U-shaped communication stilling well structure and construction method thereof

Abstract

The application provides a U-shaped communication stilling well structure, wherein an energy dissipation area is arranged in the upstream well section of the stilling well, an outflow adjustment area is arranged in the downstream well section of the stilling well, and the upstream and downstream corners of the stilling well are connected and transitioned in a circular arc mode; the inlet of the energy dissipation area of the stilling well is communicated with a vertical shaft; a pressure slope section is arranged in the upstream of the water outlet hole; the pressure slope section is communicated with the outlet of the side surface of the flow adjustment area of the stilling well; and the pressure slope section and the stilling well are smoothly connected and transitioned. The stilling well is divided into the energy dissipation area and the outflow adjustment area by the U-shaped rock wall, so that the water flow passing through the energy dissipation area is effectively dissipated, and the flow state of the water flow passing through the outflow adjustment area is improved. Therefore, the U-shaped communication stilling well can not only realize the high-efficiency energy dissipation effect, but also effectively improve the structural safety and reliability by effectively improving the flow state of the outflow water flow and reducing the water flow pulsation pressure.

Description

TECHNICAL FIELD

[0001] The present application relates to the vertical shaft spillway tunnel engineering technical field, and in particular to a U-shaped communication stilling well structure and a construction method thereof. BACKGROUND

[0002] The stilling well at the bottom of the vertical shaft is the main energy dissipation structure of the vertical shaft spillway tunnel, and can eliminate about 90% of the energy in the process of flood discharge. The side wall of the stilling well is connected to the tailrace tunnel. In order to control the flow state and flow velocity of the tailrace tunnel, a connection section about 20m long is usually arranged at the first section of the tailrace tunnel, and a pressure slope is usually arranged at the tail of the connection section. Since the inlet of the tailrace tunnel is directly connected to the energy dissipation rolling area, the water flow is turbulent, which makes the connection section have a heavy task of adjusting the flow state and has to withstand a large pulsating pressure, so the structural static and dynamic safety should be carefully considered. SUMMARY

[0003] The first object of the present application is to provide a stilling well structure for improving the flow state of the front section (including the pressure slope section) of the tailrace tunnel. To this end, the present application adopts the following technical solution:

[0004] The U-shaped communication stilling well structure sets a U-shaped stilling well between the vertical shaft and the tailrace tunnel, an energy dissipation zone is arranged in the upstream well section of the stilling well, an outflow adjustment zone is arranged in the downstream well section of the stilling well, and the upstream and downstream corners of the stilling well are connected and transitioned by a circular arc, the inlet of the energy dissipation zone of the stilling well is connected to the vertical shaft, a pressure slope section is arranged upstream of the tailrace tunnel, the pressure slope section is connected to the outlet on the side of the outflow adjustment zone of the stilling well, and a smooth connection section is arranged between the pressure slope section and the stilling well, so that the stilling well is in a state of energy dissipation and flow state improvement for the water flow passing through it.

[0005] Further, the radius of the upstream and downstream corners of the stilling well is not less than 1 times the length of the diameter of the stilling well.

[0006] Further, circular arc connection parts are arranged on both sides of the water surface of the smooth connection section, and an elliptical curve connection part is arranged at the bottom of the water surface of the smooth connection section.

[0007] Further, the thickness of the rock wall between the upstream well section and the downstream well section of the stilling well is not less than 2 times the diameter of the vertical shaft.

[0008] Further, a reinforced concrete lining is arranged inside the overall structure.

[0009] Further, a stilling well pressure regulating pipe is arranged on the top well wall of the outflow adjustment zone of the stilling well.

[0010] Further, the stilling well pressure regulating pipe connects the top of the outflow adjustment zone and the outside, the stilling well pressure regulating pipe and the reinforced concrete lining of the stilling well and the vertical shaft are arranged respectively, a first hole is horizontally arranged in the rock wall between the stilling well and the vertical shaft, and the middle section of the stilling well air pipe is buried in the first hole.

[0011] Further, the water outlet hole is provided with a water outlet hole air pipe.

[0012] Further, the water outlet hole air pipe connects the water outlet hole and the outside, the top of the pressure slope section is provided with a groove, the water outlet hole air pipe is arranged in the reinforced concrete lining of the groove and the shaft respectively, a second hole is arranged in the rock wall between the stilling well and the shaft, and the middle section of the water outlet hole air pipe is arranged in the second hole.

