Supporting structure giving consideration to short-term extrusion deformation and long-term rheological deformation of tunnel surrounding rock and construction method

Abstract

The invention discloses a supporting structure giving consideration to short-term extrusion deformation and long-term rheological deformation of tunnel surrounding rock and a construction method, relates to the field of tunnel construction, is particularly suitable for high-ground-stress soft rock stratum.The supporting structure comprises a primary support and a secondary lining, and a yielding concrete layer is arranged between the primary support and the secondary lining; and a plurality of yielding components are arranged in the primary support and the yielding concrete layer. The invention provides a supporting structure giving consideration to short-term extrusion deformation and long-term rheological deformation of tunnel surrounding rocks and a construction method to solve the problem that long-term rheological deformation of the surrounding rocks is difficult to deal with in the tunnel operation process in the prior art and achieve giving consideration to extrusion deformation release of the tunnel surrounding rocks in a short term and long-term rheological deformation in the operation period. And the method is more suitable for the high-crustal-stress soft rock tunnel.

Description

Technical Field

[0001] The present invention relates to the field of tunnel construction, and in particular to a support structure and a construction method that take into account both short-term extrusion deformation and long-term rheological deformation of tunnel surrounding rocks. Background Art

[0002] Large deformation of the weak surrounding rock is a significant engineering challenge for tunnel construction in high-in-situ stress soft rock. Monitoring data from surrounding rock in multiple tunnels shows that the ultimate deformation of the weak surrounding rock under high-in-situ stress conditions can often exceed 30 cm, and in some cases even exceed 1 meter.

[0003] Traditionally, grouting reinforcement measures have been used to control the loosening and deformation of surrounding rock in soft rock tunnels. However, this traditional process has drawbacks such as poor control of grouting effects and significant delays in construction progress. Existing technologies have also introduced some measures to improve and optimize support structures to resist surrounding rock deformation, but these existing technologies have the following drawbacks in high-in-situ stress soft rock conditions:

[0004] During the life cycle of a tunnel, surrounding rock deformation can be divided into "short-term compression deformation" and "long-term rheological deformation" based on the time it takes for surrounding rock to deform. Short-term compression deformation refers to surrounding rock deformation occurring during tunnel excavation and support, while long-term rheological deformation refers to surrounding rock deformation during the tunnel's operation period. During tunnel excavation and support, the process of generating "short-term compression deformation," the ground stress release rate is rapid, the surrounding rock deformation rate and amount are large, and the deformation of the initial support structure also increases. When the initial support structure deformation is excessive, the bearing capacity of the support structure decreases, and it may even fail and lose its bearing capacity. Soft rock under high ground stress conditions typically exhibits rheological properties. That is, the rheological deformation of the surrounding rock gradually increases over time, resulting in increasing surrounding rock pressure on the support structure, leading to frequent problems such as cracking in the support structure at a later stage.

[0005] The support structures in existing technologies generally only consider the resistance to short-term extrusion deformation, which makes it difficult to cope with the long-term rheological deformation of the surrounding rock during operation, and their adaptability to high-stress soft rock tunnels is limited. Summary of the Invention

[0006] The present invention provides a support structure and construction method that take into account both the short-term extrusion deformation and long-term rheological deformation of the tunnel surrounding rock, so as to solve the problem that the existing technology is difficult to cope with the long-term rheological deformation of the surrounding rock during the operation of the tunnel, and achieve the purpose of taking into account both the short-term extrusion deformation release of the tunnel surrounding rock and the long-term rheological deformation during the operation period, which is more suitable for high-stress soft rock tunnels.

[0007] The present invention is achieved through the following technical solutions:

[0008] A support structure that takes into account both short-term extrusion deformation and long-term rheological deformation of tunnel surrounding rock, including initial support and secondary lining, with a yield concrete layer between the initial support and the secondary lining, and a plurality of yield components are arranged in the initial support and the yield concrete layer.

[0009] In response to the problem that the existing technology is difficult to deal with the long-term rheological deformation of the surrounding rock during tunnel operation, the present invention first proposes a support structure that takes into account both the short-term extrusion deformation and long-term rheological deformation of the tunnel surrounding rock. The structure provides a yield concrete layer between the initial support and the secondary lining of the tunnel, and provides yield components inside the yield concrete layer and the initial support.

