Radius excavation arch end structure and excavation method for connecting arch dam with bedrock

Abstract

The present invention relates to a radial excavation arch end structure connecting an arch dam with bedrock and an excavation method thereof; the structure comprises an arch dam and arch seats arranged at two arch ends of the arch dam; a central contact point formed by the intersection of the arch dam center line of the arch dam and the arch seats at both ends; an upstream contact point formed by the intersection of the upstream side of the arch dam and the arch seats at both ends, and a contact surface formed between the arch dam and the arch seat between the central contact point and the upstream contact point is a first arc surface; the first arc surface is tangent to the radial line of the arch dam center line; the contact surface of the arch seat on the downstream side of the arch dam is extended downward, and the end point of the extension is connected to the thickened starting point of the downstream side of the arch dam to form a second arc surface; the second arc surface intersects with the radial line of the arch dam center line. The arch end upstream of the arch ring center line of the present invention adopts an arc shape, which is not only conducive to the force transmission of the arch end, but also forms a radial excavation, which is conducive to reducing the amount of rock excavation on the upstream face of the dam body.

Description

Technical Field

[0001] The invention relates to an arch dam of a water conservancy and hydropower project, and in particular to a radially excavated arch end structure connecting the arch dam and bedrock and an excavation method thereof. Background Art

[0002] An arch dam is an arch-shaped water-retaining structure that bulges upstream on a plane. It uses the action of the arch to transfer all or part of the water pressure load to the bedrock on both sides of the river valley. The horizontal section of the arch dam is composed of a curved arch, with both ends supported on the bedrock on both sides. The vertical section is in the form of a cantilever beam, with the bottom sitting on the riverbed or the bedrock on both sides. Arch dams generally rely on the action of the arch, that is, the reaction force of the arch seats at both ends, and also rely on their own weight to maintain the stability of the dam body.

[0003] The contact surface between the arch end and the bedrock is generally excavated into a full radius so that the arch end thrust is close to perpendicular to the arch seat surface (such as Figure 1 In the lower arch of the dam body, if the full radius is used for excavation, the upstream rock mass will be excavated too much. Therefore, from the perspective of saving excavation volume, the contact surface between the arch end and the bedrock can be excavated in the radius direction (such as Figure 2 ), that is, the excavation surface upstream of the arch ring centerline rotates an angle toward the riverbed, and the excavation surface downstream of the arch ring centerline still adopts radial excavation, so it is called radial excavation. Radial excavation can save the excavation area of ​​the upstream face of the arch dam ( Figure 2 ).

[0004] From the stress state of the arch dam, tensile stress appears on the upstream surface of the arch end and compressive stress appears on the downstream surface. Therefore, the optimization direction of the arch end structure is as follows:

[0005] 1) The upstream surface gradually changes from full radius to abutment from the dam crest downward to radius to abutment;

[0006] 2) To reduce the compressive stress on the downstream surface, appropriately thicken the downstream side of the arch end. Summary of the invention

[0007] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a radially excavated arch end structure for connecting an arch dam with bedrock and an excavation method thereof.

[0008] To achieve the above-mentioned purpose, the present invention designs a radially excavated arch end structure connecting an arch dam and bedrock, which includes an arch dam and arch seats arranged at the two arch ends of the arch dam; a central contact point formed by the intersection of the arch dam centerline of the arch dam and the arch seats at both ends; an upstream contact point formed by the intersection of the upstream side of the arch dam and the arch seats at both ends, and a contact surface between the arch dam and the arch seats between the central contact point and the upstream contact point is a first arc surface; the first arc surface is tangent to the radial line of the arch dam centerline (the radial line is the contact surface between the arch dam and the arch seat); the contact surface between the downstream side of the arch dam and the arch seat is extended downward and the end point of the extension is connected to the thickened starting point of the downstream side of the arch dam to form a second arc surface; the second arc surface intersects with the radial line of the arch dam centerline.

[0009] Furthermore, the radius R1 of the first arc surface is 1-2 times the thickness of the crown.

[0010] Furthermore, an angle α between a straight line connecting a starting point and an end point of the first arc surface and a radial line of a center line of the arch dam is 5-15°.

[0011] Furthermore, an angle α between a straight line connecting the starting point and the end point of the first arc surface and a radial line of the center line of the arch dam is 10°.

