A reinforcement and support structure for the portal of a group of tunnels in complex bad geological conditions

Abstract

The present invention discloses a reinforcement and support structure for the portal of a complex tunnel group in poor geological conditions, which successively includes a grouting and anchoring structure, an inner steel plate layer, a steel support grid layer, a corrugated steel plate, a strengthening support frame, and a surface steel plate layer from top to bottom; concrete is filled between the grouting and anchoring structure and the inner steel plate layer, concrete is filled between the inner steel plate layer and the corrugated steel plate, the steel support grid layer is covered by concrete, concrete is filled between the corrugated steel plate and the surface steel plate layer, and the strengthening support frame is covered by concrete. The present invention can solve the problem that the surrounding rock at the portal of a complex tunnel group in poor geological conditions undergoes large deformation, causing the destruction of the tunnel structure in the prior art. The support system is simple, the force system conversion is reasonable, the support cost is reduced, and the construction safety of the portal under the environment of a complex tunnel group in poor geological conditions is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel engineering construction, and in particular, to a reinforcement and support structure for the portal of a complex tunnel group in poor geological conditions. Background Art

[0002] In the construction of subway tunnels, as the connection between the shaft and the roadway of the yard, the stress state of the portal is very complex. Especially under special conditions such as thick overburden and thin bedrock in the portal area, the construction of large-section portals has a large influence range and serious stress concentration. Affected by the subsequent roadway construction, the surrounding rock is disturbed multiple times, with large deformation and easy instability, resulting in the damage of the portal support structure. Due to the thin bedrock section and the close distance between the wall foundation of the shaft lining in the overburden section and the portal, the damage of the portal support structure will cause the rupture of the shaft lining in the overburden section, endangering the safety of the tunnel.

[0003] The construction of the mined portal of a complex tunnel group poses a greater challenge to the safety of the tunnel structure. Especially in the construction of a complex tunnel group in poor geological conditions, the excavation of each pilot tunnel will have an impact on each other. The excavation of the front tunnel will cause stress redistribution of the surrounding rock, and during the excavation of the rear tunnel, the stress of the surrounding rock will be disturbed again, easily leading to excessive deformation of the surrounding rock of the rear tunnel. At the same time, the secondary disturbance of the stress of the surrounding rock of the front tunnel increases the force on the primary support structure. If the primary support structure deforms or is stressed too much, it will have a significant impact on the safety of the tunnel structure. For a complex tunnel group, its cross-section is larger, the process of removing the portal and entering the tunnel is more, the stress field superposition effect is more significant, and the possibility of instability of the surrounding rock and structure is greater. At the same time, there are greater risks in the portal project of a complex tunnel group itself, and the safety control of the structure during construction should be highly emphasized to avoid instability and damage.

[0004] Therefore, in view of the current construction status, there is an urgent need to develop a reinforcement construction structure for the portal of a complex tunnel group in poor geological conditions to meet the requirements of safe and reliable construction. Summary of the Invention

[0005] In order to solve the defects in the prior art, the present invention provides a reinforcement and support structure for the portal of a complex tunnel group in poor geological conditions. The present invention can solve the problem that the surrounding rock at the portal of a complex tunnel group in poor geological conditions undergoes large deformation, causing damage to the tunnel structure. The support system is simple, the force system conversion is reasonable, the support cost is reduced, and the construction safety of the portal under the environment of a complex tunnel group in poor geological conditions is greatly improved.

[0006] To achieve the above object, the present invention provides a reinforcement and support structure for the portal of a tunnel group in poor geological conditions, which sequentially includes a grouting and anchoring structure, an inner steel plate layer, a steel support grid layer, a corrugated steel plate, a strengthening support frame, and a surface steel plate layer from top to bottom; concrete is filled between the grouting and anchoring structure and the inner steel plate layer, between the inner steel plate layer and the corrugated steel plate, the steel support grid layer is covered by concrete, between the corrugated steel plate and the surface steel plate layer, and the strengthening support frame is covered by concrete;

[0007] The grouting and anchoring structure includes grouting and anchoring rods and grouting liquid. A plurality of grouting holes are provided on the grouting and anchoring rods. The grouting and anchoring rods are anchored in the surrounding rock of the portal. The grouting liquid is injected into the surrounding rock through the grouting holes of the grouting and anchoring rods by grouting equipment and forms a grouting and anchoring structure after solidification. One end of the grouting and anchoring rod leaks out of the surface of the surrounding rock when it is anchored in the surrounding rock of the portal;

