Anti-impact load hole composite structure

Abstract

The utility model discloses a portal composite structure capable of preventing impact load. The portal composite structure comprises an arched portal structure and a gravel concrete cushion layer, wherein the arched portal structure extends out of a mountain and is connected with a tunnel in the mountain, and the gravel concrete cushion layer is laid below the portal structure. The tunnel portal structure comprises a foam concrete secondary lining layer, a primary support layer and a ceramsite resin concrete buffer layer which are fixedly connected in sequence from inside to outside, and the upper end of the ceramsite resin concrete buffer layer is fixedly connected with a gabion cage buffer layer; the gabion cage buffer layer comprises a gabion cage net and a loose body filled in the gabion cage net. According to the tunnel portal structure in the scheme, the lining made of different materials is arranged, the ceramsite resin concrete buffer layer and the primary support layer surround the second foam concrete lining layer together, the stability of the whole structure is improved, and the anti-seismic performance and the impact resistance of the structure can be improved through the material characteristics of the composite layer structure; and the gravel concrete cushion layer can enhance the stability of the soft foundation.

Description

Technical Field

[0001] The utility model relates to the technical field of tunnel structures, in particular to a composite tunnel opening structure capable of resisting impact loads. Background Art

[0002] At present, tunnel construction is increasingly encountering earthquake fault zones and weak surrounding rocks, and the existing collapse and rockfall phenomena threaten tunnel safety at any time. Dangerous rockfall has become one of the main geological disasters threatening the safety of tunnels in my country. At present, the protection of slope rolling stone impact loads generally adopts shed tunnel structures to prevent and control them. However, the impact load of some rolling stones is large, and the rectangular shed tunnel cannot withstand its impact load, and areas with high earthquake intensity are more likely to suffer earthquake damage. Therefore, it is necessary to develop a new support composite structure suitable for earthquake fault zones and weak surrounding rocks, so that it can not only effectively resist the impact of falling rocks, but also ensure that the tunnel has good seismic performance.

[0003] The utility model patent with application number CN201922264311.X discloses a tunnel lining composite structure, which includes a tunnel primary support, a secondary lining structure, and an EPP waterproof layer that also serves as a pressure-relieving buffer layer. The tunnel primary support is laid along the surrounding rock surface of the tunnel to form an arched structure, and the EPP waterproof layer that also serves as a pressure-relieving buffer layer is laid all around the tunnel primary support and the secondary lining structure. The EPP waterproof layer that also serves as a pressure-relieving buffer layer structure in this patent can use its own material's compressive buffering mechanical properties to provide deformation buffer space for the surrounding rock and the tunnel primary support, and can effectively protect the secondary lining structure, prevent the secondary lining structure from being subjected to excessive loads, and ensure the safety of the secondary lining structure. However, it cannot cope with areas with high seismic intensity and is likely to be damaged by earthquakes. Moreover, in areas with soft and dangerous rocks, it cannot cope with the impact damage to the tunnel body caused by falling dangerous rocks. Utility Model Content

[0004] In view of the above-mentioned deficiencies in the prior art, the utility model provides a composite structure for a tunnel entrance that is resistant to impact loads, which solves the problem in the prior art that there is a lack of a tunnel entrance structure that can effectively resist the impact of falling rocks and ensure that the tunnel has good seismic performance.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] Provided is a composite structure of a tunnel entrance that is resistant to impact loads, comprising an arched tunnel portal structure extending out of a mountain and connected to a tunnel inside the mountain, and a crushed stone concrete cushion layer laid under the tunnel portal structure; the tunnel portal structure comprises a foam concrete secondary lining layer, a primary support layer, and a ceramsite resin concrete buffer layer that are fixedly connected in sequence from the inside to the outside, a gabion cage buffer layer is fixedly connected to the upper end of the ceramsite resin concrete buffer layer; the gabion cage buffer layer comprises a gabion cage net and a loose body filled inside the gabion cage net.

