Tunnel anti-slope negative pressure siphon drainage method and device

Abstract

The application provides a tunnel anti-slope negative pressure siphon drainage method and device, and belongs to the technical field of building construction. The method comprises the following steps: S1: connecting a water collecting pit in a tunnel body with a negative pressure chamber in a water absorption tank; and S2: using a negative pressure siphon principle to absorb water in the water collecting pit into the negative pressure chamber, and draining the water absorbed in the negative pressure chamber into an upper water collecting chamber; when the water level h in the upper water collecting chamber reaches a critical water level h0, the gravity of the water in the upper water collecting chamber overcomes the supporting force of an elastic partition valve to open the elastic partition valve, at this time, the upper water collecting chamber is connected with a lower water collecting chamber, and the water in the upper water collecting chamber is drained into the lower water collecting chamber. Under the action of constant negative pressure absorption of the negative pressure chamber, the water in the water collecting pit can be completely absorbed, the drainage efficiency is improved, and the construction progress and construction quality are improved.

Description

Technical Field

[0001] This invention belongs to the field of building construction technology and relates to drainage technology in construction tunnels, specifically a method and device for tunnel reverse slope negative pressure siphon drainage. Background Technology

[0002] In mountain tunnel construction, for medium and short tunnels (highway tunnels <1km, railway tunnels <3km), excavation or tunneling from both ends is typically employed. For long or extra-long tunnels (highway tunnels ≥1km, railway tunnels ≥3km), new excavation faces are created using pilot tunnels, vertical shafts, or inclined shafts. Since both highway and railway tunnels have a certain longitudinal slope, the main tunnel often involves reverse slope construction during the process, and inclined shaft construction also frequently involves reverse slope construction and drainage. For reverse slope construction in mountain tunnels, drainage becomes a significant challenge. When fissure water exists in the rock mass through which a mountain tunnel passes, the new free face (water head height of 0) created during tunnel construction will form new water collection channels within the mountain. Fissure water at the tunnel face and in the surrounding rock will converge at the tunnel face under reverse slope conditions, leading to softening of the surrounding rock and deterioration of its mechanical parameters (especially for surrounding rocks prone to softening when exposed to water, such as phyllite, mudstone, shale, and loess), endangering the stability of the tunnel face and the overall tunnel. When the tunnel crosses a water-rich fault fracture zone, karst cave, or underground river, mudslides, water inrushes, and gushing water under reverse slope conditions can cause even greater engineering disasters. Improper handling could potentially lead to tunnel collapses, roof falls, and other catastrophic events. Currently, drainage during reverse slope tunnel construction generally relies on mechanical pumping. (1) Drainage methods can be selected according to distance, slope, water volume and equipment, such as drainage ditches or pipelines, to discharge water out of the tunnel in sections or all at once; (2) Excavate reverse slope drainage ditches in sections according to the slope of the line, and excavate a sump at the end of each downhill section so that the water flows into the sump. Then use a water pump to pump the water to the next section of the ditch and into the next sump. In this way, advance section by section to discharge water out of the tunnel. The slope of the reverse slope ditch should not be less than 0.5%. (3) When the tunnel is short, a sump can be excavated near the excavation face and a water pump can be installed to send the water out of the tunnel in one go. (4) The cross-section of the ditch and the capacity of the sump should be determined according to the actual drainage volume. (5) The power of the pump should be more than 20% greater than the power required for drainage, and a backup pump should be available. (6) Prepare for emergency drainage in case of power failure.

[0003] To address the technical problem of water accumulation in tunnels during reverse slope construction, which can easily lead to softening of the rock face and, under special circumstances, water inrush, mudslides, and water surges, thus causing engineering disasters, patent application CN2012101123122 discloses a drainage device and method for long-distance reverse slope tunnels. The drainage device includes a diversion channel, a sedimentation chamber, and a pumping station chamber. The sedimentation chamber and pumping station chamber are located at the water inflow and outflow ends, respectively, with their floor slabs horizontally lower than the tunnel floor. The diversion channel is located on the tunnel floor, with its side connected to the inner edges of the sedimentation chamber and pumping station chamber. A drainage pipe is connected to the outer end of the diversion channel. A water pump is installed in the pumping station chamber. This patent avoids pipe blockage caused by debris accumulation by using the diversion channel, sedimentation chamber, and pumping station chamber, effectively solving the problem of backflow in long-distance reverse slope drainage and improving tunnel construction efficiency. However, this patent document has technical problems such as using a continuous mechanical drainage method, resulting in low drainage efficiency and high power consumption. Summary of the Invention

[0004] To address the technical problems of existing tunnel reverse slope drainage, which mainly adopts continuous mechanical drainage, resulting in low drainage efficiency and high power consumption, this invention proposes a tunnel reverse slope negative pressure siphon drainage method and device.

[0005] This invention utilizes the principle of negative pressure siphon to adsorb water in the sump pit of a tunnel. Under the action of negative pressure adsorption force, the water in the sump pit can be completely adsorbed, which improves drainage efficiency, reduces the power consumption of drainage equipment, and also improves construction progress and construction quality. It has the characteristics and advantages of energy saving and environmental protection.