[0008] The inner steel plate layer passes through the end of the grouting and anchoring rod that leaks out of the surface of the surrounding rock, adheres to the surface of the surrounding rock, and is fixed on the grouting and anchoring rod;

[0009] The steel support grid layer is composed of multiple steel structure columns that intersect vertically and horizontally. Its overall structural form is adapted to the shape of the portal, and the multiple steel structure columns are connected by a mortise and tenon structure, and the inner steel plate layer is supported and reinforced;

[0010] The strengthening support frame is composed of multiple vertical supports, horizontal supports, and diagonal supports. It is fixed around the space of the portal and supports the corrugated steel plate. The multiple vertical supports, horizontal supports, and diagonal supports are connected by a mortise and tenon structure.

[0011] Preferably, after the inner steel plate layer is fixed on the grouting and anchoring rod, concrete is filled between the surface of the surrounding rock and the inner steel plate layer to fill the gap between the two; the corrugated steel plate is fixed on the steel support grid layer, and then concrete is filled between the inner steel plate layer and the corrugated steel plate to fill the gap between the two.

[0012] In any of the above solutions, preferably, the grouting and anchoring rods and the surface steel plate layer are fixed on the strengthening support frame, and then concrete is filled between the corrugated steel plate and the surface steel plate layer to fill the gap between the two.

[0013] In any of the above solutions, preferably, the mortise and tenon structure includes Z-shaped grooves and Z-shaped protrusions provided between multiple steel structure columns and between multiple vertical supports, horizontal supports, and diagonal supports. Shock-absorbing elements are respectively arranged on the Z-shaped protrusions along the vertical and horizontal directions; after the mortise and tenon structure is connected, a connecting steel plate is arranged on the surface of the connection, and the connecting steel plate is fastened to the mortise and tenon structure by bolts.

[0014] Preferably, in any of the above solutions, when constructing the reinforcement and support structure of the portal, in accordance with the principle of starting from the large section and constructing symmetrically, first construct the portal of the tunnel with a large cross-section, and then symmetrically construct the adjacent tunnel portals in sequence. The longitudinal distance between adjacent working faces is staggered by 10-15 m.

[0015] Preferably, in any of the above solutions, all steel structure members, inner steel plate layers, steel support grid layers, steel corrugated plates, strengthening support frames and surface steel plate layers are subjected to anti-corrosion treatment.

[0016] Preferably, in any of the above solutions, when setting the strengthening support frame, while ensuring its support effect, the principle of occupying less tunnel space is taken into account, that is, it is close to the steel corrugated plate and the overall structure has a small spatial dimension.

[0017] Preferably, in any of the above solutions, after the construction of the reinforcement and support structure of the portal is completed, pressure detection devices are arranged at multiple positions to monitor and analyze the stress and deformation states of the portal in real time.

[0018] Advantages of the present invention:

[0019] 1. The present invention can solve the problem that the surrounding rock at the portal of the complex tunnel group in poor geological conditions undergoes large deformation, causing damage to the tunnel structure in the prior art. The support system is simple, the force system conversion is reasonable, the support cost is reduced, and the construction safety of the portal under the environment of the complex tunnel group in poor geological conditions is greatly improved.

[0020] 2. The support and reinforcement structure of the present invention can greatly improve the strength and effect of support and reinforcement, and effectively eliminate the adverse effects of the complex tunnel group effect; in addition, the present invention synchronously strengthens the monitoring of the stress and deformation of the force conversion system and the support and reinforcement structure during the structure construction, and controls and adjusts according to the monitoring information feedback, which is particularly suitable for the special conditions of the complex tunnel group in poor geological conditions.

