Road tunnel structure and construction method

Abstract

The invention discloses a road tunnel structure and a construction method, and belongs to the technical field of road tunnels. The tunnel structure comprises a passing area, and the passing area is located in the middle and achieves one-way passing. The vertical shafts are communicated with the smoke exhaust area, the number of the vertical shafts is at least 2n in the extending direction of the tunnel, the n vertical shafts supply air to the smoke exhaust area as air supply shafts, the n vertical shafts exhaust air to the outside of the tunnel as air exhaust shafts, the air supply shafts and the air exhaust shafts are alternately arranged, and in the direction from the inlet to the outlet, the first vertical shaft is the air supply shaft; a heating device is arranged in the exhaust shaft to form a top heating section, and the top heating section is close to a wellhead and heats air at the wellhead to accelerate air exhaust. The technical problem that the effect of discharging suspended particles through a fan in a vertical shaft in the high-humidity environment is poor is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of road tunnels, and in particular to a road tunnel structure and a construction method. Background Art

[0002] Tunnels are engineering structures buried in the earth and are an important form of human utilization of underground space. According to international definitions, a tunnel is a chamber with a cross-sectional area greater than two square meters constructed underground for a specific purpose. Tunnels can be categorized by their purpose as transportation tunnels (for highways, railways, and subways), hydraulic tunnels (for water diversion and drainage), municipal tunnels, and mining tunnels. Their main structure consists of a tunnel body and portals, with ancillary facilities including ventilation, lighting, and fire protection systems. Tunnels can effectively shorten travel distances and overcome geographical obstacles such as mountains, rivers, and bodies of water.

[0003] Some tunnels are built in remote, mountainous, forested, and humid areas. These narrow, long structures have poor internal air circulation. Currently, vertical shafts are commonly installed to increase air circulation within the tunnel, thereby improving ventilation efficiency. Furthermore, during construction, vertical shafts can also serve as transport channels for materials, equipment, and personnel, improving efficiency.

[0004] Due to the relatively closed interior of tunnels, vehicle exhaust, dust, and polluted air easily accumulate. Vertical shafts primarily rely on high-powered fans for air dilution and replacement, but are relatively ineffective at removing dust, pollution, and vehicle exhaust. As exhaust, dust, and polluted air accumulate within tunnels, they become suspended in the air, driven by vehicles, further reducing visibility within the already dim tunnel and increasing the risk of traffic accidents. Consequently, cleaning personnel and vehicles are required to remove these pollutants. However, due to tunnel conditions, cleaning frequency is infrequent, effectiveness is limited, and significant labor and material resources are consumed.

[0005] If the cleaning effect is improved by increasing the fan power, the improvement is not obvious, and the operating energy consumption is high. It may also generate low-frequency noise that affects the surrounding environment. The particulate matter suspended in the tunnel is mainly fine particulate matter. Fine particles may be separated from the mainstream direction due to the turbulence generated by the fan in the negative pressure area of ​​the shaft, and then re-suspended in the tunnel. In addition, in a high-humidity environment, the surface of the fan blades is prone to condensation to form a large number of water droplets, which will destroy the original aerodynamic shape of the blades, affect the rotation of the fan, and further interfere with the fan's cleaning effect on suspended particles. At the same time, a high-humidity environment is prone to corrosion and loss of components such as motors and blades. In addition, suspended particles inevitably pass through the fan during the discharge process, and the rotating blades will block the discharge of suspended particles. For this reason, a tunnel structure is proposed to solve the technical problem of poor effect of using fans to discharge suspended particles in shafts under high humidity environments. Summary of the Invention

[0006] The main purpose of the present invention is to provide a road tunnel structure, aiming to solve the technical problem that vertical shafts are difficult to vent in high humidity environments.

[0007] To achieve the above-mentioned objectives, the present invention proposes a road tunnel structure having an entrance and an exit, including: A traffic area, which is located in the middle and is one-way; Vertical shafts, the vertical shafts being connected to the passage area, and at least 2n vertical shafts being provided along the extension direction of the tunnel, wherein n vertical shafts are used to supply air into the passage area and are referred to as air supply shafts, and the other n vertical shafts are used to exhaust air out of the tunnel and are referred to as air exhaust shafts, the air supply shafts and the air exhaust shafts being provided alternately, and the first vertical shaft from the entrance to the exit is the air supply shaft; A heating device is provided in the exhaust shaft, and the heating device includes a top heating section. The top heating section is arranged close to the top wellhead and circumferentially arranged in the wall of the exhaust shaft. The top heating section is energized to heat the air in the top wellhead, so that the heat density of the wellhead air decreases, thereby increasing the buoyancy speed, so as to form a thermal negative pressure zone at the top wellhead to accelerate the rise of suspended particulate matter in the tunnel.

[0008] Optionally, in one embodiment of the present invention, the exhaust shaft is a variable diameter structure, the overall depth of the exhaust shaft is L, the exhaust shaft includes an upper section with a depth of 1 / 3L and a lower section with a depth of 2 / 3L, the diameter of the upper section is smaller than the diameter of the lower section, and the exhaust shaft is variable in diameter so that the air flow in the exhaust shaft forms turbulence to destroy thermal stratification.

