A method for constructing a water conveyance tunnel intersection and a water collection system

Abstract

This invention relates to the field of water conservancy and hydropower engineering technology, specifically to a construction method and system for the confluence of water at the intersection of a water conveyance tunnel. The construction method includes excavating a main tunnel, excavating a main-branch tunnel intersection on the main tunnel, and establishing a straight central axis for the branch tunnel at the intersection, such that the straight central axis of the branch tunnel is angled to the straight central axis of the main tunnel. The branch tunnel is then excavated according to the established straight central axis, and the straight central axis at the end of the branch tunnel is reconstructed as an arc-shaped central axis, tangent to the straight central axis of the main tunnel. A guide pier of the same arc is placed inside the end of the branch tunnel to guide the water flow from the branch tunnel into the downstream of the main tunnel. This invention reduces the angle between the water flow direction in the branch tunnel and the water flow direction in the main tunnel at the main-branch tunnel intersection, thereby significantly improving the jacking effect of the branch tunnel water flow on the inner wall of the main tunnel and enhancing the stability of the main tunnel's sidewall structure.

Description

Technical Field

[0001] This invention relates to the field of water conservancy and hydropower engineering technology, and in particular to a method for constructing a water conveyance tunnel intersection and a water collection system. Background Technology

[0002] Water conveyance tunnels are an important component of hydropower station projects. They are artificial tunnels carved and lined into mountains, serving both water conveyance and flood discharge functions. Water conveyance tunnels are usually single-bore tunnels. However, with the continuous advancement of technology, more and more water conveyance tunnels are adopting a combination of main and branch tunnels, with the branch tunnel outlet located inside the main tunnel. Water from the branch tunnel flows into the main tunnel through the intersection of the main and branch tunnels.

[0003] However, due to geological limitations, the closer the axis of the branch tunnel is to the axis of the main tunnel at 90°, the more severe the impact of the water flow from the branch tunnel into the main tunnel on the sidewalls of the main tunnel. Furthermore, the surge generated by the water flow from the branch tunnel hitting the sidewalls of the main tunnel will roll to the top of the tunnel, causing the water flow to block the tunnel at the tunnel intersection, which seriously affects the tunnel's water conveyance, flood discharge, and the safe operation of the structures. Summary of the Invention

[0004] The technical problem to be solved by the embodiments of the present invention is to provide a method and system for constructing a water confluence at the intersection of a water conveyance tunnel, so as to solve the problem that water flow is easily blocked at the tunnel intersection in the prior art.

[0005] This invention discloses a method for constructing a water conveyance tunnel intersection confluence, comprising:

[0006] Based on the actual conditions of the project, a main tunnel will be excavated for water conveyance and flood discharge.

[0007] A main-branch tunnel intersection is formed by excavating the first side wall located on one side of the main tunnel, and a straight central axis of the branch tunnel is established from the main-branch tunnel intersection, so that the straight central axis of the branch tunnel and the straight central axis of the main tunnel are arranged at an angle.

[0008] Based on the straight central axis established by the branch tunnel, the branch tunnel is excavated upstream from the intersection of the main branch tunnel;

[0009] Based on the straight central axis established by the branch tunnel, located at the end of the branch tunnel where it connects to the main branch tunnel, the straight central axis at the end of the branch tunnel is reconstructed as an arc-shaped central axis until the arc-shaped central axis at the end of the branch tunnel is tangent to the straight central axis of the main tunnel.

[0010] Based on the reconstructed arc-shaped central axis at the end of the branch tunnel, guide piers of the same arc are installed inside the end of the branch tunnel to guide the water flow in the branch tunnel into the downstream of the main tunnel.

[0011] Optionally, the reconstruction of the straight centerline at the end of the branch tunnel is an arc-shaped centerline, including:

[0012] Determine the width of the excavation for the branch tunnel;

[0013] Based on the determined excavation width of the branch tunnel, the radius of the arc-shaped central axis at the end of the branch tunnel is determined, and the functional expression for the radius of the arc-shaped central axis at the end of the branch tunnel is:

[0014]

[0015] In the formula, R represents the radius of the arc-shaped centerline at the end of the branch tunnel. This indicates the width of the branch tunnel excavation.