[0021] 3. In the support and reinforcement structure of the present invention, the grouting and anchoring structure can enhance the surrounding rock strength of the portal and reduce settlement and deformation; the inner steel plate layer adheres to the surface of the overall surrounding rock of the portal to further reinforce the surrounding rock strength, enabling it to have sufficient ability to transfer stress; the steel support grid layer overall strengthens the support and reinforcement effect on the portal, playing the role of the first reinforcement effect; the steel corrugated plate forms an integral support structure and ensures the effect of increasing the volume of the cast-in-place concrete under limited space conditions, further enhancing the structural strength; the strengthening support frame plays the role of supplementing and strengthening the support effect, enabling the overall support and reinforcement structure to maximize the overall structural strength and stability of the portal and ensuring the clearance of the tunnel; the surface steel plate layer prevents the overall support and reinforcement structure from dropping surrounding rock or concrete residues when the portal structure settles or is damaged and deformed, and further makes the support and reinforcement structure integral; and the provided mortise and tenon structure can further ensure the stability of the overall structure when the support and reinforcement structure is vibrated, and also has an earthquake resistance effect, further strengthening the connection strength. Thus, the various structures of the support and reinforcement structure of the present invention cooperate with each other, and the overall structural performance is stable and safe. Specific embodiments

[0022] The technical solutions of the present application will be described in detail below in combination with the specific embodiments of the present application. However, the following embodiments are only for understanding the present invention. The embodiments in the present application and the features in the embodiments can be combined with each other. The present application can be implemented in multiple different ways defined and covered by the claims.

[0023] Example 1

[0024] A reinforcement and support structure for the portal of a complex tunnel group in poor geological conditions, which successively includes a grouting and anchoring structure, an inner steel plate layer, a steel support grid layer, a steel corrugated plate, a strengthening support frame, and a surface steel plate layer from top to bottom; the space between the grouting and anchoring structure and the inner steel plate layer is filled with concrete, the space between the inner steel plate layer and the steel corrugated plate is filled with concrete, the steel support grid layer is covered by concrete, the space between the steel corrugated plate and the surface steel plate layer is filled with concrete, and the strengthening support frame is covered by concrete;

[0025] The grouting and anchoring structure includes grouting and anchoring rods and grouting fluid. Multiple grouting holes are provided on the grouting and anchoring rods. The grouting and anchoring rods are anchored in the surrounding rock of the portal. The grouting fluid is injected into the surrounding rock through the grouting holes of the grouting and anchoring rods by grouting equipment and forms a grouting and anchoring structure after solidification. One end of the grouting and anchoring rod leaks out of the surrounding rock surface when anchored in the surrounding rock of the portal;

[0026] The inner steel plate layer passes through the end of the grouting and anchoring rod that leaks out of the surrounding rock surface, adheres to the surrounding rock surface, and is fixed on the grouting and anchoring rod;

[0027] The steel support grid layer is composed of multiple steel structure columns crisscrossing vertically and horizontally. Its overall structural form is adapted to the shape of the portal, and the multiple steel structure columns are connected by mortise and tenon structures, and the inner steel plate layer is supported and reinforced;

[0028] The strengthening support frame is composed of multiple vertical braces, horizontal braces and diagonal braces. It is fixed around the space of the portal and supports the corrugated steel plate. The multiple vertical braces, horizontal braces and diagonal braces are connected by mortise and tenon structures.

[0029] After the inner steel plate layer is fixed on the grouting anchor rod, concrete is poured full between the surrounding rock surface and the inner steel plate layer to fill the gap between the two; the corrugated steel plate is fixed on the steel support grid layer, and then concrete is poured full between the inner steel plate layer and the corrugated steel plate to fill the gap between the two.

[0030] The grouting anchor rod and the surface steel plate layer are fixed on the strengthening support frame, and then concrete is poured full between the corrugated steel plate and the surface steel plate layer to fill the gap between the two.

[0031] The mortise and tenon structure includes Z-shaped grooves and Z-shaped protrusions arranged between multiple steel structure columns and between multiple vertical braces, horizontal braces and diagonal braces. Shock-absorbing elements are respectively arranged on the Z-shaped protrusions along the vertical and horizontal directions; after the mortise and tenon structure is connected, a connecting steel plate is arranged on the surface of the connection, and the connecting steel plate is fastened to the mortise and tenon structure by bolts.

[0032] When constructing the reinforcement support structure of the portal, in accordance with the principle of constructing from large to small and symmetrically, first construct the tunnel portal with a large cross-section, and then symmetrically construct the adjacent tunnel portals in sequence. The adjacent working faces are longitudinally staggered by 10 m.