[0009] Optionally, in one embodiment of the present invention, the heating device further includes a middle heating section and a bottom well heating section, the middle heating section is located in the middle of the exhaust shaft, and the bottom well heating section is located at the bottom of the exhaust shaft. From the bottom of the well to the wellhead, the temperatures of the three heating sections increase successively.

[0010] Optionally, in one embodiment of the present invention, the heating temperature range of the bottom hole heating section is 32-35°C; The heating temperature range of the middle heating section is 48~52℃; The heating temperature range of the top heating section is 65~68℃.

[0011] Optionally, in one embodiment of the present invention, the vertical shaft further includes a spiral guide plate, the angle of the spiral guide plate is 40°~45°, the spiral guide plate in the exhaust shaft rotates counterclockwise, a fan is arranged in the supply air shaft, and the rotation direction of the spiral guide plate in the supply air shaft is the same as the rotation direction of the fan.

[0012] Optionally, in one embodiment of the present invention, the spiral guide plate in the exhaust shaft includes a first spiral guide plate and a second spiral guide plate, the first spiral guide plate is located between the top heating section and the middle heating section, the pitch of the first spiral guide plate is 40mm~45mm, the second spiral guide plate is located between the middle heating section and the bottom heating section, the pitch of the second spiral guide plate is 30mm~35mm.

[0013] The present invention further provides a tunnel construction method, which is applied to the tunnel structure described above, comprising: S1. Mark the shaft position according to the design drawings, excavate to form a foundation pit, and lay mortar at the bottom of the foundation pit; S2, blasting construction in the depth direction of the shaft; S3. When the tunnel face height reaches 1.5m, the steel corrugated plate construction is carried out; S4. When the height of the steel corrugated plate reaches 3m~6m, the steel bars are bound and then the integral telescopic formwork is used for construction; S5. After the slipform is lowered, pour concrete between the formwork and the steel corrugated plate; S6. Repeat steps S2 to S5 until the shaft reaches the designed depth; S7, tunnel construction, connecting shafts; S8. A groove is opened inside the exhaust shaft, a heating device and a spiral guide plate are arranged, and a fan is installed in the supply shaft.

[0014] Optionally, in one embodiment of the present invention, step S3 includes: S31, first construct the positioning anchor rods of the steel corrugated plate, and then assemble the steel corrugated plate; S32. Install a rubber water stop strip between two adjacent steel corrugated plates; S33. Carry out grouting backfill on the steel corrugated plate wall.

[0015] Optionally, in one embodiment of the present invention, step S2 includes: S21, tie the steel bars and bury the reserved holes for the advanced pipe shed; S22, pouring concrete, backfilling the well area with rubble concrete, and placing the advanced pipe shed at the corresponding intervals and pouring; S23. Measure and lay out the wellbore centerline, measure and lay out the blasthole positions, and drill blastholes based on the blasthole positions; S24, placing water gel explosives in the blasting hole and performing blasting; S25. After blasting, use a rock grabber to remove the blasting debris and drain the water at the bottom of the well after the debris is cleared.

[0016] Compared with existing technologies, the present invention achieves at least the following beneficial effects. This solution employs at least two vertical shafts, one near the tunnel entrance and the other near the tunnel exit. The shaft near the tunnel entrance serves as the air supply shaft, while the other serves as the exhaust shaft. This creates a circulation system between the two shafts, the traffic area, and the external environment. Fresh air enters the traffic area through the supply shaft and gradually diffuses throughout the tunnel. Exhaust gases emitted by vehicles during operation are discharged through the exhaust shaft to the outside, completing the air circulation within the tunnel.

[0017] In order to discharge the suspended particles in the tunnel, the wellhead of the exhaust shaft is heated. After the wellhead is heated, the air at the wellhead heats up, the density of the high-temperature air decreases, and the rate of upward movement is faster than that of the low-temperature gas, which accelerates the upward flow of the air in the exhaust shaft. When the air is discharged, the suspended particles are discharged synchronously. Since the air flow speed at the wellhead of the exhaust shaft is faster, a stable thermal negative pressure zone will be formed at the wellhead. A stronger air pressure gradient will be generated inside the exhaust shaft and between the exhaust shaft and the air supply shaft, which accelerates the overall air circulation rate under the drive of the thermal negative pressure. In addition, the heating device in this solution is arranged inside the well wall, which will not hinder the movement of suspended particles. In this solution, the exhaust efficiency of the exhaust shaft is accelerated by heating the wellhead of the exhaust shaft. At the same time, this method is less affected by the environmental humidity, thereby solving the technical problem that the use of fans to discharge suspended particles in vertical shafts under high humidity environments is poor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0019] Figure 1 This is a schematic cross-sectional view of an embodiment of a road tunnel structure according to the present invention; Figure 2 This is a schematic diagram of an axial cross-sectional structure of an embodiment of a road tunnel structure of the present invention; Figure 3 This is a schematic structural diagram of an exhaust shaft in a tunnel structure of the present invention; Figure 4 This is a flow chart of an embodiment of a tunnel construction method according to the present invention.

