U-shaped communicated stilling well structure and construction method thereof

Abstract

The invention provides a U-shaped communicated stilling well structure which is characterized in that an energy dissipation area is arranged in an upstream portion well section of a stilling well, an outflow adjusting area is arranged in a downstream portion well section of the stilling well, an upstream corner and a downstream corner of the stilling well are in arc connection transition, an inlet of the energy dissipation area of the stilling well is communicated with a vertical shaft, and a pressure slope section is arranged on the upstream portion of a recession tunnel. The pressing slope section is communicated with an outlet in the side face of a flow adjusting area of the stilling well, and the pressing slope section and the stilling well are provided with smooth connection sections. The stilling well is divided into the energy dissipation area and the outflow adjusting area through the stilling well and the U-shaped rock wall, so that energy of water flow flowing through the energy dissipation area is effectively dissipated, and meanwhile the flow state of the water flow flowing through the outflow adjusting area is improved. Therefore, the U-shaped communicated stilling well not only can achieve the efficient energy dissipation effect, but also effectively improves the structural safety and reliability by effectively improving the flow state of outflow water flow and reducing the water flow pulsating pressure.

Description

Technical Field

[0001] The invention relates to the technical field of vertical shaft type flood discharge tunnel engineering, and in particular to a U-shaped connected stilling well structure and a construction method thereof. Background Art

[0002] The stilling well at the bottom of the shaft is the main energy dissipation structure of the shaft-type flood discharge tunnel, which can dissipate about 90% of the energy during the flood discharge process. The side wall of the stilling well is connected to the drainage tunnel. In order to control the flow pattern and flow velocity of the drainage tunnel, a connection section of about 20m in length is usually set at the first section of the drainage tunnel, and a pressure slope is often set at its tail. Since the inlet of the drainage tunnel is directly connected to the energy dissipation tumbling zone, the water flow is turbulent, which makes the flow pattern adjustment task of this connection section heavy and must withstand large pulsating pressure. The static and dynamic safety of its structure should be carefully considered. Summary of the invention

[0003] The first object of the present invention is to provide a stilling well structure for improving the flow pattern of water in the front section (including the pressure slope section) of the water withdrawal tunnel. To this end, the present invention adopts the following technical solutions:

[0004] A U-shaped connected energy dissipation well structure is provided between the vertical shaft and the water withdrawal tunnel. An energy dissipation zone is provided in the upstream section of the energy dissipation well, and an outflow adjustment zone is provided in the downstream section of the energy dissipation well. The upstream and downstream corners of the energy dissipation well are connected and transitioned in a circular arc. The inlet of the energy dissipation zone of the energy dissipation well is connected with the vertical shaft. A slope pressure section is provided upstream of the water withdrawal tunnel. The slope pressure section is connected with the outlet on the side of the outflow adjustment zone of the energy dissipation well. A smooth connection section is provided between the slope pressure section and the energy dissipation well, so that the energy dissipation well can dissipate energy and improve the flow state of the water flowing through it.

[0005] Furthermore: the upstream and downstream corner radii of the energy dissipation well are not less than 1 times the hole diameter length of the energy dissipation well.

[0006] Furthermore: arc connecting parts are arranged on both sides of the water-facing surface of the smooth connecting section, and an elliptical curve connecting part is arranged at the bottom of the water-facing surface of the smooth connecting section.

[0007] Furthermore: the thickness of the rock wall between the upstream section and the downstream section of the energy dissipation well is not less than 2 times the diameter of the vertical well.

[0008] Furthermore: a reinforced concrete lining is arranged inside the overall structure.

[0009] Furthermore: an energy dissipation well pressure regulating pipe is arranged on the top well wall of the outflow adjustment zone of the energy dissipation well.

[0010] Furthermore: the energy dissipation well pressure regulating pipe connects the top of the outflow adjustment area with the outside world, the energy dissipation well pressure regulating pipe is respectively arranged in the reinforced concrete lining of the energy dissipation well and the vertical shaft, and a first hole is horizontally opened in the rock wall between the energy dissipation well and the vertical shaft, and the middle section of the energy dissipation well ventilation pipe is buried in the first hole.

[0011] Furthermore: a drainage hole ventilation pipe is arranged on the top of the drainage hole.