[0016] Optionally, the excavation of the branch tunnel upstream from the intersection of the main and branch tunnels includes:

[0017] The branch tunnel is excavated upstream from the intersection of the main branch tunnel and the side wall of the branch tunnel located downstream of the intersection of the main branch tunnel is used as the second side wall.

[0018] At the initial stage of the excavation of the branch tunnel, based on the arc-shaped central axis reconstructed at the end of the branch tunnel, an arc-shaped lining line concentric with the arc-shaped central axis at the end of the branch tunnel is established at the downstream edge of the intersection of the main branch tunnel, so that the arc-shaped lining line is tangent to the first side wall of the main tunnel.

[0019] Based on the established arc-shaped lining line, establish a straight lining line parallel to the central axis of the branch tunnel, so that the straight lining line is tangent to the arc-shaped lining line, and connect the arc-shaped lining line and the straight lining line at the tangent point to establish a side wall lining line.

[0020] The second sidewall is lined along the established sidewall lining line.

[0021] Optionally, the step of arranging guide piers of the same arc degree within the end of the branch tunnel, based on the reconstructed arc-shaped central axis at the end of the branch tunnel, includes:

[0022] Based on the reconstructed arc-shaped central axis at the end of the branch tunnel, the guide piers are respectively set on both sides of the arc-shaped central axis, so that an arc-shaped guide area tangent to the water flow direction in the main tunnel is formed between the two guide piers and between the guide piers and the adjacent sidewall of the branch tunnel.

[0023] Optionally, the method for deploying the diversion piers includes:

[0024] A first arc curve and a second arc curve are established in parallel along the width direction of the branch tunnel, and both the first arc curve and the second arc curve are concentric circles with the arc-shaped central axis at the end of the branch tunnel.

[0025] Construct the guide walls on both sides of the guide pier based on the connected first and second arc curves.

[0026] Optionally, the method for deploying the diversion piers further includes:

[0027] A third arc curve is established upstream of the first arc curve, such that the third arc curve is tangent to both the first and second arc curves, and the third arc curve is connected to both the first and second arc curves at the points of tangency.

[0028] Based on the connected third arc curve, construct the guide wall of the guide pier facing the upstream water flow.

[0029] Optionally, the method for deploying the diversion piers further includes:

[0030] A fourth arc curve is established downstream of the second arc curve, such that the fourth arc curve is tangent to the second arc curve and is tangent to the extension line of the first side wall of the main tunnel, and the fourth arc curve and the second arc curve are connected at the point of tangency;

[0031] Based on the fourth arc-shaped curve after connection, the guide pier is constructed to guide the water flow in the branch tunnel tangentially into the guide wall downstream of the main tunnel.

[0032] Optionally, the method for deploying the diversion piers further includes:

[0033] A straight construction line perpendicular to the main tunnel water flow direction is established downstream of the first arc curve, and the first arc curve and the fourth arc curve are extended downstream to the straight construction line for connection;

[0034] The guide piers are constructed according to the straight construction line after connection, so that the water flow on both sides can be respectively drawn into the intercepting wall downstream of the main tunnel.

[0035] Optionally, the method includes the excavation of the main tunnel and the branch tunnel:

[0036] Based on the actual conditions of the project, the excavation point of the main tunnel is selected in the target area;

[0037] According to the selected main tunnel excavation point, the main tunnel is excavated, and during the excavation process, temporary support is provided for the side walls, bottom slab and arch of the main tunnel;

[0038] After the main tunnel excavation is completed, permanent support and lining are carried out on the side walls, floor slab and arch of the main tunnel;

[0039] According to the confluence requirements, the side wall on one side of the main tunnel is selected as the first side wall, and the intersection of the main and branch tunnels is excavated on the first side wall;

[0040] Based on the straight central axis established by the branch tunnel, the branch tunnel is excavated upstream along the straight central axis, and temporary support is provided for the side walls, bottom slab and arch of the branch tunnel during the excavation process;

[0041] After the excavation of the branch tunnel is completed, the side walls, bottom slab and arch of the branch tunnel are permanently supported and lined.