[0020] Description of Figure Numbers: 110, passage area; 120, smoke exhaust area; 130, evacuation passage; 200, vertical shaft; 210, air supply shaft; 220, exhaust shaft; 221, top heating section; 222, middle heating section; 223, bottom heating section; 224, radiator; 225, solar panel; 226, electric heater; 300, spiral guide plate; 310, first spiral guide plate; 320, second spiral guide plate; The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0022] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0023] In the present invention, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0024] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0025] Reference Figures 1 to 3 The present invention provides a road tunnel structure having an entrance and an exit, comprising: A traffic area 110, which is located in the middle and is one-way; Vertical shafts 200, each connected to the passage area 110. At least 2n vertical shafts 200 are provided along the extension direction of the tunnel, wherein n vertical shafts 200 supply air into the passage area 110 as supply shafts 210, and the other n vertical shafts 200 exhaust air out of the tunnel as exhaust shafts 220. The supply shafts 210 and the exhaust shafts 220 are alternately provided. In the direction from the entrance to the exit, the first vertical shaft 200 is the supply shaft 210; A heating device is provided in the exhaust shaft 220, and the heating device includes a top heating section 221. The top heating section 221 is arranged close to the top wellhead and circumferentially arranged in the wall of the exhaust shaft 220. The top heating section 221 is energized to heat the air in the top wellhead, so that the heat density of the wellhead air decreases, thereby increasing the buoyancy speed, so as to form a thermal negative pressure zone at the top wellhead to accelerate the rise of suspended particulate matter in the tunnel.

[0026] In this solution, at least two vertical shafts 200 are provided, one near the tunnel entrance and the other near the tunnel exit. The shaft 200 near the tunnel entrance serves as an air supply shaft 210, while the other serves as an exhaust shaft 220. A circulation system is established between these two shafts 200, the passage area 110, and the external environment. Fresh air enters the passage area 110 through the air supply shaft 210 and gradually diffuses throughout the tunnel through the smoke vent. Exhaust gas emitted by vehicles during operation enters the passage area 110 through the smoke vent and is discharged to the outside through the exhaust shaft 220, completing the air circulation within the tunnel.

[0027] In order to improve the efficiency of air circulation, the wellhead of the exhaust shaft 220 is heated. After the wellhead is heated, the air at the wellhead increases in temperature, and the density of the high-temperature air decreases (ρ∝1 / T). Compared with the lower-temperature gas, the high-temperature air moves upward at a faster rate, accelerating the outflow of air from the exhaust shaft 220. At the same time, due to the faster air flow rate at the wellhead of the exhaust shaft 220, a stable negative pressure zone is formed at the wellhead. A stronger pressure gradient is generated inside the exhaust shaft 220 and between the exhaust shaft 220 and the air supply shaft 210. Driven by the negative pressure, the overall air circulation rate is accelerated, forming a synergistic "push-pull effect" that enhances global air circulation, thereby further improving the air circulation efficiency inside the tunnel. Specifically, the air pressure at the wellhead of the exhaust shaft 220 is lower than the air pressure inside the tunnel, thereby promoting the airflow in the tunnel to flow to the exhaust shaft 220, which is discharged from the exhaust shaft 220 to the external environment while preventing external airflow backflow.

[0028] In addition, the exhaust of air in the exhaust shaft can be accelerated by heating the wellhead. This method is less affected by the environment. In a high-humidity environment, it has better exhaust effect than a fan and requires less maintenance.

[0029] Furthermore, because high-temperature air tends to flow upward more easily within the exhaust shaft 220, temperature stratification is more likely to occur in deeper exhaust shafts 220. The air temperature stratification phenomenon within the tunnel exhaust shaft 200 can significantly affect the normal circulation of air. First, temperature stratification causes the cold and hot air to form a layered structure due to density differences. When cold air accumulates in the lower layer, it blocks the natural upward path of the hot air, increasing airflow resistance and reducing the effective ventilation area, significantly reducing exhaust efficiency. Second, the stratification phenomenon can trigger a temperature inversion effect at the bottom of the shaft 200. The cold air layer acts as a barrier, inhibiting the vertical diffusion of pollutants, causing harmful gases such as carbon monoxide to accumulate in the middle and lower parts, creating a risk of stagnation and threatening the tunnel environment. More seriously, temperature stratification disrupts the continuous temperature difference distribution inside and outside the shaft 200, rendering the natural ventilation mechanism that relies on the thermal pressure effect ineffective. The cold air layer blocks the upward path of the hot air, making it difficult to form a "chimney effect" and significantly weakening the natural ventilation capacity.

[0030] To address the temperature stratification within the exhaust shaft 200, the shaft is designed with a variable diameter structure. This variable diameter structure forces a sudden change in airflow velocity by changing its cross-sectional area. This creates shear layers and vortices at the variable diameter point, disrupting the previously stable thermal stratification interface and further accelerating the outflow of air from the shaft.