[0033] All steel structure components, inner steel plate layer, steel support grid layer, corrugated steel plate, strengthening support frame and surface steel plate layer are subjected to anti-corrosion treatment.

[0034] When setting the strengthening support frame, while ensuring its support effect, the principle of occupying less tunnel space is considered, that is, it is close to the corrugated steel plate and the space size of the overall structure is thin.

[0035] After the construction of the reinforcement support structure of the portal is completed, pressure detection devices are set at multiple positions to monitor and analyze the stress and deformation states of the portal in real time.

[0036] Embodiment 2

[0037] A reinforcement and support structure for the horsehead portal of a complex tunnel group in poor geological conditions, which successively includes a grouting and anchoring structure, an inner steel plate layer, a steel support grid layer, a corrugated steel plate, a strengthening support frame, and a surface steel plate layer from top to bottom; the space between the grouting and anchoring structure and the inner steel plate layer is filled with concrete, the space between the inner steel plate layer and the corrugated steel plate is filled with concrete, the steel support grid layer is covered by concrete, the space between the corrugated steel plate and the surface steel plate layer is filled with concrete, and the strengthening support frame is covered by concrete;

[0038] The grouting and anchoring structure includes grouting and anchoring rods and grouting liquid. Multiple grouting holes are provided on the grouting and anchoring rods. The grouting and anchoring rods are anchored in the surrounding rock of the horsehead portal. The grouting liquid is injected into the surrounding rock through the grouting holes of the grouting and anchoring rods by grouting equipment and forms a grouting and anchoring structure after solidification. One end of the grouting and anchoring rod leaks out of the surface of the surrounding rock when anchored in the surrounding rock of the horsehead portal;

[0039] The inner steel plate layer passes through the end of the grouting and anchoring rod that leaks out of the surface of the surrounding rock, adheres to the surface of the surrounding rock, and is fixed on the grouting and anchoring rod;

[0040] The steel support grid layer is composed of multiple steel structure columns that crisscross. Its overall structural form is adapted to the shape of the horsehead portal. The multiple steel structure columns are connected by a mortise and tenon structure and support and reinforce the inner steel plate layer;

[0041] The strengthening support frame is composed of multiple vertical supports, horizontal supports, and diagonal supports. It is fixed around the space of the horsehead portal and supports the corrugated steel plate. The multiple vertical supports, horizontal supports, and diagonal supports are connected by a mortise and tenon structure.

[0042] After the inner steel plate layer is fixed on the grouting and anchoring rod, the space between the surface of the surrounding rock and the inner steel plate layer is filled with concrete to fill the gap between the two; the corrugated steel plate is fixed on the steel support grid layer, and then the space between the inner steel plate layer and the corrugated steel plate is filled with concrete to fill the gap between the two.

[0043] The grouting and anchoring rod and the surface steel plate layer are fixed on the strengthening support frame, and then the space between the corrugated steel plate and the surface steel plate layer is filled with concrete to fill the gap between the two.

[0044] The mortise and tenon structure includes Z-shaped grooves and Z-shaped protrusions provided between multiple steel structure columns and between multiple vertical supports, horizontal supports, and diagonal supports. Shock-absorbing elements are respectively arranged on the Z-shaped protrusions along the vertical and horizontal directions; after the mortise and tenon structure is connected, a connecting steel plate is arranged on the surface of the connection, and the connecting steel plate is fastened to the mortise and tenon structure by bolts.

[0045] During the construction of the reinforcement support structure of the portal, in accordance with the principle of constructing the larger part first and then the smaller part symmetrically, the tunnel portal with a larger cross-section is constructed first, and then the adjacent tunnel portals are constructed symmetrically in sequence, with a longitudinal stagger of 15 m between adjacent working faces.

[0046] All steel structure components, inner steel plate layers, steel support grid layers, corrugated steel plates, strengthening support frames, and surface steel plate layers are subjected to anti-corrosion treatment.

[0047] When setting the strengthening support frame, while ensuring its support effect, the principle of occupying less tunnel space is considered, that is, it is closely attached to the corrugated steel plate and the overall structural space size is thin.

[0048] After the construction of the reinforcement support structure of the portal is completed, pressure detection devices are set at multiple positions to monitor and analyze the stress and deformation states of the portal in real time.