[0006] The technical solution of the present invention is as follows:

[0007] A tunnel reverse slope negative pressure siphon drainage method includes the following steps:

[0008] S1: Connect the water collection pit inside the tunnel body to the negative pressure chamber inside the adsorption water tank;

[0009] S2: Using the principle of negative pressure siphon, water in the water collection pit is adsorbed into the negative pressure chamber. The water adsorbed in the negative pressure chamber is discharged into the upper water collection chamber. When the water level h in the upper water collection chamber reaches the critical water level h0, the gravity of the water in the upper water collection chamber overcomes the supporting force of the elastic diaphragm valve and opens the elastic diaphragm valve. At this time, the upper water collection chamber is connected to the lower water collection chamber, and the water in the upper water collection chamber is discharged into the lower water collection chamber.

[0010] Further specifying, step S2 also includes: when the water level h in the upper water collection chamber is less than the critical water level h0, the weight of the water in the upper water collection chamber is less than the supporting force of the elastic diaphragm valve, and the elastic diaphragm valve is closed.

[0011] Furthermore, the tunnel reverse slope negative pressure siphon drainage method also includes step S3: discharging water through the lower water collection chamber.

[0012] Further specifying, the pressure calculation formula within the negative pressure chamber is:

[0013]

[0014]

[0015] In the formula, p1 refers to the real-time air pressure in the negative pressure chamber, in MPa; V0 refers to the volume of the upper water collection chamber, in m³. 3 Q1 refers to the vacuum pump's pumping speed, in meters per second (m). 3 / s; t refers to the time it takes for water to begin entering the upper collection chamber from the drain pipe, in seconds; Q2 refers to the drainage rate of the drain pipe, in meters. 3 / s; p0 refers to the standard atmospheric pressure, unit: MPa; v2 refers to the water flow velocity in the drain pipe, unit: m / s; A refers to the radial cross-sectional area of ​​the drain pipe, unit: m². 2 g refers to the acceleration due to gravity, which is taken as g = 9.8 m / s². 2 H t H1 refers to the depth of the water in the sump, in meters (m); H2 refers to the height of the bottom of the sump, in meters (m); H3 refers to the height of the liquid level in the upper sump chamber, in meters (m); γ refers to the specific gravity of water, in N / m³. 3 ζ refers to the local resistance coefficient of the drainage pipe, which is dimensionless; λ refers to the friction coefficient of the drainage pipe, which is dimensionless; L refers to the length of the drainage pipe, in meters; d refers to the inner diameter of the drainage pipe, in meters.

[0016] Furthermore, the formula for calculating the water level h in the upper water collection chamber is:

[0017]

[0018] In the formula, Q2 refers to the drainage rate of the drain pipe, in meters per second (m). 3 / s; t refers to the time it takes for water to begin entering the upper collection chamber from the drain pipe, in seconds; g refers to the acceleration due to gravity, taken as g = 9.8 m / s². 2 A refers to the radial cross-sectional area of ​​the drainage pipe, in meters (m²). 2 H t H1 refers to the depth of the water in the sump, in meters (m); H2 refers to the height of the bottom of the sump, in meters (m); H3 refers to the height of the liquid level in the upper sump chamber, in meters (m); γ refers to the specific gravity of water, in N / m³. 3ζ refers to the local resistance coefficient of the drain pipe, dimensionless; λ refers to the friction coefficient of the drain pipe, dimensionless; L is the length of the drain pipe, in meters; d is the inner diameter of the drain pipe, in meters; S is the bottom area of ​​the upper water collection chamber, in square meters. 2 .

[0019] A tunnel reverse slope negative pressure siphon drainage device includes a drain pipe, an adsorption water tank, and a water collection pit set at the bottom of the reverse slope of the tunnel body. The adsorption water tank is provided with a negative pressure chamber, an upper water collection chamber, and a lower water collection chamber arranged sequentially from top to bottom. The water collection pit is connected to the negative pressure chamber through the drain pipe. The negative pressure chamber is connected to the upper water collection chamber. A partition is provided between the upper water collection chamber and the lower water collection chamber. An elastic partition valve is connected to the partition. The upper water collection chamber is connected to the lower water collection chamber through the elastic partition valve.

[0020] The system utilizes the principle of negative pressure siphon to draw water from the collection pit into the negative pressure chamber. The water drawn into the negative pressure chamber is then discharged into the upper collection chamber. When the water level h in the upper collection chamber reaches the critical water level h0, the weight of the water in the upper collection chamber overcomes the supporting force of the elastic diaphragm valve, opening the valve. At this point, the upper and lower collection chambers are connected, and the water in the upper collection chamber is discharged into the lower collection chamber. When the water level h in the upper collection chamber is less than the critical water level h0, the weight of the water in the upper collection chamber is less than the supporting force of the elastic diaphragm valve, and the valve closes.

[0021] Further specified, the upper water collection chamber is connected to an air extraction device for providing negative pressure; the lower water collection chamber is connected to a water extraction device for draining water.

[0022] Furthermore, the elastic diaphragm valve is provided with a support bar, which is arranged along the water-facing surface of the elastic diaphragm valve.

[0023] Furthermore, the water collection pit is equipped with a filtration device, and the water collection pit is connected to the inlet of the drain pipe through the filtration device.