[0031] Furthermore, a central heating section 222 and a bottom heating section 223 are provided in the exhaust shaft 200. The central heating section 222 heats the air in the central portion of the exhaust shaft 200, accelerating air flow and further disrupting temperature stratification through localized high temperatures. The localized high-temperature zone created by the central heating section 222 in the central portion of the exhaust shaft 200 induces airflow expansion and sudden velocity changes, generating turbulence that disrupts the laminar boundary layer, thereby reducing or eliminating temperature stratification.

[0032] Furthermore, the bottom heating section 223 heats the air at the bottom of the exhaust shaft 200 to further improve the air circulation efficiency.

[0033] The lower-temperature area at the bottom of the well is initially heated by the bottom-of-well heating section 223, creating a base temperature rise. The temperature in the middle rises further, and the air expands due to continued heat, further reducing its density. The wellhead section is then concentratedly heated to a higher temperature, maximizing the air density difference inside and outside the shaft 200 and creating a dramatic chimney effect. This stepped temperature layout not only avoids energy decay at a single heat source but also creates a continuous thermal pressure gradient from the bottom of the well to the wellhead, providing kinetic energy replenishment through step-by-step acceleration of the airflow, achieving a superimposed enhancement effect similar to a "thermal booster."

[0034] Secondly, the design addresses the inherent flaws of traditional exhaust systems by optimizing flow field stability. The multi-stage temperature rise generated by segmented heating effectively breaks down the thermal stratification that easily forms during the ascent of high-heat airflow, reducing the disordered mixing of cold air and hot flue gas. Simultaneously, the high-speed airflow boundary layer formed by high-temperature acceleration at the wellhead section suppresses the "suck-through" effect caused by pressure imbalance in the lower cold air. The bottomhole preheating stage completes primary energy input, the central heat source activates secondary energy, and the high-temperature section at the wellhead directly converts thermal energy into kinetic energy output, forming a three-stage energy synergy path of "preheating-energy replenishment-enhancement."

[0035] Specifically, the selection of the heating method is explained by taking the design of three heating sections in the exhaust shaft 200 as an example.

[0036] Optionally, the top heating section 221 , the middle heating section 222 and the bottom heating section 223 may all be equipped with electric heaters 226 to increase the temperature of the air in the shaft 200 .

[0037] Preferably, since the top heating section 221 is close to the wellhead, a combination of a solar panel 225 and a radiator 224 can be selected to realize the heating function of the top heating section 221. The solar panel 225 absorbs heat to heat the circulating medium, and the high-temperature circulating medium is pumped to the radiator 224 through a pump. The radiator 224 disperses the temperature of the high-temperature medium to the wellhead, thereby realizing temperature increase at the wellhead of the exhaust shaft 220.

[0038] While the top heating section 221 utilizes solar energy for heating, the middle heating section 222 and the bottom heating section 223 still utilize electric heaters to heat the air. Since the tunnel shaft 200 is typically over 200 meters deep, using the same heating structure of solar panels 225 and radiators 224 in both the middle heating section 222 and the bottom heating section 223 would require a higher pump head and result in higher operating costs. Therefore, it is preferred to utilize electric heaters 226 to heat the middle and bottom portions of the shaft 200.

[0039] In addition, the radiator 224 and the electric heater 226 are complementary in design, taking into account the advantages of both passive and active heating. The radiator 224 can utilize ambient heat for a long time to achieve low-energy operation, while the electric heater 226 can provide rapid response capabilities and flexibly respond to emergency smoke exhaust or dynamic adjustment needs.

[0040] Optionally, multiple solar panels 225 can be provided ( Figure 2 The solar panels 225 are for illustration only and do not limit the number of solar panels 225). Some solar panels 225 are used to heat the wellhead portion of the exhaust shaft 220, and some solar panels 225 are used to supply energy to the middle heating section 222 and the bottom heating section 223.

[0041] Of course, when the depth of the shaft 200 is shallow and the pump head is easily satisfied, the middle heating section 222 and the bottom heating section 223 can also choose a structure in which the radiator 224 is connected to the solar panel 225 for heating, and the medium circulation is completed by the pump.

[0042] Specifically, the type of the radiator 224 can be a finned tube radiator 224 or a heat pipe radiator 224, etc. The electric heater 226 can be a PTC ceramic electric heater or a stainless steel armored electric heating tube, etc.

[0043] Different heating schemes can be selected for different application environments. For example, in an application scenario with good natural ventilation, only the top heating section 221 can be turned on for wellhead heating, while in an application scenario with poor natural ventilation, all heating sections can be turned on.

[0044] In addition, the heating temperatures of the three heating sections decrease in sequence from the wellhead to the bottom of the well.