[0012] Furthermore, the vertical distance between the thickening starting point of the second arc surface and the arch end is 0.5-1 times the thickness of the arch crown.

[0013] Furthermore, the radius R2 of the second arc surface is 2-3 times the thickness of the crown.

[0014] The present invention also provides a method for excavating a radius excavation arch end structure for connecting the arch dam with the bedrock, comprising the following steps:

[0015] 1) Select the location of the arch dam and arch end according to the geological conditions of the arch seat;

[0016] 2) According to the stress state of the arch dam, select the excavation position and arc radius of the arch end radius;

[0017] 3) Set the radius excavation angle;

[0018] 4) The arc thickening method is used on the downstream surface of the arch dam to improve the stress state of the downstream surface of the arch dam.

[0019] As a preferred solution, in step 2), the position of the radial excavation of the arch end is the center line of the arch dam, and the radius of the first arc surface is 1-2 times the thickness of the arch crown.

[0020] As a preferred solution, in step 3), the radial excavation angle is 5-15°, preferably 10°.

[0021] As a preferred solution, in step 4), the vertical distance between the thickening starting point of the second arc surface and the arch end is 0.5-1 times the thickness of the arch crown, and the radius of the second arc surface is 2-3 times the thickness of the arch crown.

[0022] Beneficial effects of the present invention:

[0023] 1. The arch end upstream of the arch ring centerline of the present invention adopts an arc shape, which is not only conducive to the force transmission of the arch end, but also forms a radial excavation, which is conducive to reducing the amount of rock excavation on the upstream surface of the dam body.

[0024] 2. The downstream surface of the arch ring of the present invention is thickened in a circular arc shape, which not only thickens the dam body, reduces the compressive stress on the downstream surface of the arch end, improves the stress state, but also reduces the volume of concrete in the dam body compared with the linear thickening method. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the plan view of the arch ring of a general arch dam (radial excavation at the arch end);

[0026] Figure 2 It is the plan view of the arch ring of a general arch dam (excavation in the radius direction of the arch end);

[0027] Figure 3 Yes, the smooth abutment structure diagram;

[0028] Figure 4 This is the large-scale drawing of the smooth arch seat at the arch end;

[0029] Figure 5 It is a schematic diagram of the smooth body excavated at the radial angle on the upstream side of the arch end;

[0030] Figure 6 It is a schematic diagram of the smooth body of the thickened arch end on the downstream side of the arch end;

[0031] In the figure, the arch dam centerline 1.1, the upstream side 1.2, the first arc surface 1.3, the downstream side 1.4, the second arc surface 1.5, the arch seat 2, the upstream surface excavation line 3, the terrain line 4, and the downstream surface excavation line 5. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below in conjunction with specific embodiments so that those skilled in the art can understand.

[0033] like Figures 3-4The arch dam shown is a radial excavation arch end structure connected to the bedrock, which includes an arch dam 1 and arch seats 2 arranged at the two arch ends of the arch dam; the central contact point formed by the intersection of the arch dam centerline 1.1 of the arch dam and the arch seats at both ends is point O; the upstream contact point formed by the intersection of the upstream side 1.2 of the arch dam and the arch seats at both ends is point B, and the contact surface formed by the arch dam and the arch seat 2 between the contact point O and the contact point B is the first arc surface 1.3; the first arc surface 1.3 is tangent to the radial line AC of the arch dam centerline 1.1 (the radial line is the contact surface between the arch dam and the arch seat); the radius R1 of the first arc surface 1.3 is 1-2 times the thickness of the arch crown (AC straight line). The angle α between the straight line connecting the starting point O and the end point B of the first arc surface 1.3 and the radial line OA of the arch dam centerline 1.1 is 10°.

[0034] The contact surface between the downstream side 1.4 of the arch dam and the arch seat 2 is horizontally extended downward, and the end point E of the extension is connected with the thickening starting point D of the downstream side 1.4 of the arch dam to form a second arc surface 1.5; the second arc surface 1.5 intersects with the radial line (AC line) of the center line 1.1 of the arch dam;

[0035] The vertical distance between the thickening starting point D of the second arc surface 1.5 and the arch seat 2 is 0.5-1 times the thickness of the arch crown; the radius R2 of the second arc surface 1.5 is 2-3 times the thickness of the arch crown.