[0024] Further specifying, the pressure calculation formula within the negative pressure chamber is:

[0025]

[0026]

[0027] In the formula, p1 refers to the real-time air pressure in the negative pressure chamber, in MPa; V0 refers to the volume of the upper water collection chamber, in m³. 3 Q1 refers to the vacuum pump's pumping speed, in meters per second (m). 3 / s; t refers to the time it takes for water to begin entering the upper collection chamber from the drain pipe, in seconds; Q2 refers to the drainage rate of the drain pipe, in meters. 3 / s; p0 refers to the standard atmospheric pressure, unit: MPa; v2 refers to the water flow velocity in the drain pipe, unit: m / s; A refers to the radial cross-sectional area of ​​the drain pipe, unit: m². 2 g refers to the acceleration due to gravity, which is taken as g = 9.8 m / s². 2 H t H1 refers to the depth of the water in the sump, in meters (m); H2 refers to the height of the bottom of the sump, in meters (m); H3 refers to the height of the liquid level in the upper sump chamber, in meters (m); γ refers to the specific gravity of water, in N / m³. 3 ζ refers to the local resistance coefficient of the drainage pipe, which is dimensionless; λ refers to the friction coefficient of the drainage pipe, which is dimensionless; L refers to the length of the drainage pipe, in meters; d refers to the inner diameter of the drainage pipe, in meters.

[0028] The formula for calculating the water level h in the upper water collection chamber is:

[0029]

[0030] In the formula, Q2 refers to the drainage rate of the drain pipe, in meters per second (m). 3 / s; t refers to the time it takes for water to begin entering the upper collection chamber from the drain pipe, in seconds; g refers to the acceleration due to gravity, taken as g = 9.8 m / s². 2 A refers to the radial cross-sectional area of ​​the drainage pipe, in meters (m²). 2 H t H1 refers to the depth of the water in the sump, in meters (m); H2 refers to the height of the bottom of the sump, in meters (m); H3 refers to the height of the liquid level in the upper sump chamber, in meters (m); γ refers to the specific gravity of water, in N / m³. 3 ζ refers to the local resistance coefficient of the drain pipe, dimensionless; λ refers to the friction coefficient of the drain pipe, dimensionless; L is the length of the drain pipe, in meters; d is the inner diameter of the drain pipe, in meters; S is the bottom area of ​​the upper water collection chamber, in square meters. 2 .

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] 1. The present invention relates to a tunnel reverse slope negative pressure siphon drainage method, which connects a water collection pit inside the tunnel body with a negative pressure chamber inside an adsorption box. Water in the water collection pit is adsorbed into the upper water collection chamber via the negative pressure siphon principle. An elastic diaphragm valve is installed between the upper and lower water collection chambers. When the water level h in the upper water collection chamber reaches the critical water level h0, the elastic diaphragm valve opens; when the water level h in the upper water collection chamber is less than the critical water level h0, the elastic diaphragm valve closes. By controlling the water level in the upper water collection chamber using the elastic diaphragm valve, the water level in the upper water collection chamber is kept in dynamic equilibrium, ensuring a constant negative pressure in the negative pressure chamber. This allows for the continuous adsorption of water from the water collection pit into the negative pressure chamber. Under the constant negative pressure adsorption effect of the negative pressure chamber, the water in the water collection pit can be completely adsorbed, improving drainage efficiency, reducing the power consumption of drainage equipment, and also improving construction progress and quality.

[0033] 2. Water is discharged through the lower water collection chamber to prevent water from accumulating there and affecting the pressure. During the water adsorption process, the pressure in the lower water collection chamber must always be maintained at standard atmospheric pressure.

[0034] 3. This invention establishes a calculation model for the water level h in the upper water collection chamber and the pressure in the negative pressure chamber, and limits the pressure in the negative pressure chamber and the water level in the upper water collection chamber to ensure that the pressure in the negative pressure chamber is basically constant, thereby improving the adsorption efficiency of the negative pressure chamber.

[0035] 4. The tunnel reverse slope negative pressure siphon drainage device of the present invention has a water collection pit set at the bottom of the reverse slope of the tunnel body. The water collection pit is connected to the negative pressure chamber of the adsorption water tank through a drainage pipe. The negative pressure chamber uses the principle of negative pressure siphon to adsorb water in the water collection pit in the tunnel to the upper water collection chamber. An elastic diaphragm valve is set between the upper and lower water collection chambers. When the water level h in the upper water collection chamber reaches the critical water level h0, the elastic diaphragm valve opens; when the water level h in the upper water collection chamber is less than the critical water level h0, the elastic diaphragm valve closes. The elastic diaphragm valve controls the water level in the upper water collection chamber, so that the water level in the upper water collection chamber is always in dynamic equilibrium, ensuring that the negative pressure in the negative pressure chamber is constant, and water in the water collection pit can be continuously adsorbed into the negative pressure chamber. Under the constant negative pressure adsorption of the negative pressure chamber, the water in the water collection pit can be completely adsorbed, improving drainage efficiency, and also improving construction progress and construction quality.

[0036] 5. An air extraction device is connected to the upper water collection chamber to provide negative pressure. The air extraction device adsorbs the negative pressure chamber and provides a constant negative pressure condition for the negative pressure chamber. A water pumping device is connected to the lower water collection chamber to provide sufficient flow force to the outlet of the lower water collection chamber to ensure that the water in the lower water collection chamber is discharged in a timely manner.