[0012] Furthermore: the drainage tunnel ventilation pipe connects the drainage tunnel with the outside world, a groove is set at the top of the slope pressure section, the drainage tunnel ventilation pipe is respectively set in the groove and the reinforced concrete lining of the vertical shaft, and a second hole is opened in the rock wall between the energy dissipation well and the vertical shaft, and the middle section of the drainage tunnel ventilation pipe is buried in the second hole.

[0013] The second object of the present invention is to provide a construction method that is simple, convenient and efficient. To this end, the present invention adopts the following technical solutions:

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

[0015] S1: Excavate at both ends of the target excavation area simultaneously, that is, from the head of the upstream inlet of the shaft and the downstream outlet of the drainage tunnel, and finally excavate the energy dissipation well;

[0016] S2: The upstream and downstream sections of the stilling well are excavated toward the middle part, thereby connecting the upstream and downstream sections of the stilling well;

[0017] S3: bury and fix the pressure regulating pipe of the stilling well and the ventilation pipe of the water withdrawal tunnel to make the pressure regulating pipe of the stilling well and the ventilation pipe of the water withdrawal tunnel reach above the reservoir water level and communicate with the outside atmosphere;

[0018] S4: Tie lining steel bars to the overall structure and pour lining concrete.

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

[0020] The present invention divides the energy dissipation well into an energy dissipation zone and an outflow adjustment zone by using an energy dissipation well and a U-shaped rock wall, so as to effectively dissipate the energy of the water flowing through the energy dissipation zone, and at the same time improve the flow state of the water flowing through the outflow adjustment zone. Therefore, the U-shaped connected energy dissipation well of the present invention can not only achieve a high-efficiency energy dissipation effect, but also effectively improve the safety and reliability of the structure by effectively improving the outflow flow state and reducing the pulsating pressure of the water flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a vertical elevation view of the overall structure of the present invention;

[0022] Figure 2 For the present invention Figure 1 Cross-section at AA in the middle;

[0023] Figure 3 For the present invention Figure 1 Cross-section at the middle BB;

[0024] Figure 4 For the present invention Figure 1Cross-section at CC.

[0025] The markings in the attached figure are: 1-energy dissipation well; 11-energy dissipation area; 12-outflow adjustment area; 2-vertical shaft; 3-slope pressure section; 31-smooth connection section; 4-water withdrawal tunnel; 5-reinforced concrete lining; 6-energy dissipation well pressure regulating pipe; 7-water withdrawal tunnel vent pipe; 71-groove; 8-elliptical curve connection part; 9-hole; 10-structural expansion joint. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0027] like Figure 1-4 As shown, a U-shaped connected energy dissipation well structure is provided between the vertical shaft 2 and the water withdrawal tunnel 4. An energy dissipation zone 11 is provided in the upstream section of the energy dissipation well 1 to dissipate the energy of the violently turbulent water flow in the well; an outflow adjustment zone 12 is provided in the downstream section of the energy dissipation well 1 to improve the flow pattern of the water flow, thereby controlling the flow pattern of the water flow into the water withdrawal tunnel 4; the upstream and downstream corners of the energy dissipation well 1 are connected and transitioned in a circular arc, the inlet of the energy dissipation zone 11 of the energy dissipation well 1 is connected with the vertical shaft 2, a pressure slope section 3 is provided upstream of the water withdrawal tunnel 4, the pressure slope section 3 is connected with the outlet on the side of the outflow adjustment zone 12 of the energy dissipation well 1, and a smooth connection section 31 is provided between the pressure slope section 3 and the energy dissipation well 1, so that the energy dissipation well 1 can dissipate energy and improve the flow pattern of the water flow flowing through it.

[0028] In this embodiment, the effective depth of energy dissipation varies with the change of water head and flow rate. The depth H of the energy dissipation 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 energy dissipation well 1 still needs to be verified and corrected according to the hydraulic model test.

[0029] In this embodiment, the cross section of the U-shaped energy dissipation well 1 is a circular structure, and the clearance diameter D of the energy dissipation well 1 is the same as the clearance diameter of the vertical shaft 2. In order to ensure the depth of the energy dissipation zone 11, the upper part of the side wall of the upstream part of the energy dissipation well 1 adopts a vertical surface as much as possible, and the arc connection at the upstream corner must meet the hydraulic requirements. The downstream corner of the energy dissipation well 1 adopts an arc transition with a radius not less than one time the length of the hole diameter of the energy dissipation well 1.

