Subway tunnel vibration reduction structure and construction method thereof

Abstract

The present application relates to the technical field of metro tunnel train operation vibration influence on adjacent building (structure) governance, specifically to a metro tunnel vibration reduction structure and its construction method, comprising a first stress support layer, a composite vibration isolation layer and a second stress support layer arranged from outside to inside, the composite vibration isolation layer comprises an asphalt granular concrete layer, a geotextile layer and a spring rubber support; one end of the spring rubber support is anchored in the first stress support layer, the other end penetrates the asphalt granular concrete layer, the geotextile layer and the second stress support layer in turn, and is locked by a fastener; the first stress support layer is a combined support body composed of a steel arch grid and sprayed rubber concrete in the mine method construction, or a combined support body composed of rubber mortar and shield segment in the shield method construction; the second stress support layer is a steel plate with a plurality of honeycomb vibration absorption holes. The metro tunnel has a double-layer stress support system and a three-layer vibration isolation layer, and adopts a layered sandwich arrangement, so the vibration reduction and isolation effect is more significant.

Description

Technical Field

[0001] This invention relates to the field of technology for mitigating the impact of subway train operation vibration on adjacent buildings and structures, specifically to a subway tunnel vibration reduction structure and its construction method. Background Technology

[0002] Urban rail transit tunnels are generally constructed using mining methods and shield tunneling methods. Mining methods typically employ cast-in-place steel arch grate structures, where shotcrete is used for initial support at the tunnel face, followed by the erection of steel arch grate formwork and the casting of concrete for secondary support. Shield tunneling uses shield segments as the tunnel support structure, with grouting filling the gaps between the shield segments and the surrounding rock. Urban rail transit tunnels often pass under existing buildings or have residential or commercial office buildings built above subway stations. Due to the shallow burial depth of subway tunnels, the vibrations caused by train operation have a significant impact on the overlying buildings. Subway tunnel vibrations greatly reduce the comfort of residential use and affect the office environment, becoming an environmental hazard that is increasingly attracting the attention of construction and operation units. Environmental assessments are now necessary during the design phase, and measures to control and reduce vibrations must be incorporated into the tunnel design scheme.

[0003] For example, Chinese patent application CN104695974A discloses a vibration reduction method and structure for underground rail transit engineering, which uses different types of rubber or chemical materials to make vibration damping pads and wraps them around the outside of the tunnel segments. Its advantage is its simple structure and ease of implementation, but it does not consider the aging problem of the rubber pads under vibration and groundwater. Chinese patent application CN104847384A discloses a method for vibration reduction and noise reduction in subway tunnels, which involves injecting vibration damping grout into the outside of the tunnel segments below the track surface and setting rubber concrete on the inside of the tunnel segments above the track surface, but it does not disclose the components of the injected vibration damping grout and the rubber concrete. Chinese patent application CN110030020A... The first application discloses a vibration reduction and noise reduction structure and construction method for subway tunnels, including a circular tunnel lining, a rectangular tunnel, and a bridge-type support structure supporting the rectangular tunnel. The rectangular tunnel is a vacuum space in which trains run. Vibration-damping rubber pads are placed on the top surface of the bridge-type support. The double-tunnel structure and bridge-type support not only more than double the cost, but also make it infeasible for personnel to enter and exit the station due to the vacuum in which trains run. The second application, Chinese patent application CN110851894A, discloses a vibration-damping rubber-spring coupling structure and its design method for subway tunnels. This rubber-spring coupling structure is placed between a steel arch and the soil layer, and is in direct contact with water and soil, leading to rubber aging and spring corrosion problems. Furthermore, existing vibration reduction methods share a common drawback: the vibration-damping structure is single-layered, resulting in limited vibration reduction effectiveness. Summary of the Invention

[0004] To address the problems mentioned above, this invention provides a vibration reduction structure for subway tunnels and its construction method. The subway tunnel cross-section is designed as a multi-layered sandwich-type distributed load-bearing support system and vibration isolation layer. The construction method can be used for vibration reduction and isolation treatment of newly built subway tunnels, as well as for adding vibration isolation layers to existing tunnels. The construction is quick and the vibration reduction and isolation effect is significant.

[0005] The first aspect of the present invention is to provide a vibration reduction structure for a subway tunnel, comprising a first load-bearing support layer, a composite vibration isolation layer, and a second load-bearing support layer arranged sequentially from the outside to the inside, wherein:

[0006] The composite vibration isolation layer includes an asphalt aggregate concrete layer and a geotextile layer. The asphalt aggregate concrete layer is adjacent to the inner side of the first load-bearing support layer, and the geotextile layer is disposed between the asphalt aggregate concrete layer and the second load-bearing support layer.

[0007] The composite vibration isolation layer is also equipped with spring rubber bearings; the first end of the spring rubber bearing is anchored in the first load-bearing support layer, and the second end passes through the through hole in the asphalt aggregate concrete layer, the geotextile layer and the second load-bearing support layer in sequence, and is locked to the second load-bearing support layer by fasteners.

[0008] The first load-bearing support layer is a combined support structure consisting of steel arch grid and sprayed rubber concrete in mining construction, or a combined support structure consisting of rubber mortar and shield segments in shield tunneling construction.

[0009] The second load-bearing support layer is a steel plate with several honeycomb vibration-absorbing holes circumferentially opened.

[0010] Furthermore, when the first load-bearing support layer is a combined support structure consisting of a steel arch grid and sprayed rubber concrete, a ring of steel arch grid is processed into at least two sections, and adjacent sections of the steel arch grid are connected by friction deformation connectors, forming a steel arch grid deformation joint that is narrow at the top and wide at the bottom at the connection.