[0037] 6. A support bar is provided on the elastic diaphragm valve to support the valve and improve its rigidity. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the process of the tunnel reverse slope negative pressure siphon drainage method of the present invention;

[0039] Figure 2 This is a schematic diagram of the tunnel reverse slope negative pressure siphon drainage device of the present invention;

[0040] Figure 3 This is a schematic diagram of the structure of a resilient diaphragm valve;

[0041] Among them, 1-tunnel body, 101-arch lining layer, 102-bottom of tunnel sidewall, 2-sump pit, 3-filtration device, 4-drainage pipe, 5-tunnel entrance, 6-adsorption water tank, 601-lower water collection chamber, 602-upper water collection chamber, 603-negative pressure chamber, 604-inlet, 605-outlet, 7-vacuum pump, 8-partition plate, 9-elastic partition valve, 901-support bar, 10-water pump, 11-one-way valve. Detailed Implementation

[0042] The technical solution of the present invention will be further explained and described below with reference to the accompanying drawings and embodiments, but the present invention is not limited to the embodiments described below.

[0043] Example 1

[0044] See Figure 1 A tunnel reverse slope negative pressure siphon drainage method includes the following steps:

[0045] S1: Connect the water collection pit 2 inside the tunnel body 1 with the negative pressure chamber 603 inside the adsorption water tank 6; preferably, in this embodiment, a drain pipe 4 is provided between the water collection pit 2 and the negative pressure chamber 603, and the drain pipe 4 acts as a siphon to connect the water collection pit 2 and the negative pressure chamber 603.

[0046] S2: Using the principle of negative pressure siphon, the water in the water collection pit 2 is adsorbed into the negative pressure chamber 603. The water adsorbed in the negative pressure chamber 603 is discharged into the upper water collection chamber 602. When the water level h in the upper water collection chamber 602 reaches the critical water level h0, the gravity of the water in the upper water collection chamber 602 overcomes the supporting force of the elastic diaphragm valve 9 and opens the elastic diaphragm valve 9. At this time, the upper water collection chamber 602 is connected to the lower water collection chamber 601, and the water in the upper water collection chamber 602 is discharged into the lower water collection chamber 601.

[0047] Step S2 further includes: when the water level h in the upper water collection chamber 602 is less than the critical water level h0, the weight of the water in the upper water collection chamber 602 is less than the supporting force of the elastic diaphragm valve 9, and the elastic diaphragm valve 9 is closed.

[0048] In this embodiment, a negative pressure chamber 603, an upper water collection chamber 602, and a lower water collection chamber 601 are arranged sequentially from top to bottom inside the adsorption water tank 6. The water collection pit 2 is connected to the negative pressure chamber 603 through a drain pipe 4. The negative pressure chamber 603 is connected to the upper water collection chamber 602. A partition 8 is provided between the upper water collection chamber 602 and the lower water collection chamber 601. An elastic partition valve 9 is connected to the partition 8. The upper water collection chamber 602 is connected to the lower water collection chamber 601 through the elastic partition valve 9.

[0049] Example 2

[0050] This embodiment provides a tunnel reverse slope negative pressure siphon drainage method, which further includes step S3: discharging water through the lower water collection chamber 601.

[0051] The pressure calculation formula within the negative pressure chamber 603 is as follows:

[0052]

[0053]

[0054] In the formula, p1 refers to the real-time air pressure inside the negative pressure chamber 603, in MPa; V0 refers to the volume of the upper water collection chamber 602, in m³. 3 Q1 refers to the pumping speed of vacuum pump 7, in meters per second (m). 3 / s; t refers to the time elapsed since water began to enter the upper water collection chamber 602 from the drain pipe 4, in seconds; Q2 refers to the drainage rate of the drain pipe 4, in meters. 3 / s; p0 refers to the standard atmospheric pressure value, unit: MPa; v2 refers to the water flow velocity in drain pipe 4, unit: m / s; A refers to the radial cross-sectional area of ​​drain pipe 4, unit: m². 2 g refers to the acceleration due to gravity, which is taken as g = 9.8 m / s². 2 H t H1 refers to the depth of the water in sump 2, in meters; H2 refers to the height of the bottom of sump 2, in meters; H2 refers to the liquid level in the upper sump chamber 602, in meters; γ refers to the specific gravity of water, in N / m³. 3 ζ refers to the local resistance coefficient of drain pipe 4, which is dimensionless; λ refers to the friction resistance coefficient of drain pipe 4, which is dimensionless; L refers to the length of drain pipe 4, in meters; d refers to the inner diameter of drain pipe 4, in meters.

[0055] The formula for calculating the water level h in the upper water collection chamber 602 is:

[0056]

[0057] In the formula, Q2 refers to the drainage rate of drain pipe 4, in meters per second (m). 3 / s; t refers to the time elapsed from when water begins to enter the upper water collection chamber (602) from the drain pipe 4, in seconds; g refers to the acceleration due to gravity, taken as g = 9.8 m / s². 2 A refers to the radial cross-sectional area of ​​drain pipe 4, in meters. 2 H t H1 refers to the depth of water in sump 2, in meters; H2 refers to the height of the bottom of sump 2, in meters; H3 refers to the liquid level in the upper sump chamber 602, in meters; γ refers to the specific gravity of water, in N / m³. 3 ζ refers to the local resistance coefficient of drain pipe 4, dimensionless; λ refers to the friction resistance coefficient of drain pipe 4, dimensionless; L is the length of drain pipe 4, in meters; d refers to the inner diameter of drain pipe 4, in meters; S refers to the bottom area of ​​the upper water collection chamber 602, in square meters. 2 .