[0007] The utility model has the following beneficial effects: the crushed stone concrete cushion layer can treat the soft foundation, play the role of diffusing stress, effectively disperse the load, and improve the stability and durability of the foundation. The porosity of the foam concrete second lining layer makes the layer have a lower elastic modulus, so that it has a good absorption and dispersion effect on the impact load. And the porous structure therein can absorb part of the earthquake energy, so the layer can improve the seismic performance of the structure.

[0008] The ceramsite resin concrete buffer layer has the characteristics of multiple voids, low density, strong deformation ability, good energy absorption effect, high compressive strength and is conducive to improving the seismic performance of the building. The gabion cage buffer layer is a flexible structure with good deformation adaptability. When an earthquake occurs, the loose body in the structure will adjust itself to adapt to the deformation, and the entire structure will not be destroyed.

[0009] In summary, the portal structure in this scheme is equipped with linings of different materials. The expanded clay resin concrete buffer layer and the primary support layer together surround the foam concrete secondary lining layer, which not only improves the stability of the entire structure, but also can use the material properties of the composite layer structure itself to increase the structural seismic and impact resistance. The crushed stone concrete cushion layer can enhance the stability of the soft foundation.

[0010] Furthermore, a plurality of first connecting bars are pre-buried inside the primary support layer and are evenly arranged along the arch structure of the primary support layer, and one end of the first connecting bar away from the inside of the hole extends to the inside of the ceramsite resin concrete buffer layer. The first connecting bar plays a connecting role, and can connect the ceramsite resin concrete buffer layer and the primary support layer into a whole, which can increase the tensile strength and shear strength of the buffer layer-primary support layer, further improve the stability of the structure, and improve the seismic performance of the structure.

[0011] Furthermore, the top of the cross section of the foam concrete secondary lining layer, the primary support layer and the ceramsite resin concrete buffer layer are all round arches, and both sides are vertical walls. The outer walls of the vertical wall part of the ceramsite resin concrete buffer layer are fixedly connected to the end walls on both sides; the length of the end wall in the Z-axis direction is equal to the length of the portal structure in the Z-axis direction; the end of the first connecting bar away from the inside of the opening extends to the inside of the end wall. The first connecting bar can realize the overall connection of the end wall, the ceramsite resin concrete buffer layer and the primary support layer, and can make the force distribution between the three layers more balanced.

[0012] Furthermore, the foamed concrete secondary lining, primary support layer and ceramsite resin concrete buffer layer are all fixedly connected with bottom surfaces, and any cross section of the foamed concrete secondary lining, primary support layer and ceramsite resin concrete buffer layer is a closed line segment; the three bottom surfaces all extend into the crushed stone concrete cushion layer, and the bottom surface of the foamed concrete secondary lining, the bottom surface of the primary support layer and the bottom surface of the ceramsite resin concrete buffer layer are stacked from top to bottom in sequence, so that the portal structure maintains integrity and allows the structure to bear better stress.

[0013] Furthermore, the gabion cage buffer layer is laid along the outer contour of the arched part of the ceramsite resin concrete buffer layer, and the two ends of the gabion cage net are respectively fixed on the end walls on both sides; a number of second connecting bars are evenly pre-embedded at the upper end of the end wall, and the top of the second connecting bar extends into the gap of the loose body. The second connecting bar can make the gabion cage buffer layer and the end wall more integrated, and a number of second connecting bars can reduce the shaking of the loose body to a certain extent, which can improve the structural stability.

[0014] Furthermore, the outer walls of the first connecting bar and the second connecting bar are both provided with threads. The connecting bars are both threaded steel bars, which have greater friction force with concrete and stronger anchoring performance.

[0015] Furthermore, a green plant layer is laid on the upper surface of the buffer layer of the gabion cage, which can play a role in greening and protecting the environment, and at the same time can hide the hole and beautify its appearance.

[0016] Furthermore, the crushed stone concrete cushion layer includes a concrete layer and crushed stone aggregates that are bonded and fixed, and the crushed stone aggregates are located inside the concrete layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the front section of the composite structure of the opening to protect against impact loads;

[0018] Figure 2 Schematic diagram of the side view section of the composite structure of the opening to protect against impact loads.

