High-speed railway tunnel portal cross-section enlarged pressure relief buffer structure and construction method

Abstract

This invention relates to the field of tunnel portal pressure reduction technology, specifically a constant-section enlarged pressure reduction buffer structure and construction method for high-speed railway tunnel portals. The constant-section enlarged pressure reduction buffer structure for high-speed railway tunnel portals includes multiple constant-section enlarged cross-section buffer structures. A standard cross-section buffer structure is erected between adjacent constant-section enlarged cross-section buffer structures. A first support structure is provided between the standard cross-section buffer structure and the adjacent constant-section enlarged cross-section buffer structures. The first support structure has a first curved channel along the length of the railway line. This invention's constant-section enlarged pressure reduction buffer structure for high-speed railway tunnel portals can more effectively reduce the initial compression wave and micro-pressure wave generated when trains enter and exit the tunnel portal; that is, it can reduce the length of the buffer structure while achieving a good reduction in the initial compression wave and micro-pressure wave generated when trains enter and exit the tunnel portal.

Description

Technical Field

[0001] This invention relates to the field of tunnel portal pressure reduction technology, and in particular to a pressure reduction buffer structure with an enlarged cross-section at the portal of a high-speed railway tunnel and its construction method. Background Technology

[0002] Currently, to build a modern transportation network that combines speed and safety, and due to continuous scientific research and the gradual overcoming of safety issues in high-speed train operation, the operating speed of high-speed trains is constantly increasing. Currently, high-speed trains can operate at speeds of 400 km / h, and will continue to strive for even higher speeds in the future. This increase in speed leads to increasingly prominent aerodynamic problems in tunnels.

[0003] Since the operation of high-speed trains, the danger posed by micropressure waves at tunnel entrances to the surrounding environment has become increasingly prominent with increasing train speed. The frequency domain of these micropressure waves is mainly concentrated in the low-frequency region, with energy primarily below 100Hz, and in most cases below 20Hz. The portion above 20Hz mainly creates a sonic boom audible to the human ear. The portion below 20Hz primarily causes violent shaking of lightweight structures near the tunnel exit. Studies have shown that the peak value of the micropressure waves at the tunnel entrance is directly proportional to the cube of the train speed. When a train travels at 400km / h through a 100m tunnel... 2 In a standard single-bore double-track tunnel, the peak value of the micro-pressure wave at 20m from the tunnel entrance is 135Pa, far exceeding the specified requirement (50Pa). Currently, setting up a buffer structure at the tunnel entrance is the most basic method to mitigate the micro-pressure wave at the tunnel exit.

[0004] However, using a single-form, short-length buffer structure at the tunnel entrance is insufficient to reduce micro-pressure waves within the specified limits. Due to the terrain and engineering requirements at the tunnel entrance, the issue of reducing the length and cross-section of the buffer structure while achieving a good buffering effect urgently needs to be addressed. Summary of the Invention

[0005] The purpose of this invention is to address the problem in the prior art that it is difficult to reduce the micro-pressure wave at the tunnel entrance to within the specified limits using a single-form buffer structure with a relatively short longitudinal length. This invention provides a pressure-reducing buffer structure with an enlarged cross-section at the entrance of a high-speed railway tunnel and a construction method thereof.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A high-speed railway tunnel entrance equal-section enlarged pressure-reducing buffer structure includes multiple equal-section enlarged cross-section buffer structures disposed at the end of a standard cross-section tunnel. The multiple equal-section enlarged cross-section buffer structures are spaced apart along the track direction. The cross-sectional area of ​​the inner cavity of the equal-section enlarged cross-section buffer structure is larger than the cross-sectional area of ​​the inner cavity of the standard cross-section tunnel. A standard cross-section buffer structure is erected between adjacent equal-section enlarged cross-section buffer structures. The cross-sectional area of ​​the inner cavity of the standard cross-section buffer structure is smaller than the cross-sectional area of ​​the equal-section enlarged cross-section buffer structure. A first support structure is disposed between the standard cross-section buffer structure and the adjacent equal-section enlarged cross-section buffer structure. The first support structure has a first curved channel along the length of the track.

[0008] The present application describes a high-speed railway tunnel entrance with an enlarged cross-section pressure-reducing buffer structure. The cross-sectional area of ​​the inner cavity of the enlarged cross-section buffer structure is larger than that of the standard cross-section tunnel. This design prolongs the rise time of the compression wave, thereby reducing the pressure gradient and thus achieving the effect of reducing micro-pressure waves.

[0009] Based on the above, the high-speed railway tunnel entrance constant cross-section enlarged pressure-reducing buffer structure described in this application utilizes a constant cross-section enlarged section buffer structure and a standard cross-section buffer structure to divide the buffer structure into multiple sections. The constant cross-section enlarged section buffer structure forms an enlarged chamber, increasing the wall roughness. This creates a certain length of overlap and a certain radial height gap between the constant cross-section enlarged section buffer structure and the adjacent standard cross-section buffer structure in the track direction. When a pressure wave passes through the high-speed railway tunnel entrance constant cross-section enlarged pressure-reducing buffer structure described in this application, the alternating changes in the net cross-sectional area of ​​the buffer structure caused by the constant cross-section enlarged section buffer structure and the standard cross-section buffer structure generate expansion and compression effects within the enlarged chamber. Due to the viscosity of air, air flows along the walls of the enlarged chamber and enters the gap between the buffer structure and the standard cross-section. A first support structure is set in the gap, and the first support structure has a flow channel with a first curved channel along the length of the line, which further increases the air flow resistance, thereby more effectively reducing the initial compression wave and micro-pressure wave generated when the train enters and exits the tunnel. Through the combination of the equal cross-section enlarged section buffer structure and the standard cross-section buffer structure, and the synergistic effect of the equal cross-section enlarged section buffer structure and the standard cross-section buffer structure with the first curved channel, the equal cross-section enlarged pressure-reducing buffer structure of the high-speed railway tunnel entrance described in this application can more effectively reduce the initial compression wave and micro-pressure wave generated when the train enters and exits the tunnel. That is, while achieving a good effect of reducing the initial compression wave and micro-pressure wave generated when the train enters and exits the tunnel, the length of the buffer structure can be effectively reduced.