[0049] In addition, in order to further improve the technical effect of the present invention, in this embodiment, the scope of support reinforcement ranges from 6 m above the portal to 4.5 m below the foundation and extends 3 m into the portal. The grouting pressure is 5.5 MPa, and sealing rubbers are provided at the joints between the inner steel plate layer, corrugated steel plate, and surface steel plate layer and the corresponding structures to play the role of stopping grout and resisting grouting pressure.

[0050] A plurality of reverse hook structures are provided on the surface of the grouting anchor rod, so that when the grouting anchor rod is anchored into the surrounding rock of the portal, it is ensured that the grouting anchor rod will not fall off from it at all, and together with the grouting liquid poured later, the anchoring and strengthening effect on the portal is improved.

[0051] The grouting liquid is composed of 52.5R cement, sodium silicate, sodium phosphate, and steel fibers with a diameter of 0.05 mm, and the weight ratio is 10:5:3:2. Using the above grouting liquid can greatly improve the structural strength of the surrounding rock of the portal.

[0052] In this embodiment, the support reinforcement structure maximally ensures the safety of existing surrounding buildings during construction, while ensuring construction efficiency, reducing construction land use, and lowering project costs.

[0053] Embodiment 3

[0054] A reinforcement support structure for a portal of a tunnel group in complex bad geological conditions, which sequentially includes a grouting anchoring structure, an inner steel plate layer, a steel support grid layer, a corrugated steel plate, a strengthening support frame, and a surface steel plate layer from top to bottom; the space between the grouting anchoring structure and the inner steel plate layer is filled with concrete, the space between the inner steel plate layer and the corrugated steel plate is filled with concrete, the steel support grid layer is covered with concrete, the space between the corrugated steel plate and the surface steel plate layer is filled with concrete, and the strengthening support frame is covered with concrete;

[0055] The grouting and anchoring structure includes grouting anchor rods and grouting fluid. Multiple grouting holes are provided on the grouting anchor rods. The grouting anchor rods are anchored in the surrounding rock of the portal, and the grouting fluid is injected into the surrounding rock through the grouting holes of the grouting anchor rods by grouting equipment. After solidification, a grouting and anchoring structure is formed. One end of the grouting anchor rod leaks out of the surface of the surrounding rock when anchored in the surrounding rock of the portal.

[0056] The inner steel plate layer passes through the end of the grouting anchor rod that leaks out of the surface of the surrounding rock, adheres to the surface of the surrounding rock, and is fixed on the grouting anchor rod.

[0057] The steel support grid layer is composed of multiple steel structure columns that crisscross. Its overall structural form is adapted to the shape of the portal, and the multiple steel structure columns are connected by mortise and tenon structures, and the inner steel plate layer is supported and reinforced.

[0058] The strengthening support frame is composed of multiple vertical braces, horizontal braces and diagonal braces. It is fixed around the space of the portal and supports the corrugated steel plate. The multiple vertical braces, horizontal braces and diagonal braces are connected by mortise and tenon structures.

[0059] After the inner steel plate layer is fixed on the grouting anchor rod, the space between the surface of the surrounding rock and the inner steel plate layer is filled with concrete to fill the gap between them; the corrugated steel plate is fixed on the steel support grid layer, and then the space between the inner steel plate layer and the corrugated steel plate is filled with concrete to fill the gap between them.

[0060] The grouting anchor rods and the surface steel plate layer are fixed on the strengthening support frame, and then the space between the corrugated steel plate and the surface steel plate layer is filled with concrete to fill the gap between them.

[0061] The mortise and tenon structure includes Z-shaped grooves and Z-shaped protrusions provided between multiple steel structure columns and between multiple vertical braces, horizontal braces and diagonal braces. Shock-absorbing elements are respectively arranged on the Z-shaped protrusions along the vertical and horizontal directions; after the mortise and tenon structure is connected, a connecting steel plate is arranged on the surface of the connection part, and the connecting steel plate is fastened to the mortise and tenon structure by bolts.

[0062] When constructing the reinforcement and support structure of the portal, in accordance with the principle of constructing from large to small and symmetrically, first construct the tunnel portal with a large cross-section, and then successively and symmetrically construct the adjacent tunnel portals. The longitudinal distance between adjacent working faces is staggered by 125m.