[0058] The derivation process of the pressure calculation formula in the negative pressure chamber 603 and the water level h calculation formula in the upper water collection chamber 602 is as follows:

[0059] Since the adsorption tank 6 is rigid, the vacuum pump 7 will not reduce the gas volume in the upper water collection chamber 602; it will only reduce the amount of gas molecules. According to the ideal gas law:

[0060] p0V0=n0RT

[0061] p1V1=n1RT

[0062] Therefore

[0063]

[0064] The gas molecular weight in the upper water collection chamber 602

[0065]

[0066] The gas volume in the upper water collection chamber 602 is related to the water inlet rate, i.e.

[0067] V1=V0-∫Q2dt

[0068] The flow rate of drain pipe 4 mainly depends on the effective head of drain pipe 4, which involves the following formula:

[0069] Q2=v2A

[0070]

[0071]

[0072] This leads to the conclusion that

[0073]

[0074]

[0075] In the formula, p1 refers to the real-time air pressure inside the negative pressure chamber 603, in MPa; V0 refers to the volume of the upper water collection chamber 602, in m³. 3 Q1 refers to the pumping speed of vacuum pump 7, in meters per second (m). 3 / s; t refers to the time elapsed since water began to enter the upper water collection chamber 602 from the drain pipe 4, in seconds; Q2 refers to the drainage rate of the drain pipe 4, in meters. 3 / s; p0 refers to the standard atmospheric pressure value, unit: MPa; v2 refers to the water flow velocity in drain pipe 4, unit: m / s; A refers to the radial cross-sectional area of ​​drain pipe 4, unit: m². 2 g refers to the acceleration due to gravity, which is taken as g = 9.8 m / s². 2 H t H1 refers to the depth of water in sump 2, in meters; H2 refers to the height of the bottom of sump 2 (the height of the bottom of sump 2 is based on any reference surface and is consistent with the reference surface of H2), in meters; H2 refers to the liquid level in the upper sump 602, in meters; γ refers to the specific gravity of water, in N / m³. 3 ζ refers to the local resistance coefficient of drain pipe 4, dimensionless; λ refers to the friction coefficient of drain pipe 4, dimensionless; L refers to the length of drain pipe 4, in meters; d refers to the inner diameter of drain pipe 4, in meters; n0 refers to the amount of gas molecules in the upper water collection chamber 602 in the initial state, in mol; R refers to the molar gas constant, in J / (mol·K); T refers to the temperature of the gas in the upper water collection chamber 602, in K; V1 refers to the volume of the gas in the upper water collection chamber 602, in cubic meters. 3 n1 refers to the amount of gas molecules in the upper water collection chamber 602, in mol; H refers to the total hydraulic gradient, in m.

[0076] The formula for calculating the water level h in the upper water collection chamber 602 is:

[0077] Given that the water level depends on the water volume, and the water volume depends on the inflow rate, and since the inflow rate is not constant, the water volume can be calculated by integrating the inflow rate, i.e.:

[0078] Sh=∫Q2dt

[0079] Where S refers to the bottom area of ​​the upper water collection chamber 602, which is a known quantity. The calculation equation for Q2 has been obtained, so it can be derived that:

[0080] The formula for calculating the water level h in the upper water collection chamber 602 is:

[0081]

[0082] In the formula, Q2 refers to the drainage rate of drain pipe 4, in meters per second (m). 3 / s; t refers to the time it takes for water to begin entering the upper water collection chamber 602 from the drain pipe 4, in seconds; g refers to the acceleration due to gravity, taken as g = 9.8 m / s². 2 A refers to the radial cross-sectional area of ​​drain pipe 4, in meters. 2 H t H1 refers to the depth of water in sump 2, in meters; H2 refers to the height of the bottom of sump 2 (the height of the bottom of sump 2 is based on any reference surface and is consistent with the reference surface of H2), in meters; H2 refers to the liquid level in the upper sump 602, in meters; γ refers to the specific gravity of water, in N / m³. 3 ζ refers to the local resistance coefficient of drain pipe 4, dimensionless; λ refers to the friction resistance coefficient of drain pipe 4, dimensionless; L is the length of drain pipe 4, in meters; d refers to the inner diameter of drain pipe 4, in meters; S refers to the bottom area of ​​the upper water collection chamber 602, in square meters. 2 .

[0083] Example 3

[0084] See Figure 2 This embodiment discloses a tunnel reverse slope negative pressure siphon drainage device, which is based on the tunnel reverse slope negative pressure siphon drainage method of Embodiment 1. It includes a drain pipe 4, an adsorption water tank 6, and a water collection pit 2 set at the bottom of the reverse slope of the tunnel body 1. The adsorption water tank 6 is provided with a negative pressure chamber 603, an upper water collection chamber 602, and a lower water collection chamber 601 arranged sequentially from top to bottom. The water collection pit 2 is connected to the negative pressure chamber 603 through the drain pipe 4. The negative pressure chamber 603 is connected to the upper water collection chamber 602. A partition 8 is provided between the upper water collection chamber 602 and the lower water collection chamber 601. An elastic partition valve 9 is connected to the partition 8. The upper water collection chamber 602 is connected to the lower water collection chamber 601 through the elastic partition valve 9. Specifically, the drain pipe 4 acts as a siphon pipe, with its inlet 604 connected to the sump 2 and its outlet connected to the inlet on the negative pressure chamber 603. The negative pressure chamber 603 and the upper sump 602 are connected. Water entering the negative pressure chamber 603 will flow into the upper sump 602. When the water level in the upper sump 602 reaches the critical water level h0, the elastic diaphragm valve 9 opens, draining the water in the upper sump 602 into the lower sump 601. The water in the lower sump 601 is discharged through the outlet 605 provided on it.