[0010] Preferably, the cross-sectional area of ​​the inner cavity of the standard cross-section buffer structure is greater than or equal to the cross-sectional area of ​​the inner cavity of the standard cross-section tunnel.

[0011] Preferably, the first curved channel is a Z-shaped channel or an S-shaped channel.

[0012] Preferably, along the radial direction of the equal-section enlarged cross-section buffer structure, the distance between the inner wall of the equal-section enlarged cross-section buffer structure and the outer wall of the standard cross-section buffer structure is 0.7-1m.

[0013] Preferably, the longitudinal erection length of the equal-section enlarged cross-section buffer structure and the standard cross-section buffer structure along the length of the line is 1.3-1.7m.

[0014] Preferably, the first support structure includes two rows of concrete diaphragm groups, wherein the concrete diaphragm group near the middle of the standard cross-section buffer structure is the first concrete diaphragm group, and the other row of concrete diaphragm groups is the second concrete diaphragm group. The first concrete diaphragm group includes a plurality of first concrete diaphragms arranged at intervals along the circumference of the standard cross-section buffer structure, and the second concrete diaphragm group includes a plurality of second concrete diaphragms arranged at intervals along the circumference of the standard cross-section buffer structure. The first concrete diaphragms and the second concrete diaphragms are staggered and form a first curved channel along the length of the line.

[0015] Preferably, the concrete used to make the first concrete partition and the second concrete partition is sound-absorbing concrete.

[0016] Preferably, the spacing between adjacent first concrete diaphragms in the first concrete diaphragm group is smaller the farther away from the standard cross-section tunnel;

[0017] Preferably, the width of adjacent first concrete diaphragms in the first concrete diaphragm group along the circumference of the standard cross-section buffer structure is greater the farther away from the standard cross-section tunnel.

[0018] Preferably, a second support structure is provided between the equal-section enlarged cross-section buffer structure near the standard cross-section tunnel and the standard cross-section tunnel, and the second support structure has a second curved channel along the length of the line.

[0019] Preferably, the second support structure includes two rows of concrete diaphragm groups, wherein the concrete diaphragm group away from the equal cross-section enlarged section buffer structure is the third concrete diaphragm group, and the other row of concrete diaphragm groups is the fourth concrete diaphragm group. The third concrete diaphragm group includes several third concrete diaphragms arranged at intervals along the circumference of the standard cross-section tunnel, and the fourth concrete diaphragm group includes several fourth concrete diaphragms arranged at intervals along the circumference of the standard cross-section tunnel. The third concrete diaphragms and the fourth concrete diaphragms are staggered and form a second curved channel along the length of the line.

[0020] Preferably, the final pressure loss ΔP of the pressure wave passing through the equal-section enlarged pressure-reducing buffer structure at the entrance of the high-speed railway tunnel is... Z The design includes the following steps:

[0021] A1. Based on the axial length L of the equal-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel and the equivalent diameter d of the equal-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel, the pressure loss value ΔP when the pressure wave passes through the equal-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel is obtained;

[0022] A2. Based on the cross-sectional area of ​​the inner cavity of the equal-section enlarged-type buffer structure and the cross-sectional area of ​​the standard-section buffer structure, the local resistance coefficient ξ1 of the sudden expansion of the cross-section of the equal-section enlarged-type pressure-reducing buffer structure at the entrance of the high-speed railway tunnel and the local resistance coefficient ξ2 of the sudden contraction of the cross-section of the equal-section enlarged-type pressure-reducing buffer structure at the entrance of the high-speed railway tunnel are obtained.

[0023] A3. Based on the local resistance coefficient ξ1 of the sudden expansion of the cross-section of the constant-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel and the local resistance coefficient ξ2 of the sudden contraction of the cross-section of the constant-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel, the cumulative local pressure loss value ΔP of the constant-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel is obtained. j ;

[0024] A4. The cumulative local pressure loss value ΔP of the equal-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel. j The final local pressure loss ΔP3 of the enlarged cross-section pressure-reducing buffer structure at the entrance of a high-speed railway tunnel is obtained by reduction.

[0025] A5. Based on the pressure loss value ΔP when the pressure wave passes through the equal-section enlarged pressure-reducing buffer structure at the entrance of the high-speed railway tunnel, and the final local pressure loss ΔP3 of the equal-section enlarged pressure-reducing buffer structure at the entrance of the high-speed railway tunnel, the final pressure loss value ΔP of the pressure wave passing through the equal-section enlarged pressure-reducing buffer structure at the entrance of the high-speed railway tunnel is obtained. Z .

[0026] This application also discloses a construction method for the equal-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel as described in this application, comprising the following steps:

[0027] Step 1: Based on the lower dimensions of the equal-section enlarged cross-section buffer structure, excavate a foundation pit in the ground and pour concrete to form the structural foundation of the equal-section enlarged pressure-reducing buffer structure at the entrance of the high-speed railway tunnel;

[0028] Step 2: Arrange the joint reinforcement bars in a timely manner before the concrete of the foundation of the structure solidifies.

[0029] Step 3: Tie the bottom slab reinforcement, the standard cross-section buffer structure wall reinforcement of a certain height, and the equal cross-section enlarged cross-section buffer structure wall reinforcement of a certain height, and pour the concrete to form the bottom slab, wherein the bottom slab is located at the top of the structural foundation;

[0030] Step 4: After the concrete strength of the formed base plate reaches the design requirements, tie the wall reinforcement of the standard cross-section tunnel end and the remaining wall reinforcement of the standard cross-section buffer structure, and then pre-embed the second support structure and each first support structure according to the design position before pouring the wall concrete of the standard cross-section buffer structure to form the standard cross-section tunnel and each standard cross-section buffer structure.

[0031] Step 5: After the concrete of the walls of the standard cross-section tunnel and each standard cross-section buffer structure reaches the design strength, start tying the remaining wall reinforcement of each equal cross-section enlarged cross-section buffer structure, and install and fix the second support structure and the first support structure with the corresponding wall reinforcement of the equal cross-section enlarged cross-section buffer structure. Then, pour concrete to form the equal cross-section enlarged cross-section buffer structure, and finally form the equal cross-section enlarged pressure reduction buffer structure for the entrance of the high-speed railway tunnel.