[0019] Among them, 1. Foam concrete second lining layer; 2. Primary support layer; 3. Expanded clay resin concrete buffer layer; 4. Loose body; 5. Gabion cage buffer layer; 6. End wall; 7. First connecting reinforcement; 8. Second connecting reinforcement; 9. Crushed stone concrete cushion layer; 10. Mountain. DETAILED DESCRIPTION

[0020] The specific implementation methods of the utility model are described below to facilitate technical personnel in this technical field to understand the utility model, but it should be clear that the utility model is not limited to the scope of the specific implementation methods. For ordinary technical personnel in this technical field, as long as various changes are within the spirit and scope of the utility model defined and determined by the attached claims, these changes are obvious, and all utility model creations using the concept of the utility model are protected.

[0021] like Figure 1-2 As shown, the impact load-resistant tunnel entrance composite structure of the present solution includes an arched tunnel entrance structure extending out of the mountain 10 and connected to the tunnel inside the mountain 10, and also includes a crushed stone concrete cushion layer 9 laid under the tunnel entrance structure. The crushed stone concrete cushion layer 9 includes a bonded and fixed concrete layer and crushed stone aggregate, and the crushed stone aggregate is located inside the concrete layer.

[0022] The crushed stone concrete cushion layer 9 can treat soft foundations, play the role of diffusing stress, effectively disperse the load, reduce the pressure on the foundation, and at the same time play the role of drainage, reduce the possibility of dampness and weakness of the foundation, thereby accelerating the consolidation of the lower soil layer, reducing the settlement of the foundation, and improving the stability and durability of the foundation.

[0023] In order to prevent rockfall impact, some tunnels have removed the tunnel portal structure that extends out of the mountain 10, so that the tunnel entrance is flush with the mountain. However, when rocks fall, the tunnel entrance is easily blocked by rocks, causing traffic inconvenience. Setting up a tunnel portal structure can divert the rockfall, guide the rockfall to evacuate to both sides along the tunnel portal structure, and reduce the probability of blocking the tunnel entrance.

[0024] The portal structure includes a foamed concrete secondary lining layer 1, a primary support layer 2 and a ceramsite resin concrete buffer layer 3 which are fixedly connected in sequence from the inside to the outside. A gabion cage buffer layer 5 is fixedly connected to the upper end of the ceramsite resin concrete buffer layer 3. The gabion cage buffer layer 5 includes a gabion cage net and a loose body 4 filled inside the gabion cage net. Among them, the foamed concrete, ceramsite resin concrete and the gabion cage net are all materials already available in the prior art.

[0025] The porosity of the second foam concrete lining layer 1 gives it a low elastic modulus, which enables it to absorb and disperse impact loads well. Foam concrete has certain flexibility and toughness, and can produce a certain degree of deformation without being easily damaged when an earthquake occurs. The porous structure therein can absorb part of the earthquake energy, so this layer can improve the seismic performance of the structure. Secondly, it is a lightweight material, which can reduce the deadweight of the structure and reduce the load on the building.

[0026] The ceramsite resin concrete buffer layer 3 has the characteristics of multiple voids, low density, strong deformation ability, good energy absorption effect, high compressive strength and is conducive to improving the seismic performance of the building. Using it as a buffer layer can increase the thickness of the buffer layer while not significantly increasing the weight. When it is damaged by pressure, it will show layer-by-layer damage without a sudden drop in strength. It is a good energy absorbing material.

[0027] The gabion cage buffer layer 5 is a flexible structure with good deformation adaptability. When an earthquake occurs, the loose body 4 in the structure will adjust itself to adapt to deformation, and the entire structure will not be destroyed. The gabion cage is a double-twisted grid structure woven by metal wire using a hexagonal twisted weaving process. Local damage will not cause its overall damage. Even if uneven subsidence occurs, the overall structure will not produce cracks or serious problems. The loose body 4 can be composed of several blocks of stone, and the size of the block of stone must be larger than the grid size of the gabion cage to prevent the block of stone from falling.

