A new type of composite tunnel insulation layer and construction technology

Abstract

The invention belongs to the technical field of tunnel construction, and discloses a novel composite tunnel insulation layer, including initial support, protective layer, insulation layer, silicate composite insulation roll felt layer and secondary lining arranged in sequence from the inside to the outside; the insulation layer includes a skeleton and a filling layer; a plurality of hexagonal through holes are arranged on the skeleton, the through holes are arranged in a honeycomb shape, the filling layer is arranged in the through holes, the material of the filling layer is polyphenolic foam material, and the material of the skeleton is silicate composite insulation roll felt; the side length of the bottom surface of the hexagonal through hole is greater than the side edge of the hexagonal through hole; the skeleton is made by pressing the silicate composite insulation roll felt into a honeycomb skeleton using a hexagonal model. The invention realizes comprehensive application in tunnels by integrating the three functions of heat insulation, waterproofing and shock absorption, which can reduce the dead weight of the insulation layer, reduce the thermal conductivity of the insulation layer, and improve the efficiency and economy of engineering construction.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel construction, and in particular relates to a novel composite tunnel insulation layer and a construction process. Background Art

[0002] With the continuous advancement of highway and railway construction in my country, many projects need to build deep and long tunnels through mountainous areas. These projects often inevitably pass through high-temperature and high-heat areas, which brings huge challenges to tunnel construction.

[0003] In high-temperature and high-heat areas, the initial temperature of the surrounding rock is very high, up to 100°C, causing the concrete to be in a high-temperature and high-heat environment. In this high-temperature environment, the hydration rate of the concrete is greatly accelerated, but the hydration heat has no time to dissipate, resulting in the early and final setting times of the concrete being advanced, the early strength being high, but the later strength decreasing, and being unable to meet the structural strength requirements. In addition, due to the influence of the high-temperature environment, a temperature difference is generated between the inner and outer surfaces of the lining concrete, thereby generating additional temperature stress, causing the concrete to crack, and its durability is also greatly reduced. In high-temperature areas, high-temperature fissure water often flows out, which will corrode the concrete and further affect its life.

[0004] At present, the materials used to improve the thermal insulation capacity of tunnels include rubber foam, rock wool, glass fiber, etc., and the construction processes mainly include veneer construction, spraying construction, etc. Although these materials and processes can meet certain thermal insulation requirements, under the special working conditions of tunnels, there are problems such as poor thermal insulation effect, long construction period, and difficult to ensure construction quality.

[0005] In tunnel projects such as high-speed railways and subways, traditional insulation materials and construction techniques have been unable to meet the demand. With the continuous advancement of tunnel projects, higher requirements have been placed on insulation materials and construction techniques, including insulation effects, construction efficiency, construction quality, and construction period. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, the present invention provides a novel composite tunnel insulation layer and a construction process to solve the problems of poor tunnel insulation effect and slow construction efficiency in the prior art.

[0007] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is: a new type of composite tunnel insulation layer, including an initial support, a protective layer, an insulation layer, a silicate composite insulation roll felt layer and a secondary lining arranged in sequence from the inside to the outside;

[0008] The heat insulating layer comprises a frame and a filling layer; a plurality of hexagonal through holes are arranged in a honeycomb pattern on the frame, the filling layer is arranged in the through holes, the material of the filling layer is polyphenolic foam material, and the material of the frame is silicate composite heat insulating rolled felt.

[0009] The beneficial effects of the present invention are as follows: the honeycomb structural material has many advantages, including low consumption, high specific strength and specific stiffness, and light weight, which can greatly reduce the amount of material used and the load; the structural material is filled with air without mutual circulation due to the characteristics of its honeycomb pore structure, and can exhibit excellent buffering performance and seismic isolation function in the tunnel; for the overall structural stability of the tunnel, the setting of the initial support and protective layer is very important, and the application of the honeycomb structural material can effectively increase the overall structural stability of the tunnel, reduce the risks and impacts of groundwater infiltration and soil loosening on the tunnel structure; the presence of the protective layer can also effectively prevent the erosion of the tunnel structure by external physical and chemical corrosion factors; the new composite tunnel thermal insulation layer adopts a sandwich insulation layer setting method, which can effectively prevent heat from being directly transferred to the secondary lining, protect the concrete material of the secondary lining, not only improve the thermal insulation performance of the tunnel, but also effectively reduce the damage of heat to the concrete material, and extend the service life of the tunnel.