[0042] The present invention also discloses a confluence system, which adopts the above-mentioned construction method for confluence construction at the intersection of water conveyance tunnels. The confluence system includes a main tunnel, a branch tunnel, and a guide pier. The branch tunnel is connected to the main tunnel, and the central axis of the branch tunnel is set at an angle to the central axis of the main tunnel. The guide pier is an arc-shaped pier set at the intersection of the branch tunnel and the main tunnel, and the guiding direction of the guide pier is tangent to the water flow direction of the main tunnel.

[0043] Compared with the prior art, the beneficial effects of the water conveyance tunnel intersection confluence construction method and confluence system provided in this embodiment of the invention are as follows:

[0044] By establishing a straight central axis for the branch tunnel during excavation, the precise location of the branch tunnel excavation is ensured, deviations are avoided, and the correct relative position between the branch tunnel and the main tunnel is guaranteed. Furthermore, by arranging the straight central axis of the branch tunnel at an angle to the straight central axis of the main tunnel, the angle between the branch tunnel and the main tunnel can be precisely controlled, which is beneficial for controlling the confluence direction of the main tunnel and the branch tunnel and can reduce the impact of water from the branch tunnel on the water pressure inside the main tunnel. Based on this, by establishing an arc-shaped central axis at the end of the branch tunnel tangent to the straight central axis of the main tunnel, and placing guide piers with the same curvature as the arc-shaped central axis, the water flow in the branch tunnel is introduced downstream of the main tunnel in a direction tangential to the water flow in the main tunnel. This reduces the angle between the water flow direction in the branch tunnel and the water flow direction in the main tunnel at the intersection of the main tunnel and the branch tunnel, thereby significantly improving the jacking effect of the water flow in the branch tunnel on the inner sidewall of the main tunnel and enhancing the stability of the main tunnel's sidewall structure. At the same time, the water flowing into the main tunnel from the branch tunnel will not surge up to the top of the side wall and then roll back down, which effectively improves the flow pattern at the intersection of the main and branch tunnels and avoids obstructing the water conveyance and flood discharge of the main tunnel. Attached Figure Description

[0045] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0046] Figure 1 This is a schematic diagram of the main tunnel and branch tunnel confluence structure of the water conveyance tunnel intersection construction method provided in an embodiment of the present invention;

[0047] Figure 2 A schematic diagram showing the distribution of the central axis of the main tunnel and the branch tunnels provided in an embodiment of the present invention;

[0048] Figure 3 This is a schematic diagram of the structure of the guide pier provided in an embodiment of the present invention.

[0049] The labels for the attached figures are as follows:

[0050] 1. Main tunnel; 11. First side wall; 2. Secondary tunnel; 21. Second side wall; 3. Arc-shaped central axis; 4. Guide pier; 41. First arc-shaped curve; 42. Second arc-shaped curve; 43. Third arc-shaped curve; 44. Fourth arc-shaped curve; 45. Straight construction line. Detailed Implementation

[0051] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0052] This invention discloses a method for constructing a water conveyance tunnel intersection confluence, such as... Figure 1 and Figure 2 As shown, it includes:

[0053] Based on the actual conditions of the project, a main tunnel 1 will be excavated for water conveyance and flood discharge.

[0054] The intersection of the main tunnel and the branch tunnel 2 is formed by excavation on the first side wall 11 located on one side of the main tunnel 1, and the straight centerline of the branch tunnel 2 is established at the intersection of the main tunnel and the branch tunnel 2, so that the straight centerline of the branch tunnel 2 and the straight centerline of the main tunnel 1 are arranged at an angle.

[0055] Based on the straight central axis established by branch tunnel 2, branch tunnel 2 is excavated upstream from the intersection of branch tunnel 2.