[0011] The friction deformation connector is sleeved on the outer periphery of the steel arch grid, and the contact surface between the friction deformation connector and the steel arch grid is provided with grooves to increase friction.

[0012] Furthermore, the spring rubber support includes a cylindrical rubber and a spring embedded in the cylindrical rubber. The cylindrical rubber is embedded in the asphalt granulated concrete layer, and its height is the same as the thickness of the asphalt granulated concrete layer.

[0013] The first end of the spring forms a pre-embedded anchoring section, which extends out of the cylindrical rubber and is anchored in the first stress-bearing support layer.

[0014] The second end of the spring forms a threaded connection section, which passes through the geotextile layer and the second load-bearing support layer in sequence, and is then locked to the second load-bearing support layer by a nut.

[0015] Furthermore, the raw materials for the asphalt aggregate concrete layer include: asphalt aggregate, cement, coarse aggregate, fine aggregate, medium sand, mineral powder, and water-reducing agent;

[0016] Among them, the particle size of asphalt particles is no greater than 10mm, and their mass accounts for 5%-7% of the total mass of aggregate;

[0017] The mass of mineral powder accounts for 1%-3% of the total mass of aggregate;

[0018] The mass ratio of cement, medium sand and gravel is 1:(1.1-2.3):(2.7-3.3).

[0019] Furthermore, the raw materials for rubber mortar include: rubber granules, cement, medium sand, fly ash, bentonite, and water-reducing agent;

[0020] Rubber granules are particles made from crushed waste tires, accounting for 10%-15% of the total mass of rubber mortar; cement accounts for 20%-25% of the total mass of rubber mortar, and bentonite accounts for 3%-5% of the total mass of rubber mortar.

[0021] Furthermore, the raw materials for shotcrete include: rubber granules, fine aggregate, medium sand, cement, bentonite, and quick-setting agent;

[0022] Rubber granules are made from crushed waste tires, with a particle size of 0-2.5mm, and their mass accounts for 10%-15% of the total aggregate mass; fine stones are pebbles or crushed stone with a particle size ≤15mm and a mud content ≤1%.

[0023] Cement accounts for 25%-30% of the total aggregate mass, and bentonite accounts for 3%-5% of the total aggregate mass.

[0024] A second aspect of the present invention is to provide a construction method for a vibration reduction structure for a subway tunnel, comprising the following steps:

[0025] S1: For mining tunnels, friction deformation connectors are used to connect steel arch grids at the rough cross-section, and then rubber concrete is sprayed to form the first load-bearing support layer; for shield tunnels, after several rings of shield segments are installed, rubber mortar is injected through tail grouting to form the first load-bearing support layer.

[0026] S2: Divide the steel plate installation units along the tunnel axis at intervals of 1.0m-2.0m. Each ring installation unit is divided into multiple installation blocks. Number the installation blocks at different positions, cut the steel plates according to the design dimensions, drill anchoring through holes and honeycomb vibration absorption holes on the steel plates, and bend the steel plates into an arc shape concentric with the tunnel.

[0027] S3: Transport the processed steel plates, asphalt aggregate concrete, first feeding hopper, second feeding hopper, side formwork, vibrating rod, vibrating hammer, and air compressor to the tunnel working face;

[0028] S4: Drill holes at the anchorage positions of the first load-bearing support layer using an impact drill, with a depth equal to the anchorage depth of the spring rubber support. Use a compressed air pipe to blow away the ash and slag in the holes, inject structural anchoring adhesive, and insert the spring rubber support into the anchorage holes.

[0029] S5: First, use the robotic arm to grab the bottom plate and place it in the predetermined position. Adjust and accurately position it so that the threaded spring tail of the spring rubber support passes through the anchoring through hole. Tighten the nut to anchor the steel plate. The gap between the steel plate and the first load-bearing support layer is not less than 50mm. Then install other mounting blocks. The installation sequence of the mounting blocks is bottom plate, side wall block, and top block. The joints of adjacent mounting blocks are welded together.

[0030] S6: Seal the side formwork of the cavity between the two ends of the steel plate of the first ring installation unit and the first load-bearing support layer, pour asphalt aggregate concrete, and remove the side formwork after the asphalt aggregate concrete has hardened.

[0031] S7: Repeat steps S4 to S6 to complete the construction of all tunnel vibration reduction structures.

[0032] Furthermore, in step S2: the steel plate of the tunnel ring installation unit is divided into 6-9 installation blocks, 2-3 sidewall blocks for each of the two tunnel arch waists, 1 bottom plate and 1 top plate, with the bottom plate having the largest arc angle, the sidewall blocks having the second largest arc angle, and the top plate having the smallest arc angle; the geotextile is glued to the steel plate with structural adhesive.

[0033] Furthermore, in step S6: a first feeding hopper is set on each of the two arch waists of each ring steel plate, a second feeding hopper is set on the top block, and at least one exhaust pipe is set on the steel plate of each ring installation unit.

[0034] First, asphalt aggregate concrete is fed from the first feeding hopper. Inside the tunnel, a vibratory hammer is used to repeatedly beat the steel plate to make the asphalt aggregate concrete dense and free of voids. At the same time, a vibrating rod is inserted through the first feeding hopper to compact the asphalt aggregate concrete and seal the first feeding hopper. Then, asphalt aggregate concrete is fed from the second feeding hopper and vibrated to make it dense. During the feeding and vibration process, the exhaust pipe is used to vent the air.