[0013] A second object of the present application is to provide a construction method which is simple and convenient and guarantees construction efficiency. To this end, the present application adopts the following technical scheme:

[0014] The construction method of the U-shaped connected stilling well structure has the following specific steps:

[0015] S1: simultaneously excavating both ends of the target excavation area, i.e. excavating from the head of the upstream inlet of the shaft and the downstream outlet of the water outlet hole, and finally excavating the stilling well;

[0016] S2: excavating the upstream and downstream shaft sections to the middle part of the stilling well, and thus making the upstream and downstream shaft sections of the stilling well through;

[0017] S3: burying and fixing the stilling well pressure regulating pipe and the water outlet hole air pipe, so as to make the stilling well pressure regulating pipe and the water outlet hole air pipe reach above the reservoir water level and communicate with the outside atmosphere;

[0018] S4: binding the lining steel bars of the overall structure and pouring the lining concrete.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] The present application divides the stilling well into the energy dissipation zone and the outflow adjustment zone by the U-shaped rock wall, so as to effectively dissipate the energy of the water flow passing through the energy dissipation zone, and improve the flow state of the water flow passing through the outflow adjustment zone. Therefore, the U-shaped connected stilling well of the present application not only has the effect of high-efficiency energy dissipation, but also effectively improves the flow state of the outflow water flow, reduces the water flow pulsation pressure, and effectively improves the structural safety and reliability. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is the overall structure elevation view of the present application;

[0022] Figure 2 is the overall structure elevation view of the present application Figure 1 is the section view at A-A in the present application;

[0023] Figure 3 is the section view at B-B in the present application; Figure 1

[0024] Figure 4 Figure 1 ​​Cross-sectional view at point CC.

[0025] The markings in the attached diagram are as follows: 1-Stress dissipation well; 11-Energy dissipation zone; 12-Outflow adjustment zone; 2-Vertical shaft; 3-Slope section; 31-Smooth connection section; 4-Drainage tunnel; 5-Reinforced concrete lining; 6-Stress dissipation well pressure regulating pipe; 7-Drainage tunnel vent pipe; 71-Trough section; 8-Elliptical curve connection section; 9-Hole; 10-Structural expansion joint. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0027] like Figures 1-4 As shown, the U-shaped stilling well structure has a U-shaped stilling well 1 set between the vertical shaft 2 and the drainage tunnel 4. An energy dissipation zone 11 is set in the upstream section of the stilling well 1 to dissipate the energy of the violently turbulent water flow in the well. An outflow adjustment zone 12 is set in the downstream section of the stilling well 1 to improve the flow pattern of the water flow and thus control the flow pattern of the water flowing into the drainage tunnel 4. The upstream and downstream corners of the stilling well 1 are connected by a rounded transition. The inlet of the energy dissipation zone 11 of the stilling well 1 is connected to the vertical shaft 2. A slope section 3 is set in the upstream of the drainage tunnel 4. The slope section 3 is connected to the outlet on the side of the outflow adjustment zone 12 of the stilling well 1. A smooth connection section 31 is set between the slope section 3 and the stilling well 1 so that the stilling well 1 can dissipate energy and improve the flow pattern of the water flowing through it.

[0028] In this embodiment, the effective depth of energy dissipation varies with the changes in head and flow rate. The depth H of the stilling well 1 is taken as its maximum effective depth plus a certain safety margin. In this embodiment, the value is 5-20m. The final depth H of the stilling well 1 still needs to be verified and corrected according to the hydraulic model test.

[0029] In this embodiment, the U-shaped stilling well 1 has a circular cross-section, and its net diameter D is the same as that of the vertical shaft 2. To ensure the depth of the energy dissipation zone 11, the upper part of the sidewall of the upstream section of the stilling well 1 is made as vertical as possible, and the arc connection at the upstream corner must meet hydraulic requirements. The downstream corner of the stilling well 1 uses an arc transition with a radius not less than one times the diameter of the stilling well 1.

[0030] Specifically, the smooth connecting section 31 has arc-shaped connecting parts on both sides of the water-facing side, and an elliptical curve connecting part 8 at the bottom of the water-facing side. The elliptical curve connecting part 8 is a 1 / 4 elliptical curve. The radius of curvature of the arc-shaped connecting parts and the elliptical curve connecting part 8 in this area are designed based on hydraulic characteristics and structural stability, and ultimately need to be verified and corrected through hydraulic model tests.

[0031] Specifically, the thickness of the rock wall between the upstream and downstream sections of the stilling well 1 shall not be less than twice the diameter of the vertical shaft 2, i.e., B≥2D.