[0010] Furthermore, in the above-mentioned novel composite tunnel heat insulation layer, the side length of the bottom surface of the hexagonal prism through hole is greater than the side edge of the hexagonal prism through hole.

[0011] The beneficial effects of adopting the above further scheme are: the side length of the bottom surface of the hexagonal prism through hole is greater than the side edge of the hexagonal prism through hole, which can effectively improve the connection problem between the units of the skeleton, improve the strength and stability of the structure, and ensure that it can maintain its integrity and performance under the action of external forces; at the same time, a reasonable design of the ratio of wall thickness to span can make the structure more uniform under the action of external forces, avoiding the problem of local stress concentration.

[0012] Furthermore, the skeleton of the novel composite tunnel insulation layer is manufactured by pressing the silicate composite insulation roll felt into a honeycomb skeleton using a hexagonal model.

[0013] The beneficial effects of adopting the above further scheme are: the hexagonal model for making the insulation layer skeleton has a certain flexibility and plasticity. According to specific needs, the size and shape of the hexagon can be adjusted to meet the structural requirements and insulation effects of different tunnels. This flexibility helps to enhance the adaptability and practicality of the insulation layer; each inner angle of the hexagon is 120 degrees, which means that within the skeleton of the entire insulation layer, each connection point can evenly disperse the load and pressure, which is conducive to bearing a large amount of external force, reducing the concentration of local stress, and improving the overall strength and stability of the skeleton.

[0014] Furthermore, the construction method of the novel composite tunnel insulation layer comprises the following steps:

[0015] S1, initial support construction of surrounding rock;

[0016] S2, construct the thermal insulation layer on the outside of the initial support, and evenly apply a layer of anchoring glue on the back of the thermal insulation layer frame. The anchoring glue is used as a protective layer;

[0017] S3, attach the frame coated with anchoring glue to the initial support;

[0018] S4, filling the through holes of the frame with polyphenolic foam material, allowing the polyphenolic foam material to automatically foam at high temperature to fill the gaps in the through holes;

[0019] S5, laying a silicate composite thermal insulation felt layer, applying polyurethane glue on the silicate composite thermal insulation felt, pasting the whole silicate composite thermal insulation felt on the thermal insulation layer, compacting it firmly, mixing anti-cracking mortar with glue powder, No. 425 cement, fine sand and accelerator, and evenly applying it on the silicate composite thermal insulation felt insulation board;

[0020] S6, carry out secondary lining construction, bury mesh cloth on the outside of the silicate composite insulation roll felt layer, and cover the mesh cloth with sprayed concrete.

[0021] The beneficial effects of adopting the above further scheme are as follows: polyphenolic foam material is an excellent thermal insulation material, which has a low thermal conductivity and a high closed-pore rate, can effectively reduce heat conduction and loss, provide good thermal insulation effect, help maintain the temperature difference between the inside and outside of the tunnel, and reduce energy consumption; by coating the back of the skeleton with anchoring glue and sticking it on the initial support concrete structure, the bonding force between the thermal insulation layer and the concrete structure can be effectively enhanced, and the overall stability and crack resistance can be improved; after the surface of the insulation roll felt is coated with polyurethane glue, a uniform protective layer can be formed to improve the insulation roll felt. The durability and water resistance of the thermal insulation layer can protect it from moisture, corrosion and other factors, extending its service life; using anti-cracking mortar to plaster the laid silicate composite insulation roll felt insulation board can enhance the anti-cracking performance of the thermal insulation layer. The anti-cracking mortar has certain flexibility and toughness, which can effectively prevent cracks in the thermal insulation layer and improve the overall stability; by burying the mesh cloth and covering it with secondary lining concrete, the thermal insulation layer can form a closer connection with the surrounding structure, thereby improving the overall structural firmness and ensuring safety in natural disasters such as earthquakes.