[0010] When this application is used in practice, the short-term extrusion deformation of the tunnel surrounding rock is mainly resisted by the existing initial support structure. During the operation period of the tunnel, the rheological deformation of the soft rock surrounding rock caused by high ground stress first causes the deformation of the initial support structure, and then causes the compression of the yield concrete layer, that is, the rheological deformation of the surrounding rock is absorbed for the first time by the yield concrete layer. As the operation time of the tunnel continues to increase, the rheological deformation of the surrounding rock continues to increase. When the extrusion deformation of the yield concrete layer is large and the thickness of the yield concrete layer is equal to or less than the thickness of the yield member inside it, the yield member and the yield concrete layer will jointly bear the rheological deformation of the surrounding rock in the later stage.

[0011] This application uses a yielding concrete layer and yielding components located within the yielding concrete layer to fully bear the later rheological deformation of the tunnel surrounding rock under high ground stress soft rock formation conditions, thereby ensuring the stability and effectiveness of the initial support structure during long-term operation and reducing the risk of damage to the initial support structure. In addition, this application also provides a yielding component inside the initial support, which can improve the support resistance of the initial support system and improve the stability of the tunnel. This application also abandons the technical idea of ​​using grouting reinforcement in the existing technology, and overcomes the disadvantages of low controllability of the grouting effect and forced delays in the construction period.

[0012] Therefore, the present application is particularly suitable for controlling deformation of tunnels in high-stress soft rock formations throughout their entire life cycle.

[0013] Furthermore, the yield concrete layer is EPS concrete sprayed on the inner wall of the initial support.

[0014] The EPS concrete used in this solution is a lightweight concrete that uses polystyrene particles to replace part or all of the coarse aggregate in traditional concrete. It has the characteristics of low density and lightweight filling. When sprayed between the initial support and the secondary lining in this application, it has good compression characteristics. Therefore, when encountering later rheological deformation, it can produce a relatively large compression deformation, thereby consuming and releasing the surrounding rock load transmitted from the initial support, and further reducing the risk of the initial support itself being damaged by torsion, fracture, etc. due to rheological deformation, thereby improving the overall stability and reliability of the support structure.

[0015] Furthermore, along the radial direction of the tunnel, the thickness of the yield concrete layer is greater than the thickness of the yield member located in the yield concrete layer.

[0016] This ensures that when the surrounding rock undergoes rheological deformation, the compressive properties of the yielding concrete layer first dissipate the surrounding rock load. At this point, the yielding members within the yielding concrete layer provide sufficient rigidity to maintain support between the primary support and the secondary lining. Once the thickness of the yielding concrete layer is equal to or less than the thickness of the yielding members within it, the yielding members within it provide a load dissipation channel, ensuring graded and phased control of rheological deformation and extending the effective working life of the support structure.

[0017] Furthermore, the pressure-releasing member includes a first elliptical tube and a second elliptical tube whose end faces face each other; the first elliptical tube and the second elliptical tube are rotatably connected, and the rotation axis passes through the center point of the end face of the first elliptical tube and the center point of the end face of the second elliptical tube.

[0018] The first and second elliptical tubes in this application are pipe structures with elliptical cross-sections. When radial pressure is required for the yielding member, the major axes of the ellipses of the first and second elliptical tubes are oriented in the radial direction of the tunnel. When circumferential pressure is required for the yielding member, the major axes of the ellipses of the first and second elliptical tubes are perpendicular to the radial direction of the tunnel. This solution uses elliptical pipe structures as yielding members, which increases the deformation amplitude of the yielding member and, in turn, the dissipation of surrounding rock loads (including both extrusion and rheological deformation).

[0019] In addition, the existing technology has two methods for bearing pressure within the initial support: one is to use purely rigid components to bear pressure, and the other is to use flexible or elastic systems to dissipate energy. Purely rigid components have low toughness and are prone to torsion or fracture failure of the initial support when encountering large surrounding rock deformation, resulting in loss of bearing capacity. Flexible or elastic systems, on the other hand, have weak resistance to the later rheological deformation of the surrounding rock. The pressure-yielding component designed in this solution enables the first and second elliptical tubes to rotate relative to each other. Its axis of rotation passes through the center points of the end faces of the first and second elliptical tubes. Therefore, when the first and second elliptical tubes rotate relative to each other, they become misaligned and no longer face each other. This process can squeeze the external concrete and consume a large amount of energy, which is beneficial for dissipating the rheological deformation generated during tunnel operation within the support structure, extending the tunnel's service life and maintenance cycle. In addition, the structure composed of the two elliptical tubes can only rotate relative to each other, thus maintaining the good rigidity of the pressure-yielding component and ensuring sufficient pressure-bearing capacity. Therefore, the pressure-yielding member proposed in this application takes into account the dual advantages of traditional rigid and flexible systems, and ensures the bearing capacity and resistance to rheological deformation, and is particularly suitable for use in high-stress soft rock formations.