[0032] The construction method of the equal-section enlarged pressure-reducing buffer structure for high-speed railway tunnel entrance described in this application is convenient to implement, simple in structure, and has good overall structure. It can alleviate micro-pressure waves at the tunnel entrance with a relatively short buffer structure length and is less restricted by the terrain of the tunnel entrance.

[0033] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0034] 1. This application describes a high-speed railway tunnel entrance equal-section enlarged pressure-reducing buffer structure. The cross-sectional area of ​​the equal-section enlarged buffer structure is larger than that of the standard cross-section tunnel cavity. This design prolongs the rise time of the compression wave, thereby reducing the pressure gradient and achieving the effect of reducing micro-pressure waves. Based on the above, this application describes a high-speed railway tunnel entrance equal-section enlarged pressure-reducing buffer structure that divides the buffer structure into multiple sections using an equal-section enlarged buffer structure and a standard cross-section buffer structure. The equal-section enlarged buffer structure forms an enlarged chamber, increases the wall roughness, and creates a certain length of overlap and a certain radial height gap between the equal-section enlarged buffer structure and the overlapping standard cross-section buffer structure in the track direction. When a pressure wave passes through the high-speed railway tunnel entrance equal-section enlarged pressure-reducing buffer structure described in this application, the alternating changes in the net cross-sectional area of ​​the buffer structure caused by the equal-section enlarged buffer structure and the standard cross-section buffer structure result in expansion and compression effects within the enlarged chamber. Because air has a certain viscosity, it flows along the walls of the enlarged chamber and enters the gap between the standard cross-section and the tunnel. A first support structure is installed in this gap, featuring a flow channel with a first curved path along the track length. This further increases the airflow resistance, thereby more effectively reducing the initial compression wave and micro-pressure wave generated when a train enters or exits the tunnel. Through the combined installation of the equal-section enlarged cross-section buffer structure and the standard cross-section buffer structure, and the synergistic effect of these structures with the first curved path, the equal-section enlarged pressure-reducing buffer structure for high-speed railway tunnel entrances described in this application can more effectively reduce the initial compression wave and micro-pressure wave generated when a train enters or exits the tunnel. In other words, while achieving a good reduction in the initial compression wave and micro-pressure wave generated when a train enters or exits the tunnel, the length of the buffer structure can be effectively reduced.

[0035] 2. The construction method of the equal-section enlarged pressure reduction buffer structure for high-speed railway tunnel entrance described in this application is convenient to implement, simple in structure, and has good overall structure. It can alleviate micro-pressure waves at the tunnel entrance with a relatively short buffer structure length and is less restricted by the terrain of the tunnel entrance. Attached Figure Description

[0036] Figure 1 This is a three-dimensional structural schematic diagram of a high-speed railway tunnel entrance with an enlarged cross-section pressure-reducing buffer structure according to the present invention.

[0037] Figure 2 This is a top view schematic diagram of a high-speed railway tunnel entrance equal cross-section enlarged type pressure reduction buffer structure according to the present invention (without the equal cross-section enlarged section buffer structure).

[0038] Figure 3 This is an appendix to the present invention. Figure 2 Enlarged schematic diagram of section B in the middle.

[0039] Figure 4 This is a schematic diagram of the main structure of a high-speed railway tunnel entrance with an enlarged cross-section pressure-reducing buffer structure according to the present invention.

[0040] Figure 5 This is an appendix to the present invention. Figure 4 Schematic diagram of the sectional view along the AA direction.

[0041] Figure 6 This is a three-dimensional schematic diagram of the standard cross-section buffer structure of the present invention and the corresponding concrete diaphragm assembly.

[0042] Figure 7 This is a top view schematic diagram of the standard cross-section buffer structure of the present invention and the corresponding concrete diaphragm assembly.

[0043] Figure 8 This is a top view schematic diagram of the standard cross-section tunnel and the corresponding concrete diaphragm assembly of the present invention.

[0044] Reference numerals: 1-Standard cross-section tunnel (1); 2-Equal cross-section enlarged cross-section buffer structure (2); 3-Standard cross-section buffer structure (3); 4-First support structure (4); 5-First concrete diaphragm group (5); 6-Second concrete diaphragm group (6); 7-First concrete diaphragm (7); 8-Second concrete diaphragm (8); 9-First curved passage (9); 10-Second support structure (10); 11-Second curved passage (11); 12-Third concrete diaphragm group (12) Concrete diaphragm group (12); 13-Fourth concrete diaphragm group (13); 14-Third concrete diaphragm (14); 15-Fourth concrete diaphragm (15); 16-Inner cavity of equal cross-section enlarged section buffer structure (16); 17-Inner cavity of standard cross-section tunnel (17); 18-Inner cavity of standard cross-section buffer structure (18); 20-Structural foundation (20); 21-Bottom slab (21); 31-First standard cross-section buffer structure; 32-Second standard cross-section buffer structure. Detailed Implementation

[0045] The present invention will now be described in detail with reference to the accompanying drawings.

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0047] Example 1

[0048] like Figure 1-8As shown in this embodiment, a high-speed railway tunnel entrance equal-section enlarged type pressure-reducing buffer structure includes multiple equal-section enlarged cross-section buffer structures 2 disposed at the end of a standard cross-section tunnel 1. The multiple equal-section enlarged cross-section buffer structures 2 are spaced apart along the line direction. The cross-sectional area of ​​the inner cavity 16 of the equal-section enlarged cross-section buffer structure is larger than the cross-sectional area of ​​the inner cavity 17 of the standard cross-section tunnel. A standard cross-section buffer structure 3 is erected between adjacent equal-section enlarged cross-section buffer structures 2. The cross-sectional area of ​​the inner cavity 18 of the standard cross-section buffer structure is smaller than the cross-sectional area of ​​the inner cavity 16 of the equal-section enlarged cross-section buffer structure. A first support structure 4 is disposed between the standard cross-section buffer structure 3 and the adjacent equal-section enlarged cross-section buffer structure 2. The first support structure 4 has a first curved channel 9 along the line length direction.

[0049] The cross-sectional area of ​​the inner cavity 18 of the standard cross-section buffer structure is greater than or equal to the cross-sectional area of ​​the inner cavity 17 of the standard cross-section tunnel.