[0035] Furthermore, in step S6: the vibratory hammer is powered by compressed air supplied by an air compressor, the air compressor is connected to a compressed air pipe, and a compressed air pipe connector and a compressed air pipe valve are installed on the compressed air pipe;

[0036] The vibratory hammer is operated by hand. A self-locking valve is installed on the handle of the vibratory hammer. When the finger is pressed against the self-locking valve, the self-locking valve opens, and compressed air is ejected through the air jet of the vibratory hammer. The vibratory hammer vibrates in close contact with the steel plate, making the asphalt concrete compacted.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] (1) The vibration reduction structure of the subway tunnel of the present invention integrates a double-layer force-bearing system and a triple vibration isolation layer. Its double-layer force-bearing system includes a first force-bearing support layer and a second force-bearing support layer; the triple vibration isolation layer integrates sprayed rubber concrete / rubber mortar, asphalt granular concrete layer and spring rubber support, as well as steel plate with honeycomb vibration-absorbing holes and geotextile, thereby achieving a very significant vibration reduction effect.

[0039] (2) The spring rubber support of the present invention utilizes a composite design of a cylindrical rubber-wrapped spring to achieve better vibration reduction effect. The spring, as the core elastic element, can effectively isolate low- and medium-frequency vibrations and provide support; while the rubber wrapped around it significantly increases the system damping, converting vibration energy into heat energy for consumption. At the same time, the cylindrical rubber wrapping around the spring forms a sealed protective layer, which can isolate the humid and corrosive environment in the tunnel, effectively prevent the spring from rusting, and significantly extend the service life of the vibration reduction structure.

[0040] (3) The asphalt particles in the asphalt granule concrete of the present invention are made by crushing asphalt blocks in a solidified state by a crusher at room temperature and adding them to the concrete as admixtures and mixing them evenly to make premixed concrete. Compared with asphalt concrete mixed by high temperature hot melting, it is more suitable for tunnel construction. The asphalt particles in the asphalt granule concrete layer play a role in improving compressibility and absorbing vibration.

[0041] (4) The rubber particles in the rubber mortar and sprayed rubber concrete of the present invention are all made from waste tires by machine crushing and processing, realizing the efficient resource utilization of solid waste and reducing material costs. At the same time, the addition of rubber particles transforms rigid mortar into flexible composite material, achieving the effect of vibration reduction. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 A cross-sectional view of the vibration reduction structure and vibration isolation layer for a subway mining tunnel provided in an embodiment of the present invention;

[0044] Figure 2 A cross-sectional view of the vibration reduction and isolation layer of a subway shield tunnel provided in an embodiment of the present invention;

[0045] Figure 3 A detailed drawing of a friction deformation connector for subway mining tunnels provided in one embodiment of the present invention;

[0046] Figure 4 An unfolded view of a ring steel plate mounting unit and a spring rubber support provided in an embodiment of the present invention;

[0047] Figure 5 A longitudinal section view of a spring rubber bearing and an asphalt granular concrete layer provided in an embodiment of the present invention;

[0048] Figure 6 A cross-sectional view of the installation of the segmented steel plate and the spring rubber support provided in an embodiment of the present invention;

[0049] Figure 7 A schematic diagram of a spring rubber support provided in an embodiment of the present invention;

[0050] Figure 8 A cross-sectional view of asphalt granular concrete feeding provided in an embodiment of the present invention;

[0051] Figure 9 A longitudinal cross-sectional view of asphalt aggregate concrete feeding provided in an embodiment of the present invention;

[0052] Figure 10 A longitudinal cross-sectional view of asphalt-granular concrete under vibration provided in an embodiment of the present invention;

[0053] Figure 11 A schematic diagram of a vibratory hammer provided in an embodiment of the present invention;

[0054] Figure 12 One embodiment of the present invention provides a schematic diagram of a compressed air self-locking valve;

[0055] The components include: 1. Steel arch girder; 11. Shield tunnel segment; 101. Shotcrete; 110. Rubber mortar; 102. Anchor hole; 103. Friction deformation connector; 104. Steel arch girder expansion joint; 2. Steel plate; 201. Honeycomb vibration absorption hole; 202. Geotextile layer; 203. Anchoring through hole; 204. Nut; 301. First feeding hopper; 302. Second feeding hopper; 4. Exhaust pipe; 5. Side formwork; 6. Asphalt granular concrete layer; 7. Spring rubber support; 701. Cylindrical rubber; 702. Spring; 7021. Pre-embedded anchoring section; 7022. Threaded connection section; 8. Vibrating rod; 9. Vibrating hammer; 901. Self-locking valve; 902. Handle; 903. Air jet hole; 904. Compressed air pipe joint; 10. Air compressor; 1001. Compressed air pipe; 1002. Compressed air pipe valve. Detailed Implementation

[0056] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0057] The following is in conjunction with the appendix Figure 1 To be continued Figure 12 The invention is described in detail with specific embodiments.

[0058] First, it should be noted that the directional terms "inner" and "outer" used in this application should be understood as follows: with reference to the tunnel axis, "inner" refers to the direction closer to the axis, and "outer" refers to the direction farther from the axis.