[0020] Furthermore, a first positioning member is provided on an inner wall of one end of the first elliptical tube facing the direction where the second elliptical tube is located, and a second positioning member is provided on an inner wall of one end of the second elliptical tube facing the direction where the first elliptical tube is located;

[0021] The second positioning member is fixedly connected to a rotating shaft, and the first positioning member is provided with a through hole matching the rotating shaft; the axis of the rotating shaft passes through the center point of the end face of the second elliptical tube.

[0022] This solution achieves relative rotation between the first elliptical tube and the second elliptical tube through a rotating shaft. The first and second positioning members are both compatible with the rotating shaft, with one end of the rotating shaft fixed to the first positioning member and the other end inserted into the through hole. The second elliptical tube, the second positioning member, and the rotating shaft move synchronously; the presence of the two positioning members ensures stable rotation of the rotating shaft. This rotation solution has a simple structure, facilitates rapid on-site assembly, and eliminates the need for components such as bearings, offering significant advantages in both production and installation costs. Furthermore, even if the outer wall of the elliptical tube is deformed, it can continue to maintain effective rotation capabilities.

[0023] In addition, those skilled in the art should understand that the center point of the end face of the elliptical tube in the present application is the intersection of the major axis and the minor axis of the elliptical shape of the end face.

[0024] Furthermore, a first positioning groove is provided on the end surface of the first elliptical tube facing the direction where the second elliptical tube is located, and a second positioning groove is provided on the end surface of the second elliptical tube facing the direction where the first elliptical tube is located; the first positioning groove is open on the outer wall surface of the first elliptical tube, and the second positioning groove is open on the outer wall surface of the second elliptical tube;

[0025] The second positioning groove corresponds to the first positioning groove one by one;

[0026] It also includes a shear pin, with two ends of the shear pin connected to the first positioning groove and the second positioning groove respectively.

[0027] The first and second positioning grooves in this solution are open on the outer walls and end faces of their respective corresponding elliptical tubes, making it easy to splice and connect the first and second positioning grooves after the two elliptical tubes are aligned, thereby facilitating the insertion of a shear pin from the outside inward. At this time, the two ends of the shear pin are respectively connected to the first and second positioning grooves, and the connection between the first and second elliptical tubes can be achieved through the shear pin. When the external load is large and the loads acting on the first and second elliptical tubes are different, and the two elliptical tubes tend to rotate relative to each other, the shear pins need to be cut first to achieve relative rotation. The shear pins can further improve the energy dissipation capacity of the pressure component.

[0028] Furthermore, the bottoms of the first positioning groove and the second positioning groove are respectively provided with a first threaded blind hole and a second threaded blind hole; the shear pin is provided with a first threaded through hole and a second threaded through hole corresponding to the first threaded blind hole and the second threaded blind hole respectively;

[0029] It also includes a first cover body and a second cover body for being installed in the first positioning groove and the second positioning groove respectively; the first cover body and the second cover body are respectively provided with a third threaded through hole and a fourth threaded through hole matching the first threaded through hole and the second threaded through hole; the inner walls of the first cover body and the second cover body are both provided with an arc groove matching the shear pin.

[0030] During installation, the first and second threaded holes on the shear pin are aligned with the first and second threaded blind holes, respectively. The first and second covers are then installed, with the third and fourth threaded holes aligned with the first and second threaded holes, respectively. This allows two sets of bolts to securely connect the first and second covers, the shear pin, and the first and second elliptical tubes. This connection ensures that the shear pin does not break.

[0031] Furthermore, for the pressure-yielding members located in the initial support, the short axes of the end faces of the first elliptical tube and the second elliptical tube are distributed radially along the tunnel; therefore, their corresponding long axes can be approximately considered to be distributed circumferentially along the tunnel, so that the pressure-yielding members in the initial support can better consume the mutual extrusion and / or tensile deformation energy between the various parts of the steel arch frame in the initial support, thereby better consuming short-term extrusion deformation energy.