[0045] In this solution, no fans are installed in the exhaust shaft 220. This solution can improve ventilation efficiency in fan-free conditions by enhancing the thermal pressure effect. Specifically, the top heating section 221 at the wellhead heats the air at the highest temperature, significantly reducing the air density at the top and forming a strong core driving force for the upward airflow. Based on the thermal pressure formula (ρ∝1 / T), the overall average temperature difference ΔT between the inside and outside of the vertical shaft 200 is increased through a gradient temperature difference, thereby enhancing the thermal pressure driving force and driving a larger air volume. At the same time, the layered design, in which the temperature decreases from top to bottom, aligns with the bottom-up direction of the airflow, avoiding turbulent disturbances caused by the backflow of cold air from the wellhead and suppressing the sinking trend of cold air at the bottom due to density differences, maintaining the unidirectional stability of the airflow and reducing flow resistance. In terms of energy efficiency, the design concentrates the main energy on the top area that contributes most to ventilation through differentiated heating power distribution, reducing the energy consumption of ineffective heating at the bottom. At the same time, it can dynamically adjust the heating intensity of each section according to seasonal ambient temperature changes. For example, in winter, the low temperature environment is used to amplify the thermal pressure effect, and in summer, the heating power is appropriately reduced to achieve energy-saving optimization.

[0046] Preferably, the top heating section 221 needs to heat the air temperature at the wellhead of the exhaust shaft 220 to 65-68°C; The middle heating section 222 needs to heat the air temperature in the middle of the exhaust shaft 220 to 48~52℃; The bottom well heating section 223 needs to heat the air temperature at the bottom of the exhaust well 220 to 32~35℃.

[0047] Since the heating capacity of solar panels is slightly lower than that of electric heaters, the above-mentioned heating temperature range selection is the temperature selection under the conditions of using radiators and solar panels in the top heating section.

[0048] The top heating section 221 has the highest temperature, forming the top high-temperature section. The air density at the wellhead decreases dramatically after being heated, forming a core of high-speed rising airflow. This generates a strong negative pressure suction force, driving the air below to continuously rise. When the wellhead air temperature is 68°C and the ambient temperature is 20°C, ΔT = 48°C. Compared to the unheated condition, the thermal pressure difference increases by approximately 16%, significantly improving wellhead air flow.

[0049] The temperature of the bottom hole heating section 223 is the lowest, forming a bottom hole low temperature section, where the temperature is slightly higher than the ambient temperature, which can prevent cold air from accumulating at the bottom of the well to form a dead zone.

[0050] The middle heating section 222 has a moderate temperature, forming a central transition section. The temperature and location of the middle heating section 222 lie between the top heating section 221 and the bottom heating section 223, creating a gradual temperature gradient within the exhaust shaft 220. This prevents large differences in air density caused by sudden temperature changes, thereby reducing interlayer turbulence or localized eddies. Furthermore, in longer exhaust shafts 220, temperature stratification is prone to occur in the middle of the shaft, impacting air flow. The presence of the middle heating section 222 can also help break down these temperature stratifications.

[0051] In this solution, the temperature field that decreases from top to bottom (68°C → 52°C → 35°C) and the direction of air flow in the exhaust shaft 220 can reduce the risk of turbulence or backflow caused by sudden changes in density between air layers.

[0052] Specifically, grooves are evenly spaced along the circumferential direction on the inner wall of the exhaust shaft 220 , and the radiator 224 and the electric heater 226 are placed in the grooves so that they do not protrude from the inner wall of the exhaust shaft 220 .

[0053] This structure can improve exhaust efficiency and optimize system stability. The groove design can keep the inner wall of the exhaust shaft 220 streamlined, reduce airflow turbulence and local resistance, avoid heat loss, and reduce the obstruction of such auxiliary components to air flow.

[0054] In order to further increase the air circulation speed of the entire tunnel, spiral guide plates 300 are provided in both the air supply shaft 210 and the air exhaust shaft 220 .

[0055] The spiral guide plates 300 rectify the air flow. After the air in the shaft 200 passes through the spiral guide plates 300, the chaotic turbulent flow is transformed into stable spiral laminar flow, reducing the impact of the airflow with the shaft wall, thereby reducing energy loss and improving ventilation efficiency. Furthermore, after the air flows through the spiral guide plates 300, it imparts a rotational inertial force to the airflow, accelerating its velocity and preventing backflow, thus achieving stable tunnel air circulation.

[0056] Because the air supply shaft 210 needs to deliver external air into the tunnel, a fan is required to extract and pump external air into the tunnel. To this end, when the spiral guide plate 300 is provided, the spiral guide plate 300 rotates in the same direction as the fan. Generally, the fan in the air supply shaft 210 rotates clockwise to reduce impact losses when air enters the spiral guide plate 300 and improve the air intake efficiency of the air supply shaft 210. Specifically, one or more spiral guide plates 300 may be provided in the air supply shaft 210.

[0057] Exhaust is achieved in the exhaust shaft 220 through heating and natural flow of air. The spiral guide plate 300 in the exhaust shaft 220 is preferably designed to rotate counterclockwise, which guides the turbid air to rise along a spiral path. At the same time, a push-pull effect of air circulation can be formed between the counterclockwise rotating spiral guide plate 300 in the exhaust shaft 220 and the clockwise rotating spiral guide plate 300 in the supply shaft 210, thereby promoting the directional flow of air in the tunnel, reducing air short circuits or air dead corners, and improving the overall circulation efficiency.