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

[0031] Specifically, the thickness of the rock wall between the upstream section and the downstream section of the energy dissipation well 1 is not less than twice the diameter of the vertical well 2, that is, B≥2D.

[0032] Specifically, a reinforced concrete lining 5 is arranged outside the overall structure, wherein the lining thickness is adaptively designed according to hydraulic characteristics and structural stability; the reinforced concrete lining 5 of this embodiment is made of insect-resistant and wear-resistant concrete.

[0033] In this embodiment, there is no structural joint between the concrete of the energy dissipation well 1 and the shaft 2 and the concrete of the smooth connection section 31 of the pressure slope 3. Construction joints and steel bars can be provided according to construction requirements. Among them, a structural expansion joint 10 is provided at the position where the outlet of the pressure slope section 3 connects to the drainage tunnel 4, and a copper sheet water stop is provided. Construction joints are provided at other locations as needed, steel bars are provided, and a rubber water stop is provided along the inner side of the joint.

[0034] like Figure 1 As shown, in this embodiment, in order to prevent the gas at the top of the downstream from being unable to be discharged or a negative pressure zone from appearing during the rising of the water level in the stilling well 1, and to prevent the gas in the water withdrawal tunnel 4 from being unable to be discharged, a pressure regulating pipe and a vent pipe are arranged on the overall structure. The vent pipe is arranged in the reinforced concrete lining 5, and at the same time, in order to make the vent pipe 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 shaft 2 more quickly and directly, a hole 9 is horizontally arranged in the rock wall between the stilling well 1 and the shaft 2, and the size of the hole 9 is larger than the size of the pressure regulating pipe and the vent pipe, and at the same time, the grouting filling between the hole 9 and the pressure regulating pipe and the vent pipe is dense.

[0035] Specifically, the stilling well 1 is provided with a stilling well pressure regulating pipe 6 on the top wall of the outflow adjustment area 12 thereof. The two ends of the stilling well pressure regulating pipe 6 are respectively arranged in the reinforced concrete lining 5 on the stilling well 1 and the vertical shaft 2, and a first hole is horizontally opened 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, a drainage tunnel vent pipe 7 is provided on the side wall of the drainage tunnel 4, and a drainage tunnel vent pipe 7 is sleeved on the outside of the drainage tunnel vent pipe 7. A groove 71 is provided on the top of the slope pressure section 3, so that the two ends of the drainage tunnel vent pipe 7 are respectively arranged in the groove 71 and the reinforced concrete lining 5 on the shaft 2, and a second hole is opened in the rock wall between the stilling well 1 and the shaft 2, and the middle section of the drainage tunnel vent pipe 7 is buried in the second hole.

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

[0038] See also Figure 1-4 When constructing the U-shaped connected energy dissipation well structure, the specific steps are as follows:

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

[0040] S2: The energy dissipation well 1 is constructed by symmetrical excavation from both ends. The height difference of the two ends of the tunnel face does not exceed the depth of one cycle of blasting. Figure 1 The BB section shown in FIG. is penetrated near the position;

[0041] S3: drilling horizontally 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 pressure regulating pipe 6 of the energy dissipation well and the ventilation pipe 7 of the water withdrawal tunnel;

[0042] S4: Digging a groove 71 at the top of the slope pressing section 3;

[0043] S5: pre-buried the stilling well pressure regulating pipe 6 from the entrance of the shaft 2 to the top of the downstream of the stilling well 1, and pre-buried the drainage tunnel ventilation pipe 7 to the outlet of the pressure slope section 3, and both ventilation pipes pass through the hole 9 between the U-shaped rock walls; and after the ventilation pipes are fixed, grouting is performed on the wall of the hole 9 in the U-shaped rock wall and the gap between the pressure regulating pipe and the ventilation pipe to fix the ventilation pipe passing through the U-shaped rock wall section;

[0044] S6: Tie up the lining steel bars and pour the lining concrete to form the reinforced concrete lining 5 outside the overall structure; at the same time, set a structural expansion joint 10 at the position where the outlet of the pressure slope section 3 is connected to the drainage tunnel 4, and set a copper sheet water stop. Set construction joints at other locations as needed, pass the steel bars through the joints, and set a rubber water stop along the inside of the joints.

[0045] The above embodiment is only a preferred technical solution of the present invention. Those skilled in the art should understand that the technical solutions or parameters in the embodiments can be modified or replaced without departing from the principle and essence of the present invention, and all should be covered within the protection scope of the present invention.