[0063] All steel structure components, inner steel plate layer, steel support grid layer, corrugated steel plate, strengthening support frame and surface steel plate layer are subject to anti-corrosion treatment.

[0064] The setting of the strengthening support frame takes into account the principle of occupying less tunnel space while ensuring its support effect, that is, it is close to the corrugated steel plate and the space size of the overall structure is thin.

[0065] After the construction of the reinforcement support structure of the horseshoe heading is completed, pressure detection devices are set at multiple positions to monitor and analyze the stress and deformation states of the horseshoe heading in real time.

[0066] In addition, in order to further improve the technical effect of the present invention, in this embodiment, the steel corrugated plate comprises the following components by mass percentage: C: 1, Ni: 12, Si: 2, Mn: 1.5, Cr: 9, Mo: 4, S: 0.1, and the rest are Fe and impurity elements. It is poured into a casting machine at 1520 °C for casting; after cooling to 660 °C, heat treatment is carried out to form a steel plate.

[0067] Shot blasting treatment is carried out on the steel plate, and the rotational speed of the shot blasting machine head is 1800 revolutions per minute; cold rolling treatment is carried out, the deformation rate of the first pass of the rolling mill is 18%, and the limited rolling speed of the first and last passes is 200 m / min; straightening is carried out by a tension leveling machine, and the tension control range is 85000 kN; according to the plate shape before and after straightening, the tension leveling process of the tension leveling machine is adjusted, and the tension in the bending zone is 250% of the nominal tension.

[0068] After that, according to the size of the steel corrugated plate, numerical control programming is carried out, the feeding device is started, the steel plate is pushed forward, and automatically fed between the punches of the stamping and bending die; after positioning, the upper punch presses down to complete the first bending forming of the steel corrugated plate; the upper punch is lifted, the feeding device pushes the steel plate forward again, and then the upper punch presses down again to complete the second bending forming of the steel corrugated plate; repeating like this can complete the structural forming of the whole steel corrugated plate.

[0069] The steel corrugated plate in the present invention well eliminates internal stress, obtains good plate shape and high-quality surface. It ensures good comprehensive mechanical properties and improves the service life. Moreover, it has regular shape, good consistency, no danger, high efficiency, and can meet the needs of mass production.

[0070] It can be seen from the above embodiments that the present invention can solve the problem that the surrounding rock at the horseshoe heading of a complex tunnel group in poor geological conditions undergoes large deformation, causing the tunnel structure to be damaged. The support system is simple, the force system conversion is reasonable, the support cost is reduced, and the construction safety of the horseshoe heading in the environment of a complex tunnel group in poor geological conditions is greatly improved.

[0071] The support and reinforcement structure of the present invention can greatly improve the strength and effect of support and reinforcement, and effectively eliminate the adverse effects of the complex tunnel group effect; in addition, the present invention synchronously strengthens the monitoring of the stress and deformation of the force conversion system and the support and reinforcement structure during the structural construction, and controls and adjusts according to the monitoring information feedback, which is especially suitable for the special conditions of a complex tunnel group in poor geological conditions.

[0072] In the support and reinforcement structure of the present invention, the grouting and anchoring structure can enhance the surrounding rock strength of the portal and reduce settlement and deformation; the inner steel plate layer adheres to the surface of the overall surrounding rock of the portal to further reinforce the surrounding rock strength so that it has sufficient ability to transfer stress; the steel support grid layer overall strengthens the support and reinforcement effect on the portal and plays the role of the first strengthened support effect; the steel corrugated plate makes the support structure integral and ensures the effect of increasing the volume of poured concrete under the condition of limited space, further improving the structural strength; the strengthening support frame plays the role of supplementing and strengthening the support effect, enabling the overall support and reinforcement structure to maximize the overall structural strength and stability of the portal, and ensuring the clearance of the tunnel; the surface steel plate layer makes the overall support and reinforcement structure not drop surrounding rock or concrete residues when the portal structure settles or is damaged and deformed, and further makes the support and reinforcement structure integral; and the provided mortise and tenon structure can not only further ensure the stability of the overall structure when the support and reinforcement structure is vibrated, but also play an earthquake-resistant effect and further strengthen the connection strength.