[0058] Specifically, the angle of the spiral guide plates 300 in both the supply shaft 210 and the exhaust shaft 220 is designed to be 40° to 45°. This angle not only guides the airflow into a stable spiral motion, but also avoids flow separation (turbulence caused by the airflow separating from the spiral guide plates 300) caused by excessively large angles. This reduces energy loss caused by airflow striking the shaft walls while maintaining low resistance along the way, optimizing ventilation efficiency.

[0059] When the inclination angle of the spiral guide plate 300 is less than 40°, the central recirculation phenomenon of the spiral guide plate 300 has a more obvious impact on the air circulation. When the inclination angle of the spiral guide plate 300 exceeds 45°, the secondary vortex phenomenon is more significant and the circulation stability is poor.

[0060] Preferably, the inclination angle of the spiral guide plate 300 can be selected to be 43°. Although the inclination angle of 43° has central reflux, it has little impact on air circulation and has better airflow circulation stability. Since the environment inside the shaft 200 is relatively harsh and operation is inconvenient, the stability of the use of the spiral guide plate 300 also needs to be considered. This angle design can make the force on the spiral guide plate 300 more uniform and extend the life of the material. At the same time, this inclination angle can reduce the adhesion of dust on the surface of the spiral guide plate 300.

[0061] In the exhaust shaft 220, since there are three heating sections, it is preferred that at least two spiral guide plates 300 are provided, namely the first spiral guide plate 310 and the second spiral guide plate 320, wherein the first spiral guide plate 310 is located between the top heating section 221 and the middle heating section 222, and the second spiral guide plate 320 is located between the middle heating section 222 and the bottom heating section 223.

[0062] When the turbid air in the exhaust shaft 220 moves from the bottom of the well to the wellhead, it is first heated by the bottom heating section 223, the density decreases, and the rising speed increases, and then passes through the second spiral guide plate 320, further shortening its rising time. Similarly, the first spiral guide plate 310 can also shorten the time for the air in the middle heating section 222 to move to the top heating section 221.

[0063] Furthermore, the pitch of the first spiral guide plate 310 is larger than the pitch of the second spiral guide plate 320. Specifically, the pitch of the first spiral guide plate 310 is 40 mm to 45 mm, and the pitch of the second spiral guide plate 320 is 30 mm to 35 mm.

[0064] The high-temperature zone formed by the top heating section 221 generates strong upward momentum due to its high temperature and low density. The large-pitch spiral guide vanes 300 reduce rotational resistance, accelerating the rapid ascent of the high-temperature airflow and maximizing the thermal pressure effect. Secondly, in the middle and lower temperature zones formed by the bottom heating section 223, the thermal pressure force weakens due to decreasing temperature. Small-pitch guide vanes enhance centrifugal force, forcing the medium- and low-temperature airflow to spiral upward along the wall, inhibiting the sinking of cold air or lateral mixing, and maintaining flow continuity.

[0065] The coordinated design of the deflector pitch and temperature gradient creates a "layered spiral" path within exhaust shaft 220, reducing heat exchange between airflows at different temperature zones and lowering energy dissipation. Simultaneously, the high pitch of the upper layer accommodates high-speed airflow, while the low pitch of the lower layer accommodates low-speed airflow, dynamically balancing speed and rotational momentum. Furthermore, the low-pitch deflector enhances centrifugal force in the low-temperature zone at the bottom of the shaft, suppressing cold air backflow and vortex formation, further ensuring exhaust stability.

[0066] In order to further improve the exhaust efficiency of the exhaust shaft 220, a deflector can be set at the wellhead of the exhaust shaft 220. Specifically, the deflector is a streamlined structure with a gradually expanding trumpet shape, and the deflector gradually expands from the wellhead to 1.2 to 1.5 times the diameter of the vertical shaft 200.

[0067] In addition to improving natural ventilation, the solution can also speed up smoke extraction in fire environments.

[0068] The gradient heating system also expels smoke from the tunnel more quickly in fire scenarios. Continuous high-temperature heating at the top reduces heat loss from smoke entering shaft 200, preventing it from settling due to cooling and densification, ensuring its continued upward movement and discharge. The stable temperature gradient also inhibits lateral diffusion of smoke within shaft 200, creating a directional suction effect in conjunction with the exhaust duct, thereby improving smoke exhaust efficiency and the safety of escape routes. This multi-level heating strategy not only efficiently drives natural ventilation but also strikes a balance between energy conservation and disaster resilience.

[0069] In addition, refer to Figure 1 In addition to the traffic area 110, the proposed road tunnel structure also features a smoke exhaust area 120. An evacuation passage 130 is also designed beneath traffic area 110 for evacuating personnel in emergencies such as fires. Considering the ventilation requirements of the emergency evacuation area and balancing ventilation efficiency and space utilization, the cross-sectional area of ​​smoke exhaust area 120 is preferably 10% to 15% of the total tunnel cross-sectional area.