[0050] Furthermore, the cross-sectional area of ​​the inner cavity 18 of the standard cross-section buffer structure corresponds to the cross-sectional area of ​​the inner cavity 17 of the standard cross-section tunnel.

[0051] The inner cavity 16 of the equal cross-section enlarged section buffer structure, the inner cavity 17 of the standard cross-section tunnel, and the inner cavity 18 of the standard cross-section buffer structure are all corresponding cavities through which trains pass.

[0052] The first curved channel 9 is a Z-shaped channel or an S-shaped channel.

[0053] At the entrance and exit of the standard cross-section tunnel 1, an enlarged cross-section buffer structure 2 and a standard cross-section buffer structure 3 are installed. Along the radial direction of the enlarged cross-section buffer structure 2, the distance between the inner wall of the enlarged cross-section buffer structure 2 and the outer wall of the standard cross-section buffer structure 3 is 0.7-1m.

[0054] The longitudinal erection length of the equal cross-section enlarged section buffer structure 2 and the standard cross-section buffer structure 3 is 1.3-1.7m, and the overlapping area is connected by two first support structures 4.

[0055] An enlarged cavity is formed by using an enlarged cross-section with equal cross-section, and then a first curved channel 9 is formed by a transverse diaphragm made of sound-absorbing concrete to reduce pressure.

[0056] Specifically, the second concrete diaphragm group 6 is 0.4-0.6m away from the edge of the corresponding standard cross-section buffer structure 3, and the first concrete diaphragm group 5 is 0.8m-1.2m away from the edge of the corresponding standard cross-section buffer structure 3.

[0057] The following explanation uses two standard cross-section buffer structures 3 as examples: along the route, the standard cross-section buffer structure 3 closest to the standard cross-section tunnel 1 is the first standard cross-section buffer structure 31, and the standard cross-section buffer structure 3 furthest from the standard cross-section tunnel 1 is the second standard cross-section buffer structure 32.

[0058] In the second concrete diaphragm group 6 on the outer wall of the first standard cross-section buffer structure 31 and the second standard cross-section buffer structure 32, the second concrete diaphragm 8 has a thickness of 0.13-0.17m along the length of the line, a radial height of 0.6-1m along the standard cross-section buffer structure 3, and a width of 0.5-0.7m along the direction of the standard cross-section buffer structure 3.

[0059] In the fourth concrete diaphragm group 13 on the outer wall of the standard cross-section tunnel 1, the fourth concrete diaphragm 15 has a thickness of 0.13-0.17m along the length of the line, a radial height of 0.6-1m along the standard cross-section buffer structure 3, and a width of 0.5-0.7m along the direction of the standard cross-section buffer structure 3.

[0060] In the third concrete diaphragm group 12 on the outer wall of the standard cross-section tunnel 1, the third concrete diaphragm 14 has a thickness of 0.13-0.17m along the length of the track, a radial height of 0.6-1m along the standard cross-section buffer structure 3, and a width of 0.7-0.9m along the direction of the standard cross-section buffer structure 3.

[0061] In the first concrete diaphragm group 5 on the outer wall of the first standard cross-section buffer structure 31, the first concrete diaphragm 7 has a thickness of 0.13-0.17m along the length of the line, a radial height of 0.6-1m along the standard cross-section buffer structure 3, and a width of 0.8-1m along the direction of the standard cross-section buffer structure 3.

[0062] In the first concrete diaphragm group 5 on the outer wall of the second standard cross-section buffer structure 32, the first concrete diaphragm 7 has a thickness of 0.13-0.17m along the length of the line, a radial height of 0.6-1m along the standard cross-section buffer structure 3, and a width of 0.9-1.2m along the direction of the standard cross-section buffer structure 3.

[0063] In actual engineering, the thickness of the first concrete partition 7, the second concrete partition 8, the third concrete partition 14 and the fourth concrete partition 15 can be equal along the length of the line, and their radial heights along the standard cross-section buffer structure 3 can also be equal.

[0064] The first concrete partition 7, the second concrete partition 8, the third concrete partition 14, and the fourth concrete partition 15 are preferably fan-shaped.

[0065] In the second concrete diaphragm group 6 on the outer wall of the first standard cross-section buffer structure 31 and the second standard cross-section buffer structure 32, the interval between adjacent second concrete diaphragms 8 is 0.5-0.7m.

[0066] In the fourth concrete diaphragm group 13 on the outer wall of the standard cross-section tunnel 1, the interval between adjacent fourth concrete diaphragms 15 is 0.5-0.7m; in the third concrete diaphragm group 12 on the outer wall of the standard cross-section tunnel 1, the interval between adjacent third concrete diaphragms 14 is 0.3-0.5m.

[0067] In the first concrete diaphragm group 5 on the outer wall of the first standard cross-section buffer structure 31, the interval between adjacent first concrete diaphragms 7 is 0.2-0.4m;

[0068] In the first concrete diaphragm group 5 on the outer wall of the second standard cross-section buffer structure 32, the first concrete diaphragms 7 are spaced 0.1-0.3m apart.

[0069] The high-speed railway tunnel entrance equal-section enlarged pressure-reducing buffer structure described in this application has an inner cavity 16 with a cross-sectional area larger than that of the standard cross-section tunnel inner cavity 17. This design prolongs the rise time of the compression wave, thereby reducing the pressure gradient and thus achieving the effect of reducing micro-pressure waves.