[0032] Specifically, the outer part of the overall structure is provided with a reinforced concrete lining 5, wherein the lining thickness is adaptively designed according to the hydraulic characteristics and structural stability; the reinforced concrete lining 5 of the embodiment adopts insect-resistant and wear-resistant concrete.

[0033] In the embodiment, no structural joint is arranged between the stilling well 1 and the smooth connection section 31 of the concrete of the vertical shaft 2 and the concrete of the pressure slope 3, and a construction joint can be arranged according to the construction requirement, and the steel bars pass through the joint. The structural expansion joint 10 is arranged at the outlet of the pressure slope section 3 and the position of the water withdrawal hole 4, and a copper sheet water stop is arranged, and construction joints are arranged at other positions according to the requirement, the steel bars pass through the joints, and a rubber water stop is arranged along the inner side of the joints.

[0034] As shown in Figure 1 In order to avoid that the gas at the top of the downstream cannot be discharged or a negative pressure area appears in the process of the water level rising of the stilling well 1, and the gas in the water withdrawal hole 4 cannot be discharged, a pressure regulating pipe and an air pipe are arranged in the overall structure. The air pipe is arranged in the reinforced concrete lining 5, and in order to make the air pipe more quickly and directly transition from the reinforced concrete lining 5 at the position of the stilling well 1 to the reinforced concrete lining 5 at the position of the vertical shaft 2, a hole 9 is horizontally arranged in the rock wall between the stilling well 1 and the vertical shaft 2, and the size of the hole 9 is greater than that of the pressure regulating pipe and the air pipe, and the hole 9 and the pressure regulating pipe and the air pipe are filled and compacted by grouting.

[0035] Specifically, the stilling well pressure regulating pipe 6 is arranged on the top wall of the stilling well 1 at the outlet adjusting area 12. The two ends of the stilling well pressure regulating pipe 6 are arranged in the reinforced concrete lining 5 of the stilling well 1 and the vertical shaft 2 respectively, a first hole is horizontally arranged in the rock wall between the stilling well 1 and the vertical shaft 2, and the middle section of the stilling well pressure regulating pipe 6 is buried in the first hole.

[0036] Specifically, the water withdrawal hole air pipe 7 is arranged on the side wall of the water withdrawal hole 4, and the water withdrawal hole air pipe 7 is sleeved with the water withdrawal hole air pipe 7 outside. The top of the pressure slope section 3 is provided with a groove 71, so that the two ends of the water withdrawal hole air pipe 7 are arranged in the groove 71 and the reinforced concrete lining 5 of the vertical shaft 2 respectively, a second hole is arranged in the rock wall between the stilling well 1 and the vertical shaft 2, and the middle section of the water withdrawal hole air pipe 7 is buried in the second hole.

[0037] The air pipe is made of steel pipe, the outer diameter is 1m, and the wall thickness is 8mm. The first hole and the second hole are arranged side by side, the center distance between the two is 2m, and the diameter of the first hole and the second hole is 1.2m.

[0038] Please refer to Figures 1-4 When the U-shaped communication stilling well structure is constructed, the specific steps are as follows:

[0039] S1: the shaft spillway (or shaft spillway tunnel) project adopts a construction method of excavating from both ends at the same time, starting from the upstream inlet of the shaft 2 and the downstream outlet of the water return tunnel 4, and finally excavating the stilling well 1; the simultaneous excavation and support cycle footage is determined according to the construction safety requirements and engineering geological conditions;

[0040] S2: the stilling well 1 adopts a construction method of symmetrically excavating from both ends, the difference in elevation between the two ends of the working face is not more than the depth of one cycle of blasting, and finally penetrates near the position of the B-B section shown in FIG. Figure 1 ;

[0041] S3: horizontal drilling is performed on the U-shaped rock wall to form a hole 9, so as to form a first hole and a second hole for installing the stilling well pressure regulating pipe 6 and the water return tunnel air pipe 7;

[0042] S4: a groove 71 is excavated on the top of the pressure slope section 3;

[0043] S5: the stilling well pressure regulating pipe 6 is pre-buried from the inlet of the shaft 2 to the top of the downstream of the stilling well 1, and the water return tunnel air pipe 7 is pre-buried to the outlet of the pressure slope section 3, both of which pass through the hole 9 between the U-shaped rock walls; and after the air pipes are fixed, the hole wall of the U-shaped rock wall hole 9 and the gap between the pressure regulating pipe and the air pipe are grouted to fix the air pipes passing through the U-shaped rock wall section;

[0044] S6: the lining steel bars are bound and the lining concrete is poured to form the reinforced concrete lining 5 outside the overall structure; at the same time, a structural expansion joint 10 is provided at the position where the pressure slope section 3 outlet connects the water return tunnel 4, and a copper sheet water stop is provided, and construction joints are provided at other positions as needed, the steel bars pass through the joints, and a rubber water stop is provided along the inner side of the joints.