[0032] For the yielding member located in the yielding concrete layer, the long axes of the end faces of the first and second elliptical tubes are distributed along the radial direction of the tunnel; this arrangement is conducive to providing a larger deformation space for the two elliptical tubes to consume long-term rheological deformation energy.

[0033] Furthermore, the yield member further includes a connecting plate fixedly connected to the first elliptical tube and parallel to the axis of the first elliptical tube. The connecting plate is used to connect to existing components within the initial support and / or within the yield concrete layer to achieve the installation of the yield member of the present application.

[0034] In addition, the connecting plate of the present invention is fixedly connected to the first elliptical tube but not to the second elliptical tube. The connecting plate is fixed in the initial support or yield concrete layer. When the initial support or yield concrete layer is subjected to stress and undergoes local deformation, the first elliptical tube fixedly connected to the connecting plate is relatively stable, while the connecting plate is more likely to squeeze the second elliptical tube to cause it to move, thereby increasing the possibility of the second elliptical tube rotating relative to the first elliptical tube.

[0035] The construction method of the support structure of the present application comprises the following steps:

[0036] S1. Excavate the tunnel and install anchor bolts;

[0037] S2. Set up the initial support, during which several pressure-relieving components are installed inside the initial support;

[0038] S3. Install several pressure-relieving components on the inner wall of the initial support;

[0039] S4, sprayed yield concrete layer;

[0040] S5. Secondary lining construction.

[0041] This application can take into account the large deformation of the surrounding rock of high-stress soft rock tunnels, such as "short-term extrusion deformation" and "long-term rheological deformation", and can fully release the rheological deformation during the operation period, so as to ensure that the deformation of the initial support structure and the secondary lining is within the allowable range and its bearing capacity.

[0042] Compared with the prior art, the present invention has at least the following advantages and beneficial effects:

[0043] 1. The present invention provides a support structure and construction method that take into account both the short-term extrusion deformation and long-term rheological deformation of the tunnel surrounding rock. Through the yielding concrete layer and the yielding components located within the yielding concrete layer, the structure can fully bear the later rheological deformation of the tunnel surrounding rock under high ground stress soft rock formation conditions, thereby ensuring the stability and effectiveness of the initial support structure during long-term operation and reducing the risk of damage to the initial support structure.

[0044] 2. The present invention provides a support structure and construction method that balances short-term extrusion deformation and long-term rheological deformation of the tunnel surrounding rock. A pressure-relief member is also provided within the initial support structure, enhancing the initial support system's resistance and improving tunnel stability. This application also eliminates the existing grouting reinforcement approach and overcomes drawbacks such as the low controllability of the grouting effect and the forced delays in construction.

[0045] 3. The present invention provides a support structure and construction method that take into account both the short-term extrusion deformation and long-term rheological deformation of the tunnel surrounding rock. EPS concrete is used as the pressure-relieving concrete layer, which can produce a relatively large compression deformation when encountering later rheological deformation, thereby consuming and releasing the surrounding rock load transmitted from the initial support, and further reducing the risk of the initial support itself being damaged by torsion, fracture, etc. due to rheological deformation, thereby improving the overall stability and reliability of the support structure.

[0046] 4. The present invention provides a support structure and construction method that balances short-term extrusion deformation and long-term rheological deformation of tunnel surrounding rock. When encountering rheological deformation of the surrounding rock, the compressive properties of the yielding concrete layer are first used to dissipate the surrounding rock load. At this point, the yielding components within the yielding concrete layer provide sufficient rigidity to maintain support between the primary support and the secondary lining. When the thickness of the yielding concrete layer is equal to or less than the thickness of the yielding components within it, the yielding components within it provide a load dissipation channel, ensuring graded and phased control of rheological deformation and extending the effective operating cycle of the support structure.

[0047] 5. The present invention provides a support structure and construction method that takes into account both the short-term extrusion deformation and long-term rheological deformation of the tunnel surrounding rock, allowing the compression member to squeeze the external concrete and thereby consume a large amount of energy, which is beneficial for consuming the rheological deformation generated during the operation of the tunnel within the support structure and extending the service life and maintenance cycle of the tunnel.