[0070] The high-speed railway tunnel entrance constant cross-section enlarged pressure-reducing buffer structure described in this application can further reduce the pressure gradient. The specific principle is as follows: The buffer structure is divided into multiple sections using a constant cross-section enlarged buffer structure 2 and a standard cross-section buffer structure 3. The constant cross-section enlarged buffer structure 2 forms an enlarged chamber, increasing the wall roughness. This creates a certain length of overlap and a certain radial height gap between the constant cross-section enlarged buffer structure 2 and the overlapping standard cross-section buffer structure 3 in the track direction. When a pressure wave passes through the high-speed railway tunnel entrance constant cross-section enlarged pressure-reducing buffer structure described in this application, the alternating changes in the net cross-sectional area of ​​the buffer structure caused by the constant cross-section enlarged buffer structure 2 and the standard cross-section buffer structure 3 generate expansion and compression effects within the enlarged chamber. Due to the viscosity of air, air flows along the walls of the enlarged chamber and enters the gap between the buffer structure and the standard cross-section. A first support structure 4 is set in the gap. The first support structure 4 has a flow channel with a first curved channel 9 along the length of the line, which further increases the air flow resistance, thereby more effectively reducing the initial compression wave and micro-pressure wave generated when the train enters or exits the tunnel. Through the placement of the equal cross-section enlarged section buffer structure 2 and the standard cross-section buffer structure 3, and the synergistic effect of the equal cross-section enlarged section buffer structure 2 and the standard cross-section buffer structure 3 with the first curved channel 9, the equal cross-section enlarged pressure-reducing buffer structure for high-speed railway tunnel entrances described in this application can more effectively reduce the initial compression wave and micro-pressure wave generated when the train enters or exits the tunnel. That is, while achieving a good effect in reducing the initial compression wave and micro-pressure wave generated when the train enters or exits the tunnel, the length of the buffer structure can be reduced.

[0071] In general, compared with the prior art, the above-described technology conceived by this invention can achieve the following advantages:

[0072] Beneficial effects:

[0073] 1. The present invention provides a pressure-reducing buffer structure with an enlarged cross section of equal cross section at the tunnel entrance and exit, which can effectively reduce the initial compression wave and pressure gradient generated when the train enters the tunnel, reduce the peak value of the micro-pressure wave at the tunnel entrance, and reduce its impact on the surrounding environment.

[0074] 2. This invention is easy to implement, has a simple structure, good overall structure, and can alleviate micro-pressure waves at the tunnel entrance with a shorter buffer structure length. It is less restricted by the terrain at the tunnel entrance.

[0075] like Figure 4As shown in this embodiment, a high-speed railway tunnel entrance equal-section enlarged type pressure-reducing buffer structure is provided at the entrance and exit of the standard cross-section tunnel 1. The net area of ​​the equal-section enlarged type buffer structure 2 is 1.3-1.4 times that of the standard cross-section tunnel 1, and it is of equal cross-section form with a length of 30m.

[0076] The equal-section enlarged cross-section buffer structure 2 and the standard cross-section buffer structure 3 are connected by a concrete diaphragm assembly.

[0077] During construction, the first concrete partition 7, the second concrete partition 8, the third concrete partition 14 and the fourth concrete partition 15 are generally prefabricated, with connecting steel bars pre-embedded at both ends to ensure the integrity of the equal cross-section enlarged section buffer structure 2 and the standard cross-section buffer structure 3.

[0078] This invention discloses a constant-section enlarged-type pressure-reducing buffer structure for high-speed railway tunnel entrances. The structure comprises four parts: a standard cross-section tunnel 1, a standard cross-section buffer structure 3, a constant-section enlarged-section buffer structure, and concrete diaphragm assemblies 4. The buffer structure is located at the tunnel entrance and is generally 25-30m long. The net area of ​​the constant-section enlarged-section is 1.3-1.4 times that of the standard cross-section tunnel 1. Each section of the standard cross-section buffer structure 3 and the constant-section enlarged-section buffer structure 2 is 6-8m long longitudinally, spaced apart and overlapping by 1.2-1.8m along the track direction. Concrete diaphragm assemblies 4, made of sound-absorbing concrete, are arranged in the overlapping area of ​​adjacent sections, uniformly distributed circumferentially and staggered longitudinally, connecting the inner and outer tunnel walls. The gaps in the first curved passage 9 are distributed along the track at certain intervals. This invention has a simple structure, is easy to construct, has a short buffer structure length, and is less restricted by the terrain at the tunnel entrance. The diaphragm enhances the overall integrity of the buffer structure, effectively reducing the initial compression wave and the peak value of the micro-pressure wave at the tunnel exit when the train enters the tunnel, meeting the pressure comfort requirements of passengers and reducing the environmental harm caused by micro-pressure waves.

[0079] The beneficial effects of this embodiment are as follows: The equal-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel described in this embodiment has a cross-sectional area 16 of the equal-section enlarged cross-section buffer structure that is larger than the cross-sectional area 17 of the standard cross-section tunnel. This design prolongs the rise time of the compression wave, thereby reducing the pressure gradient and thus achieving the effect of reducing micro-pressure waves.

[0080] Based on the above, the high-speed railway tunnel entrance equal-section enlarged pressure-reducing buffer structure described in this application utilizes an equal-section enlarged cross-section buffer structure 2 and a standard cross-section buffer structure 3 to divide the buffer structure into multiple sections. The equal-section enlarged cross-section buffer structure 2 forms an enlarged chamber, increasing the wall roughness. This creates a certain length of overlap and a certain radial height gap between the equal-section enlarged cross-section buffer structure 2 and the overlapping standard cross-section buffer structure 3 in the track direction. When a pressure wave passes through the high-speed railway tunnel entrance equal-section enlarged pressure-reducing buffer structure described in this application, the alternating changes in the net cross-sectional area of ​​the buffer structure caused by the equal-section enlarged cross-section buffer structure 2 and the standard cross-section buffer structure 3 result in expansion and compression effects within the enlarged chamber. Due to the viscosity of air, air flows along the walls of the enlarged chamber and enters the gap between the buffer structure and the standard cross-section. A first support structure 4 is set in the gap. The first support structure 4 has a flow channel with a first curved channel 9 along the length of the line, which further increases the air flow resistance, thereby more effectively reducing the initial compression wave and micro-pressure wave generated when the train enters or exits the tunnel. Through the placement of the equal cross-section enlarged section buffer structure 2 and the standard cross-section buffer structure 3, and the synergistic effect of the equal cross-section enlarged section buffer structure 2 and the standard cross-section buffer structure 3 with the first curved channel 9, the equal cross-section enlarged pressure-reducing buffer structure for high-speed railway tunnel entrances described in this application can more effectively reduce the initial compression wave and micro-pressure wave generated when the train enters or exits the tunnel. That is, while achieving a good effect in reducing the initial compression wave and micro-pressure wave generated when the train enters or exits the tunnel, the length of the buffer structure can be effectively reduced.