[0022] Furthermore, in the construction process of the above-mentioned new composite tunnel insulation layer, the connection between the insulation layer and the initial support and secondary lining adopts an anchor bonding method.

[0023] Furthermore, in the above-mentioned novel composite tunnel insulation layer, two adjacent honeycomb frames are connected by built-in connecting pieces, convex-concave connections or screws.

[0024] The beneficial effects of adopting the above further scheme are: the built-in connecting parts connection, convex-groove connection or screw connection can enhance the connection tightness between adjacent frames, increase the contact area, improve the stability and wind pressure resistance of the structure; so that a mutual support and reinforcement effect is formed between the frames, greatly enhancing the structural strength of the entire insulation layer.

[0025] The beneficial effects of the present invention are as follows: the present invention realizes comprehensive application in tunnels by integrating the three functions of heat insulation, waterproofing and shock absorption; compared with the use of all polyphenolic foam materials, the present invention improves the compressive strength and waterproofing ability of the insulation layer by using silicate composite insulation roll felt and honeycomb structure; at the same time, by using silicate composite insulation roll felt to make a honeycomb skeleton and filling polyphenolic foam material in the through holes, the dead weight of the insulation layer is reduced, and the thermal conductivity of the insulation layer is further reduced; the present invention effectively improves the performance of the insulation layer and saves the cost by combining silicate composite insulation roll felt and honeycomb structure; compared with all silicate composite insulation roll felt, the honeycomb structure of the present invention can better disperse the load, and filling the polyphenolic foam material can fill the gap, close to the wall, and ensure the tightness and stability of the whole structure; the present invention also meets the requirements of tunnel energy absorption and shock absorption, so for tunnels with earthquake protection requirements, there is no need to set up an additional earthquake-proof layer, which reduces the construction complexity and cost and improves the efficiency and economy of engineering construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the laying method of the thermal insulation layer;

[0027] Figure 2 is the cross-section diagram of the thermal insulation layer;

[0028] Figure 3 Schematic diagram of the specific structure of the thermal insulation layer;

[0029] Among them: 1. Initial support; 2. Protective layer; 3. Insulation layer; 4. Silicate composite insulation roll felt layer; 5. Secondary lining; 6. Skeleton; 7. Filling layer; 8. Through hole. DETAILED DESCRIPTION

[0030] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0031] like Figure 1 to Figure 3As shown, this embodiment provides a new type of composite tunnel insulation layer. First, an initial support layer 1 is set on the outside of the tunnel surrounding rock, and its function is to provide support and protection in the initial stage of tunnel construction to ensure safety and stability during the construction process; a protective layer 2 is set on the outside of the initial support layer 1, and the protective layer 2 has certain waterproof and anti-seepage capabilities, which effectively isolates the contact between the external environment and the initial support layer 1; an insulation layer 3 is set on the outside of the protective layer 2, and its main function is to reduce the transfer of temperature inside and outside the tunnel structure and reduce the effect of heat conduction, thereby achieving the purpose of insulation; a silicate composite insulation roll felt layer is set on the outside of the insulation layer 3, and its main function is to enhance the insulation effect of the insulation layer 3 and further reduce heat transfer. The silicate composite insulation roll felt has good high temperature resistance and insulation performance, can effectively reduce the transfer of temperature inside and outside the tunnel, and improve the overall insulation effect; finally, a secondary lining 5 is set on the outside of the silicate composite insulation roll felt layer, and the secondary lining 5 mainly plays a role of reinforcement and protection, which can enhance the structural stability and durability of the entire insulation layer and ensure the long-term use effect of the insulation layer.

[0032] The laying method of the sandwich insulation layer 3 can effectively prevent heat from being directly transferred to the secondary lining 5, and effectively protect the secondary lining concrete. However, the insulation layer 3 needs to withstand a certain surrounding rock pressure and is more likely to absorb water than other methods, which can easily lead to a significant decrease in the insulation effect; therefore, the selected insulation layer 3 needs to meet certain compressive strength and waterproof capabilities.