[0056] Based on the straight central axis established by the branch tunnel 2, located at the end of the intersection where the branch tunnel 2 connects to the main branch tunnel 2, the straight central axis at the end of the branch tunnel 2 is reconstructed as an arc-shaped central axis 3 until the arc-shaped central axis 3 at the end of the branch tunnel 2 is tangent to the straight central axis of the main tunnel 1.

[0057] Based on the reconstructed arc-shaped central axis 3 at the end of branch tunnel 2, a guide pier 4 with the same arc is installed inside the end of branch tunnel 2 to guide the water flow in branch tunnel 2 into the downstream of main tunnel 1.

[0058] Through the implementation of the above-described method for constructing the confluence of water conveyance tunnel intersections, during the excavation of branch tunnel 2, a main tunnel 1 is first excavated for water conveyance and flood discharge. The intersection of the main tunnel and branch tunnel 2 is then excavated on the main tunnel 1, serving as the confluence point for the water flow from branch tunnel 2 into the main tunnel 1. Next, the straight central axis of branch tunnel 2 is established to ensure the precise location of the branch tunnel 2 excavation, avoid deviations, and guarantee the correct relative position of branch tunnel 2 and main tunnel 1. Furthermore, by arranging the straight central axis of branch tunnel 2 at an angle to the straight central axis of main tunnel 1, the angle between branch tunnel 2 and main tunnel 1 can be precisely controlled. This facilitates the control of the confluence direction of main tunnel 1 and branch tunnel 2 and reduces the impact of water flow from branch tunnel 2 on the internal water pressure of main tunnel 1. Based on this, by establishing an arc-shaped central axis 3 at the end of branch tunnel 2 tangent to the straight central axis of main tunnel 1, and installing guide piers 4 with the same curvature as the arc-shaped central axis 3, the water flow in branch tunnel 2 is diverted downstream of main tunnel 1 in a direction tangential to the water flow in main tunnel 1 after the excavation of branch tunnel 2. This reduces the angle between the water flow direction in branch tunnel 2 and the water flow direction in main tunnel 1 at the intersection of branch tunnel 2 and main tunnel 1, significantly improving the impact of the water flow in branch tunnel 2 on the inner sidewall of main tunnel 1 and enhancing the stability of the sidewall structure of main tunnel 1. Simultaneously, the water flow from branch tunnel 2 into main tunnel 1 will not experience the phenomenon of impacting the sidewall, climbing to the top of the sidewall, and then tumbling down, effectively improving the flow pattern at the intersection of branch tunnel 2 and avoiding obstruction of water conveyance and flood discharge in main tunnel 1. Furthermore, due to the significant phenomenon of water flow impacting the sidewall of the main tunnel 1 in traditional branch tunnel 2, and the need to raise the entire sidewall at the intersection of the main and branch tunnels to meet the specifications for sidewall height, the excavation work is extensive and the support is difficult. This embodiment of the invention utilizes the diversion pier 4 to avoid raising the entire sidewall of the main tunnel 1, offering advantages such as convenient construction and cost savings.

[0059] Furthermore, the straight central axis at the end of the reconstructed branch tunnel 2 is an arc-shaped central axis 3, including:

[0060] Determine the width of the excavation for branch tunnel 2;

[0061] Based on the excavation width determined for branch tunnel 2, the radius of the arc-shaped central axis 3 at the end of branch tunnel 2 is determined. The functional expression for the radius of the arc-shaped central axis 3 at the end of branch tunnel 2 is as follows:

[0062]

[0063] In the formula, R represents the radius of the arc-shaped central axis 3 at the end of the branch tunnel 2. This indicates the width of the excavation for branch tunnel 2.

[0064] By implementing the above-described method for constructing the confluence of water conveyance tunnel intersections, the width of the branch tunnel 2 is proportionally set to the radius of the arc-shaped central axis 3 at the end of the branch tunnel 2. This fully considers the water flow rate within the branch tunnel 2, ensuring that the guide pier 4 at the end of the branch tunnel 2 has a guiding arc that matches the water flow rate. This allows the water flow in the branch tunnel 2 to be introduced downstream of the main tunnel 1 in a direction tangential to the water flow in the main tunnel 1, thereby reducing water flow resistance, improving the guiding efficiency of the water flow in the branch tunnel 2, and preventing the formation of eddies and backflows when the water flow in the branch tunnel 2 converges.