[0085] Preferably, the elastic diaphragm valve 9 in this embodiment is made of rubber or soft steel plate; more preferably, the elastic diaphragm valve 9 in this embodiment is made of rubber.

[0086] The water in the collection pit 2 is drawn into the negative pressure chamber 603 by the negative pressure siphon principle. The water drawn into the negative pressure chamber 603 is discharged into the upper collection chamber 602. When the water level h in the upper collection chamber 602 reaches the critical water level h0, the gravity of the water in the upper collection chamber 602 overcomes the supporting force of the elastic diaphragm valve 9 and opens the elastic diaphragm valve 9. At this time, the upper collection chamber 602 is connected to the lower collection chamber 601, and the water in the upper collection chamber 602 is discharged into the lower collection chamber 601. When the water level h in the upper collection chamber 602 is less than the critical water level h0, the gravity of the water in the upper collection chamber 602 is less than the supporting force of the elastic diaphragm valve 9, and the elastic diaphragm valve 9 closes.

[0087] Preferably, in this embodiment, the tunnel body 1 is composed of an arch lining layer 101 and tunnel sidewalls arranged on opposite sides of the arch lining layer 101 along the length of the tunnel body 1. The drainage pipe 4 is located at the bottom 102 of the tunnel sidewall. Specifically, a drainage ditch is provided at the bottom 102 of the tunnel sidewall. The drainage ditch extends along the reverse slope of the tunnel body 1 to the location of the sump 2 and communicates with it. The drainage ditch drains water from the tunnel body 1 to the sump 2 at the bottom of the reverse slope of the tunnel body 1. The drainage pipe 4 is arranged parallel to the drainage ditch. Preferably, to save space, the drainage pipe 4 is located inside the drainage ditch. The location of the sump 2 and the location of the tunnel entrance 5 are respectively on opposite sides of the tunnel body 1, that is, the sump 2 is located on the reverse slope of the tunnel body 1.

[0088] Preferably, in this embodiment, a one-way air valve 11 is provided on the side wall of the lower water collection chamber 601. The air pressure of the lower water collection chamber 601 is adjusted by the one-way air valve 11 to prevent the elastic diaphragm valve from failing to operate due to excessive air pressure in the lower water collection chamber 601.

[0089] Example 4

[0090] This embodiment describes a tunnel reverse slope negative pressure siphon drainage device, wherein the upper water collection chamber 602 is connected to an air extraction device for providing negative pressure; the lower water collection chamber 601 is connected to a water pumping device for drainage. The water in the lower water collection chamber 601 is discharged to a sedimentation tank or sewage treatment plant, and after being treated to meet the standards, it is discharged into a natural ditch.

[0091] Specifically, in this embodiment, the air extraction device is a vacuum pump 7 or other device capable of vacuuming; the water extraction device is a water pump 10 or other device capable of increasing water pressure.

[0092] See Figure 3 In this embodiment, the elastic diaphragm valve 9 is provided with a support bar 901, which is arranged along the water-facing surface of the elastic diaphragm valve 9.

[0093] Specifically, the support bar 901 is made of steel wire or steel plate. Preferably, the support bar 901 is arranged in a staggered grid pattern on the water-facing surface of the elastic diaphragm valve 9.

[0094] In this embodiment, a filter device 3 is installed in the water collection pit 2, and the water collection pit 2 is connected to the water inlet 604 of the drain pipe 4 through the filter device 3. Specifically, the filter device 3 is a filter screen.

[0095] The derivation process of the pressure calculation formula in the negative pressure chamber 603 and the water level h calculation formula in the upper water collection chamber 602 is as follows:

[0096] Since the adsorption tank 6 is rigid, the vacuum pump 7 will not reduce the gas volume in the upper water collection chamber 602; it will only reduce the amount of gas molecules. According to the ideal gas law:

[0097] p0V0=n0RT

[0098] p1V1=n1RT

[0099] Therefore

[0100]

[0101] The gas molecular weight in the upper water collection chamber 602

[0102]

[0103] The gas volume in the upper water collection chamber 602 is related to the water inlet rate, i.e.

[0104] V1=V0-∫Q2dt

[0105] The flow rate of drain pipe 4 mainly depends on the effective head of drain pipe 4, which involves the following formula:

[0106] Q2=v2A

[0107]

[0108]

[0109] This leads to the conclusion that

[0110]

[0111]

[0112] In the formula, p1 refers to the real-time air pressure inside the negative pressure chamber 603, in MPa; V0 refers to the volume of the upper water collection chamber 602, in m³. 3 Q1 refers to the pumping speed of vacuum pump 7, in meters per second (m). 3 / s; t refers to the time elapsed since water began to enter the upper water collection chamber 602 from the drain pipe 4, in seconds; Q2 refers to the drainage rate of the drain pipe 4, in meters. 3 / s; p0 refers to the standard atmospheric pressure value, unit: MPa; v2 refers to the water flow velocity in drain pipe 4, unit: m / s; A refers to the radial cross-sectional area of ​​drain pipe 4, unit: m². 2 g refers to the acceleration due to gravity, which is taken as g = 9.8 m / s². 2 H t H1 refers to the depth of water in sump 2, in meters; H2 refers to the height of the bottom of sump 2 (the height of the bottom of sump 2 is based on any reference surface and is consistent with the reference surface of H2), in meters; H2 refers to the liquid level in the upper sump 602, in meters; γ refers to the specific gravity of water, in N / m³. 3 ζ refers to the local resistance coefficient of drain pipe 4, dimensionless; λ refers to the friction coefficient of drain pipe 4, dimensionless; L refers to the length of drain pipe 4, in meters; d refers to the inner diameter of drain pipe 4, in meters; n0 refers to the amount of gas molecules in the upper water collection chamber 602 in the initial state, in mol; R refers to the molar gas constant, in J / (mol·K); T refers to the temperature of the gas in the upper water collection chamber 602, in K; V1 refers to the volume of the gas in the upper water collection chamber 602, in cubic meters. 3 n1 refers to the amount of gas molecules in the upper water collection chamber 602, in mol; H refers to the total hydraulic gradient, in m.