[0033] In this embodiment, the heat insulating layer 3 includes a skeleton 6 and a filling layer 7. A plurality of hexagonal through holes 8 are arranged on the skeleton 6. The hexagonal through holes 8 are pressed by a hexagonal model. The through holes 8 are arranged in a honeycomb shape. The filling layer 7 is arranged in the through holes 8. The material of the filling layer 7 is a polyphenolic foam material. The material of the skeleton 6 is a silicate composite insulation roll felt with high compressive strength and good waterproof effect. The silicate composite insulation material is an excellent thermal insulation material with low thermal conductivity and high closed porosity. It can effectively reduce heat conduction and loss, provide good thermal insulation effect, help maintain the temperature difference between the inside and outside of the tunnel, and reduce energy consumption. The honeycomb structure can effectively reduce heat conduction. The continuous boundaries between the hexagonal units can form closed air cavities, which can block the path of heat conduction. In addition, the air pores in the honeycomb skeleton 6 can also reduce the influence of heat conduction and provide better thermal insulation effect.

[0034] On the other hand, each internal angle of the hexagon is 120 degrees, which means that inside the skeleton 6 of the entire insulation layer 3, each connection point can evenly distribute the load and pressure. This even distribution property is conducive to bearing a large amount of external force, reducing the concentration of local stress, and improving the overall strength and stability of the skeleton 6. Specifically, the side length of the bottom surface of the hexagonal prism through hole 8 is greater than the side edge of the hexagonal prism through hole 8, which can effectively increase the connection between the honeycomb structure units.

[0035] During construction, in order to ensure the stability and strength of the tunnel surrounding rock, initial support 1 construction is required.

[0036] After the construction of the initial support 1 is completed, the construction workers prepare a special anchoring glue, which has good adhesion and anti-penetration properties. The construction workers need to evenly apply the anchoring glue on the back of the skeleton 6 of the insulation layer 3 to improve the bonding strength between the anchoring glue and the honeycomb skeleton 6; the anchoring glue is the protective layer 2.

[0037] Next, the silicate composite insulation roll felt honeycomb skeleton 6 is attached to the primary lining concrete structure and compacted. The purpose of this step is to make the silicate composite insulation roll felt and the primary lining concrete structure tightly bonded together to increase the overall stability and strength.

[0038] Then, the silicate composite insulation roll felt is filled with polyphenolic foam material. The polyphenolic foam material has the characteristic of automatic high-temperature foaming, which can fill the gaps of the honeycomb skeleton 6, thereby increasing the insulation performance and stability of the tunnel surrounding rock.

[0039] Next, polyurethane glue is applied to the entire insulation roll felt, and it is attached to the honeycomb frame 6 and compacted. Polyurethane glue has the characteristics of strong bonding, high temperature resistance, and UV resistance, which can ensure the firm bonding between the insulation roll felt and the honeycomb frame 6 and improve the overall support effect. By applying polyurethane glue to the surface of the insulation roll felt to form a uniform protective layer 2, the durability and water resistance of the insulation roll felt can be improved, thereby protecting the insulation layer 3 from moisture, corrosion and other factors, and extending the service life.

[0040] Afterwards, the anti-cracking mortar needs to be prepared. The construction workers mix the glue powder, No. 425 cement, fine sand and accelerator evenly, and then apply it on the already laid silicate composite insulation roll felt insulation board. This can fill the defects on the surface of the insulation roll felt and increase the surface flatness and anti-cracking performance.

[0041] Finally, a mesh cloth is buried on the surface of the anti-crack mortar, and after the mesh cloth is dried to a non-sticky state, the concrete spraying of the secondary lining 5 is carried out. This step can further strengthen the construction site and ensure the long-term stability of the tunnel surrounding rock.

[0042] Under the premise of not changing the construction cost, compared with the method of laying silicate composite insulation roll felt throughout, the present invention chooses to adopt a silicate composite insulation roll felt honeycomb skeleton 6 and fills the honeycomb with polyphenolic foam material to achieve the effect of reducing the self-weight of the insulation layer 3 and reducing the thermal conductivity coefficient; the density range of the polyphenolic foam material is 41 to 100 kg / m3, which is relatively light and can reduce the weight of the overall insulation layer 3. This feature reduces the load and pressure of the overall structure and helps to improve the stability and durability of the structure.