[0048] 6. The present invention provides a support structure and construction method that takes into account both the short-term extrusion deformation and long-term rheological deformation of the tunnel surrounding rock. The shear pins need to be cut off first to achieve the relative rotation of the pressure-releasing member. The shear pins are used to achieve the self-connection and installation of the pressure-releasing member, and the energy consumption capacity of the pressure-releasing member is further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0050] Figure 1 A schematic cross-sectional view of a specific embodiment of the present invention;

[0051] Figure 2 This is a schematic diagram of the construction process of a specific embodiment of the present invention;

[0052] Figure 3 A schematic diagram of a compression member within an initial support structure in a specific embodiment of the present invention;

[0053] Figure 4 A schematic diagram of a compression-yielding member in a compression-yielding concrete layer in a specific embodiment of the present invention;

[0054] Figure 5 It is a cross-sectional view of a pressure-yielding member in a specific embodiment of the present invention;

[0055] Figure 6 This is a schematic structural diagram of a first elliptical tube in a specific embodiment of the present invention;

[0056] Figure 7 This is a schematic structural diagram of a second elliptical tube in a specific embodiment of the present invention;

[0057] Figure 8 This is a schematic structural diagram of a shear pin in a specific embodiment of the present invention;

[0058] Figure 9 Schematic diagram of the separation of the first cover and the second cover in a specific embodiment of the present invention.

[0059] Markings and corresponding parts names in the accompanying drawings:

[0060] 1-yield member, 101-first elliptical tube, 102-second elliptical tube, 103-first positioning member, 104-second positioning member, 105-rotating shaft, 106-through hole, 107-first positioning groove, 108-second positioning groove, 109-shear pin, 110-first threaded blind hole, 111-second threaded blind hole, 112-first threaded through hole, 113-second threaded through hole, 114-first cover, 115-second cover, 116-third threaded through hole, 117-fourth threaded through hole, 118-arc-shaped groove, 119-connecting plate;

[0061] 2-yield concrete layer, 3-initial support, 4-tip face, 5-anchor rods, 6-primary support concrete layer, 7-secondary lining, 8-steel arch frame, 9-bolts. DETAILED DESCRIPTION

[0062] In order to make the objects, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the examples and drawings. The schematic 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. In the description of this application, it should be understood that the orientations or positional relationships indicated by terms such as "front", "back", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inside", "outside", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of this application.

[0063] Example 1:

[0064] like Figures 1 to 4 The support structure shown here takes into account both the short-term extrusion deformation and long-term rheological deformation of the tunnel surrounding rock, including an initial support 3 and a secondary lining 7. A yield concrete layer 2 is provided between the initial support 3 and the secondary lining 7. Several yield components 1 are provided in both the initial support 3 and the yield concrete layer 2.

[0065] The yield concrete layer 2 is EPS concrete sprayed on the inner wall of the initial support 3.

[0066] In the radial direction of the tunnel, the thickness of the yield concrete layer 2 is greater than the thickness of the yield member 1 located within the yield concrete layer 2. If the thickness of the yield concrete layer 2 is a and the thickness of the yield member 1 within the yield concrete layer 2 is b, preferably ab ≥ 2.5 cm.

[0067] The initial support 3 in this embodiment includes a steel arch frame and a primary support concrete layer 6 sprayed on the outside of the steel arch frame. The steel arch frame is composed of several segments; in the circumferential direction, adjacent segments are connected by a yield member 1.

[0068] The specific construction method of this embodiment includes the following steps:

[0069] Step S1, excavating a tunnel and installing anchor bolts 5;

[0070] Step S2, setting up the initial support 3, during which a plurality of pressure-relieving members 1 are installed inside the initial support 3;

[0071] Step S3, installing a plurality of pressure-relieving members 1 on the inner wall of the initial support 3;

[0072] Step S4, spraying the yield concrete layer 2;

[0073] Step S5: secondary lining construction, i.e. setting a reinforced concrete layer.

[0074] Among them, the preferred tunnel excavation method is the full-section method or the up-and-down step method, the purpose of which is to allow the initial support to be closed into a ring as soon as possible to ensure the bearing capacity.

[0075] Preferably, step S2 specifically includes:

[0076] S201, erecting a steel arch frame so that adjacent segments of the steel arch frame in the circumferential direction are connected by a yield member 1;

[0077] S202: spraying a primary support concrete layer 6. During the spraying process, a position for connecting the pressure relief member 1 is reserved on the steel arch frame. In the radial direction of the tunnel, the thickness of the primary support concrete layer 6 can be equal to the thickness of the steel arch frame.