[0113] The formula for calculating the water level h in the upper water collection chamber 602 is:

[0114] Given that the water level depends on the water volume, and the water volume depends on the inflow rate, and since the inflow rate is not constant, the water volume can be calculated by integrating the inflow rate, i.e.:

[0115] Sh=∫Q2dt

[0116] Where S refers to the bottom area of ​​the upper water collection chamber 602, which is a known quantity. The calculation equation for Q2 has been obtained, so it can be derived that:

[0117] The formula for calculating the water level h in the upper water collection chamber 602 is:

[0118]

[0119] In the formula, Q2 refers to the drainage rate of drain pipe 4, in meters per second (m). 3 / s; t refers to the time it takes for water to begin entering the upper water collection chamber 602 from the drain pipe 4, in seconds; g refers to the acceleration due to gravity, taken as g = 9.8 m / s². 2 A refers to the radial cross-sectional area of ​​drain pipe 4, in meters.2 H t H1 refers to the depth of water in sump 2, in meters; H2 refers to the height of the bottom of sump 2 (the height of the bottom of sump 2 is based on any reference surface and is consistent with the reference surface of H2), in meters; H2 refers to the liquid level in the upper sump 602, in meters; γ refers to the specific gravity of water, in N / m³. 3 ζ refers to the local resistance coefficient of drain pipe 4, dimensionless; λ refers to the friction resistance coefficient of drain pipe 4, dimensionless; L is the length of drain pipe 4, in meters; d refers to the inner diameter of drain pipe 4, in meters; S refers to the bottom area of ​​the upper water collection chamber 602, in square meters. 2 .

[0120] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A tunnel reverse slope negative pressure siphon drainage method, characterized in that, Includes the following steps: S1: Connect the water collection pit (2) inside the tunnel body (1) to the negative pressure chamber (603) inside the adsorption water tank (6); S2: Using the principle of negative pressure siphon, the water in the water collection pit (2) is adsorbed into the negative pressure chamber (603). The water adsorbed in the negative pressure chamber (603) is discharged into the upper water collection chamber (602). When the water level h in the upper water collection chamber (602) reaches the critical water level h0, the gravity of the water in the upper water collection chamber (602) overcomes the supporting force of the elastic diaphragm valve (9) and opens the elastic diaphragm valve (9). At this time, the upper water collection chamber (602) is connected to the lower water collection chamber (601), and the water in the upper water collection chamber (602) is discharged into the lower water collection chamber (601). The pressure calculation formula inside the negative pressure chamber (603) is as follows: In the formula, V0 refers to the real-time air pressure inside the negative pressure chamber (603), in MPa; V0 refers to the volume of the upper water collection chamber (602), in m³. 3 Q1 refers to the pumping speed of the vacuum pump (7), in meters. 3 / s; t refers to the time it takes for water to start flowing from the drain pipe (4) into the upper water collection chamber (602), in seconds; Q2 refers to the drainage rate of the drain pipe (4), in meters. 3 / s; p0 refers to standard atmospheric pressure, unit: MPa; A refers to the water flow velocity in the drain pipe (4), in m / s; A refers to the radial cross-sectional area of ​​the drain pipe (4), in m². 2 ; This refers to gravitational acceleration, taking... H t This refers to the depth of the water in the sump (2), in meters. H1 refers to the height of the bottom of the sump (2), in meters; H2 refers to the liquid level in the upper sump (602), in meters; γ refers to the specific gravity of water, in N / m³. 3 ;ζ refers to the local resistance coefficient of the drainage pipe (4), which is dimensionless; λ refers to the friction resistance coefficient of the drainage pipe (4), which is dimensionless; d refers to the length of the drain pipe (4), in meters; d refers to the inner diameter of the drain pipe (4), in meters. The formula for calculating the water level h in the upper water collection chamber (602) is as follows: In the formula, Q2 refers to the drainage rate of the drain pipe (4), in meters. 3 / s; t refers to the time it takes for water to start flowing from the drain pipe (4) into the upper water collection chamber (602), in seconds; This refers to gravitational acceleration, taking... ; A refers to the radial cross-sectional area of ​​the drain pipe (4), in meters. 2 H t This refers to the depth of the water in the sump (2), in meters. H1 refers to the height of the bottom of the water collection pit (2), in meters; H2 refers to the liquid level in the upper water collection chamber (602), in meters; γ refers to the specific gravity of water, in N / m³. 3 ;ζ refers to the local resistance coefficient of the drainage pipe (4), which is dimensionless; λ refers to the friction resistance coefficient of the drainage pipe (4), which is dimensionless; d is the length of the drain pipe (4), in meters; d refers to the inner diameter of the drain pipe (4), in meters. This refers to the bottom surface area of ​​the upper water collection chamber (602), in m². 2 .