[0036] like Figures 5-6 The excavation method of the radius excavation arch end structure for connecting the arch dam with the bedrock shown includes the following steps:

[0037] 1) Select the location of the arch dam and the arch seat 2 according to the geological conditions of the arch seat;

[0038] 2) According to the stress state of the arch dam, the position of the arch end radial excavation and the arc radius are selected; wherein, the position of the arch end radial excavation is the arch dam centerline 1.1, and the radius R1 of the first arc surface 1.2 is 1-2 times the thickness of the arch crown;

[0039] 3) Setting the radial excavation angle; wherein the radial excavation angle α is 10°;

[0040] 4) The arc thickening method is adopted for the downstream surface of the arch dam to improve the stress state of the downstream surface of the arch dam, wherein the vertical distance between the thickening starting point D of the second arc surface 1.5 and the arch end is 0.5-1 times the thickness of the arch crown, and the radius R2 of the second arc surface 1.5 is 2-3 times the thickness of the arch crown.

[0041] Although the above embodiments have been described in detail, they are only a part of the embodiments of the present invention, not all of them. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all belong to the protection scope of the present invention.

Claims

1. A radially excavated arch end structure for connecting an arch dam to bedrock, comprising an arch dam (1) and arch seats (2) arranged at two arch ends of the arch dam; characterized in that: The arch dam center line (1.1) of the arch dam intersects with the arch seats (2) at both ends to form a center contact point; the upstream side (1.2) of the arch dam intersects with the arch seats (2) at both ends to form an upstream contact point, and the contact surface formed by the arch dam and the arch seat (2) between the center contact point and the upstream contact point is a first arc surface (1.3); the first arc surface (1.3) is tangent to a radial line of the arch dam center line (1.1); the contact surface between the downstream side (1.4) of the arch dam and the arch seat (2) is extended downward, and the end point of the extension is connected to the thickening starting point of the downstream side (1.4) of the arch dam to form a second arc surface (1.5); the second arc surface (1.5) intersects with a radial line of the arch dam center line (1.1).

2. The radial excavation arch end structure for connecting the arch dam to the bedrock according to claim 1, characterized in that: The radius R1 of the first arc surface (1.3) is 1-2 times the thickness of the crown.

3. The radial excavation arch end structure for connecting the arch dam to the bedrock according to claim 1, characterized in that: The angle α between the straight line formed by connecting the starting point and the end point of the first arc surface (1.3) and the radial line of the arch dam center line (1.1) is 5-15°.

4. The radial excavation arch end structure for connecting the arch dam to the bedrock according to claim 1, characterized in that: The angle α between the straight line formed by connecting the starting point and the end point of the first arc surface (1.3) and the radial line of the arch dam center line (1.1) is 10°.

5. The radial excavation arch end structure for connecting the arch dam to the bedrock according to claim 1, characterized in that: The vertical distance between the thickening starting point of the second arc surface (1.5) and the arch seat (2) is 0.5-1 times the thickness of the arch crown.

6. The radial excavation arch end structure for connecting the arch dam to the bedrock according to claim 1, characterized in that: The radius R2 of the second arc surface (1.5) is 2-3 times the thickness of the crown.

7. A method for excavating a radial excavation arch end structure for connecting an arch dam with bedrock as claimed in claim 1, characterized in that: The following steps are involved: 1) Select the location of the arch dam and arch end (2) according to the geological conditions of the arch seat; 2) According to the stress state of the arch dam, select the excavation position and arc radius of the arch end radius; 3) Set the radius excavation angle; 4) The arc thickening method is used on the downstream surface of the arch dam to improve the stress state of the downstream surface of the arch dam.

8. The method for excavating the arch end structure in the radial direction of the arch dam connected to the bedrock according to claim 7, characterized in that: In the step (2), the position of the arch end radial excavation is the center line of the arch dam, and the radius of the first arc surface (1.2) is 1-2 times the thickness of the arch crown.

9. The method for excavating the arch end structure in the radial direction of the arch dam connecting the arch dam and the bedrock according to claim 7, characterized in that: In the step (3), the radial excavation angle is 5-15°.

10. The method for excavating the arch end structure in the radial direction for connecting the arch dam with the bedrock according to claim 7, characterized in that: In the step (4), the vertical distance between the thickening starting point of the second arc surface (1.5) and the arch end is 0.5-1 times the thickness of the arch crown, and the radius of the second arc surface (1.5) is 2-3 times the thickness of the arch crown.

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