprises: A guide hole, at least one of which is provided; A plurality of rib arches, wherein a set distance is provided between the rib arches, the rib arches are connected to the side wall of the pilot tunnel, the rib arches are cast after radial excavation along the pilot tunnel, the rib arches and the pilot tunnel are both located at the top of the underground space, and the rib arches are located in the surrounding rock; A plurality of earth retaining plates between rib arches are used to connect the rib arches in the same row together.

10. The fishbone-shaped ultra-large underground space support system according to claim 9, characterized in that: It also includes a pile-board wall and an anchor frame beam, the top of the anchor frame beam is in contact with the retaining plate between the rib arches, the pile-board wall is located at the lower end of the anchor frame beam, and the underground space is the space formed by the pile-board wall, the anchor frame beam and the herringbone support system, which converts the underground space excavation plan into a foundation pit excavation plan.

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