[0043] The thermal conductivity of polyphenolic foam material ranges from 0.025 to 0.004, which is significantly lower than the thermal conductivity of silicate composite insulation roll felt, which ranges from 0.042 to 0.045. By using polyphenolic foam material to fill the honeycomb skeleton 6, the conduction of heat can be effectively reduced and the thermal insulation effect can be improved. This is of great significance for maintaining the temperature stability inside the tunnel; polyphenolic foam material has good plasticity and adhesion, can adapt to spaces of various shapes and sizes, and can be closely combined with other engineering materials to form a continuous thermal insulation layer 3, which can effectively prevent heat leakage and the generation of cold and hot bridges, and improve the overall thermal insulation effect.

[0044] The above embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in other forms. Any person skilled in the art may use the above disclosed technical contents to change or modify them into equivalent embodiments with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the technical solution of the present invention still falls within the protection scope of the present invention.

Claims

1. A new type of composite tunnel insulation layer, characterized in that: It includes an initial support (1), a protective layer (2), a thermal insulation layer (3), a silicate composite thermal insulation roll felt layer (4) and a secondary lining (5) which are arranged in sequence from the inside to the outside; The heat insulating layer (3) comprises a frame (6) and a filling layer (7); a plurality of hexagonal through holes (8) are arranged on the frame (6), the through holes (8) are arranged in a honeycomb shape, the filling layer (7) is arranged in the through holes (8), the material of the filling layer (7) is a polyphenolic foam material, and the material of the frame (6) is a silicate composite heat insulating rolled felt; The side length of the bottom surface of the hexagonal prism through hole (8) is greater than the side edge of the hexagonal prism through hole (8); The skeleton (6) is manufactured by pressing a silicate composite insulation roll felt into a honeycomb skeleton (6) using a hexagonal model; When laying the silicate composite thermal insulation felt layer (4), polyurethane glue is applied to the silicate composite thermal insulation felt, and the entire silicate composite thermal insulation felt is laid on the thermal insulation layer (3), compacted with force, and crack-resistant mortar is prepared by mixing glue powder, No. 425 cement, fine sand and a coagulant, and evenly applied to the silicate composite thermal insulation felt insulation board.

2. The construction method of the novel composite tunnel insulation layer according to claim 1 is characterized in that: The following steps are involved: S1, initial support (1) construction of surrounding rock; S2, constructing a heat insulation layer (3) on the outside of the initial support (1), and evenly coating a layer of anchoring glue on the back of the frame (6) of the heat insulation layer (3), wherein the anchoring glue is used as a protective layer (2); S3, attaching the frame (6) coated with anchoring glue to the initial support (1); S4, filling the through hole (8) of the frame (6) with polyphenolic foam material, allowing the polyphenolic foam material to automatically foam at high temperature to fill the gap of the through hole (8); S5, attaching a silicate composite thermal insulation felt roll layer (4), applying polyurethane glue on the silicate composite thermal insulation felt roll, attaching the entire silicate composite thermal insulation felt roll on the thermal insulation layer (3), compacting it firmly, mixing anti-cracking mortar with glue powder, No. 425 cement, fine sand and accelerator, and evenly applying it on the silicate composite thermal insulation felt roll insulation board; S6, carry out secondary lining (5) construction, bury mesh cloth on the outside of the silicate composite insulation roll felt layer (4), and cover the mesh cloth with sprayed concrete.

3. The construction method of the novel composite tunnel insulation layer according to claim 2 is characterized in that: The connection between the thermal insulation layer (3) and the primary support (1) and the secondary lining (5) is achieved by anchoring and bonding.

4. The novel composite tunnel insulation layer according to claim 1 is characterized in that: Two adjacent honeycomb frames (6) are connected via built-in connecting pieces, convex-concave connections or screw connections.

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