[0059] See Figures 1 to 12 This application provides a vibration reduction structure for a subway tunnel, comprising a first load-bearing support layer, a composite vibration isolation layer, and a second load-bearing support layer arranged sequentially from the outside to the inside. The composite vibration isolation layer includes an asphalt aggregate concrete layer 6 and a geotextile layer 202. The asphalt aggregate concrete layer 6 is adjacent to the inner side of the first load-bearing support layer, and the geotextile layer 202 is disposed between the asphalt aggregate concrete layer 6 and the second load-bearing support layer. A spring rubber support 7 is also provided within the composite vibration isolation layer. The first end of the spring rubber support 7 is anchored within the first load-bearing support layer, and the second end sequentially penetrates the asphalt aggregate concrete layer 6, the geotextile layer 202, and the anchoring through-hole 203 on the second load-bearing support layer, and is finally locked to the second load-bearing support layer by fasteners. The first load-bearing support layer in this application is specifically defined as: in mining construction (such as... Figure 1 As shown), the first load-bearing support layer is a combined support structure composed of steel arch grating 1 and sprayed rubber concrete 101, or in shield tunneling construction (such as...). Figure 2 As shown in the figure, the first load-bearing support layer is a combined support structure composed of rubber mortar 110 and shield tunnel segments 11; the second load-bearing support layer is a steel plate 2 with several honeycomb vibration-absorbing holes in the circumferential direction.

[0060] The vibration reduction structure for subway tunnels in this application integrates a double-layer load-bearing system and a triple vibration isolation layer. On one hand, the double-layer load-bearing system includes a first load-bearing support layer and a second load-bearing support layer. The first load-bearing support layer provides strong initial support stiffness and has two configuration forms, adapted to both mining and shield tunneling methods. The second load-bearing support layer is a steel plate 2, with honeycomb vibration-absorbing holes 201 on it, giving it the dual function of support and dissipating vibration energy through the holes. On the other hand, the triple vibration isolation layer consists of a first vibration isolation layer composed of sprayed rubber concrete 101 / rubber mortar 110, a second vibration isolation layer composed of an asphalt aggregate concrete layer 6 and spring rubber bearings 7, and a third vibration-absorbing layer composed of honeycomb vibration-absorbing holes 201 on the steel plate 2 and a geotextile layer 202. Through the design of the above structure, a highly significant vibration reduction effect is achieved.

[0061] For details, please refer to Figure 1 , Figure 3 When the first load-bearing support layer is a combined support structure consisting of a steel arch grid 1 and sprayed rubber concrete 101, i.e., during mining construction, the steel arch grid 1 is first installed on the rough cross-section of the tunnel. A single ring of steel arch grid 1 is typically processed into two sections, and adjacent sections of the steel arch grid 1 are connected by a friction deformation connector 103, forming a steel arch grid deformation joint 104 that is narrower at the top and wider at the bottom. The friction deformation connector 103 is fitted around the outer periphery of the steel arch grid 1, and the contact surface between the friction deformation connector 103 and the steel arch grid 1 has grooves to increase friction, effectively enhancing the friction between the contact surfaces. After the steel arch grid 1 is installed, sprayed rubber concrete is applied. The steel arch grid 1 with the friction deformation connector 103 and the sprayed rubber concrete 101 have the ability to absorb vibration deformation. More specifically, the friction deformation connector 103 designed in this application, combined with the narrower-at-the-top-wider-at-the-bottom steel arch grid deformation joint 104, provides a pre-set, controllable deformation interface for the support structure. This design not only enhances the support system's adaptability to geological conditions, but also allows for limited, non-destructive relative sliding or displacement at the connection points when minor displacements occur in the surrounding rock or soil. This effectively releases some of the surrounding rock stress and significantly reduces the risk of concrete cracking or steel arch buckling caused by stress concentration. Furthermore, under vibration or external loads, the grooves on the contact surface of the friction deformation connector 103 can convert some vibration energy into heat energy and dissipate it through a friction energy dissipation mechanism, thereby effectively suppressing structural vibration.

[0062] Specifically, in the construction of subway tunnels using the mining method, the first load-bearing support layer, composed of steel arch grating 1 and sprayed rubber concrete 101, essentially constitutes the initial lining of the subway tunnel. During construction, steel arch grating 1 is first laid out along the tunnel axis at intervals of 0.5m-1.0m, with each steel arch grating 1 precisely positioned. Similarly, a ring of steel plates 2 is also installed sequentially along the tunnel axis. Through this process, the initial lining of the subway tunnel and the steel plates 2 together form a complete double-layer load-bearing support system. Between this double-layer load-bearing support system, a composite vibration isolation layer composed of asphalt aggregate concrete layer 6 and spring rubber bearings 7 is set. This composite vibration isolation layer not only serves as a connection and force transmission layer, but also effectively attenuates and isolates the transmission of vibration waves in the structure through the damping characteristics of its materials and the elastic support of its components.