[0081] Example 2

[0082] like Figure 1-8 As shown, this application also discloses a pressure-reducing buffer structure with an enlarged cross-section at the entrance of a high-speed railway tunnel as described in this application, wherein the final pressure loss ΔP of the pressure wave passing through the enlarged cross-section pressure-reducing buffer structure at the entrance of the high-speed railway tunnel is... Z The design includes the following steps:

[0083] A1. Based on the axial length L of the equal-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel and the equivalent diameter d of the equal-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel, the pressure loss value ΔP when the pressure wave passes through the equal-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel is obtained;

[0084] A2. Based on the cross-sectional area of ​​the inner cavity 16 of the equal-section enlarged buffer structure and the cross-sectional area of ​​the inner cavity 18 of the standard cross-section buffer structure, the local resistance coefficient ξ1 of the sudden expansion of the cross-section of the equal-section enlarged pressure-reducing buffer structure at the entrance of the high-speed railway tunnel and the local resistance coefficient ξ2 of the sudden contraction of the cross-section of the equal-section enlarged pressure-reducing buffer structure at the entrance of the high-speed railway tunnel are obtained.

[0085] A3. Based on the local resistance coefficient ξ1 of the sudden expansion of the cross-section of the constant-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel and the local resistance coefficient ξ2 of the sudden contraction of the cross-section of the constant-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel, the cumulative local pressure loss value ΔP of the constant-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel is obtained. j ;

[0086] A4. The cumulative local pressure loss value ΔP of the equal-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel. j The final local pressure loss ΔP3 of the enlarged cross-section pressure-reducing buffer structure at the entrance of a high-speed railway tunnel is obtained by reduction.

[0087] A5. Based on the pressure loss value ΔP when the pressure wave passes through the equal-section enlarged pressure-reducing buffer structure at the entrance of the high-speed railway tunnel, and the final local pressure loss ΔP3 of the equal-section enlarged pressure-reducing buffer structure at the entrance of the high-speed railway tunnel, the final pressure loss value ΔP of the pressure wave passing through the equal-section enlarged pressure-reducing buffer structure at the entrance of the high-speed railway tunnel is obtained. Z .

[0088] Specifically, the friction loss is calculated as follows: Darcy's formula is used to describe the pressure drop phenomenon that occurs when viscous fluids flow through a pipeline, and its expression is shown in formula (1):

[0089]

[0090] In the formula, ΔP is the pressure loss value when the pressure wave passes through the equal-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel; L is the pipe length, which is taken as the axial length of the equal-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel; d is the pipe diameter, which is taken as the equivalent diameter of the equal-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel; L / d is called the geometric factor of the pipe; ρ is the air density; v is the average flow velocity in the pipe, which is taken as the average flow velocity when the pressure wave passes through the equal-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel; λ is the friction coefficient, which is dimensionless and is not a constant. It is usually determined by experimental results or empirical formulas and is a function of the fluid Reynolds number Re and the relative roughness of the pipe wall. Its value can be obtained by consulting the Moody diagram. Depending on the different flow patterns of the fluid in the pipe, its calculation formula is shown in formulas (2) to (4):

[0091] For laminar flow in a circular tube:

[0092] For the rough transition zone of a circular tube:

[0093] For the rough region of turbulent flow in a circular pipe:

[0094] In the formula: Re is the Reynolds number, calculated as follows: d is the pipe diameter, and μ is the viscosity coefficient of air, taken as 1.87 × 10⁻⁶. -5 Pa.s.

[0095] Formula for calculating local loss:

[0096] The local resistance coefficient of a high-speed railway tunnel portal with a uniform cross-section enlargement type pressure-reducing buffer structure that suddenly expands in cross-section is: ξ1=(1-A1 / A2) 2

[0097] Where A1 is the original cavity cross-sectional area under the condition of sudden cross-sectional expansion, and the cross-sectional area of ​​the standard cross-sectional buffer structure cavity 18 is taken; A2 is the cavity cross-sectional area after the sudden cross-sectional expansion, and the cross-sectional area of ​​the equal cross-section expanded cross-sectional buffer structure cavity 16 is taken.

[0098] The local pressure loss due to the sudden expansion of the cross-section of the equal-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel: ΔP1=0.5ξ1ρv 2

[0099] The local resistance coefficient of a high-speed railway tunnel portal with a uniform cross-section enlarged type pressure-reducing buffer structure that suddenly contracts is: ξ2=0.5(1-A3 / A4)

[0100] Wherein, A3 is the cross-sectional area of ​​the inner cavity after contraction under the condition of sudden cross-sectional contraction, which is taken as the cross-sectional area of ​​the inner cavity of the standard cross-section buffer structure 18; A4 is the original cross-sectional area of ​​the inner cavity under the condition of sudden cross-sectional contraction, which is taken as the cross-sectional area of ​​the inner cavity of the equal cross-section enlarged cross-section buffer structure 16.

[0101] Local pressure loss due to sudden contraction of the cross-section of a constant-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel: ΔP2=0.5ξ2ρv 2

[0102] Cumulative local pressure loss value of the enlarged cross-section pressure-reducing buffer structure at the entrance of a high-speed railway tunnel: ΔP j =0.5ξ1ρv 2 n1+0.5ξ2ρv 2 n2

[0103] Wherein, n1 is the number of times the air fluid will undergo expansion due to the equal-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel; n2 is the number of times the air fluid will undergo contraction due to the equal-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel.

[0104] The following example illustrates the above design process:

[0105] Assuming the air velocity when the train passes through the tunnel is v = 30 m / s, and the air viscosity coefficient μ = 1.87 × 10⁻⁶, then...-5 Pa.s., the equivalent diameter of the buffer structure d = 14.8 m, and the calculated Reynolds number is:

[0106]

[0107] The friction coefficient λ is calculated according to formula (4), where k is the absolute roughness, and the thickness of the equal cross section is 0.8m; d is the equivalent diameter of the buffer structure, which is 14.8m. The friction coefficient λ is calculated to be 0.3.