[0065] Further, the branch tunnel 2 is excavated upstream from the intersection of the main branch tunnel 2, including:

[0066] The branch tunnel 2 is excavated upstream from the intersection of the main branch tunnel 2, and the side wall of the branch tunnel 2 located downstream of the intersection of the main branch tunnel 2 is used as the second side wall 21.

[0067] At the beginning of the excavation of branch tunnel 2, based on the arc-shaped central axis 3 reconstructed at the end of branch tunnel 2, an arc-shaped lining line concentric with the arc-shaped central axis 3 at the downstream edge of the intersection of main branch tunnel 2 is established, so that the arc-shaped lining line is tangent to the first side wall 11 of main tunnel 1.

[0068] Based on the established arc-shaped lining line, establish a straight lining line parallel to the central axis of branch tunnel 2, so that the straight lining line is tangent to the arc-shaped lining line, and connect the arc-shaped lining line and the straight lining line at the tangent point to establish the side wall lining line.

[0069] Lin the second side wall 21 along the established side wall lining line.

[0070] Through the implementation of the above-described method for constructing the confluence of water conveyance tunnel intersections, it is found that the water flow in the branch tunnel 2 is downstream of the water flow in the main tunnel 1 during the confluence. Since the traditional junction of the main and branch tunnel 2 sidewalls forms sharp corners, these areas are prone to negative pressure due to the scouring and shearing action of the downstream water flow, leading to cavitation and erosion damage to the sidewalls. Therefore, this invention establishes a sidewall lining line composed of an arc-shaped lining line and a straight lining line to line the second sidewall 21. This sidewall of the branch tunnel 2 is located downstream of the intersection of the main and branch tunnels 2, ensuring that the end of the second sidewall 21 is tangentially connected to the first sidewall 11 of the main tunnel 1. This creates an arc-shaped structure at the junction of the main tunnel 1 and the branch tunnel 2 sidewalls, avoiding sharp corners. This makes the water flow in the main tunnel 1 or branch tunnel 2 smoother at the intersection of the main and branch tunnels 2, while also preventing cavitation damage.

[0071] Furthermore, based on the reconstructed arc-shaped central axis 3 at the end of branch tunnel 2, guide piers 4 with the same arc are arranged inside the end of branch tunnel 2, including:

[0072] Based on the reconstructed arc-shaped central axis 3 at the end of branch tunnel 2, guide piers 4 are set on both sides of the arc-shaped central axis 3, so that an arc-shaped guide area tangent to the water flow direction in the main tunnel 1 is formed between the two guide piers 4 and between the guide piers 4 and the side wall of the adjacent branch tunnel 2.

[0073] Furthermore, combined Figure 3 As shown, the layout method includes the diversion pier 4:

[0074] A first arc curve 41 and a second arc curve 42 are established in parallel along the width direction of the branch tunnel 2, and the first arc curve 41 and the second arc curve 42 are both concentric circles with the arc-shaped central axis 3 at the end of the branch tunnel 2.

[0075] Construct the guide walls on both sides of the guide pier 4 based on the first arc curve 41 and the second arc curve 42 after connection.

[0076] Furthermore, the arrangement method of the diversion pier 4 also includes:

[0077] A third arc curve 43 is established upstream of the first arc curve 41, such that the third arc curve 43 is tangent to the first arc curve 41 and the second arc curve 42 respectively, and the third arc curve 43 is connected to the first arc curve 41 and the second arc curve 42 at the tangent point respectively.

[0078] Based on the third arc curve 43 after connection, construct the guide pier 4 to face the upstream water flow.

[0079] Furthermore, the arrangement method of the diversion pier 4 also includes:

[0080] A fourth arc curve 44 is established downstream of the second arc curve 42, so that the fourth arc curve 44 is tangent to the second arc curve 42, and the fourth arc curve 44 is tangent to the extension line of the first side wall 11 of the main tunnel 1, and the fourth arc curve 44 and the second arc curve 42 are connected at the point of tangency.