[0028] During implementation, a green plant layer can be laid on the upper surface of the gabion cage buffer layer 5, which can play a role in greening and protecting the environment, and at the same time can hide the hole and beautify its appearance.

[0029] As an embodiment of the utility model, a plurality of first connecting ribs 7 uniformly arranged along the arch structure of the primary supporting layer 2 are pre-buried inside the primary supporting layer 2, and one end of the first connecting rib 7 away from the inside of the hole extends to the inside of the ceramsite resin concrete buffer layer 3. The first connecting rib 7 plays a connecting role, and can connect the ceramsite resin concrete buffer layer 3 and the primary supporting layer 2 into a whole, which can increase the tensile strength and shear strength of the two layers, further improve the stability of the structure, and improve the seismic performance of the structure.

[0030] The top of the cross section of the foam concrete secondary lining layer 1, the primary support layer 2 and the ceramsite resin concrete buffer layer 3 are all round arches, and both sides are vertical walls, that is, the portal structure is a round arch vertical wall structure. The outer walls of the vertical wall part of the ceramsite resin concrete buffer layer 3 are fixedly connected with end walls 6 on both sides; the length of the end wall 6 in the Z-axis direction is equal to the length of the portal structure in the Z-axis direction; the end of the first connecting rib 7 away from the inside of the portal extends to the inside of the end wall 6.

[0031] The first connecting bar 7 can realize the integral connection of the end wall 6, the ceramsite resin concrete buffer layer 3 and the primary support layer 2, which can make the force distribution between the three layers more balanced, reduce the possibility of local stress concentration, and reduce the deformation of the structure under the action of external forces such as earthquakes, thereby improving the seismic performance of the structure. The end wall 6 can support the soil and rock mass around the tunnel opening, prevent collapse, and enhance the stability and safety of the opening.

[0032] Specifically, the foamed concrete secondary lining layer 1, the primary support layer 2 and the ceramsite resin concrete buffer layer 3 are all fixedly connected with the bottom surface, and any cross section of the foamed concrete secondary lining layer 1, the primary support layer 2 and the ceramsite resin concrete buffer layer 3 is a closed line segment; the three bottom surfaces all extend into the crushed stone concrete cushion layer 9, and the bottom surface of the foamed concrete secondary lining layer 1, the bottom surface of the primary support layer 2 and the bottom surface of the ceramsite resin concrete buffer layer 3 are stacked from top to bottom in sequence. This can keep the integrity of the portal structure and make the structure better stressed.

[0033] The gabion cage buffer layer 5 is laid along the outer contour of the arched part of the ceramsite resin concrete buffer layer 3, and the two ends of the gabion cage net are respectively fixed to the end walls 6 on both sides; a number of second connecting ribs 8 are evenly pre-buried at the upper end of the end wall 6, and the top of the second connecting ribs 8 extends into the gap of the loose body 4. The second connecting ribs 8 can make the integrity of the gabion cage buffer layer 5 and the end wall 6 stronger, and a number of second connecting ribs 8 can reduce the shaking of the loose body 4 to a certain extent, and can improve the structural stability.

[0034] The outer walls of the first connecting bar 7 and the second connecting bar 8 are both provided with threads. The connecting bars are both threaded steel bars, which have greater friction between the threaded steel bars and the concrete, and have stronger anchoring performance.

[0035] The construction steps of the utility model are:

[0036] S1. Excavate the original weak foundation and use crushed stone concrete to pave the excavated pit to form a cushion layer;

[0037] S2, using cast reinforced concrete as the tunnel primary support layer 2, and pre-buried first connecting bars 7 inside, and the first connecting bars 7 extend out of the primary support layer 2 at one end away from the inside of the tunnel opening;

[0038] S3, using foamed concrete as a secondary lining to form a foamed concrete secondary lining layer 1;

[0039] S4, after the construction of the primary support layer 2 and the foamed concrete secondary lining layer 1 is completed, ceramsite resin concrete is poured on the outside of the primary support layer 2 to form a ceramsite resin concrete buffer layer 3;

[0040] S5, pouring concrete at both ends of the ceramsite resin concrete buffer layer 3 to form end walls 6, and pre-embedding second connecting bars 8 inside the end walls 6;

[0041] S6. Lay a gabion cage buffer layer 5 on the ceramsite resin concrete buffer layer 3. If necessary, lay a layer of green plants on the gabion cage buffer layer 5.