[0108] Based on the buffer structure's length L = 30m; and the air density being 1kg / m³. 3 The pressure drop when the pressure wave passes through the buffer structure is calculated according to formula (1):

[0109]

[0110] The local drag coefficients for the sudden expansion of the cross-section are ξ1 = 0.062 and ξ2 = 0.124. Because the constant cross-section expansion buffer structure causes the airflow to undergo three expansions and three contractions, the cumulative local pressure loss ΔP... j =0.5ξ1ρv 2 n1+0.5ξ2ρv 2 n2 = 34.2 × 3 + 68.4 × 3 = 307.8 Pa. Considering that a new compression wave will be formed at the abrupt change in cross-section when the high-speed train passes through the buffer structure, a reduction factor n = 0.3 is applied to the cumulative local pressure loss. The reduction factor is an empirically determined value. This yields the final local pressure loss ΔP3 = 92.34 Pa at the constant cross-section enlarged pressure-reducing buffer structure at the high-speed railway tunnel entrance. Combining the local pressure loss and the pressure drop along the tunnel, the final pressure loss ΔP when the pressure wave passes through the constant cross-section enlarged pressure-reducing buffer structure at the high-speed railway tunnel entrance can be determined. Z =274+92.34=366.34Pa.

[0111] When a pressure wave passes through the cross-section enlarged pressure-reducing buffer structure at the entrance of a high-speed railway tunnel, it can generate a pressure drop of 366.34 Pa, indicating that the buffer structure used in this invention can effectively reduce the initial compression wave, thereby reducing the micro-pressure wave at the tunnel exit.

[0112] This invention achieves a good mitigation effect with a shorter buffer structure length. Therefore, the buffer structure occupies little longitudinal space, making full use of the stability and vegetation of the original surface at the tunnel entrance, and is less restricted by the terrain at the tunnel entrance. Furthermore, this invention uses a cast-in-place structure, which has good waterproof performance and integrity, and is not easily damaged.

[0113] Example 3

[0114] like Figure 6As shown, the construction method of the present invention for a cross-section enlarged pressure-reducing buffer structure for high-speed railway tunnel entrances further includes the following steps:

[0115] Step 1: Based on the lower dimensions of the equal cross-section enlarged section buffer structure 2, excavate a foundation pit in the foundation, tie steel bars in the foundation pit and erect formwork, and pour concrete to form the structural foundation 20 of the equal cross-section enlarged section pressure-reducing buffer structure at the entrance of the high-speed railway tunnel;

[0116] Step 2: Before the concrete of the structural foundation 20 solidifies, timely arrange the splicing reinforcement to ensure the integrity of the structural foundation 20 and its upper base plate 21.

[0117] Step 3: Tie the reinforcing bars of the base slab 21 and the standard cross-section buffer structure 3 wall reinforcement and the equal cross-section enlarged cross-section buffer structure 2 wall reinforcement at a certain height. After setting up the formwork, pour the concrete of the base slab 21 and pour the two walls at different heights, and do a good job of wall joint treatment.

[0118] Step 4: After the concrete strength of the formed base plate 21 reaches the design requirements, tie the wall reinforcement of the end of the standard cross-section tunnel 1 and the remaining wall reinforcement of the standard cross-section buffer structure 3, and erect the wall formwork. After pre-embedding the second support structure 10 and each first support structure 4 according to the design position, start pouring the wall concrete of the standard cross-section buffer structure 3.

[0119] Step 5: After the concrete of the walls of the standard cross-section tunnel 1 and each standard cross-section buffer structure 3 reaches the design strength, the formwork is erected and the remaining wall reinforcement of each equal cross-section enlarged cross-section buffer structure 2 is tied. After the second support structure 10 and each first support structure 4 are installed and fixed with the corresponding wall reinforcement of the equal cross-section enlarged cross-section buffer structure 2, the concrete is poured, and finally the equal cross-section enlarged pressure reduction buffer structure for the entrance of the high-speed railway tunnel is formed.

[0120] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-speed railway tunnel portal equal cross-section expansion type pressure reduction buffer structure, characterized in that, The equal cross-section expansion type cross-section buffer structure (2) is arranged at the end of the standard cross-section tunnel (1), is arranged at intervals along the line direction, the cross-section area of the inner cavity (16) of the equal cross-section expansion type cross-section buffer structure is greater than the cross-section area of the inner cavity (17) of the standard cross-section tunnel, the standard cross-section buffer structure (3) is arranged between adjacent equal cross-section expansion type cross-section buffer structures (2), the cross-section area of the inner cavity (18) of the standard cross-section buffer structure is less than the cross-section area of the inner cavity (16) of the equal cross-section expansion type cross-section buffer structure, and the first support structure (4) is arranged between the standard cross-section buffer structure (3) and the adjacent equal cross-section expansion type cross-section buffer structure (2); the first support structure (4) has the first curved channel (9) in the length direction of the line; The first support structure (4) comprises two rows of concrete transverse plate groups, wherein the concrete transverse plate group close to the middle position of the standard cross-section buffer structure (3) is the first concrete transverse plate group (5), and the other row of concrete transverse plate group is the second concrete transverse plate group (6); the first concrete transverse plate group (5) comprises a plurality of first concrete partitions (7) arranged at intervals in the circumferential direction of the standard cross-section buffer structure (3); the second concrete transverse plate group (6) comprises a plurality of second concrete partitions (8) arranged at intervals in the circumferential direction of the standard cross-section buffer structure (3); the first concrete partitions (7) and the second concrete partitions (8) are arranged alternately and form the first curved channel (9) in the length direction of the line.

2. The equal cross-section enlarged pressure-reducing buffer structure for a high-speed railway tunnel portal according to claim 1, characterized in that, The cross-section area of the inner cavity (18) of the standard cross-section buffer structure is greater than or equal to the cross-section area of the inner cavity (17) of the standard cross-section tunnel.

3. The equal cross-section enlarged pressure-reducing buffer structure for a high-speed railway tunnel portal according to claim 1, characterized in that, The first curved channel (9) is a Z-shaped channel or an S-shaped channel. And / or, The distance between the inner wall of the equal cross-section expansion type cross-section buffer structure (2) and the outer wall of the standard cross-section buffer structure (3) is 0.7-1 m in the radial direction of the equal cross-section expansion type cross-section buffer structure (2); And / or, The longitudinal arrangement length of the equal cross-section expansion type cross-section buffer structure (2) and the standard cross-section buffer structure (3) is 1.3-1.7 m in the length direction of the line.