[0078] Preferably, step S3 specifically includes: welding the pressure-yielding member 1 at the work station for connecting the pressure-yielding member 1 .

[0079] In a more preferred embodiment, Figure 3 and Figure 4 As shown, the pressure-yielding member 1 comprises an elliptical steel tube;

[0080] For the yield member 1 located in the initial support 3 , the short axis of the end face of the elliptical steel tube is distributed along the radial direction of the tunnel; and the elliptical steel tube is connected to the steel arch 8 by bolts 9 .

[0081] For the yielding member 1 located in the yielding concrete layer 2 , the major axis of the end face of the elliptical steel tube is distributed along the radial direction of the tunnel; and the radially outward end of the elliptical steel tube is welded to the steel arch 8 .

[0082] Example 2:

[0083] A support structure that takes into account both short-term extrusion deformation and long-term rheological deformation of tunnel surrounding rock, based on Example 1, as Figures 5 to 9 As shown, the pressure member 1 includes a first elliptical tube 101 and a second elliptical tube 102 whose end faces face each other; the first elliptical tube 101 and the second elliptical tube 102 are rotatably connected, and the rotation axis passes through the center point of the end face of the first elliptical tube 101 and the center point of the end face of the second elliptical tube 102.

[0084] In this embodiment, the specific rotation connection method of the first elliptical tube 101 and the second elliptical tube 102 is:

[0085] A first positioning member 103 is provided on the inner wall of one end of the first elliptical tube 101 facing the second elliptical tube 102, and a second positioning member 104 is provided on the inner wall of one end of the second elliptical tube 102 facing the first elliptical tube 101. A rotating shaft 105 is fixedly connected to the second positioning member 104, and a through hole 106 is defined in the first positioning member 103 to match the rotating shaft 105. The axis of the rotating shaft 105 passes through the center point of the end face of the second elliptical tube 102. The diameter of the through hole 106 is equal to the outer diameter of the rotating shaft 105.

[0086] A first positioning groove 107 is provided on the end surface of the first elliptical tube 101 facing the second elliptical tube 102, and a second positioning groove 108 is provided on the end surface of the second elliptical tube 102 facing the first elliptical tube 101; the first positioning groove 107 is open on the outer wall of the first elliptical tube 101, and the second positioning groove 108 is open on the outer wall of the second elliptical tube 102;

[0087] The second positioning groove 108 corresponds to the first positioning groove 107 one by one;

[0088] It also includes a shear pin 109 , both ends of which are connected to the first positioning groove 107 and the second positioning groove 108 respectively.

[0089] A first threaded blind hole 110 and a second threaded blind hole 111 are respectively formed at the bottom of the first positioning groove 107 and the second positioning groove 108; a first threaded through hole 112 and a second threaded through hole 113 are respectively formed on the shear pin 109;

[0090] It also includes a first cover body 114 and a second cover body 115 for being installed in the first positioning groove 107 and the second positioning groove 108 respectively; the first cover body 114 and the second cover body 115 are respectively provided with a third threaded through hole 116 and a fourth threaded through hole 117 that match the first threaded through hole 112 and the second threaded through hole 113; the inner walls of the first cover body 114 and the second cover body 115 are both provided with an arc groove 118 that matches the shear pin 109.

[0091] In this embodiment, the first and second elliptical tubes 101, 102 have the same shape and size, and their end faces are completely aligned during initial installation. The first and second positioning members 103, 104 are both elliptical in shape, matching the internal shapes of the first and second elliptical tubes 101, 102, respectively, to achieve complete filling of the ends, thereby preventing deformation of the ends and ensuring relative rotation between the first and second elliptical tubes 101 and 102.

[0092] Preferably, the first elliptical tube 101 , the second elliptical tube 102 , the first positioning member 103 , and the second positioning member 104 are all made of steel. The first positioning member 103 and the second positioning member 104 are welded inside the first elliptical tube 101 and the second elliptical tube 102 , respectively.

[0093] Preferably, the pressure-releasing member 1 further comprises a connecting plate 119, which is fixedly connected to the first elliptical tube 101 and parallel to the axis of the first elliptical tube 101. In this embodiment, the connecting plate 3 is also perpendicular to the long axis of the end face of the first elliptical tube 101.