[0070] Specifically, the smoke exhaust area 120 and the passage area 110 may be connected via a smoke outlet, and the intervals between the smoke outlets may be adjusted according to the number of vertical shafts 200 provided.

[0071] Reference Figure 4 The present invention also proposes a tunnel construction method, which is applied to the tunnel structure described above. Specifically, the construction method includes: S1. Mark the position of the vertical shaft 200 according to the design drawings, excavate to form a foundation pit, and lay mortar at the bottom of the foundation pit; S2, blasting construction at a depth of 200 in the vertical shaft; S3. When the tunnel face height reaches 1.5m, the steel corrugated plate construction is carried out; S4. When the height of the steel corrugated plate reaches 3m~6m, the steel bars are bound and then the integral telescopic formwork is used for construction; S5. After the slipform is lowered, pour concrete between the formwork and the steel corrugated plate; S6. Repeat steps S2 to S5 until the shaft 200 reaches the designed depth; S7, tunnel construction, connecting shaft 200; S8. A groove is opened inside the exhaust shaft 220, a heating device and a spiral guide plate 300 are arranged, and a fan is installed in the supply shaft 210.

[0072] Whether it is the tunnel main body or the vertical shaft 200, during the construction process, it is necessary to set the corresponding construction process according to the hardness of the rock in the construction area. If the surrounding rock in the construction area is relatively fragile, then during the construction process, after excavation, the exposed surface is prone to local peeling, falling blocks or even collapse due to stress release or groundwater infiltration, resulting in the inability to construct the vertical shaft 200 to ventilate the tunnel.

[0073] In this construction method, after the foundation pit is excavated, mortar is laid at the bottom of the foundation pit to level the base, isolate groundwater and protect the foundation, providing a stable and flat foundation for the subsequent construction of the shaft 200 structure.

[0074] Blasting is used to expand downward, and whenever the blasting reaches 1.5 meters below the tunnel face, steel corrugated plates are installed. After excavation of the tunnel face, stresses in the surrounding rock and soil are redistributed, especially in the fragile surrounding rock. The exposed surface at a height of 1.5 meters is close to the self-stabilization limit of the surrounding rock. At this time, steel corrugated plates are needed to quickly provide radial support to the exposed surface to prevent accumulated deformation and cascading instability.

[0075] When the length of the steel corrugated plates reaches 3 to 6 meters, multiple groups of steel corrugated plates are bound with steel bars, and concrete is poured between the slipforms and the steel corrugated plates through slipform construction to form the wall of the shaft 200. After the concrete is poured, the wall structure is more stable and has a stronger bearing capacity, ensuring the stability of the excavated depth.

[0076] When the vertical shaft 200 is constructed to the designed depth, the main body of the tunnel is constructed, and the main body of the tunnel is connected to the vertical shaft 200, and air is supplied to the tunnel construction area through the vertical shaft 200.

[0077] After the construction of the tunnel body and the shaft 200 is completed, a fan and a spiral guide plate 300 are arranged in the air supply shaft 210 so that external air can be sent into the tunnel. A groove is opened inside the exhaust shaft 220, and the radiator 224 and the electric heater 226 are placed in the groove. The spiral guide plate 300 is arranged so that the air inside the tunnel can be discharged to the outside.

[0078] Furthermore, step S3 includes: S31, first construct the positioning anchor rods of the steel corrugated plate, and then assemble the steel corrugated plate; S32. Install a rubber water stop strip between two adjacent steel corrugated plates; S33. Carry out grouting backfill on the steel corrugated plate wall.

[0079] In this process, after the tunnel face is constructed to a height of 1.5m, anchor bolts corresponding to the steel corrugated panels are installed on the tunnel face before supporting them. This ensures accurate installation of the panels. During installation, gaps exist between adjacent panels, and rubber waterstops are used to prevent subsequent water seepage. After the steel corrugated panels are supported, grouting backfill is also required to ensure stable support.

[0080] Furthermore, step S2 includes: S21, tie the steel bars and bury the reserved holes for the advanced pipe shed; S22, pouring concrete, backfilling the well area with rubble concrete, and placing the advanced pipe shed at the corresponding intervals and pouring; S23. Measure and lay out the wellbore centerline, measure and lay out the blasthole positions, and drill blastholes based on the blasthole positions; S24, placing water gel explosives in the blasting hole and performing blasting; S25. After blasting, use a rock grabber to remove the blasting debris and drain the water at the bottom of the well after the debris is cleared.

[0081] In construction environments with fragile surrounding rock, advanced support is used to prevent rock instability. Advanced pipe sheds, pre-installed with steel pipes through pre-drilled holes, form a support framework to prevent collapse or falling blocks caused by stress release after excavation. The pre-drilled holes provide a precise path for subsequent grouting. Grout diffuses through the pipe shed, filling cracks and cementing loose rock and soil, significantly improving the bearing capacity and impermeability of the surrounding rock.

[0082] The combined effect of the advanced pipe roof and grouting creates a "rigid beam" effect, which inhibits the transmission of surrounding rock deformation to the surface and avoids cracking of surrounding buildings or damage to pipelines.