4. The equal cross-section enlarged pressure-reducing buffer structure for tunnel portal of high-speed railway according to claim 1, characterized in that: The concrete of the first concrete partitions (7) and the second concrete partitions (8) is sound-absorbing concrete.

5. The equal cross-section expansion type pressure reduction buffer structure of the tunnel portal of the high-speed railway according to claim 1, wherein: The interval between adjacent first concrete partitions (7) in the first concrete transverse plate group (5) is smaller as the distance from the standard cross-section tunnel (1) is farther; And / or, The width of adjacent first concrete partitions (7) in the first concrete transverse plate group (5) in the circumferential direction of the standard cross-section buffer structure (3) is greater as the distance from the standard cross-section tunnel (1) is farther.

6. The equal cross-section enlarged pressure-reducing buffer structure for tunnel portal of high-speed railway according to claim 1, characterized in that: The second support structure (10) is arranged between the equal cross-section expansion type cross-section buffer structure (2) close to the standard cross-section tunnel (1) and the standard cross-section tunnel (1), and the second support structure (10) has the second curved channel (11) in the length direction of the line.

7. The equal cross-section enlarged pressure-reducing buffer structure for tunnel portal of high-speed railway according to claim 6, characterized in that: The second support structure (10) comprises two rows of concrete cross partition groups, wherein the concrete cross partition group far from the equal-section enlarged cross-section buffer structure (2) is a third concrete cross partition group (12), and the other row of concrete cross partition group is a fourth concrete cross partition group (13), the third concrete cross partition group (12) comprises a plurality of third concrete partitions (14) arranged along the circumference of the standard cross-section tunnel (1) at intervals, the fourth concrete cross partition group (13) comprises a plurality of fourth concrete partitions (15) arranged along the circumference of the standard cross-section tunnel (1) at intervals, the third concrete partitions (14) and the fourth concrete partitions (15) are arranged alternately and form a second curved passage (11) along the length direction of the line.

8. The equal-section enlarged cross-section pressure relief buffer structure for high-speed railway tunnel portal according to any one of claims 1-7, characterized in that: The final pressure loss value of the pressure wave passing through the pressure loss reduction and buffering structure of the cross-section expansion type of the high-speed railway tunnel portal ΔP Z Designing includes the following steps: A1, the pressure loss value of the pressure wave when passing through the cross-section expansion type pressure reduction buffer structure of the high-speed railway tunnel portal is obtained based on the axial length L of the cross-section expansion type pressure reduction buffer structure of the high-speed railway tunnel portal and the equivalent diameter d of the cross-section expansion type pressure reduction buffer structure of the high-speed railway tunnel portal ΔP ; A2, the local resistance coefficient of the cross-section sudden expansion of the equal cross-section expansion type pressure relief buffer structure of the high-speed railway tunnel portal is obtained based on the cross-section area of the equal cross-section expansion type buffer structure inner cavity (16) and the cross-section area of the standard cross-section buffer structure inner cavity (18) ξ 1 and the local resistance coefficient of the cross-section sudden contraction of the equal cross-section expansion type pressure relief buffer structure of the high-speed railway tunnel portal ξ 2; A3, local resistance coefficient based on the sudden expansion of the section of the cross-section expansion type pressure relief buffer structure of the high-speed railway tunnel portal ξ 1 and local resistance coefficient of the sudden contraction of the section of the cross-section expansion type pressure relief buffer structure of the high-speed railway tunnel portal ξ 2 obtain the cumulative local pressure loss value of the cross-section expansion type pressure relief buffer structure of the high-speed railway tunnel portal ΔP j ; A4、The cumulative local pressure loss value of the cross-section expansion type pressure reduction buffer structure of the high-speed railway tunnel portal ΔP j The final local pressure loss of the cross-section expansion type pressure reduction buffer structure of the high-speed railway tunnel portal is obtained by reduction ΔP3 ; A5, the pressure loss value when the pressure wave passes through the cross-section expansion type pressure reduction buffer structure of the high-speed railway tunnel portal Δ P the final local pressure loss of the cross-section expansion type pressure reduction buffer structure of the high-speed railway tunnel portal ΔP3 obtaining the final value of the pressure loss when the pressure wave passes through the cross-section expansion type pressure reduction buffer structure of the high-speed railway tunnel portal ΔP Z .

9. A construction method for the equal cross-section enlarged pressure-reducing buffer structure of the high-speed railway tunnel portal according to any one of claims 1-8, characterized in that, comprising the following steps: S1, excavating a foundation pit in the foundation based on the lower dimension of the equal-section enlarged cross-section buffer structure (2), and pouring concrete to form a structural foundation (20) of the equal-section enlarged cross-section pressure relief buffer structure for high-speed railway tunnel portal; S2, arranging tie-in steel bars in time before the concrete of the structural foundation (20) is solidified; S3, binding the steel bars of the bottom plate (21), the wall body steel bars of the standard cross-section buffer structure (3) of a certain height, and the wall body steel bars of the equal-section enlarged cross-section buffer structure (2) of a certain height, and pouring concrete to form the bottom plate (21), wherein the bottom plate (21) is located on the upper part of the structural foundation (20); S4, after the strength of the formed concrete of the bottom plate (21) reaches the design requirement, binding the wall body steel bars of the end part of the standard cross-section tunnel (1) and the remaining wall body steel bars of the standard cross-section buffer structure (3), and pre-burying the second support structure (10) and each first support structure (4) according to the design position, and then pouring the wall body concrete of the standard cross-section buffer structure (3) to form the standard cross-section tunnel (1) and each standard cross-section buffer structure (3); S5, after the wall body concrete of the standard cross-section tunnel (1) and each standard cross-section buffer structure (3) reaches the design strength, binding the remaining wall body steel bars of each equal-section enlarged cross-section buffer structure (2), and installing and fixing the second support structure (10) and the first support structure (4) with the wall body steel bars of the corresponding equal-section enlarged cross-section buffer structure (2), and then pouring concrete to form the equal-section enlarged cross-section buffer structure, and finally forming the equal-section enlarged cross-section pressure relief buffer structure for high-speed railway tunnel portal.

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