2. The tunnel reverse slope negative pressure siphon drainage method as described in claim 1, characterized in that, Step S2 further includes: when the water level h in the upper water collection chamber (602) is less than the critical water level h0, the weight of the water in the upper water collection chamber (602) is less than the supporting force of the elastic diaphragm valve (9), and the elastic diaphragm valve (9) is closed.

3. The tunnel reverse slope negative pressure siphon drainage method as described in claim 1 or 2, characterized in that, The tunnel reverse slope negative pressure siphon drainage method further includes step S3: draining water through the lower water collection chamber (601).

4. A tunnel reverse slope negative pressure siphon drainage device, characterized in that, The system includes a drain pipe (4), an adsorption tank (6), and a water collection pit (2) located at the bottom of the reverse slope of the tunnel body (1). The adsorption tank (6) is provided with a negative pressure chamber (603), an upper water collection chamber (602), and a lower water collection chamber (601) arranged sequentially from top to bottom. The water collection pit (2) is connected to the negative pressure chamber (603) through the drain pipe (4). The negative pressure chamber (603) is connected to the upper water collection chamber (602). A partition (8) is provided between the upper water collection chamber (602) and the lower water collection chamber (601). An elastic partition valve (9) is connected to the partition (8). The upper water collection chamber (602) is connected to the lower water collection chamber (601) through the elastic partition valve (9). Using the principle of negative pressure siphon, water in the water collection pit (2) is adsorbed into the negative pressure chamber (603). The water adsorbed in the negative pressure chamber (603) is discharged into the upper water collection chamber (602). When the water level h in the upper water collection chamber (602) reaches the critical water level h0, the gravity of the water in the upper water collection chamber (602) overcomes the supporting force of the elastic diaphragm valve (9) and opens the elastic diaphragm valve (9). At this time, the upper water collection chamber (602) is connected to the lower water collection chamber (601), and the water in the upper water collection chamber (602) is discharged into the lower water collection chamber (601). When the water level h in the upper water collection chamber (602) is less than the critical water level h0, the gravity of the water in the upper water collection chamber (602) is less than the supporting force of the elastic diaphragm valve (9), and the elastic diaphragm valve (9) closes. The pressure calculation formula inside the negative pressure chamber (603) is as follows: In the formula, V0 refers to the real-time air pressure inside the negative pressure chamber (603), in MPa; V0 refers to the volume of the upper water collection chamber (602), in m³. 3 Q1 refers to the pumping speed of the vacuum pump (7), in meters. 3 / s; t refers to the time it takes for water to start flowing from the drain pipe (4) into the upper water collection chamber (602), in seconds; Q2 refers to the drainage rate of the drain pipe (4), in meters. 3 / s; p0 refers to standard atmospheric pressure, unit: MPa; A refers to the water flow velocity in the drain pipe (4), in m / s; A refers to the radial cross-sectional area of ​​the drain pipe (4), in m². 2 ; This refers to gravitational acceleration, taking... H t This refers to the depth of the water in the sump (2), in meters. H1 refers to the height of the bottom of the sump (2), in meters; H2 refers to the liquid level in the upper sump (602), in meters; γ refers to the specific gravity of water, in N / m³. 3 ;ζ refers to the local resistance coefficient of the drainage pipe (4), which is dimensionless; λ refers to the friction resistance coefficient of the drainage pipe (4), which is dimensionless; d refers to the length of the drain pipe (4), in meters; d refers to the inner diameter of the drain pipe (4), in meters. The formula for calculating the water level h in the upper water collection chamber (602) is as follows: In the formula, Q2 refers to the drainage rate of the drain pipe (4), in meters. 3 / s; t refers to the time it takes for water to start flowing from the drain pipe (4) into the upper water collection chamber (602), in seconds; This refers to gravitational acceleration, taking... ; A refers to the radial cross-sectional area of ​​the drain pipe (4), in meters. 2 H t This refers to the depth of the water in the sump (2), in meters. H1 refers to the height of the bottom of the water collection pit (2), in meters; H2 refers to the liquid level in the upper water collection chamber (602), in meters; γ refers to the specific gravity of water, in N / m³. 3 ;ζ refers to the local resistance coefficient of the drainage pipe (4), which is dimensionless; λ refers to the friction resistance coefficient of the drainage pipe (4), which is dimensionless; d is the length of the drain pipe (4), in meters; d refers to the inner diameter of the drain pipe (4), in meters. This refers to the bottom surface area of ​​the upper water collection chamber (602), in m². 2 .

5. The tunnel reverse slope negative pressure siphon drainage device as described in claim 4, characterized in that, The upper water collection chamber (602) is connected to an air pump for providing negative pressure; the lower water collection chamber (601) is connected to a water pump for draining water.

6. The tunnel reverse slope negative pressure siphon drainage device as described in claim 4, characterized in that, The elastic diaphragm valve (9) is provided with a support bar (901), which is arranged along the water-facing side of the elastic diaphragm valve (9).

7. The tunnel reverse slope negative pressure siphon drainage device as described in claim 6, characterized in that, The water collection pit (2) is equipped with a filter device (3), and the water collection pit (2) is connected to the inlet of the drain pipe (4) through the filter device (3).

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