[0083] Water-gel explosives are used for blasting. Compared to traditional explosives (such as ammonium nitrate-fuel oil), water-gel explosives release energy more evenly, avoiding excessive impact of instantaneous high pressure on the surrounding rock, reducing crack expansion and the extent of the loosening zone. The initial shock wave pressure generated by the explosion is lower, which can reduce vibration damage to the surrounding rock and avoid causing landslides.

[0084] The above descriptions are merely optional embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present description and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A road tunnel structure having an entrance and an exit, characterized in that: include: A traffic area, which is located in the middle and is one-way; Vertical shafts, the vertical shafts being connected to the passage area, and at least 2n vertical shafts being provided along the extension direction of the tunnel, wherein n vertical shafts are used to supply air into the passage area and are referred to as air supply shafts, and the other n vertical shafts are used to exhaust air out of the tunnel and are referred to as air exhaust shafts, the air supply shafts and the air exhaust shafts being provided alternately, and the first vertical shaft from the entrance to the exit is the air supply shaft; A heating device is provided in the exhaust shaft, and the heating device includes a top heating section. The top heating section is arranged close to the top wellhead and circumferentially arranged in the wall of the exhaust shaft. The top heating section is energized to heat the air in the top wellhead, so that the heat density of the wellhead air decreases, thereby increasing the buoyancy speed, so as to form a thermal negative pressure zone at the top wellhead to accelerate the rise of suspended particulate matter in the tunnel.

2. The tunnel structure according to claim 1, characterized in that: The exhaust shaft is a variable diameter structure, and the overall depth of the exhaust shaft is L. The exhaust shaft includes an upper section with a depth of 1 / 3L and a lower section with a depth of 2 / 3L. The diameter of the upper section is smaller than the diameter of the lower section. The variable diameter of the exhaust shaft causes the airflow in the exhaust shaft to form turbulence and destroy thermal stratification.

3. The tunnel structure according to claim 2, characterized in that: The heating device also includes a middle heating section and a bottom well heating section. The middle heating section is located in the middle of the exhaust shaft, and the bottom well heating section is located at the bottom of the exhaust shaft. From the bottom of the well to the wellhead, the temperatures of the three heating sections increase successively.

4. The tunnel structure according to claim 3, characterized in that: The heating temperature range of the bottom hole heating section is 32~35℃; The heating temperature range of the middle heating section is 48~52℃; The heating temperature range of the top heating section is 65~68℃.

5. The tunnel structure according to claim 3, characterized in that: The vertical shaft also includes a spiral guide plate, the angle of the spiral guide plate is 40°~45°, the spiral guide plate in the exhaust shaft rotates counterclockwise, a fan is installed in the air supply shaft, and the rotation direction of the spiral guide plate in the air supply shaft is the same as the rotation direction of the fan.

6. The tunnel structure according to claim 5, characterized in that: The spiral guide plate in the exhaust shaft includes a first spiral guide plate and a second spiral guide plate. The first spiral guide plate is located between the top heating section and the middle heating section, and the pitch of the first spiral guide plate is 40mm~45mm. The second spiral guide plate is located between the middle heating section and the bottom heating section, and the pitch of the second spiral guide plate is 30mm~35mm.

7. A tunnel construction method, applied to the tunnel structure according to any one of claims 1 to 6, characterized in that: include: S1. Mark the shaft position according to the design drawings, excavate to form a foundation pit, and lay mortar at the bottom of the foundation pit; S2, blasting construction in the depth direction of the shaft; S3. When the tunnel face height reaches 1.5m, the steel corrugated plate construction is carried out; S4. When the height of the steel corrugated plate reaches 3m~6m, the steel bars are bound and then the integral telescopic formwork is used for construction; S5. After the slipform is lowered, pour concrete between the formwork and the steel corrugated plate; S6. Repeat steps S2 to S5 until the shaft reaches the designed depth; S7, tunnel construction, connecting shafts; S8. A groove is opened inside the exhaust shaft, a heating device and a spiral guide plate are arranged, and a fan is installed in the supply shaft.

8. The tunnel construction method according to claim 7, characterized in that: Step S3 includes: S31, first construct the positioning anchor rods of the steel corrugated plate, and then assemble the steel corrugated plate; S32. Install a rubber water stop strip between two adjacent steel corrugated plates; S33. Carry out grouting backfill on the steel corrugated plate wall.

9. The tunnel construction method according to claim 8, characterized in that: Step S2 includes: S21, tie the steel bars and bury the reserved holes for the advanced pipe shed; S22, pouring concrete, backfilling the well area with rubble concrete, and placing the advanced pipe shed at the corresponding intervals and pouring; S23. Measure and lay out the wellbore centerline, measure and lay out the blasthole positions, and drill blastholes based on the blasthole positions; S24, placing water gel explosives in the blasting hole and performing blasting; S25. After blasting, use a rock grabber to remove the blasting debris and drain the water at the bottom of the well after the debris is cleared.

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