[0042] In summary, the portal structure in this scheme is provided with linings of different materials. The expanded clay resin concrete buffer layer 3 and the primary support layer 2 together surround the foam concrete secondary lining layer 1, which not only improves the stability of the entire structure, but also can utilize the material properties of the composite layer structure itself to increase the seismic and impact resistance of the structure.

Claims

1. A composite structure for an opening to resist impact loads, characterized in that: The invention comprises an arched portal structure extending out of a mountain (10) and connected to a tunnel inside the mountain (10), and a crushed stone concrete cushion layer (9) laid below the portal structure; the portal structure comprises a foam concrete secondary lining layer (1), a primary support layer (2), and a ceramsite resin concrete buffer layer (3) which are fixedly connected in sequence from the inside to the outside, and a gabion cage buffer layer (5) is fixedly connected to the upper end of the ceramsite resin concrete buffer layer (3); the gabion cage buffer layer (5) comprises a gabion cage net and a loose body (4) filled inside the gabion cage net.

2. The composite structure for preventing impact loads according to claim 1, characterized in that: A plurality of first connecting bars (7) uniformly arranged along the arched structure of the primary supporting layer (2) are pre-buried inside the primary supporting layer (2); one end of the first connecting bar (7) away from the inside of the hole extends to the inside of the ceramsite resin concrete buffer layer (3).

3. The composite structure of the hole for resisting impact load according to claim 2, characterized in that: The tops of the cross sections of the foamed concrete secondary lining layer (1), the primary supporting layer (2) and the ceramsite resin concrete buffer layer (3) are all round arches, and both sides are upright walls; the outer walls of the upright wall portion of the ceramsite resin concrete buffer layer (3) are fixedly connected to end walls (6) on both sides; the length of the end wall (6) in the Z-axis direction is equal to the length of the portal structure in the Z-axis direction; and the end of the first connecting rib (7) away from the interior of the portal extends to the interior of the end wall (6).

4. The composite structure for preventing impact loads according to claim 1, characterized in that: The foamed concrete secondary lining layer (1), the primary supporting layer (2) and the ceramsite resin concrete buffer layer (3) are all fixedly connected with bottom surfaces, and any cross section of the foamed concrete secondary lining layer (1), the primary supporting layer (2) and the ceramsite resin concrete buffer layer (3) is a closed line segment; the three bottom surfaces all extend into the crushed stone concrete cushion layer (9), and the bottom surface of the foamed concrete secondary lining layer (1), the bottom surface of the primary supporting layer (2) and the bottom surface of the ceramsite resin concrete buffer layer (3) are stacked in sequence from top to bottom.

5. The composite structure of the hole for resisting impact load according to claim 3, characterized in that: The gabion cage buffer layer (5) is laid along the outer contour of the circular arch part of the ceramsite resin concrete buffer layer (3), and the two ends of the gabion cage net are respectively fixed to the end walls (6) on both sides; a plurality of second connecting ribs (8) are evenly pre-buried at the upper ends of the end walls (6), and the tops of the second connecting ribs (8) extend into the gaps of the loose body (4).

6. The composite structure of a hole for resisting impact load according to claim 5, characterized in that: The outer walls of the first connecting rib (7) and the second connecting rib (8) are both provided with threads.

7. The composite structure of a hole for resisting impact load according to claim 1, characterized in that: The upper surface of the gabion cage buffer layer (5) is paved with a green plant layer.

8. The composite structure of a hole for resisting impact load according to claim 1, characterized in that: The crushed stone concrete cushion layer (9) comprises a concrete layer and crushed stone aggregates which are bonded and fixed, and the crushed stone aggregates are located inside the concrete layer.

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