[0045] The above embodiment is only one of the more optimal technical solutions of the present application, and those skilled in the art should understand that the technical solutions or parameters in the embodiment can be modified or replaced without departing from the principles and essence of the present application, and all should be covered within the protection scope of the present application.

Claims

1. A U-shaped communication stilling well structure, characterized by: The U-shaped stilling well (1) is arranged between the shaft (2) and the outfall hole (4) to make the stilling well (1) have the energy dissipation and flow state improvement to the water flow in the stilling well (1); the energy dissipation zone (11) is arranged in the upstream well section of the stilling well (1), the outflow adjustment zone (12) is arranged in the downstream well section of the stilling well (1), and the upstream and downstream corners of the stilling well (1) are connected in a circular arc transition; the inlet of the energy dissipation zone (11) of the stilling well (1) is communicated with the shaft (2), the pressure slope section (3) is arranged at the upstream of the outfall hole (4), the pressure slope section (3) is communicated with the outlet of the side surface of the outflow adjustment zone (12) of the stilling well (1), and the pressure slope section (3) and the stilling well (1) are arranged with the smooth connection section (31); The radius of the upstream and downstream corners of the stilling well (1) is not less than 1 times the hole diameter length of the stilling well (1); The inner wall of the overall structure is provided with the reinforced concrete lining (5).

2. The U-shaped communication stilling well structure according to claim 1, characterized in that: The smooth connection section (31) is provided with the circular arc connection part on the two sides of the water surface, and the bottom of the water surface of the smooth connection section (31) is provided with the elliptical curve connection part (8).

3. The U-shaped communication stilling well structure according to claim 1, characterized in that: The rock wall thickness between the upstream well section and the downstream well section of the stilling well (1) is not less than 2 times the diameter of the shaft (2).

4. The U-shaped communication stilling well structure according to claim 1, characterized in that: The stilling well pressure regulating pipe (6) is arranged on the top well wall of the outflow adjustment zone (12) of the stilling well (1).

5. The U-shaped communication stilling well structure according to claim 4, characterized in that: The stilling well pressure regulating pipe (6) is communicated with the top of the outflow adjustment zone (12) and the outside, the stilling well pressure regulating pipe (6) is arranged in the reinforced concrete lining (5) of the stilling well (1) and the shaft (2) respectively, a first hole is horizontally formed in the rock wall between the stilling well (1) and the shaft (2), and the middle section of the stilling well pressure regulating pipe (6) is buried in the first hole.

6. The U-shaped communication stilling well structure according to claim 5, characterized in that: The outfall hole vent pipe (7) is arranged at the top of the outfall hole (4).

7. The U-shaped communication stilling well structure according to claim 6, characterized in that: The outfall hole vent pipe (7) is communicated with the outfall hole (4) and the outside, the groove (71) is arranged at the top of the pressure slope section (3), the outfall hole vent pipe (7) is arranged in the reinforced concrete lining (5) of the groove (71) and the shaft (2) respectively, a second hole is formed in the rock wall between the stilling well (1) and the shaft (2), and the middle section of the outfall hole vent pipe (7) is buried in the second hole.

8. A construction method of a U-shaped communication stilling well structure, characterized by: The U-shaped communication stilling well structure is constructed according to the steps as follows: S1: the target excavation area is excavated from both ends, that is, the shaft (2) upstream inlet and the outfall hole (4) downstream outlet are excavated inward, and finally the stilling well (1) is excavated; S2: the upstream and downstream well sections of the stilling well (1) are excavated to the middle part, so that the upstream and downstream well sections of the stilling well (1) are connected; S3: the stilling well pressure regulating pipe (6) and the outfall hole vent pipe (7) are buried and fixed, and the stilling well pressure regulating pipe (6) and the outfall hole vent pipe (7) are communicated above the reservoir water level and communicated with the outside atmosphere; S4: the lining steel bars of the overall structure are bound and the lining concrete is poured.

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