[0063] For details, please refer to Figures 4 to 7 In mining or shield tunneling construction, the spring rubber bearing 7 includes a cylindrical rubber 701 and a spring 702 embedded within the cylindrical rubber 701. The cylindrical rubber 701 is embedded in the asphalt granulated concrete layer 6, and its height is designed to match the thickness of the asphalt granulated concrete layer 6. The first end of the spring 702 forms a pre-embedded anchoring section 7021, which extends out of the cylindrical rubber 701 and is firmly anchored within the first load-bearing support layer. The second end of the spring 702 forms a threaded connection section 7022, which passes sequentially through the geotextile layer 202 and the second load-bearing support layer (i.e., steel plate 2), and is then locked to the second load-bearing support layer (i.e., steel plate 2) by a nut 204. More specifically, the key dimensional parameters of the spring 702 are as follows: the diameter of the spring 702 is between 10mm and 20mm, and the diameter of the cylindrical rubber 701 encasing it is between 50mm and 100mm. The cylindrical rubber 701 encases the spring 702, effectively isolating it from the environmental medium and preventing corrosion. Furthermore, its high damping characteristics significantly enhance the overall damping performance and energy dissipation capacity of the spring rubber support 7. The length of the pre-embedded anchorage section 7021 of the spring 702 matches the depth of the anchorage hole 102 in the first load-bearing support layer. The anchorage depth of the pre-embedded anchorage section 7021 is not less than five times the spring diameter, ensuring the spring rubber support 7 is reliably anchored in the shield tunnel segment 11 or shotcrete 101, guaranteeing the stability of the root of the spring rubber support 7 under vibration loads. The second end of the spring 702 serves as a threaded connection section 7022, which passes through all structural layers and is then locked to the steel plate 2 with a nut 204. This design allows a controllable preload to be applied to the entire double-layer support system during construction, making the connection between the layers tighter, eliminating initial gaps, and improving overall stiffness. Furthermore, the spring 702 mechanically connects the first load-bearing support layer, the composite vibration isolation layer, and the second load-bearing support layer into a whole, establishing a clear and efficient force transmission chain, which makes the stability and reliability of the entire vibration reduction structure better.

[0064] Furthermore, see Figure 7 The spring-rubber bearing 7 of this application adopts a composite design of a cylindrical rubber 701 encasing a spring 702, achieving better vibration reduction. The spring 702, as the core elastic element, effectively isolates vibration and provides stable support for the entire double-layer support system. The cylindrical rubber 701, encasing the spring 702, plays a crucial role as a damping material. Through its viscoelastic deformation, it efficiently converts and dissipates the mechanical energy of vibration into heat energy. Simultaneously, the cylindrical rubber 701 encasing the spring 702 forms a sealed protective layer, isolating the spring 702 from the humid and corrosive environment within the tunnel, effectively preventing corrosion and significantly extending the service life of the vibration reduction structure. Furthermore, its dimensions have been optimized, balancing the requirements of load-bearing strength and damping within a limited space, significantly improving the vibration reduction effect.

[0065] In some embodiments, the raw materials of the asphalt aggregate concrete layer 6 include: asphalt aggregate, 425 grade silicate cement, coarse aggregate, fine aggregate, medium sand, mineral powder, and water-reducing agent; wherein, the asphalt aggregate is formed by crushing asphalt blocks in a solidified state at room temperature by a crusher, the particle size of the asphalt aggregate is not greater than 10 mm, and it is added to the concrete as an admixture and mixed evenly, and its mass accounts for 5%-7% of the total aggregate mass. The asphalt aggregate in the asphalt aggregate concrete layer plays a role in improving compressibility and absorbing vibration. Specifically, the asphalt aggregate dispersed in the matrix, as a highly damping flexible phase, can generate significant viscoelastic deformation when subjected to cyclic loads, converting mechanical energy into heat energy and dissipating it; the mineral powder accounts for 1%-3% of the total aggregate mass. The mineral powder can effectively fill the micropores between cement, sand, and stone, greatly improve the density of the matrix, and reduce the possibility of vibration energy being reflected and amplified between pores; the mass ratio of cement, medium sand, and stone is 1:(1.1-2.3):(2.7-3.3). The above ratio provides a solid rigid support foundation for the concrete skeleton.

[0066] In some embodiments, the raw materials of the rubber mortar 110 used in shield tunneling include: rubber granules, cement, medium sand, fly ash, bentonite, and a water-reducing agent. The rubber granules are particles obtained by crushing waste tires by machine, with a particle size of 0-2.5mm. They are mixed evenly into the mortar and account for 10%-15% of the total mass of the rubber mortar. Firstly, the use of rubber granules realizes the efficient resource utilization of solid waste and reduces material costs. Secondly, the addition of rubber granules transforms rigid mortar into a flexible composite material, achieving a vibration reduction effect. The cement accounts for 20%-25% of the total mass of the rubber mortar, providing the necessary structural strength. The bentonite accounts for 3%-5% of the total mass of the rubber mortar. The excellent water retention and thickening effect of bentonite effectively improves the problem of decreased workability that may be caused by the addition of rubber granules, ensuring that the mortar has good flow uniformity, stability, and anti-segregation properties during shield grouting, thus guaranteeing construction quality and the filling density of the voids behind the shield.

[0067] In some embodiments, the raw materials for the shotcrete 101 constructed using the mining method include: rubber granules, fine aggregate, medium sand, cement, bentonite, and a quick-setting agent. The rubber granules are particles obtained from crushed waste tires, with a particle size of 0-2.5 mm. They are mixed evenly with fine aggregate, medium sand, cement, and bentonite, and then mixed with water when sprayed using a shotcrete machine. The rubber granules account for 10%-15% of the total aggregate mass. The evenly distributed rubber granules form a large number of elastic nodes inside the concrete, significantly improving the flexibility and deformation capacity of the material. The fine aggregate is pebbles or crushed stone with a particle size ≤15 mm and a mud content ≤1%. The cement mass accounts for 25%-30% of the total aggregate mass, and the bentonite mass accounts for 3%-5% of the total aggregate mass. The above proportions make the compressibility of the shotcrete more than twice that of ordinary shotcrete.

[0068] See Figures 8 to 10 The present invention also provides a construction method for a vibration reduction structure for a subway tunnel, wherein the subway tunnel in the protected area is divided into several installation units, and the aforementioned vibration reduction structure is fabricated on each installation unit. The construction method includes the following steps:

[0069] S1: For mining tunnels, the steel arch grid 1 is connected by friction deformation connector 103 at the rough cross-section, and then rubber concrete 101 is sprayed to form the first load-bearing support layer; for shield tunnels, after the shield segments 11 are installed in several rings, rubber mortar 110 is injected by grouting at the shield tail to form the first load-bearing support layer.