Claims

1. U-shaped connected energy dissipation well structure, characterized by: A U-shaped energy dissipation well (1) is arranged between the vertical shaft (2) and the water withdrawal tunnel (4) so ​​that the energy dissipation well (1) dissipates energy and improves the flow state of the water flowing therein; an energy dissipation zone (11) is arranged in the upstream well section of the energy dissipation well (1), and an outflow adjustment zone (12) is arranged in the downstream well section of the energy dissipation well (1); the upstream and downstream corners of the energy dissipation well (1) are connected and transitioned in a circular arc; the inlet of the energy dissipation zone (11) of the energy dissipation well (1) is connected to the vertical shaft (2); a pressure slope section (3) is arranged upstream of the water withdrawal tunnel (4); the pressure slope section (3) is connected to the outlet on the side of the outflow adjustment zone (12) of the energy dissipation well (1); and a smooth connection section (31) is arranged between the pressure slope section (3) and the energy dissipation well (1).

2. The U-shaped connected energy dissipation well structure according to claim 1 is characterized in that: The upstream and downstream corner radii of the energy dissipation well (1) are not less than 1 times the hole diameter length of the energy dissipation well (1).

3. The U-shaped connected energy dissipation well structure according to claim 1 is characterized in that: Circular arc connecting parts are arranged on both sides of the water-facing surface of the smooth connecting section (31), and an elliptical curve connecting part (8) is arranged at the bottom of the water-facing surface of the smooth connecting section (31).

4. The U-shaped connected energy dissipation well structure according to claim 1 is characterized in that: The thickness of the rock wall between the upstream well section and the downstream well section of the energy dissipation well (1) is not less than twice the diameter of the vertical well (2).

5. The U-shaped connected energy dissipation well structure according to claim 1 is characterized in that: The inner wall of the integral structure is provided with a reinforced concrete lining (5).

6. The U-shaped connected energy dissipation well structure according to claim 5 is characterized in that: The energy dissipation well (1) is provided with an energy dissipation well pressure regulating pipe (6) on the top well wall of the outflow adjustment area (12) thereof.

7. The U-shaped connected energy dissipation well structure according to claim 6 is characterized in that: The energy dissipation well pressure regulating pipe (6) connects the top of the outflow adjustment area (12) with the outside world. The energy dissipation well pressure regulating pipe (6) is respectively arranged in the reinforced concrete lining (5) on the energy dissipation well (1) and the vertical shaft (2). A first hole is horizontally opened in the rock wall between the energy dissipation well (1) and the vertical shaft (2), and the middle section of the energy dissipation well ventilation pipe (6) is buried in the first hole.

8. The U-shaped connected energy dissipation well structure according to claim 5 is characterized in that: A water retreat hole vent pipe (7) is provided at the top of the water retreat hole (4).

9. The U-shaped connected energy dissipation well structure according to claim 8 is characterized in that: The drainage tunnel vent pipe (7) connects the drainage tunnel (4) with the outside world. A groove (71) is provided at the top of the slope pressure section (3). The drainage tunnel vent pipe (7) is respectively provided in the groove (71) and in the reinforced concrete lining (5) on the vertical shaft (2). A second hole is provided in the rock wall between the energy dissipation well (1) and the vertical shaft (2), and the middle section of the drainage tunnel vent pipe (7) is buried in the second hole.

10. The construction method of the U-shaped connected energy dissipation well structure is characterized by: The U-shaped connected energy dissipation well structure as described in any one of claims 1 to 9 is used for construction, and the specific steps are as follows: S1: Excavate at both ends of the target excavation area simultaneously, i.e., construct from the head of the upstream inlet of the shaft (2) and the downstream outlet of the drainage tunnel (4) inwards, and finally excavate the energy dissipation well (1); S2: The upstream and downstream sections of the energy dissipation well (1) are excavated toward the middle part thereof, thereby making the upstream and downstream sections of the energy dissipation well (1) connected; S3: burying and fixing the stilling well pressure regulating pipe (6) and the water withdrawal tunnel vent pipe (7), and making the stilling well pressure regulating pipe (6) and the water withdrawal tunnel vent pipe (7) pass to above the reservoir water level and communicate with the outside atmosphere; S4: Tie lining steel bars to the overall structure and pour lining concrete.

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