[0073] Therefore, the various structures of the support and reinforcement structure of the present invention cooperate with each other, and the overall structural performance is stable and safe. The above is only a preferred embodiment of the present invention, and it is not a limitation of the present invention in other forms. Any person skilled in the art may use the disclosed technical content to make changes or modifications into equivalent embodiments with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution content of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A reinforcement and support structure for the portal of a complex tunnel group in poor geological conditions, characterized in that, It successively includes a grouting and anchoring structure, an inner steel plate layer, a steel support grid layer, a corrugated steel plate, a strengthening support frame, and a surface steel plate layer from top to bottom; the space between the grouting and anchoring structure and the inner steel plate layer is filled with concrete, the space between the inner steel plate layer and the corrugated steel plate is filled with concrete, the steel support grid layer is covered by concrete, the space between the corrugated steel plate and the surface steel plate layer is filled with concrete, and the strengthening support frame is covered by concrete; The grouting and anchoring structure includes grouting and anchoring rods and grouting liquid. Multiple grouting holes are provided on the grouting and anchoring rods. The grouting and anchoring rods are anchored in the surrounding rock of the portal. The grouting liquid is poured into the surrounding rock through the grouting holes of the grouting and anchoring rods by grouting equipment and forms a grouting and anchoring structure after solidification. One end of the grouting and anchoring rod leaks out of the surface of the surrounding rock when anchored in the surrounding rock of the portal; The inner steel plate layer passes through the end of the grouting and anchoring rod that leaks out of the surface of the surrounding rock, adheres to the surface of the surrounding rock, and is fixed on the grouting and anchoring rod; The steel support grid layer is composed of multiple steel structure columns that crisscross each other. Its overall structural form is adapted to the shape of the portal. The multiple steel structure columns are connected by a mortise and tenon structure and support and reinforce the inner steel plate layer; The strengthening support frame is composed of multiple vertical braces, horizontal braces, and diagonal braces. It is fixed around the space of the portal and supports the corrugated steel plate. The multiple vertical braces, horizontal braces, and diagonal braces are connected by a mortise and tenon structure; after the inner steel plate layer is fixed on the grouting and anchoring rod, the space between the surface of the surrounding rock and the inner steel plate layer is filled with concrete to fill the gap between the two; the corrugated steel plate is fixed on the steel support grid layer, and then the space between the inner steel plate layer and the corrugated steel plate is filled with concrete to fill the gap between the two; The grouting and anchoring rods and the surface steel plate layer are fixed on the strengthening support frame, and then the space between the corrugated steel plate and the surface steel plate layer is filled with concrete to fill the gap between the two.

2. The reinforcement and support structure of the portal of the poor geological complex tunnel group according to claim 1, wherein, The mortise and tenon structure includes Z-shaped grooves and Z-shaped protrusions provided between multiple steel structure columns and between multiple vertical braces, horizontal braces, and diagonal braces. Shock-absorbing elements are respectively arranged on the Z-shaped protrusions along the vertical and horizontal directions; after the mortise and tenon structure is connected, a connecting steel plate is arranged on the surface of the connection, and the connecting steel plate is fastened to the mortise and tenon structure by bolts.

3. The reinforcement and support structure of the portal of the tunnel group in poor geological conditions according to claim 2, characterized in that, When constructing the reinforcement and support structure of the portal, in accordance with the principle of constructing the large section first and then the small section symmetrically, first construct the tunnel portal with a large cross-section, and then successively and symmetrically construct the adjacent tunnel portals. The longitudinal distance between adjacent working faces is staggered by 10 - 15m.

4. The reinforcement and support structure of the portal of the tunnel group in complex poor geological conditions according to claim 3, characterized in that, All steel structure components, the inner steel plate layer, the steel support grid layer, the corrugated steel plate, the strengthening support frame, and the surface steel plate layer are subjected to anti-corrosion treatment.

5. The reinforcement and support structure of the portal of the poor geological complex tunnel group according to claim 4, characterized in that, The setting of the strengthening support frame takes into account the principle of occupying less tunnel space while ensuring its support effect, that is, it is closely attached to the corrugated steel plate and the overall structural space size is thin.

6. The reinforcement and support structure of the portal of the tunnel group in poor geological conditions according to claim 5, characterized in that, After the construction of the reinforcement and support structure of the portal is completed, pressure detection devices are arranged at multiple positions to monitor and analyze the stress and deformation states of the portal in real time.