[0081] Based on the fourth arc curve 44 after connection, a guide pier 4 is built to guide the water flow in the branch tunnel 2 into the guide wall downstream of the main tunnel 1 through tangential flow.

[0082] Furthermore, the arrangement method of the diversion pier 4 also includes:

[0083] A straight construction line 45 perpendicular to the water flow direction of the main tunnel 1 is established downstream of the first arc curve 41, and the first arc curve 41 and the fourth arc curve 44 are extended downstream to the straight construction line 45 for connection.

[0084] Construct guide piers 4 along the straight construction line 45 after connection to allow the water flow on both sides to flow into the downstream intercepting wall of the main tunnel 1.

[0085] Through the implementation of the above-described method for constructing the confluence of water conveyance tunnel intersections, the shape of the guide pier 4 is composed of multiple arc-shaped curves and a straight construction line 45. The guide walls on both sides of the guide pier 4 are constructed using the first arc-shaped curve 41 and the second arc-shaped curve 42, which helps the water flow on both sides of the guide pier 4 to smoothly transition at the end of the branch tunnel 2, reducing water flow resistance and energy loss, and providing a clear flow path for the water flow, preventing scouring and erosion of the branch tunnel 2 walls, and enhancing the structural stability of the branch tunnel 2. The guide wall facing the upstream water flow is constructed using the third arc-shaped curve 43, allowing the water flow from upstream of the branch tunnel 2 to smoothly transition along the guide wall facing the upstream water flow to both sides of the guide pier 4 when it enters the end of the branch tunnel 2, thereby reducing the impact force of the water flow on the guide pier 4. The tangential design reduces eddies and resistance when water flows into the guide pier 4, improving flow efficiency. The guide pier 4, constructed using the fourth arc curve 44, guides the water flow from branch tunnel 2 tangentially into the downstream guide wall of main tunnel 1. This ensures a smooth transition and reduces impact. The tangential design also ensures the water flows along a predetermined path, minimizing erosion of the main tunnel 1's sidewalls. The guide pier 4, constructed using a straight construction line 45, directs the water flow from both sides into the downstream intercepting wall of main tunnel 1, guiding the flow from both sides of the guide pier 4 into the downstream of main tunnel 1. This avoids merging of the water flow from both sides of the guide pier 4 before entering main tunnel 1, significantly reducing the impact of the water flow from branch tunnel 2 on the inner sidewall of main tunnel 1 and improving the stability of the main tunnel 1's sidewall structure. Therefore, the arrangement of the above-mentioned diversion piers 4 can make the angle between the water flow in the branch tunnel 2 and the water flow in the main tunnel 1 smaller, and also ensure that the end of the diversion piers 4 will not interfere with the water flow in the main tunnel 1.

[0086] Furthermore, the excavation methods for the main tunnel 1 and the branch tunnel 2 are as follows:

[0087] Based on the actual conditions of the project, the excavation point of main tunnel 1 was selected in the target area;

[0088] Based on the selected excavation point of the main tunnel 1, the main tunnel 1 was excavated, and temporary support was provided for the side walls, bottom slab and arch of the main tunnel 1 during the excavation process.

[0089] After the excavation of the main tunnel 1 is completed, permanent support and lining will be carried out on the side walls, floor slab and arch of the main tunnel 1.

[0090] According to the confluence requirements, the side wall on one side of the main tunnel 1 is selected as the first side wall 11, and the intersection of the main branch tunnel 2 is excavated on the first side wall 11.

[0091] Based on the straight central axis established by the branch tunnel 2, the branch tunnel 2 is excavated upstream along the straight central axis, and temporary support is provided for the side walls, bottom slab and arch of the branch tunnel 2 during the excavation process.

[0092] After the excavation of branch tunnel 2 is completed, permanent support and lining are carried out on the side walls, bottom slab and arch of branch tunnel 2.