[0094] In a more preferred embodiment, there are two connecting plates 119, which are parallel to each other and located at both ends of the long axis of the end face of the first elliptical tube 101. When the second elliptical tube 10 is connected to the first elliptical tube 101 via the plurality of shear pins 109, the two ends of the long axis of the end face of the second elliptical tube 10 are in contact with the two connecting plates 119 respectively.

[0095] In a more preferred embodiment, the rotating shaft 105 is tubular, which is conducive to allowing part of the concrete to enter the first elliptical tube 101 and the second elliptical tube 102 during concrete spraying to improve the pressure resistance.

[0096] Example 3:

[0097] A support structure that takes into account both short-term extrusion deformation and long-term rheological deformation of tunnel surrounding rock. Based on Example 2, during construction, the pressure-yielding member 1 needs to be prepared in advance.

[0098] The installation method of the pressure member 1 is:

[0099] Insert the rotating shaft 105 into the through hole 106 so that the end surfaces of the first elliptical tube 101 and the second elliptical tube 102 abut against each other;

[0100] Adjust the orientation of the first elliptical tube 101 and / or the second elliptical tube 102 so that the end faces of the first elliptical tube 101 and the second elliptical tube 102 face each other, that is, the first positioning groove 107 and the second positioning groove 108 face each other one by one;

[0101] In each set of opposite first positioning grooves 107 and second positioning grooves 108: a shear pin 109 is installed so that the first threaded through hole 112 and the second threaded through hole 113 on the shear pin 109 are respectively aligned with the first threaded blind hole 110 and the second threaded blind hole 111; then, a first cover 114 and a second cover 115 are respectively installed in the first positioning grooves 107 and the second positioning grooves 108, and the third threaded through hole 116 and the fourth threaded through hole 117 are respectively aligned with the first threaded through hole 112 and the second threaded through hole 113; and two sets of bolts are used to achieve fixed connection between the first cover, the second cover, the shear pins and the first elliptical tube and the second elliptical tube;

[0102] Weld the connecting plate 119 .

[0103] Example 4:

[0104] A support structure that takes into account both short-term extrusion deformation and long-term rheological deformation of tunnel surrounding rock. Based on any of the above embodiments, the EPS concrete includes the following components:

[0105] Portland cement, 200~250kg / m³;

[0106] EPS (expanded polystyrene) particles with a particle size of 5-8 mm, 6-10 kg / m³;

[0107] Rubber particles with a particle size of 1-3 mm, 20-50 kg / m³;

[0108] Flexible acrylic, 25~40 kg / m³;

[0109] Polypropylene fibers with a length of 12-18 mm, 1.5-2.5 kg / m³;

[0110] Concrete air entraining agent, 0.1~ 0.3 kg / m³;

[0111] Silane coupling agent, in appropriate amount, is used to ensure strong bonding between EPS particles and the matrix to prevent premature failure of the interface.

[0112] Compared to traditional EPS concrete, this solution uses less cement and supplements the matrix with flexible acrylic, which facilitates the formation of a flexible three-dimensional network after curing, improving ductility. Furthermore, EPS particles and rubber particles form a dual-grade flexible aggregate. The large EPS particles provide macroscopic compression deformation space, enhancing energy dissipation, while the high content of rubber particles significantly increases the toughness of the yield concrete layer, also contributing to improved energy dissipation. Furthermore, polypropylene fibers prevent crack penetration, enhancing the bearing capacity of the yield concrete layer after stress cracking.

[0113] The EPS concrete provided in this embodiment can be used exclusively in the yield concrete layer of this application and has an excellent energy absorption effect.

[0114] 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.

[0115] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises", or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In addition, the term "connected" as used in this document, unless otherwise specified, may refer to a direct connection or an indirect connection via other components.

Claims

1. A support structure that takes into account both short-term extrusion deformation and long-term rheological deformation of tunnel surrounding rock, comprising initial support (3) and secondary lining, characterized in that: A yield concrete layer (2) is provided between the initial support and the secondary lining, and a plurality of yield components (1) are provided in both the initial support (3) and the yield concrete layer (2).

2. A support structure that takes into account both short-term extrusion deformation and long-term rheological deformation of tunnel surrounding rock according to claim 1, characterized in that: The yield concrete layer (2) is EPS concrete sprayed on the inner wall of the initial support (3).