[0070] S2: Divide the steel plate installation units along the tunnel axis at intervals of 1.0m-2.0m. Each ring installation unit is divided into multiple installation blocks. Number the installation blocks at different positions. Cut the steel plate 2 according to the design dimensions and drill anchoring through holes 203 and honeycomb vibration absorption holes 201 on the steel plate 2. Bend the steel plate 2 into an arc shape concentric with the tunnel.

[0071] S3: Transport the processed steel plate 2, asphalt aggregate concrete, first feeding hopper 301, second feeding hopper 302, side formwork 5, vibrating rod 8, vibrating hammer 9, and air compressor 10 to the tunnel working face.

[0072] S4: Drill holes at the anchoring holes 102 of the first load-bearing support layer using an impact drill, with a depth equal to the anchoring depth of the spring rubber support 7. Use a compressed air pipe 1001 to blow away the ash and slag in the holes, inject structural anchoring adhesive, and insert the spring rubber support 7 into the anchoring holes 102. The spring rubber support 7 of this application includes a cylindrical rubber 701 and a spring 702 embedded in the cylindrical rubber 701, and both ends of the spring 702 extend out of the axial ends of the cylindrical rubber 701.

[0073] S5: First, use the robotic arm to grab the bottom plate and place it in the predetermined position. Adjust and accurately position it so that the threaded connection section 7022 of the spring rubber support 7 passes through the anchoring through hole 203. Tighten the nut 204 to anchor the steel plate 2. The gap between the steel plate 2 and the first load-bearing support layer is not less than 50mm, preferably 50mm-100mm. Then install other mounting blocks. The installation sequence of the mounting blocks is bottom plate, side wall block, and top block. The joints of adjacent mounting blocks are welded together with welding rods.

[0074] S6: Seal the cavity between the two ends of the steel plate 2 of the first ring installation unit and the first load-bearing support layer with the side formwork 5, pour asphalt aggregate concrete, and remove the side formwork 5 after the asphalt aggregate concrete has hardened.

[0075] S7: Repeat steps S4-S6 to complete the construction of all tunnel vibration reduction structures.

[0076] The above construction method utilizes spring rubber bearings 7 to achieve bidirectional connection and, combined with on-site casting, forms a complete composite structure, ensuring overall stability and effective load transfer. Simultaneously, the processes of pre-reserved gaps for pouring asphalt aggregate concrete and welding joints ensure the uniformity of the damping layer thickness and the continuity of the structure. The advantages of using spring rubber bearings 7 are as described in the section on damping structures and will not be repeated here.

[0077] Furthermore, in step S2: the steel plate 2 of the tunnel ring installation unit is divided into 6-9 installation blocks, 2-3 sidewall blocks for each of the two tunnel arch waists, and 1 bottom plate and 1 top plate. The bottom plate has the largest arc angle, followed by the sidewall blocks, and the top plate has the smallest arc angle. This design significantly reduces the difficulty of hoisting, positioning and splicing each component in the narrow tunnel space, and greatly improves the feasibility and efficiency of on-site construction. When installing the steel plate, the geotextile is simultaneously glued to the inner surface of the steel plate with structural adhesive. The geotextile, as a flexible interlayer, works with the honeycomb vibration-absorbing holes on the steel plate to further absorb and disperse vibration energy.

[0078] For further details, please refer to [link / reference]. Figure 9In step S6: After the side formwork 5 is closed at both ends of the steel plate 2 of the ring installation unit, a first feeding hopper 301 is set at each of the two arch waists of each ring steel plate 2, and a second feeding hopper 302 is set at the top block. At least one exhaust pipe 4 is set at the steel plate 2 of each ring installation unit. Asphalt aggregate concrete is first fed from the first feeding hopper 301. In the tunnel, a vibratory hammer 9 is used to repeatedly vibrate the steel plate 2 to make the asphalt aggregate concrete dense and free of voids. At the same time, a vibrating rod 8 is inserted through the first feeding hopper 301 to compact the asphalt aggregate concrete and close the first feeding hopper 301. Then, asphalt aggregate concrete is fed from the second feeding hopper 302 and vibrated to compact it. During the feeding and vibration process, the exhaust pipe 4 is used to vent the air. After the asphalt aggregate concrete hardens, the side formwork 5 is removed. By setting the first feeding hopper 301 at the two arch waists and the second feeding hopper 302 at the top block for segmented and orderly feeding, it conforms to the fluid mechanics characteristics of concrete and can effectively avoid segregation and blockage that may occur from one-time feeding. By combining external vibration with internal compaction with internal tamping with vibratory rod 8, the process effectively eliminates blind spots and voids during pouring, ensuring a tight bond between the asphalt aggregate concrete, steel plate 2, geotextile layer 202, and spring rubber support 7. This forms a uniform, continuous, and highly intact composite vibration isolation layer, guaranteeing the full realization of its design mechanical and vibration reduction performance. Simultaneously, during material feeding and vibration, the specially designed exhaust pipe 4 promptly and smoothly removes entrained air, effectively preventing the formation of defects such as air pockets and honeycomb. This significantly improves the density and strength of the asphalt aggregate concrete itself and reduces internal stress concentration points, thereby enhancing the durability and stability of the composite layer under long-term dynamic loads.