[0093] The present invention also discloses a confluence system, which adopts the above-mentioned construction method for confluence construction at the intersection of water conveyance tunnels. The confluence system includes a main tunnel 1, a branch tunnel 2, and a guide pier 4. The branch tunnel 2 is connected to the main tunnel 1, and the central axis of the branch tunnel 2 is set at an angle to the central axis of the main tunnel 1. The guide pier 4 is an arc-shaped pier set at the intersection of the branch tunnel 2 and the main tunnel 1, and the guiding direction of the guide pier 4 is tangent to the water flow direction of the main tunnel 1.

[0094] By implementing the aforementioned confluence system, and by placing guide piers 4 at the junction of branch tunnel 2 and main tunnel 1, the water flow in branch tunnel 2 is directed downstream of main tunnel 1. This also reduces the angle between the water flow direction in branch tunnel 2 and the sidewall of main tunnel 1, significantly mitigating the impact of the water flow in branch tunnel 2 on the sidewall of main tunnel 1, thus improving the structural stability of the sidewall of main tunnel 1. Simultaneously, the water flow in branch tunnel 2 will no longer experience the phenomenon of impacting the sidewall, rising to the top, and then tumbling down, effectively improving the flow pattern at the intersection of main and branch tunnels 2 and eliminating any obstruction to water conveyance and flood discharge in main tunnel 1.

[0095] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some of the technical features; and all such modifications and substitutions should fall within the protection scope of the appended claims of the present invention.

Claims

1. A method for constructing a water conveyance tunnel intersection confluence, characterized in that, The construction method for the confluence of water conveyance tunnel intersections includes: Based on the actual conditions of the project, a main tunnel will be excavated for water conveyance and flood discharge. A main-branch tunnel intersection is formed by excavating the first side wall located on one side of the main tunnel, and a straight central axis of the branch tunnel is established from the main-branch tunnel intersection, so that the straight central axis of the branch tunnel and the straight central axis of the main tunnel are arranged at an angle. Based on the straight central axis established by the branch tunnel, the branch tunnel is excavated upstream from the intersection of the main branch tunnel; Based on the straight central axis established by the branch tunnel, located at the end of the branch tunnel where it connects to the main branch tunnel, the straight central axis at the end of the branch tunnel is reconstructed as an arc-shaped central axis until the arc-shaped central axis at the end of the branch tunnel is tangent to the straight central axis of the main tunnel. Based on the reconstructed arc-shaped central axis at the end of the branch tunnel, guide piers of the same arc are installed inside the end of the branch tunnel to guide the water flow in the branch tunnel into the downstream of the main tunnel.

2. The construction method for the confluence of water conveyance tunnel intersections according to claim 1, characterized in that, The reconstruction of the straight centerline at the end of the branch tunnel is an arc-shaped centerline, including: Determine the width of the excavation for the branch tunnel; Based on the determined excavation width of the branch tunnel, the radius of the arc-shaped central axis at the end of the branch tunnel is determined, and the functional expression for the radius of the arc-shaped central axis at the end of the branch tunnel is: In the formula, R represents the radius of the arc-shaped centerline at the end of the branch tunnel. This indicates the width of the branch tunnel excavation.

3. The construction method for the confluence of water conveyance tunnel intersections according to claim 1 or 2, characterized in that, The excavation of the branch tunnel upstream from the intersection of the main tunnel and the branch tunnel includes: The branch tunnel is excavated upstream from the intersection of the main branch tunnel and the side wall of the branch tunnel located downstream of the intersection of the main branch tunnel is used as the second side wall. At the initial stage of the excavation of the branch tunnel, based on the arc-shaped central axis reconstructed at the end of the branch tunnel, an arc-shaped lining line concentric with the arc-shaped central axis at the end of the branch tunnel is established at the downstream edge of the intersection of the main branch tunnel, so that the arc-shaped lining line is tangent to the first side wall of the main tunnel. Based on the established arc-shaped lining line, establish a straight lining line parallel to the central axis of the branch tunnel, so that the straight lining line is tangent to the arc-shaped lining line, and connect the arc-shaped lining line and the straight lining line at the tangent point to establish a side wall lining line. The second sidewall is lined along the established sidewall lining line.