3. The support structure according to claim 1 that takes into account both short-term extrusion deformation and long-term rheological deformation of tunnel surrounding rock, characterized in that: Along the radial direction of the tunnel, the thickness of the yield concrete layer (2) is greater than the thickness of the yield member (1) located in the yield concrete layer (2).

4. The support structure according to claim 1 that takes into account both short-term extrusion deformation and long-term rheological deformation of tunnel surrounding rock, characterized in that: The pressure-releasing member (1) comprises a first elliptical tube (101) and a second elliptical tube (102) whose end faces face each other; the first elliptical tube (101) and the second elliptical tube (102) are rotatably connected, and the rotation axis passes through the center point of the end face of the first elliptical tube (101) and the center point of the end face of the second elliptical tube (102).

5. A support structure that takes into account both short-term extrusion deformation and long-term rheological deformation of tunnel surrounding rock according to claim 4, characterized in that: A first positioning member (103) is provided on the inner wall of one end of the first elliptical tube (101) facing the direction where the second elliptical tube (102) is located, and a second positioning member (104) is provided on the inner wall of one end of the second elliptical tube (102) facing the direction where the first elliptical tube (101) is located; The second positioning member (104) is fixedly connected to a rotating shaft (105), and the first positioning member (103) is provided with a through hole (106) matching the rotating shaft (105); the axis of the rotating shaft (105) passes through the center point of the end face of the second elliptical tube (102).

6. The support structure according to claim 4 that takes into account both short-term extrusion deformation and long-term rheological deformation of tunnel surrounding rock, characterized in that: A first positioning groove (107) is provided on the end surface of the first elliptical tube (101) facing the direction of the second elliptical tube (102), and a second positioning groove (108) is provided on the end surface of the second elliptical tube (102) facing the direction of the first elliptical tube (101); the first positioning groove (107) is open on the outer wall surface of the first elliptical tube (101), and the second positioning groove (108) is open on the outer wall surface of the second elliptical tube (102); The second positioning groove (108) corresponds one-to-one to the first positioning groove (107); It also includes a shear pin (109), with two ends of the shear pin (109) respectively connected to the first positioning groove (107) and the second positioning groove (108).

7. A support structure that takes into account both short-term extrusion deformation and long-term rheological deformation of tunnel surrounding rock according to claim 6, characterized in that: A first threaded blind hole (110) and a second threaded blind hole (111) are respectively formed at the bottoms of the first positioning groove (107) and the second positioning groove (108); a first threaded through hole (112) and a second threaded through hole (113) are respectively formed on the shear pin (109); The invention also includes a first cover body (114) and a second cover body (115) for being respectively installed in the first positioning groove (107) and the second positioning groove (108); a third threaded through hole (116) and a fourth threaded through hole (117) are respectively provided on the first cover body (114) and the second cover body (115) to match the first threaded through hole (112) and the second threaded through hole (113); and an arc groove (118) is provided on the inner wall of the first cover body (114) and the second cover body (115) to match the shear pin (109).

8. The support structure according to claim 4 that takes into account both short-term extrusion deformation and long-term rheological deformation of tunnel surrounding rock, characterized in that: For the pressure-yielding member (1) located in the initial support (3), the short axes of the end faces of the first elliptical tube (101) and the second elliptical tube (102) are distributed along the radial direction of the tunnel; For the yielding member (1) located in the yielding concrete layer (2), the end face major axes of the first elliptical tube (101) and the second elliptical tube (102) are distributed along the radial direction of the tunnel.

9. The support structure according to claim 4 that takes into account both short-term extrusion deformation and long-term rheological deformation of tunnel surrounding rock, characterized in that: The pressure-releasing member (1) further comprises a connecting plate (119), wherein the connecting plate (119) is fixedly connected to the first elliptical tube (101), and the connecting plate (119) is parallel to the axis of the first elliptical tube (101).

10. A construction method for a support structure that takes into account both short-term extrusion deformation and long-term rheological deformation of tunnel surrounding rock according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Excavate the tunnel and install anchor bolts; S2, setting up the initial support (3), during which a plurality of pressure-relieving members (1) are installed inside the initial support (3); S3, installing a plurality of pressure-releasing members (1) on the inner wall of the initial support (3); S4, shotcrete layer (2); S5. Secondary lining construction.

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