[0079] For further details, please refer to [link / reference]. Figure 11 and Figure 12 In step S6: the vibratory hammer 9 is powered by compressed air supplied by the air compressor 10. The air compressor 10 is connected to the compressed air pipe 1001. The compressed air pipe 1001 is equipped with a compressed air pipe connector 904 and a compressed air pipe valve 1002. The vibratory hammer 9 is operated by hand. The handle of the vibratory hammer 9 is equipped with a self-locking valve 901. When the finger holds the self-locking valve 901, the self-locking valve 901 opens, and compressed air is ejected through the air jet hole 903 of the vibratory hammer 9. The vibratory hammer 9 vibrates in close contact with the steel plate 2, so that the asphalt granular concrete is compacted.

[0080] In some cases, for existing tunnels, a vibration isolation layer can be constructed by adding steel plates 2 with honeycomb vibration-absorbing holes 201 and asphalt-aggregate concrete inside the steel arch grating 1 and shield segments 11. That is, the first load-bearing support layer of the existing tunnel has been completed, and the vibration isolation layer and the second load-bearing support layer are constructed on this basis. The specific construction steps are as follows: 1. Divide the steel plates of the tunnel's first ring installation unit into 6-9 installation blocks, 2-3 sidewall blocks for each of the two arch waists of the tunnel, and 1 bottom plate and 1 capping block. Furthermore, the bottom plate has the largest arc angle, followed by the side wall blocks, and the top plate has the smallest arc angle to reduce installation difficulty; 2. Cut steel plates 2 according to the design dimensions for installation blocks with different numbers, drill anchoring through holes 203 and honeycomb vibration absorption holes 201 on the steel plates 2, bend the steel plates 2 into an arc shape concentric with the tunnel, and use structural adhesive to attach the geotextile layer 202 to the steel plates 2; 3. Set a first feeding hopper 301 at each of the two arch waists of each ring of steel plates 2, and set a second feeding hopper 302 at the top plate, forming one ring installation unit. At least one exhaust pipe 4 is provided on the steel plate 2; firstly, asphalt aggregate concrete is fed from the first feeding hopper 301, and the steel plate 2 is repeatedly vibrated with a vibrating hammer 9 inside the tunnel to make the asphalt aggregate concrete dense and free of voids. At the same time, a vibrating rod 8 is inserted through the first feeding hopper 301 to compact the asphalt aggregate concrete, and the first feeding hopper 301 is sealed; then, asphalt aggregate concrete is fed from the second feeding hopper 302 and vibrated to compact it. During the feeding and vibration process, exhaust is provided by the exhaust pipe 4; 4. The vibrating hammer 9 passes through the air... The air compressor 10 provides compressed air as power. The air compressor 10 is connected to the compressed air pipe 1001. The compressed air pipe 1001 is equipped with a compressed air pipe connector 904 and a compressed air pipe valve 1002. The vibratory hammer 9 is operated by hand. The handle of the vibratory hammer 9 is equipped with a self-locking valve 901. When the finger holds the self-locking valve 901, the self-locking valve 901 opens, and compressed air is ejected through the jet hole 903 of the vibratory hammer 9. The vibratory hammer 9 vibrates in close contact with the steel plate 2, so that the asphalt granular concrete is compacted.

[0081] The present invention has been further described above with reference to specific embodiments. However, it should be understood that the specific description herein should not be construed as limiting the nature and scope of the present invention. Various modifications made to the above embodiments by those skilled in the art after reading this specification are all within the scope of protection of the present invention.

Claims

1. A construction method of a subway tunnel vibration reduction structure, characterized by, The construction method comprises the following steps: S1: for a mine tunnel, a friction deformation connector is used to connect a steel arch grid to a rough section, and then rubber concrete is sprayed to form a first force support layer; for a shield tunnel, after a shield segment is installed for several rings, rubber mortar is poured through shield tail grouting to form a first force support layer; S2: a steel plate installation unit is divided along the axis direction of the tunnel at an interval of 1.0-2.0 m, a ring installation unit is divided into a plurality of installation blocks, the installation blocks at different positions are numbered, the steel plate is cut according to the design size, and anchor through holes and honeycomb vibration holes are drilled on the steel plate, and the steel plate is bent into a circular arc shape concentric with the tunnel; S3: the processed steel plate, asphalt granular concrete, first feeding hopper, second feeding hopper, side formwork, vibrating rod, vibrating hammer, and air compressor are transported to the tunnel working face; S4: a drill is used to drill a hole at the anchor hole position of the first force support layer, the depth is equal to the anchor depth of the spring rubber support, a compressed air pipe is used to blow the hole clean, structural adhesive is poured, and the spring rubber support is inserted into the anchor hole; S5: a mechanical arm is used to first pick up the bottom plate block and place it at the predetermined position, the position is adjusted and accurately positioned, the threaded spring tail of the spring rubber support is passed out of the anchor through hole, the nut is tightened to anchor the steel plate, and the gap between the steel plate and the first force support layer is not less than 50 mm; then other installation blocks are installed, the installation sequence of the installation blocks is bottom plate block, side wall block, and top sealing block in turn, and the joints between adjacent installation blocks are welded into one body; S6: the cavities between the two end side surfaces of the steel plate of a ring installation unit and the first force support layer are closed by the side formwork, the asphalt granular concrete is poured, and the side formwork is removed after the asphalt granular concrete hardens; one first feeding hopper is arranged at each of the two haunches of the steel plate of a ring, the top sealing block is provided with a second feeding hopper, and at least one exhaust pipe is arranged for the steel plate of a ring installation unit; The asphalt granular concrete is first conveyed from the first feeding hopper, the vibrating hammer is repeatedly used to vibrate the steel plate in the tunnel to make the asphalt granular concrete dense and free of voids, the vibrating rod is inserted into the first feeding hopper, the vibrating rod is used to compact the asphalt granular concrete, and the first feeding hopper is closed; the asphalt granular concrete is then conveyed from the second feeding hopper, and is vibrated and compacted, and exhaust is performed through the exhaust pipe during the conveying and vibrating processes; S7: steps S4 to S6 are repeated to complete the construction of the entire tunnel vibration reduction structure; The subway tunnel vibration reduction structure formed by the construction method comprises a first force support layer, a composite vibration isolation layer, and a second force support layer arranged in turn from the outside to the inside, wherein: The composite vibration isolation layer comprises an asphalt granular concrete layer and a geotextile layer, the asphalt granular concrete layer is adjacent to the inner side of the first force support layer, and the geotextile layer is arranged between the asphalt granular concrete layer and the second force support layer; The composite vibration isolation layer is further provided with a spring rubber support; a first end of the spring rubber support is anchored in the first force support layer, a second end of the spring rubber support passes through through holes in the asphalt granular concrete layer, the geotextile layer, and the second force support layer in turn, and is locked with the second force support layer through a fastener; The first stress support layer is a combined support body composed of a steel arch lattice and sprayed rubber concrete in mine construction, or a combined support body composed of rubber mortar and shield segments in shield construction. The second stress support layer is a steel plate with a plurality of honeycomb vibration absorption holes.