4. The construction method for the confluence of water conveyance tunnel intersections according to claim 1, characterized in that, The method of constructing guide piers with the same curvature within the end of the branch tunnel, based on the reconstructed arc-shaped central axis at the end of the branch tunnel, includes: Based on the reconstructed arc-shaped central axis at the end of the branch tunnel, the guide piers are respectively set on both sides of the arc-shaped central axis, so that an arc-shaped guide area tangent to the water flow direction in the main tunnel is formed between the two guide piers and between the guide piers and the adjacent sidewall of the branch tunnel.

5. The construction method for the confluence of water conveyance tunnel intersections according to claim 1, characterized in that, Including the method of arranging the diversion piers: A first arc curve and a second arc curve are established in parallel along the width direction of the branch tunnel, and both the first arc curve and the second arc curve are concentric circles with the arc-shaped central axis at the end of the branch tunnel. Construct the guide walls on both sides of the guide pier based on the connected first and second arc curves.

6. The construction method for the confluence of water conveyance tunnel intersections according to claim 5, characterized in that, The method for deploying the diversion piers also includes: A third arc curve is established upstream of the first arc curve, such that the third arc curve is tangent to both the first and second arc curves, and the third arc curve is connected to both the first and second arc curves at the points of tangency. Based on the connected third arc curve, construct the guide wall of the guide pier facing the upstream water flow.

7. The construction method for the confluence of water conveyance tunnel intersections according to claim 6, characterized in that, The method for deploying the diversion piers also includes: A fourth arc curve is established downstream of the second arc curve, such that the fourth arc curve is tangent to the second arc curve and is tangent to the extension line of the first side wall of the main tunnel, and the fourth arc curve and the second arc curve are connected at the point of tangency; Based on the fourth arc-shaped curve after connection, the guide pier is constructed to guide the water flow in the branch tunnel tangentially into the guide wall downstream of the main tunnel.

8. The construction method for the confluence of water conveyance tunnel intersections according to claim 7, characterized in that, The method for deploying the diversion piers also includes: A straight construction line perpendicular to the main tunnel water flow direction is established downstream of the first arc curve, and the first arc curve and the fourth arc curve are extended downstream to the straight construction line for connection; The guide piers are constructed according to the straight construction line after connection, so that the water flow on both sides can be respectively drawn into the intercepting wall downstream of the main tunnel.

9. The construction method for the confluence of water conveyance tunnel intersections according to claim 1, characterized in that, The excavation methods include those for the main tunnel and the branch tunnel: Based on the actual conditions of the project, the excavation point of the main tunnel is selected in the target area; According to the selected main tunnel excavation point, the main tunnel is excavated, and during the excavation process, temporary support is provided for the side walls, bottom slab and arch of the main tunnel; After the main tunnel excavation is completed, permanent support and lining are carried out on the side walls, floor slab and arch of the main tunnel; According to the confluence requirements, the side wall on one side of the main tunnel is selected as the first side wall, and the intersection of the main and branch tunnels is excavated on the first side wall; Based on the straight central axis established by the branch tunnel, the branch tunnel is excavated upstream along the straight central axis, and temporary support is provided for the side walls, bottom slab and arch of the branch tunnel during the excavation process; After the excavation of the branch tunnel is completed, the side walls, bottom slab and arch of the branch tunnel are permanently supported and lined.

10. A bus system, characterized in that, The water conveyance tunnel intersection confluence construction method according to any one of claims 1-9 is adopted, wherein the confluence system includes a main tunnel, a branch tunnel, and a guide pier. The branch tunnel is connected to the main tunnel, and the central axis of the branch tunnel is set at an angle to the central axis of the main tunnel. The guide pier is an arc-shaped pier set at the intersection of the branch tunnel and the main tunnel, and the guiding direction of the guide pier is tangent to the water flow direction of the main tunnel.

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