2. The construction method of a subway tunnel vibration-reducing structure according to claim 1, characterized by, When the first stress support layer is a combined support body composed of a steel arch lattice and sprayed rubber concrete, each ring of the steel arch lattice is processed into at least two sections, and adjacent sections of the steel arch lattice are connected by a friction deformation connector, and a steel arch lattice deformation joint with a narrow top and a wide bottom is formed at the connection. The friction deformation connector is sleeved on the outer periphery of the steel arch lattice, and the contact surface between the friction deformation connector and the steel arch lattice is provided with a notch for increasing friction.

3. The construction method of a subway tunnel vibration-reducing structure according to claim 1, characterized by, The spring rubber support includes a cylindrical rubber and a spring embedded in the cylindrical rubber, the cylindrical rubber is embedded in the asphalt granular concrete layer, and the height of the cylindrical rubber is the same as the thickness of the asphalt granular concrete layer. The first end of the spring forms a pre-buried anchoring section, which protrudes from the cylindrical rubber and is anchored in the first stress support layer. The second end of the spring forms a threaded connection section, which sequentially passes through the geotextile layer and the second stress support layer, and is locked with the second stress support layer by a nut.

4. The construction method of a subway tunnel vibration-reducing structure according to claim 1, characterized by, The raw materials of the asphalt granular concrete layer include asphalt particles, cement, coarse gravel, fine gravel, medium sand, mineral powder and water reducing agent. The particle size of the asphalt particles is not greater than 10 mm, and the mass of the asphalt particles accounts for 5%-7% of the total mass of the aggregate. The mass of the mineral powder accounts for 1%-3% of the total mass of the aggregate. The mass ratio of the cement, medium sand and stone is 1:(1.1-2.3):(2.7-3.3).

5. The construction method of a subway tunnel vibration-reducing structure according to claim 1, wherein The raw materials of the rubber mortar include rubber particles, cement, medium sand, fly ash, bentonite and water reducing agent. The rubber particles are particles obtained by crushing waste tires, and the mass of the rubber particles accounts for 10%-15% of the total mass of the rubber mortar; the mass of the cement accounts for 20%-25% of the total mass of the rubber mortar, and the mass of the bentonite accounts for 3%-5% of the total mass of the rubber mortar.

6. The construction method of a subway tunnel vibration-reducing structure according to claim 1, wherein The raw materials of the sprayed rubber concrete include rubber particles, fine gravel, medium sand, cement, bentonite and quick-setting agent. The rubber particles are particles obtained by crushing waste tires, and the particle size of the particles is 0-2.5 mm, and the mass of the rubber particles accounts for 10%-15% of the total mass of the aggregate; the fine gravel is pebble or gravel, and the particle size is ≤15 mm, and the clay content is ≤1%; The mass of the cement accounts for 25%-30% of the total mass of the aggregate, and the mass of the bentonite accounts for 3%-5% of the total mass of the aggregate.

7. The construction method of the subway tunnel vibration reduction structure according to claim 1, wherein In step S2, the steel plate of the tunnel ring installation unit is divided into 6-9 installation blocks, 2-3 side wall blocks for each of the two arch waist, one bottom plate block and one capping block, and the circular arc angle of the bottom plate block is the largest, the circular arc angle of the side wall block is the second, and the circular arc angle of the capping block is the smallest; the geotextile is adhered to the steel plate by structural adhesive.

8. The construction method of a subway tunnel vibration-reducing structure according to claim 7, characterized by, In step S6, the vibration hammer is powered by compressed air provided by an air compressor, the air compressor is connected to an air pressure pipe, and an air pressure pipe joint and an air pressure pipe valve are arranged on the air pressure pipe. The vibration hammer is held by a worker, a self-locking valve is arranged on the handle of the vibration hammer, when the self-locking valve is buckled by a finger, the self-locking valve is opened, compressed air is sprayed through the air jet hole of the vibration hammer, the vibration hammer is tightly vibrated against the steel plate, and the asphalt granular concrete is vibrated and compacted.

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